NASA’s “Chamber A,” an enormous thermal vacuum testing chamber housed at NASA’s Johnson Space Center in Houston, Texas, is now ready to conduct final optical testing on NASA’s James Webb Space Telescope (Webb telescope), the largest space observatory ever. A National Historic Landmark, Chamber A is famous for being used to test Apollo moon mission hardware, including suited astronauts inside the chamber on occasion. In order to test Webb prior to launch, the chamber had to undergo major upgrades in the last several years.