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Space Shuttle: Difference between revisions
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→Active Thermal Control System
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The heat balance in space is also influenced by the orientation of the Shuttle relative to the Sun and Earth - sunward facing surfaces tend to heat up to 350 K whereas shaded surfaces may cool down to 150 K. To ensure ice-free thruster and other exhausts, electrical heating elements may therefore be needed. | The heat balance in space is also influenced by the orientation of the Shuttle relative to the Sun and Earth - sunward facing surfaces tend to heat up to 350 K whereas shaded surfaces may cool down to 150 K. To ensure ice-free thruster and other exhausts, electrical heating elements may therefore be needed. | ||
Orbiter heat management often combines cooling systems and attitude - for instance placing the OV into a tail to Sun inertial attitude minimizes incident heat and allows to cool the freon down so that it can act as a heat sink for about 15 minutes even without the radiator deployed, a technique known as 'cold soak'. Similarly, orienting the payload bay towards Earth ensures that even during the night, temperatures don't drop too much so that EVA work is possible. | |||
As of June 2015, the FG Shuttle includes a fairly sophisticated simulation of the heat balance, including incident heat flux from Sun and Earth dependent on surface normal and albedo, internally generated heat in the avionics bays, heat transport via conduction and via the cooling loops, radiated heat from the surfaces the action of the flash evaporators and the radiator. | |||
=== Main Propulsion System === | === Main Propulsion System === | ||