Astronomical Instruments on the Moon: Concepts for Fully-Steerable and Survey Vlsts at a Manned Base at the Moon’S South Pole

Home , Kepler (lunar crater), MoonLITE

Lecture 8.2: Astronomical Instruments on the Moon: Concepts for fully-steerable and survey VLSTs at a manned base at the Moon’s south pole

В. Г. Турышев Jet Propulsion Laboratory, California Institute of Technology 4800 Oak Grove Drive, Pasadena, CA 91009 USA Государственный Астрономический Институт им. П.К. Штернберга Университетский проспект, дом 13, Москва, 119991 Россия

Курс Лекций: «Современные Проблемы Астрономии» для студентов Государственного Астрономического Института им. П.К. Штернберга 7 февраля –23мая 2011 LUNAR LASER RANGING Planned NASA Lunar Flight Program

FY08 FY09 FY10 FY11 FY12 FY13 FY14 FY15

Lunar Research and Analysis + NLSI Missions of Opportunity + International Coop. (Science-Funding & Opportunity Driven) Lunar Mapping Project ILN Operation (Goal) Possible International Partner Early Operations C/D E MMM + Mini-RF (Chandrayaan/ISRO) C/D E LRO

BC & DCruis E e GRAIL

SDT Science Definition A BC & D Cruis E e LADEE

SDT Science Definition A B TBDB/C/D during duration Phase finalized A during A E Node I & II Operations Mini Landers Launch date to be set during Phase A 020308 LUNAR LASER RANGING International Lunar Robotic Mission Plans

07 08 09 10 11 12 13 14 15 16 17 18 19 20

NASA

LRO/ LCROSS LSAM Comm/Nav HLR China Change-E Soft Lander Lunar sample return

Mars Lunar Lander/Sample Return ?? sample (NExT) return

Germany/DLR LLO Orbiter Lander ??

India/ISRO Chandrayaan I Chandrayaan 2

Italy/ASI Lunar mission

Japan/JAXA Selene I Selene II Lander Rep. Korea Lunar Orbiter

Russia Luna-Glob Launch Date Final Hardware Delivery UK/BNSC Begin Hardware MoonLITE MoonRaker ?? Development Finalize Agreements LUNAR LASER RANGING ALSEP’s First generation Lunar Network

Lunar Landing Sites

Red=Russian Luna Yellow=Surveyor Green=Apollo LUNAR LASER RANGING Proposed International Lunar Network (ILN)

• International Lunar Network (ILN): – NASA’s SMD is initiating an effort to coordinate future lunar landed missions into an ILN. – The ILN is designed to emplace 6-8 stations on the lunar surface, forming a second-generation geophysical network. – Individual stations could be fixed or mobile. – Each ILN station would fly a core set of instrument types (e.g., seismic, laser retro-reflector, heat flow) requiring broad geographical distribution on the Moon. – Each ILN station could also include additional passive, active, ISRU, or engineering experiments, as desired by each sponsoring space agency. • US-ILN contributions: – The US is committing now to two ILN nodes, launched to the lunar poles, in 2013/2014. – The US is studying the option for a lunar comm relay orbiter enabling lunar far-side access for ILN nodes. – The US is planning a second pair of ILN nodes in 2016/2017. • Next Steps: – 12 March 2008: ILN Informational Briefing to Potential Partner Agencies at LPSC (Houston). Form ILN charter WG. – 20 July 2008: ILN Charter Signing Ceremony (NASA/Ames). Form ILN Landing Site and Core Instrument Definition WGs. – 20 December 2008: ILN Core Instrument Agreement. ASTRONOMICAL INSTRUMENTS ON THE MOON Outline

• The trends in building telescopes • Possible locations for future observatories – Antarctica, Dome C – The Moon – South Pole of the Moon •Prosfor astronomical instruments on the moon – Interferometers and telescopes on the moon – Optimistic scenario for astronomy from the moon – Examples of proposed instruments • Cons against astronomy from the moon – Comparative environments – Technologies needed, advantages and disadvantages – Realistic scenario for astronomy from the moon ASTRONOMICAL INSTRUMENTS ON THE MOON Telescopes over past 50 years

