A probe NASA has dubbed Dawn has arrived at the dwarf planet Ceres and is now orbiting it at an altitude of nearly 38,000 miles above the surface. While NASA scientists are certainly excited that Dawn has reached its destination, the data they are receiving currently is limited because the probe is over the asteroid’s night side.
Dawn powered by an ion engine
Kenneth Chang of The New York Times reports that the Dawn spacecraft is different than others because it is powered by an ion engine. This means that, unlike other spacecraft, Dawn’s engine is able to fire for longer periods at a time. Traditional spacecraft fire their engines for less than an hour in order to slow down and allow planets to pull them into orbit.
The ion engine that powers Dawn generates some thrust but is able to fire continuously for weeks, unlike other engines that can only be fired for a short time. As a result, Dawn’s course hasn’t changed much since it entered into orbit around Ceres.
Dawn to start examining Ceres
Toward the end of April, Dawn will be in a circular orbit that’s about 8,400 miles. At that point, the probe will begin examining Ceres closely and send data back to earth. Ceres is the biggest of the asteroids astronomers have found, which is why they now classify it as a dwarf planet. When it was originally discovered in 1801, astronomers classified it as a planet, although it was later downgraded to an asteroid classification and then upgraded to a dwarf planet classification.
The asteroid orbits the sun between Jupiter and Mars. Scientists are interested in the bright spots that are on the surface of Ceres. They suspect that those bright spots might be salt or ice patches.
Dawn visits the second of its two targets
According to NASA’s announcement, Dawn is the very first spacecraft to go to a dwarf planet. It is also the first one to be sent on a mission for the purpose of visiting two different targets. Between 2011 and 2012, the probe orbited Vesta, another huge asteroid that orbits the sun between Jupiter and Mars, collecting data and pictures and sending them back to Earth.
NASA’s Jet Propulsion Laboratory launched Dawn in September 2007. Since then, the probe has flown 3.1 billion miles to reach Ceres.
NASA and other space agencies have been known to tweet from the point of view of their spacecraft, and this time is no different:
— NASA’s Dawn Mission (@NASA_Dawn) March 6, 2015