LCROSS Mission Overview & Results (


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Overview talk about NASA's LCROSS Mission that provided an impact experiment to search for water within a permanently shadowed region at the lunar pole. Secondary payload, low cost, active risk management, successful. Mission ended Oct 9, 2009. The "impact" of the impact is rewriting science and exploration of our nearest neighbour.

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  • Neutrons are produced in lunar surface by galactic cosmic rays interacting with nuclei in lunar materials. Hydrogen is good at removing energy from neutrons. Area of high-Hydrogen <-> low epithermal neutron counts. The dark blue and purple areas indicate low counting rates and are consistent with hydrogen-rich deposits covered by desiccated regolith. Explanation: Hydrogen acts as a excellent “neutron tracer” since mass of H is similar to that of a neutron. Neutrons are produced in lunar surface by galactic cosmic rays interacting with nuclei in lunar materials. This interaction produces HIGH-energy neutrons (>100skeV) which are scattered away & lose energy with each scatter. The hydrogen nucleus is good at removing energy from neutrons. So in areas of HIGH HYDROGEN, neutrons of low energy (epithermal) will BE DEPLETED (less of them) than in areas of low-hydrogen.
  • Impactors range in mass from 100 g to 1000 kg Current meteoroid models indicate that the moon is struck by a meteoroid with a mass greater than 1 kg (2 lbs) over 260 times per year The slowest impact velocities are 20 km/sec (4500 mph) The fastest impact velocities are over 72 km/sec (160,000 mph) At such speeds even a small meteoroid has incredible energy -- one with a mass of only 5 kg (10 lbs) can excavate a crater over 9 meters (30 ft) across, hurling 75 metric tons (165,000 lbs) of lunar soil and rock on ballistic trajectories above the lunar surface.
  • (b) Centaur impact’s actual location derivation by multiple approaches on a 500 m x 400 m grid (Note: meter scale). North/South runs along vertical axis. The target supplied by the science team is placed at origin (large blue X). Estimates using trajectory propagation are shown by orange triangles. Their 1-  errors are represented by large orange circle (156 m radius). Magenta squares are bundle-adjusted image registration against LOLA terrain. Forward propagation from S-S/C trajectory using LCROSS MIR1 imagery produced the green diamonds. Their 1-  errors are shown by green ellipse 3 m by 75 m (semi axis). Vectors to Sun and Earth are shown. Inset at lower right shows comparison of S-S/C impact location, derived from trajectory analysis, to its planned target location.
  • LCROSS Mission Overview & Results (

    1. 1. LCROSS “the lunar hitch-hiker that made an impact (literally!) on how weview our Moon and its science secrets” Dr. Kimberly Ennico (NASA Ames Research Center) poses with LRO (silver), LCROSS (gold), Astrotech, Titusville, FL, May 2009)
    2. 2. a glance...Launch: June 18, 2009 Impact: October 9, 2009 (LCROSS was required to meet a 28 month, ATP to launch, schedule, and to have minimal impact to LRO development and launch.)
    3. 3. Why LCROSS? Mission Primary Objective:To test whether ornot water ice depositsexist on the Moon. (Classic Scientific Method)
    4. 4. Why Look for Water?• Humans exploring the Moon will need water: – Option 1: Carry it there* – Option 2: Use water that may be there already• Learning to “Live off the land” could make (long-term) human lunar exploration easier. (*At $10K/lb to orbit. $3-5K more to Moon. At 8 lbs/gallon, it could cost >$100,000/gallon of water to the Moon.)
    5. 5. Early Evidence of Water Clementine Lunar Prospector (1994) (1999)Two previous missions, Clementine and LunarProspector gave us preliminary evidence that theremay be deposits of water ice at the lunar poles.
