Lunar Dust

The Floating Lunar Dust

Moon doesn’t have an atmosphere synonymous to earth, so the surface of the satellite of earth mostly covered by a loose layer of heterogeneous superficial material covering solid rock called as regolith. The substance is a fine powder like, the tiny grains are most sharp and cut like glass, has a shiny look and nearly clings to everything. The dust formation occurs when meteoroids crash on the moon’s surface, heating and pulverizing the rocks and dirt, as a result the dust mixes with silica and other metals such as iron, tungsten etc. As solar wind and ultraviolet radiation preferentially occur in the moon surface due to the non-existence of atmosphere thus the radioactive rays charge the metals in the surface. Thus the charged ions produced in the process is called a plasma sheath in which dust particles levitate or float as if it defies gravity. According to the fountain model proposed in 2005 by the Laboratory for Extraterrestrial Physics at National Aeronautics and Space Administration (NASA) Goddard Space Flight Center, claimed that the float of the dust particle occurred due to electrostatic levitation. On the daylit side of the Moon, solar ultraviolet and X-ray radiation is energetic enough to knock electrons out of atoms and molecules in the lunar soil. Positive charges build up until the tiniest particles of lunar dust (measuring 1 micrometer and smaller) are repelled from the surface and lofted anywhere from meters to kilometers high, with the smallest particles reaching the highest altitudes. The particles fall down when the process gets repeated. During the night time, the dust gets negatively charged by electrons in the solar wind and attains higher velocity to get lifted to higher altitudes.

Lunar Dust
A laboratory experiment carried out by NASA team that explains why dust “levitates” on the moon. (Credit: NASA)

The study also reported some of the harmful effects of the dust found on the lunar surface on the manned outposts. This included, darkening of surfaces, leading to a considerable increase in radiative heat transfer, Effect tremendously on the coatings used on gaskets to seal equipment from space, optical lenses, solar panels, and windows as well as wiring, The detectors get tremendously heated due to the charged dust contamination on its surface, Possible damage to an astronaut’s lungs, nervous, and cardiovascular systems.

So it can be predicted that, if a day comes when humans colonize the Moon, this dust will be a significant challenge, as predicted by Penny King of the Australian National University (ANU) in Canberra. She further explains that It gets into everything, from astronauts’ suits to machinery and equipment, where it causes damage, she says. “Understanding how it moves around is pretty critical.”

The Indian space programme by Indian Space Research Organisation (ISRO) is gearing up for launching the Chandrayaan-2 orbiter and lander in March 2018. The mission will carry a first of its kind instrument, called the Radio Anatomy of Moon Bound Hypersensitive ionosphere and Atmosphere (RAMBHA), to measure the density of the near-surface plasma and perform further research to know the changes over time. The mission “is expected to further consolidate the findings from the first mission and add new ones with in-situ analysis of the lunar surface and ionosphere,” says Mylswamy Annadurai, who is also director of ISRO’s Satellite Centre in Bangalore.

Sources: NASA Goddard Space Flight Center, Wikipedia, NewYorker, Nature news

A research patron working in the field of Plasma and Nuclear Science. He prefers the hobby in writing scientific prologs and keeps a strong feeling in mind to promote knowledge by holding technology in hand.