Astronauts practice for working in space in NASA's Weightless Environment Training Facility (WETF), a large water tank that contains a mockup of the space shuttle orbiter payload bay and various payloads. The astronauts are assisted here by SCUBA equipped divers.

The 21st century promises the challenge for humans to live and work in space. The achievements of scientists, engineers, technicians, and specialists who will build and operate the Space Station are the legacy of the National Aeronautics and Space Administration's (NASA's) many years of experience in selecting and training astronauts to work on the frontier of space.