A close view of the star-forming region 30 Doradus, located in the heart of the Tarantula Nebula. Wide Field Camera 3 Contents [edit this]

1 ...... Annex A: Hubble: Current Performance and Future Expectation 1 ...... A.1. The History of Hubble 5 ...... A.2. The Present: Hubble Observatory and Science 5 ...... A.2.1. Hubble Observatory: Servicing Mission 4 8 ...... A.2.2. Science Instruments 10 ...... A.3. Hubble Science after Servicing Mission 4 10 ...... A.3.1. Highlights of Recent Exciting Discoveries 12 ...... A.3.2. Maximizing Hubble’s Scientific Return: The Multi Cycle Treasury Programs 13 ...... A.3.3.1. Panchromatic Hubble Andromeda Treasury Survey (PHAT) 14 ...... A.3.3.2. Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) 15...... A.3.3.3. Cluster Lensing and Supernova Survey with Hubble (CLASH) 16 ...... A.3.3.4. Dark Energy and MCT Supernova Search

18 ...... A.4. The Future: Hubble Observatory and Science Instrument Performance Expectations 18 ...... A.4.1. Science Instrument Lifetime Predictions 19 ...... A.4.2. Hubble Observatory Lifetime Predictions 19 ...... A.4.2.1. Fine Guidance Sensors 19 ...... A.4.2.2. Gyros 19 ...... A.4.2.3. Batteries 19 ...... A.4.2.4. Other Subsystems 20 ...... A.4.3. Mission Life Extension Activities

22 ...... A.5. A Leap Forward: Future Scientific Initiatives 22 ...... A.5.1. Ultra-Deep Fields 24 ...... A.5.2. Ultraviolet Astrophysics Legacy Program 25 ...... A.5.3. The HST Source Catalog

29 ...... Annex B: Impact of Hubble on Science 29 ...... B.1. Impact of Hubble on Science: Metrics 29 ...... B.1.1. Publications and Citations 31 ...... B.1.2. Proposal Pressure and European Success

33 ...... B.2. Hubble in the Media 33 ...... B.2.1. Science Releases 34 ...... B.2.2. Pictures of the Week A stellar field in theSagittarius 35 ...... B.2.3. Podcasts Window. 36 ...... B.2.4. Social Media 37 ...... B.2.5. Other Initiatives Advanced Camera for Surveys / 37 ...... B.2.5.1. The Hubble Hidden Treasure Competition Wide Field Channel 41 ...... Annex C: The Scientific Impact of the Hubble Archive

41 ...... C.1. The Hubble Archive Contents, continued

47 ...... Annex D: Synergy — Working together with Other Missions 48 ...... D.1. Synergy between Hubble and JWST 49 ...... D.1. Synergy between Hubble and Planet-finding Missions

53 ...... Annex E: The Cost of Hubble’s Extension to ESA 53 ...... E.1. Cost of Hubble’s Extension (2013–2014) to ESA

57 ...... Annex F: Supporting Documentation 57 ...... F.1. Letter from Mr. Mansoor Ahmed, Associate Director, Astrophysics Projects Division, National Aeronautics and Space Administration, Goddard Space Flight Center 59...... F.2. Letter from Dr. Mario Mateo, University of Michigan Department of Astronomy 62...... F.3. Letter from Dr. Louis-Gregory Strolger, Chair, Hubble Space Telescope Users Committee, Associate Professor of Physics and Astronomy, Western Kentucky University 65 ...... Acknowledgments 66...... Acronyms 67...... Hubble image credits

NGC 2397, a classic spiral galaxy with long prominent dust lanes along the edges of its arms. Infrared image of the Hubble’s exquisite resolution allows the study of “Mystic Mountain” individual stars in nearby galaxies. in the Carina Nebula. Advanced Camera for Surveys Wide Field Camera 3 1

Annex A Hubble: Current Performance and Future Expectations

A.1. The History of Hubble he Hubble Space Telescope had its origins in the writings of Hermann Oberth in the 1920s and Lyman Spitzer in the 1940s. They suggested that T astronomy could benefit greatly from a telescope that viewed the Uni- verse from above Earth’s atmosphere. In the early 1960s interest increased in astronomy as a scientific discipline to be pursued from space, and momentum grew for development of a large orbiting telescope. In 1962, NASA asked the Space Science Board of the National Acade- my of Sciences to study and recommend future astronomy payloads. In 1965, the Space Science Board recommended that NASA develop a large space telescope. In the autumn of 1971, NASA began to do serious feasibility studies of a 3-m–aperture telescope called the Large Space Telescope (LST). The study results were favourable, and preliminary design was initiated in 1972. While the design grew in maturity, it also highlighted the problems related to building such a large telescope, in particular the difficulty of housing the spacecraft inside the Shuttle hold as well as carrying the weight that was already at the limit of the lift capa- bilities of the Shuttle. In addition the cost was growing at an alarming rate. As a result the telescope underwent a major descoping, the mirror size was reduced to 2.4 m and the US Congress mandated that NASA should seek international partnership in this project to limit the overall costs to the US. NASA HQ and Project personnel approached ESA in late 1973 with a request to consider participation in the LST in several different areas: spacecraft hardware, scientific instruments and science operations. Within ESA, a team was appointed to lead the study. Over a 2-year period a joint NASA/ESA team discussed a large number of options. Initial studies concentrated on the potential provision of a sci- entific instrument to be placed in the telescope’s focal plane. A first study looked at a number of instruments for possible cooperation, including a two-dimensional “Mystic Mountain,” in the Carina Nebula. spectrograph and an imaging camera optimised for the ultraviolet (UV). This ini- tial selection was subsequently narrowed down, through a series of discussions Wide Field Camera 3 within the ESA Astrophysics Working Group and with NASA, to the Faint Object Camera (FOC). This decision was prompted in part by the fact that this instrument required a detector imaging system that could work in a “photon counting mode” in order to fully exploit the LST’s imaging capabilities. At that time, Europe had 2 Hubble: Current Performance and Future Expectations Hubble: Current Performance and Future Expectations 33

a lead in this area, in that scientists at University College London The delay provided time to make some improvements, identified during testing, to 2 V – DATE APVD 1 telescope subsystems. On April 24, 1990, Hubble was finally launched into orbit LKHD had developed the only photon-counting imaging system in rou- . B IEWING FT , V LATCH

A

DOOR aboard the Space Shuttle Discovery. The telescope carried five instruments: The

NSIDE tine use for optical astronomy. I UTBOARD 88.73, O 2 AD EVISIONS AND R R 270°

IN Wide Field/Planetary Camera, the Goddard High Resolution Spectrograph, the Faint DESCRIPTION

+V2 The NASA/ESA joint working group, which was set up with 90- 11.02 11.02 26.36. DIM DIM DIM

DDED DDED DDED A A the task of establishing a Memorandum of Understanding (MOU) Object Camera, the Faint Object Spectrograph, and the High Speed Photometer. AA UANTUM YSTERESIS FFICIENCY NSTALLATION Q E H I C23 C19 F21 ZONE REV for the cooperation on LST, agreed that, in addition to the Faint Almost immediately after Hubble went into orbit, it became clear that something AD 90.8 R was seriously wrong. While the pictures were clearer than those of ground-based

360° Object Camera, a continuing contribution by Europe to the Tele- 180° 0° +V1 telescopes, they weren’t the pristine images promised. They were significantly blur- –V3 scope’s operation, and the provision of a major subsystem, the solar arrays, would be appropriate to allow ESA to secure a 15% rier than expected. Hubble’s primary mirror, polished so carefully over the course share of the observing time for European astronomers during the of a full year, had a flaw called “spherical aberration.” It was just slightly the wrong FT A (2) UTBOARD FT –V2 shape, causing the light that bounced off the centre of the mirror to focus in a dif- LUSTER NTENNA

O A FS- planned 10 years of operations. Further studies were conducted C A FOR UPPORT MERGENCY AND (FSS) EPLOYMENT AIN LECTRICAL ITTINGS ENSOSRS S OOKING OOKING F (3) -G S MBILICAL LECTRICAL MBILICAL MBILICAL EFLECTOR UN INS YSTEM ELLOW LECTRICAL LIGHT OW FSS-E E U ENT ANDRAIL URGE S (1) L (1) L Y R (2) NS L HST-D E U FSS-E U P S F ferent place than the light bouncing off the edge. The tiny flaw — about 1/50th the V H P by both parties throughout 1975 and 1976. The Hubble design STA 100.00 study was continued until 1977, when the US Congress gave the thickness of a sheet of paper, was enough to distort the view. TATIONS (TYP) TATION HST S S Fortunately, scientists and engineers were dealing with a well-understood opti-

INUS approval to build (Fig. A.1.1) and operate the observatory. ) RBITER IN (AS) . 2 = O 1250 M NO FHST cal problem — although in a wholly unique situation. And they designed a solution. HROUD 20A

AXIAL SI On the ESA side, the project’s feasibility study was completed 7 S S (138.00 . 1 S FT A NO FHST A series of small mirrors could be used to intercept the light reflecting off the mir-

.2 and the Agency’s Science Programme Committee (SPC) gave the NO .1 TRAP FGS NO ROUND S G WF/PC FGS ror, correct for the flaw, and bounce the light to the telescope’s science instruments. STA

238.00 go-ahead, subject to satisfactory negotiation of the MOU with )

IN ITTING 9 BAY QUIPMENT RUNNION F AND The Corrective Optics Space Telescope Axial Replacement, or COSTAR, could be STA (SSM-ES) T BAY 2 BAY BAY 8 BAY EEL 240.00 BAY 1 BAY FT the United States. BAY 10 BAY STA K A 299.425 (61.25 ECTION SSM E S STA installed in place of one of the telescope’s other instruments in order to correct 299.25 As the other four instruments destined for the Telescope were IVOT (2) S/A STA P OTA ECTION 320.00 BAY C BAY QUIPMENT S BAY A BAY BAY B BAY E BAY D BAY INGE to be selected through a NASA Announcement of Opportunity the images produced by the remaining instruments. Astronauts would also replace STA 337.75 72.30 ± Y HGA H 333.00 + X FT (2) (FS) ) IN -NS the Wide Field/Planetary Camera with a new version, the Wide Field and Planetary STA ATCH S/A A L (AO) process, NASA requested that a team of scientists and engi- 377.562 HELL F.S. (2), S RAPPLE

RUNNION AND STA 358.00 (Lockheed Martin Space 1981) Company, D ’ IXTURE (156.05 Camera 2 (WFPC2) that contained small mirrors to correct for the aberration.

EQ STA NTENNA neers be allowed to visit Europe to review its ability to provide 393.30 N.S. F • RMS G • FWD T A ORWARD F ) GAIN - (2) IGH (HGA_, 2 R H

TOWED Astronauts spent 11 months training for one of the most complex space mis- RRAY the Faint Object Camera. This review team visited eight establish- A TOWED S OLAR (SA) (S S STA 455.30 sions ever attempted. In addition to the critical nature of the mission, it would be WD (2) ments in Europe (ESA and ESA Contractors) over a 10-day period STA ATCH 476.735 S/A F L in June 1976 and subsequently submitted a positive report. the first test of the telescope’s vaunted ability to be serviced and repaired in space. (4) ) (LS) IN ATACH CUFF (2) On December 2, 1993, the Space Shuttle Endeavor carried a crew of seven into orbit S

STA The Memorandum of Understanding between NASA and ESA LATE 492.824 +X 68.242 ±Z 535.00 WD 14.050 ±Y P SHIELD HGA L F

(153.20 IGHT (1) for Servicing Mission 1 that would involve 5 days of spacewalks and repairs. They L ANDRAIL was signed in October 1977. It guaranteed European astrono- H ATCH L PERTURE A OOR D mers from ESA Member States a minimum of 15% of the avail- removed the High Speed Photometer and replaced it with COSTAR. They replaced STA 608.5 STA 610.81 V1 able observing time, to be allocated through a peer-review pro- the original Wide Field Camera with the newer WFPC2, which corrected the blurry (2) ED FS REEN (2) ENSOR AND S INGE WD EFLECTOR F LUSTER FS– R UN H R NS C NS– G D S A 610.93 +X 57.40 +Y cess in exchange for the provision of the Faint Object Camera, image. They performed a host of other tasks, replacing solar panels, flight computer, the solar arrays, and the continued operations support for the fuse plugs, and other hardware. The replacements for the original solar panels were ATCH 11.02 again provided by ESA. These replacements were intended to significantly reduce L duration of the MOU. OOR 88.73 R 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 D ORT (2) Fig. A.1.1. Diagram of the Space Telescope. of the Space A.1.1. Diagram Fig. P RAILS OVER

RYOGENIC the jitter of the entire telescope, which had plagued observations since its launch. SI ENT C C V In 1981, the Space Telescope Science Institute (STScI) was es- –V2 XIAL NTENNA A (LMSC) A RAILS

SI TRANSFER AVEGUIDE GAIN - W (PE) XIAL NASA released the first new images from Hubble’s fixed optics on January 13, OW A

L tablished in Baltimore, Maryland, to evaluate proposals for tele- TRANSFER 9A 7 scope time and manage the science programme. By 1982, the first 1994. The pictures were beautiful; their resolution, excellent. Hubble was trans-

26.36 formed into the telescope that had been originally promised (Fig. A.1.2).

