Ten months after the Spirit Mars Exploration Rover got stuck in the Martian sand after it broke through a crusty surface and churned into soft sand hidden underneath NASA engineers have given up on attempts to free it. NASA will now focus on preparing the now stationary rover to survive the oncoming Martian winter that starts in May. When the Mars winter is over Spirit will be used as a stationary research platform. NASA’s press release describes some possible uses:
One stationary experiment Spirit has begun studies tiny wobbles in the rotation of Mars to gain insight about the planet's core. This requires months of radio-tracking the motion of a point on the surface of Mars to calculate long-term motion with an accuracy of a few inches. Tools on Spirit's robotic arm can study variations in the composition of nearby soil, which has been affected by water. Stationary science also includes watching how wind moves soil particles and monitoring the Martian atmosphere.
Spirit’s sister rover, Opportunity is still active has completed one third of a 12 mile trek begun in mid-2008 to a large crater called Endeavour.