Space isn't hard only on account of the rocket science. The task of taking a NASA mission from development and funding through construction and launch — all before we even use the thing for science — can span decades. Entire careers have been spent putting a single satellite into space. Nobel-winning NASA physicist John Mather, mind you, has already helped send up two.
In their new book, Inside the Star Factory: The Creation of the James Webb Space Telescope, NASA's Largest and Most Powerful Space Observatory, author Christopher Wanjek and photographer Chris Gunn take readers on a behind the scenes tour of the James Webb Space Telescope's own journey from inception to orbit. Weaving examinations of the radical imaging technology that enables us to peer deeper into the early universe than ever before with profiles of the researchers, advisors, managers, engineers and technicians that made it possible through three decades of effort. In this week's Hitting the Books excerpt, a look at JWST project scientist John Mather and his own improbable journey from rural New Jersey to NASA.
Excerpted from “Inside the Star Factory: The Creation of the James Webb Space Telescope, NASA's Largest and Most Powerful Space Observatory” Copyright © 2023 by Chris Gunn and Christopher Wanjek. Used with permission of the publisher, MIT Press.
John Mather, Project Scientist
— The steady hand in control
John Mather is a patient man. His 2006 Nobel Prize in Physics was thirty years in the making. That award, for unswerving evidence of the Big Bang, was based on a bus-sized machine called COBE — yet another NASA mission that almost didn’t happen. Design drama? Been there. Navigate unforeseen delays? Done that. For NASA to choose Mather as JWST Project Scientist was pure prescience.
Like Webb, COBE — the Cosmic Background Explorer — was to be a time machine to reveal a snapshot of the early universe. The target era was just 370,000 years after the Big Bang, when the universe was still a fog of elementary particles with no discernable structure. This is called the epoch of recombination, when the hot universe cooled to a point to allow protons to bind with electrons to form the very first atoms, mostly hydrogen with a sprinkling of helium and lithium. As the atoms formed, the fog lifted, and the universe became clear. Light broke through. That ancient light, from the Big Bang itself, is with us today as remnant microwave radiation called the cosmic microwave background.
Tall but never imposing, demanding but never mean, Mather is a study in contrasts. His childhood was spent just a mile from the Appalachian Trail in rural Sussex County, New Jersey, where his friends were consumed by earthly matters such as farm chores. Yet Mather, whose father was a specialist in animal husbandry and statistics, was more intrigued by science and math. At age six he grasped the concept of infinity when he filled up a page in his notebook with a very large number and realized he could go on forever. He loaded himself up with books from a mobile library that visited the farms every couple of weeks. His dad worked for Rutgers University Agriculture Experiment Station and had a laboratory on the farm with radioisotope equipment for studying metabolism and liquid nitrogen tanks with frozen bull semen. His dad also was one of the earliest users of computers in the area, circa 1960, maintaining milk production records of 10,000 cows on punched IBM cards. His mother, an elementary school teacher, was quite learned, as well, and fostered young John’s interest in science.
A chance for some warm, year-round weather ultimately brought Mather in 1968 to University of California, Berkeley, for graduate studies in physics. He would fall in with a crowd intrigued by the newly detected cosmic microwave background, discovered by accident in 1965 by radio astronomers Arno Penzias and Robert Wilson. His thesis advisor devised a balloon experiment to measure the spectrum, or color, of this radiation to see if it really came from the Big Bang. (It does.) The next obvious thing was to make a map of this light to see, as theory suggested, whether the temperature varied ever so slightly across the sky. And years later, that’s just what he and his COBE team found: anisotropy, an unequal distribution of energy. These micro-degree temperature fluctuations imply matter density fluctuations, sufficient to stop the expansion, at least locally. Through the influence of gravity, matter would pool into cosmic lakes to form stars and galaxies hundreds of millions of years later. In essence, Mather and his team captured a sonogram of the infant universe.
Yet the COBE mission, like Webb, was plagued with setbacks. Mather and the team proposed the mission concept (for a second time) in 1976. NASA accepted the proposal but, that year, declared that this satellite and most others from then on would be delivered to orbit by the Space Shuttle, which itself was still in development. History would reveal the foolishness of such a plan. Mather understood immediately. This wedded the design of COBE to the cargo bay of the unbuilt Shuttle. Engineers would need to meet precise mass and volume requirements of a vessel not yet flown. More troublesome, COBE required a polar orbit, difficult for the Space Shuttle to deliver. The COBE team was next saddled with budget cuts and compromises in COBE’s design as a result of cost overruns of another pioneering space science mission, the Infrared Astronomical Satellite, or IRAS. Still, the tedious work continued of designing instruments sensitive enough to detect variations of temperatures just a few degrees above absolute zero, about −270°C. From 1980 onward, Mather was consumed by the creation of COBE all day every day. The team needed to cut corners and make risky decisions to stay within budget. News came that COBE was to be launched on the Space Shuttle mission STS-82-B in 1988 from Vandenberg Air Force Base. All systems go.