(4) ESA staff member took up duty at STScI as part of the operational +V3 ENT V –V3 Hubble would be successfully serviced and repaired four additional times. In Feb- SECTION S– S support provided by the MOU. Within about a year, the full contin- LINES gent of 15 ESA scientists and engineers was established at STScI. ruary 1997, during Servicing Mission 2, astronauts replaced the Goddard High Reso- URGE P ANDHOLD

H lution Spectrograph and the Faint Object Spectrograph with improved instruments,

23 22 21 20 After some delays, Hubble’s launch was scheduled for Octo- SI OARD STRAPS ERMINAL ROUNDING B +V2 T G HOWN QUIPMENT S ber 1986. But on January 28, 1986, the Space Shuttle Challenger the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) and the Space OT N OTA E OTA 11.02 24 exploded just over a minute into its flight. Shuttle flights ceased Telescope Imaging Spectrograph (STIS). In December 1999, as part of Servicing Mis- sion 3A, they replaced a transmitter, all six gyroscopes, and one of three Fine Guid- H G F E D C B A for two years. The telescope was completed, and went through thermal vacuum testing and integration with the ground system. ance Sensors, which allow fine pointing and keep Hubble stable during operations. 4 Hubble: Current Performance and Future Expectations Hubble: Current Performance and Future Expectations 5

Fig. A.1.2. Hubble’s new im- A.2. The Present: Hubble Observatory and Science Instruments proved optics (right) probe the A.2.1. Hubble Observatory: Servicing Mission 4 core of the distant galaxy M100. To the left, the original image Servicing Mission 4 (SM4) was carried out by astronauts flying on Space Shuttle taken with the aberrated optics. Atlantis beginning on May 11, 2009 (Figs. A.2.1.1vv, A.2.1.2). This mission — with five spacewalks — was the most complex and challenging of all the missions with three new instruments to be installed, two instruments to be repaired, and the re- placement of all the gyros and batteries, as well as the late addition to the manifest of the SI C&DH replacement. SM4 was a resounding success with all scheduled tasks accomplished. Hubble is now effectively a brand new observatory and more powerful than ever. The three new scientific instruments that were installed during SM4 were Wide Field Camera 3 (WFC3) in place of WFPC2, the Cosmic Origins Spectrograph (COS) that took the place of COSTAR, and a replacement for Fine Guidance Sensor 2 Servicing Mission 3B occurred in February 2002, when astronauts added the (FGS2). WFC3 offers new panchromatic (200–1700 nm) imaging capabilities with Advanced Camera for Surveys (ACS), the first new instrument to be installed order(s) of magnitude sensitivity gains over previous instruments at UV and near- in Hubble since 1997. ACS doubled Hubble’s field of view, using a much more IR wavelengths (Fig. A.2.1.3). COS has ultraviolet (UV: 90–320 nm) point source sensitive detector than WFPC2, improving the discovery efficiency by a factor sensitivity more than an order of magnitude greater than that of previous spectro- graphs on Hubble (Fig. A.2.1.4.). Fig. A.2.1.1. A beautiful launch of 10. for SM4. Hubble’s next servicing mission was scheduled for 2006. But on February 1, 2003, The astronauts also accomplished a feat never envisioned by the telescope the Space Shuttle Columbia, returning from a research mission, broke apart while creators — on-site repairs for two instruments: the Advanced Camera for Surveys re-entering Earth’s atmosphere. Shuttles were grounded. Then-NASA Administrator (ACS) and the Space Telescope Imaging Spectrograph (STIS). Both had stopped Sean O’Keefe called the Hubble mission off, citing the safety guidelines that had working, ACS after an electrical short in 2007, and STIS after a power failure in 2004. been developed following the Columbia tragedy. The next NASA Administrator, To perform the repairs, astronauts had to access the interior of the instruments, Mike Griffin, revisited the cancellation upon his appointment in 2005, and expressed support for another mission. On October 31, 2006, he announced that Hubble would be serviced again. The mission was scheduled for October 2008, but a failure of the “A” side of the Science Instrument Command and Data Handling (SI C&DH) unit less than three weeks before launch forced a six-month delay. These electronics command the instruments and control the flow of data to the ground. With only the redundant side “B” operational, this meant that there was no backup to this critical part of Hubble. The launch was therefore delayed to give engineers time to prepare the spare SI C&DH for inclusion in the servicing mission.

Fig. A.2.1.2. STS-125 crew portrait: From left: Mike Massimino, Greg Johnson, Scott Altman, Megan McArthur, John Grunsfeld, Andrew Feustel, and Mike Good. 6 Hubble: Current Performance and Future Expectations Hubble: Current Performance and Future Expectations 7

HST Discovery Space Table A.2.1: Observatory Status Overview 10 System Performance Summary Status / Details ACS WFC WFC3/IR Science Instruments • WFC3 performance is excellent • COS sensitivity decline is 5–10% per year WFC3/UVIS • COS FUV detector sensitivity is degrading, but remains high • Performance monitored monthly • ACS nominal/repaired (single-string WFC and SBC, no HRC) • Anomaly Review Board report issued April 2011 1 • STIS nominal/repaired (single-string) • Spectrum has been moved on detector to restore sensitivity UV/Optical Near-IR • NICMOS is currently safed, warm • Procedures to purge NCS are available if needed Discovery Discovery Space Space Electrical Power System • Solar Array Drive Mechanism total travel has exceeded life test • System-level state of charge is excellent (>500 Ah) • No evidence of deterioration 0.1 WFPC2 • Solar array performance is as expected • Solar array slew minimization strategy continues Data Management System • Payload computer experienced sixth CU/SDF lock-up events since • SSM computer and SI C&DH are operating nominally SM4 on 2 June 2012 ACS HRC NICMOS • Solid-state recorder performing well with only rare, • Cause understood; proven response plan in place; ACS SBC temporary lock-ups no hardware concerns 0.01

Discovery Efficiency (Throughput = Area) (Throughput = Discovery Efficiency Communications Fig. A.2.1.3. Discovery space 0.1 0.2 0.4 0.6 0.81 1 2 • MAT usage reduced to extend life • Multiple access transponders (MATs) are nominal • Coherent mode enables automation of HST tracking improvement of WFC3 in the • Antennae performance is nominal UV/IR with respect to other Wavelength (μm) cameras on Hubble. Pointing Control System • All gyros switched to secondary heater controllers to mitigate HST spectroscopic discovery potential • 2 of 6 gyros are experiencing bias shifts bias shifts/changes • Reaction wheel performance is nominal • 3 of 6 gyros are powered and in the control loop –15.5 • FGS-1R is functioning well • G3 (off) removed from control loop in Mar 2011 • FGS-2R2 is functioning well • G4 (on) experienced temporary motor current anomaly Sept 2011; rotor restriction suspected • FGS-3 bearing performance degraded; higher torques required • FGS-3 is used sparingly to preserve bearings –15.0 • Rate of degradation has slowed; life extended

) COS G130M –1 COS G160M Thermal Blankets • Thermal performance of equipment bays with New Outer Blanket Å COS G225M • Condition of multi-layer insulation observed during SM4 Layers tracks predictions well –1 –14.5 COS G185M COS G285M was better than expected; slow degradation continuing • Science Data Formatter temperature reduction strategy increases

sec • NOBLs installed on Bays 5, 7, and 8 during SM4 scheduling flexibility and thermal margin

–2 –14.0

STIS E230M+0.2x0.2 aperture –13.5 improved ones. Astronauts installed six new gyroscopes, which are used to point the telescope, and a Fine Guidance Sensor, which locks onto stars as part of the logFlux (erg cm logFlux (erg –13.0 pointing system. They covered key Hubble equipment bays with insulating panels STIS E140M+0.2x0.2 aperture — the New Outer Blanket Layers — to replace protective blankets that had broken –12.5 down over the course of their long exposure to the harsh conditions of space. They 120 160 200 240 280 320 also installed a new device, the Soft Capture Mechanism. This simple device will Fig. A.2.4. In-flight allow a robotic spacecraft to attach itself to Hubble someday, once the telescope sensitivities for the COS Wavelength (nm) is at the end of its life, and guide it through its descent into Earth’s atmosphere. gratings compared with STIS. Hubble is now a healthy, vital observatory operating at peak performance. switch out components, and reroute power. The successful completion of this task, Table A.2.1 provides a synopsis of the health and status of major components of the along with the addition of the two new instruments, gave Hubble a full complement observatory. Successful SM4 installation of advanced technology instruments for all of six functioning instruments for its future observations. areas of Hubble research, replacement of a Fine Guidance Sensor (FGS) and all six Since SM4 is expected to be the last astronaut mission to Hubble, one of the gyros, and equipment bay thermal blanket upgrades extend the long-term scientific goals was to reinforce and reinvigorate the telescope’s basic spacecraft systems. viability of the observatory, that is expected to provide at least another seven years Astronauts replaced all of Hubble’s batteries, which were 19 years old, with new, of unsurpassed scientific data, and could well last until 2020. 8 Hubble: Current Performance and Future Expectations Hubble: Current Performance and Future Expectations 9

A.2.2. Science Instruments Fig. A.2.1.1. Hubble science Hubble now has six science instruments offering a rich set of observing capabilities instruments: A, WFC3; B, ACS; at UV, optical, and near-IR wavelengths. All, with the exception of NICMOS, are C, NICMOS; D, FGS; E, COS; available for use. NICMOS is presently offline due to impurities in the NICMOS F, STIS. Cooling System (NCS) that prevent NICMOS from reaching its nominal operating temperature of 77 K. Procedures for purging the NCS and restarting NICMOS are available if sufficient science demand arises. Hubble’s new and repaired science instruments are in excellent condition and performing well (see Table A.2.1). Each instrument has many observing modes resulting from possible combinations of optics, filters, gratings, slits, and detectors. Table A.2.2 contains a summary of key instrument properties. Post-SM4 ACS and STIS performance is similar to that observed prior to SM4. WFC3 sensitivity, stability, and photometric accuracy meet or exceed pre-launsch expectations at both visible and IR wavelengths. COS sensitivity at far-UV wavelengths is excellent, but is declining a bit faster than expected (~5–10% per year versus ~2–4% per year). The COS detector has also experienced gain sag, as expected after several years of use. In the next two years, the algorithm will be adapted for use with WFC3/UVIS A new spectrum location on the detector has been adopted in July 2012 to restore data. lost sensitivity; several additional locations are available. • Development of a spatial scanning mode for WFC3 in 2011, which enables the Recent calibration and operation initiatives are enhancing the science potential light of astronomical objects to be trailed across the IR or UVIS detectors dur- of these instruments: ing exposures. This capability opens up possibilities for very high S/N photom- • A new post-observation algorithm to mitigate ACS/WFC charge transfer losses etry and astrometry, as well as observations of objects that would have been resulting from radiation damage of its CCDs. This breakthrough effectively too bright to observe in a conventional manner. For example, the WFC3 team is rolls back the clock on detector aging, enhances the science value of the using this mode to tie Vega directly into the HST infrared photometric standard data (deeper observations, less background, more accurate photometry/ system. In 2013 this capability may be expanded to ACS and STIS. astrometry), and facilitates comparisons of data obtained at different epochs. • Support of on-chip charge injection for WFC3/UVIS in 2011 and 2012, which The algorithm has been refined and implemented in the data pipeline in 2012. mitigates charge transfer losses. While not yet in heavy demand, this capability is now proven and available for observers to use when their science requires mitigation of these losses in the coming years. Table A.2.2: HST Science Instruments • Implementation of new COS grating settings that open access to wavelengths Instrument Channel (nm) Details FOV below 115 nm at high resolution in 2011–2012. Hubble is the only observatory ACS SBC 115–170λ 6 filters; 2 prisms (R~100; 115–180 nm) 35” X 31” that can spectroscopically observe astronomical objects in the 90- to 115-nm

WFC 370–1100 36 filters; 1 grism (R~100; 550–1050 nm) 202” X 202” wavelength range. COS FUV 90–200 R~3k; R~19k 2.5“ circle • Investigation and identification of new spectral locations on the COS FUV de- NUV 170–320 R~3k; R~20k; full-band imaging 2.5“ circle tector. Four new settings are possible, with a new position fully characterized FGS-1R —— 400–700 4 filters; photometry; astrometry ~69 sq. arcmin in 2012. This new setting will require ongoing calibration in 2013–2014 to man- NICMOS NIC1 800–1800 19 filters; polarimetry 11” X 11” age sensitivity and gain sag, along with preparations for adoption of a subse- NIC2 800–2450 19 filters; polarimetry; coronagraphy 19” X 19” quent (second) position change expected to occur by about 2015. NIC3 800–2300 16 filters; 3 grisms (R~200; 800–2500 nm) 51” X 51” STIS FUV 115–175 3 filters; R~1k; R~15k; R~45k; R~114k 25” X 25” • Development of WFC3 IR persistence maps, which can be used by observers NUV 170–320 6 filters; R~500; R~20k; R~30k; R~114k; prism 25” X 25” to remove residual effects of previous IR exposures on their science images. CCD 200–1030 3 filters; R~1k; R~8k; coronographic fingers 52” X 52” Experience gained now and in the coming years will be incorporated into the WFC3 UVIS 200–1000 62 filters; 1 grism (R~70; 190–450 nm) 162” X 162” IR 800–1700 15 filters; 2 grisms (R~210; 800–1150 nm and R~30; 1075–1700 nm) 123” X 136” strategy for dealing with IR persistence in the JWST detectors. NICMOS is currently dormant and not being used for science observations.

