NASA’s Dawn spacecraft has gone into orbit around Ceres, the first dwarf planet to be visited by a man-made object. Ceres is the largest object in the Solar System between Mars and Jupiter, believed to be a left over from the formation of the solar system.
The spacecraft was captured by the dwarf planet’s gravity at about 4:39 a.m. PST (7:39 a.m. EST) Friday, according to NASA’s announcement.
“Since its discovery in 1801, Ceres was known as a planet, then an asteroid and later a dwarf planet,” said Marc Rayman, Dawn chief engineer and mission director at JPL. “Now, after a journey of 3.1 billion miles (4.9 billion kilometers) and 7.5 years, Dawn calls Ceres, home.”
Since the beginning of the year, the spacecraft sent back to Earth surprising images of bright spots that could not be explained by scientists. NASA confirmed that something on Ceres reflects more sunlight, but Dawn was still too far. The most recent images received by NASA, taken on March 1, show Ceres as a crescent, mostly in shadow because the spacecraft’s trajectory, but when Dawn will emerge from Ceres’ dark side it will deliver ever-sharper images as it spirals to lower orbits around the planet.
“We feel exhilarated,” said Chris Russell, principal investigator of the Dawn mission at the University of California, Los Angeles. “We have much to do over the next year and a half, but we are now on station with ample reserves, and a robust plan to obtain our science objectives.”
Ceres is the largest body in the main asteroid belt, which lies between Mars and Jupiter, with an average diameter of 590 miles (950 kilometers), and is thought to contain a large amount of ice. Some scientists think it’s possible that the surface conceals an ocean.
NASA’s Dawn is also the first mission to orbit two extraterrestrial targets. From 2011 to 2012 it explored the giant asteroid Vesta, the second most massive body in the asteroid belt, for 14 months during 2011 and 2012. From more than 30,000 images sent by Dawn, scientists gained numerous insights about the geological history of this body and saw its cratered surface in fine detail. By comparing Vesta and Ceres, they will develop a better understanding of the formation of the solar system.