Second stalled wheel may doom Mars rover New Scientist

A second wheel may now be broken on NASA’s Spirit rover, dampening hopes for freeing the robot from a sand trap it has been trapped in for seven months. The injury will also increase the rover’s risk of freezing to death in the coming winter.
Spirit has been struggling to escape from a patch of soft, sandy soil since April. Its three left wheels are almost entirely buried and have little traction, and its right-front wheel is of no use – it seized up permanently in 2006.
Now, Spirit’s right-rear wheel is also having problems and may be permanently disabled.