A NASA spacecraft and probe and the first chosen for NASA's Scout program—an initiative for smaller, lower-cost, competed spacecraft. Phoenix launched on 4 August 2007 and landed in the northern polar region of Mars (between 65 and 75 degrees latitude) on 25 May 2008. The lander deployed a robotic arm to dig trenches into the layers of water ice present there. Phoenix analysed soil samples collected by the robotic arm in search of the chemicals of life. Phoenix's stereo camera built up a three-dimensional picture of its surroundings while meteorology instruments scanned the Martian atmosphere up to 20 km in altitude, obtaining data about the formation, duration, and movement of clouds, fog, and dust. It also measured temperatures and atmospheric pressure.

The mission concluded on 10 November 2008, when engineers lost contact with the craft. NASA declared the lander officially dead in May 2010, when a new image transmitted by the Mars Reconnaissance Orbiter revealed signs of severe ice damage to the lander's solar panels. Nevertheless, the Phoenix spacecraft succeeded in its investigations and exceeded its planned lifetime.