Science Forums 2

[Janus]

Quick correction. While the Moon's Sidereal(fixed star to fixed star) period is 27.5 days, the synodic (local noon to local noon) period is 29.531 days. The day/night terminator thus travels at 15.4 km/h. Not much of a difference, but every little bit could help.

For comparison, the Apollo mission rovers had a top speed of 13 km/hr and and averaged 9.6 km/h.

The rover used about 1000w for the drive and steering motors and massed (fullly loaded) 700kg.

After a little search I found some 80w solar panels, each weighing 7.7 kg, you would need 13 of these to provide 1000w (with some reserve) bringing the mass of the panels to 100 kg. The panels cover an area of 7.8 m² or about 3 m x 2.6 m. The rover was 3m x 2.3m. The panels would extend just a little past the rover main body. This seems reasonable.


This is, of course, only gets you the top speed of the rover running at full tilt, which is about 18% shy of the average speed you would need to maintain. Since you need to allow for time to circumnavigate large obstacles (and thus a higher max speed), and extra power requirements for climbing inclines, etc., you will want to scale up the solar panels (add in the fact that the panels are only warranted for 76w max power.)

Then there is the consideration of just maintaining 15.4 km/hr over the rough Lunar surface. At 1/6g hitting a bump will cause 2.5 times more "bounce" than hitting the same bump at the same speed on Earth. Or put another way, it would be the equivalent of hitting the same bump at 38.5 km/hr on the Earth. And remember, this is the average speed you must maintain. at times you will have to travel faster to make up for detours etc.

OTOH, if you want to make just one trip around the Moon, and can tilt your panels to catch the most sunlight, you can try this trick:

Start your rover about 45° "ahead" of the Sun and then allow the Sun to creep forward to 45° ahead of the rover. This gives you 40 days of Sunlight to run on, bringing your required average speed down to 11.4 km/sec.