Equipment for Keeping the Spacecraft at the Right Temperatures
Some parts of the spacecraft must be kept warm and other parts cold
to provide the right environments for the science instruments and onboard
equipment. The inside of the spacecraft is kept at 10°-20° Celsius
(50°-68° Fahrenheit) by covering it with thermal blankets made
from gold-plated aluminum-tin alloy.
Most of the instruments need to be kept at room temperature
(10°-20° Celsius or 50°-68° Fahrenheit), but two
instruments (PFS and OMEGA) have infrared detectors
that need to be kept at very low temperatures (about -180° Celsius
or -292° Fahrenheit). Radiators for these instruments release excess
heat into space, which is very cold (about -270° Celsius or -454
Fahrenheit). The sensors on the camera (HRSC) also need to be kept cool.
Material not covered by insulation such as the solar array and the
high-gain antenna may face temperatures of -100° Celsius
(-148° Fahrenheit) in the shade and up to 150° Celsius (302°
Fahrenheit) in sunlight. To keep these parts from shrinking and
expanding in such temperature variations, they are made of composite
materials that can withstand wide temperature variations, as it would
require too much power to keep them at room temperature.