This week, NASA is set to reach a milestone on one of its most ambitious projects. If all goes to plan, workers will finish assembling the huge mirror of the James Webb Space Telescope— an $8 billion successor to the famous Hubble telescope.
"So far, everything — knock on wood — is going quite well," says Bill Ochs, the telescope's project manager at Goddard Space Flight Center in Maryland.
The massive mirror is being built in a facility that's essentially a giant, ultra-clean gymnasium.