Spirit has been stuck in a place NASA calls "Troy" since April 23 when the rover's wheels broke through a crust on the surface that was covering a bright-toned, slippery sand underneath. After a few drive attempts to get Spirit out in the subsequent days, it began sinking deeper in the sand trap. Driving was suspended to allow time for tests and reviews of possible escape strategies, NASA stated.
[spam URL stripped]"
Link to Original Source