At approximately 3:26PM ET yesterday, NASA's Messenger probe slammed into the planet Mercury at speeds of around 8,750 mph or 2.5 miles per second. The picture above is the last image it beamed back to Earth before ending its 10-year mission, four years of which were spent orbiting Mercury, the solar system's smallest planet.
Although the craft ran out of fuel weeks ago, NASA scientists made the final adjustments to its destructive flight path by venting the helium gas used to pressurize its fuel tanks. The 3-meter-long Messenger became the first spacecraft to crash into Mercury — adding a crater estimated to be five times its size to the planet's pockmarked surface. John Grunsfeld, the associate administrator of NASA's Science Mission Directorate, described it as "going out with a bang."
An illustration of Messenger moving into orbit around Mercury. (NASA)
"A NASA planetary exploration mission came to a planned, but nonetheless dramatic, end Thursday when it slammed into Mercury's surface at about 8,750 miles per hour and created a new crater on the planet's surface," said NASA in an official statement. "Messenger's lonely demise on the small, scorched planet closest to the sun went unobserved because the probe hit the side of the planet facing away from Earth."
Messenger completed its primary mission in 2012 but kept on flying for three more years
Messenger's end may have been unobserved, but it was not uncelebrated. The craft was originally launched in August 2004 and began orbiting Mercury in March 2011. Although it completed its primary science objectives in March 2012, its mission was extended twice to send back even more detailed images and video of Mercury, rewriting our understanding of the planet. Messenger's work helped determine the composition and history of the planet, as well as confirming that its polar regions contained both ice and organic material.
"Today we bid a fond farewell to one of the most resilient and accomplished spacecraft to ever explore our neighboring planets," said Sean Solomon, Messenger's principal investigator. "The Messenger mission has surpassed all expectations and delivered a stunningly long list of discoveries that have changed our views — not only of one of Earth's sibling planets, but of the entire inner solar system."