A Tangled Webb
How a former Penn soccer player helped prep a NASA telescope for its long-awaited launch.
Mike McElwain C’01 was a few months into testing the $9.6 billion James Webb Space Telescope (JWST) in 2016 when a tacky substance suddenly appeared on one of its precisely polished mirrors, threatening to significantly reduce light passing through the telescope. McElwain and his colleagues feverishly tried to decipher what it was, where it came from, and how to remove it without mucking up the whole instrument. Amidst mounting costs and delays, the last thing they needed was for some mystery schmutz to threaten humanity’s most ambitious telescope.
“It was definitely a crisis,” says McElwain, a senior research astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “People were pretty panicked, including myself. We had a huge amount of pressure.”
It took several weeks to discover the culprit. During a test run conducted at the cryogenic temperatures the telescope would encounter in space, a bit of adhesive had frozen into tiny crystals that spread across the mirror and subsequently warmed into a sticky film. Working carefully to solve the crisis, scientists used solvents and a specially designed fine bristle fan brush to systemically remove the contaminant without accidentally spreading it.
After a quarter-century of technical hurdles and an international effort involving 24 countries and three space agencies, the James Webb Space Telescope is finally slated for a December launch to an orbit one million miles away. There the four-story, 14,000-pound telescope will spend several years peering back in time, capturing and analyzing infrared light emitted 13.7 billion years ago to gather information about the composition of the early universe and how the first stars and planets formed. It will also investigate the atmospheres of exoplanets in other solar systems to find those with Earthlike conditions.
“We’re hoping to learn where we come from, our place in space, and how exoplanets form and evolve,” McElwain says. “The JWST is really going to transform all aspects of space science, from observations in our own solar system to the very beginning of the universe.
“About the time I was at Penn, they started discovering planets around sun-like stars, which is partly what got me onto this path,” he adds. “Now over 4,000 have been confirmed. Ultimately, we hope to find Earthlike planets among those, study their atmospheres, and look for signs of life. I’m actively involved in developing technologies that would enable those observations in future missions.”
Once the telescope magnifies those ancient traces of infrared light, four onboard instruments will interpret their wavelengths and beam the digitized information back to Earth. As the JWST observatory project scientist and a technical lead, McElwain helped build the telescope, integrate it with the spacecraft, and test them in simulated launch and space conditions. The telescope comprises a 21-foot diameter mirror of 18 gold hexagon reflectors, and five silver sunshields that block enough solar radiation to cool the telescope to -388˚F. It all folds to fit into a 16-foot-diameter rocket with inches to spare, to then unfurl during the first half of its monthlong journey to orbit. “We’re going to be holding our breath for those 14 days,” he says.
Growing up in York, Pennsylvania, McElwain leaned more towards sports than science, initially envisioning a coaching career. But while playing on the soccer team at Penn, he enjoyed a freshman honors physics class taught by the late FayAjzenberg-Selove, who guided him to a summer job with an on-campus research project in high energy physics. The next year, his athletics academic advisor suggested an astronomy class. “I really started seeing the connection between astronomy and my physics major,” McElwain says. “Furthermore, there were all these things we didn’t know about the universe. Dark matter, dark energy, and exoplanets were just being discovered.” McElwain later joined a campus research group studying brown dwarves, a type of low-mass star. (His research gained notice, and the Daily Pennsylvanian published a profile on him during his junior season, when he was the Quakers’ leading scorer, titled “Soccer is not rocket science for McElwain.”)
After Penn, McElwain headed to UCLA for graduate school, which had him working on infrared cameras for the W. M. Keck Observatory in Hawaii, followed in 2007 by a postdoctoral stint at Princeton University developing high-contrast imaging systems for Japan’s Subaru Telescope, also in Hawaii.
“I love the team effort of building instruments,” McElwain says. “I thrive in that environment. I think that goes back to my soccer-playing days.”
McElwain joined NASA in 2011 to work on infrared measuring instruments and technologies for future observational missions, including JWST’s successor, the Roman Space Telescope, tentatively scheduled to launch in 2026 or 2027. He joined the JWST team in 2014.
“He’s a combination of brilliant and patient,” says John Mather, a JWST senior project scientist and 2006 Nobel Prize in Physics winner for measuring radiation from the Big Bang. “He knows what he’s doing, is well organized, and takes care of things that might escape others.”
Cullen Blake, a Princeton colleague who’s now an associate professor of astronomy at Penn, continued working with McElwain on a related NASA-funded device to measure exoplanet mass now used at Kitt Peak National Park Observatory in Arizona. “He’s methodical and careful and does things right the first time,” says Blake. “He’s got a combination of technical and scientific skills and is also just very personable. It doesn’t surprise me that he’s risen to this level.”
When the JWST reaches orbit, McElwain will help lead the checkout of the telescope systems, including a calibration of its instruments to account for errant light and small temperature changes that could distort data. Once the instrument is operational, he’ll continue refining the technology while studying circumstellar discs (debris surrounding new stars) and exoplanets.
NASA’s gain is due in part to McElwain’s wife, Crystal Simpson, an investment banker who agreed to commute to New York from their Maryland home. “I considered a Princeton research faculty position so we could be closer, but she strongly encouraged me to take the NASA dream job even though that meant being apart during the week,” he says.
It’s this sense of personal and professional teamwork that’s enabled his career to unfold “absolutely beyond my dreams,” he says. “I don’t think I could have imagined or plotted a path to be where I am now. Before Penn, I didn’t know any professional scientists or have any contacts. Penn gave me the opportunity. If I didn’t have those mentors, there’s no way I’d be here.”
—Susan Karlin C’85