Spacecraft/Rover Hybrids for the Exploration of Small Solar System Bodies

The goal of this project is to develop a mission architecture that allows the systematic and affordable in-situ exploration of small Solar System bodies, such as asteroids, comets, and Martian moons. Our architecture relies on the novel concept of spacecraft/rover hybrids, which are surface mobility platforms capable of achieving large surface coverage (by attitude-controlled hops, akin to spacecraft flight), fine mobility (by tumbling), and coarse instrument pointing (by changing orientation relative to the ground) in the low-gravity environments (micro-g to milli-g) of small bodies. The actuation of the hybrids relies on spinning three internal flywheels, which allows all subsystems to be packaged in one sealed enclosure and enables the platforms to be minimalistic, thereby reducing the cost of the mission architecture. The hybrids would be deployed from a mother spacecraft, which would then act as a communication relay to Earth and would aid the in-situ assets with tasks such as localization and navigation.

Collectively, this project aims to demonstrate that exploration via controlled mobility in low-gravity environments is technically possible, economically feasible, and would enable a focused, yet compelling set of science objectives aligned with NASA's interests in science and human exploration. The project is primarily funded by the NASA Innovative Advanced Concepts program.

This webpage contains digital copies of related publications, slides from the NASA NIAC Symposium 2012, movies of our experiments, information about our team, and more.

Spacecraft/rover hybrids in a nutshell

Mission architecture 

One mother spacecraft would deploy to the surface of a small body one (or more) spacecraft/rover hybrids. Once deployed, the hybrids would hop for long-range traverses and tumble to reach specific locations for in-situ measurements. The mother spacecraft would act as a communication relay to Earth and would aid the in-situ assets with tasks such as localization and navigation.

Spacecraft/Rover Hybrid 

Each hybrid is sealed in one enclosure and internally actuated through three mutually orthogonal flywheels.

Experimental validation

Gantry test bed 

This project leverages the Stanford 6 DoF microgravity test bed. The test bed is capable of emulating microgravity down to 0.0005 g and within a 1.5m x 3m x 1m workspace. The active gantry control together with passive compliance allows smooth motion tracking even during impulsive force inputs (as seen during hopping and ground collisions).

Parabolic campaign 

Sample maneuvers from the 2015 parabolic flight campaign. Such experimental campaign, involving more that 180 parabolas for a total of  90 minutes of microgravity, arguably provided the most advanced validation of microgravity robots to date.

Publications

  • A detailed report about the project [report]

  • Slides presented at the NASA NIAC 2015 Symposium [Presentation]

  • Slides presented at the NASA NIAC 2012 Symposium [Presentation]

In the press

Movies

Team

This project brings together a strong team of experts in astronautics, human-space flight, science, and engineering from Stanford, JPL and MIT, and engages graduate students at both Stanford and MIT.

Marco Pavone 

Marco Pavone
Assistant Professor, Principal Investigator
Stanford University
Department of Aeronautics and Astronautics

Julie Castillo 

Julie C. Castillo-Rogez
Planetary Scientist, Co-I and JPL lead
NASA Jet Propulsion Laboratory
Planetary Science

Andreas Frick 

Andreas Frick
Systems Engineer, Co-I
NASA Jet Propulsion Laboratory

Benjamin Hockman 

Benjamin Hockman
Graduate Student, GN&C lead
Stanford University
Department of Aeronautics and Astronautics

Jeffrey Hoffman 

Jeffrey A. Hoffman
Professor (and former NASA astronaut), Co-I
Massachusetts Institute of Technology
Department of Aeronautics and Astronautics

Issa Nesnas 

Issa A. D. Nesnas
Technical group supervisor, Co-I
NASA Jet Propulsion Laboratory
Robotic Software Group

Robert Reid 

Robert Reid
Research Technologist, Localization lead
NASA Jet Propulsion Laboratory
Robotic Software Group

Additional collaborators at Stanford: Ross Allen, Daniel Washington, Lawrence Leung, Adam Koenig, Nicholas Cheung, Ben Kirshner, John McMordie

Additional collaborators at JPL: Mark Amash, Gareth Meirion-Griffith, Elizabeth Carey, Jacklyn Green, Loris Roveda, Christine Fuller, Chris McQuin, Tam Nguyen (JPL/MIT)