On or soon after Friday, NASA will launch its largest—and most complicated yet—orbiting telescope into space. The James Webb Space Telescope will leave Earth origami’d into the nose cone of an Ariane 5 rocket. Then it will spend the next 29 days unfurling itself as it makes its way to its new home, almost 1 million miles away. And astronomers are kinda shitting themselves about it.
Planetary scientist Peter Gao, a staff scientist at the Carnegie Institution for Science, captured the sentiment in a tweet: “scicomm: JWST is the biggest telescope to be sent to space it will help find life and tell us how the universe started isn’t it amazing??? / astronomers: my entire career hinges on this bucket of single point failures I’m so nervous I’m crying and throwing up everywhere.” Astrophysics postdoc Erin May, who studies exoplanet atmospheres—a major focus, pun yes intended, of the new telescope—tweeted, “HOW AM I SUPPOSED TO LIVE, LAUGH, LOVE IN THESE CONDITIONS” with the hashtag #JWSTLaunchMemes. The astronomers are not all right.
Except they are, because the JWST mechanisms and machinery have been rigorously assessed and tested. Except they’re not, because that “bucket of single-point failures” contains more than 300 individual things that could each fail and bring the whole $10 billion, 13,700 pound, 30-years-in-development mission down with them. And unlike Mars missions, which will likely keep happening and happening even when one inevitably fails, a failure here could mean a much more conservative future for space observatories, and no second chance.
Merry Christmas, right?
The space telescope you’re probably most familiar with is Hubble, launched in 1990. Hubble showed us the age of the universe, the black holes at the core of nearly every galaxy, and a 3D map of dark matter, with its 7.8-foot primary mirror and cameras, spectrographs, and interferometers.
JWST expands humanity’s view by looking at the infrared slice of the light spectrum. Hubble mainly operates in the visible light spectrum and ultraviolet; JWST is built for infrared light, which has longer wavelengths. (Here’s a primer on the electromagnetic spectrum.) With its longer wavelengths, infrared light is better at slipping through dusty clouds unimpeded, meaning JWST will be able to see celestial objects hidden from Hubble’s eye. Infrared is also where you can observe the oldest galaxies in the universe. As the universe expands, wavelengths of light itself are stretched. What was once emitted as visible or ultraviolet light is now infrared.
This is how JWST will allow astronomers to see the very first galaxies, formed 13 billion years ago. It will also be able to probe the atmospheres of exoplanets, determining how Earth-like or habitable their compositions might be and peer through murky nebulae to watch stars being born. But in order to do that, JWST needs a massive mirror, 21 feet across compared with Hubble’s not quite 8. (Spitzer, NASA’s current infrared-sensing space telescope, has a mirror of a measly 2.7 feet.) Not to mention that JWST’s mirror needs to operate at cryogenically cold temperatures, since anything warmer emits infrared radiation that can obscure the delicate signals it’s sensing.
Which all leads to this complex deployment and long journey. While Hubble orbits the Earth about 340 miles up, JWST won’t orbit Earth at all but will live at a point in space known as L2, one of the Earth-sun Lagrange points. Lagrange points are gravitationally stable spots where the pull from the Earth and sun balance out a satellite’s orbital motion. L2 is 930,000 miles past Earth, in the opposite direction from the sun. Technically, JWST will be in orbit around L2, always facing the Earth and sun in one direction, for solar power and communications. This means JWST can point its cold mirrors in the opposite direction, protected by a massive sunshield, toward the depths of space.
That distant destination also means that the telescope will be on its own, no hope for a space-walk tuneup like the ones Hubble has been able to receive.
After JWST is blasted into space on its rocket, once it has separated from the rocket and is flying free, it will spend 29 days unfolding and assembling itself on its way to L2. In the first day, the solar array and major antenna will be released so the telescope can receive energy and Earthly communications, and the first trajectory corrections will be made. By Day Three, JWST will be past the orbit of the moon. The girders holding the sunshield will extend, and the mirror and main machinery will move apart by several feet. The five layers of the sunshield will be extended, gossamer-thin and about as big as a tennis court. Then the side panels of the 18-pane mirror will swing into place. All along, small tweaks will be made to the telescope’s course, so that at the end of the first month, it will settle into orbit around L2.
