The report is in on the loss of NASA's Mars Global Surveyor, which died in November 2006. To summarize: "Oops."
An oversight in writing procedures for the spacecraft led to its misalignment relative to the Sun and the loss of power to the solar panels. The craft expired when its backup batteries were gone.
On the plus side, the orbiter, launched in 1996, lasted four times as long as expected. NASA managers class the mission as a resounding success no matter how it ended.