At 3:30pm ET on April 30, 2015, and after four years of studying, NASA’s Messenger Probe crashlanded the surface of Mercury. After being in service for more than a decade, it is the first vehicle to ever make it to Mercury. However, it didn’t leave without saying goodbye.
Messenger lasted far longer than administrators ever hoped. The project was only meant to succeed for about a year, but due to fuel-saving measures its life span was quadrupled.
In its time studying Mercury, Messenger learned a lot about the little planet: It learned that there’s ice and organic matter close to the planet’s poles. It found an unexpected high concentration of magnesium and calcium on Mercury’s night side. Messenger also found visual evidence of past volcanic activity as well as evidence to a liquid iron planetary core. Aside from the probe constructing the most detailed map of Mercury’s surface, it also discovered that Mercury’s magnetic field was offset far to the north of the planet’s center.
It was a long life for Messenger, but at 3:15pm ET the probe said goodbye and proceeded to smash a 16 meter crater on the planet’s surface. Unfortunately, there was no way to view this since it all took place on the side facing away from us.
Messenger is survived by several other NASA relatives: New Horizons (Pluto), Juno (Jupiter), Cassini (Saturn), Maven (Mars), Dawn (asteroid Vesta and Ceres), ARTEMIS P1/P2 (the Moon), and the 2001 Mars Odyssey.