'Best. Mars. Mission. Ever.' Scientists hail MAVEN's legacy as NASA retires Red Planet orbiter

NASA officials and members of the MAVEN mission team celebrate the probe's successful arrival in Mars orbit on Sept. 21, 2014.

MAVEN's Imaging UltraViolet Spectrograph obtained images of rapid cloud formation on Mars between July 9-10, 2016. The ultraviolet colors of the planet have been rendered in false color, to show what we would see with ultraviolet-sensitive eyes. Mars' tallest volcano, Olympus Mons, appears as a prominent dark region near the top of the image, with a small white cloud at the summit that grows during the day. Three more volcanoes appear in a diagonal row, with their cloud cover (white areas near center) merging to span up to a thousand miles by the end of the day.