Concept of Inflatable Outer Wheel Rover for Exploration of Lunar and Planetary Holes and Subsurface Caverns

Abstract

Three huge vertical holes have been found on the Moon and their scientific explorations are planned by the UZUME (Unprecedented Zipangu (Japan) Underworld of the Moon Exploration) Project. For such explorations, a rover with large wheels is preferred for climbing over bumps. However, the exhaust materials from landers or rovers should be avoided to prevent contamination of the terrain. This paper proposes a rover with inflatable tubes that function as outer wheels. A prototype with one degree of freedom was built. The inflatable wheel was 1000 mm in diameter and 400 mm in width, and weighed 2.0 kg. A small cart, which was used as a weight, was moved on the torus to revolute the rover. Each cart weighed 0.5 kg. The performance of the rover was tested and compared with the calculated results. The climbable step height and slope angle were statistically calculated and were independent of gravity. The climbable step height and slope angle were 15 mm and 9°, and they almost agreed with the calculated results.