OH NO… Opportunity’s needs a time out.
http://www.msnbc.msn.com/id/24300717/
Seeing as they’re on their 17th lifetime, a few glitches like this would be expected.
And since there’s no 80" cylinder on Mars, there should be no problem leaving the arm extended. :rolleyes:
pssshhh… Gaint Pistons always work!
(our last two robots have had giant pistons :D)
Not enough air on Mars.
Did Spirit and Opportunity fit into the cylinder in the first place?
There isn’t???!?! Gee, that will be a real surprise to all the atmospheric scientists working on the project. 
-dave
.
How much air is there (compared to earth)?
Depending on the season, latitude, and altitude, the average surface atmospheric pressure varies between 6 and 9 millibars.
It may not seem like much (it isn’t), but the Martian atmosphere is more than dense enough to allow effective use of parachutes during the entry-descent-landing process by multiple spacecraft.
And, yes, pistons will work just fine on Mars.
-dave
.
There was a compressor developed for Mars with no moving mechanical parts (other than valves to control the flow of ambient and pressurized gas). Overnight (when it’s cold) carbon dioxide is adsorbed in a porous material inside a pressure tank through a valve open to the Mars atmosphere. During the day (when it’s warmer and electrical power from solar arrays is available) the valve is closed and heaters are used to drive off the CO2 from the adsorber. Pressure in excess of one Earth atmosphere could be produced this way. This concept was developed for an experiment intended to demonstrate the production of oxygen on the surface of Mars.