Page:Project Longshot - Advanced Design Program Project Report.pdf/57

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3.7 Thermal Control
There are two significant problems to consider in the thermal design:


 * There is a huge amount of waste heat from the propulsion system and the nuclear reactor (both fission and fusion reactions);
 * The fuel will be stored in large tanks at near-absolute temperatures, and must be shielded from the waste heat of the nuclear reactions.

The spacecraft will require highly efficient radiators to dissipate the thermal energy released by the interstellar drive, namely the inductors, particle beams, and fusion reaction. The radiation from this dissipation process will be reflected away from the rest of the spacecraft by a mirror specifically engineered to reflect infra-red energy. Additionally, conduction will be buffered by special ceramic materials between the power and propulsion units.

The nuclear reactor will dump its waste heat to the same radiators used by the propulsion unit. Ceramic buffers will also be located between the power unit and the fuel tanks.

The fuel tanks will contain pelletized helium and deuterium which must be shielded from conductive and radiative heat energy. During the initial phase of the mission the tanks will be shielded from the sun by a shroud which will be blown off at a sufficient distance from the sun where the solar radiation becomes negligible. The mirrors and ceramic buffers will keep the spacecraft's waste heat away from the tanks, while refrigeration units will keep the fuel vapor pressure