The James Webb Space Telescope is ready to launch

A half century in astronomy has earned Garth Illingworth a front-row seat to several rocket launches bearing his fingerprints. But he’s particularly ardent about the one coming up on December 24. That’s when the James Webb Space Telescope (JWST) blasts off from Guiana Space Centre in Kourou, French Guiana, to an orbit 1 million miles away, where it will glimpse the infant universe.

At $9.7 billion, the four-story, 14,000-pound space observatory is NASA’s most ambitious science mission yet, and among its most expensive. Its primary job is to capture and analyze traces of infrared light from the formation of the first stars and galaxies 13.5 billion years ago, some 200 million years after the Big Bang. But its four onboard instruments will also examine the atmospheres of rocky exoplanets orbiting nearby stars to determine their suitability for life, as well as the makeup of our solar system’s outer planets.

The JWST is an astonishing feat of engineering that has engaged thousands of scientists and engineers from 24 countries in academia, industry, and three space agencies: NASA, the Canadian Space Agency, and the European Space Agency. But considering the myriad obstacles assailing its 35-year crawl toward the finish line—technological mishaps, political infighting, ballooning budgets, near-cancellation, and a pandemic—its greatest achievement might be that it happened at all.

Few participants are more invested than Illingworth, a jovial Australian-born cosmologist who, at 74, holds the rarefied mantle of being the last of the telescope’s three original architects still involved with the mission. A professor emeritus of astronomy at the University of California, Santa Cruz, and a longtime NASA and Congressional science adviser, he will use the telescope next summer to research early galaxies.

“It’s amazing to finally be here, and a little nerve-racking, because of the huge effort and investment. A lot still has to happen,” he says. “But then there’s the excitement about the new worlds and discoveries just way beyond what we can even conceive.”

Garth Illingworth [Photo: courtesy of Garth Illingworth/NASA]

Come Friday, he’ll be viewing liftoff from the JWST Science and Mission Operations Center at the Space Telescope Science Institute (STScI) in Baltimore rather than on-site. “The launch is over in a few minutes,” Illingworth says. “But Mission Control will be where the action is for the crucial early deployments.”

Those involve an unprecedented mechanical ballet that’s been dubbed the 30 Days of Terror. A half hour after launch, the assemblage will emerge from the 16-foot diameter Ariane 5 rocket fairing to slowly unfurl during its monthlong nail-biting journey to the L2 (second Lagrangian point) orbit. There, combined Earth and sun gravitational forces will enable the observatory to move with the Earth about the sun while pointing its mirror outward to view the universe. Within 24 hours, the spacecraft will open a solar array to power deployment (plus the next decade or more of science operations), fire thrusters to course-correct, and erect an antenna to communicate with Earth.

Subsequent weeks will see it lift the telescope and instruments, open five silver sunshields to cool the craft, merge 18 hexagonal gold segments into a giant primary mirror, and extend an arm holding the secondary mirror. From there, teams will calibrate the telescope for use by July.

“Deployment is awfully complicated,” notes Illingworth in wry understatement.

In the beginning

In 1986, the Hubble Space Telescope, NASA’s Earth-orbiting ultraviolet (UV), visual, and near-infrared light observatory, was still four years from launch when Riccardo Giacconi, an experienced satellite designer serving as STScI’s visionary first director, called deputy director Illingworth to his office. If astronomy research were to continue its post-Hubble momentum, he argued, they would need to begin developing an even more powerful telescope immediately. Illingworth resisted. Not only did the Hubble need significant work, but NASA was reeling from the recent Space Shuttle Challenger explosion, which muddied future funding.

More significantly, the technology to realize Giacconi’s vision had yet to be invented or adapted to a large spacecraft. The finalized JWST is 100 times more powerful than the Hubble. Its 21.4-foot-diameter mirror is three times larger, yet a tenth lighter, to see more distant objects through longer mid-infrared wavelengths. Five 70-foot insulating sunshields and a mechanical refrigerator will cool the telescope and instruments to between minus 388 degrees and minus 448 degrees Farenheit to prevent the craft’s ambient heat from interfering with radiation from the early universe. The observatory will orbit far enough from the Earth and moon to avoid their reflected light. This entire structure folds into a rocket fuselage and autonomously unfurls in space.

[Animation: NASA’s Goddard Space Flight Center]

None of these hurdles seemed to bother Giacconi, a commanding Italian prone to dramatic flair, who would go on to win the 2002 Nobel in physics. Illingworth, in turn, pulled in chief engineer Pierre-Yves Bely, an imaginative engineer from France, and division head Hervey “Peter” Stockman, an astronomer he’d recently worked with at Kitt Peak National Observatory in Tucson, Arizona.

“We thought he was crazy,” laughs Illingworth of Giacconi’s proposal. “Not only did most of the technologies to achieve this not exist, but we didn’t even have a way of getting it there. He just dropped a bomb and then let the three of us figure it out.”

Riccardo Giacconi (second from left), Garth Illingworth (sixth from left), Peter Stockman (seventh from left), 1987 [Photo: courtesy of Garth Illingworth]

And so, in addition to their day jobs on the Hubble, the trio began a side gig conjuring the Next Generation Space Telescope (NGST), its initial moniker before getting its official name—honoring James E. Webb, NASA’s administrator from 1961 to 1968—in 2002. Bely’s telescope design background had him researching a game-changing approach of using sunshields to passively cool large-scale telescopes to lower temperatures. Stockman brought a keen understanding of telescope instruments. The three brainstormed concepts on imaging, thermal dynamics, and orbital maneuvers over coffee in the STScI cafeteria and at one another’s computers, sketching rudimentary designs on the half-hour drives to meetings at NASA Goddard Space Flight Center in Greenbelt, Maryland. “Both of the guys were very friendly and easy to interact with,” Illingworth says.

