Looking in the Sky for Evidence of the Big Bang


Charles L. Bennett stood in the cold, pre-dawn morning at Vandenberg Air Force Base in California and fixed his eye on an aging NASA rocket -- a patch here, a bit of glue there. The rocket was a Delta-1, the last remaining booster in an early series of expendable rockets that had sent a host of highly successful scientific payloads into orbit.

It was Nov. 18, 1989, and the National Aeronautics and Space Administration was about to launch one of the most complex satellites ever built, a 2 1/2 -ton package of delicate instruments designed to help answer such basic questions as how the universe evolved after a primordial Big Bang which scientists believe occurred about 15 billion years ago.

However, on this November morning, Dr. Bennett, who earned his Ph.D. in radio astronomy at the Massachusetts Institute of Technology, was not in a mood for big-picture reflection. He was thinking of the more-precious-than-gold satellite, the product of 1,600 man years of work at NASA's Goddard Space Flight Center in Greenbelt.

Such moments typify the behind-the-scenes anxiety that the public rarely sees but is always there when a rocket lifts from the planet or technicians send a radio command to a satellite millions of miles from Earth. Everything has to work, and "second best" is never good enough.

So, this was the ninth inning in the seventh game of the World Series for the Goddard people, and Dr. Bennett was painfully aware that rockets, even the dependable Delta family of boosters, shake, rattle and roll as their engines propel their payloads to orbital altitudes.

"I can't describe the feeling," he said, recalling the cold morning at Vandenberg. "All the years of work could go up in an instant" if anything went wrong.

His mind was totally focused on the satellite, named the Cosmic Background Explorer (COBE), designed and built -- oh, so carefully -- by the scientists, engineers and technicians at Goddard.

"Don't do that, you'll break it," Dr. Bennett recalled saying to himself, laughing now at the absurdity of the thought as the launching crew prepared to fire the Delta.

The satellite didn't break. The aging Delta worked perfectly.

"Best Delta launch I've ever seen," said John L. Wolfgang, a veteran electrical engineer on the Goddard team that put COBE together.

Soon, the instruments aboard COBE (pronounced COH-bee) were radioing back to Earth the initial data about the early times and anatomy of the universe.

One of the instruments detected extremely faint temperature fluctuations in the sky, which proved to be the long-sought variations scientists suspected were to be found in what may be called the "afterglow" of the Big Bang. This discovery, announced last year by Dr. George F. Smoot of the University of California at Berkeley, was something like finding a key missing page in an otherwise engrossing mystery novel.

Then, on Jan. 8 of this year, the Goddard scientific team headed by Dr. John C. Mather, told a meeting of the American Astronomical Society in Phoenix that another instrument aboard the COBE had detected further, convincing evidence that almost all of the early radiant energy of the universe (heat, visible light, radio waves, etc.) was released within the first year of the Big Bang. This disclosure lent further weight to the legitimacy of the Big Bang theory.

"The Big Bang theory comes out a winner," Dr. Mather said. "This is the ultimate goal in tracing one's roots."

It had been a long road for everyone connected with the project.

The concept of the instrumented COBE spacecraft began 19 years ago with Dr. Mather, who received his Ph.D. from Berkeley. In 1974, as a post-doctoral student, he put together a proposal for a satellite of several instruments that would do the work that COBE is now doing.

"He is the father of COBE," said Dr. Nancy W. Boggess, another key member of the Goddard group that worked on the project.

"If I am the father, she is the mother," Dr. Mather replied with a smile when told of Dr. Boggess' comment. "She backed us very strongly."

Dr. Boggess, who earned her doctorate in astrophysics at the University of Michigan in Ann Arbor, chaired the peer review group that evaluated and approved the Mather proposal and lobbied for the project at the NASA management level.

"To me, it [the Mather proposal] was the grandest thing I could imagine." she said.

The COBE people needed all the backing they could get.

