1. 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

2. Space rovers
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3. Space rovers
How would you change the design for low gravity environments?
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4. Small bodies
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5. Small bodies exploration so far
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6. Future: it’s all about close proximity observations...
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7. ...and sampling...
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8. ...in risky areas...
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9. ...and very specific regions...
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10. ...at multiple sites
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11. Concepts for in-situ exploration: static platforms
Philae lander
• Payload of ESA’s Rosetta
spacecraft (2014)
• Designed to land on Comet
67P/Churyumov-Gerasimenko
Comet hopper
• Mission to comet
46P/Wirtanen
• Preselected for a NASA
Discovery-class mission in 2011
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12. Concepts for in situ exploration: mobile platforms
Wheeled rovers: Nanorover
• Designed by NASA-JPL for
Hayabusa mission (2000)
• Project cancelled
Spring-actuated hoppers: PROP-F
• Payload for Phobos 2 Soviet
mission (1988)
• Mission failed
• JPL also developed three
generations of spring-actuated
hoppers
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13. Concepts for in situ exploration: mobile platforms
Internally-actuated hoppers:
MINERVA
• Payload of JAXA’s Hayabusa
mission (2003)
• Deployment failed
Internally-actuated hoppers:
MASCOT
• Payload of JAXA’s Hayabusa 2
• Developed by DLR
• To be launched in 2014
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14. Spacecraft/rover hybrids for small bodies exploration
Develop a mission architecture that allows the systematic and
affordable 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.

15. 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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16. Basic concept
Basic concept: Swapping angular momentum
H = Iplatform ωplatform +
3
i=1
Iflywheel,i ωflywheel,i
Reaction torque
Rotating flywheel
Robot enclosure
Attitude-controlled hop
Torque generated by flywheel
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17. Prototypes and test beds
Prototypes:
Motor Controller
Motor & Encoder
Brake
Flywheel
Processor
Can Adapter
Batteries
DC/DC
Converter
Test beds:
β
Spinning mass Air-bearing
platform
Tilted table
Emulated gravity β
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18. 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 with
organics?
3 What is the structure of Phobos soil?
Degree of maturation of the regolith?
4 What is the nature of the surface
dynamics?
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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19. Mission operations
1 Initial reconnaissance of object
2 Deployment of hybrid
3 Initial “free roaming” by hybrid
4 Command and execute guided rolling/hopping trajectories via
synergistic mission operations
hybrid relies on the mothership for localization/trajectory planning
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20. Conclusion
• Robotic exploration of small bodies
will be one of the main NASA objectives in the years to come
requires disruptively new mobility concepts ad hoc for low gravity
environments
• Spacecraft/rover hybrids:
new paradigm for in-situ exploration of small bodies
technology to obtain new science at an affordable cost
proof of concept successfully demonstrated
Contact: pavone@stanford.edu
Website: http://www.stanford.edu/~pavone/index.html
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