Presentation to the Nuclear SystemsStrategic Roadmap Committee

5 April 2005

The B612 Mission Concept:A Candidate For Prometheus 1

Russell L. Schweickart, ChairmanB612 Foundation

www.B612Foundation.org

Introduction

• Presentation of the B612 concept as a candidate for the Prometheus 1 mission

• Background– B612 Foundation – Near-Earth object (NEO) environment

• Assumption– Presentation will be summary in nature with

details of interest left to Q&A at end– Related technical and professional papers are

available for those interested

B612 Foundation Basics

• What we are -– 501(c)3 non-profit corporation formed 9/7/02

• Who we are -– A group of astronomers, astronauts and

engineers involved in or with NEO issues

• Why we formed -– Concerned with coming high NEO discovery

rate but no organized work on deflection

• Our adopted goal -– “to deflect an asteroid, in a controlled manner,

by 2015”

B612 Founders

William Bottke; Southwest Research InstituteDennis Byrnes; NASA/Jet Propulsion LaboratoryFranklin Chang-Diaz; NASA/Johnson Space CenterClark Chapman; Southwest Research InstituteTony Dobrovolskis; NASA/Ames Research CenterDan Durda; Southwest Research InstituteJohn Grunsfeld; NASA/Johnson Space CenterMike Houts; NASA/Marshall Space Flight CenterPiet Hut; Institute for Advanced StudiesDon Korycansky; UC Santa CruzStanley Love; NASA/Johnson Space CenterEd Lu; NASA/Johnson Space Center

B612 Founders

Andrew Petro; NASA/Johnson Space Center

Dan Mazanek; NASA/Ames Research CenterBill Merline; Southwest Research InstituteDavid Morrison; NASA/Ames Research CenterSteve Ostro; NASA/Jet Propulsion LaboratoryDavid Poston; Los Alamos National LaboratoryDan Scheeres; University of MichiganRusty Schweickart; IndependentJared Squire; NASA/Johnson Space CenterBobby Williams; NASA/Jet Propulsion Laboratory

The NEO Environment

Spaceguard SurveyNASA’s goal: “Discover 90% of the NEO population (1 kilometer in diameter or larger) within 10 years (i.e., 2008)”

NASA NEO Science Definition Team“...recommends that the search ... produce a catalog that is 90% complete forpotentially hazardous objects (PHOs) larger than 140 meters.”

The NEO Environment

Current Potential Impacts

• Actual data: updated daily; catalogs all NEAs with non-zero probability of Earth impact in next 100 years.

• List will likely expand to hundreds of objects within the next 10 years as the search focuses on smaller dangerous objects (>100MT)

An Interesting Case

The 2004MN4Situation as of 23 Dec 04

Situation on 23 Dec 04

Situation on 28 Dec 04

Vrel=5.86 km/sec

Vrel=5.86 km/sec

deltaV=2.83 km/sec28 deg

2004MN4 close pass geometry

Encounter, 13 April 2029 @ 21:44:35 GMT

This NEA will be a magnitude 3 naked eye

object in the early evening sky in Northern

Europe

It will pass by Earth slightly inside the

geostationary orbit

GeostationaryOrbit

Sun

Nominal path and error ellipse of

2004 MN4 on 4/13/29 relative to Earth

(as of 4/1/05)

2029 Close Encounter

V Required to Deflect

An Interesting Case

2029 close approach

Note: Preliminary resultsonly. Shown by special permission of Andrea Carusi, University of Pisa.

Mission Concepts

• A1 - Actual deflection of incoming NEO– Conceptual only; to determine feasibility and establish

design requirements

• D2 - Full demonstration– Full demonstration of capability; dress rehearsal

• D1 - Basic demonstration– Initial capability demonstration and gathering of critical

engineering design information (Note: engineering design data could be gotten more timely and cheaply via early conventional mission)

• Rationale: top to bottom• Mission sequence: bottom to top

A1 – Actual Deflection

• Assumptions– ~200 meter diameter– rubble pile– principal axis rotator– getting there and basic pre-docking

surveillance for asteroid characterization and docking site are assumed

• Docking (not landing)– gast ~ 2.6 x 10-6 gearth (s/c weight <0.1 lbs)

– dock at pole– probably requires 3 axis control

A1 – Rotation Considerations

• For efficient use of fuel and time thrust must be applied parallel to the asteroid’s velocity vector (Vast)

• Since asteroids rotate with periods of 2 to 10 hours (200 meter diameter & above) this must be accounted for in the mission design

• Rejected concepts– Pulse thrust only when near parallel with Vast

– Dock at equator; despin asteroid, orient asteroid to align thrust parallel Vast and thrust to obtain required V

A1 – Rotation Considerations

• Since the structural balance of the asteroid is tied to its rotation reducing it to zero would likely cause fundamental restructuring, i.e. an asteroid quake.

