Prior to its launch in April 1990, the Hubble Space Telescope (HST) went through years of development and testing. The HST was the first of its kind and the scientific community could only imagine the fruits of their collective labors. However, prior to its launch, more practical procedures, such as astronaut training, had to be developed. As the HST was to remain in orbit for years, it became apparent that on-orbit maintenance routines would have to be developed. The best facility to develop these maintenance practices was at the Neutral Buoyancy Simulator (NBS) at the Marshall Space Flight Center (MSFC). The NBS provided mock-ups of the HST (in sections), a Remote Manipulator System (RMS), and a shuttle's cargo bay pallet. This real life scenario provided scientists, engineers, and astronauts a practical environment to work out any problems with a plarned on-orbit maintenance mission. Pictured are two astronauts training at MSFC's NBS. One astronaut is using a foot restraint system attached to the RMS, while the other astronaut performs maintenance techniques while attached to the surface of the HST mock-up.