You also have to account for the difference in atmospheric pressure on Mars in determining how the laser operates up there. NASA showed an image in which the plasma resulting from a laser shot on Mars is noticeably larger on Mars compared to Earth.
I am guessing just running the motors (to move the vehicle) requires a fair amount of energy (due to martian soil resistance). Factor in that a standard PC uses about a 100 Watt Power Supply and the 110Watt Supply suggested by someone above would not allow for running the whole computing system, driving, and firing the laser simultaneously(it wouldn't make for a nifty sci-fi movie) ;-) !
The rock was close by since Curiosity hasn't yet moved. NASA characterized the first laser activation as "target practice" intended to calibrate the instrument. The rock, affectionately named "Coronation" (NASA branding is getting a little out of hand), presented a relatively large, flat side to ChemCam, so scientists reasoned it was a good first target. No work on laser energy levels. We'll try to find out.
This experiments sound awesome, and just wondering out of personal "curiosity" (grin),
what power/energy levels are these laser shots and what is a safe distance to shoot that kind of instrument. I am hoping that there won't be any surprises, ;-)
Curiosity fired its laser at a fist-sized Martian rock for the first time this past weekend. Curiosity's "ChemCam" fired 30 pulses of laser light at the nearby rock for 10 seconds. ChemCam is designed to catch the resulting light with its telescope, then analyze it with three onboard spectrometers to gather information on the composition of the rock sample. The principal investigator on the experiment reports NASA got "lots of signal."