Twenty-Five-Foot Space Simulator


The Twenty-Five-Foot Space Simulator is a chamber designed for testing spacecraft in space-like conditions, including extreme cold, high radiation, and near-vacuum pressure. Built in 1961, it is located at the Jet Propulsion Laboratory in Pasadena, California, and has been used to prepare a large number of American space probes prior to their launches. It was declared a National Historic Landmark in 1985 and is on the National Register of Historic Places.

Description and history

The Twenty-Five-Foot Space Simulator is a stainless-steel cylinder in height and in diameter. A doorway wide and high provides access for bringing test objects and equipment into the chamber; a personnel access door is built into the larger doorway. The walls and floor of the chamber are lined with cooling shrouds providing a controllable temperature range from to. A series of lamps, lenses, and mirrors are capable of irradiating the chamber with a directed beam of simulated solar energy in a variety of patterns and strengths. The chamber is capable of being depressurized to 5×10−7 torr. Adjacent to the chamber is a clean room in which equipment can be prepared for testing.
Operation of the chamber requires about 75 minutes to achieve a space-like environment, and about 2-1/2 hours to return to a normal environment. The chamber is fitted with a number of attachment points and methods by which test objects can be mounted. The floor of the chamber is mounted on a seismically isolated foundation.
When the chamber was built in 1961, it was the only facility of its type. It was used to test the Ranger, Surveyor, Mariner, and Voyager spacecraft, and served as an example for other countries seeking to establish space programs.