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Science Operations End For NASA’s Dawn Spacecraft

Nov. 1, 2018


This photo of Ceres and one of its key landmarks, Ahuna Mons, was one of the last views Dawn transmitted before it completed its mission. This view, which faces south, was captured on Sept. 1 at an altitude of 2220 miles (3570 kilometers) as the spacecraft was ascending in its elliptical orbit.

Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA


NASA’s Dawn spacecraft has gone silent, ending an 11-year odyssey that explored the two largest objects in the main asteroid belt, giant asteroid Vesta and dwarf planet Ceres. 

Dawn has run out of fuel, ending a mission on which dozens of Planetary Science Institute researchers have worked. The spacecraft signal was lost during a tracking pass with NASA's Deep Space Network early Wednesday morning. After the flight team eliminated other possible causes for the missed communications, mission managers concluded that the spacecraft finally ran out of hydrazine, the fuel key to enabling the spacecraft to control its pointing. This means that Dawn can no longer keep its antennae trained on Earth to speak or listen to mission control, and that it can no longer turn its solar panels to the sun for recharging. 

PSI CEO and Director Mark Sykes, a mission co-Investigator, was among those who developed the mission concept back in 1999. “This was the fifth proposal of our group, led by the Dawn PI Christopher T. Russell of UCLA, to promote the revolutionary capabilities of solar-electric propulsion in Solar System exploration,” said Sykes. “Our multiple asteroid rendezvous proposals were always anchored by Vesta, the source of basaltic meteorites on Earth. Once Ceres became available as a second target, we had a compelling case to compare the evolution of dry and water-rich protoplanetary bodies.” 

PSI Senior Scientist Thomas Prettyman, a mission co-Investigator, is the lead for the Gamma Ray and Neutron Detector (GRaND) investigation. He has been involved with Dawn for about 18 years in all mission phases, from concept through end of mission. 

Dawn offered scientists new insights into the early stages of our Solar System. “Dawn has carried out the first exploration of the main asteroid belt, providing a detailed understanding of the geology of Vesta and Ceres, once just faint glimmers of light in a telescope,” Prettyman said. 

While the Dawn spacecraft has stopped sending new information to scientists on Earth, researchers will have enough data from the mission to keep them busy for years. 

“While mission operations are ending, we still have quite a bit of work left to do, including archiving of data and publication of results,” Prettyman said. “Our team will continue to progress on analyzing and interpreting the new, low altitude data that we’ve acquired. The number of elliptical orbits and quality of data we’ve received has far exceeded our expectations.” 

Data acquired by Dawn indicate liquid water once flowed within Ceres’ interior and organic molecules have been detected on the surface. The presence of carbonaceous materials in a water rich environment has implications for astrobiology, warranting further investigation. “The planetary science community is discussing next steps for the exploration of Ceres. Dawn’s accomplishments are incredible. Nevertheless, there is a lot left to learn and I think there is great value in following up with another mission,” Prettyman said. 

Current PSI scientists who worked on the Dawn mission include Bruce Barraclough, Dan Berman, David Crown, William Feldman, Amara Graps, Margaret Landis, Lucille Le Corre, Jian-Yang Li, Scott Mest, Jeff Morgenthaler, Beatrice Mueller, David O'Brien, Eric Palmer, Thomas Platz, Thomas Prettyman, Robert Reedy, Norbert Schorghofer, Hanna Sizemore, Mark Sykes, Bryan Travis, Pasquale Tricarico, Naoyuki Yamashita and Aileen Yingst. PSI Alumni who worked on Dawn include Vishnu Reddy, Brent Garry and Lynnae Quick.





Alan Fischer

Public Information Officer


fischer [at]



Thomas Prettyman

Senior Scientist

(505) 690-5128

prettyman [at]


Mark V. Sykes



sykes [at]

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