• Survival of the s/c in this event is problematic.

De-spin then thrust

A1 – Rotation Considerations

Re-align spin then thrust

• There is always a depression angle where the resultant torque during thrusting maintains H directly below V

• Once aligned all fuel goes into achieving the desired V

A1 – Off Axis Thrusting

• Thrusting other than through the asteroid center of mass will require lateral support and a gimbaled engine.

• Additional knowledge of asteroidal surface structural characteristics is required for design.

Lateral support

D1 – Basic Demonstration

• Dock at pole and push asteroid to achieve a pre-planned V of 0.2 – 1.0 cm/sec in inertial direction

• Deploy scientific package to obtain critical data on surface structure

• Conduct additional scientific research

• Collect and return surface sample to Earth (optional)

D2 – Full Demonstration

• Build on D1 mission by deploying lateral support mechanism

• Complete full deflection mission objectives– Determine via onboard remote sensing

capability the required spin axis orientation for acceleration program

– Torque asteroid spin axis to pre-derived orientation

– Thrust parallel to asteroid velocity vector to achieve predetermined V

Candidate Asteroid Selection

• Since B612 is a demonstration mission, the target asteroid should be representative of an actual deflection but also “convenient”– Low V to rendezvous– No threat to Earth before or after mission– Preferably a rubble pile (worst case challenge)– Slow principal axis rotator to minimize fuel

required while validating attitude control technique

• B612 Foundation selected candidate asteroid 2000EH26 and JPL ran initial evaluation

Candidate Asteroid Selection

• JPL subsequently ran evaluations on more favorable asteroid candidates and selected 2004KE1 as most favorable in current catalog

• Following pages show JPL analytical results for initial 2000EH26 evaluation and notation for re-analysis using 2004KE1 as target asteroid

• Asteroid comparison (selected parameters)Designation a e i H G Ref----------- ---------- ---------- --------- ----- ---- ------2004 KE1 1.2993152 0.18115408 2.88147 21.95 0.15 JPL 62000 EH26 1.8528199 0.47718265 0.39343 21.27 0.15 JPL 35

• Target asteroid: 2000 EH26– Mass = 1.0 x 1010 kg

• Total V imparted to asteroid: 1.0 cm/s or 0.2 cm/s (along spin axis)• Launch date: 2011-2013• Two scenarios for starting conditions

– Launch to 1000 km orbit with spiral out to Earth escape– Launch to Earth escape (C3 = 0 km2/s2)

• Launch vehicle: Delta 4050H (i.e., Delta 4 Heavy)– Capability to 1000 km orbit: ~21,000 kg– Capability to C3 = 0 km2/s2: ~9,000 kg

• Three initial spacecraft acceleration levels: 0.12, 0.15, and 0.18 mm/s2 • Spacecraft dry mass: 18,000 kg• Electric propulsion system characteristics:

– Power to electric propulsion system is calculated to achieve specified initial spacecraft acceleration level

– Efficiency = 70%– Isp = 7000 s

Analytic Assumptions

2004 KE1

Analytic Process

• Spacecraft dry mass is fixed• Total V imparted to asteroid is fixed at 1.0 or 0.2 cm/s• Earth spiral out, interplanetary transfer and rendezvous Vs

are determined from optimized low-thrust trajectories assuming three different levels of initial spacecraft acceleration

• Power level available to electric propulsion system is calculated to achieve specified initial spacecraft acceleration level

• Initial spacecraft mass is calculated from specified dry mass and mission propellant requirements for the following:– Earth spiral out V (if applicable)– Interplanetary transfer V– Rendezvous V– Navigation V (fixed 200 m/s allocation)– Total V imparted to asteroid

• Calculate launch vehicle margin from initial spacecraft mass and launch vehicle capability

Initial Spacecraft Acceleration 0.12 mm/s^2 0.15 mm/s^2 0.18 mm/s^2 0.12 mm/s^2 0.15 mm/s^2 0.18 mm/s^2

Starting Condition 1000 km LEO 1000 km LEO 1000 km LEO C3 = 0 km2/s2 C3 = 0 km2/s2 C3 = 0 km2/s2

Date:Departure 7/11/11 11/28/11 2/28/12C3 = 0 km2/s2 3/1/13 3/17/13 3/28/13Asteroid Rendezvous 2/10/18 2/24/18 2/15/18 3/18/18 3/1/18 2/19/18EOM 3/19/19 1/14/19 11/12/18 6/2/19 2/19/19 12/13/18