• Space – From sounding rockets to great observatories – Each successive mission is uniquely powerful – Typically scientific and failure lifetime ≤10 yr – Hubble exception • Ground – Not much size increase – Huge increase in power by better detectors, multiplexing and adaptive optics – Long-lived, rejuvenation on ~ 5-10 year timescale as science goals and technology change ASTRONOMICAL INSTRUMENTS ON THE MOON Lifetimes of Current Generation Space Observatories

Observatory Spectrum Dates Life Orbit Lifetime set by Compton gamma 1991‐2000 9 LEO Gyro failure Hubble optical 1990 – 2005? 15? LEO Gyro failure, orbit decay; +5? Final servicing Aug. 28, 2008 Chandra x‐ray 1999 – 2013? 14? elliptical Gyro failure? Spitzer infrared 2003 ‐ 2009 2.5 Drift Cryogen exhaustion away Webb infrared 2015 ‐ 2025 10 L2 Fuel to maintain L2 orbit ASTRONOMICAL INSTRUMENTS ON THE MOON Next 50 years on ground (you must put future space plans in this context)

Several telescopes in 20 – 100 m range • Adaptive Optics (AO) should mature to give all sky diffraction limit at 0.5 mm, especially if placed on • Antarctic plateau (L2 of ground)

– 25 m in Antarctica (Giant Magellan Telescope II) would rival JWST for spectroscopy – 100 m in Antarctic for terrestrial exoplanets • detection at 10 mm • spectroscopy in optical ASTRONOMICAL INSTRUMENTS ON THE MOON AO will work well in Antarctica

Atmospheric turbulence mostly at low altitude, unlike temperate sites

1E-14

DomeDCI C - I 1E-15 DomeDCIII C - III )

-2/3 1E-16

(m.s Mauna Kea 2 MK N C

1E-17 Dome CDCII – II (AO)

1E-18

10 100 1000 10000 Height Above Ground Level (m) Atmospheric turbulence profiles projected for Dome C by Lawrence et al (2003). ASTRONOMICAL INSTRUMENTS ON THE MOON Thermal environment is good in Antarctica

… though 10 micron background 105 higher GMT and JWST point source sensitivity for l>2.5 mm, 10s, 105 sec ASTRONOMICAL INSTRUMENTS ON THE MOON Next 50 years in Space, beyond JWST

• Unique space attributes are – No atmospheric absorption in UV, thermal IR – Pristine wavefront – No thermal emission if optics cold • Large, cold telescopes will outperform ground in UV/ thermal IR • Very big space telescopes – with huge capital investment, like on ground telescopes should have multi decade lifetime, and be refitted every decade ASTRONOMICAL INSTRUMENTS ON THE MOON Requirements for Location & Possibilities

• Far from Earth, to avoid its thermal radiation (for thermal telescope) • Accessible by astronauts as well as robots •LEO – Easiest for astronaut access – Warm, thermal cycling, reduced duty cycle – Re-boosts needed to maintain orbit •L2 – Cold, all sky access with 50% duty cycle – Hardest for astronaut access – Expendable fuel needed to maintain orbit – Pointing gyros subject to failure • Moon S pole – Cold, 100% duty cycle for 50% of sky – If base established, astronauts are nearby – No expendables needed, no gyros – 3 x mass penalty if no established base ASTRONOMICAL INSTRUMENTS ON THE MOON The Longer the Better…

• Requirements for Longevity – Stable orbit – avoid LEO and L2 – No gyros – No expendable cryogens – Provision for occasional repair and upgrades by astronauts – Long life against radiation damage

• If our telescope is a million miles away, we may have trouble getting astronauts to visit. • But if they are at a long term moon base, we should think about locating our telescope nearby ASTRONOMICAL INSTRUMENTS ON THE MOON The Moon as a Telescope Site

