YES IN THE SKY
ONE OF AMERICA’S LEAST KNOWN National Historic Landmarks may also be its ugliest. It’s kept hidden inside Building 32 on the grounds of the Johnson Space Center in Houston and is identified simply as Chamber A. The “landmark” resembles nothing so much as a bank vault, albeit one with a 40-ton, 40-ft.-wide door.
When the door is shut, however, and the right machinery is turned on, Chamber A becomes, effectively, a giant pocket of outer space. Pumps create a vacuum, and a liquid helium and nitrogen cooling system drives the temperature down to–440°F, not far from absolute zero, the thermal floor at which most molecular motion stops.
The chamber was built in 1965 and earned its landmark status both for its innovative design and for its work stress-testing the Apollo lunar spacecraft. Now, it’s preparing to inflict its punishment on the next great space machine to come its way: the James Webb Space Telescope.
On a recent afternoon, the main mirror and instrument package of the Webb—named after the NASA administrator who ran the agency in the early part of the Apollo era—sat in the filtered-air clean room outside the chamber, being prepped for a 93-day stay in simulated space. That test, which will begin in July, will be a very high-stakes exercise. The