    6. 6. Controversial: ice or rough terrain? Clementine bistatic radar – 1994 Ref: Nozette, S. et al. Science 274, 1495-1498 (1996)• Circular polarization ratio (CPR) consistent with ice crystals in the south polar regolith.• Ground-based studies (Arecibo) confirmed high-CPR in some permanently- shadowed craters. – However, Arecibo scans also found high-CPR in some areas that are illuminated, probably due to surface roughness. Ref: Stacy, N. et al. Science, 276, 1527-1530 (1997)
    7. 7. Accepted, not conclusive re: ice Lunar Prospector – Hydrogen 1998 Ref: Feldman, W.C. et al. Science 281, 1496-1500 (1998)Map courtesy of D. Lawrence, Los Alamos National Laboratory.• Neutron spectrometer maps of both lunar poles• Low resolution data indicate elevated concentrations of hydrogen at both poles• It does not tell us the form of the hydrogen
    8. 8. The “Famous” LP maps Feldman, W.C. et al. Science 281, 1496-1500 (1998) Map courtesy of D. Lawrence, Los Alamos National Laboratory.(dark blue/purple <-> low # neutrons <-> high hydrogen <-> water?)
    9. 9. Evidence against ice lakes at poles Hi-Res Arecibo & Green Bank radar – 2005 Ref: Campbell, D.B. et al. Nature, 443, 835-837 (2006)• Higher spatial res. (20 m) than 1994 Clementine & 1992 Arecibo data (125 m)• Surveyed south pole and nearside to latitude ~65° S• Data indicate correlation between areas of high CPR with walls and ejecta deposits – Shackleton had same CPR values as Schomberger A&G, and many other young craters – High CPR areas in Shackleton are in both permanent shadow and seasonal illumination• Conclude high CPR in Shackleton is not due to ice deposits – But they conclude they are open to possibility very low abundance (1-2% Radar image Moon South Pole by mass) mixed in grains from the (left) OC 100m; (right) CPR 500 m Fig1 from Campbell, D.B. et al. Nature, 443, 835 (2006) upper 1 m of regolith
    10. 10. Evidence against ice lakes at poles; temperature is cold enough to support ice Selene (Kaguya) Terrain Camera – 2007 Ref: Haruyama, J. et al. Science, 322, 938-939 (2008)• Terrain Camera (10 m res.) surveyed inside Shackleton Crater – Targeted during lunar mid-summer to get max. illumination of the shadowed regions by sunlight scattered off nearby higher terrains – Discovered small craters on inner wall (100’s m dia.), mount-like features (300-400m thick), & central hill (200m height)• Derived temperature measurement of Shackleton floor ~88 K (max) – Cold enough to retain water-ice• Did not find bright areas in Shackleton that could be due to pure water-ice – Looking for albedo ~1.0• They also conclude they are open to possibility very low abundance (1-2% by mass) mixed in grains from the upper 1 m of regolith
    11. 11. How could there be water at the lunar poles?• The Sun never rises morethan a few degreesabove the polar horizon sothe crater floors are inpermanent shadow (PSR).• The crater floors are verycold with temperatures< -200° C (70K, -328° F), so Many orbits Clementine datawater molecules move very South Pole (Ben Bussey, APL)slowly and are trapped forbillions of years.(On October 9, 2009, LCROSS performed the first “in-situ” study of a PSR.)
    12. 12. Where could water ice come from?• Over the history of the Moon, when comets or • Water molecules at lower latitudes may formasteroids impact the Moons surface, they from interactions with hydrogen streaming outbriefly produce a very thin atmosphere that in the solar wind.quickly escapes into space. • These water molecules may get baked out of• Any water vapor that enters permanently the lunar soil and can then get trapped in polarshadowed craters could condense and craters.concentrate there. (volatiles from comets, asteroids, IDPs, solar wind, GMCs, the Moon itself!)
    13. 13. How much water could there be?• There is ~12,500 km2 of permanently shadowed terrain on the Moon.• If the top 1 meter of this area were to hold 1% water (by mass)*, that would be equivalent to about 4.1 x 1011 liters of water!• This is approximately 2% the volume of the Great Salt Lake in Utah. (*The Sahara desert is 1.2% water (by mass) in its top 20cm, with 2.5-4.5% at 3m.)