• Basics are fine – All wavelengths accessible, vacuum of space – Orbit stable on billion year timescale – Telescopes can be “safed” for decade and then brought back to service • Moon’s spin axis 1.5 degrees from ecliptic pole – Sun moves around within 1.5 degrees of horizon – Very low temperatures by simple shielding of sunlight • 3x mass penalty to descend from lunar orbit – No air braking, as for Earth and Mars; requires rocket – Apollo vehicle and fuel weighed 2½ times the payload mass delivered to surface – 18.3 tons rocket carried a payload of 7 tons (the fueled ascent stage and crew) ASTRONOMICAL INSTRUMENTS ON THE MOON Needs a Lunar Polar Base

• Telescope on moon makes sense if there is a long term, manned polar base • Why the pole? – Frozen volatiles in permanently dark, cold craters – Ice can be recovered from regolith in craters – Ice converted to hydrogen/oxygen fuel by locally produced by solar power – Cryo storage of fuel – Reusable ferry vehicle from surface to lunar orbit powered by local fuel - removes mass penalty ASTRONOMICAL INSTRUMENTS ON THE MOON Needs Astronauts!

• Polar base astronauts will need range of skills: – Install and maintain mining gear. Need to get > 0.5 km down 45 degree slope below crater rim to get permanently-shadowed ice- containing regolith – Install and maintain water extraction, photolysis and fuel storage equipment – Maintain reusable rocket ferry – Maintain atmospheric conditioning equipment • Grow plants using local water

• Given these capabilities, assembling and maintaining 20 m telescopes would be present little additional challenge ASTRONOMICAL INSTRUMENTS ON THE MOON ASTRONOMICAL INSTRUMENTS ON THE MOON The Lunar South Pole-Aitken Basin

. The South Pole-Aitken Basin is the biggest, deepest impact basin in the solar system; . This view is centered at 56°S, 180°E. . The rim crest D~2500 km; to ~13 km in depth; . Average depth is about 10 kilometers.

Possible Future Base Site: . Cold traps with water . Solar illumination . Stable temperatures (~220±10K) 19 ASTRONOMICAL INSTRUMENTS ON THE MOON Ice at south pole

Ice at south pole as measured by neutron flux (Lunar prospector) ASTRONOMICAL INSTRUMENTS ON THE MOON Possible Lunar Locations

South Pole Region of the Moon:

Malapert Mountain

21 ASTRONOMICAL INSTRUMENTS ON THE MOON LATOR Architecture on the Moon

Benefits of The Moon: . No atmosphere (10-9 Earth) . Stable platform [orbit to 1 cm] . Seismic activity 8 orders less . ~98% solar illumination . Temperature 220±10K

Unique features: . Longer baseline ~ 1km . Free-space laser Accuracy for  ~1 ppb

The Mission will Need: . Lander [JPL] . Rover [JPL] . RTG [LANL, Teledyne] 22 ASTRONOMICAL INSTRUMENTS ON THE MOON Shackleton Crater (South Pole)

Lunar Surveyor 1967 image of Shackleton crater (18 km diameter) ASTRONOMICAL INSTRUMENTS ON THE MOON Shackleton Crater (South Pole) Sunshine available for nearly continuous solar power.

Clementine map for lunar winter ASTRONOMICAL INSTRUMENTS ON THE MOON Typical Lunar Possibility

Surrogate crater Dionysius • Typical 18 km crater, but illuminated • Sharp rim ASTRONOMICAL INSTRUMENTS ON THE MOON Dionysius Rim Close-up (for Shackleton ice >500 m from rim) ASTRONOMICAL INSTRUMENTS ON THE MOON Typical Cross Section of 18 km Crater ASTRONOMICAL INSTRUMENTS ON THE MOON Telescopes at South Pole

Don’t need to be in crater to be cold • Locate on rim far enough from base to avoid dust • Sun moves around horizon, simple aluminized surrounding cylindrical screen will result in cooling to 40K or less

