NASA's Fixer-Upper Flies Again

PATCH JOB NASA has developed five ways for astronauts to repair shuttle damage in orbit-although none will be fully ready in time for this month´s launch. Shown here: a simulation of STA-54, a kind of caulking, being spread over a damaged tile. John B. Carnett

The human thermal vacuum chamber at NASA's Johnson Space Center in Houston–the only facility of its kind in the world–looks like a prop from a Jules Verne movie. Picture a colossal metal drum surrounded by gargantuan pipes and fittings leaking fluid and spewing steam. By sucking air out of the chamber and running liquid nitrogen through the walls, engineers can lower the temperature to 140