Moon Dust – rediscovered
Moon dust is in the news. The Lunar Atmosphere and Dust Environment Explorer (LADEE) mission currently in lunar orbitis about to begin the science phase of examining the thin lunar exosphere and looking for signs of dust fountains and the curious glow of lofted dust on the lunar horizon as reported by several Apollo astronauts.
It’s soft, sticky, scratchy stuff that has a tendency to cling to everything and was responsible for ruining several scientific experiments, causing them to overheat. A big challenge on each Apollo mission was to stop it getting it inside the lunar module. John Young (Apollo 16) thought it tasted “not half bad, ” Gene Cernan (Apollo 17) said it smelled like spent gunpowder and Jack Schmitt (Apollo 17) developed the first case of lunar moon dust “hay fever.”
Apollo missions 12, 14 and 15 left scientific experiments on the Moon (using solar cells) aimed at finding out how fast moon dust would accumulate. A build-up of moon dust blocked sunlight causing the voltage produced by the solar cells to drop. Shielded and unshielded tiny solar cells sent data back to Earth until 1977. NASA assumed the data had been lost until 40 years after the solar cells had been left on the Moon the lunar scientist who developed the experiment, Brian O’Brien, said he had backup copies and began to analyse the data.
The conclusion is that moon dust builds up faster than it should in a place with no atmosphere – just the thinnest of exospheres – at a rate of 1 millimetre every 1,000 years. Why? The strange dusty lunar exosphere holds the answer.
Over to LADEE.