– Lower screen to warm up for repairs

• Three UV/O/IR flavors considered here

– Fully steerable 16 m – 20 m zenith pointing ultra-deep survey filled aperture – Zenith-pointing wide-field interferometer ASTRONOMICAL INSTRUMENTS ON THE MOON Pierre Bely’s 1990 Concept for 16 m Lunar Telescope • Hexapod mount • 6 variable length legs pre- manufactured on Earth •low mass • no heavy foundation or bearing surfaces required • No gyros • Instruments shielded under regolith igloo • Advantage over L2: – No gyros, no fuel for orbit correction – Astronauts nearby ASTRONOMICAL INSTRUMENTS ON THE MOON Sky Coverage for the Lunar South Pole

• S pole lunar telescope sees same southern sky as Antarctic telescopes • Most terrestrial planet candidates < 5 pc visible from lunar South Pole!

Star Ecliptic latitude type V mag distance parallax notes Alpha Cen ‐43 G2 0.0 747 K0 companion Eps Eri ‐27.7 K2 3.7 310 Jovian planet? Lacaille 9352 ‐27.5 M 1.5 7.3 304 single Eps Indi ‐41.4 K5 4.7 276 Two T dwarf companions Tau Ceti ‐24.8 G8 3.5 274 single Kapteyn’s star ‐67.5 M1.5 8.8 255 single AX Microscopium ‐21.9 M0 6.7 253 single GJ 674 ‐23.6 M3 9.4 220 single GJ 832 ‐32.47 M3 8.7 198 single ASTRONOMICAL INSTRUMENTS ON THE MOON Zenith-pointing Interferometers & Telescopes

• Zenith traces out 3º degree diameter circle adjacent to LMC, over 18 year period • Fixed telescope, optics to steer field 1.5º off-axis, 6 degree field accessible • Could use optics panels from Earth, or liquid mirror

• Zenith-pointing interferometers: – Fizeau combination (wide field) will work well with no moving parts Ecliptic pole imaged in uv from moon – Moon rotation ideal for zenith by Apollo astronauts. 6 degree circle observation around ecliptic pole ASTRONOMICAL INSTRUMENTS ON THE MOON 20 m Liquid Mirror Telescope on Superconducting Bearing

• Lunar liquid mirror telescope proposed by Borra ~ 1990 • Unique to Moon – needs gravity • 2 rpm for 20 m focal length • Use with liquid of low vapor pressure, vacuum deposited metallic coating (1-butene) • 20 m aperture on same field 24 hr/day for a year • This is the ultimate deep field • Imaging and multi-object spectrograph Roger Angel: Spinning telescope on the Moon! ASTRONOMICAL INSTRUMENTS ON THE MOON Estimates for first stars in this deep field

• From Eisenstein and Gillespie • Lyman alpha flux to be about 1 nJy at z=25 and R=1000 for a 100 M star. • Scales linearly with the star's mass • Equivalent photons for neutral helium can't pass through the IGM • Individual stars should be imageable in HeII line at 1640 A • Flux about 10% of the Lyman alpha line (i.e. 0.1 nJy) ASTRONOMICAL INSTRUMENTS ON THE MOON Spinning Liquid Mirrors on Earth • Spinning liquid mirrors on Earth limited to ~ 6 m by self-generated wind • No such size limit on Moon

Roger Angel: Spinning telescope on the Moon! 6 m, zenith pointing spinning mercury mirror, by Paul Hickson Comet image from earlier prototype above ASTRONOMICAL INSTRUMENTS ON THE MOON Conclusions

• For 20 m class space telescopes, longevity of decades highly desirable • Possibility of astronaut access for assembly and robot back-up also highly desirable • If a long term polar moon base is established, then an observatory nearby makes a lot of sense • Locally fueled ferry to lunar orbit will remove mass penalty • Long term base only tolerated if operating cost <1/4 NASA budget (< $4B/yr), say 1 visit/year ASTRONOMICAL INSTRUMENTS ON THE MOON Key Strategic Questions