Pierre-Yves Bely in his office at NASA’s Goddard Space Flight Center [Photo: courtesy of Garth Illingworth]

“Those were exciting days,” adds Bely, now 84. “Such a large telescope, covering a wide spectral range and located beyond the moon, had never been constructed before.”

Over time, a small group of talented engineers joined their efforts, and ideas came and went—among them rigid sunshields, UV viewing capabilities, and a 52-foot moon-based version to appease a proposed lunar initiative at the time. A major astronomy conference and well-received concept presentations in 1989 and 1990 put the NGST on NASA’s map. But the subsequent recession of the early ’90s, the scramble to fix the Hubble’s botched optics post-launch, and a presidential administration change slowed its progress.

Even when NASA showed renewed interest in 1996, it designated a paltry $500 million to develop the telescope for an anticipated 2007 launch. It was a gross underestimation that would come back to haunt the project, as cost overruns and construction delays threatened to shut it down in 2011 and 2019.

One of Pierre-Yves Bely’s early telescope sketches [Image: courtesy of Pierre Bely]

“I always knew it would cost more, but we didn’t want to kill the deal,” says Illingworth, who, back in 1990, had proposed a $2 billion budget and 2009 completion date. “It’s politics. Most people in Congress are bottom-line oriented. You can say [of a proposed budget], ‘This is impossible,’ but then they’ll say, “Well, we don’t wanna do this.’ So you think, Okay, let’s see what we can do. It’s a balancing act.”

Initially, NASA thought it could tamp down costs by leveraging existing technology. “I think we were a little naive about how unique the JWST was,” Illingworth says. “We had to develop new capabilities that had never been flown before. That costs money because you have to test the hell out of it.”

I’m sure there were people in Congress saying, ‘God, we should have canceled this thing back in 2011.’”

Garth Illingworth

When cost projections ballooned to $8 billion in 2011, the U.S. House Committee on Appropriations, which allocates government spending, voted to cancel the project. It took an outpouring of support from the public and the science community to regain political backing. When more engineering problems delayed its 2018 launch date and required additional funds to fix, “Congress went ballistic again,” Illingworth says, laughing. The House begrudgingly coughed up another $800 million in 2019, but not without admonishment.

“At that point, we’d already spent nearly $8 billion, so it was pointless to cancel it,” Illingworth says. “Although I’m sure there were people in Congress saying, ‘God, we should have canceled this thing back in 2011.’ ”

Illingworth still rankles at the NASA-funded astronomers who called for canceling the JWST to free up money for their own projects. “What they didn’t realize was, that money would just go to other government agencies, not back to NASA,” he says. “There are only about 10,000 astronomers worldwide. If wasn’t for big projects, our visibility as a community would be much less. When they’re canceled, we need the community to come together.” He notes such dissenters are less vocal these days, given increasing support from younger astronomers who have utilized the Hubble. “They see the value in getting these amazing data sets.”

By that point in the project’s progress, Illingworth had migrated from observatory development to consultant, serving on a number of JWST science advisory committees. Bely left the program in late 2000 once the conceptual phase ended, and has since authored books on telescope design, sailing, and astronomy. When Stockman retired in 2012, Illingworth became the telescope’s remaining original architect. “Garth was a political force during this late period,” says Stockman, now 75. “Garth’s work backstage in helping keep Webb as a high priority was very important.”

Lessons from the chaos

The ongoing tumult still managed to invoke some valuable lessons and procedural changes to future major mission planning. One was the need for more accurate pricing from the start. Estimates are now more realistic, Illingworth notes, with the next proposed flagship telescope, a UV optical space observatory akin to a larger version of the Hubble, already earmarked for $11 billion.

The other was a more cohesive approach to troubleshooting. In the past two and a half years, NASA and Northrop Grumman engineers, who had been working separately, joined forces to combine the observatory parts in a cleanroom at the latter’s Los Angeles headquarters, even under the pandemic shroud. Each team brought work cultures that, when blended, enabled more stringent testing and cross-checking that proactively fixed issues before they became problems.

Moving forward, Illingworth advocates that core build groups should work together from an earlier stage than they had previously. “That was a huge change to the benefit of the program,” he says. “With such complex systems, there’s a tendency for groups to want to do the things the way they’ve always been doing it. But when it’s the first time you ever do these things, which it is on a mission like this, the more eyes you have on it with different backgrounds, the better.”

Given the recent mechanical hiccups causing incremental launch delays since the fall, Illingworth plans to wear his JWST socks and mirror pin to the early-morning launch viewing “and think positive thoughts about how well JWST has been built and prepped.” Bely flew to STScI from Paris to watch alongside Illingworth, while Stockman will be on-site in French Guiana “holding my breath until it deploys,” he says. Giacconi, who died in 2018 at 87, will no doubt attend in spirit. “He would have been absolutely delighted,” Illingworth says.

Despite Illingworth’s anticipation of the new discoveries ahead, JWST’s transition to this new chapter brings some wistful notes.

“Having worked on this for so long, I’m going to miss the interactions with so many amazing people who worked together to bring this about,” Illingworth says. “There were a lot of points when it could have died. But if this mission turned out to be easy, it would have meant we weren’t ambitious enough.”