Map out nearby planetary systems and understand the diversity of the worlds they contain. Seek out nearby worlds and explore Open up new windows on the their habitability. universe from the UV through near-IR. Habitable Exoplanet Observatory (HabEx) A starshade-only alternative David Redding, Keith Coste, Otto Polanco, Claudia Pineda, Kevin Hurd, Howard Tseng, Stefan Martin, Rhonda Morgan, Kevin Schulz, Jonathan Tesch, Eric Cady (JPL), Michael Rodgers (Synopsis), Matthew East, James Mooney (Harris), Christopher Stark (STScI), Gordon Wu, Bradley Hood (Ball Aerospace) Pre-Decisional Information -- For Planning and Discussion Purposes Only © 2019 California Institute of Technology. Government sponsorship acknowledged. Fitting HabEx Science into the $3-5B Cost Box • Implement the HabEx mission concept using only a Starshade for exoplanet imaging – no coronagraph • Provides the highest quality exoplanet imaging and spectroscopy capabilities • Supports the full HabEx General Astrophysics program • But – lowers exoEarth yield, as fewer total target systems can be observed • Eliminating the HabEx coronagraph simplifies the mission to reduce cost: • Removes a complex optical instrument • Relaxes observatory wavefront stability requirements >100 times • Permits a compact, on-axis telescope design that fits into a lower-cost launch vehicle (Vulcan Centaur, Delta IV Heavy, e.g.) • Permits use of a lower mass segmented mirror, whose manufacture is within the current state of practice • Lowers overall Observatory mass including margin to <10,000kg • Consider decreasing aperture diameter • HabEx 3.2 S (with D=3.34m) has been our study focus, with costs <$5B • HabEx 4 S fits in the same envelope, and may also be < $5B 2 jpl.nasa.gov Pre-Decisional Information -- For Planning and Discussion Purposes Only HabEx Starshade-Only Architecture HabEx would... Seek out nearby worlds and explore their habitability. Scarfed barrel for Map out nearby planetary systems and understand pointing 40 deg the diversity of the worlds they contain. towards the Sun Open up new windows on the universe from the UV Reclosable cover through near-IR. for contamination Key Mission Requirements control Stowed Parameter Value Antenna Aperture diameter 3.2 to 4 meter Bandpass 115–1,700 nm Operating temperature ≥270K Solar Diffraction limit wavelength 400 nm Arrays General Wavefront error, total ≤30 nm rms Pointing accuracy 2 mas/axis Radiator Pointing stability 2 mas/axis Panels Raw contrast ≤10^-10 from IWA Inner Working Angle (IWA) <74 mas Serviceability Instruments Spectroscopy resolution R ≥ 7 (300–450 nm) Door R ≥ 140 (450–1,000 nm) Exoplanet R ≥ 40 (1,000–1,800 nm) Payload Barrel Waveband, imaging 150-1,700 nm Interface Waveband, spectroscopy 350-1,400 nm Plate Field of View 3x3 amin Propellant Camera Camera Workhorse Workhorse Tanks Spectral resolution R ≥2 ,000 Spacecraft Waveband 115-300 nm Bus UV UV Field of View 2.5x2.5 amin graph Radiators - Spectro Spectral resolution R = 1 to 60,000 Thrusters Waveband, imaging 300-1,700 nm Waveband, spectroscopy 300-1,700 nm Startrackers Field of View 8x8 asec Camera Camera Starshade Starshade Spectral resolution R ≥2 ,000 3 jpl.nasa.gov Pre-Decisional Information -- For Planning and Discussion Purposes Only HabEx Starshade Ops Require Two Launches 4 jpl.nasa.gov Telescope Uses Active Optics for Assured Performance SSS SMA SMA: Secondary Mirror Assembly SM: Secondary Mirror PMA: Primary Mirror Assembly SM PM: Primary Mirror RBA: Rigid Body Actuators FCA: Figure Control Actuators SMS AMS: Aft Metering Structure SSS: Secondary Support Structure SMS: Secondary Mirror Struts PIP: Payload Interface Plate Actuator Honey Dipper Flexures (6) RS PMA (Reaction Structure) AMS Actuator Shaft Support Struts Mirror Segment Instruments Electronic Boxes PIP Requirement 18.0 nm rms WFE Nominal Corrected Margin 8 nm • Wavefront Sensing and Control establishes 56.0 16.0 nm initial 30 nm RMS WF error Nominal Corrected Segment Figure 108.0 12.0 nm • Rigid-body control of PM segments and SM Includes effects of polishing, testing, gravity sag prediction, temperature change, coating, and phase and collimate the telescope matching radius of curvature • PM segment figure control assures Nominal Corrected Mounting Errors 26.0 10.0 nm performance while relaxing fabrication reqts. Includes effects of bonding mounts and devices, material creep, desorption, etc. • Laser Metrology is used to continuously maintain optical alignments 5 jpl.nasa.gov ULE Mirrors: Demonstrated Performance • MMSD low mass: 10 kg/m2 •Prefer 20 kg/m2 for HabEx B • WF error: •15 nm RMS WFE stand-alone, with backouts •8 nm WFE RMS post-actuation predicted • Survivability tested to high level • Random vibe and shock 6 jpl.nasa.gov Harris Capture Range Replication • Capture Range Replication uses precision mandrels and low-temperature slumping to replace traditional generate- grind-polish processes Flat Polished Plates LTF Flat Mirror CRR Mirror Flat ULE Flat Grind & Plates- Front Polish • CRR finishes a mirror blank to and Back Capture Assemble within capture range for final Range MRF or