• What scientific questions are ripe for the next few decades? • What scientific questions are worth the money to do in space? • Site surveys: advantages of the lunar surface and free space? • Robots or astronauts: which goals need which systems? • For given requirement, what are cost differences between sites? • How much does it all cost? ASTRONOMICAL INSTRUMENTS ON THE MOON Possible Hardware for Human Space Exploration

• Orion (Crew Exploration Vehicle, CEV, under design/ construction) • Ares 1 (Crew Launch Vehicle, CLV, under design/ construction) • Ares 5 (Cargo Launch Vehicle, CaLV much larger) • Lunar Surface Access Module (LSAM) • Earth Departure Stage (EDS, cryo upper stage of Ares 5) • Advanced space suits ASTRONOMICAL INSTRUMENTS ON THE MOON Hardware (2)

• Advanced servicing capabilities – Remote robotic – Local astronaut-controlled robots/manipulators – EVAs • Advanced habitat equipment – Astronaut safety: centrifuges, shields, possibly from local materials – Life support: food production, recycling – Solar and nuclear power and communication – Service stations at Earth-Moon L1, Sun-Earth L2 (later) ASTRONOMICAL INSTRUMENTS ON THE MOON Hardware Enabling New Astrophysics

• CEV and CLV, under design for construction – New sites on Moon – Servicing at new locations not on Moon • Advanced servicing capabilities - TBD, very important to astrophysics – Very remote robotic (e.g. operated from ground) – Local astronaut-controlled robots/manipulators – EVA - depends on airlocks and many details • Ares 5 (Cargo Launch Vehicle, CaLV) – Larger payloads, farther away or faster • Advanced habitat development – Solar and nuclear power and communication – Service stations at Earth-Moon L1, Sun-Earth L2 (later) ASTRONOMICAL INSTRUMENTS ON THE MOON Important Astro- & Solar System Physics from the Moon

• Lunar geology:

– sample recognition, analysis, excavation, return to Earth • Lunar structure:

– mapping, gravity, surface and interior chemistry and physics • Lunar origin • Solar system archeology, by interpretation of samples • Laser ranging from Earth, to test Einstein ASTRONOMICAL INSTRUMENTS ON THE MOON Payload Mass

• For JWST, launch vehicle cost ~ 3-4% of life cycle cost, but launcher imposes strict mass limit • If same mass were landed on the Moon, would need ~ 3x launcher capability, perhaps rocket cost would scale in proportion? • Cost estimation algorithms for observatories say cost and mass are ~ proportional, so 6000 kg is about the maximum for a JWST-class telescope anywhere

– Does this apply to observatory alone, or including landing equipment? ASTRONOMICAL INSTRUMENTS ON THE MOON Stiffening a Big Telescope for 1/6 g

• No way to make a passively stable system highly precise, ==> need active control loops re-adjusted for each elevation angle • Like adaptive optics on ground, but much slower - OK but complicated • Strength not an issue, since launch loads are much larger • For R. Angel concept of spinning liquid mirror, gravity is required, but there is no possibility of changing its axis from vertical. ASTRONOMICAL INSTRUMENTS ON THE MOON Dust

• Lunar dust is hazardous - sharp, small, sticky, covers astronauts, requires cleaning to get vacuum seals on suits • Lunar dust levitates due to electrostatic forces, seen by astronauts as a haze • Laser retroreflectors may be contaminated by dust - more info needed • A serious engineering challenge to manage dust around telescopes ASTRONOMICAL INSTRUMENTS ON THE MOON Optical Interferometers

• On Earth or Moon, complicated optical systems with path length equalization systems and huge rooms filled with trolleys and mirrors • Servicing might be necessary - ground based equipment is hard to adjust • Free-space version optically much simpler

– Path equalization by formation flying – May still need servicing? ASTRONOMICAL INSTRUMENTS ON THE MOON Radio Telescopes

• Long wavelength (> 30 m) needs space • Very little is known in this band, wide open for exploration and surprise, but so far not recognized by NAS as top scientific priority

