Yesterday NASA announced that after over a year of silence from the Mars rover Spirit, which has been on Mars for about 7 years, they are hanging their hats and listing her as MIA.
Spirit landed on Mars in January of 2004 for a mission that was to last 3 months. Since then it has gathered quite a bit of data including evidence that Mars may have been wetter in the past then it is now. In March of 2010 Spirit stop sending signals which some believe was the result of a particularly harsh Martian winter which did not allow Spirit to get the solar rays it needed for power. Without an adequate supply of power the electronics in Spirit would have been particularly susceptible to the extreme cold.
Looking forward the NASA Rover Team is preparing to launch the next generation Rover called Curiosity this November which will gather data to determine if Mars ever has or ever will support microbial life.
I know that I will not forget Spirit or Oppertunity because they are one of the first NASA Missions that peaked my interest and a true testiment to modern day engineering.