Planetary Defense: Near Earth Objects (NEOS) S. Pete Worden Director, NASA Ames Research Center Moffett Field, CA USA 23 Oct, 2008 Definitions • NEOs - Near Earth Objects – Comets and asteroids that approach the sun to within 1.3 AU • PHOs - Potentially Hazardous Objects – NEOs with orbits within 0.05 AU of the Earth’s orbit (~20 lunar distances) and that could cause substantial damage to the Earth • Detection and Tracking – Discovery of NEOs and 2 distinct observations within 1 week • Cataloguing – Full orbit determination, publishing the orbit, archiving the data • Warning – Risk analysis including alerts, impact probability, and impact energy • Characterizing an Object – Determining size, shape, rotation, etc. to inform mitigation options • Deflection – Action to divert a PHO on a likely collision course with the Earth Overarching Questions Where are the PHOs? (90% 140m by end of 2020) Search systems Which are Threats? (precision orbit and mass / size) Search systems What are the Characteristics of a Potential Threat that would be Necessary to Mitigate It? Survey Remote sensors In-situ visits to threats Deflection With that Information, What can We do About the Threat? Frequency of NEOs by Size (or Magnitude) Survey Parameters Constant Power Law (102) • ~21% of NEOs are potentially Conservative Fit to Data hazardous • Survey to find ~18,000 PHOs ~100k NEOs > 140m 140 m and larger ~1k NEOs > 1km • Will find many other minor planets and smaller threats • Data system must be sized for 2 million observations of up to 500,000 objects • Discovery of ~15 PHOs per day will generate a peak of 2-3 warnings per week Discovery rate will require a much more robust data analysis infrastructure Known (current) NEO Population The Inner Solar System in 2006 Known • 340,000 2006 minor planets • ~4500 NEOs Earth • ~850 PHOs Crossing (NEO) New NEO Survey Will Likely Find Outside • 100,000+ NEOs Earth’s (> 140m) • 20,000+ PHOs Orbit Picture from: Scott Manley. Armagh Observatory Frequency Diameter Energy Brightness (m) (kton) (Mv) Once per hour 0.15 2e-4 -14 Once per day 0.4 6e-3 -17 Once per week 0.9 5e-2 -19 Once per month 1.5 0.27 -20 Once per year 4 4.3 -22 Once per 9 55 -24 decade Once per 21 700 -26 century Once per 50 9200 -28 millenia Direction from 2005 NASA Appropriation Bill • [Established that] NASA be directed to detecting, tracking, cataloguing, and characterizing [DTCC] near-Earth asteroids and comets in order to provide warning and mitigation of the hazard of such Near Earth Objects (NEOs). • The NASA Administrator shall plan, develop, and implement a NEO Survey program to DTCC the physical characteristics of near-Earth objects equal to or greater than 140 meters 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% completion of its NEO catalogue (based on statistically predicted populations of near-Earth objects) within 15 years after the date of enactment of this Act (2020). • [Deliver] an analysis of possible alternatives that NASA may employ to carry out the Survey program, including ground-based and space-based alternatives with technical descriptions. • [Deliver] a recommended option and proposed budget to carry out the Survey program pursuant to the recommended option. • [Deliver] an analysis of possible alternatives that NASA could employ to divert an object on a likely collision course with Earth. NASA Administrator Response to Congress - 2007 • “At present, NASA cannot commit to the initiation of an expanded NEO Survey program beyond the Spaceguard program without further analysis and program planning. NASA cannot initiate such a program at this time due to current budget constraints. The exemplar NEO Survey Program described in the attached report is illustrative only and does not represent a new funding request or a commitment on the part of NASA to carry out such a program. While the mission of NEO detection, tracking, and characterization is important, the legislated goal of a new survey program may still be achieved within 15 years.” Notional NEO Program • Find Suitable small NEOs • Mount Nanosat Mission(s) for Reconnaissance • SMEX Class Mission(s) to Selected NEO _ followed by DISCOVERY Class Sample Returns • “Apollo 8” Mission – no “lander” • “Apollo 10” with lander • Consider Deflection Options Detection Performance • 1-2% uncertainty in relative performance • Up to 5% in absolute performance, Buildup Example 1-2% for best performing concepts 100% 90% GOAL 80% 70% 60% Existing Assets (in all options) 50% Shared LSST Dedicated LSST 40% Shared PS4 + Shared LSST (Baseline) 30% Baseline + Dedicated LSST Baseline + 0.5m IR @ L1 20% Baseline + 0.5m IR in Venus-like Orbit 10% Percent D>140m PHO Population Catalogued Percent D>140m PHO Population 0% 2008 2012 2016 2020 2024 2028 Calendar Year Detection and Tracking Individual Element Life Cycle Costs