科研之友
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摘要
Aerogravity-assist maneuvers have the potential to deliver spacecraft to a wide range of destinations within the solar system. The ultimate goal is to minimize the maximum lift-to-drag ratio that a vehicle must provide for a given mission. First, assuming an arbitrary maximum lift-to-drag ratio during the aerogravity assist as an initial guess (e.g., maximum L/D=3), a patched-conic solution is obtained for the interplanetary trajectory, yielding boundary conditions at the flyby planets. Second, the flythrough departure velocity at a given planet is maximized while meeting the required atmospheric turn angle to get to the next planet. Depending on whether the departure velocity at each planet is greater (or less) than required, the vehicle's maximum L/D is determined such that the aerogravity-assist maneuver matches the required departure velocity and turn angle. Then, the overall mission minimum value representing the vehicle's maximum L/D to complete a given tour is determined by taking the highest value (or limiting case) found from all of the aerogravity-assist flybys. As an example (and as a possible technology demonstrator) an Earth departure and return mission with flybys at Mars and Venus with a total flight time of 375 days and a maximum lift-to-drag ratio of 3.015 is constructed, enabling atmospheric sample returns from Earth's nearest neighbors.
- 出版日期2014-12
