The annual lunar soil hauling requirement is approximately 4X106 kg (see app. 5E) to replicate a new 100-ton seed each working year, so,
- m = (4X106 kg)/(3.14X107 sec) = 0.127 kg/sec
Hence, mining robot mass is
- M = (1.2)(0.127 kg/sec)(28,800 sec) = 4400 kg
(Approximately 4400 kg/1.2 = 3700 kg of lunar material are transported each cycle.) Note that M is the total mass of robots required, not necessarily the mass per robot. In fact, it is essential that the seed carry at least two such machines so that strip mining can proceed almost continuously given a 50% duty cycle and so that a "spare" is always available in emergency situations. Assuming linear downscaling the mass of each robot is 2200 kg.
In Carrier's strip-mining system the machines require an average of 0.3 W/kg. Mostly this is due to the hauling function, the most energy-intensive operation performed. Hence each mining robot requires about 660 W which may be drawn from 4 m2 of photovoltaic solar cell panels mounted on every available surface. A fuel cell module (Fickett, 1978) is included in the robot design, for buffer storage and peak load coverage when power consumption may rise as high as 10 kW (as during rescue operations). This module may be recharged at any time from the LMF power grid, but this should not be necessary as the robots should be fully self-sufficient in this regard. Finally, an electrostatic lunar dust wiper is provided to maintain solar cells and camera lenses at maximum efficiency.
