The orbiter has operated longer than any other spacecraft ever sent to Mars. It has returned more information about Mars than all earlier missions combined and has succeeded far enough beyond its original mission to see two later NASA orbiters arrive: Mars Odyssey and Mars Reconnaissance Orbiter.
This is truly unfortunate. The rovers have been real troopers, outlasting their mission objectives, but the Orbiter has really been the unsung hero of the research projects. Let us hope the engineers can coax it back to functioning.