    14. 14. Enter LCROSS-The pathfinderLCROSS had a challenging set of constraints:• We had to fit within 1000Kg wet mass…• We had to design and build the payload, spacecraft and mission in only 30 months!• We had a cost-cap of $79M, including reserves…• We couldn’t levy any requirements on LRO…• As a NASA Class D mission some programmatic and technical simplifications could be leveraged
    15. 15. The LCROSS Experiment Flash Curtain Crater ~0.1 min 3.0 min 1 min• Impact the Moon at 2.5 km/sec (5,600 mph) with a ~2366 kg (5216 lb) Centaur upper stage and create an ejecta cloud into the sunlight for observation• Observe the impact and ejecta with instruments that can detect water• Four minutes later the ~625 kg (1378 lb) LCROSS S/C itself impacts at 2.5 km/s
    16. 16. Excavating with 6.5-7 billion Joules• About equal to 1.5 tons of TNT• Minimum of 200 tons lunar rock and soil expected to be excavated• New crater estimated to have ~20-25 m diameter and ~3m depth• Similar in size to East Crater at Apollo 11 landing site
    17. 17. Anatomy of an Impact – flash, curtain, crater ARC Vertical Gun Experiments Step 1 Step 5 Impact flash Nadir View of Impact and Ejecta Curtain Step 2 Step 6 Incandescent particles Crater rim Time Time Step 3 Step 7 “Sunrise” Reverse ejecta Ejecta Step 4 Step 8Curtain Into sunlight Scales to ~2 sec after Pete Schultz Centaur impact
    18. 18. Recent “Controlled” Lunar Impacts S/C Impact Date S/C Mass S/C Velocity Impact angle Impact Location Observations at impact from horizon. Hiten/ 10 Apr 1993 143 kg 2.33 km/s 42° 55°E, 32.4°S Flash Muses (hydrazine) LP 31 Jul 1999 161 kg 1.69 km/s 6.3° South pole area NullSMART-1 3 Sep 2006 285 kg 2 km/s 1° 46.2°W, 34.4° S Flash, plumeChange’1 1 Mar 2009 2350 kg ? ? just south of the ? lunar equator, at 52.36 degrees East LongitudeKaguya 10 Jun 2009 ~1800 kg 1.8 km/s 1° 80.4°E, 65.5°S Flash(Selene)LCROSS 09 Oct 2009 2366 kg 2.5 km/s >85 ° 48.703°W, 84.675°S; Flash, Plume, CraterLCROSS 09 Oct 2009 625 kg 2.5 km/s >85 ° 48.703°W, 84.675°S; Null (to date) S-S/C
    19. 19. Why LCROSS would be different…. 400 LCROSS SMART-1 LCROSS Centaur 350 LP 300 LCROSS S-S/C NOTE: LCROSS Predictions shown. LP/SMART-1 250 actuals shown 200 LCROSS S-S/C 150 100 SMART-1 (hill side impact) Ejecta Mass (Metric Tones) 50 0 0 LP 20 40 60 80 Impact Angle (degrees)SMART-1 (grazing impact)
    20. 20. ARC Vertical Gun Experiments
    21. 21. LCROSS was an artificial impactor (natural impacts* happen all the time)Ref: Montañés-Rodríguez, Pallé, & Goode, AJ, 134, 1145-1149 (2007)NASA Marshall Lunar Impact Monitoring Program (*Natural impacts typically have much more energy than LCROSS’s 6-7e9 Joules.)
    22. 22. The LCROSS Mission Recipe• Step 1: Hitch a ride to the Moon • (Thanks LRO)• Step 2: Part with LRO, but hang onto that rocket! • (we’ll use it later)• Step 3: Tug it around the Earth• Step 4: Point it toward our crater• Step 5: Let go!• Step 6: Slow-down & watch what kicks-up• Step 7: Send pics & data back to Earth• Step 8: Say good-bye • (Taste regolith!)
    23. 23. The LCROSS Mission Concept 1. Launched stacked with LRO 2. After Lunar swing-by, enter a 4 June 18, 2009 month cruise around Earth3. October 9, 4. S-S/C observes 2009, target the impact, ejecta Centaur Upper cloud and Stage and resulting crater, position S-S/C making to fly 4 minutes measurements behind until impacting itself
    24. 24. Spacecraft & Impactor
    25. 25. Secondary Payload Approach Atlas VLCROSS literallyhitched a ride to the moon! Delta II When LRO upgraded to a larger launch vehicle, there was an extra 1kg launch mass available.(LCROSS was required to meet a 28 month, ATP to launch, schedule, and to have minimal impact to LRO development and launch.)
