Massive Space Telescope Is Finally Coming Together

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. NPR can't go inside for risk of contamination, but I meet crew chief Dave Sime at an observation deck where we can see the mirror below. Simm works for the contractor Harris Corp., and he's normally in there assembling it. When he is, he has to wear a white suit that covers every inch of his body.

"The only thing exposed is your eyes," he says. (Spacecraft assembly pro tip, he adds: To use your cellphone in the clean area, try a Bluetooth headset under your protective clothing.)

For months now, he's been working 10-hour shifts. His job is to take 18 hexagonal mirror segments, each about the size of a coffee table, and attach them to the telescope's cobweb frame using glue and screws.

When everything is done, the mirror will look like a giant, golden satellite dish, two stories high.

The assembly process is precise, and more difficult than even an Ikea wardrobe. Sime points to a table covered in books filled with instructions: "Each one of those notebooks is for one mirror," he says.

Everything has to be by the book. The Webb telescope will be one of the most expensive things NASA has ever built. Its segmented mirror is so big that, once it's in space, it will have to unfold like an elaborate piece of origami. And to make observations, it will need to be a million miles from Earth, so far that no astronauts could fix it if it breaks.

But the Webb will be able to do things no other telescope can. It is designed to capture light from the first stars and galaxies, which has been traveling billions of years across the universe to reach our solar system. It will probe the atmospheres of potentially habitable planets outside the solar system. Astronomer John Mather is the telescope's project scientist at NASA, and he is pretty sure it's going to do other things too:

"Every time we build bigger or better pieces of equipment, we find something astonishing," he says.

The Webb is currently scheduled for launch in 2018.