10 Hubble: Current Performance and Future Expectations Hubble: Current Performance and Future Expectations 11

A.3. Hubble Science after Servicing Mission 4 early galaxies formed. Although not the most distant galaxy, it is among the A.3.1. Highlights of Recent Exciting Discoveries faintest to be observed with such clarity because it is lensed. In April 2012, the Hubble Space Telescope celebrated its 22nd anniversary in • Reduction in the Hubble constant uncertainty to 3.3% through WFC3 observations space, more powerful than ever. Looking back on the past two decades, there are of Cepheids in galaxies containing Type Ia SNe. This improvement rules out remarkable discoveries and achievements, some expected and some beyond the an enormous bubble of nearby empty space as an alternative for dark energy. dreams of the telescope’s designers. Quantifying the expansion rate of the universe, • COS observations of Ne VIII and other highly ionized elements in the IGM determining the properties of the intergalactic medium, detecting black holes at and galaxy halos, providing new insight into ~106 K gas that was previously the centers of galaxies, and producing ultra-deep color magnitude diagrams of observable spectroscopically only at X-ray wavelengths. stellar populations were early key drivers for the mission, but the discovery of • COS observations demonstrating a strong correlation between star-formation the accelerating universe, observations of protoplanetary disks, identification and highly ionized oxygen in galactic halos. Surprisingly, these galaxies con- of gamma-ray burst sources, witnessing collisions in the solar system, and tain as much mass in heavy metals alone as is in their entire ISM. observations of exoplanets and their atmospheres were all unanticipated. Looking • WFC3 discovery of Pluto’s fourth and fifth moons, P4 and P5, during sup- forward, with a renewed Hubble three years into its post-SM4 prime mission and porting observations for NASA’s New Horizons mission. This follows earlier at its scientific peak, we expect many more discoveries ahead. Hubble discoveries of two moons, Nix and Hydra, with ACS in 2005. At least Having a diverse suite of instrumentation and a broad science program, one more moon may be present. Hubble has been well-positioned to address “Cosmic Vision’s” key questions: • STIS measurement of the transmission spectrum of exoplanet HD 189733b at What are the conditions for planet formation and the emergence of life? How optical wavelengths, lending support to the idea that high altitude haze is a did the Universe originate and what is it made of? dominant atmospheric feature of the planet. Hubble’s current science portfolio encompasses a wide variety of program siz- • COS dating of the helium reionization era to a time when the universe was es, ranging from ~1 hour to ~500 hours of on-target time, and program types (e.g., between 2 and 2.4 billion years old. At this time, only AGNs fueled by galaxy parallel observations, snapshots, multi-cycle observations, treasury programs, tar- mergers produced the copious amounts of UV radiation necessary to ionize gets of opportunity, Director’s discretionary observations, archival research, and helium. theoretical investigations). Hubble’s longevity has provided opportunities to advance entire branches • COS detections of heavy elements in the atmospheres of transiting exoplan- of astronomy, witness rare events, and dramatically expand discovery space. Its ets HD 209458b and WASP-12b, showing that their atmospheres are being complement of instruments provides multiple approaches to tackling a broad thermally inflated and swept away by the parent stars. range of science. • WFC3/UVIS images of a suspected collision between a small (10- to 15-foot) As a collective international endeavor involving more than 5000 scientists rock and asteroid Scheila, leaving an unusual “X”-shaped debris pattern that worldwide, Hubble remains at the forefront of observational astronomy. only Hubble could resolve. Hubble’s new and repaired instruments have fulfilled their promise to deliver • STIS mapping of high ionization plasma in the inner arc second of Eta Carina, important and exciting science results (see, e.g., Fig. A.3.1.3). More than 335 pa- the first observations that fully image the extended wind-wind interaction pers based on COS or WFC3 data have appeared in the literature already, and this region of this massive colliding wind binary system. number is increasing rapidly as early studies with these instruments come to frui- • FGS discovery of the smallest Kuiper belt object ever detected in visible light. tion. Science highlights from the past 2–3 years include: At only 3200 feet across, this object is 50 times smaller than the smallest • WFC3 discovery of the most distant object ever observed, a compact galaxy Kuiper belt object previously observed. of blue stars 13.1 billion light years away, suggesting that star-formation in- Because of the two-decade lifetime of the mission, long baseline temporal creased rapidly when the universe was 480 million years old (z ≈ 10). This studies have become very relevant: extends the cosmic frontiers established by WFC3 discoveries of z = 7–8 gal- • Time-lapse movies of supersonic jets of young stars reveal never before seen axies just after SM4 (Fig. A.3.1.3). details of how the jets interact with surrounding interstellar material. These • ACS and WFC3 observations of a lensed galaxy whose stars formed when movies help to test and refine computer simulations of these complex processes. the universe was only 200 million years old, challenging theories about how • New analysis techniques applied to images taken in 1998 of HR 8799, a mas- 12 Hubble: Current Performance and Future Expectations Hubble: Current Performance and Future Expectations 13

Fig. A.3.1.3. This is the deepest The MCT programs arise from a combination of Director’s Discretionary Time image of the Universe ever taken and time drawn from the pool of orbits normally set aside for large observing in near-infrared light by the programs. All MCT data are non-proprietary. These programs, which are now Hubble Space Telescope. The in their second year, require significant planning and scheduling support. They faintest and reddest objects (left use ACS and WFC3 in parallel to maximize the amount of science information inset) in the image are galaxies returned during each observation and are among the most challenging programs that correspond to “look-back ever undertaken by Hubble. They have already spawned more than 40 science times” of approximately 12.9 papers and produced more than 500 GB of high-level science products (HLSP) for to 13.1 billion years ago. No galaxies have been seen before at archival researchers. The download of >11 TB of these products by 729 distinct IP such early epochs. addresses attests to the strong demand for these products by the community. A.3.2.1. Panchromatic Hubble Andromeda Treasury Survey (PHAT) This 828-orbit UV/optical/near-IR survey of the northeast quadrant of M31 (PI: J. Dalcanton) adds the Andromeda galaxy to the Milky Way and Magellanic Clouds as a fundamental calibrator of stellar evolution and star-formation processes in galaxies. HST imaging in 6 filters resolves the galaxy into millions of stars, all with common distances and foreground extinctions. Stellar photometry provides effec- sive star with 4 known planets, find 3 of the 4 planets previously undetected tive temperatures for O through M stars, while simultaneously mapping extinc- in the original NICMOS data. Similar analyses of other stars may yield new tion. Primary science drivers exoplanet detections; an archival study of over 400 stars is in progress. include characterizing high- • Precise measurements of distant lensed galaxies in ACS observations of Abell mass (3–30 M ) variations in Optical, HST Optical, ground 1689 show that the dark matter profile of the cluster is highly centrally con- the stellar initial⊙ mass func- centrated, suggesting the cluster formed earlier than expected and raising new tion as a function of star questions about dark energy. formation rate and metallic- • Analyses of ACS data have refined estimates of galaxy merger rates over the ity, mapping the spatially re- past 8–9 billion years, a first step to seeing if merger rates are coupled to star- solved star formation history formation rates in galaxies of different types. This work is testing cosmological of M31 on 50 pc scales, and and galaxy formation simulations. measuring the mass function 120 and age distribution of stellar New Hubble • An analysis of stellar flares in data obtained for a microlensing-based exoplanet clusters clusters with a range of me- search shows that variable red dwarf stars with star-spots are 1,000 times more 100 Previously tallicities (Fig. A.3.2.1). The known likely to flare than their non-variable counterparts. This result has (dire) impli- data also contain informa- clusters cations for exo-life on planets around such stars. 80 tion central to understanding A.3.2. Maximizing Hubble’s Scientific Return: The Multi Cycle Treasury the coupling of star forma- 60 Fig. A.3.2.1. Hubble’s exquisite Programs tion and the interstellar me- resolution and sensitivity enable N Clusters To tackle key scientific questions that cannot be fully addressed by the standard dium, and the environments 40 studies of objects that cannot be time allocation process, Hubble is presently devoting approximately one quarter of of transient or variable ob- detected with other telescopes. The PHAT program has identified its observing time to four visionary Multi-Cycle Treasury (MCT) programs. When jects (e.g., novae, SNe, vari- 20 the MCT observations draw to a close in Cycle 20 (2013), they will have mapped able stars, X-ray sources). hundreds of low-luminosity the constituent populations of the nearest spiral galaxy, constrained the nature of Highlights to date include: stellar clusters in M31 for the 0 first time and is well on its way dark energy by searching for supernovae at redshifts z > 1.5, traced galaxy assem- • Over one third of a 14 16 18 20 22 24 to producing the most complete bly from z ~1 to z > 6, used massive clusters to test the Lambda Cold Dark Matter square degree in M31 has m cluster sample for any spiral (ΛCDM) model, and probed star formation in strongly lensed galaxies at z > 7. F475W been imaged, extending galaxy. 14 Hubble: Current Performance and Future Expectations Hubble: Current Performance and Future Expectations 15

from the bulge to the outermost star forming disk. With a current library of bursts in massive galaxies are not related Fig. A.3.2.2.1. Hubble reveals over 82 million stars, the survey is on track (>60% of the way already) to match to central black hole growth. galactic structure that cannot the total number of stars in the SDSS survey, when complete. • Super-high-star-forming galaxies at z ~ 2 be resolved by other telescopes. • There exists a wealth of unusual stars associated with the inner parts of the tend to be associated with galaxies that The CANDELS program metal-rich bulge, including extremely hot evolved stars that are likely linked are irregular, interacting, or merging is quantifying the near-IR to the source of the “UV excess” seen in elliptical galaxies, and an unexpected (Fig. A.3.2.2.1). This repeats the well- morphology of z ~ 2 ULIRGs population of cool IR-luminous stars with highly unusual colors that cannot be known pattern seen at lower redshifts in identified by Herschel to determine what processes fuel fit with any existing atmospheric models. At the other extreme, there is also which ultra-luminous infrared galaxies starbursts in these ultraluminous evidence of ancient metal-poor stars in the bulge. (ULIRGs) are associated with mergers. It galaxies. • Cold gas has been mapped on ~5 kpc scales by generating large-area dust appears that extremely high star-forma- extinction maps with a resolution of 30 pc using near-IR observations of RGB tion rates are associated with external, stars. Dense structures of young, hot stars emerge from the network of cold gas interacting triggers at all redshifts. traced by dust maps. Hundreds of young stellar clusters are identifiable. • A strong correlation between rest-frame UV spectral slope and stellar mass is evident for star-forming galaxies at all redshifts, with more massive galaxies having Creating the M31 mosaic is painstaking work relying upon exquisite instru- redder colors. This is attributed to reddening by dust, implying high metallicities ment calibration. The PHAT team is taking astrometric and photometric calibra- in massive galaxies even at high redshift. The data extend the well-known mass- tions to new levels, well beyond what has been needed in the past. Some of this metallicity relation for galaxies to z ~ 5, and supply new insight into how galaxies new information is being incorporated into the standard ACS and WFC3 data pipe- synthesize heavy elements. lines. These calibrations set the standard for future programs pushing the limits of Hubble’s imaging capabilities. A.3.2.3. Cluster Lensing and Supernova Survey with Hubble (CLASH) The 524-orbit CLASH program (PI: M. Postman) is studying the most massive A.3.2.2. Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) objects in the universe. Galaxy clusters represent important signposts in the story The 908-orbit CANDELS project (PIs: S. Faber/H. Ferguson) is documenting of structure evolution. They are also the ultimate telescopic lenses, bringing gravi- galactic evolution from z = 1.5 to 8 by imaging more than 250,000 galaxies with tationally lensed galaxies from the earliest epochs into view for detailed study (Fig. WFC3/IR and ACS. Five premier multi-wavelength regions, selected from within A.3.2.3.1). This program takes full advantage of ACS and WFC3 to deliver deep the Spitzer Extended Deep Survey with complementary Spitzer IRAC data, yield 16-filter images of 25 clusters chosen to be free of lensing bias and to span a wide statistically robust samples of galaxies down to 109 M and out to z ~ 8. The pro- range of mass and redshift (0.15 < z < 0.9). By gram incorporates a two-tiered strategy using a “wide”⊙ component (2 orbits deep combining strong and weak lensing, defini- over ~0.2 sq. degrees) and a “deep” component (12 orbits deep over ~0.04 sq. tive mass profiles are being derived for com- degrees). Combining these with ultra-deep imaging from the Ultra Deep Field pro- parison to predictions of the standard ΛCDM gram yields a three-tiered strategy for efficient sampling of both rare/bright and model. Detailed maps of internal structure faint/common objects. Science highlights to date include: will be enabled by ~1,000 new multiply-im- • Detections of numerous emission-line galaxies at z ~ 1.7 point to ~108 M dwarf aged lensed sources to m =26, all with pre- galaxies undergoing extreme starbursts with typical timescales of only ~15⊙ mil- AB cise (2% x (1+z)) photometric redshift mea- lion years. The resulting gaseous outflows may be strong enough to evacuate surements. Science highlights to date include: dark matter from the centers of low-mass galaxies, and the galaxies are suffi- • Observations of cluster MACS J1206-08 ciently numerous to suggest that many, even most, stars in present-day dwarfs have identified 47 new lensed images of were formed in strong, short-lived bursts at z > 1. 12 sources at 1 ≤ z ≤ 5.5. The derived • AGN host galaxies at z ~ 2 have morphologies comparable to non-AGN sys- Einstein radius (θ ≈ 28’’) and inner clus- tems at that redshift, with no evidence for a preponderance of major merg- E ter mass of (1.34±0.15)x1014 M place it ers or strongly interacting systems, contradicting the predictions of standard ◉ at the high end of the cluster mass func- models. This suggests that the mechanism that triggers black hole growth is tion, implying that a stringent test of the more related to internal structure than external interactions. Perhaps star- Fig. A.3.2.3.1. Abell 383 ΛCDM paradigm may be possible if other galaxy cluster. 16 Hubble: Current Performance and Future Expectations Hubble: Current Performance and Future Expectations 17

Fig. A.3.2.3.2. A high-redshift clusters at this redshift show similarly high “The discovery of the accelerating expansion of the Universe is a milestone lensed galaxy behind cluster masses. for cosmology, as significant as the discovery of the minute temperature varia- tions in the Cosmic Microwave Background (CMB) radiation with the COBE MS 1358.4+6245 observed by • Observations of cluster MACS J0329-02 satellite.... Although not as evident at the time of the discovery, later studies of Hubble. The 50-pc resolution in contain the first detection of a quadruply SNe beyond z = 1 [Riess et al. 2004], from the time when the Universe was much this image is equivalent to the lensed galaxy at z ~6. denser and ΩM dominated, indicate that at that early epoch, gravity did slow resolution of a 20m space tele- • The use of clusters as lenses reveals the down the expansion as predicted by cosmological models. Repulsion only set scope for a non-lensed structure of high-redshift galaxies on scales in when the Universe was about half its present age.” z=5 galaxy. of <200 pc (Fig. A.3.2.3.1 ). Hubble is the only observatory capable of making critical measurements of supernovae to constrain the properties of dark energy at redshifts beyond z ~ 1. By extending even further to z > 1.5, Hubble is testing the constancy of dark energy A.3.2.4. Dark Energy and MCT Supernova Search with time and probing whether progenitor evolution influences the use of SNe Ia as This 250-orbit supernova search (PI: A. Riess) identifies and characterizes su- standard candles (Fig. A.3.2.4.1). Highlights of this MCT program to date include: pernovae (SNe) found in the CANDELS and CLASH fields by differencing the multi- • A recent Type Ia supernova found at z = 1.55 (“SN Primo”) holds the record epoch images taken in these surveys. When supernovae are found, light curves as the highest-redshift spectroscopically-confirmed SN Ia and demonstrates and grism spectra of the best Type Ia candidates are obtained to determine their Hubble’s ability to find and characterize high-z SNe in the discovery space distances and redshifts, with an ambitious goal of finding as many at z > 1 as opened up with WFC3 (see Fig. A.2.1.3). possible. Studies using SNe Ia as standard candles have shown that the expansion • Discovery of 43 new SNe Ia (29 CANDELS, 14 CLASH), including 6 at z > 1.5, velocity has been increasing for the last several billion years — an incredible and doubles the sample size previously established by the GOODS surveys and completely unexpected result attributed to the vacuum energy (or “dark energy”) provides stronger constraints on the rates of SNe Ia. of space. Hubble observations of SNe Ia are playing a prominent and unique role • Methods for galaxy host light removal in WFC3 grism spectra of 5 SNe allow for in quantifying the acceleration. The 2011 Nobel Prize committee recognized this a robust determination of the uncertainty in the derived SNe spectra, thereby in their selection of last year’s prize winners. Fig. A.3.2.4.1. demonstrating the utility of WFC3 for accurate identification of SN spectral Supernova progenitor evolution features. Age of the Universe (Gyr)

