NASA'S MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) spacecraft has ended its phenomenally successful mission in the most fitting manner imaginable. The probe, which had maintained a lonely vigil over the desolate planet for more than four years, smashed into the surface of Mercury, the planet that had surrendered countless secrets to the robotic explorer this Thursday at 3:26:02 pm EDT.
One would struggle to define the MESSENGER mission as anything less than a resounding success. Over the course of its time in orbit around Mercury, the probe has granted us innumerable insights into the characteristics of the barren planet, including its composition, structure, and the nature of its magnetosphere.
All of this was achieved under the protection of what was at the time of launch a cutting-edge Sunshade, which, for 4,104 orbits, fended away solar radiation that would have otherwise made short work of the delicate equipment stored within the spacecraft.
NASA Graphics displaying predictions of the spacecraft's impact region (Image: NASA, Johns Hopkins University Applied Physics Laborator, Carnegie Institution of Washington)
But having exhausted its supply of propellent, and left to the whim of solar gravity, the spent probe had no choice but to end its watch. At the time of colliding with Mercury, the spacecraft was on the far side of the planet relative to Earth. This meant that the team members, who had spent years of their lives administering to the probe, where unable to follow its final descent. However, they will undoubtedly be comforted by the wealth of information, and over 270,000 images that MESSENGER had collected over the course of its operational life.
MESSENGER's final resting place is now marked by a crater 16 m SG in diameter, formed as the spacecraft crashed into the surface of Mercury at speeds exceeding 8,700 mph (14,000 km/h) – not a bad way to go.