Every instrument and system on board Parker Solar Probe (with the exception of four antennas and a special particle detector) will be hidden from the sun behind a breakthrough thermal protection system (TPS)—an eight-foot diameter shield that the spacecraft uses to defend itself against the intense heat and energy of our star.
Every system will be protected, that is, except for the two solar arrays that power the spacecraft. When the spacecraft is closest to the sun, the solar arrays will be receiving 25 times the solar energy they would while orbiting Earth, and the temperature on the TPS will reach more than 2,500°F (1,370°C). The cooling system will keep the arrays at a nominal temperature of 320°F (160°C) or below.
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