13 9 6 4 3

Progenitor evolution: tpost–MS = 2.5 Gyr 0.6 init. prog. mass > 6.7 M

⊙ 0.4 Variable Dark Energy: SN Primo ∆CDM w = w + w (1+a) 0 a >3.5 ∆w = 0.8 t = 0.2 a post–MS – μ >2.5 ∆w0 = 0.1 0.4 Gyr

observed 0.0 μ >1.5 >1.6 >1.7 M ⊙ –0.2 SDSS SNLS HST+ACS HST+WFC3

–0.4 0.0 0.5 1.0 1.5 2.0 2.5

Redshift (z) 18 Hubble: Current Performance and Future Expectations Hubble: Current Performance and Future Expectations 19

A.4. The Future: Hubble Observatory and Science Instrument A.4.2. Hubble Observatory Lifetime Predictions Performance Expectations A.4.2.1. Fine Guidance Sensors A.4.1. Science Instrument Lifetime Predictions Hubble has three fully functioning FGSs available as guiders, but no more than two are used for pointing control at any given time. Installation of FGS-2R2 during Hubble’s science instruments have dual-string electronics for redundancy and SM4 leads to an expected operational lifetime of 11–14 years for the FGS comple- longevity. All past instrument failures, with the exception of a thermal short in the ment. FGS-3 operations are managed to preserve the life of the degraded bearings, NICMOS dewar in its first years of use, occurred in electronics hardware. SM4 pro- and FGS-1R and FGS-2R2 are operated in such a way as to mitigate the onset of the vided Hubble with three independent electronics strings in the most-used imagers condition present in FGS-3. In the event of multiple FGS failures, single FGS guiding (two for WFC3, one for the repaired ACS), as well as three strings in the spectro- is possible. FGS-1R also serves as an astrometer. graphs (two for COS, one for the repaired STIS). A.4.2.2. Gyros Probabilistic lifetimes of Hubble’s current instruments have been assessed using the actual failure history of its previous instruments. Prior to SM4, previous individual Hubble uses extremely accurate gas-bearing gyros to sense and report small electronics strings operated for a total of 373 months with 7 electrical failures, for an movements of the telescope to its onboard pointing control system. These gyros are average mean time to failure of 53.3 months per string. Figure A.4.1.1 shows the prob- subject to failure through prolonged use. In response to past failures, contingency ability of the two cameras, ACS (single-string) and WFC3 (dual-string), being opera- observing modes have been developed involving only one or two gyros to use in tional as a function of time, as well as the probability that both cameras and neither place of the standard three-gyro observing mode. Use of these reduced-gyro modes camera are working. WFC3 should last substantially longer than ACS. The probability leads to only a small degradation in observing efficiency (from about 48–43% on of two cameras operating is dominated by the ACS single-string lifetime, while the average); however, the observing flexibility (that is, at what times during the year a probability that neither camera is working is dominated by the WFC3 dual-string life- given object can be observed) is reduced to about half of that in three-gyro mode. time. The 50% probability point of neither camera working occurs 8.7 years after SM4 Astronauts replaced all six gyros during SM4. Three are currently powered and (i.e., early 2018). One can substitute STIS for ACS (single-string) and COS for WFC3 three remain in reserve. Two have shown susceptibility to changes in bus voltage (dual-string) in order to get equivalent predictions for the spectrographs. across the day/night terminator. One of those gyros was placed in reserve in March The expected 50% probability lifetime just for dual-string instruments is 89 2011 to be used at a later point in the mission. To minimize potential impact to months, or 7.4 years. There is a 70% probability of having at least one (COS or WFC3) other gyros, all have been switched to the high bandwidth secondary heater con- available at the time of the JWST launch in October 2018. These estimates do not troller to mitigate the effects at the terminator. Barring exceptional circumstanc- take into account that electronics on both COS and WFC3 were upgraded prior to es, observations will continue in three-gyro mode until it is necessary to enter a SM4 to replace parts implicated in earlier instrument failures; we fully expect both reduced-gyro mode. The mean time until that transition is expected to be at least instruments to last longer than previous generation instruments. 4 more years (2016). It has been demonstrated that one-gyro mode performance is essentially the same as two-gyro mode, and therefore, reduced-gyro operations should be possible for more than 10 years. 1.0 A.4.2.3. Batteries 0.9 ACS WFC3 Although Hubble’s original batteries were still working well up to SM4, albeit at 0.8 No camera reduced charge capacity, astronauts replaced both NiH battery modules as a precau- 0.7 Both cameras 2 tionary measure. Performance and the state of electrical charge of the replaced units 0.6 are excellent (>500 Ah). They are not expected to be a life-limiting mission element. 0.5 Fig. A.4.1.1. Probability of A battery test bed has been maintained at the Marshall Space Flight Center since

Probability 0.4 the ACS and WFC3 imaging launch to facilitate analysis of this critical subsystem. 0.3 cameras being operational 0.2 A.4.2.4. Other Subsystems as a function of time. One 0.1 Hubble has a very robust and redundant spacecraft bus and subsystem set. Re- can replace ACS with STIS 0 dundancy is provided either by having multiple units, or multiple electronics strings (single string) and WFC3 with 0 10 20 30 40 50 60 70 80 90 100 110 120 within individual units, or both. Many subsystems have functioned throughout the COS (dual string) to get the life of the mission on their primary electronics strings. The probability of not suffer- equivalent estimates for Months after SM4 HST’s spectrographs. ing a random failure, based on observed performance to date, is monitored by the 20 Hubble: Current Performance and Future Expectations Hubble: Current Performance and Future Expectations 21

Table A.4.2.4.1: HST Subsystem Non-Failure Probabilities GSFC engineering team, and Table A.4.3.1: HST Life Extension Initiatives Reliability was reviewed in August 2011 Life Extension Initiative Description and Benefit Status Hardware # Units (probability of no failures for the period 2011–2016. Of Attitude control using 2 gyros + another sensor (MSS, FHSTs, FGS). Quality science prior to Aug 2016) 2-Gyro Science Mode Ready for use the 50+ subsystems evalu- with only 2 gyros. Used in 2005-2009 prior to SM4. Fine Guidance Sensor and 3 46% ated, most have probabilities Fine Guidance Electronics Attitude control with 1 gyro + combination of MSS, CSS, FHSTs, FGS, and B-field of 90% or higher of not suf- 1-Gyro Science Mode Ready for use Solid State Recorder 2 58% model. Performance identical to 2-gyro mode. fering a single failure before TFC, Communication Line, HST Data Management System Prepare in advance for a full S/C side switch; used in 2008 for SI C&DH side switch. 1* 61% Ready for use TIM, DIU5, and CU/SDF mid-2016. Subsystems with Side Switch Shorter recovery; quicker return to science. less than 80% reliability are Memory Module 8 66% Advanced Develop NSSC-I FSW recovery process needed for possible memory module failure. Reaction Wheel Assembly 4 72% listed in Table A.4.2.4.1, and NSSC-I Memory Module Failure Procedure Shorter recovery; quicker return to science. Fixed Head Star Tracker 3 74% all of these have adequate Ready Advanced MA Transponder 2 77% redundancy to guard against Communication Assets Hybrid Procedures for contingency communications, extending life of critical components Procedure Solar Array Drive failure. Only 4 subsystems Modes and reducing recovery time. 2 79% Ready Electronics have reliabilities of less than Kalman Filter Sun Point (KFSP) Sun point control law using combination of CSS, MSS, and any number of gyros. Remote Interface Unit 2* 80% Implemented 70%: the Fine Guidance Sen- Safe Mode Faster Sun capture. Aperture Door remains open. PSEA MCE 1* 80% sors and associated electron- Optimize FGS parameters, usage, and acquisition procedures. Maximizes FGS life FGS Maintenance & Optimization Implemented Risk of single failures in these systems is mitigated by having multiple ics (3-unit redundancy), the and improves acquisition success rate. units and/or internal 2-string redundancy (items marked with *). All Solid State Recorders (2 unit Power System Charging Optimize charging and operations to maximize battery life. Taper charge extends other subsystems have >80% reliability; most have >90% reliability. redundancy), a hardware Implemented Optimization NiH2 battery life and minimizes state-of-charge losses. string in the Data Manage- Fixed Head Star Tracker Shutter Reduce use of FHSTs to minimize FHST shutter cycles/wear, and ensure bright Implemented ment Unit (1 unit, 2-string redundancy), and the SI C&DH Memory Modules (8-unit Management object FHST protection. redundancy). Observatory operations should continue for many years, even in the S-Band Single Access Transmitter Use two SSATs in operations rather than only one. Longer services reduce SSAT Implemented event of single failures in these subsystems. Management cycles.

A.4.3. Mission Life Extension Activities Multi-Access Transponder (MAT) Reduce MAT cycles by 37%, maximizing concurrent scheduling and operations Implemented Cycle Reduction efficiency without adding risk to the spacecraft. Realizing that Hubble’s unique capabilities will not be reproduced by any existing Thermal Control of Equipment Asymmetric roll constraints before blankets installed during SM4. or planned astronomical research facility on Earth or in space for the foreseeable Implemented future, a Life Extension Initiatives (LEI) program had been established in 2004 Bays 5 and 8 Avoids solar heating and keeps bays/subsystems within thermal limits. Science Data Formatter Minimize post-SM4 Bay 10 temperature excursions and increase expected opera- to keep Hubble viable until SM4. That program continues today on a resources- Implemented available basis with the purpose of ensuring scientific efficacy past 2016, and a goal Temperature Mitigation tional life of Science Data Formatter. of providing at least a year of overlap with JWST operations (launch in late 2018). Reaction Wheel Speed Reduction Modify command generator to reduce maximum wheel speeds during maneuver, Implemented Table A.4.3.1 summarizes the accomplishments and status of current initiatives. During Slews reducing probability of RWA component failure. Not surprisingly, LEI activities focus on instruments and subsystems that exhibit Tune battery charge rate by reducing solar incidence angle variations. Solar Array Offset Management Implemented higher failure probabilities due to their age and failure history. Some of these initia- Battery charge improvement; replaced by taper charge use (see above). tives, such as reduced gyro operations, Multi-Access Transponder cycle reduction, SDF temperature mitigation, and reaction wheel speed reduction during slews, are Science Instrument Power Train Prepare for science instrument power train side switch; in use on orbit for ACS and Work in Prog- already implemented and reducing the risk and impact of failure. Initiatives cur- Side Switch STIS; COS and WFC3 planned. Shorter recovery; quicker return to science. ress Identify potential science mode configurations of the remaining viable assets within Work in Prog- rently being worked or planned have a common goal of restoring science capability Science Instrument Hybrid Modes quickly after a failure by reducing recovery times from weeks or months to days. ACS, STIS, WFC3, COS. Extends instrument lifetime. ress These include preparing for instrument or spacecraft electrical problems, identifying Reduced-Wheel Reduced-Gyro Robust safemode using magnetic torquers as actuators and CSS, MSS, and gyros Work in Prog- alternative communications options and impacts arising from transponder failures, Safemode as sensor input to KFSP in the event of reaction wheel loss. ress Science mode using 2 wheels and 3 gyros, with magnetic torquers in place of the and implementing new safe modes. A reduced-wheel reduced-gyro safemode is now Feasibility Study 2 Reaction Wheel Science Mode missing wheel, and CSS, MSS, and gyros as sensor input to Kalman Filter. Extends and Preparation available, which provides for satellite safing in the event of two successive reaction science mission if two wheels fail. 22 Hubble: Current Performance and Future Expectations Hubble: Current Performance and Future Expectations 23

wheel failures. Development of this mode lays the foundation for subsequent (but the Chandra Deep Field-South. The ACS observations reach limiting magnitudes