    26. 26. Secondary Payload Approach
    27. 27. Secondary Payload Approach
    28. 28. “Creativity Loves Constraints” LCROSS’ Innovative Approach Re-use of upper-Centaur stage as the 2300kg impactor Turn the ESPA ring into the actual spacecraft mechanical structure Spare Tracking Data Relay System satellite propellant tank Petal-like panels fold up and down during I&T, eased access
    29. 29. “Creativity Loves Constraints” Leveraged TechnologyShares the same build-to-print Propulsion System uses all avionics suite as LRO commercially available parts Star Tracker & IRU & ACS FSW similar to LRO’s arrangement NG Flight Software Heritage, using 10 year old code, just updated
    30. 30. “Creativity Loves Constraints” COTS Payload
    31. 31. Kimberly Ennico & MarkShirley testing the LCROSSpayload at NASA ARC (left)and NGST (right)
    32. 32. Mission Day 0 (09-169; Jun 18) Launch! 5:32pm EDTMission Ops Center NASA Ames Launch from Cape Canaveral, FL Fairing Earth LCROSS star tracker Fairing separation
    33. 33. Where’s LCROSS?
    34. 34. LCROSS taken through Liverpool 2-meter Telescope, La Palma, Canary Islands – Robert Smith
    35. 35. LCROSS in flight taken through an amateur 16-inch telescope – Paul Mortfield
    36. 36. Where’s LCROSS?LCROSS in flight taken through an amateur 16-inch telescope – Paul Mortfield
    37. 37. Where’s LCROSS?
    38. 38. Where’s LCROSS?
    39. 39. Mission Day 4 (09-173; Jun 22) Starfield CalibrationAngular distance between αAquila (Altair) and γAquila (Tarazed) on the sky is 1.86 degrees and wasmeasured to be 46 pixels (along the diagonal) on NIR2. This confirmed a platescale of ~1.89/46 = 0.04degrees/pixel for NIR2 (at least within the central region of the array).
    40. 40. Mission Day 5 (09-174; Jun 23) Lunar Swingby Ennico, et al. (2009)
    41. 41. Mission Day 5 (09-174; Jun 23) Lunar Swingby (This was the scene of Lunar Swingby, June 23, ~2:30am.)Tony Colaprete (maroon shirt), reviews live data, Kim Ennico (black shirt) in front compares live data to expected performance using checklists. Jen Heldmann (in back) updates STK viewpoint for live streaming test.
    42. 42. Mission Day 44 (09-213; Aug 01) Earth Calibration at 360,000 km North NorthNIR1 MIR1*NIR2 MIR2 Full Earth at 360,000km O3 O2γ CO2 H2O H2O H2O CO2 CH4 O3 Ennico, et al. in prep.
    43. 43. Mission Day 60 (09-229; Aug 17) Earth Calibration at 520,000 kmCrescent Earth at 520,000km. Crescent Moon at 881,000 km.
    44. 44. Mission Day 92 (09-261; Sep 18) Earth Calibration at 560,000 km STK Boresight MapNIR1 (1.4-1.7um) NIR2 (0.9-1.7um) MIR1 (6.0-10um) MIR2 (6.0-13.5um) Quarter-Earth at 560,000 km Ennico, et al. in prep.
    45. 45. Mission Day 113 (09-282; Oct 09) SeparationMIR_S1_W0000_T3425736m453 MIR_S1_W0000_T3425953m305d = 150 m d = 300 mCam6_W0000_T3425736m969 MIR_S1_W0000_T3426668m025d = 150 m d = 800 m Ennico, et al. (2009)
    46. 46. Mission Day 113 (09-282; Oct 09) SeparationCentaur Light curves observed from Earth 3-5 hrs before impact Buie & Ryan, SWRI & Magdalena Ridge
    47. 47. Mission Day 113 (09-282; Oct 09) Impact! (This was the scene of Impact at the Science Ops Center, Oct 9, ~4:30am.)Tony Colaprete (black shirt), reviews live data, Kim Ennico (maroon shirt) on voice command to MOS to command camera change request based on live data analysis by Tony & Kim (on the fly).
