Dr. William (Bill) Farrell, Scientist, Lunar Exploration Program
- Created: Thursday, 01 May 2008
Goddard Space Flight Center, Greenbelt, MD
Dr. William Farrell, a scientist with the Lunar Exploration Program at Goddard Space Flight Center, is an expert on the problem of lunar dust and its effects on astronauts and equipment.
NASA Tech Briefs: What is lunar dust, and how does NASA currently deal with it?
Dr. Farrell: Lunar dust is usually particles that are less than 100 microns in size. However, the particles that the Exploration Program is really interested in are the grains that can possibly get into the lungs. Particles at about a few microns and below are of particular interest for the lunar crew in terms of human health since they can stick to air sacs in the lungs and destroy tissue. This illness is called silicosis and in acute forms it can be pretty serious.
NTB: Won’t the crew be completely encased in helmets and suits when they’re on the lunar surface?
Dr. Farrell: What we learned from Apollo is that they were donning their suits in the same atmosphere that they were breathing, so they were actually exposed to lunar dust, directly, right in that atmosphere. One of the big challenges that Constellation has is how to actually isolate the breathable air environment – the “short-sleeve” environment, if you will, that the astronauts are in – from the dust. There are ideas out there about using a suit-lock, or having some kind of airlock, but that kind of thing is really critical so that you get isolation from the dust.
NTB: When did NASA first learn about lunar dust and the problems it can cause?
Dr. Farrell: Well, actually the Apollo missions were the first clue that dust really could be an issue. Sandy Wagner at Johnson SFC put together a nice white paper on the impacts of dust on the various missions, and on some missions lunar dust was just reported to be present in the lunar module, but it was not a big issue. However, on other missions, particularly Apollo 16, lunar dust was everywhere and the astronauts really had a hard time. It created eye irritations, got in the nostrils, and because of those kinds of missions – the more extreme missions – NASA really started to appreciate just how invasive this dust can be. But it wasn’t every mission, so that’s kind of a curiosity as to why some missions didn’t experience a dust problem while others did.
NTB: One of the projects your group is working on is the development of a follow-on instrument to the Lunar Ejecta and Meteorites (LEAM) instrument developed by Otto Berg for Apollo 17. Please explain what that instrument was designed to do.