Figure 3a. Simplified 3D surface mesh of the S/C including solar panels, lander, antenna, and various orbiter instruments. The resolution of the model can be adjusted to accommodate the available computational resources.

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Neutral gas and dust simulations around comet 67P/Churyumov-Gerasmenko and the spacecraft in support of ESA's Rosetta mission


Valeriy M. Tenishev, Martin Rubin, Kenneth C. Hansen, Michael R. Combi, Tamas I. Gombosi : University of Michigan


Simulations of the cometary environment are carried out at the University of Michigan based on requirements stated by the Rosetta working groups and agreed upon during the comet modeling team meetings at the International Space Science Institute (ISSI). The model runs of the dusty/gas coma have been performed for heliocentric distances in a range starting from 1.3 and up to 3.3 astronomical units, that represent the state of the coma during the mission including the period of the Rosetta lander deployment.

Neutral Gas & Dust Simulations


Figure 1



Modeled dust density around comet 67P/Churyumov Gerasimenko together with dust bulk flow streamlines. The total gas production rate is 2.05·1027 1/s and a dust production of 6 kg/s distributed with a r­‐4 law from 10-7 to 10­‐2 m. The angular dependence of the gas and dust production is distributed according to Tenishev et al. [Astrophys. J., 685, 659-­‐677, (2008)] and is predominantly sunward (left) directed.

Figure 2


The block based type mesh that is currently under development and planned to be used in our dust/gas coma simulations.


The nucleus mesh (above) [Lamy, Space Science Reviews, 128, 23–66, (2007)] includes all major topological features and local distribution of sources over its surface.



The volume mesh (above) will be used in the actual simulations. The major advantage of such meshes is that they are adjustable to the local features of the flow with a minimal increase in the number of computational cells.

Helium Leak Simulations


Figure 4



A simplified geometry of the spacecraft that can be used in our DSMC model. The model includes the main body of the spacecraft, lander, antenna and the solar panels. Shown is the inner boundary which is the spacecraft itself in black and two semi-­transparent cuts through the actual simulation mesh in blue (y=0 and z=0 planes).

Animation

Thanks to Andrea Accomazzo, Kathrin Altwegg and ESA for their assistance with the Helium Leak Simulations.

Simulated helium distribution around the Rosetta spacecraft during the helium pressurization test.


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