It's been a long and hard road for NASA's Messenger Probe as it studied the surface of Mercury for the last four years. That journey, however, will come to an end today, after NASA announced that the craft will crash land into the planet at around 3:30pm ET today. The vehicle was the first that managed to make it to Mercury, and has been in service for more than a decade -- far longer than administrators had ever expected it to last. In fact, the project was only meant to last for a year, but canny fuel-saving measures managed to quadruple its lifespan.
Update: The deed is done. At 3:15pm ET the Messenger probe said goodbye to its friends and family, then quite ceremoniously smashed in to the surface of Mercury. The probe is survived by countless siblings and cousins, including New Horizons (Pluto), Juno (Jupiter), Cassini (Saturn), Maven (Mars), Dawn (asteroid Vesta and Ceres) ARTEMIS P1/P2 (the Moon), and the 2001 Mars Odyssey (Mars, obviously).
[Image credit: NASA/JHU APL/Carnegie Institution of Washington]