Apr 30, 2015 12:13 PM
Doomsday at Mercury: NASA craft close to falling into planet
The Associated Press
CAPE CANAVERAL, Fla. (AP) NASA's Messenger spacecraft is ending its four-year tour at Mercury with a crash landing.
Messenger is expected to slam into Mercury Thursday afternoon. It will be traveling more than 8,750 mph (14,081 kph) when it plunges from orbit, creating a crater an estimated 52 feet (16 meters) across.
Messenger became the first spacecraft to orbit hot, little Mercury, in 2011. Since then, it's circled the solar system's innermost planet 4,104 times and collected more than 270,000 images.
Flight controllers managed to keep the spacecraft going in recent weeks by using helium gas not originally intended as fuel. But now the gas is gone and gravity is tugging. The crash will occur on the side of Mercury facing away from Earth and telescopes.
Johns Hopkins University: http://messenger.jhuapl.edu/