Nope, it is not what you think. It is Chamber A NASA’s vacuum chamber. Chamber A can subject anything within its 400,000 cubic feet to
the deadly conditions of deep space while maintaining the
scrubbed conditions of a clean room. To give you a sense of scale, look at the two people standing in the door of the massive chamber. The door itself weighs in at 40-tons. Chamber A
can also reach 11 Kelvin, making it the coldest place on Earth.
The chamber was originally commisioned to test Apollo equipment in a space environment and was later refitted to test air bag landing systems used by some of the earlier Martian rovers.
Chamber A recently went through a refit for testing the James Webb Space Telescope.
Wikipedia listing Here
