You’re looking at the James Webb Space Telescope as it’s lowered into NASA’s Goddard Thermal Vacuum Chamber. Inside the dark cavern, it is subjected to the same hostile environments as it will experience in space.
How do they do that? Well, the 12m tall, 8m diameter cylindrical chamber is evacuated of air using vacuum pumps, then uses liquid nitrogen and even colder liquid helium to drop the temperature. It gets down to -233C, or 40 degrees Kelvin. Which is pretty cold!
Fortunately, the James Webb Space Telescope, 116 days after it was first placed into the chamber, is now out. And, mercifully, still working. [NASA]
