The next generation of great space telescopes is heading into its final round of ground tests. The nearly $9 billion James Webb Space Telescope will replace the aging Hubble Space Telescope. It's designed to provide unprecedented images of the earliest stars and galaxies that formed in the universe.
But before the telescope can get to work, there are still a lot of engineering challenges to overcome.
For example, the Webb telescope is designed to look at the infrared wavelengths of light given off by stars. Infrared is needed to see some of the earliest stars and galaxies that formed billions of years ago.
But to work properly, infrared telescopes have to be kept cold — very cold. So engineers had to design a multilayered sun shield to protect the telescope from the sun's heat.
"That's like a big umbrella — beach umbrella — so, we keep that facing the sun and the Earth so it dissipates all the heat through all the layers," says Begoña Vila, an astrophysicist and systems engineer at NASA's Goddard Space Flight Center, in Greenbelt, Md. "That allows all the instruments to cool to the temperatures that we need."
Now, the sun shield is big, about the size of a tennis court, and for launch it has to fit into a much smaller space — about the size of a school bus. So engineers had to come up with a way to fold it up. They also had to design a way to fold up the main mirror, and several other critical instruments.
Then, after launch, everything has to unfold in a carefully choreographed sequence of steps over two weeks. You can see that sequence in this video.
Many of the steps are absolutely crucial. A failure would compromise the telescope's functionality and could render it useless. For the army of scientists and engineers who have been working on the telescope for nearly two decades, the deployment phase will be nerve-wracking.
"Yes, I think that scares all of us," says Vila. But there's no way around it. "We do as much testing as we can."
The Webb telescope has had a difficult history. It is over budget and behind schedule, and Congress nearly killed the project earlier in the decade. The telescope is scheduled to launch in October 2018. We should know later that year whether the engineering challenges were successfully cleared.
STEVE INSKEEP, HOST:
Now, the massive James Webb Space Telescope is heading into its final round of ground tests. The nearly $9 billion observatory will replace the aging Hubble Space Telescope, and astronomers are giddy about the wealth of new information they expect to gain if they get the telescope to work. NPR's Joe Palca reports.
JOE PALCA, BYLINE: A virtual army of scientists and engineers has been laboring to get the new telescope ready for launch. Astrophysicist and systems engineer Begona Vila is a relative newcomer on the project.
BEGONA VILA: Oh, only 10 years.
PALCA: Vila works at the Goddard Space Flight Center in Greenbelt, Md. It's here that the telescope's mirrors and instruments are frozen, shaken and rattled to make sure they'll survive their trip to a spot a million miles from Earth. Unlike Hubble, the James Webb telescope is primarily designed to look at the universe at what's called infrared wavelengths. This allows it to peer through dust clouds and to see how the earliest stars and galaxies formed. But to work properly, infrared telescopes have to be kept cold - very cold. Vila says the Webb telescope uses a multi-layered sunshield to protect it from the sun's heat.
VILA: That's like a big umbrella - beach umbrella - so we keep that facing the sun and the Earth so all the heat on it dissipates - all the heat through the layers. So that allows all the instruments to cool to the temperatures that we need.
PALCA: Now, the sunshield is big - about the size of a tennis court. And for launch, it has to fit into a much smaller space - about the size of a school bus. So the sunshield has to fold up, as does the large main mirror and a variety of other essential instruments. The unfolding takes place in a carefully choreographed sequence of steps over two weeks.
(SOUNDBITE OF MUSIC)
UNIDENTIFIED WOMAN #1: Solar panels extend.
ARI SHAPIRO, BYLINE: Antenna deployment.
DAVID GREENE, BYLINE: Forward sunshield panel deployment.
PALCA: Each step is critical. No solar panels, no power. No antenna, no communications. No forward sunshield, no cooling.
SHAPIRO: Aft sunshield panel deployment.
UNIDENTIFIED WOMAN #2: Aft membrane cover release
UNIDENTIFIED WOMAN #1: First sunshield mid-boom deployment.
PALCA: And finally, the two wings that hold the key parts of the telescope's main mirror have to unfold. If everything deploys as it should, the telescope is ready for business. But it's a lot of things that have to deploy just right. So I asked Begona Vila, doesn't that scare you?
VILA: Yes, I think it scares all of us.
PALCA: She says there's really no way around it.
VILA: We do as much testing as we can, as thorough a test as we can. And we also have multiple review teams that check results and make sure that we are not missing anything and that, you know, we are doing the best we can to confirm everything is going to work.
PALCA: Already way over its initial budget and behind schedule, the Webb telescope is supposed to launch in October 2018. We should know later that year whether all those tests and reviews missed anything crucial. Joe Palca, NPR News. Transcript provided by NPR, Copyright NPR.