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