SoylentNews is people
SoylentNews
Submission Preview
NASA Rejects Plan to Send Dawn to Another Asteroid
From SpaceNews [spacenews.com] we learn that NASA announced yesterday (July 1) that the Dawn spacecraft will remain in orbit around the dwarf planet Ceres. Project officials had proposed sending Dawn to the asteroid 145 Adeona, a main belt asteroid about 150 kilometers across that Dawn would fly by in May 2019.
From the article:
Jim Green, director of NASA's planetary science division, said in a statement that the decision to keep Dawn at Ceres was driven by the science it would provide in the opinion of the senior review panel. "The long-term monitoring of Ceres, particularly as it gets closer to perihelion -- the part of its orbit with the shortest distance to the sun -- has the potential to provide more significant science discoveries than a flyby of Adeona," he said.
Carol Raymond, deputy principal investigator for Dawn, said in a June 28 presentation at a meeting of the Small Bodies Assessment Group (SBAG) at the Johns Hopkins University Applied Physics Laboratory that the project proposed the Adeona flyby because they believed visiting a different asteroid would be of more interest than remaining at Ceres.
Dawn, she noted, had completed all of its main scientific priorities at Ceres earlier this year. "I think we've gotten so much already that the incremental amount of knowledge that we would gain would be maybe not as great as one would have thought," she said of an extended mission at Ceres.
The extended mission was made possible by efforts to conserve the spacecraft's supply of hydrazine, begun in 2012 while in orbit around the asteroid Vesta. Hydrazine is used for station keeping (orbital maneuvers made by thruster burns that are needed to keep a spacecraft in a particular assigned orbit) and attitude control thrusters.
"The team worked very hard to execute an aggressive and persistent campaign to preserve the hydrazine," Raymond said, crediting "exceptionally smooth" operations of the spacecraft that limited consumption of the fuel. "In 2016, we ended up not only achieving our intended mission, but with a surplus which we can now use to do something else."
