NASA’s Dawn spacecraft made history at 4:39 a.m. PST Friday morning when it reached Ceres and became the first man-made object to orbit a dwarf planet.
According to NASA, the objective of the Dawn mission is to “study the asteroid Vesta and dwarf planet Ceres, celestial bodies believed to have accreted early in the history of the solar system. The mission will characterize the early solar system and the processes that dominated its formation.”
Dawn was launched from Cape Canaveral in September 2007, with an ultimate destination of the asteroid belt that lies between Mars and Jupiter. Dawn’s first target in the asteroid belt was Vesta. Dawn arrived there in 2011 and spent 14 months studying the protoplanet. Since leaving Vesta, Dawn has had a trajectory for its second and final destination: Ceres. No other spacecraft has ever orbited two separate targets.
"Since its discovery in 1801, Ceres was known as a planet, then an asteroid and later a dwarf planet," Dawn’s chief engineer Marc Rayman from Jet Propulsion Laboratory said in a press release. "Now, after a journey of 3.1 billion miles (4.9 billion kilometers) and 7.5 years, Dawn calls Ceres, home.”
Image: Path taken by Dawn from launch, to Vesta, to Ceres. Credit: NASA
Due to the current positioning of the spacecraft, images from Dawn will not be taken in full light until mid-April. Once it is facing the side illuminated by the sun, Dawn will begin to return high-resolution images.
Dawn’s primary science mission will continue through July of 2015. During this time, the spacecraft will analyze Ceres using a camera that images in visible wavelengths, spectrometry mapping in visible and infrared, as well as a gamma ray and neutron spectrometer.
Researchers will be able to compare data from Dawn with what was taken from Vesta in regards to their respective internal structures, gravitational fields, and other features. By learning more about the largest objects in our asteroid belt, scientists will gain insight into the formation of the planets in our solar system.
"We feel exhilarated," said principal investigator Chris Russell of the University of California, Los Angeles (UCLA). "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."