    48. 48. Where did we go and why? Target Selection Criteria: 1. Ejecta Illumination 2. Association with hydrogen • 3. Observable to Earth 4. “Smooth”, flat terrain LCROSS Visible Camera Image 2009-09-09 11:00 UTC Cabeus CraterFinal decision considered available data, status of LCROSSpayload, ability of LRO to observe, and limits of Earth observingfor each site.
    49. 49. Where did we go? X Goldstone map
    50. 50. Where did we go? X Goldstone map
    51. 51. Where did we go? Cabeus A: • Best Earth observing (not perfect since backdrop would have been lit moon) • Hydrogen association was questionableCabeus B:• No obviousassociationwith hydrogen Cabeus: Obvious hydrogen, but worst Earth observing LCROSS Visible Camera Image 2009-09-09 11:30 UTC (Viewpoint from LCROSS, Oct 9)
    52. 52. Where did we go? Target Crater CabeusTarget Crater Cabeus Nancy Chanover, APO (Viewpoint from Earth, Oct 9)
    53. 53. Where did we go? Expected Plume Area Nancy Chanover, APO (Viewpoint from Earth, Oct 9)
    54. 54. Where did we go?(Target area with good elevation angles to Sun for ejecta illumination. Source: LRO LOLA.)
    55. 55. How Close Did We Hit? Marshall, W., Shirley, M. et al. in prep.(We hit within 100 meters of our predicted target!)
    56. 56. So... Why no big plume? Schultz, et al (2010) Predicted What we think we did
    57. 57. What did we see? Cam1_W0000_T3460421m473 Schultz, et al (2010)(Observed expanded ejecta cloud 10-12km in diameter at 20s after impact. Visible camera imaged curtain at t+8s through t+42s, before cloud dropped below sensitivity range).
    58. 58. What did we see? Multi-pixel signature >1km structure t+0s t+2s t+4sMIR_S1_W0000_T3460402m651.png MIR_S1_W0000_T3460404m653.png MIR_S1_W0000_T3460406m655.pngt+6s t+8s t+10sMIR_S1_W0000_T3460408m657.png MIR_S1_W0000_T3460410m659.png MIR_S1_W0000_T3460412m159.png(Thermal signature seen in mid-IR cameras t+2-10s believed to be impact-heated ballistic ejecta that did not get into sunlight (low-angle plume). Ejecta after 4s is within a single pixel, ~1km/pix at this altitude.)
    59. 59. Coordinating ObservationsView of Moon from Earth on 9 October 2009, 4:30 a.m. PDT
    60. 60. Coordinating ObservationsA Coordinated Professional Observation Campaign using Earth, Earth-Orbit and LRO has been part of the mission from the start.
    61. 61. Coordinating ObservationsBackyard astronomer observations are coordinated through the LCROSS Google Group
    62. 62. Other EyesCanada France Hawaii Telescope (Hawaii)Apache Point Observatory (New Mexico)Infrared Telescope Facility (IRTF, Hawaii)MMT Observatory (Arizona)Magdalena Ridge Observatory (New Mexico)Keck (Hawaii)Gemini North (Hawaii)Subaru Telescope (Hawaii)Korea Astronomy & Space Science Institute (Arizona & Korea)Mount Wilson (California)Air Force AEOS Telescope (Hawaii)Allen Telescope Array (California)Palomar Observatory (California)Lick Observatory (California)Hubble Space Telescope, Lunar Reconnaissance OrbiterOdin, IKONOS, GeoEye-1 LCROS EBOC Campaign
    63. 63. Coordinating Observations NASA GSFC
    64. 64. Coordinating Observations
    65. 65. Coordinating ObservationsApache Point Observatory (New Mexico) Nancy Chanover, APO
    66. 66. Coordinating ObservationsKeck guider image (Mauna Kea, Hawaii) Wooden, et al.
    67. 67. Coordinating ObservationsCanada France Hawaii Telescope Christian Veillet, CFHT
    68. 68. Coordinating ObservationsMMT Observatory, Arizona BEFORE AFTER Faith Vilas, MMT
    69. 69. LCROSS Water Measurement
    70. 70. New Lunar Water Evidence (?)- 2009 Must excavate 1 ton regolith to get 32oz (0.25 gal) ‘water.’ (1000 ppm) Chandrayaan-1 Deep Impact CassiniData from these probes has shown that small amounts of waterare widespread across the upper millimeter surface of the Moon. Theamount of water may change during the course of the lunar day. Clark, et al (2009), Pieters, et al (2009), Sunshine, et al (2009)
    71. 71. LCROSS’ (different) water measurement The measurement...
