"Our job was to wear these rovers out exploring, to leave no unutilized capability on the surface of Mars, and for Spirit, we have done that."
— John Callas, MER project manager, 2011
"Just think of some of the things that have happened back on Earth [during Opportunity's mission]. The entire Obama Presidency. The entire existence of Facebook. The Boston Red Sox winning the World Series three times! We've been on Mars a very long time."
—Steve Squyres, MER principal investigator, 2016