as yet unplanned) development of a two-wheel science mode in the future if Hubble (m AB ~ 29 in B, V, I, and z) corresponding to the brightest galaxies at z ~ 6–7. Re- experiences a reaction wheel failure. cent supplementary observations of comparable depth with the WFC3/IR channel in the Y, J, and H bands have pushed even further toward the edges of the observ- A.5. A Leap Forward: Future Scientific Initiatives able universe, resulting in the first candidate z ~ 10 galaxy. From an instrumentation standpoint, today’s Hubble is effectively a new tele- The early universe and first galaxies are a primary theme of the JWST science program. scope with greatly expanded capabilities and wavelength access. The oversubscrip- NIRCam has five times the sensitivity of WFC3/IR at near-infrared wavelengths, the same field tion rate remains very high (see Fig. B.1.2.1), and we expect significant cutting- of view, and 2.5 times the angular resolution. However, IR imaging alone is insufficient to edge science across a full range of science programs from planets to cosmology. unambiguously identify objects out to z ~ 10. High-redshift objects are generally identified as However, there are some areas of science, particularly those requiring very large “drop-outs” (objects that lack flux) in photometric passbands shorter than a particular wave- amounts of observing time (hundreds of orbits or more) that cannot be accom- length that corresponds to the (redshifted) Lyman break. Deep imaging data at UV-optical modated within the standard call for proposals, and yet can produce revolutionary wavelengths are necessary to exclude lower-redshift interlopers that would otherwise domi- results. Hubble is currently investing substantial resources in its Multi-Cycle Trea- nate high-redshift galaxy surveys. At present, shorter wavelength data of the required depth sury programs for this very reason. The nominal end date for these observations is necessary for studies with JWST exist only within the UDF, which does not include sufficient Cycle 20, but the data produced will provide an invaluable resource for community volume even at the highest redshift to provide a representative sample of the early universe research for many years to come. Starting in Cycle 21 (2014), additional steps will (Fig. A.5.1). Therefore, it is not possible to answer the fundamental question: “Is what we see be taken to ensure that Hubble’s legacy extends to the era of JWST and beyond by in the UDF typical of the high redshift universe?” targeting key areas requiring Hubble data: (1) An exploration of the early universe One can try to tackle the issue using cosmological models and assumptions will extend Hubble’s ultra-deep vision in many directions and pave the way for about the formation of the earliest galaxies, but this question can only be definitively JWST’s primary science program. (2) The creation of an Ultraviolet Astrophysics answered through direct observations. Galaxy number density and luminosity func- Legacy Program will take advantage of Hubble’s unique abilities to observe the tion estimates from small deep fields suffer from cosmic variance because galaxies ultraviolet universe now and build a fundamental archival resource for future as- are clustered. There are ~100 z = 6 I-dropout galaxies in the UDF, but the galaxy den- tronomical investigations. (3) The creation of an HST Source Catalog will provide sity estimates are accurate to only ~35%, not 10%, since cosmic variance, not Poisson a unique and uniform database of objects observed by Hubble over the entire sky. statistics, dominates the uncertainties. The two parallel UDF flanking fields reduce A.5.1. Ultra-Deep Fields the uncertainties, but those fields are not as deep as the primary UDF field and are Understanding galaxy formation has been a key goal in astronomy since the separated by only a few arc minutes. Additional well-separated ultra-deep fields are recognition of “island universes” at the dawn of the 20th century. The Hubble essential for clean, rigorous tests of the variance predicted by standard ΛCDM theory. Space Telescope pioneered the use of “deep fields” to A second UDF would reduce the uncertainty in the number density of I-dropout gal- investigate galaxies in the early universe, giving us axies at z = 6–20%, and when combined with additional parallel imaging data would new insights into the role of mergers in galaxy assem- bring the error down to 12%. bly, the evolution of galactic properties, and reioniza- Beyond z ~ 6, an accurate assessment requires more than one additional UDF tion of the intergalactic medium at early times. The since the number density of galaxies decreases. Additional areal coverage is es- Fig. A.5.1. A portion of the original Hubble Deep Field revealed unexpectedly sential to measuring the faint end of the luminosity function and evaluating the Hubble UDF observed with complex morphologies in high-redshift galaxies, high- contribution of redshift 6, 7, and 8 galaxies to the reionization of hydrogen. At z = the WFC3/IR channel in lighting the importance of mergers and the dynamic 10, the single galaxy in the UDF reported to date is clearly insufficient to estimate 2010. This deep view of the state of the early universe. Subsequent programs, in- reliable number densities. universe revealed the most cluding GOODS, COSMOS, GEMS and, most recent- Starting in Cycle 21, the STScI Director will devote discretionary observing time distant galaxy candidate ly, CANDELS, have built on those results, combining to produce another complete Hubble ultra-deep field, at both optical and near-IR (z ~ 10) ever seen, as well multi-wavelength data from space- and ground-based wavelengths at a location far away from the existing UDF, to address the issue of as a primordial population observatories to probe galaxy evolution in increasing cosmic variance and prepare the way for future JWST observations. This initiative of compact and ultra-blue detail out to redshifts z ~ 5. The deepest investigations will also include deep imaging data in two blue/optical filters (e.g., F435W, F606W) galaxies that had never of the early universe are those within the Hubble UDF, to start up to three additional supplementary ultra-deep community fields. We been seen before. lying in the GOODS/South field which is itself part of will consult with the community to identify optimal locations for the second and 24 Hubble: Current Performance and Future Expectations Hubble: Current Performance and Future Expectations 25

Fig. A.5.2.1. High-resolution will be given full opportunity to exploit these unique capabilities in Hubble’s final

observations of faint QSOs J1009+0713 zQSO = 0.456 years and to populate the archive with valuable datasets that can be mined both

are easily obtained with COS ) now and by future generations of researchers. –1 10 Target (H1 + OVI) Å

in only a few hours. This rich –2 Typically, the HST Time Allocation Committee (TAC) panels reviewing regular 8 (H1 + OVI) spectrum contains an abundance cm GO programs allocate 30–40% of available observations to investigations requiring –1 DLA + metals of information, including HI 6 UV observations. However, larger programs in recent years, particularly the MCT

and O VI absorption features ergs 4 LLS programs, have generally focused on investigations at longer wavelengths and there due to galaxy halos, a damped –15 10 has been little in the way of standard UV treasury programs to produce high-level

X 2 Lyman-alpha system (DLA), and science products for the community. 0 a Lyman Limit System (LLS). Flux ( A significant component of the ultra-deep field initiative described above will Archival data for hundreds of 1200 1300 1400 1500 1600 1700 depend on WFC3 imaging at UV wavelengths, and observing time will be dedicated QSO sight lines now exist. Wavelength (Å) to that effort from the Director’s discretionary time. However, the broad diversity of astronomy possible at UV wavelengths argues against consolidation of all UV legacy supplementary deep fields, and input will be sought on how ancillary science (e.g., initiatives within a single observing program. Rather, starting with the standard Type Ia SNe searches, COS absorption line studies, etc.) related to these fields can proposal call in Cycle 21, an Ultraviolet Astrophysics Legacy category of proposals be maximized. Once identified, the field centers will be publicized to maximize will be instituted whose primary purpose will be to produce archival products of the possibility of obtaining supplementary ground- and space-based data. The lasting value for future investigations requiring UV information. Merely obtaining new possibility of coordination with other major space observatories such as Herschel, data will not be a sufficient condition for such proposals to be approved. Successful XMM, and Spitzer is being explored. To the extent possible, observations will be proposals must identify and commit to producing tangible high-level science products made using WFC3 and ACS in parallel, approximately matching the depth of the for the archive. Such products might include fully reduced image mosaics, fully original UDF dataset, for a total of ~750–1000 orbits in Cycles 21–23. The data for extracted grism spectra, combinations of slit spectra stitched together across multiple these new community fields will be non-proprietary and, as with the HDF and wavelength settings, catalogs of ultraviolet properties (flux, morphology, spectral line UDF, STScI will produce and release high-level data products for the community identifications, etc.), or algorithms for extraction of information from fully calibrated to analyze. Moreover, the community will have an opportunity in the standard UV datasets (e.g., equivalent widths, column densities, etc.). Proposers may request new proposal call to propose additional observations in the supplementary fields as observations or use existing archival data in the creation of these products. Building the shorter wavelength data are collected. For example, large programs could be a deeper library of high-level UV science products on par with those already available proposed to add ~100–150 orbits/field of F775W I-band data to match the UDF or at longer wavelengths will increase both the near-term (5-year) scientific productivity to obtain complementary WFC3/IR grism spectra. of the observatory as well as make the UV information in the archive more accessible to future researchers. A.5.2. Ultraviolet Astrophysics Legacy Program We will ask the TAC to allocate up to 50% of the time available for Large and Trea- With a few limited exceptions, Hubble is the only mission capable of undertak- sury programs to Ultraviolet Astrophysics Legacy proposals in the next three observing ing detailed UV (90–350 nm) observations above the Earth’s atmosphere, now and cycles (Cycles 21–23). We will also instruct reviewers to include “ultraviolet urgency in the foreseeable future. UV observations play a crucial role in mapping the distri- and legacy value” as an additional factor in assessing proposals of all sizes, regardless bution and composition of warm/hot gas in the local universe (Fig. A.5.2.1), prob- of proposal category. Reviewers will be asked to weigh the future value of proposed ing the characteristics of energetic phenomena, revealing the properties of nebulae observations and archival science products for a time when UV observations are not and remnants of stellar evolution, studying stellar winds and chromospheres, and possible. Initial input from the Space Telescope Users Committee (STUC) regarding sampling planetary atmospheres inside and outside the solar system. Hubble UV this initiative is very positive. As we develop the full framework for this new proposal observations with COS, STIS, ACS, and WFC3 are the cornerstone of modern as- category, we will consult with both the STUC and the user community. trophysics investigations at these wavelengths (see Table A.2.2 for capabilities and wavelength regions covered). These capabilities will not always be available, and in A.5.3. The HST Source Catalog the coming decade (or longer) will likely be rarer than optical and near-IR capabili- As of January 1, 2012, HST has taken >106 exposures, containing >109 indi- ties. STIS and ACS are single-string instruments. COS sensitivity, while expected to vidual objects. The diversity of this immense dataset, and the slight imperfections be excellent for at least another 5 years, will eventually degrade. The community (typically 1”–2”) in the registration of HST images taken at different times, make 26 Hubble: Current Performance and Future Expectations 27

it difficult for the average observer to extract basic information (magnitude, color, variability) for individual objects without substantial effort. An HST Source Catalog will provide this type of information quickly in a form that is useful, searchable, and easily accessible. Easily accessible catalogs of astronomical objects are a mainstay of astronomy. A recent example is the Sloan Digital Sky Survey (SDSS) catalog, which is largely responsible for the great success of the SDSS project. One might ask the question, “How much science would have come out of the SDSS if each astronomer had to access the data themselves and make their own catalog?” In the coming decade, sky surveys such as Pan-STARRs and LSST will revolutionize the amount and types of in- formation available for astronomers to mine. However, they will not have the spatial resolution or, in many cases, the photometric accuracy of Hubble. Cross-referencing these new catalogs with an HST Source Catalog will increase the scientific usefulness of these surveys and will have direct benefits for JWST science.

Sh 2-106 (S106), a compact star- forming region in the constellation Cygnus (The Swan). A newly formed star called S106 IR is shrouded in dust at the centre of the image. Wide Field Camera 3 28 29

Annex B Hubble Impact on Science and Media

B.1. Impact of Hubble on Science: Metrics

B.1.1. Publications and Citations fter SM4, Hubble has effectively become a new observatory, with greatly expanded capabilities and wavelength access. Combined with time al- Alocation strategies designed to maximize scientific return (see Annex A), Hubble’s expanded capabilities translate directly into increased scientific pro- ductivity. A wide range of metrics can be used to showcase the great impact that Hubble is having on science. While no single measurement can accurately cap- ture every aspect of Hubble’s impact, a combination of different measurements can certainly paint a more complete picture of the past and current scientific merit of the mission. The most immediate way to measure impact is to count the publications that Hubble observations have produced over the years. In December 2011, the num- ber of refereed publications based on Hubble data surpassed the 10.000 mile- stone. In Figure B.1.1.1, we show the number of refereed science publications based on Hubble data as a function of time since 1981. The time evolution of this number is the most convincing argument that Hubble is on a path of increasing productivity. In 2011 alone, Hubble data produced 795 refereed papers. This is

Number of refereed Hubble publications 800

700

600

500

400

300 WR 25 and Tr16-244, within the open cluster Trumpler 16 in the Carina Nebula. 200 Advanced Camera for Surveys 100 Fig. B.1.1.1. More than 10,250 refereed Hubble papers 0 have been published. Yearly

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 productivity is increasing Year with time, with 795 papers published in 2011. 30 Hubble Impact on Science and Media Hubble Impact on Science and Media 31

the highest yearly output ever for any observatory. Alternatively, we can analyse citations. Hubble papers have been cited in the literature more than 400.000 times. the frequency with which Hubble Space Telescope appeared as a broader concept In Figure B.1.1.2, we show the cumulative citation rate as a function of time. Not in four major astronomical journals. From 2008 to 2010, Hubble science papers only is the number of citations to Hubble papers growing rapidly, but the rate comprised 8% of the papers in ApJ, AJ, MNRAS, and A&A. An additional 10% of the of citations is increasing dramatically, with one half of all citations (>200.000) total papers in these journals discussed Hubble research in the context of analyses occurring since 2006 and nearly one quarter (>100.000) occurring in just the past done with other observatories, theoretical analyses, etc. Thus, approximately 20% two years. If we consider the total, on average each paper has ~40 citations, which of all major astronomical publications are either based on Hubble data or directly indicates quite an impressive impact on astrophysics overall. The high impact of influenced by Hubble’s results or capabilities. Hubble science is also illustrated by the fact that typical papers from the same Hubble enjoys a large community of users: 5680 astronomers worldwide, of journals have only 20 citations on average. whom 1770 are European. We can quantify the European contribution to this wealth The 10 most-cited Hubble papers since launch (Table B.1.1.1) have an aver- of papers: if we count the scientists from the 19 ESA member states who have been age of 1407 citations each and 2 (20%) are led by European astronomers. In 2011 authoring these Hubble publications, we find that, in 2011, 34% of the first authors alone, 34% of all Hubble papers were led by a European scientist. This is an indi- were European, and that this number has been increasing with time. In the same cation that European astronomers have provided a very significant contribution to year, 68% of Hubble papers had at least one European astronomer in their author the dissemination of results obtained by Hubble. list. This is an outstanding demonstration of the benefits of Hubble for the ESA as- tronomical community. It is worth remembering that as part of the Memorandum Table B.1.1.1: Hubble’s Most Highly Cited Papers B.1.2. Proposal Pressure of Understanding between NASA and ESA, European astronomers have access to Cites Paper, Authour, Reference Type and European Success a minimum of 15% of the Hubble observing time. However, especially in the last Type Ia Supernova Discoveries at z > 1 from Another way to measure the Hubble Space Telescope: Evidence for Past cycles, European astronomers have competitively won significantly higher fractions 2258 GO Deceleration and Constraints on Dark Energy interest of a community in of time (26.8% of the available orbits in Cycle 20). Evolution [Riess et al. 2004, ApJ, 607, 665] an observatory is to exam- Another measurement of scientific impact is provided by the citations that Final Results from the Hubble Space Telescope ine the proposal pressure. Hubble papers have gathered over the years. The drawback of using citations as 2014 Key Project to Measure the Hubble Constant GO Demand for Hubble observ- [Freedman et al. 2001, ApJ, 553, 44] an impact measurement is that several years need to elapse in order to realistically ing time is high. In Figure establish the impact of a paper or of a result. Fortunately, Hubble’s baseline is The Demography of Massive Dark Objects in 1787 Galaxy Centers GO/ AR B.1.2.1, we show the over- sufficiently long that we can observe possibly significant trends. After a period [Magorrian et al. 1998, AJ, 115, 2285] subscription as a function of of ~4 years, a typical year’s worth of Hubble papers garners more than ~20.000 Evolutionary Models for Solar Metallicity Low- Cycle (1 Cycle ~ 1 yr), since mass Stars: Mass-magnitude Relationships and 1444 AR Color-Magnitude Diagrams launch, in terms of number 450,000 [Baraffe et al. 1998, A&A, 337, 403] of proposals and number of 400,000 High-redshift Galaxies in the Hubble Deep Field: orbits requested. The figure 1442 Colour Selection and Star Formation History to GO also shows the oversub- 350,000 z~4 [Madau et al. 1996, MNRAS, 283, 1388] scription for proposals us- Cosmological Results from High-z Supernovae 300,000 1137 GO [Tonry et al. 2003, ApJ, 594, 1] ing exclusively the Hubble 250,000 Discovery of a Supernova Explosion at Half the Archive (ranked separately 200,000 1115 Age of the Universe GO and funded by NASA). [Perlmutter et al. 1998, Nature, 391, 51] After the initial few cy- 150,000 New Constraints on Ω , Ω , and w from an M cles plagued by the spheri- Independent Set of 11 High-RedshiftΛ Superno- 100,000 979 GO vae Observed with the Hubble Space Telescope cal aberration, the pro- 50,000 [Knop et al. 2003, ApJ, 598, 102] posal oversubscription has Cumulative Number of Citations The Photometric Performance and Calibration been ranging between four 974 of WFPC2 GO/AR Fig. B.1.1.2. Citations to [Holtzmann et al. 1995, PASP, 107, 1065] and eight. The post-SM4 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 Hubble papers are increasing The Hubble Deep Field: Observations, Data oversubscription rates are dramatically, roughly doubling Year of Citation 921 Reduction, and Galaxy Photometry GO among the highest on re- in just the past 5 years. [Williams et al. 1996, AJ, 112, 1335] cord. In Cycle 19, the over- 32 Hubble Impact on Science and Media Hubble Impact on Science and Media 33

