Science & Technology
Thu August 15, 2013
Utah's Piece of the Webb Space Telescope Finished
For the past 11 years, ATK Space Systems has been working on its contribution to an advanced space telescope system. Its carbon fiber composite structure is shipping out next week for further testing – and it’ll eventually wind up a million miles out in space.
The James Webb Space Telescope is meant to replace the venerable Hubble Space Telescope as the most advanced astronomical system available to science.
Instead of one eight-foot mirror at the end of a tube, as in the Hubble, it will have eighteen hexagonal mirror segments, made of beryllium and coated with a thin layer of gold. They’ll function as a single unit 6.5 meters across, reflecting light into the telescope’s cameras and other instruments.
The James Webb telescope will use infrared light for its observations. University of Utah astronomy professor Adam Bolton says that will allow scientists to look back in time to the very earliest days of the universe. As the universe has expanded over billions of years, Bolton says the light from the earliest galaxies has been stretched to the point that it’s no longer visible in the spectrum we can see.
Bolton tells KUER, “All the features that we’re used to looking at and associating with images of galaxies, all the starlight that traces out spiral arms and the bulges in the centers of galaxies, that all gets shifted toward these infrared wavelengths. So if we don’t have infrared telescopes, we can’t actually look directly at those features in galaxies in the very young universe. And the Webb telescope will let us do that.”
Those observations will need a level of precision that’s never been achieved before on such a large structure – and certainly not in space. Program manager Bob Hellekson pointed to the black framework in ATK’s clean room in West Valley City.
“Our requirement was to hold that mirror to 38 nanometers, which is about 1/1,000th the thickness of a human hair," Hellekson says, "while the cameras are taking their images over about 14-day excursion.”
The assembly built at ATK is the backbone of the telescope. It looks a little like a bridge or a building structure, with carbon fiber tubes crossing and reinforcing each other. It’s about twenty feet long and eight feet wide, and it’s curved on one side to accommodate the parabolic shape of the mirrors. With the other components of the telescope, it’ll have to be folded into the cargo space of a French Ariane rocket for launch. It’ll unfold itself when it reaches the point in space called L-2, where the gravity of the earth and the sun are in balance – about a million miles from Earth.
The total price tag on the Webb space telescope project is about eight billion dollars. ATK’s Bob Hellekson says it’s been worth about 200-million dollars to his company, much of that supporting work here in Utah.
Hellekson talked about a meeting of ATK personnel at its facility in West Valley City. “Out of curiosity, I asked, ‘Of the 200 people here, how many had not been working on James Webb?.’ And I had, out of the 200, one hand go up. So, one way or the other, over the 11 years, virtually everybody at ATK here on this site has worked on this program.”
The graphite composite structure is being packed into a shipping container for the trip to the Marshall Space Flight Center in Huntsville, Alabama. There, it will undergo several more years of testing.
And when it’s in place, astronomer Adam Bolton says it could help to solve some of the biggest mysteries in astronomy – like the role of the dark matter that makes up most of the mass of the universe.
“We know that galaxies have to form within what we call ‘halos’ of dark matter," he explains. "But we can’t directly observe galaxies in those very earliest epics of formation, at least not in any great detail, with any of our current telescopes. And what the Webb telescope will let us do is take very high quality pictures of what are essentially baby galaxies which we think will be forming inside these very early dark matter concentrations.”
The Webb telescope structure is leaving ATK’s plant in West Valley on the 21st… and the whole system should be ready for launch in 2018.