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Opportunities for Near Earth Object Exploration Future In-Space Operations Colloquium

Opportunities for Near Earth Object Exploration Future In-Space Operations Colloquium. Lindley Johnson Program Executive NASA HQ 29 Sep 2010. Terminology. “Near Earth Objects (NEOs)”- any small body (comet or asteroid) passing within 1.3 Astronomical Unit (AU) of the Sun

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Opportunities for Near Earth Object Exploration Future In-Space Operations Colloquium

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  1. Opportunities for Near Earth ObjectExplorationFuture In-Space Operations Colloquium Lindley Johnson Program Executive NASA HQ 29 Sep 2010

  2. Terminology • “Near Earth Objects (NEOs)”- any small body (comet or asteroid) passing within 1.3 Astronomical Unit (AU) of the Sun • 1 AU is the distance from Earth to Sun = ~ 150 million kilometers (km) • NEOs are predicted to pass within ~ 45 million km of Earth’s orbit • Population of: • Near Earth Asteroids (NEAs) • Near Earth Comets (NECs) – also called Earth Approaching Comets (EACs) • 85 currently known • “Potentially Hazardous Objects (PHOs)” – small body that has potential risk of impacting the Earth at some point in the future • NEOs passing within 0.05 AU of Earth’s orbit • ~ 8 million km = 20 times the distance to the Moon • Appears to be about 20% of all NEOs discovered • Human mission accessible objects are a subset of PHOs

  3. Earth’s Cratered Past

  4. Our “Big Buddy” Jupiter Our “Big Brother “ Jupiter continually takes hits from relatively large objects, including two sighted this summer. The impact of comet Shoemaker-Levy 9 in July 1994 brought both astronomical and media attention to the impact threat

  5. U.S. early warning satellites detected a flash that indicated an energy release comparable to the Hiroshima burst. We see about 30 such bursts per year, but this one was one of the largest we have ever seen. The event was caused by the impact of a small asteroid, probably about 5-10 meters in diameter, on the earth's atmosphere. --Statement of Brigadier General Simon P. Worden, Deputy Director for Operations, United States Strategic Command before the House Science Committee Space and Aeronautics Subcommittee on Near-Earth Object Threat October 3, 2002 “The Hard Rain” Fireball Data Points 2003 - 2005

  6. Impact Frequencies and Consequences

  7. Effects of TUNGUSKA EVENT June 1908 – 100 years ago

  8. NEO Observation Program US component to International Spaceguard Survey effort Has provided 98% of new detections of NEOs Began with NASA commitment to House Committee on Science in May, 1998 • Averaged ~$4M/year R&A funding since 2002 Scientific Objective: Discover 90% of NEOs larger than 1 kilometer in size within 10 years (1998 – 2008) NASA Authorization Act of 2005 provided additional direction (but no additional funding) “…plan, develop, and implement a Near-Earth Object Survey program to detect, track, catalogue, and characterize the physical characteristics of near-Earth objects equal to or greater than 140meters in diameter in order to assess the threat of such near-Earth objects to the Earth. It shall be the goal of the Survey program to achieve 90 percent completion of its near-Earth object catalogue within 15 years [by 2020].

  9. Catalina Sky Survey UofAZ Arizona & Australia LINEAR MIT/LL Soccoro, NM NASA’s NEO Search Program(Current Systems) NEO-WISE JPL Sun-synch LEO • Minor Planet Center (MPC) • IAU sanctioned • Int’l observation database • Initial orbit determination • www.cfa.harvard.edu/iau/mpc.html • NEO Program Office @ JPL • Program coordination • Precision orbit determination • Automated SENTRY • www.neo.jpl.nasa.gov Pan-STARRS Uof HI Haleakula, Maui

  10. Discovery MetricsDiscovery Rate of >1km NEOs

  11. Discovery Metrics } Estimated Population 940 - 1050 Goal 850 - 940 Achieved minimum goal 903* (85-95%) as of 9/27/10 *Includes 85 NECs 6393 smaller objects also found

  12. Known Near Earth Asteriod Population Start of NASA NEO Program

  13. Population of NEAs by Size, Brightness, Impact Energy & Frequency (Harris 2006) 300,000 50 m Numbers (powers of 10) 20,000 140 m 1,000 1 km 0.01 0.1 1 10

  14. Known Near Earth Asteroid Population ~40% ~8% < 1% 85% << 1%

  15. Recent Close Approaches Two Small Asteroids Pass Close by Earth on September 8, 2010

  16. Missions to NEOsOpportunities and Constraints

  17. Encounters to Date

  18. Near Earth Asteroid Rendezvous (NEAR) • First Discovery-class mission • Launched February 1996 • Flyby Mathilde June 1997 • Accidental Flyby Eros December 1998 • Started Eros orbit February 2000 • End of Mission February 2001 • Touch down on Eros!

  19. Deep Impact • Discovery 8 mission • Launched January 2005 • Probe impacts Tempel 1 July 4th, 2005 • Main spacecraft flies by • Begins EPOXI mission in 2007

  20. Hayabusa (Muses-C) • Japanese space agency mission • Launched May 2003 • Arrived Itokawa September 2005 • Sample collection attempt Nov 2005 • Started return April 2007 • Sample Capsule returned June 2010

  21. Comparing Asteroids (and Comet Nuclei)

  22. Comparing Asteroids Itokawa

  23. The Future Encounters

  24. Exploration Precursor Robotic Missions (xPRM) 24 • xPRM to be uniquely poised to provide critical Strategic Knowledge for Exploration for diverse set of destinations. • xPRM starting in this decade would enable Human Exploration in the next. • Analogous to robotic Surveyor landers ahead of Apollo human missions • Proposed scope uniquely focuses on HSF objectives while leveraging unique capabilities of partners. • No other program would fulfill this objective. • Fully consistent with current best estimate objectives for future HSF at NASA NOTIONAL Point of Departure – Subject to Change

  25. Why Missions to NEOs? • Planetary Science • Material represents the most primitive building blocks of Solar System • Human Space Exploration • Early destinations for push out into Solar System • Unique Resources • For exploration of space and return to Earth • Planetary Defense • To design and test methods to deflect impactors

  26. HSF NEO Mission Constraints Preliminary outline of possible constraints for human mission success and safety: • Accessible with projected capability = < 7.5 (?) km/sec dV • Mission less than 180 (?) days round trip • Return entry velocity less than 12 km/sec • Greater than 50 meter sized object • Object in simple axis, slow rotation • Accessible by robotic precursor mission at least 3 years prior to crew launch

  27. NEO Human-spaceflight Accessible Targets Study(NHATS) Preliminary Results

  28. NEO Human spaceflight Accessible Targets Study(NHATS) Preliminary Results

  29. Population of NEAs by Size, Brightness, Impact Energy & Frequency (Harris 2006) 300,000 50 m Numbers (powers of 10) 20,000 140 m 1,000 1 km Need to find objects in this population 0.1 0.5 1

  30. Population estimates *Based on NEO population studies of Bill Bottke, et al

  31. “NEOStar” Concept X Spitzer Kepler ≈ “NEOStar”

  32. Bottomline: • For finding Human Exploration targets, a telescope in a Venus-like orbit is the most technically viable option ~400 potential targets from 2 years of observing • For Planetary Defense (detection & tracking of all PHOs), an IR telescope in a Venus-like orbit speeds up the search by a decade

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