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Cycler
A cycler is a potential spacecraft on a closed transfer orbit that would pass close to two celestial bodies at regular intervals. Cyclers could be used for carrying heavy supplies, life support and radiation shielding. Concept A cycler encounters two or more bodies regularly by employing a free-return trajectory, this trajectory was analysed by Arthur Schwaniger in 1963 with a symmetrical orbit past the Moon and Earth. Once the orbit is established, no propulsion is required to shuttle between the two, although some minor corrections may be necessary due to small perturbations in the orbit. The use of cyclers was considered in 1969 by Walter M. Hollister, who examined the case of an Earth–Venus cycler. Hollister did not have any particular mission in mind, but posited their use for both regular communication between two planets, and for multi-planet flyby missions. Triple cycler An extension of a cycler is the triple cycler like an Earth-Venus-Mars cycler, or a Jovian syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permanence (novel)
''Permanence'' is a 2002 science fiction novel by Canadian writer Karl Schroeder. Plot The novel tells the story of two characters, Rue Cassels and Michael Bequith, and their encounter with an alien spacecraft Rue has named ''Jentry's Envy.'' Schroeder uses the story as a venue for discussing the information economy and philosophy. Rue, on the run from her brother Jentry and out of money, files claim on an undiscovered comet. She expects to profit from the mineral rights, but it turns out that the "comet" is actually an interstellar cycler, a ship that travels in a light-years length orbit, at relativistic speeds (85% c) carrying cargo and passengers between the Halo Worlds, planets that orbit brown dwarf stars. The discovery causes a sensation, since the ship is the first to approach the planet Erythrion in ten years. Eventually her claim is upheld, since the cycler is silent, and her mineral rights become salvage rights, making her potentially very wealthy. A rich cousin of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free-return Trajectory
In orbital mechanics, a free-return trajectory is a trajectory of a spacecraft traveling away from a primary body (for example, the Earth) where gravity due to a secondary body (for example, the Moon) causes the spacecraft to return to the primary body without Spacecraft propulsion, propulsion (hence the term ''free''). Many free-return trajectories are designed to intersect the atmosphere; however, periodic versions exist which pass the moon and Earth at constant periapsis, which have been proposed for cyclers. Earth–Moon The first spacecraft to use a free-return trajectory was the Soviet Luna 3 mission in October 1959. It used the Moon's gravity to send it back towards the Earth so that the photographs it had taken of the far side of the Moon could be downloaded by radio. Symmetrical free-return trajectories were studied by Arthur Schwaniger of NASA in 1963 with reference to the Earth–Moon system. He studied cases in which the trajectory at some point crosses at a right ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |