The James Webb Space Telescope's combined Optical Telescope element/Integrated Science instrument module inside of Chamber A, a giant thermal vacuum chamber located at NASA’s Johnson Space Center in Houston, Texas. Inside the chamber, the telescope endures tests at sub-freezing cryogenic temperatures. The telescope will operate below an extremely cold 50 K (-223° C or -370° F) in space, so NASA is simulating those conditions on the ground, ensuring the optics and instruments will perform perfectly after launch. Credit: NASA/Chris Gunn #nasa #nasatech #techtuesday #jameswebb #telescope #houstontexas #spacecity