– New generation ground-based observatories will allow extrapolation from higher frequencies • Need large array of dipoles to image large areas of sky • High angular resolution needs huge array

–  = /d – 1 arcsec at 30 m means 6000 km span • Reconfigure array to match required  • TBD how quiet the environment must be ASTRONOMICAL INSTRUMENTS ON THE MOON Servicing Possibilities

• Lunar surface advantages – Can’t get lost on lunar surface, but must travel by car or on foot – Tools can’t escape – Astronauts could have permanent safe home (far future), always available to service complex observatories • Free space advantages – Can be anywhere the telescope is, or can go • LEO to EM L1 to SE L2 to … – Equipment is weightless - no lifting fixtures – No dust to contaminate telescope & tools – Extensive experience with HST, Space Station – Astronauts can come home from EM L1 in a flash if bad solar weather ASTRONOMICAL INSTRUMENTS ON THE MOON Site Survey: the Moon and Free Space (e.g. L2)

Item Lunar Surface Free Space (e.g. Sun -Earth L2)

Delivered payload mass per launch ~ 1/3 (depends on Isp of propulsion, many details) 1 (implies launch cost difference) Gravity g/6, causes sag of optical system vs. pointing, needs stiff 0 structures, added mass. Enables spin-formed parabolic mirror with vertical axis (R. Angel, P. Worden) Servicing, repair, upgrade Six Apollo missions; 1969 -- 1972; few days trip each way, Shuttle missions for HST, ISS, CGRO; limited radiation exposure to astronauts. robotic arms; numerous robotic designs. Sun- Earth L2 much farther from Earth than Moon. Possible service center at Earth-Moon L1. Dust Sticky, small, charged, naturally levitated above surface; 0 activated by astronauts, rovers, and retrojets; seen by astronauts; evidence of accumulation on retroreflectors Solar power duty cycle 14 days/29, except polar peaks (1) or dark craters (0), may 1 require storage for lunar night Communications duty cycle 1 on front, needs relay on backside or deep crater 1 Temperature variation of Variable solar direction (except in dark craters) requires Constant solar direction permits simple environment complex sunshield designs sunshield designs. Observing duty cycle Depending on stray light shields, power, thermal protection 1 and stability, and comm Field of Regard Depends on lunar latitude and horizon shape inside thermal Whole sky shields Interferometer baseline Passive, can’t get lost. Fixed positions, or movement across Active servos, full (u,v) coverage. Requires maintenance challenging terrain station keeping and propulsion. Path length compensation Long range (comparable to spacing of collectors), to obtain Short range (few cm), as part of formation field of view and (u,v) coverage flying servo control loop Maximum baseline Size of flat region on Moon Optics limited, huge

Radio quiet Far from Earth; back side is protected for now Can be much farther from Earth ASTRONOMICAL INSTRUMENTS ON THE MOON Possible Servicing Uses

•CEV – How far can it go to do servicing? – Quick astronaut trip to SE L2? (too risky if EM L1 would be enough, but maybe later…) • Robotic servicing, e.g. using astronaut tools and manipulator arms, to reduce risk or enable upgrades – Beyond Einstein probes - servicing probably not needed, but …? – Interplanetary missions, robot explorers? – Future Great Observatories

• Chandra, LISA, SIM, TPF-C, TPF-I, TPF-Occulter, SAFIR… ASTRONOMICAL INSTRUMENTS ON THE MOON Future Large Observatories: Decadal Survey

• Chandra X-ray observatory

– Lunar surface bad for very precise optics, free space good, servicing possibly valuable • LISA gravity wave observatory

– Lunar site impossible, remote servicing possible by replacing a member of the triangle with a new one (no robot or astronaut visit needed) • SAFIR far IR telescope

– Lunar surface much too hot except possibly in dark crater - don’t know this yet, need ~ 4 K cooling for ~ 10 m telescope • SPECS and SPIRIT, far IR interferometers

