Searching for Satellites of Ceres: Support for the Dawn Mission
Abstract
The existence of satellites, or lack thereof, around Ceres is of great interest to the Dawn mission, which is currently en route to Ceres and will arrive in February 2015. The Dawn spacecraft will orbit Ceres at altitudes of 1180 to 6400 km, well within the satellite stability region. The final opportunity for observations of Ceres with HST prior to Dawns arrival occurs in April 2014, when Ceres makes a close pass at opposition to Earth. In addition to providing additional targets for exciting physical studies by the Dawn instruments, satellites, if there were any, would substantially affect Dawns orbit planning in order to accommodate observations and ensure spacecraft safety. For example, detection of satellites would allow this program to derive a more accurate measurement of the mass of Ceres, which is important for the mission planners to determine the orbit of spacecraft. With the observation planning process already underway, early detection of satellites will provide sufficient time to adapt mission plans to be able to observe any satellites on ingress or during the mapping orbits. Timing is particularly important, since the spacecraft now has use of only two reaction wheels, which is already impacting mission design, and which prevents Dawn from conducting its own deep satellite search as was accomplished prior to arrival at Vesta. Because of this, an HST survey is critical for Dawn operations at Ceres. Since satellite detection could require a change to the missions nominal orbital strategy and present risk from dust associated with any satellites, it is crucial to put Dawn in the best position to succeed.
- Publication:
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HST Proposal
- Pub Date:
- October 2013
- Bibcode:
- 2013hst..prop13503S