Wheels for lunar vehicles

The development of wheels for the Lunar Roving Vehicle

“…7). The phenomenon was not well understood and so several wire mesh wheels with different tread spacing, and hence different total tread coverage (ranging from 0 to 100 percent coverage), were built for comparative evaluation at the U.S. Army Waterways Experiment Station (WES) (Freitag 1972, Green 1971a,b/Melzer 1971. Wheel dynamometer testing was done on a lunar soil simulant (LSS), which emulated the mineralogy and particle distribution of lunar soil samples collected on the Apollo 11 and 12 missions.…”

“…The slope climbing ability of the LRV was also determined on the basis of the single-wheel drawbar pull results, using an empirical equation that correlated these data with measured vehicle climbing performance (Freitag 1970(Freitag /1972. Like in the drawbar pull evaluation, the 20 percent slip point was used as the maximum value in assessing gradeability.…”

“…-LRV climbing performance in loose, air-dry lunar soil simulant (LSS1, LSS2, LSS3, and LSS4). Climbing performance was predicted based on single-wheel tests using the correlation method proposed by Freitag (Freitag 1970(Freitag /1972. The mean trend was generated by curve-fitting the first and second pass data (simulating front and rear tires) separately using 3rd degree polynomials, then taking the average of the two curves.…”

Discrete element method analysis of single wheel performance for a small lunar rover on sloped terrain

“…There are only a few published reports on the interaction between wheels and planetary terrain such as lunar regolith. Freitag et al [4] investigated several flexible wheels of different tread patterns for the Apollo Lunar Roving Vehicle (LRV) and…”

“…LRV wheels were however much larger than those envisaged for our lunar micro rover. Their study of the wheel performance on a slope of prototype rover models used three metrics: the pull coefficient, torque coefficient, and the power number [4][5][6].…”