Time Duration:Spiral Out to C 3 = 0 km2/s2 1.64 yrs 1.30 yrs 1.08 yrs N/A N/A N/AInterplanetary Transfer 4.95 yrs 4.94 yrs 4.89 yrs 5.07 yrs 4.97 yrs 4.91 yrsAsteroid Deflection 1.10 yrs 0.89 yrs 0.74 yrs 1.21 yrs 0.97 yrs 0.81 yrsTotal Mission Duration 7.69 yrs 7.13 yrs 6.71 yrs 6.28 yrs 5.94 yrs 5.73 yrs

V Requirements:Spiral Out 6.507 km/s 6.459 km/s 6.418 km/s N/A N/A N/AInterplanetary Transfer & Rendezvous 7.564 km/s 7.198 km/s 7.006 km/s 7.784 km/s 7.331 km/s 7.095 km/sStatistical Navigation 0.200 km/s 0.200 km/s 0.200 km/s 0.200 km/s 0.200 km/s 0.200 km/s

Propellant Requirements:Spiral Out 2,166 kg 2,138 kg 2,118 kg N/A N/A N/AInterplanetary Transfer 2,273 kg 2,157 kg 2,097 kg 2,343 kg 2,199 kg 2,125 kgStatistical Navigation 57 kg 57 kg 57 kg 57 kg 57 kg 57 kgAsteroid Deflection 1,457 kg 1,457 kg 1,457 kg 1,457 kg 1,457 kg 1,457 kgTotal Propellant 5,953 kg 5,809 kg 5,728 kg 3,857 kg 3,713 kg 3,638 kg

Propulsion System:Power 141 kW 175 kW 209 kW 129 kW 160 kW 191 kWEfficiency 70% 70% 70% 70% 70% 70%Isp 7,000 s 7,000 s 7,000 s 7,000 s 7,000 s 7,000 sThrust 2.87 N 3.57 N 4.27 N 2.62 N 3.26 N 3.89 NMass Flow Rate 4.19E-05 kg/s 5.20E-05 kg/s 6.22E-05 kg/s 3.82E-05 kg/s 4.74E-05 kg/s 5.67E-05 kg/s

Asteroid:Mass 1.0E+10 kg 1.0E+10 kg 1.0E+10 kg 1.0E+10 kg 1.0E+10 kg 1.0E+10 kgAcceleration 2.87E-10 m/s^2 3.57E-10 m/s^2 4.27E-10 m/s^2 2.62E-10 m/s^2 3.26E-10 m/s^2 3.89E-10 m/s^2Total Deflection V 1.00 cm/s 1.00 cm/s 1.00 cm/s 1.00 cm/s 1.00 cm/s 1.00 cm/s

Spacecraft MassInitial Mass 23,953 kg 23,809 kg 23,728 kg 21,857 kg 21,713 kg 21,638 kgEOM Mass (Dry Mass) 18,000 kg 18,000 kg 18,000 kg 18,000 kg 18,000 kg 18,000 kg

Launch VehicleType Delta 4050H Delta 4050H Delta 4050H Delta 4050H Delta 4050H Delta 4050HLift Capability to Starting Conditions 21,000 kg 21,000 kg 21,000 kg 9,000 kg 9,000 kg 9,000 kgLaunch Margin -2,953 kg -2,809 kg -2,728 kg -12,857 kg -12,713 kg -12,638 kg

2/21/13 3/11/13 3/23/13

Results for Asteroid V = 1.0 cm/s

11.5 km/s 10.8 km/s 10.6 km/s Revised numbers

5,182 kg 4.953 kg 4,884 kg Revised numbers

Revised numbers-2,182 kg -1,953 kg -1,884 kg

Revised numbers for 2004KE1 via personal communication with Lou D’Amario/JPL

1.89 yrs 1.81 yrs 1.77 yrs Revised numbers

4.63 yrs 4.00 yrs 3.59 yrs Revised numbers

Results for Asteroid V = 0.2 cm/s

Initial Spacecraft Acceleration 0.12 mm/s^2 0.15 mm/s^2 0.18 mm/s^2 0.12 mm/s^2 0.15 mm/s^2 0.18 mm/s^2

Starting Condition 1000 km LEO 1000 km LEO 1000 km LEO C3 = 0 km2/s2 C3 = 0 km2/s2 C3 = 0 km2/s2

Date:Departure 7/11/11 11/28/11 2/28/12C3 = 0 km2/s2 3/1/13 3/17/13 3/28/13Asteroid Rendezvous 2/10/18 2/24/18 2/15/18 3/18/18 3/1/18 2/19/18EOM 5/6/18 5/3/18 4/13/18 6/19/18 5/15/18 4/23/18

