NASA's Dawn spacecraft has made it as the first man-made space probe to orbit around a dwarf planet.
The spacecraft was about 38,000 miles from Ceres when the dwarf planet's gravity captured it on Friday, March 6 at 7:39 a.m. EST, with mission controllers at NASA's Jet Propulsion Laboratory (JPL) receiving the confirmation at 8:36 a.m.
Images taken by Dawn on March 1 show Ceres as a crescent that is mostly in shadow, which can be attributed to the spacecraft's trajectory that placed it on the side that faces the sun. Once it emerges from the dark side of Ceres in April, however, Dawn will be able to take sharper images as it spirals to the dwarf planet's lower orbit.
"We feel exhilarated," said Dawn mission principal investigator Chris Russell from 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."
Much about Ceres is shrouded in mystery but now that Dawn has orbited the dwarf planet, scientists are excited to glean valuable information. Among the things that experts hope to get from Dawn is the evidence of a subsurface liquid ocean on the alien world as this is currently unclear. The Herschel space telescope has detected water vapor around the dwarf planet, suggesting possible water plumes, but Dawn has not detected any so far.
Scientists also hope that with the arrival of Dawn on its second target alien world, it will provide explanations for the mysterious bright spots that can be seen in earlier images taken by the probe of the dwarf planet.
One idea posited for this feature is that these spots are reflective patches of ice that get exposed. The spots likewise have been observed to become brighter when the sun rises and dims when the sun sets. Russel said that if these icy spots have minerals such as salts and carbonates, it would indicate that the dwarf planet has liquid water.
Ceres will start sending data and images from its second target object, the largest known in the asteroid belt, by late April this year. By then, it will map the dwarf planet's surface, analyze its chemical composition, and come up with the most accurate measurement of the mass of Ceres. Scientists hope the probe could provide information that could tell about the beginning of the solar system.
