Inescapable Heat

The astronauts could not have withstood the intense radiation on the surface of the moon whether it be infrared (heat) or other electromagnetic radiation.  Just considering the heat radiation alone, standing in the direct sunlight, the space suits would have been incapable of maintaining the immense temperature differential (with reference to body temperature) as the temperature in the sunlight would be far greater than what we experience here on Earth. The temperature on the sunlit surface of the moon is at least 250 degrees F. which is well above the boiling point of water. In short, there would be no effective means of stopping the build-up of heat.  Convection as a means of dissipating heat wouldn't work as there is no atmosphere on the moon.  

Some argue that the cold temperatures in the shadows would allow a fluid circulating in the astronaut's spacesuit to maintain body temperature as the fluid flows from the hot side of the spacesuit to the cold side; however, there wouldn't be a "cold" side of an astronaut's spacesuit on the sunlit surface of the moon--both sides would be hot!  

Cold and heat in space only exist insofar as there is matter involved. As everyone knows, temperature is a function of the kinetic energy of matter.  In the vacuum of space there is no matter and therefore space itself has no inherent temperature.  A body in space is cold only because it emits radiation faster than it absorbs or generates it; not because the space around it is somehow inherently cold.  On the sunlit surface of the moon, the shadow side of an astronaut's spacesuit could only be cold if it radiated heat faster than it absorbed it; but how can this happen when the surface of the moon in direct sunlight is both reflecting and emitting intense solar radiation back onto the shadow side of the astronaut's spacesuit?  Have you ever noticed the heat radiated from the hot sand all around you at the beach on a hot (100 degree F) summer day?  On one side, the astronaut is bombarded by direct solar radiation; on the other, he's bombarded by indirect solar radiation!  Aside from the small amount that radiates back into space, where exactly is the built-up heat going to go?  

NASA asserts that the Apollo spacesuits actually employed an evaporative cooling technology to cool the astronauts on the surface of the moon; however, as Ralph Rene points out, the astronauts' personal life support system or PLSS didn't contain sufficient water to account for the amount of time they spent on the surface of the moon (up to 4 hours at a time).1  The total amount of water carried by the Apollo astronauts was only 4 liters (and some of that obviously had to be utilized for drinking)!2  Imagine standing on the airless surface of the moon bathing in temperatures of at least 240 degrees F.  How is less than a liter of water going to keep you cool for an hour?  Indeed, how could any kind of personal cooling unit function under these conditions and still be small enough to fit into an astronaut's backpack which, by the way, must also contain other life support essentials not to mention one hell of a battery?  

Again, here I've only touched on the difficulties caused by heat radiation.  I leave consideration of other, more severe electromagnetic radiation the astronauts and their suits would have had to contend with on the surface of the moon to the reader.  See chapters 6 and 15 of Rene's NASA Mooned America.  


1. Ralph Rene, NASA Mooned America!, p. 100

2. Ibid

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