NASA said yesterday (April 6, 2015) that the Dawn spacecraft has performed flawlessly, continuing to thrust with its ion engine as planned, since its capture by the gravity of dwarf planet Ceres on March 6. The thrust, combined with Ceres’ gravity, is gradually guiding the spacecraft into a circular orbit around the dwarf planet. All of the spacecraft’s systems and instruments are in excellent health, NASA said.
NASA had told us a month ago that new images would be coming in early April, and we are continuing to receive questions about the bright area on Ceres, shown in the Dawn photo below, which was taken on February 19.
No new images of this area yet, but if you want to follow the news about the spots, look to Marc Rayman – who is the Dawn spacecraft’s chief engineer and mission director at NASA’s Jet Propulsion Laboratory – and who is doing a fantastic job blogging Dawn updates at dawnblog.jpl.nasa.gov.
In Rayman’s most recent blog post (March 31, 2015), he writes that:
Even after it entered orbit, Dawn’s momentum carried it to a higher altitude, from which it is now descending. From March 2 to April 9, so much of the ground beneath it is cloaked in darkness that the spacecraft is not even peering at it. Instead, it is steadfastly looking ahead to the rewards of the view it will have when its long, leisurely, elliptical orbit loops far enough around to glimpse the sunlit surface again.
When will that be? In the first of the planned images, on April 10, the dwarf planet will appear as a thin crescent. The next images will come on April 14 and are expected to reveal a slightly larger crescent in even greater detail. Rayman writes:
… on April 14 (and extending into April 15), Dawn will obtain its last navigational fix before it finishes maneuvering. Should we look forward to catching sight of the bright spots then?
In truth, we do not yet know. The spots surely will be there, but the uncertainty is exactly where ‘there’ is.
We still have much to learn about a dwarf planet that, until recently, was little more than a fuzzy patch of light among the glowing jewels of the night sky.
Learn a lot more from Rayman about Dawn’s orbit around Ceres, and what scientists expect to find, at his blog.
In the meantime, know that – over the past month – Dawn has been following its planned trajectory on the dark side of Ceres, the side facing away from the sun. After orbital insertion, as Dawn’s momentum carried it to a higher altitude above the dwarf planet, it reached a maximum of 46,800 miles (75,400 kilometers) in altitude on March 18.
Yesterday, NASA said, Dawn was about 26,000 miles (42,000 kilometers) above Ceres, descending toward the first planned science orbit – labeled RC3 in the second diagram below – which will be 8,400 miles (13,500 kilometers) above Ceres’ surface.
Bottom line: People are asking when we will see closer images of those two bright spots on the dwarf planet Ceres. Dawn has been orbiting above Ceres’ night side, but will get its next images of the dayside – and maybe the bright spots – around mid-April. Scientists aren’t sure because the surface of Ceres has never been explored in detail. Dawn, which began orbiting Ceres on March 6, 2015, will provide the first-ever images!
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.