Space Environment Simulation Laboratory

Chamber A is the larger of the two chambers. It has a diameter of 45 feet (14 m), with a circular floor that can be rotated 180°. Test subject equipment can be maneuvered using four overhead cranes, each with a carrying capacity of 50,000 pounds. Equipment can be lifted into and out of the chamber using 100,000 pound cranes located outside the chamber. In addition to solar lighting arrays, the facility is capable of generating thermal plasma fields of a type experienced in the outer atmosphere and low Earth orbit. There are two man-sized airlocks, one at ground level, and one at 31 feet (9.4 m). These chambers are used for staging safety personnel during testing involving humans, and can be separately used for small-scale altitude tests involving low air pressures.[3]

NASA remodeled and upgraded the chamber to test the James Webb Space Telescope. As of 2013, it is the largest high-vacuum, cryogenic-optical test chamber in the world, 55 feet (17 m) in diameter by 90 feet (27 m) tall. It is equipped with a gaseous helium shroud capable of lowering temperatures to 11 K (−439.9 °F; −262.1 °C). Additional test support equipment includes mass spectrometers, infrared cameras and television cameras were installed to monitor testing.[4]

Chamber B is smaller, with a diameter of 20 feet (6.1 m), and is served by two 100,000 pound cranes. Like Chamber A, it has two airlocks; one of them is configured to a water deluge system and other elements needed to simulate oxygen-rich environments encountered on spacecraft. Its solar lighting array is also simpler than that of Chamber A, necessating the use of mirrors to achieve certain lighting angles. The smaller size of the chamber makes it possible to more efficiently perform tests on smaller objects with a more rapid turnaround time.[3]