stuck at a location called Troy. And now it looks as though Spirit may not be leaving.
Over the last few weeks, scientists have been working desperately to try and free Spirit from Troy. Right now it is sitting on the top of rock, with its wheels sinking into the regolith*. All attempts to extract the rover so far have failed (there's as of yet no tow trucks on Mars), and scientists are running out of time before the Martian winter arrives. Temperatures are expected to drop to -40 degrees (Celsius and Fahrenheit), meaning Spirit will only survive if it has the energy to run its heaters. Just as the sun gets lower on the horizon during the winter here on Earth, the same thing happens on Mars. Spirit is going to have to get its solar panels pointing towards the sun in order to generate enough energy to survive. "Getting through the winter will all come down to temperature and how cold the rover electronics will get," said John Callas, project manager at JPL for Spirit and its twin rover, Opportunity. "Every bit of energy produced by Spirit's solar arrays will go into keeping the rover's critical electronics warm, either by having the electronics on or by turning on essential heaters."
If Spirit does survive, it will by no means just be a stuck piece of metal on Mars. Just as the Phoenix Mars lander was able to teach us much about current and past conditions on Mars, Spirit will just become a stationary science lab. One nice thing is that, of all the spots Spirit could have been stuck, Troy is quite a interesting one scientifically. There is a wide range of sediments and minerals that appear to be the product of a hydrothermal vent on ancient Mars. There is even the possibility of finding out if Mars has a liquid core by closely monitoring the tilt of Mars rotation. "There's a class of science we can do only with a stationary vehicle that we had put off during the years of driving," said Steve Squyres, a researcher at Cornell University and principal investigator for Spirit and Opportunity. "Degraded mobility does not mean the mission ends abruptly. Instead, it lets us transition to stationary science."
Spirit is not dead yet and its twin rover, Opportunity seems to be finding cool rock after cool rock. These rovers are still pouring out scientific discoveries. This intrepid duo have lasted more than 20 times their expected lifetimes, and have made tremendous finds into the history of Mars. And they still keep going.
Image taken by spirit on sol (a Martian day) 2154
*Cool word for dirt in places that don't have life (basically ground up rock)