thru 2020 Element Life Cycle Cost through 2020 ($B FY06) $0.0 $0.5 $1.0 $1.5 $2.0 Shared PS4 * NASA Cost of Shared Systems (shared w/NSF and DoE) Dedicated PS4 $0.0 * • NASA replaces private development funding, if any Dedicated PS 8 $0.09 • For PS4, NASA pays 30% of estimated ops costs • For LSST, NASA pays 50% of estimated ops costs Dedicated PS 16 $0.19 Shared LSST $0.14 Reliance on Shared Dedicated LSST $0.51 Systems Carries Cost and Schedule Risk 0.5m IR @ L1 $0.80 1.0m IR @ L1 $1.0 0.5m IR Venus-Like Orbit $0.82 1.0m IR Venus-Like Orbit $1.1 1.0m Vis Venus-Like Orbit $1.5 2.0m Vis Venus-Like Orbit $1.8 * Costs under $50M Cost to 70% Confidence No cataloguing included University of Hawaii Pan-STARRS Engineering drawing of the 1.8-meter diameter PS1 telescope inside its building on Haleakala. Common Spacecraft Bus – Modular Approach Bus Module Multi-Mission Capability enabled by Modular Bus Design – Select Modules to meet Mission Requirements Orbiter Payload Module Requirements Small Lander Launch Vehicle: - Falcon-1e or Minotaur V Extension Environment: Module - Multiple Lunar Orbits Featherweight - Equatorial or Polar Landings Lander Mission duration: - Orbiter - 1 Year in Lunar Orbit Design Configurations: 150Kg+ Orbiter on a Minotaur V Propulsion - Lander - 1 Lunar Day - 50 Kg science payload Module 130 Kg Lander (four tanks) on a Minotaur V - 40 Kg surface science payload, 200 Watts 103 Kg Lander (four tanks) on a Minotaur V - 15 Kg surface science payload, 100 Watts 55Kg Lander (two tanks) on a Falcon 1e - 1 Kg surface payload Legs Development Approach: Short Schedule, Incremental Development, Aggressive Testing Heavily leverages15 DoD investments in Propulsion, Avionics, and Flight Software Lunar Atmosphere & Dust Environment Explorer (LADEE) Objective – Measure Lunar Dust ----Supports ESMD – Examine the Lunar atmosphere • NRC recommendation to study the atmosphere early while still in low mass & pristine state Key parameters • Launch in 2010 (goal) or 2011 (threshold) • Mission length 100 days Spacecraft – Type: Small Orbiter - Category III, Class D – Provider: ARC provided small sat (partnered with GSFC) – $80M LCC with reserve (excluding LV) – Phase A: Apr. 1 to Oct. 1, 2008 Instruments – Core Instruments: Dust Counter, Mass Spectrometer, – Science Definition Team (SDT) to provide Science priorities for optional 3rd instrument • SDT activity Feb. 15 to Apr 15 (Final report due May 15, 2008) – RFI to be used to identify in-house NASA instruments available • Goal :Leverage use of clones or spares of existing instruments • Backup Option: Compete selection using SALMON 2008 AO process Launch Vehicle – Launch with GRAIL on Delta II Cis-Lunar Mission Concepts = High Thrust (ΔV m/sec) LOI-WSB (700) = Low Thrust WSB Optimization using LT Arc = Trajectory Correction (HT/LT) Altitude Control Lunar GEO GTO Libration PMF Orbit Insertion/ TTI Earth AMF Point (1,100) (700) (1,900) Station Keeping Altitude Control Repositioning/ LOI-Direct Station Keeping (800) TTI = Transfer Trajectory Insertion AMF = Apogee Motor Fire PMF = Perigee Motor Fire LOI = Lunar Orbit Insertion WSB = Weak Stability Boundary Asteroid Itokawa, ISS, and CEV Orion CEV Orion ~17 m (cross section) 540 meters ~100 meters (ISS at 12A.1 Stage) JAXA, NASA NEO Mission Launch Concepts EELV ARES I US ARES IV Used to used to loft unmanned loft Orion Centaur Upper ARES I Stage Used to loft Orion and LOWER Crew ARES V Core BOOKEND + Boosters MID-VOLUME IV (DUAL LAUNCH) (SINGLE LAUNCH) ARES V ARES V ARES I used to Used to Used to loft Orion loft EDS loft Orion + LSAM MID-VOLUME V UPPER BOOKEND (SINGLE LAUNCH) (DUAL LAUNCH) Vehicles are not to scale. Orion Mods & Delta V for 90-day NEO Mission Orion Modifications lb Crew Module (CM) Radiation Shielding RP -434 Removed, replaced by extra water Crew Module (CM) ECLSS 245 Added moisture recuperator, CHX hardware, and IX/UV hardware Crew Module (CM) Crew Systems -50 Removed seats.etc. Crew Module (CM) Crew Systems (GFE) 149 Increase food & trash storage, removed 2 suits, etc. Crew Module GFE (CM) Personnel (GFE) -390 Reduced crew from 4 to 2 Crew Module (CM) ECLSS Consumables 84 Increased crew-days Service Module (SM) ECLSS Consumables 983 Increased crew-days TOTAL 587 No change to: Telecom - OK to 6 Mkm Power - never far from 1 AU Docking - assumed LIDS, potential for reduction From TeamX study in December Orion Mass klb Baseline Dry Mass 24.7 Modified Dry Mass at Launch 25.3 Dry Mass at Separation 24.4 Propellant Mass at Launch 20.5 Circ. & EOR 2.6 Residual 0.5 Usable - Post EOR 17.4 Usable - Single Launch 20.0 Isp 323 sec Delta V Capability Post-EOR 1.68 km/sec Delta V Capability Single Launch 1.87 km/sec NEO Orion Configuration Overview NEO Science Payload Bay (same as the Proposed Lunar Science Bay) The Orion’s ∂V capability post-LEO docking is 1.68 km/sec.