GREENBELT – In a massive “clean room” at the Goddard Space Flight Center, three people monitor a robotic arm as they simulate what would be a high-profile robotic servicing mission on the Hubble Space Telescope.
In a small basement room not far away, meanwhile, another set of workers quietly tests prototypes of mirrors planned for use on Hubble’s successor, the infrared James Webb Space Telescope.
Like the rooms where the two telescopes’ futures are being determined, Webb’s backers acknowledge that Hubble has center stage right now. It has captured the public’s imagination with dramatic photos of deep space, and talk of its demise has sparked a debate.
But they say Webb will be every bit as important scientifically — and should eventually gain center stage in the public’s mind.
“We’re pursuing an area of science that hasn’t been explored,” said John C. Mather, the senior project scientist for Webb. “I think we’ll make beautiful discoveries and beautiful pictures.”
Mather has worked on Webb since it was conceived in October 1995, when the National Aeronautics and Space Administration was trying to figure out what to do after Hubble and looking for what “next to discover.”
The answer to both was Webb. It is designed to observe the first light after the Big Bang — the theoretical beginning of the universe — as well as the first stars, galaxies and planets, which formed 1 million to a few billion years after the Big Bang.
“It extends our capabilities into an area in which we know almost nothing,” Mather said.
The telescope will also look for physical and chemical properties of early planetary systems in the hope of understanding how life originated and evolved.
“When you talk about structure and evolution of universe, it’s actually code for how we ended up here on Earth,” said Phil Sabelhaus, project manager for Webb.
Unlike Hubble, which records visible light, the 7-ton Webb telescope will look for infrared light — the wavelength of the oldest light in the universe, that closest to the Big Bang.
Scheduled for launch in August 2011, Webb will rely on a segmented primary mirror that, when opened, will be 6.5 meters across, making it comparable in power to a ground-based telescope. Those mirror sections are being tested now at Goddard.
Because good infrared observations can only be made in cold temperatures, Webb will be parked 1 million miles from Earth, where it will orbit the Sun, in Earth’s shadow. Once in space, Webb will be able to collect seven times as much data as Hubble, said Sabelhaus, who oversees a staff of a couple hundred.
“We’re pushing state of the art with the size of the telescope in particular,” he said. “The significant difference for us is being able to look further back in time than what you can do with Hubble or ground-based telescopes.”
Both Mather and Sabelhaus recognize Hubble’s achievements and both understand why people are fighting to keep it in the sky. But they also understand the reasons to cancel the last manned servicing mission to Hubble, which was dropped in the wake of the shuttle Columbia disaster.
Mather emphasized that there is no competition between Webb and Hubble — which could shut down by 2007 without another servicing mission or 2010 with one. He said the project team only hopes that the two space telescopes can be used, with ground-based telescopes, to complement each other.
“We designed the James Webb telescope not to compete with it (Hubble),” he said. “We said we’ll only do the things Hubble can never do, and similarly, we said we’d only do the things ground-based telescopes can never do.”
Still, Sabelhaus conceded that while Webb may prove scientifically important, its discoveries probably “won’t be on the front page of the New York Times” because they will be infrared images, not the visual images Hubble produces.
“People worry about the pretty picture to go along with the nice story,” Sabelhaus said, adding that NASA is working on ways to present Webb’s images like Hubble’s pictures.
In the meantime, Sabelhaus said NASA is committed to letting workers “prove out” all the technologies Webb will use in its scheduled five-year lifespan. That is all the more important since, with Webb 1 million miles away, there will be no opportunities for manned service, as there has been for Hubble.
“That gives us a lot more confidence in our ability to be able to build this telescope on budget and on schedule,” he said.
Webb is still a prototype, with actual construction not scheduled to begin until spring 2006, though work on the primary mirror segments will start later this year, Sabelhaus said.
He said preliminary costs for the telescope — which does not include operating costs — are estimated at $3 billion, with $2.5 billion in U.S. investment. The European Space Agency is providing some of the telescope’s instruments, and possibly the launch vehicle, Mather said.
But once Webb is launched, Mather said, if it is not embraced like Hubble “it would mean we were not explaining ourselves well.”
“I think we are going to have the discoveries that merit that kind of embrace,” he said. “It would be my fault if we can’t figure it out.”
-30- CNS 05-04-04