subscription rates were 6:1 in terms of proposals and 9:1 in terms of orbits. In B.2. Hubble in the Media Cycle 20, the most recent cycle, we recorded 5:1 in terms of proposals and 6:1 in terms of orbits. In the past few years, our goal has been to continue highlighting Hubble results As already mentioned, European astronomers have guaranteed access to 15% obtained by European astronomers and keep Hubble present and prominent in Eu- of the Hubble time. In Figure B.1.2.2, we show the success rate for astronomers rope so that the community of European Hubble users feels involved and informed from ESA member states. Typically, European Principal Investigators have enjoyed at the same level as the US as- a success rate ranging from 13% (Cycle 16) to 28% (Cycle 8) in terms of pro- tronomical community. This is posals. Cycle 20 has been particularly successful for European astronomers, with done through ESA/Hubble. Here European-led proposals competitively winning 19.7 % of the proposals and being is a high-level summary of the allocated 26.8% of the orbits available. activities that ESA/Hubble car- ries out, and of their impact. B.2.1. Science Releases 10.00 Cycle 20 New discoveries and theo- GO Orbit oversubscription 9.00 GO Proposal oversubscription ries are regularly presented, AR Funding oversubscription 8.00 when they are published in peer-reviewed journals. Euro- 7.00 pean science is showcased — 6.00 science releases are only pro- 5.00 duced for papers with at least 4.00 one European co-author. There 3.00 were four science releases in Oversubscription Ratio the first six months of 2012. 2.00 There were also four in the SM4 1.00 SM4 same period of 2011. Fig. B.1.2.1. Demand for Hubble 0 A variety of visually in- observing time and archival 1 2 3 4 5 6 7 7N 8 9 10 11 12 13 14 15 16 17 18 19 20 triguing photo releases are also research funding since SM4 is Cycle presented — Hubble observa- near all-time highs. tions, whether new or archival, 30% are presented with explanatory text. There were five photo re- 25% leases in the first six months of 2012. (There were seven in the 20% same period of 2011.) ESA/Hubble press releases 15% received extensive coverage dur- Accepted ing the first six months of 2012. 10% Images and videos from press releases also regularly feature on 5% Proposals Orbits the popular Astronomy Picture Fig. B.1.2.2. Fraction of 0% of the Day website, in documen- European-led programmes as 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 tary programmes, in Wikipedia a function of cycle, in terms of Cycle articles, in books, and more proposals and orbits allocated. broadly in popular culture. 34 Hubble Impact on Science and Media Hubble Impact on Science and Media 35

ESA/Hubble also pro- B.2.3. Podcasts duces a shorter type of news ESA/Hubble’s video podcast series, the Hubblecast, showcases new Hubble sci- story, which is published only ence and images , along with computer simulations. Presented by Dr Joe Liske (aka on the spacetelescope.org “Dr J”), the Hubblecast has established itself as a popular source of astronomy news website (and not proactively on YouTube and through iTunes. It is produced approximately monthly, and episodes sent to the media). These an- are around 4–10 minutes long. nouncements cover a range In the first six months of 2012, the Hubblecast has continued to perform of topics such as new podcast strongly, and remains one of the most popular science vodcasts in the world. The episodes or products becom- second series of Hubble: Mission Universum, a spinoff programme on Austrian ing available, as well as stories TV, hosted by Joe Liske, is currently in production, while Episode 56 was featured that do not merit a full release on MailOnline, the most visited newspaper website in the world (99 million but are still of interest to the visits per month). The Hubblecast’s popularity can be measured through Apple’s community. Seven announce- iTunes podcast store, which is by far the largest directory of video podcasts on ments have been published the Internet. ESA/Hubble maintains daily statistics on the Hubblecast’s popularity so far in 2012, most notably on this platform, for downloads in the UK and US (the two leading English- advertising the move of the language markets). The Hubblecast has performed similarly well in the German European Hubble Archive to iTunes store, despite the podcast only being available in English for part of the ESAC. Fig. B.2.3.1. Hubblecast period. Some of ESA/Hubble’s popularity index relative to releases are produced in other science podcasts. collaboration with the Space Telescope Science Institute’s Office of Public Outreach (OPO). B.2.2 Pictures of the Week 1 Hubblecast A new product introduced in 2010, the Hubble Picture of the Week, has become 10 HD Science a significant part the Hubble outreach portfolio. Presenting newly processed ar- UK iTunes chival images along with short explanatory texts, the Hubble Pictures of the Week 20 Hubblecast are promoted on spacetelescope.org and through social media such as Facebook. 30 HD Science Starting in Summer 2012, Hubble Pictures of the Week will be regularly featured in US iTunes the ESA Space Science Picture of the Week series. 40 While Picture of the Week is not pitched directly to the press, the images are made CC HD 50 Science UK available under the same copyright terms, and a number have been picked up by me- iTunes Popularity index Popularity dia organisations. Discover Magazine (with over two million online visitors per month) 60 regularly features Hubble pictures of the week on its Bad Astronomy blog, as does EC HD NASA’s Astronomy Picture of the Day. 70 Science US Pictures of the Week, like photo releases, are all submitted to Wikimedia Commons, iTunes 80 the shared media archive for Wikipedia and related projects. As well as providing 28 28 28 28 28 28 28 28 28 28 28 28 28 illustrations for many astronomy articles in the world’s most popular encyclopaedia Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun (see for example http://en.wikipedia.org/wiki/NGC_7479), Wikimedia Commons is 2011 2012 widely used as a source of royalty-free images by third parties, further disseminating Hubble images beyond ESA/Hubble’s standard distribution channels. 36 Hubble Impact on Science and Media Hubble Impact on Science and Media 37

Multilingual subtitles were launched for the Hubblecast in April 2012 and are currently being progressively rolled out through the archive, in collaboration 12,000 with a team of volunteer astronomy enthusiasts. 10,000 Twitter followers The chart in Figure B.2.3.1 shows that Hubblecast HD alone (one of three Hubble Twitter followers formats offered) is one of the most popular video podcasts in iTunes’ science 8,000 ESO Twitter followers and medicine section, consistently in the top 10 in both the UK and the US, com- 6,000 Linear (Hubble Twitter followers) pared, for example, with the ESOcast. Linear (ESO Twitter followers) 4,000 B.2.4. Social Media Twitter followers Social media are a major focus of attention in 2012. By August, Hubble’s 2,000 Facebook page at facebook.com/hubbleesa surpassed 100.000 fans (more than 0 twice as many as STScI/OPO’s Hubble page, and four times as many as ESO), and the Twitter feed at twitter.com/hubble_space had 10.300 followers. Numbers of Facebook and ESA/Hubble Twitter followers show a strong upward trend. Apr 1 • 2010 Jul 1 • 2010 Jul 1 • 2011 Jul 1 • 2012 Oct 1 • 2010 Apr 1 • 2011 Oct 1 • 2011 Apr 1 • 2012 There has been a marked acceleration in the increase of Twitter followers since Jan 1 • 2011 Jan 1 • 2012 Hubblecast 50 (in which Twitter and Facebook fans were invited to send their questions to Dr Joe Liske). ESA/Hubble has now overtaken ESO’s Twitter fol- Fig. B.2.4.1. Hubble lower count. as they are published. More than this, however, social media provide a unique op- followers on Twitter. Figures B.2.4.1 and B.2.4.2 show the progression in followers for ESA/Hub- portunity to engage members of the public (for example by answering questions in ble (and ESO for comparison) on Facebook and Twitter over the past two years. comment threads, or inviting questions to be discussed in the Hubblecast), rather Fig. B.2.4.1. Hubble fans ESA/Hubble’s Facebook and Twitter pages are updated with links to all ESA/ than just directing information at them. on Facebook. Hubble press releases, announcements, pictures of the week and Hubblecasts, The Facebook page in particular has developed into a forum for Hubble fans to discuss new images and results, share information with each other, and ask ques- tions. Twitter has become an important tool for science journalists to find stories,

100,000 though the Twitter feed is also an opportunity to engage the public.

90,000 B.2.5. Other Initiatives Facebook fans 80,000 B.2.5.1 The Hubble Hidden Treasure Competition Hubble Facebook fans 70,000 Hubble’s archive is very large (containing data from over 1,000,000 observa- ESO Facebook fans tions), and while professional astronomers are typically familiar with data rel- 60,000 evant to their work, nobody has ever 50,000 had a comprehensive overview of the

Facebook fans 40,000 content of the archive for public out- reach purposes. 30,000 ESA/Hubble therefore launched 20,000 an amateur image processing competi- 10,000 tion in April 2012, to crowdsource the searching of the archive for interesting 0 objects, and engage with a small but passionate group of astronomy fans. The competition was modelled on Jul 1 • 2010 Jul 1 • 2011 Jul 1 • 2012 Apr 1 • 2010 Oct 1 • 2010 Apr 1 • 2011 Oct 1 • 2011 Apr 1 • 2012 Jun 1 • 2010 Sep 1 • 2010 Nov 1 • 2010 Jan 1 • 2011 Feb 1 • 2011 Jun 1 • 2011 Sep 1 • 2011 Nov 1 • 2011 Jan 1 • 2012 Feb 1 • 2012 Jun 1 • 2012 May 1 • 2010 Aug 1 • 2010 Dec 1 • 2010 Mar 1 • 2011 May 1 • 2011 Aug 1 • 2011 Dec 1 • 2011 Mar 1 • 2012 May 1 • 2012 Aug 1 • 2012 a similar initiative carried out by ESO in 2010. 38 Hubble Impact on Science and Media 39

The competition was split into two categories: a simple archive scavenging competition, with prizes for the best unpublished images found; and an advanced image processing competition where contestants were invited to try out the same advanced software as used by ESA/Hubble’s in-house image processing staff. The response rate was exceptionally high for what is unquestionably a niche interest: there were over 1600 entries in the simple archive searching competition and almost 1200 in the advanced image processing competition, for a total of just under 2800. In comparison, the ESO image processing competition in 2010 at- tracted fewer than 100 entries in total. The results are currently being compiled and judged, and the winners will be announced in the autumn of 2012. Datasets identified in this initiative will be fea- tured in future ESA/Hubble photo releases and Pictures of the Week.

Hubble images and related hardware featured in an exhibit that ESA organized in Venice in October 2010.

More than 13.000 people visited Interacting galaxies Arp 273. the display in one month. Wide Field Camera 3 40 41

Annex C The Scientific Impact of the Hubble Archive

C.1. The Hubble Archive ubble has greatly influenced not only science, but also the way to do science. At the time of Hubble’s launch, data dissemination was Hrestricted to distributing data to the Principal Investigators of Hubble programmes. It soon became clear that, in order to optimise the science return from Hubble, data would have to be made available to the wider astronomical community, once the proprietary period of the data had elapsed. In the 1990s, the Hubble archive and pipeline revolutionised the way astronomers worked, and provided an order-of-magnitude improvement in the ability to use observations for science. Instead of each astronomer hav- ing to take the data individually, Hubble observations are taken once and put into the archive where anyone has access to them. In addition, instead of scientists having to do their own basic reductions (i.e., flat-fielding, bias subtraction, image combination, etc.) the data are reduced and calibrated uniformly as part of the general pipeline processing, hence greatly reduc- ing the need for redundant work by the astronomical community. In recent years, this approach has become the norm for many major telescopes and other large projects.

