Spacecraft/rover hybrids for the exploration of small Solar System bodies

Abstract

Abstract-In this paper we present a mission architecture for the systematic and affordable in-situ exploration of small Solar System bodies (such as asteroids, comets, and Martian moons). At a general level, a mother spacecraft would deploy on the surface of a small body one, or several, spacecraft/rover hybrids, which are small (< 5 kg, ≈ 15 Watts), multi-faceted robots enclosing three mutually orthogonal flywheels and surrounded by external spikes (in particular, there is no external propulsion). By accelerating/decelerating the flywheels and by exploiting the low gravity environment, the hybrids would be capable of performing both long excursions (by hopping) and short traverses to specific locations (through a sequence of controlled "tumbles"). Their control would rely on synergistic operations with the mother spacecraft (where most of hybrids perception and localization functionalities would be hosted), which would make the platforms minimalistic and in turn the entire mission architecture affordable. Specifically, in the first part of the paper we present preliminary models and laboratory experiments for the hybrids, first-order estimates for critical subsystems, and a preliminary study for synergistic mission operations. In the second part, we tailor our mission architecture to the exploration of Mars' moon Phobos. The mission aims at exploring Phobos' Stickney crater, whose spectral similarities with C-type asteroids and variety of terrain properties make it a particularly interesting exploration target to address both high-priority science for the Martian system and strategic knowledge gaps for the future human exploration of Mars.

Dynamics and Control of a Hopping Robot for Extreme Environment Exploration on the Moon and Mars

“…Others such as the Cyclops 9 and the inflatables pivot a heavy mass, thus moving center of gravity that results in rolling. Other mobility techniques including use of spinning flywheels attached to a two-link manipulator on the Gyrover 10 or 3-axis reaction wheels to spin and summersault as with the Hedgehog developed by Stanford and NASA JPL 27 . Hedgehog's use of reaction wheels enables it to overcome rugged terrain by simply creeping over the obstacle no matter how steep or uneven 27 .…”

“…Other mobility techniques including use of spinning flywheels attached to a two-link manipulator on the Gyrover 10 or 3-axis reaction wheels to spin and summersault as with the Hedgehog developed by Stanford and NASA JPL 27 . Hedgehog's use of reaction wheels enables it to overcome rugged terrain by simply creeping over the obstacle no matter how steep or uneven 27 . However, it's unclear if a gyro based system can overcome both steep and large obstacles.…”

Path planning and navigation inside off-world lava tubes and caves

“…Others such as the Cyclops and the inflatables pivot a heavy mass, thus moving center of gravity that results in rolling. Other mobility techniques including use of spinning flywheels attached to a two-link manipulator on the Gyrover [10] or 3-axis reaction wheels to spin and summersault as with the Hedgehog developed by Stanford and NASA JPL [11]. Hedgehog's use of reaction wheels enables it to overcome rugged terrain by simply creeping over the obstacle no matter how steep or uneven.…”

Soft Tensegrity Systems for Planetary Landing and Exploration

“…These works are part of an exciting and broader field of aerospace research concerned with the design of efficient rovers for the exploration of Solar System bodies. The low-gravity environment and rough surfaces characteristic of small Solar System bodies offer new possibilities and challenges that must be met with clever designs that rely on different modes of locomotion than the traditional wheeled rover, which is inappropriate for such environments (Pavone et al 2013;Hockman et al 2017).…”