NASA's Dawn reaches Ceres, becomes first spacecraft to orbit dwarf planet
Mission controllers at NASA鈥檚 Jet Propulsion Laboratory received confirmation that the Dawn spacecraft had achieved orbit around the dwarf planet Ceres Friday.
This processed image, taken Jan. 13, 2015, shows the dwarf planet Ceres as seen from the Dawn spacecraft. The image hints at craters on the surface of Ceres. Dawn's framing camera took this image at 238,000 miles (383,000 kilometers) from Ceres.
NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
NASA astronomers and engineers breathed a sigh of relief Friday morning, as the Dawn spacecraft became the first Earthly vessel to achieve orbit around a dwarf planet.
Mission controllers at NASA鈥檚 Jet Propulsion Laboratory in Pasadena, Calif., received confirmation from the craft at 5:36 Pacific time, NASA reported.
鈥淎fter a journey of 3.1 billion miles and 7.5 years, Dawn calls Ceres, home," Dawn鈥檚 chief engineer Marc Rayman said in a press release Friday morning.
The 3.1-billion-mile journey included a 14-month layover on the asteroid Vesta, the second largest object in the asteroid belt between the orbits of Mars and Jupiter. Ceres is the largest, not quite big enough to be considered a planet.
Astronomers are hoping that data gathered by Dawn from Ceres and Vesta will offer clues to understanding the conditions that existed in the region when the planets were forming some 4.56 billion years ago, the Monitor鈥檚 Pete Spotts reported Thursday.
These are 鈥渢wo intact protoplanets from the very dawn of the solar system,鈥� JPL planetary scientist Carol Raymond said during a briefing Thursday as Dawn closed in on Ceres鈥檚 orbit. 鈥淭hey are two fossils we can investigate to understand what was really going on at that time.鈥�
Ceres is believe to be 25 percent water ice. Researchers have speculated that the presence of that ice could suggest that the dwarf planet hosted liquid water early in its history, Mr. Spotts reported.
Dawn's measurements of surface features, especially the shapes and sized of the numerous craters that pock the surface, will provide an important test of this hypothesized blueprint for Ceres' structure.
The relatively high abundance of water ice researchers attribute to Ceres has raised the intriguing possibility that the dwarf planet briefly hosted liquid water in early its history, as radioactive decay from minerals in a rocky core heated the underside of the ice layer and melted it.
This could have provided a habitat for microbial life, notes Dr. Raymond.
Dawn鈥檚 visit to Ceres鈥檚 orbit is planned to last until June 2016. In that time, the craft will circle the dwarf planet at varying altitudes.
鈥淲e feel exhilarated,鈥� said Chris Russell, principal investigator of the Dawn mission at the University of California, Los Angeles, in JPL鈥檚 release. 鈥淲e have much to do over the next year and a half, but we are not on station with ample reserves, and a robust plan to obtain our science objectives.鈥�
听For more information about those science objectives, read Pete Spotts鈥檚 full coverage of the historic approach.