– ~ 4 K telescopes at all possible spacings in (u,v) plane – Lunar surface not possible - too hot, telescopes not mobile ASTRONOMICAL INSTRUMENTS ON THE MOON Planet Finders

• Kepler: transit search, 2008 launch

– Continuous monitoring of Cygnus region, declination ~ 40o +/- 23o – Dark crater at North lunar pole? target elevation ~ 40o +/- 23.5o • Microlensing Planet Finder (Discovery proposal)

– Requires continuous monitoring of Galactic Center – GC is in Ecliptic Plane, ~ on horizon from Lunar poles • Nearest Star Planet Transit Survey (extends ground-based surveys with better photometry)

– Like Kepler, but all-sky survey, to find nearest and brightest, best candidates for follow-up by JWST, etc. – Lunar pole locations possible; need 2 for all-sky ASTRONOMICAL INSTRUMENTS ON THE MOON Planet Finders (2)

•SIM

– Requires complete thermal stability and wide sky view – Dark crater potential site, but loses > half of targets • TPF-Coronagraph

– Lunar surface probably impossible - optical system must be /3000 and perfectly stable, and extremely clean (no dust at all!) • TPF-Interferometer

– Lunar surface probably impossible - but worth some study – Filling (u,v) plane much easier in space than on surface of Moon • New Worlds Observer - remote occulter

– Lunar surface impossible - formation flight configuration with ~25,000 km spacing ASTRONOMICAL INSTRUMENTS ON THE MOON What would I do?

• Coordinate with manned program to assess capabilities needed by both manned program and science • Understand approach of manned program to manage dust, and what equipment and infrastructure they will develop and when • Study how much dust contaminates lunar optics, and how to mitigate it • Study how to design astronomical equipment ON Moon – AFTER manned program is defined, lunar sites and habitats are selected, and infrastructure is known – Lunar Astronomy is NOT a driver for the manned program - plenty of other ways, currently easier, to do science • Present to NAS review for comparison to other sites • Offer new observing sites and infrastructure in competitive AO’s for science • Astronomers are ingenious: they’ll find a way to use the infrastructure or the lunar surface! ASTRONOMICAL INSTRUMENTS ON THE MOON In the meantime

• Assess possible augmentations to Exploration Architecture with joint benefits to science and manned program • Study potential radio astronomy at  > 30 m: does it justify space equipment? • Study (with AAAC) what equipment matches the scientific goals for exoplanets - if very complex or risky, servicing may be appropriate • Study (with NAS) what has priority in next decade for space and ground-based astronomy

– If top priorities could benefit from the VSE infrastructure, do needed studies ASTRONOMICAL INSTRUMENTS ON THE MOON Summary and Conclusions

• Exploration Architecture & infrastructure (heavy lift vehicles, CEV, robotic servicing) could enable much more powerful large observatories, in free space, with much longer useful lifetimes, than are possible today • Since we’re going to the Moon, then study the Moon itself • Lunar surface not best use of money for most telescopic astronomy, but when manned program is defined, then offer lunar sites and infrastructure in AO’s • Astronomy is NOT a driver for manned program requirements - too many other ways to do most science, and conflicting program requirements drive up costs • For specific science, e.g. gravity studies by laser retroreflector, lunar placement is very important • Need to know whether (expensive, fragile) human presence is required on-site for astrophysics missions ASTRONOMICAL INSTRUMENTS ON THE MOON LUNAR LASER RANGING Lunar Science Robotic Mission Initiative

“It is the unanimous consensus of the (NRC) committee that

the Moon offers….A vigorous profound scientific value. near term robotic exploration program providing global access is central to the next phase of scientific exploration of the Moon and is necessary both to prepare for the efficient utilization of human presence and to maintain scientific momentum as this major national program moves forward.”

-The Scientific Context for Exploration of the Moon, National Research Council, LLR provides answers to all of these questions Space Studies Board, 2007.

Alan Stern, presentation @ LPSI on 12 March 2008