KEY IS TELESCOPE ALMOST READY
The Webb telescope, NASA’s golden surfer, is almost ready, again
After 30 years and a cost of $8.8 billion, NASA’s James Webb Space Telescope could be launched as early as Oct. 31.
Birthing a new space telescope takes a long time and a lot of money and inspiration. Astronomers first began pestering NASA for the successor to the Hubble Space Telescope even before that telescope was launched into orbit in 1990. Back then they thought it could cost less than $1 billion and be ready in the first decade of the 21st century.
Thirty years, $8.8 billion, multiple mishaps and budget crises, and a threatened congressional cancellation later, the James Webb Space Telescope appears to be finally ready. NASA now plans to launch it into orbit as early as Oct. 31 aboard an Ariane 5 rocket supplied by the European Space Agency, from a site in French Guiana.
During a recent meeting of the American Astronomical Society, technicians and engineers showed off the telescope for what they hoped would be the last time to humans on the ground.
“The next time the observatory looks like this,” said NASA’s Eric Smith, project manager for the telescope, “it will be beyond the moon and appear to us as a roughly 17th-magnitude point source.”
Completely assembled in its clean room at Northrop Grumman in Los Angeles, the telescope as viewed over a Zoom conference resembled a giant sunflower riding on a surfboard. The flower’s petals are 18 gold-plated beryllium hexagons joined to form a dish more than 20 feet across. The surfboard, on which it will float eternally on the far side of the moon, is a sandwich of five layers of a plastic called Kapton that will shield the telescope from the heat and glare of the sun.
The telescope, named for the NASA administrator who led the agency through the development of the Apollo program, is almost three times larger than the vaunted Hubble and seven times more powerful in its ability to discern faint stars and galaxies at the edges of time.
To get them into space aboard the Ariane 5 rocket supplied by the European Space Agency, the shield and the telescope mirror will have to be folded up, then must unfold 1 million miles out in space in a series of some 180 maneuvers in the first month after launch. The steps of that deployment have been practiced over and over in the past few years.
An early rehearsal ripped the sun shield, causing yet another delay to the project.
The engineers think they have it right now, but they refer to the impending outer-space unfolding and
testing period as six months of terror. There are still a couple of half-inch tears in the Kapton that need to be patched, Smith said.
The Webb telescope’s mission is to explore a realm of cosmic history that was inaccessible to Hubble. About 150 million to 1 billion years after time began, the first stars and galaxies were born and began burning their way out of a gloomy fog of hydrogen gas that prevailed at the end of the Big Bang. Exactly how that happened is unknown.
The mission requires the Webb to be tuned to a different kind of light than our eyes or the Hubble can see. Because the expansion of the cosmos is rushing those earliest stars and galaxies away from us so fast, their light is red-shifted to longer wavelengths.
Thus, blue light from an infant galaxy way back then, bursting with bright new stars, has been stretched to invisible infrared wavelengths — heat radiation — by the time it reaches us 13 billion years later.
As a result, the Webb telescope will produce cosmic postcards in colors that no eye can see. But to detect those faint emanations of heat, the telescope must be very cold — less than 45 degrees Fahrenheit above absolute zero — so that its own heat does not wash out the heat from outer space. Hence the need for the sun shield, which will keep the telescope in permanent, frigid shade.
As it turns out, infrared emissions are also ideal for studying exoplanets, worlds that belong to other stars.
The ungraying of astronomy
That search for life is front and center in a new documentary film about the Webb telescope, “The Hunt for Planet B,” which was made by Nathaniel Kahn and will premiere at the South by Southwest Festival in March. The film, somewhat to Kahn’s surprise, also documents a sociological revolution in astronomy — namely, that many of the leaders in the field of exoplanets are women.
Feature billing goes to researchers such as Jill Tarter of the SETI Institute, a pioneer in the search for extraterrestrial civilizations; Natalie Batalha of the University of California, Santa Cruz, a leader of the Kepler mission who is now planning Webb observations; Margaret Turnbull, an expert on habitable planets at the University of Wisconsin, whom Kahn interviewed as she tended her backyard beehives; and Amy Lo, a Northrop engineer who works on race cars when she is not working on making all the Webb pieces fit together.
“It doesn’t matter what I think,” Tarter said when asked by Kahn about life in the universe. The pundits and priests have been removed from the equation: “We’re not doing religion here, we’re doing science.”
Kahn is a longtime amateur astronomer. He had set out to make a film about the building of the telescope, but one of the joys of filmmaking, he said in an interview, is that “you start out making it about one thing, Webb, and it evolves naturally into a much deeper story. And that’s really the emergence of women at the forefront of astronomy.”
Sara Seager, a planetary expert at the Massachusetts Institute of Technology, whose story helps frame the film’s narrative, said the emergence made perfect sense. “When exoplanets was a brand new field, the field by definition couldn’t be dominated by old white men,” she said. “In fact, older scientists were reluctant to jump into a brand new and seemingly risky field, so there were few to no people to inflict their biases on the community.”
Seager recalled being shocked when she started attending cosmology conferences that almost all the speakers were men with white or gray hair. “Simply, in cosmology there were no niches for new types of people to join,” she said. “In the exoplanets subconference, no one was over age 40 and most were under age 30.”
Forward to the past
So far 4,332 astronomers from 44 countries, 45 U.S. states, the District of Columbia and the Virgin Islands have submitted proposals for the first round of Webb observations, according to numbers supplied by Christine Chen of the Space Telescope Science Institute during the Webb show-and-tell. About 31.5% of the researchers are female, which roughly tracks with recent statistics that one-third of astronomy doctorates go to women.
“We naturally have diversity built into it,” Smith, the project manager, said of the Webb program during the recent Zoom broadcast.
He added: “As scientists, we also know that the universe reveals itself rarely through data that conform to our models or theories, that rather it is those data that lie outside our expectations that point us closer to a universal truth. And so, just as we know we must seek to understand our data that are different from our preconceived notions, to understand the cosmos better, we need to seek different viewpoints when we conceive and build missions.”
The launch of Webb in the fall will be among the grand events of space science this year, along with the next robot invasion of Mars, set to occur this winter when the latest fleet of robots lands there.