After receiving initial approval for the project from NASA headquarters in Washington, the scientists at first thought in terms of building a satellite that would fly on an expendable rocket, such as the Delta.

Then the headquarters people decided to fly as many satellites as possible on the space shuttles which were coming into general use in the early 1980s. The powerful shuttles can carry a much heavier payload in their cargo bays than is possible on the Delta.

So, the Goddard scientists and engineers changed plans and put together a larger, 5-ton satellite. It was ready to go aloft in 1986 when the Challenger accident happened at Cape Canaveral, Fla., taking the lives of all seven astronauts aboard the shuttle.

The remaining shuttles were grounded while the Government launched an intensive investigation of the tragedy.

"We were literally bolting the spacecraft together when the Challenger accident came," Mr. Wolfgang said.

Again, the design of the spacecraft had to be changed.

For the COBE team it was "back to the drawing board," Dr. Bennett said. "It took 2 1/2 years. "For the complex task at hand, 2 1/2 years was like running a 3 1/2 -minute mile," he explained. "It was very fast work."

"We promised [headquarters in Washington] that we could do it fast. A lot of people worked long and hard to make it happen."

The Goddard scientists and engineers formed a "tiger team" of 200 people to work round the clock on the necessary changes. They redesigned the craft, reducing its weight by half, shrinking its diameter from 15 feet to 12 feet and making other changes to adapt COBE to the Delta's performance capabilities.

All the while they had to preserve the integrity of the delicate instruments.

"This team of 200 -- in a year they probably did five years work," said Mr. Wolfgang, who holds three degrees in engineering from George Washington University.

"No program I have been connected with ever had so many obstacles," Dr. Allan Sherman, Goddard's deputy director of engineering, said.

"We underestimated the job when we started out," said Dr. Sherman, who received his Ph.D. in engineering from the University of Maryland College Park. "We truly underestimated the challenge.

"The instruments were . . . one headache after another," he added.

One major problem was associated with the "thermos bottle" aboard COBE. This container held super-cooled liquid helium which had to be kept at a temperature of minus 457 degrees Fahrenheit to enable it to detect the sky's slight fluctuations in temperature that came from the afterglow of the Big Bang.

"The technology didn't exist for this low-temperature stuff, and we really had to develop a lot of it," Dr. Sherman said.

For example, Dr. Mather pointed out, at these very low temperatures -- close to the point where all molecular motion ceases -- glue won't always stick and materials can become frustratingly brittle. In addition, the liquid helium is prone to leak through the tiniest cracks imaginable.

The "low temperature stuff" goes by the name of cryogenics and, in the case of one instrument, meant keeping the instrument cold enough to recognize or record the very low cosmic temperatures the scientists were looking for.

Fundamental to the success of the COBE project, in Dr. Mather's view, was the interplay of ideas among the scientists, engineers and technicians at Goddard. The scientists were not off in one corner, the engineers in another and the technicians somewhere else. Suggestions were welcomed from anyone who came forward with a plausible solution to a particular problem.

"I think that [interplay among people] was one of the keys to the success of this project," Dr. Mather said.

But there were other personnel problems.

The senior people at Goddard were faced with a NASA hiring freeze during much of COBE's development, which meant that there was a shortage of experienced engineers while work was in progress. Consequently, the old hands had to break in young engineers who had never tackled anything as complex as COBE in their university training.

In the long run, this problem turned into a bonus which would provide the Goddard Space Flight Center with a cadre of newly (( trained young professionals to work on future projects.

"We trained a generation of engineers," Dr. Sherman said.

The first fruits of these years of hard work are now coming to public attention and the satisfaction and joy at Goddard are hard miss.

Summing up the whole COBE project, Dr. Boggess put it this way: "We have done something important that will be a legacy for all future scientists."

In addition, the Goddard experience with COBE reiterates the sometimes forgotten fact that success on the leading edge of high-tech science and engineering is never a sure thing and always hard work.

Albert Sehlstedt, a retired science writer for The Sun, has

covered the space program since its inception.

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