We tend to think of the moon as little more than a barren rock, but it’s very, very dusty. However, this dust is a little different than the stuff that collects on our bookshelves. Every time an Apollo astronaut walked off the moon and into his spacecraft, he tracked a load of dust with him. Breathing dust in, as Harrison Schmitt reported during Apollo 17 in 1972, caused sneezing and allergies like "lunar dust hay fever."
A NASA study in 2005 noted the particles damaged instrument covers, spacecraft radiators and spacesuit seals and "generally coated everything with surprising tenacity." The floating, sticky dust, technically known as lunar regolith, also made it tough to see during landing or during surface activities; for example, the Apollo 11 astronauts in 1969 repeatedly tripped over an external TV cable obscured in powder.