Ion and LTF Final Test Replication Finishing Mirror finishing (MRF or Ion Beam) (CRR) Flat ULE AWJ Flat Grind & Plates- Lightweight Polish • Result is a repeatable, efficient Cores Cores process for mirror fabrication, saving time and cost Large Optics w/ Deterministic Finishing Replication e e l l u u d d Ion e e h h MRF c c S S CRR mirror finished under IRAD funding Custom Tooling / / t t High Labor Content s High Precision Mandrel s Non-Deterministic o o Mandrel Test Set C C Replication Risk Management Generate Grind Polish Finish Precision Precision Capture Range Replication (CRR) leverages the strengths of replication to eliminate the high cost/ schedule processes in optical fabrication to provide an optimized solution HabEx Instruments, Minus the Coronagraph TwTwoo--MiMirrrror Telleessccooppee HabEx Workhorse Camera HabEx Starshade Instrument Field 1 Field 2 UVS Field 3 Field 4 And And And Or Imager UV Spectrograph Starshade Spectrograph (external) Imager R = 2000 Microshutter And And Microshutter Array Array Or Or Or Grating Set Guide Grism Or R=1, 500, 1000, Imager Or Filters Grisms 3000, 6000, 12000, Channel R = 7 Guide Imager 24000, 60000 Channel Or VIS IFS IR IFS VIS Camera IR Camera 450-1000 nm 975-1800 nm UV Detector VIS Detector IR Detector UV Detector UV Detector 450-1000 nm 975-1800 nm 320-450 nm 450-950 nm 950-1800 nm 115-300 nm 200-450 nm R=140 R=40 • Two-mirror telescope is designed to minimize the number of bounces into the UV instruments • Starshade Instrument (SSI) provides spectroscopic and guider modes in the UV, VIS and NIR bands • UV Spectrograph (UVS) provides high-resolution spectroscopic, photometric and imaging modes in the 115-300 nm band, to cover a 3 amin field • HabEx Workhorse Camera (HWC) provides imaging, photometric and spectroscopic modes in the UV, VIS and NIR, covering a 3 amin field 8 jpl.nasa.gov Starshade Instrument (SSI) For high contrast observations and SS guiding To seek out nearby worlds and explore their habitability. To map out nearby planetary systems and understand the diversity of the worlds they contain. From the telescope UV imager VIS imager FPA FPA Vis IFS FPA IR IFS FPA Prism PIL IR imager Vis IFS PIL FPA • Starshade Instrument has 8 modes, lenslets covering the full λ=200-1800 band in the IR IFS lenslets Selector same 8x8 asec field. mirrors • 3 star imaging (UV, Vis and IR), • 2 IFS (Vis and IR) • 1 spectrograph (UV) • 2 pupil imaging for guiding (UV and IR) 9 jpl.nasa.gov HabEx3.2S Starshade Imaging Performance Sunshade contrast Our solar system as seen face on from 10 parsec by Contrast, λ=300nm HabEx3.2S + Starshade -150 FoV = 8x8 arcsec, λ = 400-700 nm -100 1x zodiacal dust -50 0 Saturn 50 Contrast Venus HabEx Starshade fromAnglestar(mas) Jupiter 100 Diameter 52m Earth Petal Length 16m 150 Minimum F 8.8 Baseline (VIS) Mode Contrast, λ=1000nm Bandpass 300-1000nm -150 IWA0.5 58 mas Distance 76,600 km -100 Glint from SS UV Mode, small IWA -50 edge Bandpass 200-667nm IWA0.5 39 mas 0 Distance 114,900 km 50 Contrast Starshade IR Mode, large IWA outline Angle fromstar(mas) Angle Bandpass 540-1800nm 100 IWA 104 mas 0.5 150 Stellar Distance 42,600 km leakage Credit: S. Hildebrandt, S. Shaklan • Starshade provides a range of observational capabilities, all with high contrast • Recent lab results (J. Kasdin et al) demonstrate <1e-10 SS contrast performance 10 jpl.nasa.gov Starshade-Only CONOP and Yield HabEx 4H HabEx 4S HabEx 3.2S Architecture: 4-meter Hybrid 4-meter SS-only 3.2-meter SS-only • SS-only CONOP: Exoplanet Yield: Exo-Earths: 8 5 4 • Spectrally characterize all Rocky: 55 29 23 discovered exoplanets Mini-Neptunes: 60 48 40 Giants: 63 63 56 • Return 3x to measure orbits Effective Collecting • SS-only exoplanet yield could Area (휆=200 nm): 14X HST 18X HST 12x HST be increased, up to ~2x: Spatial Resolution • By precursor RV surveys (휆=400 nm): 25 mas 25 mas 30 mas sensitive enough to identify Number of TRL 4 promising targets technologies: 11 7 7 • By RV follow-up to measure orbits • By refueling the SS, to give it longer life and more observations • By flying another SS • By increasing aperture size • SS-only astrophysics and solar system science also would benefit if aperture is increased 11 jpl.nasa.gov UV Spectrograph To probe the lifecycle of baryons by determining how the gaseous processes at work in the IGM and CGM drive galactic evolution. To probe the physics governing star-planet interactions by investigating auroral activity on gas- and ice-giant planets within our solar system. Relative Transmission of Hi-Resolution UV Spectrographs 400200 4.0 5-bounce HabEx 150 4.0 300 7-bounce HabEx 3.2 5-bounce HabEx 200100 COS FUV 90-215 nm 10050 COS NUV 170-320 nm 00 90 140 190 240 290 340 • A high-throughput, 5-bounce spectrograph, with 3 amin FOV • Covers λ=115-320 nm waveband • Spectral modes with R = 500, 1000, 3000, 6000, 12000, 24000 and 60000; plus imaging and photometry • Microshutter array for multiplexed source selection and spectroscopy 12 jpl.nasa.gov HabEx Workhorse Camera To understand and trace the origin of the elements from the first stars until today.