Launched in 2007, the NASA spacecraft Dawn is scheduled to arrive at the dwarf planet Ceres in the asteroid belt between Mars and Jupiter on March 6. You can read more about the spacecraft and its mission on the NASA website. But here’s a quick recap.
Following the launch, Dawn used a gravity-assist from Mars to arrive at the asteroid Vesta on July 16, 2011. It studied Vesta from orbit until Sept. 5, 2012 before departing for Ceres. Above is a photo taken by Dawn of Vesta’s south pole that shows the crater Rheasilvia (click to enlarge). Vesta is a spherical body with a diameter of 525 km. The crater, meanwhile, is 460 km wide and 13 km deep. So on an asteroid that small it’s a pretty major feature. Five per cent of all meteorites that have fallen on Earth, in fact, are thought to have originated from the collision that created the crater around a billion years ago.
Vesta is a rocky body, while Ceres, which has a diameter of around 950 km, is believed to have large quantities of ice. Upon arriving at the dwarf planet, Dawn will enter orbit and use its instrument array (a framing camera, visual and infrared spectrometer, and gamma ray and neutron detector) to search for elements such as oxygen, magnesium, aluminum, titanium, iron, potassium, uranium, and water.
Dawn’s already thrown NASA scientists a bit of a curve ball by detecting two puzzling bright spots situated side-by-side in a crater on Ceres. As the probe moves closer to the dwarf planet, it will be able to investigate the spots further and perhaps make other surprising discoveries.
Dawn will study Ceres until its hydrazine fuel supply is exhausted, and it will then become a permanent satellite of the dwarf planet.