Dawn's Mission At Ceres
| Autor: | Daniel J. Grebow, Gregory J. Whiffen, John C. Smith |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
020301 aerospace & aeronautics
Spacecraft Ion thruster Computer science business.industry Dwarf planet Astronomical unit 02 engineering and technology 01 natural sciences Reaction wheel Attitude control 0203 mechanical engineering Asteroid 0103 physical sciences Aerospace engineering Interplanetary spaceflight business 010303 astronomy & astrophysics |
| Zdroj: | AIAA/AAS Astrodynamics Specialist Conference. |
| DOI: | 10.2514/6.2016-5375 |
| Popis: | Dawn is NASA's ninth Discovery class mission. The Dawn spacecraft was designed to orbit both the giant asteroid Vesta and the dwarf planet Ceres in succession, a mission only made possible by the high efficiency of ion propulsion. While the same spacecraft visited both bodies, the mission planning and maneuver execution at the two bodies were necessarily very different. The mission at Vesta benefited from at least three functioningreaction control wheels. At Ceres, all maneuvering and coasting during transfers was done without reaction wheel control due to the loss of the second of four wheels while departing Vesta. Loss of the second wheel made conserving attitude control propellant (hydrazine) critical to achieving mission success at Ceres. To save hydrazine, avoiding unnecessary coasting and attitude turns became essential during the interplanetary cruise to Ceres and for all transfers once at Ceres. In contrast, operations at Vesta did not need to avoid coasting. Operating at Ceres requires being farther from the Sun. Greaterheliocentric distances (approaching 3 AU (Astronomical Units) make Dawn's attitude control constraints while maneuvering more restrictive as a result of reduced control authority. |
| Databáze: | OpenAIRE |
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