low risk asteroid capture october 1, 2013 howard eller asteroid initiative idea synthesis workshop...
TRANSCRIPT
Low Risk Asteroid Capture
October 1, 2013
Howard Eller
Asteroid Initiative Idea Synthesis Workshop
Approved for public release. NGAS Clearance case #13-1911.
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NASA Asteroid Initiative
Long Range Imager
Advanced CubeSat Impactor
Ground Penetrating Radar
LADAR
NG Systems Support Key Elements of NASA’s Asteroid Initiative
Ready for launch in 2017
A S T E R O I D I N I T I AT I V E
C A PA B I L I T I E S
T O D AY
Asteroid Deflection Vehicle
Asteroid Capture System
Presented by James MungerPresented by Steve Warwick
Integrated Sensing Systems
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Asteroid Capture Requirements
• Capture and de-spin an asteroid with the following characteristics: Size: 5 m < mean diameter < 13 mAspect ratio < 2/1 bMass: up to 1,000 metric tons Rotation rate: up to 2 rev/minute, any axesComposition, internal structure, & physical integrity unknown until after rendezvous & capture
• NASA is interested in a variety of asteroid capture system concepts &technologies, including:– Deployable & inflatable structures– Capture bags, robotic mechanisms,
modeling & simulation, telerobotic operations
• NASA is interested in concepts to separate & capture a small piece (1 m to 10 m) from a larger asteroid
Coh
esiv
enes
s
Rubble PileSmall Rock
Particle Size
Rubble PileLarge Conglomerate
MonolithicBasalt - Metallic
MonolithicSandstone
Capture system must address a broad set of Asteroid conditions
Image credit: NASA / JPL / Caltech
Image credit: JAXA
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Launch Options
• CaptureVehicle can launch on: Atlas V, Falcon Heavy, Delta-IVH, SLS
– Atlas-551 can inject the CaptureVehicle into LEO & the Falcon Heavy to escape
• An affordable launch reduces cost pressures for all other Asteroid mission elements
• SLS is heavily employed by the manned mission
Atlas 551 is NASA approved, while the Falcon Heavy saves transit time
Image credit: NASA
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Mission Overview
Integrated sensors, models and tele-operation enable autonomous capture
100km 10km 1km 100m 10m 0m
Ranging, Orbit & Spin Determination
• Hyperspectral Imaging
• LADAR
Surface & Structural Characterization
• LADAR• Ground Penetrating RADAR
Proximity Operation & Capture
• CubeSat Flybys
• CubeSat Impactors
Image credit: NASA / JPL / Caltech; JAXA
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Heritage Bus Capabilities
• Flight proven, in-production spacecraft, requiring minimal, changes for EP-transit & Asteroid Capture functions
• Heritage bus provides:
– >1000kg of bi-propellant for 6-DOF Proximity Operations near the Asteroid (additional thrusters required)
– Very high structural strength & ruggedness
– 4 M600 single gimbal CMG’s mounted in a bi-planar configuration with a 35 deg roof angle (300 N-m torque per CMG)
– 1850, 1600, 1300 N-m-sec cluster momentum storage capability about X, Y & Z
• 12,000kg Xenon EP module is added in place of an open truss adapter (other missions/buses can use this same module)
The Heritage Bus is no-risk and easily available for a 2017 launch
EP Module
AstroMesh Based AstroArray, Stowed, 2pl
Atlas V T3302 Truss Adapter (130-in.)
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Capture Vehicle System Capabilities
• AstroMesh derived solar arrays provide 50kW & high stiffness, high strength
• Instrument suite mounts on upper surfaces• Capture Vehicle matches dominant asteroid
rotation & slews to match asteroid precession minimizing relative motion & Asteroid surface disturbance, maximizes Science preservation
• Capture device consists of:– Conical asteroid contact cone– 2 AstroMesh derived AstroCapture halves rapidly
& fully enclose the asteroid– Imbedded webs tighten & secure
the asteroid for transport• Capture Vehicle auto tracks the Asteroid
contact point during the capture & securing process & then deactivates its ACS
CaptureVehicle autonomously contacts and secures Asteroid maximizing Science preservation
AstroMesh Based AstroCapture
Asteroid Capture Device, Closed
AstroMesh Based AstroCapture Asteroid Capture Device, Open
13m dia Asteroid
Capture Vehicle Approach and Sequence
1. Asteroid visually acquired & “co-orbits” along its v-bar
2. Asteroid tumble & mechanical make-up remotely analyzed
3. Rotation axis, precession, trajectories & capture timing determined
4. Progressive autonomous capture scenario dry-runs executed
Near contact approach without contact, back-away
Contact with contact point tracking without capture, back-away
Contact with sample removal but without capture
5. Contact, contact point track, 5 sec AstroCapture closure, rapid webs/cables tighten, autonomous safe assessment with release option
6. CaptureVehicle ACS autonomously turned off, single-body motion
7. Ground verifies safe & successful capture
8. Spacecraft ACS is ground activated, rotationstopped, vehicle oriented for sun-pointing & thrusting
9. EP- transfer begins
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Safe to Capture Achieved Prior to
Closure
AstroCapture Closed and Asteroid Secured by
Closure Webs
System can successfully address wide range of conditions
Image credit: NASA / JPL / Caltech
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Maximum Science, Minimum Risk Capture
• Existing, high capability bus provides robust, low-risk mission implementation
• Instrumented/gimballed cone provides “any-surface-condition” contact & contingency sample collection
• CaptureVehicle matches Asteroid motion to minimize surface disturbance & loss of science
• Progressive autonomous capture dry-runs verify hardware & software before capture
• Normal to surface “bagging” maximizes surface & science protection
• Capturing only after Asteroid is in place & relative motion minimized, maximizes capture certainty & allows rapid capture & easy abort & retry
Fully open geometry till ready to capture protects the mission & science
Filament or Electrostatic Gripper (JPL Gripper shown)
Capture Vehicle approaches along dominant spin axis matching Asteroid precession rate
Image credit: NASA / JPL / Caltech