The suits are similar to those worn in space, except they don't last as long on Earth, says Louis Carfagno, spacesuit engineer for United Space Alliance, a private contractor that makes and maintains the spacesuits. Before sending them under, workers strap a tool belt and a tether onto each astronaut. The tether is used to latch onto the mock-up. Without something to latch onto, it's virtually impossible to work in a weightless environment. So the space station has more handrails and restraints than a nursing home.
Divers also take two big tool boxes into the water.
In all, more than 300 tools will go down for the four astronauts. It's an inside joke, referring to Wisoff and Lopez-Alegria's upcoming mission, scheduled for early October. Once in the water, the work begins for both astronaut teams. Maneuvering in such a weightless environment can be tricky. Even tiny movements can be exhausting.