Estimate the rate at which heat needs to be supplied to an astronaut repairing the Hubble telescope in space. Assume that the emissivity of the spacesuit is 0.5. Describe your model with a simple sketch and clearly state your assumptions.
GIVEN
• An astronaut repairing the Hubble telescope in space.
• Emissivity of spacesuit (?) = 0.5
FIND
• Rate at which heat needs to be supplied to the astronaut.
ASSUMPTIONS
• The spacesuit is idealized as a cylindrical object of height 1.8 m and diameter of 0.4 m.
• Temperature of 370C is maintained inside the suit.
SKETCH
We have, Area of the suit
With body temperature of T= 370C (310 K) and surrounding temperature of Ts= 0 K,
Heat radiated per unit area is given by
Thus total heat radiated from body is
Qtotal= 261 W/m2*5.53 m2 = 1447 W
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