HST archive activity 7000 SM4 Retrievals Ingest 6000 ACS (WFC3, COS, ACS, STIS) failure SM3B 5000 (ACS, NCS) 4000

3000

2000 Gigabytes per month Gigabytes

1000 Overlapping galaxies NGC 3314. 0 Advanced Camera for Surveys

01/2001 01/2002 01/2003 01/2004 01/2005 01/2006 01/2007 01/2008 01/2009 01/2010 01/2011 01/2012 Fig. C.1.1. Hubble archive activity Year over time, displayed in terms of data ingest and user retrievals. 42 Scientific Impact of the Hubble Archive Scientific Impact of the Hubble Archive 43

Today, the classical Hubble archive contains over one million observations, Refereed HST publications Fig. C.1.3. The European con- or the equivalent of about 70 Terabytes of data. The research community already 900 tribution is highlighted in each Of the HST Archive publications since 2005, Other publication category: Pure Ob- retrieves several times more data from the Hubble archive than is put in or “in- 800 45% are from European PIs gested”, indicating that Hubble data are used for purposes beyond their original Partial Archive servations, Pure Archive, Partial 700 intent (Fig. C.1.1). Archive, and Other. Archive The increasing importance of the Hubble archive is also reflected by the fact 600 that roughly two thirds of the refereed papers based on Hubble data use archival Observations 500 information. While the number of papers authored by the Principal Investigator (PI) teams that proposed the respective Hubble observations has been roughly 400 Fig. C.1.2. Refereed Hubble constant at the level of about 250 per year over the last decade, the number of pa- 300 pers from archival research carried out by scientists other than these PI teams has publications (deriving from 200

original data sets, from increased significantly and peaked at about 450 per year (Fig. C.1.2). Publications Refereed combinations of original and Hubble will provide excellent scientific data for many more years after SM4. 100 archive data, and purely based on But as the conclusion of the Hubble mission inevitably draws nearer, interest will 0 archival data). turn even more to the analysis of archival data and to the establishment of the 2005 2006 2007 2008 2009 2010 2011 Year

true legacy of this mission. In the end, archival papers will certainly dominate the Hubble mission’s science impact. In this context the attractiveness of the usage of the archive has a direct, measurable impact on science. It is also interesting to note that archival papers are cited at the same rate as PI-led papers, and that these archival papers are represented as expected among the most highly cited papers. European astronomers are playing an increasingly significant role in the scien- tific exploitation of the Archive. If we highlight, in the graph in Figure C.1.3, the contribution of European astronomers in each category of publications: observa- tions, pure archive, partial archive (which means that the publication is based partly on observations and partly on archive data), and unassigned, we see that in 2011 alone, almost half (48%) of the publications based purely on archival data were led by European astronomers. This ratio has been slowly increasing with time, with the implication that European astronomers easily access the Hubble archive and come up with very original and creative ideas to scientifically exploit this very rich data set. Hubble is expected to provide excellent scientific data for many more years, augmenting further the already rich data set available. As holdings grow, larger statistical and correlative studies can be carried out. Interesting and diverse sci- ence investigations, spanning all areas of astrophysics, can be easily accomplished by mining the wealth of observations already taken at different wavelengths, with different techniques, at different epochs. The rapid increase in computer power combined with the even more rapid decrease in the cost of disk space (by five orders of magnitude since the launch 4444 Scientific Impact of the Hubble Archive Scientific Impact of the Hubble Archive 45

of Hubble), and the advent of the Internet, have effectively broadened the use of lish the European Hub- Fig. C..1.4. The official opening of astronomical observations. Rather than sending off a request for archival data and ble Archive at the Euro- the European Hubble Archive at waiting several hours, it is now possible to keep all the data on line and to make pean Space Astronomy ESAC took place on June 22, 2012. them available in real time. In addition, a host of potential new opportunities Centre (ESAC) in Spain. From left to right: Antonella Nota, for streamlining the research process are made possible, for instance by efficient After the closing of the HST Project Scientist & Mission browsers displaying images and ancillary data, and by additional but uniformly ST-ECF at the end of Manager; Christophe Arviset, derived high-level data products. Finally, the availability of the data to anyone with 2010, it became apparent Head of the Science Archives and a computer represents an orders-of-magnitude increase in the potential audience that the European South- Computer Support Engineering Unit at ESAC; William Smith, for Hubble data. ern Observatory (ESO), President of the Association This realisation provided the impetus to embark on the development of the which had hosted the ST- of Universities for Research in Hubble Legacy Archive (HLA) since 2007 in an international collaboration between ECF, would not maintain Astronomy (AURA); Álvaro STScI, the ST-ECF (until 2010), the Canadian Astronomy Data Centre (CADC), and a copy of the European Hubble Archive. A decision was then taken to transfer Giménez Cañete, Director of now also the European Space Astronomy Centre, which also holds the archives of the data and the know-how to the European Space Astronomy Centre (ESAC) Science and Robotic Exploration. all major ESA missions. The potential enhancement to the overall Hubble science in Spain, and to establish there the only European mirror site for the Hubble from the HLA resulted from three primary sources. The first was the ability to Legacy Archive. A very effective collaboration between STScI and ESAC resulted quickly (via online access) and easily (via a graphical footprint service) browse the in the successful transfer of the entire archive system to ESAC and its integration Hubble database to find datasets of interest, and to discover new datasets. This is a into the ESAC environment. Both the cache of calibrated data and the HLA are primary requirement for a targeted mission with non-uniform imaging capabilities, now available at the European Hubble Archive at ESAC. During the official open- such as Hubble, unlike large all-sky survey missions like 2MASS, SDSS, and GALEX ing ceremony on June 22, 2012, Prof. Álvaro Giménez Cañete, ESA’s Director of where uniform coverage is provided. In addition, while entire images still take a Science and Robotic Exploration said: “This year, European astronomers were few minutes to download due to the limited bandwidth across the Internet, smaller awarded a record share of observing time with Hubble. Bringing the Hubble “cutouts” of selected regions can be displayed in tenths of seconds, optimized for science archive to ESAC is part of ESA’s continuing commitment to European the resolution of the target screen. astronomers having access to the world’s most famous orbiting observatory” The second driver was the production of new products. These include enhanced (Fig. C.1.4). images (stacks, mosaics, color, contributed, etc.) that have been astrometrically cor- rected when possible, spectra and grism extractions, as well as source lists, and eventually an Hubble all-sky source list. The third driver was the removal of a high level of redundancy, reminiscent of the revolution in archival science two decades ago. Rather than each astronomer needing to make separate corrections for astrom- etry, combining the images into higher-level stacked images and mosaics, and devel- oping their own source lists, the HLA provides these services in a uniform manner. With Data Release 6 in early 2012, the Hubble Legacy Archive now contains virtually complete sets of ACS, WFPC2 and NICMOS data, and about 65% of all WFC3 data. In addition, source lists and new externally supplied high-level science products are now available. Regarding the HLA user interface, the report of the most recent NASA Astro- physics Archival Senior Review stated that “the power and speed of the HLA inter- face convinced panel members that it may be the best multi-mission data browser in existence”. In addition, all Hubble data in the HLA are accessible through stan- dard Virtual Observatory interfaces. This improved archive is expected to provide an essential research resource for many years, if not decades. Recognising the scientific importance of the Hubble Legacy Archive in relation to the scientific exploitation of the Hubble Mission, a decision was taken to estab- 46 47

Annex D Working Together: Synergy with Other Missions

t has been frequently remarked that scientists are now enjoying a golden era of astronomy. There are now observatories in orbit that cover most regions of the Ielectromagnetic spectrum, from high energy to the far-IR (Integral, XMM New- ton, Chandra, Hubble, Spitzer, Herschel, Planck and soon JWST), and these superb facilities are complemented by state-of-the-art ground-based instrumentation (VLT, Keck, Gemini, Subaru, ALMA and, in the future, ELT, GMT and TMT). This situation is unique in the history of astronomy. The way to do research has also evolved at the same fast pace. As already highlighted, scientific collaborations have grown larger and larger, and have moved beyond national and continental barriers. The progress in communication technology has minimised the effects of physical distance. Astronomers do not restrict their studies to one wavelength regime, but have learned to take full advantage of the facilities available. Multiwavelength studies of astrophysics phenomena have become the norm and coordinated observations among different observatories are now implemented in a routine Table D.1: Science Synergy with Other Missions way. The unique capabilities of each facility are optimally Recent Investigation Mission exploited. Ly blobs at high-z Ultra-coldα brown dwarfs WISE Hubble’s location above the New debris disks atmosphere, access to the UV Luminous z > 1.6 IR galaxies domain, low sky-backgrounds Gravitational lenses Herschel in the near-infrared, diffraction- Trans Neptunian objects limited imaging in the optical, ICM cooling and AGN heating stable well-characterized point Cool cores in galaxy clusters GALEX, Herschel spread function, and unprec- Ly in star-forming galaxies GALEX edented pointing stability make Blackα hole ESO243-49 HLX-1 GALEX, Swift Hubble and Chandra observations reveal it a natural complement for as- GRB host galaxies Asteroid collision debris the separation of dark matter (blue) and Swift trophysical studies conducted Supersoft X-ray phase novae normal matter (red) in Pandora’s Cluster by other observatories. With its Low-z superluminous SNe (Abell 2744). unique capabilities, Hubble also Transiting exoplanets Kepler Hubble Advanced Camera for Surveyss/ plays an important role in coor- Pluto environment Wide Field Camera 3 New Horizons dinated science programs and ESO Very Large Telescope Vesta rendezvous Dawn spacecraft trajectory updates for Chandra X-ray Observatory Comet 103P/Hartley 2 flyby DIXI/EPOXI NASA and ESA planetary mis- Venus atmosphere Venus Express (ESA) sions (Table D.1). Lunar impact coordination LCROSS 48 Working Together: Synergy with other Missions Working Together: Synergy with other Missions 49

obtain also deep images in the blue and UV where the galaxies truly at high Table D.2: Reciprocal Observing Agreements redshifts must not be detected. The Hubble ACS and WFC3/UVIS imagers HST TAC may award, per cycle Other TAC may award, per cycle Status are capable of obtaining these deep images at wavelengths below the short Chandra Up to 400 ksec Up to 100 HST orbits (750 total in Cycles 9-19) Ongoing wavelength cutoff of JWST at 600 nm (see §A.5). Spitzer Up to 60 hours Up to 60 HST orbits (117 total in Cycles 14-19) Ended in Cycle 19 WFC3 and ACS can also do much of the necessary preparatory work for XMM-Newton Up to 400 ksec Up to 30 HST orbits New in Cycle 20 the rapid exploitation of the JWST Near Infrared Spectrograph (NIRSpec), for which the spectroscopic target lists require high accuracy (~10 mas) astrom- etry that is very difficult to obtain with ground–based telescopes. Obviously, Hubble has a rich tradition of cooperation on science projects of all sizes. The some of the Hubble data will be obtained before JWST is launched. However, most notable of these are the deep-field surveys. The UDF, GOODS, COSMOS and results of the first JWST observations will shape future directions of research CANDELS fields that have been observed extensively by Hubble have been ob- and inspire follow-up observations if Hubble is still operational. Therefore, served with XMM-Newton and Herschel, and deep spectroscopic follow-ups have one of the primary drivers in our strategic planning for Hubble operations been obtained with the VLT. is the goal of ensuring at least a year of overlapping science operations with Opportunities to propose joint HST observing programs with Chandra or JWST). Spitzer have been possible for many years. Beginning in Cycle 20 a similar arrange- ment will be in place for XMM-Newton (Table D.2). Such agreements remove the double jeopardy that proposals seeking coordinated observing time would other- D.2. Synergy between Hubble and Current Planet-finding wise face in two independent, oversubscribed peer reviews. Missions Hubble has unique capabilities that have advanced the rapidly expand- D.1. Synergy between Hubble and JWST ing field of exoplanet research. Hubble was the first observatory to spectro- scopically detect the constituent components of an exoplanet atmosphere. Hubble is also a synergistic precursor to the James Webb Space Telescope Subsequent observations of the transiting “hot Jupiter” system HD 209458b (JWST). Both observatories have comparable point spread functions at their re- led to the detection of carbon, oxygen, and hydrogen absorption. Hubble was spective operating wavelengths, meaning that it will be possible to produce multi- also the first observatory to detect an organic molecule (methane) in an exo- wavelength views of distant objects and other sources that cannot be resolved planet atmosphere. These capabilities are complementary to those available by other telescopes. The investment of ESA in JWST has been significant and the on Spitzer and Herschel (Fig. D.1). expectation of scientific return for the European community is high. One of the four science themes driving the requirements of JWST is the assem- bly of galaxies, and one of the top-level questions in this theme is how galaxies exchange gas and energy with the intergalactic medium. JWST is superbly suited 1.80 H2O + CH4 XO-1 transit spectrum H O + CH to measure the metallicity, gas properties and dynamical state of high-redshift 2 4 CO + CO? Fig. D.1. Hubble near-IR galaxies. However, JWST is limited in its capacity of probing the intergalactic me- 2 1.75 CO dium because of its wavelength range and of the design choice of including only 2 spectroscopy reveals the molecular medium and low resolution spectroscopic capabilities. The Hubble sequence is components of exoplanet CO atmospheres (including H O) and established at relatively low redshift (probably below z=3) and at these redshifts 2 2 1.70 complements longer wavelength Lyman break galaxies undergo strong bursts of star formation and the presence of band-averaged photometric winds is common. In order to obtain a complete picture of the processes involved measurements made by Spitzer. Absorption (%) in the mutual interaction of galaxies and intergalactic medium it is essential to 1.65 WFC3 extends previous NICMOS match JWST data on galaxies to Hubble COS data on the cosmic web. NICMOS data studies at these wavelengths The first light and reionisation theme and the assembly of galaxies theme both Model to fainter objects and will require JWST to observe faint galaxies at high redshift. The faintest galaxies de- 1.60 place stronger constraints on 1.2 1.3 1.4 1.5 1.6 1.1 1.8 tected by JWST will be too faint to measure their spectroscopic redshifts and one the composition of exoplanet will have to rely on photometric redshifts. However, in order to rule out the pos- Wavelength (microns) atmospheres. At least 15 transiting sibility that some of these objects may be low redshift interlopers it is essential to systems are under study. 50 Working Together: Synergy with other Missions 51

At the moment, there are two planet finding missions in operation: CoRot, and Kepler. CoRot is led by CNES, with a number of European partners — it carries a 27-cm telescope equipped with a camera and its goal is to discover planets by observing the periodic mini-eclipses that occur when the planet transits in front of the parent star. Kepler is US-based, and has a bigger telescope (95cm). CoRot has been in orbit since late 2006 and has collected ~150,000 light curves. CoRot has found at least 27 new exoplanets, including one that is of near Earth size. Ke- pler was launched in 2009 and NASA has recently approved a mission extension to 2016. Kepler is monitoring more than 150,000 stars, and has so far discovered 74 confirmed exoplanets, including Earth-like planets, and over 2300 exoplanet candidiates. These observations provide the best opportunity in the near future to detect earth-like exoplanets within about 150 pc from the Sun. The host stars will be rela- tively bright (V < 11), which makes them ideal targets to search for possible bio- markers through spectroscopic studies. However, in the case of Kepler, the images will be defocused so that most of the observed stars will be “blended” with fainter stars within the PSF, which makes it difficult to distinguish between a Jupiter-like planet orbiting a “blended”, fainter star and an earth-like planet orbiting a bigger, brighter star. The only clean way to confirm the “earths” found by these missions would be through observations similar to the Hubble observations of HD 209458 (Fig. D.1), where high S/N observations (S/N ~ 105), coupled with the high spa- tial resolution will make the earth-like signal unambiguous. Given the expected lifetimes of the two missions and the time that is necessary to confirm a transit it will be crucial to have Hubble operational over the next 5 years at least to confirm unambiguously these discoveries.

