When human explorers reach the Moon or Mars, they're going to have to watch out for something we've all experienced here on Earth: static electricity. Zap! It's annoying when you grab a door handle after rubbing your socks across the carpet. But the dry environments on the Moon and Mars could cause astronauts to build up a significant charge that could fry electronic equipment when they try to handle it. Astronauts may have to walk across a sheet of aluminum mesh to ground themselves before returning to base.