The Zero Gravity Research Facility at the NASA Glenn Research Center in Cleveland, Ohio is a unique facility designed to perform tests in a reduced gravity environment. It has successfully supported research for the United States manned spacecraft programs and numerous unmanned projects. The facility uses vertical drop tests in a vacuum chamber to investigate the behavior of components, systems, liquids, gases, and combustion in such circumstances.
The facility consists of a concrete-lined shaft, 28 feet (8.5 m) in diameter, that extends 510 feet (160 m) below ground level. A steel vacuum chamber, 20 feet (6.1 m) in diameter and 470 feet (140 m) high, is contained within the concrete shaft. The pressure in this vacuum chamber is reduced to 13.3 newtons per square meter (1.3×10−4atm) before use.
The service building at the top of the shaft contains a shop area, control room, and a clean room. Assembly, servicing, and balancing of the experiment vehicle are accomplished in the shop area. Tests are conducted from the control room, which contains controls for the "pump down" of the vacuum chamber, the experiment vehicle pre-drop checkout, release and the data retrieval system.