Time Duration:Spiral Out to C3 = 0 km2/s2 1.64 yrs 1.30 yrs 1.08 yrs N/A N/A N/AInterplanetary Transfer 4.95 yrs 4.94 yrs 4.89 yrs 5.07 yrs 4.97 yrs 4.91 yrsAsteroid Deflection 0.23 yrs 0.19 yrs 0.16 yrs 0.26 yrs 0.21 yrs 0.17 yrsTotal Mission Duration 6.82 yrs 6.43 yrs 6.12 yrs 5.32 yrs 5.18 yrs 5.08 yrs

V Requirements:Spiral Out 6.507 km/s 6.459 km/s 6.418 km/s N/A N/A N/AInterplanetary Transfer & Rendezvous 7.564 km/s 7.198 km/s 7.006 km/s 7.784 km/s 7.331 km/s 7.095 km/sStatistical Navigation 0.200 km/s 0.200 km/s 0.200 km/s 0.200 km/s 0.200 km/s 0.200 km/s

Propellant Requirements:Spiral Out 2,036 kg 2,010 kg 1,991 kg N/A N/A N/AInterplanetary Transfer 2,137 kg 2,028 kg 1,971 kg 2,203 kg 2,068 kg 1,997 kgStatistical Navigation 53 kg 53 kg 53 kg 53 kg 53 kg 53 kgAsteroid Deflection 291 kg 291 kg 291 kg 291 kg 291 kg 291 kgTotal Propellant 4,518 kg 4,383 kg 4,307 kg 2,547 kg 2,412 kg 2,342 kg

Propulsion System:Power 132 kW 165 kW 197 kW 121 kW 150 kW 180 kWEfficiency 70% 70% 70% 70% 70% 70%Isp 7,000 s 7,000 s 7,000 s 7,000 s 7,000 s 7,000 sThrust 2.70 N 3.36 N 4.02 N 2.47 N 3.06 N 3.66 NMass Flow Rate 3.94E-05 kg/s 4.89E-05 kg/s 5.85E-05 kg/s 3.59E-05 kg/s 4.46E-05 kg/s 5.33E-05 kg/s

Asteroid:Mass 1.0E+10 kg 1.0E+10 kg 1.0E+10 kg 1.0E+10 kg 1.0E+10 kg 1.0E+10 kgAcceleration 2.70E-10 m/s^2 3.36E-10 m/s^2 4.02E-10 m/s^2 2.47E-10 m/s^2 3.06E-10 m/s^2 3.66E-10 m/s^2Total Deflection V 0.20 cm/s 0.20 cm/s 0.20 cm/s 0.20 cm/s 0.20 cm/s 0.20 cm/s

Spacecraft MassInitial Mass 22,518 kg 22,383 kg 22,307 kg 20,547 kg 20,412 kg 20,342 kgEOM Mass (Dry Mass) 18,000 kg 18,000 kg 18,000 kg 18,000 kg 18,000 kg 18,000 kg

Launch VehicleType Delta 4050H Delta 4050H Delta 4050H Delta 4050H Delta 4050H Delta 4050HLift Capability to Starting Conditions 21,000 kg 21,000 kg 21,000 kg 9,000 kg 9,000 kg 9,000 kgLaunch Margin -1,518 kg -1,383 kg -1,307 kg -11,547 kg -11,412 kg -11,342 kg

2/21/13 3/11/13 3/23/13

11.5 km/s 10.8 km/s 10.6 km/s Revised numbers

3,352 kg 3,217 kg 3,141 kg Revised numbers

Revised numbers-352 kg -217 kg -141 kg

Revised numbers for 2004KE1 via personal communication with Lou D’Amario/JPL

1.89 yrs 1.81 yrs 1.77 yrs Revised numbers

3.76 yrs 3.30 yrs 3.01 yrs Revised numbers

• Mission meets Prometheus goals for testing engine and power systems with modest demands

• Mission can be accomplished by 2015 using early spiral Prometheus capability

• Mission opens multiple exploration doors– Demonstrates capability to protect planet– Opens capability for in situ resource exploitation– Offers excellent in situ science opportunity

• Deflection of NEAs can only be done using Prometheus technologies

Rationale and Considerations

Rationale and Considerations

• Public safety and planetary protection goal offer superior rationale for use of nuclear reactor in space– Within a decade there will be growing public

concern about potential asteroid impacts due to a major increase in the discovery rate of 100 meter class NEOs

– Public safety cannot be assured re NEO impacts without the use of the Prometheus technologies including nuclear power and high performance propulsion

Title

B612 is an attractive alternative for Prometheus 1:● Less than one third the ΔV required

for JIMO

● No extreme radiation environment

● Robust exploration goals that are well-matched to Vision for Space Exploration objectives and that are embraced and readily understandable by the public

Questions & Discussion