CAPE CANAVERAL, Fla. (May 14) - For deuterium, a form of the simplest element, hydrogen, it's been all downhill since the big bang birth of the universe more than 10 billion years ago.

That's because all the deuterium in the cosmos was manufactured during history's first few minutes, before the density and pressure of the early universe fell below the threshold needed to cook up elements heavier than helium and lithium.

Since then, the total stock of deuterium, with a nucleus of one proton and one neutron, has been decreasing as the isotope is consumed by the nuclear furnaces in successive generations of stars.

But the details of deuterium's decline and fall across the expanding universe are not well understood. If scientists could get a handle on how fast the isotope is disappearing they could work backwards to pin down how much deuterium was present in the primordial universe.

And that would shed light on the inner workings of the big bang itself. "We think deuterium is a cosmic fossil left over from the big bang and it can only be destroyed in stars," said Warren Moos, a professor of physics and astronomy at Johns Hopkins University. "We want to understand that destruction process better and we can do that by studying the ratio of D to H [deuterium to hydrogen] in our galaxy.

"This is all part of a larger problem, which is to figure out the primordial value of D to H and from that, we can figure out the density of ordinary matter ... about three minutes into the big bang."

Moos is the principal investigator and man in charge of NASA's $200 million Far Ultraviolet Spectroscopic Explorer, known as FUSE for short.

Once the target of cost-cutting NASA budgeteers, the born-again astronomy satellite, the most complex space mission ever designed, built and operated by a university, is scheduled for launch next month from the Cape Canaveral Air Station atop a Boeing Delta 2 rocket.

"This is a big deal for a university, for Johns Hopkins, to be responsible for an entire satellite, the ground station and data archiving," said project manager Dennis McCarthy, a former NASA manager.

"We've had the opportunity to think a lot differently than the way I used to have to do it on the government side," he said. "And it's turned out real well. It's been done for a lot less cost and a lot quicker."

Along with studying the mechanisms of deuterium's destruction, FUSE also will focus on the galactic circulatory system, the way heavier elements forged inside stars and blown into space by supernova explosions are distributed to form new stars or planets. Even life itself.

"We will learn a lot about circulation and mixing of chemicals in galaxies and in the star-forming process," William Blair, a Johns Hopkins research scientist, wrote in a web-site description of the project.

"Are there great galactic fountains constantly cycling material through supernovae explosions and stellar winds, bursting out of the plane of their galaxies, squirting up into haloes, cooling and falling back into the mix?" he continued. "At some level, it must be happening. But we hope to quantify it in a way that has never been done before."

To do so, FUSE will use a sensitive spectrograph to record subtle changes in short-wavelength ultraviolet light emitted from bright quasars and other background sources as it passes through clouds of interstellar or intergalactic gas on the way to Earth.

Ultraviolet light from deep space generally is blocked by Earth's atmosphere and while spacecraft like the Hubble Space Telescope can study certain limited UV emissions, FUSE is by far the most sensitive such spacecraft ever built.

"These questions have been around for a long, long time," said project scientist George Sonneborn. "They've sort of been sitting on the back burner because there just wasn't an easy way to do it."

But now, with FUSE scheduled for launch around June 18, "the excitement is really, really palpable," he said, "not just with people connected with a few science teams but out in the [astronomical] community."

NASA initially approved the mission as an in-house project in 1986 and began funding development in 1989 based on a proposal from Moos and his co-workers for a sophisticated shuttle-launched spacecraft that would cost nearly $300 million to develop.

But as NASA struggled to recover from the 1986 Challenger disaster, the money available for such missions began to dry up. In 1994, Moos and McCarthy received a phone call from NASA managers saying the project was going to be terminated unless a more affordable alternative could be developed.

"I was encouraged to think about whether there was some part of that FUSE science that we could save," Moos reflected. "By the end of the week, we went in and suggested to NASA that we could save the core science but that required a change in the way it was done."

That change, he said, was that one institution - Johns Hopkins - "had to take complete control of the program."

"They gave us to the end of the calendar year to go out and do a study and see whether or not we could put together a credible mission the science community would buy into and we could, in fact, accomplish," he said.

What they came up with may serve as a roadmap for future so-called PI-class missions, that is, missions designed, managed and operated for NASA by the principal investigator and his or her organization.

Instead of developing new technology in the long-standing NASA tradition, the Johns Hopkins team decided to go with off-the-shelf hardware and software whenever possible and to buy an existing spacecraft design from Orbital Sciences Corp.

An autonomous ground station was set up at the University of Puerto Rico using a 15-foot antenna atop an old Department of Energy building. Commands to the satellite and downlinked data will flow over ISDN telephone lines to a control center in the Bloomberg Center for Physics and Astronomy at Johns Hopkins.

The only area where new technology was pursued was in development of the spectrographic detector.

At the heart of the instrument are four mirrors, two coated with silicon carbide to enhance reflectivity of the shortest UV wavelengths, and two coated with aluminum and lithium fluoride, optimized for longer wavelengths.

Incoming light strikes the mirrors and is reflected to four curved French-built gratings that act like prisms to break the light up into its component wavelengths. The spectral data is analyzed by two photon-counting detectors and stored on a digital recorder for transmission to the ground.

Operating in a circular 480-mile orbit tilted 25 degrees to the equator, FUSE will pass over the Mayaguez, Puerto Rico, ground station six to eight orbits in a row. It then will be out of contact for 10 to 11 hours, operating on its own, observing fresh targets and recording data.

Moos said the Johns Hopkins approach was successful in large part because it integrated science and engineering management from the ground up.

"Typically in large projects, the scientists set up a set of requirements ... and they sort of throw it over the wall," he said. "The engineers say 'yes sir' and they go off and they try to do it.

"Sometimes they misinterpret what the scientists want or the scientists don't realize that what they're asking for is a little crazy," Moos said. "So you have to open up that dialogue. ... This helped us enormously."

And so, instead of spending $300 million on the satellite, Johns Hopkins was able to build a spacecraft that will accomplish 70 percent of the original mission's objectives while costing NASA between $115 million and $120 million.

The Delta launch vehicle will run $40 million or so and another $40 million will be spent over the three-year design life to operate the vehicle and analyze the anticipated flood of data.

Moos said university management of complex programs like FUSE is not for everyone and that academic institutions should approach such projects with caution.

"You've got to think through what you're trying to do in a given program," he said. "If you're going to optimize the science, then this PI-class mission is the way to go. There may be other situations in which it doesn't make sense at all. Very large missions, I don't think single organizations have the resources [to support]."

William Harwood     *  CBS News
Aerospace Writer    *  The Washington Post
Cape Canaveral, FL  *  Space News

Web Site            *  www.cbs.com/network/news/space/

Return to the FUSE Press Materials page, or Return to the FUSE home page.