There are, of course, many more steps to it than that. (And after those first 29 days there are about six months of cooldown and calibration before observing can begin.) The sunshield itself has 107 restraints holding it in place for launch, each of which must release correctly for success. And indeed, for scientists whose worries aren’t just amorphous fear, the sunshield deployment is a particular sticking point. (It’s also my favorite part of the deployment to watch in animation.) Massimo Stiavelli, JWST mission head at the science and operations center at the Space Telescope Science Institute, generally maintains a calm confidence about the telescope’s prospects. (Because of a COVID-exposure day care closure, interviews for this piece were conducted over email. Thank you to the scientists interviewed for their flexibility.) Stiavelli told me, “Risk has a different meaning in a project like this. We have risks and we either find them acceptable or change things to mitigate or eliminate them. Thus, in a sense we have no residual risks that are important.” For NASA scientists and engineers, risk isn’t a feeling, it’s a quantifiable metric, and each risk is assessed, measured, tested, and addressed until the remaining risk is low enough to be acceptable. To Stiavelli, that’s equivalent to the risk not existing at all. But, he conceded, “That doesn’t mean we don’t have challenges,” and he called the sunshield deployment “one of the most challenging moments.”
Keith Parrish, observatory manager for the JWST at NASA’s Goddard Space Flight Center, was similarly sanguine—telling me that he’s been so busy that he hasn’t had time to worry—and similarly aware of the sunshield’s copious challenges. “The consequences of just one [of the 107 sunshield restraints] not releasing correctly is fairly dramatic, so I guess the sheer number of those devices  that must work correctly can be a little intimidating.”
Of course, even getting into space is hard. Astrophysicist Knicole Colón is JWST’s deputy project scientist for exoplanet science. She told me that she’s actually most anxious about the launch. “While there are a lot of deployments, we have some time to get them done (and get them done right).” The rocket ride, on the other hand, is harrowing and explosive. Once JWST is off the Earth, she’ll be able to worry about everything else.
But while those involved with the JWST launch may be mostly Zen, too busy to fret or able to channel their worry into action, many astronomers watching and waiting don’t feel quite as calm. Kevin Hainline is an infrared astronomer, a member of the science team for JWST’s Near Infrared Camera, and one of the researchers for whom JWST is going to be a career-shifting event. He knows that the people working on JWST know what they’re doing. “I know this! I am a rational person,” he told me (or reminded himself). “But I’m also an incredible engine of worry.” Hainline has been trying to busy himself with hobbies and home improvement projects, “to exhaust myself enough into falling asleep quickly.” But even that isn’t foolproof. “I had a nightmare last night about the fence my wife and I are building behind the house,” he told me, “and I woke up almost in a panic attack. This was 100 percent my JWST worries sneaking in.”
Huei Sears, a Ph.D. student at Northwestern University, studies galaxies that host long gamma ray bursts. She told me over email, of her work, “Right now, I’m looking at the highest redshift we can with current instrumentation.” (That’s the almost 20-year-old Spitzer.) “But I’m really interested in regions further than that, and JWST will allow me to do that!” Sears told me that delays, especially close to launch, are anxiety-provoking. “I’ve tried to ease my anxiety about the launch by focusing on things I can control,” which for Sears includes working on articles about JWST’s science potential and naming controversy for the grad student–run website Astrobites (where, full disclosure, I once was also a writer).
Other astronomers are almost numb after years of delays and false alarms. When the launch was pushed back from Wednesday to Friday, exoplanet researcher Jessie Christiansen tweeted, “Honestly though does anyone actually have any emotional response to JWST delays anymore? Those neurons are burned out, baby.” She followed it up: “At this point they should just stop giving us launch date updates and tell us a few days afterwards that JWST has launched.” (Which, for what it’s worth, is how I treated going into labor—I only told people once I’d had the baby.) Astrophysicist Catherine Slaughter tweeted, “The JWST launch is just astronomy’s version of that boat getting stuck in the Suez Canal—Objectively bad and anxiety-inducing, but also funnier the longer it goes on.”
Christiansen also wondered if NASA would launch the telescope on Christmas Day itself if that’s when it’s ready—are concerns like human holidays insignificant for such a cosmic plan? But the timing may be useful for anxious scientists. Sears told me that she’s trying to keep herself busy with Christmas—busy and festive and mostly offline. “I’ll check in the a.m. about the launch. If it’s good, then that will only add to the merriment of Christmas Eve; if it’s bad … well … it’s Christmas Eve, and it’s kinda hard to be sad on Christmas.”
Hopefully the seasonal spirit will carry us through the next 29 days, too.