The Space Environment Simulation Laboratory (SESL) in Building 32 at the Lyndon B. Johnson Space Center was built in 1965. It initially was used to test Apollo Program spacecraft and equipment in a space environment. It can simulate the vacuum and thermal environments that would be encountered. It consists of two human-rated chambers: A (larger) and B. Chamber A is equipped with a liquid helium shroud capable of reaching temperatures of -439.9 Fahrenheit (-262.1 Celsius or 11 Kelvin,) and is currently being used to test the James Webb Space Telescope.