There's other science to be done, but scientists are most anxious for Dawn to find out what those bright spots are. Photo by NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
PASADENA, Calif., March 3 (UPI) -- As NASA's Dawn probe continues its approach to the dwarf planet Ceres, engineers back on Earth are preparing to initiate the scientific portion of the mission -- primarily, the search for water.
In 2014, the European Space Agency's Herschel space observatory detected plumes of water vapor rising from Ceres' surface. NASA scientists are hoping Dawn can confirm their suspicions that Ceres' surface protects a layer of icy water.
After being slung into orbit around Ceres on Friday, March 6, Dawn will ping the dwarf planet with radio waves to give scientists a better sense of what's beneath the surface. Dawn will also analyze Ceres' tenuous atmosphere.
But perhaps the most anticipated answer is: what is responsible for the two mysterious bright spots?
When they were first spotted, NASA scientists suggested they could be ice volcanos, or cryovolcanos. But that explanation is looking increasingly unlikely.
"A cryovolcano will likely result in a constructional feature," Carol Raymond, Dawn's deputy project scientist, said at a press conference held in Pasadena, California, on Monday.
"So we'd expect to see a mounded feature on the surface -- some sort of deposit around a central vent or a crack," Raymond added. "In the case of this crater, what we can say is that the brightest spot is not associated with a 'positive relief feature' -- i.e. a mound or peak ... so a cryovolcano is not at the top of the list for that feature."
The more popular and newly emerging theory is that the bright spots are impact-derived. This would make sense, given that they appear in the bottom of a crater. It's possible, Raymond and her colleagues say, that impacts could expose and melt subsurface ices -- vaporizing them and leaving a glistening sheen.
"Perhaps we're seeing a deposit that was left behind, which is rich in material like salts," she added.
The Dawn mission will also offer scientists a look at some of the first formed objects in the solar system.
"Studying Ceres allows us to do historical research in space, opening a window into the earliest chapter in the history of our solar system," Jim Green, director of NASA's Planetary Science Division, said in a press release. "Data returned from Dawn could contribute significant breakthroughs in our understanding of how the solar system formed."