Surface exploration of small solar system bodies:challenges and prospects

Marco Pavone

Autonomous Systems Laboratory

Department of Aeronautics and Astronautics

Stanford University

Email: pavone@stanford.edu

Website: http://www.stanford.edu/~pavone/index.html

July 4, 2013

Galaxy Forum USA 2013

M. Pavone, Stanford Aero/Astro In-situ small bodies exploration 1

pavone@stanford.eduhttp://www.stanford.edu/~pavone/index.html

Space rovers

How would you change the design for low gravity environments?

M. Pavone, Stanford Aero/Astro In-situ small bodies exploration 2

Space rovers

How would you change the design for low gravity environments?

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Small bodies

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Small bodies exploration so far

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Future: its all about close proximity observations...

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...and sampling...

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...in risky areas...

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...and very specific regions...

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...at multiple sites

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Concepts for in-situ exploration: static platforms

Philae lander

Payload of ESAs Rosettaspacecraft (2014)

Designed to land on Comet67P/Churyumov-Gerasimenko

Comet hopper

Mission to comet46P/Wirtanen

Preselected for a NASADiscovery-class mission in 2011

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Concepts for in situ exploration: mobile platforms

Wheeled rovers: Nanorover

Designed by NASA-JPL forHayabusa mission (2000)

Project cancelled

Spring-actuated hoppers: PROP-F

Payload for Phobos 2 Sovietmission (1988)

Mission failed JPL also developed three

generations of spring-actuatedhoppers

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Concepts for in situ exploration: mobile platforms

Internally-actuated hoppers:MINERVA

Payload of JAXAs Hayabusamission (2003)

Deployment failed

Internally-actuated hoppers:MASCOT

Payload of JAXAs Hayabusa 2 Developed by DLR To be launched in 2014

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Spacecraft/rover hybrids for small bodies exploration

Develop a mission architecture that allows the systematic andaffordable in-situ exploration of small Solar System bodies

Key idea: minimalistic, internally-actuated mobile robotic platforms

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Joint work with R. Allen (Stanford), J. Castillo (JPL), J. Lang (JPL), I. Nesnas (JPL), N. Strange(JPL), and J. Hoffman (MIT).Funded by 2011 NASA NIAC program.

Robotic platform

Key philosophy: Exploit low gravity, rather than facing it as a constraint

Minimalistic platform specifically designed for microgravity:Systematic exploration (all access mobility, versatility and scalability)3 mobility options: 1) tumbling, 2) hopping, 3) pseudo-orbital flight

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Basic concept

Basic concept: Swapping angular momentum

H = Iplatform platform +3

i=1

Iflywheel,i flywheel,i

Reaction torque

Rotating flywheel

Robot enclosure

Attitude-controlled hop

Torque generated by flywheel

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momentum.movMedia File (video/quicktime)

Prototypes and test beds

Prototypes:

Motor Controller

Motor & Encoder

Brake

Flywheel

Processor

Can Adapter

Batteries

DC/DC Converter

Test beds:

Spinning mass Air-bearing platform

Tilted table

Emulated gravity

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Reference mission to Phobos

Main questions:

1 What is the origin of Phobos materials?

Phobos comes from Mars?Phobos is a captured asteroid?

2 Water and organics at Phobos?

Blue spectral unit water-rich?Putative phyllosilicates associated withorganics?

3 What is the structure of Phobos soil?

Degree of maturation of the regolith?

4 What is the nature of the surfacedynamics?

Degree of mobility of the soil?

Dark dust

Phobos bulk material?

Image small crater structure

Ejecta from impactor?

Search for block ejecta

?

Fine-Scale Sampling of Phobos Surface Diversity

5Km

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Mission operations

1 Initial reconnaissance of object

2 Deployment of hybrid

3 Initial free roaming by hybrid4 Command and execute guided rolling/hopping trajectories via

synergistic mission operationshybrid relies on the mothership for localization/trajectory planning

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HandBrake 0.9.8 2012071700

architecture.mp4Media File (video/mp4)

Conclusion

Robotic exploration of small bodieswill be one of the main NASA objectives in the years to comerequires disruptively new mobility concepts ad hoc for low gravityenvironments

Spacecraft/rover hybrids:new paradigm for in-situ exploration of small bodiestechnology to obtain new science at an affordable costproof of concept successfully demonstrated

Contact: pavone@stanford.eduWebsite: http://www.stanford.edu/~pavone/index.html

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pavone@stanford.eduhttp://www.stanford.edu/~pavone/index.html