    72. 72. LCROSS’ (different) water measurement Model a 230°C (500K) greybody...
    73. 73. LCROSS’ (different) water measurement H2O H2O H2O Add to it a water model...
    74. 74. LCROSS’ (different) water measurement H2O H2O Other Other H2O Add in some other simple molecules...
    75. 75. So... How Much water?• LCROSS (Colaprete, et al 2010) – sampled one area, created a 20-30m diameter crater, excavated ~250 metric tons (from model) – only observed 2202-4382 kg sunlit material (above 833m alt) at impact+8s. – two band depths measured • H2O (1.4 & 1.8um) -> 145 kg H2O vapor+ice • OH (308-310nm) -> 110 kg H2O vapor+ice – model dependent (mixing) -> mean water concentration 7.4 wt% ± 5.4 wt% – observed 688-1369 kg sunlit material at impact +30-200s• LAMP/LRO (Hurley, et al. 2009) – observed H2, peak column density ~158kg H2 released, – fit models -> <400 kg H2O released, – assumed 20,000kg was released -> <2% wt%• LEND/LRO (Mitrofanov, et al. 2010) – 2100-5400 ppm measurements -> 1.9-4.9 wt%• Diviner/LRO (Hayne, et al. 2010) – observed 760-1800 kg sunlit material at impact +90s M3 “0.25 gal H2O/1 ton soil”; LCROSS “10 gal H2O/1 ton soil”
    76. 76. In Summary (1 of 3)• LCROSS proved that a new class of mission (NASA Class D) high science payoff at low cost/high risk is possible• Tight schedule & budget constraints (or you would lose your ride) forced proactive and rigorous project management with very visible risk management• Lifecycle of “cradle to grave” in <3 years excellent training experience• Design engineers used as part of ops team was essential in quick turn-around response to anomalies and events• Ruggedized-COTS instruments did perform well in space (~5-10 hrs operation time), high performance at low cost• Never underestimate the importance of on-orbit calibration data (saved our bacon)
    77. 77. In Summary (2 of 3)• Impact appears to have occurred in a volatile rich area: • Water …and other stuff!! (e.g., CH4, CO2, SO2, NH3, Na, K, CO, NH2) possibly observed…work occurring now to get unique identification• Band depths and OH emission strengths indicate significant amounts of water (>150 kg vapor and ice) – Reported concentration: 7.4 wt% ± 5.4 wt% (Colaprete, et al. 2010) – From LEND: ~ 1.9 - 4.9 wt% (for 3 cm dry layer) (Mitrofanov, et al. 2010) – Remember, ESMD requirement for moon base was 1 wt%• The amount and types of volatiles suggest: – The very cold temperatures sequester all sorts of volatiles (see Zhang & Paige, 2009) – Need multiple source model (see Lucey, 2000)
    78. 78. In Summary (3 of 3) Science can be surprising!Updates on the LCROSS mission results are posted at Prediction What may have happened...
    79. 79. LCROSS Papers/PresentationsLunar Exploration Analysis Group (LEAG), November 17-19, 2009, Houston, TX (Impact +1 m) Colaprete et al., Schultz et al., Heldmann et al., Wooden et al.,American Geophysical Union (AGU), December 12-16, 2009, San Francisco, CA (Impact +2 m) Colaprete et al., Schultz et al., Chin et al., McClanahan et al., Hermalyn et al., Ennico et al., Heldmann et al., Wooden et al., Hurley et al.,Submitted to Science, Jan 2010 (Impact + 3m) Colaprete et al., Schultz et al., Hayne, et al. Goldstone et al. Mitrofanov, et al.Lunar and Planetary Science Conference, March 1-5, 2010, Houston , TX (Impact +5 m) Seven (7) oral and eleven (11) poster presentations in Special Session: “A New Moon: LCROSS, Chandrayaan ChangE-1 Results”