Then the Space Shuttle Challenger exploded in 1986, killing all seven of its crew. NASA grounded Shuttle flights indefinitely. COBE, now locked to Shuttle specifications, couldn’t launch on just any other rocket system. COBE was too large for a Delta rocket at this point; ironically, Mather had the Delta in mind in his first sketch in 1974. The team looked to Europe for a launch vehicle, but this was hardly an option for NASA. Instead, the project managers led a redesign to shave off hundreds of pounds, to slim down to a 5,000-pound launch mass, with fuel, which would just make it within the limits of a Delta by a few pounds. Oh, and McDonnell Douglas had to build a Delta rocket from spare parts, having been forced to discontinue the series in favor of the Space Shuttle.
The team worked around the clock over the next two years. The final design challenge was ... wait for it ... a sunshield that now needed to be folded into the rocket and spring-released once in orbit, a novel approach. COBE got the greenlight to launch from Vandenberg Air Force Base in California, the originally desired site because it would provide easier access to a polar orbit compared to launching a Shuttle from Florida. Launch was set for November 1989. COBE was delivered several months before.
Then, on October 17, the California ground shook hard. A 6.9-magnitude earthquake struck Santa Cruz County, causing widespread damage to structures. Vandenberg, some 200 miles south, felt the jolt. As pure luck would have it, COBE was securely fastened only because two of the engineers minding it secured it that day before going off to get married. The instrument suffered no damage and launched successfully on November 18. More drama came with the high winds on launch day. Myriad worries followed in the first weeks of operation: the cryostat cooled too quickly; sunlight reflecting off of Antarctic ice played havoc with the power system; trapped electrons and protons in the Van Allen belts disrupted the functioning of the electronics; and so on.
All the delays, all the drama, faded into a distant memory for Mather as the results of the COBE experiment came in. Data would take four years to compile. But the results were mind-blowing. The first result came weeks after launch, when Mather showed the spectrum to the American Astronomical Society and received a standing ovation. The Big Bang was safe as a theory. Two years later, at an April 1992 meeting of the American Physical Society, the team showed their first map. Data matched theory perfectly. This was the afterglow of the Big Bang revealing the seeds that would grow into stars and galaxies. Physicist Stephen Hawking called it “the most important discovery of the century, if not of all time.”
Mather spoke humbly of the discovery at his Nobel acceptance speech in 2006, fully crediting his remarkable team and his colleague George Smoot, who shared the prize with him that year. But he didn’t downplay the achievement. He noted that he was thrilled with the now broader “recognition that our work was as important as people in the professional astronomy world have known for so long.”
Mather maintains that realism today. While concerned about delays, threats of cancellation, cost overruns, and not-too-subtle animosity in the broader science community over the “telescope that ate astronomy,” he didn’t let this consume him or his team. “There’s no point in trying to manage other people’s feelings,” he said. “Quite a lot of the community opinion is, ‘well, if it were my nickel, I’d spend it differently.’ But it isn’t their nickel; and the reason why we have the nickel in the first place is because NASA takes on incredibly great challenges. Congress approved of us taking on great challenges. And great challenges aren’t free. My feeling is that the only reason why we have an astronomy program at NASA for anyone to enjoy — or complain about — is that we do astonishingly difficult projects. We are pushing to the edge of what is possible.”
Webb isn’t just a little better than the Hubble Space Telescope, Mather added; it’s a hundred times more powerful. Yet his biggest worry through mission design was not the advanced astronomy instruments but rather the massive sunshield, which needed to unfold. All instruments and all the deployment mechanisms had redundancy engineered into them; there are two or more ways to make them work if the primary method fails. But that’s not the only issue with a sunshield. It would either work or not work.
Now Mather can focus completely on the science to be had. He expects surprises; he’d be surprised if there were no surprises. “Just about everything in astronomy comes as a surprise,” he said. “When you have new equipment, you will get a surprise.” His hunch is that Webb might reveal something weird about the early universe, perhaps an abundance of short-lived objects never before seen that say something about dark energy, the mysterious force that seems to be accelerating the expansion of the universe, or the equally mysterious dark matter. He also can’t wait until Webb turns its cameras to Alpha Centauri, the closest star system to Earth. What if there’s a planet there suitable for life? Webb should have the sensitivity to detect molecules in its atmosphere, if present.
“That would be cool,” Mather said. Hints of life from the closest star system? Yes, cool, indeed.
This article originally appeared on Engadget at https://ift.tt/6ewhqsmfrom Engadget is a web magazine with obsessive daily coverage of everything new in gadgets and consumer electronics https://ift.tt/6ewhqsm
No comments:
Post a Comment
Guys Comments for Revolutionary Change!!!