Starburst cluster NGC 3603 Wide Field Camera 3 52 53

Annex E Cost of Hubble’s Extension (2013–2014) to ESA

E.1. The Cost of Hubble’s Extension (2015–2016) to ESA he great scientific merit of continued European involvement in the Hubble project is discussed elsewhere in this document. Here we will solely con- Tcentrate on the topic of cost, putting it in perspective with respect to the funding from NASA. In this context it is important to recall the initial plans at the beginning of the NASA/ESA collaboration on Hubble: Europe would be guaranteed a minimum of 15% of the available observing time on Hubble, in exchange for an estimated 15% investment consisting of instruments (the Faint Object Camera) and the solar panels (plus the required engineering support), and 15% of the staff of the then planned Space Telescope Science Institute, which was expected to require about 100 individuals to support Hubble science operations. The 15% in both cases — hardware and personnel — were immediately over- taken by reality: the longevity of Hubble paired with the lack of further hardware provisions (with the notable exception of a second set of solar panels) from ESA lowered this percentage considerably. In the case of the ESA personnel stationed at STScI, the staff required to actually run the science operations peaked at over 400 within a few years of launch. Even today, this number is about 230. Not counting the ST-ECF, which was closed at the end of 2010, this means that the personnel complement that ESA provides is only about 6.5%. This percentage has to be weighted against the time percentage that European PIs have received during the Hubble mission. In Cycle 20 alone, European PIs obtained an amazing 26.8% of the total number of Hubble orbits allocated. This is almost twice the nominal value, and is a strong indication that the interest of European astronomers in Hubble is at an all-time high. If we consider the operations costs for Hubble during routine operations, ESA has expended between 4M€ and 5 M€ per year for this task, a number that Star-forming region in 30 Doradus, in the heart of the Tarantula Nebula. dropped to 3.5 M€ in 2012. As a comparison, NASA has found it justifiable and advantageous to bear, in the past few years, the considerable cost of ~350 M$ Hubble Advanced Camera for Surveys/ (FY06 – FY08) per year for operations and development (note that these numbers Wide Field Camera 3y do not include the cost of the flights of the Space Shuttle). In February 2012, Hubble was evaluated as part of the NASA Senior Review of their missions in operation. The review included: Chandra, Fermi, Hubble, Kepler, Spitzer (Warm), Swift, and U.S. participation in the Planck, Suzaku, and XMM-New- 54 The Cost of Hubble’s Extension to ESA The Cost of Hubble’s Extension to ESA 55

ton missions. The requested FY12 operating budget for Hubble was approximately IV. Maintenance of the only European Hubble Archive, now established at $95M, of which about 1/3 go to grants to the US community and E/PO activities, ESAC. 1/3 to support science operations at STScI, and 1/3 to support mission/flight op- erations, sustaining engineering, and Project management at GSFC. Hubble fared very well in this review. It received “Excellent” scores for “Discovery Space”, “Long Term Impact”, “Synergy” [with other missions], and “Critical Capability”. It received a “Very Good” score for “Publications Per Dollar”. From the final Senior Review report: “HST provides excellent, cutting edge science at a total cost of about $95M per year, of which about $25M annually is GO funding. Continued high-impact scientific contributions over a wide range of fields are anticipated. Great care has gone into the allocation of observing time, the delivery of calibrated data products, along with software tools for use with the data sets. The HST team has been forward-looking in developing a variety of procedures that can extend the lifetime of the mission”. NASA, therefore, committed to fund Hubble at a constant level throughout 2016, to allow full scientific exploitation of the new scientific capabilities enabled by SM4. We request that ESA continue its very valuable involvement with Hubble and fruitful partnership with NASA. The ESA budget request to support Hubble operations includes: I. Support of the 15 ESA scientists and contractors deployed by ESA at STScI to support Hubble operations as defined by the MOU. These scientists serve in important positions in that organisation and continuously look after the interests of the European astronomical community. II. Technical support for the ESA-provided hardware still on-board Hubble (SA-3 Solar Array Drive Mechanism, Solar Array Drive Electronics, and DCE) to ensure that it remains fully operational. The ESA-provided hard- ware has been performing well in-orbit since 1993 (SADE, DCE) and 2002 (SA-3 SADM), respectively. In order to ensure operations during the extension, ESA needs to continue sustaining engineering support, moni- toring the ESA-provided hardware (SA-3 SADM, SADE, and DCE) in-orbit performance and contributing to potential in-orbit anomaly resolution activities. This may include, but is not limited to, performance trending, assessment of precautionary measures to minimize risks of hardware failure, anomaly resolution, VEST hardware maintenance, and life exten- sion activities. This activity also includes management/planning of ESA/ NASA Hubble project interface and industry support activities. Dwarf galaxy NGC 4214. Wide Field Camera 3 III. Support to the ~25 European astronomers who participate in the Hubble Time Allocation process and other high level committees (e.g. Space Telescope Users Committee, Institute Visiting Committee, etc.). 56 57

Annex F Supporting Documentation

F.1. Letter from Mr. Mansoor Ahmed, Assoc. Director, Astrophysics Projects Div., NASA/GSFC

Spiral Galaxy M66 Advanced Camera for Surveys/ Wide Field Camera 58 Supporting Documentation Supporting Documentation 59

(Letter from Mr. Mansoor Ahmed, Astrophysics Projects Division, cont’d.) F.2. Letter from Prof. Mario Mateo, Space Telescope Institute Council Chair 60 Supporting Documentation Supporting Documentation 61

(Letter from Prof. Mario Mateo, Hubble Space Telescope Council Chair, cont’d.) (Letter from Prof. Mario Mateo, Hubble Space Telescope Council Chair, cont’d.) 62 Supporting Documentation 63

F.3. Letter from Prof. Louis-Gregory Strolger, Hubble Space Telescope Users Committee

Hanny’s Voorwerp, the only visible part of a 300,000-light-year-long streamer of gas stretching around galaxy IC 2497. Advanced Camera for Surveys/ 65

Detail of the “Mystic Mountain” inthe Carina Nebula. Wide Field Camera 3 Acknowledgments

We wish to express our sincere gratitude to the many people at STScI and ST- ECF who have helped us producing this document. The compilation of the impact data is due to Daniel Apai and Jill Lagerstrom, expert librarian at STScI, with the help of Karen Levay. Brett Blacker and Claus Leitherer have kindly provided precious information on the time allocated to the astronomical community. We are grateful to Alessandra Aloisi, Tony Keyes, and John MacKenty for providing essential information on the new instruments. We are grateful to Robert Fosbury (ST-ECF) and Duccio Macchetto for contributing wording to the document and for the long-lasting contribution of the ST-ECF to the Hubble project. Heartfelt thanks to Carol Christian, Marc Postman, Neil Reid, and Ken Sembach at STScI for their careful reading of the document, and to Chad Smith for the very well-produced copies of the paper version of the document. We also wish to thank Ahmed Mansoor and Thomas Griffin (NASA/GSFC), Neta Bahcall (Princeton), Eric Smith (NASA HQ), and Lori Lubin (University of California Davis) for their endorsement of this proposal. Finally, a heartfelt thanks to Ann Feild, who worked so hard to give to our dry words such a beautiful frame. 66 67

Acronyms Image Credits ACS Advanced Camera for Surveys ALMA Atacama Large Millimeter/Submillimeter Array AR Archival Proposals Cover ����������������������Star-forming region in 30 Doradus in the Tarantula Nebula. NASA, ESA, D. Lennon, CADC Canadian Astronomy Data Centre and E. Sabbi (ESA/STScI); J. Anderson, S. E. de Mink, R. van der Marel, T. Sohn, and CDFS Chandra Deep Field South N. Walborn (STScI); N. Bastian (Excellence Cluster, Munich); L. Bedin (INAF, Padua); CNES Centre National d’Etudes Spatiales COS Cosmic Origins Spectrograph E. Bressert (ESO); P. Crowther (University of Sheffield); A. de Koter (University of COSMOS Cosmological Evolution Survey Amsterdam); C. Evans (UKATC/STFC, Edinburgh); A. Herrero (IAC, Tenerife); N. Langer COSTAR Corrective Optics Space Telescope Axial Replacement (AifA, Bonn); I. Platais (JHU); and H. Sana (University of Amsterdam). E-ELT European Extremely Large Telescope, ESA European Space Agency Inside cover �����������Stellar field in the Sagittarius Window. NASA, ESA, W. Clarkson (Indiana University ESO European Southern Observatory and UCLA), and K. Sahu (STScI). ESTEC European Space Research and Technology Centre FGS Fine Guidance Sensor FGS-2R FGS 2nd Replacement Unit ii ������������������������������Spiral galaxy NGC 2397. NASA, ESA, and S. Smartt (Queen’s University Belfast, UK). FOC Faint Object Camera FOV Field of view GEMS Galaxy Evolution From Morphology And SEDs iii ����������������������������Infrared image of the “Mystic Mountain” in the Carina Nebula. NASA, ESA/M. Livio, GMT Great Magellan Telescope Hubble 20th Anniversary Team (STScI). GO Observing Proposals GOODS Great Observatories Origins Deep Survey HD High definition iv ����������������������������“Mystic Mountain” in the Carina Nebula. NASA, ESA/M. Livio, Hubble 20th-Anniversary HDF Hubble Deep Field Team (STScI). HEIC Hubble European Information Centre HETE-2 High Energy Transient Explorer 27 ���������������������������Compact star-forming region S106. NASA, ESA, the Hubble Heritage Team (STScI/ HLA Hubble Legacy Archive AURA), and the Subaru Telescope (National Astronomical Observatory of Japan). HRC High Resolution Camera HST Hubble Space Telescope IGM Intergalactic medium 28 ���������������������������WR25 and Tr16-244. NASA, ESA, and J. Maiz Apellániz (Instituto de Astrofíscia de IR Infrared Andalucía, Spain). IRAC Infrared Array Camera ISAAC Infrared Spectrometer And Array Camera ISM Interstellar medium 39 ���������������������������Interacting galaxies Arp 273. NASA, ESA, and the Hubble Heritage Team (STScI/ ISO Infrared Space Observatory AURA). Acknowledgment: Z. Levay JWST James Webb Space Telescope LST Large Space Telescope 40 ���������������������������Overlapping galaxies NGC 3314. NASA, ESA, and the Hubble Heritage Team (STScI/ MCTP Multi Cycle Treasury Program AURA). Acknowledgment: Z. Levay. MOU Memorandum of Understanding NASA National Aeronautics and Space Administration NIC3 NICMOS Camera 3 46 ���������������������������Pandora’s Cluster (Abell 2744). NASA, ESA, J. Merten (Institute for Theoretical NICMOS Near Infrared Camera and Multi-Object Spectrometer Astrophysics, Heidelberg/Astronomical Observatory of Bologna), and D. Coe (STScI). NIRSpec Near Infrared Spectrograph Acknowledgment: Z. Levay. PSF Point spread function QSO Quasi-stellar object (Quasar) RSU Rate Sensing Units (Gyros) 51 ���������������������������Starburst Cluster NGC 3603. NASA, ESA, R. O’Connell (University of Virginia), F. SADE Solar Array Drive Electronics Paresce (National Institute for Astrophysics, Bologna, Italy), E. Young (Universities Space SADM Solar Array Drive Mechanism Research Association/Ames Research Center), the WFC3 Science Oversight Committee, S/N Signal to Noise and the Hubble Heritage Team (STScI/AURA). SED Spectral Energy Distribution SM4 Servicing Mission 4 52 ���������������������������Detail of star-forming region in 30 Doradus in the heart of the Tarantula Nebula. SOHO Solar and Heliospheric Observatory SST Spitzer Space Telescope Please see credits for cover image. ST-ECF Space Telescope - European Coordinating Facility STIC Space Telescope Institute Council 55 ���������������������������Dwarf galaxy NGC 4214. NASA, ESA, and the Hubble Heritage Team (STScI/AURA)- STIS Space Telescope Imaging Spectrograph ESA/Hubble Collaboration. Acknowledgment: R. O’Connell (University of Virginia) and STScI Space Telescope Science Institute the WFC3 Scientific Oversight Committee. TAC Time Allocation Committee TMT Thirty-Meter Telescope UDF Ultra Deep Field 56 ���������������������������Spiral Galaxy M66. NASA, ESA and the Hubble Heritage (STScI/AURA)–ESA/Hubble UV Ultraviolet Collaboration. Acknowledgment: Davide De Martin and Robert Gendler. UVIS Ultraviolet Imaging Spectrograph Subsystem VIMOS VIsible MultiObject Spectrograph 63 ���������������������������Hanny’s Voorwerp. NASA, ESA, W. Keel (University of Alabama), and the Galaxy Zoo VLT Very Large Telescope WFC3 Wide Field Camera 3 Team. WFPC2 Wide Field Planetary Camera 2 64 ���������������������������Detail of the “Mystic Mountain” in the Carina Nebula. Please see credits for image on page iv. 68