Centaur Environment and Surface Activity Measurement Experiment (Cesame)
Abstract
CESAME is a NASA medium-class (i.e., New Frontiers-class) mission concept study in which a spacecraft will rendezvous with 29P/Schwassmann-Wachmann 1, an active Centaur that dynamically connects objects in the Kuiper Belt with the population of Jupiter Family Comets. While orbiting the sun in a relatively circular orbit beyond Jupiter (an eccentricity of ~0.04 and a semi-major axis of 6 AU), far enough from the Sun where water ice does not sublimate effectively, the ~ km-radius nucleus of this comet has exhibited consistent outgassing activity with regular outbursts. CESAME's science goals include determining how Centaur's outgas, geologically evolve, and store and lose volatiles. These goals can be achieved by using four complementary and well-understood investigations: (1) hyperspectral imaging, (2) active impactor experiment, (3) radar sounding/gravity measurements, and (4) mass spectrometry.
For a spacecraft to rendezvous with 29P, we derived multiple trajectory solutions that use a Jupiter gravity assist with Chemical Propulsion (CP) or Solar Electric Propulsion (SEP). For both cases, the departure would be on January 23, 2030, and the launch C3 is km2/sec2. For the CP case, the spacecraft arrives at 29P on March 4, 2039 with a velocity change at Jupiter of 0.23 km/sec and that at 29P of 3.02 km/sec. For the SEP case, the spacecraft arrives at 29P of September 23, 2039. This trajectory can be achieved with a thrust of 10 mN and a specific impulse (Isp) of 1900 sec. A backup launch opportunity exists, departing on August 29, 2035, and arriving on November 4, 2045. The velocity change at Jupiter is 0.10 km/sec, while that at the arrival is 2.71 km/sec. The launch C3 is km2/sec2. The mission plan is divided into four proximity operation phases. After arrival, the spacecraft will conduct global mapping at low resolution to determine the mass, rotation, and shape, as well as safety conditions. Then, it will perform global mapping at high resolution to observe geological and geophysical features and outgassing. Next, it will conduct an active impact experiment to characterize an ejecta plume while avoiding hypervelocity collisions with impact ejecta. Finally, it will observe the artificially produced impact crater to identify young layers and primordial structures.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMP089...05H
- Keywords:
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- 2194 Instruments and techniques;
- INTERPLANETARY PHYSICS;
- 6094 Instruments and techniques;
- PLANETARY SCIENCES: COMETS AND SMALL BODIES;
- 5794 Instruments and techniques;
- PLANETARY SCIENCES: FLUID PLANETS