The first spacecraft ever to orbit Mercury will crash into the surface of the small planet located closest to the sun in just two short weeks from now.
NASA's Messenger Probe has been circling Mercury since 2011 gathering valuable data about the little known innermost planet. However, today it is almost out of fuel and now it plans to say goodbye in a truly dramatic fashion on April 30, assuming that one final orbit raising maneuver on April 24 goes off without a hitch, said mission team members.
"We will be impacting the surface on the 30th of April, around 1925 UTC [3:25 p.m. EDT]," mission systems engineer Dan O'Shaughnessy, of The Johns Hopkins University's Applied Physics Lab, said during a news conference Thursday.
"That impact will not be in view," he added. "It will happen during a planetary occultation, so the spacecraft will pass behind the planet, out of view of the Earth, and will just not emerge again."
Mercury itself is already covered by craters. However, the crater that is created by Messenger as it crashes into the surface is of particular interest to scientists, said Sean Solomon, the mission's principal investigator and director of Columbia University's Lamont-Doherty Earth Observatory.
Messenger's grave could help researchers better understand Mercury's rates of space weathering, which tends to turn bright, freshly exposed materials dark, Solomon said.
Unfortunately, ground based instruments will not be able to observe or study the crater, but the BepiColombo Mercury probe set for launch in 2017 and arrive in orbit of the planet in 2024 could.
The BepiColombo team "will be looking for signs of this crater, and if they can make measurements of it, they will know precisely how long that region has been exposed to space," Solomon said. "That will be an important study that comes a decade from now," he added.
The Messenger mission, whose name is short for MErcury Surface, Space ENvironment, GEochemistry and Ranging, launched in August 2004 and has cost $450 million. It is the only probe every to orbit Mercury and only the second craft to study the planet after the Mariner 10 probe flew by Mercury three times in 1974 and 1975.
Messenger achieved a great deal during its time in orbit helping scientists construct the best ever maps of the planet and even confirming the present of carbon and other organic compounds and water ice in permanently shaded craters near Mercury's poles.
"For the first time in history, we now have real knowledge about the planet Mercury that shows it to be a fascinating world as part of our diverse solar system," John Grunsfeld, associate administrator for NASA's Science Mission Directorate, said in a statement.
"While spacecraft operations will end, we are celebrating MESSENGER as more than a successful mission," he added. "It's the beginning of a longer journey to analyze the data that reveals all the scientific mysteries of Mercury."
