When the Hubble Space Telescope launched in 1990, it produced mind-boggling images that changed the way we think about space.
But before the Hubble even lifted off, engineers were already planning its successor.
After decades of engineering, years of delays, $10 billion and a name controversy, the James Webb Space Telescope (JWST) will finally launch on Dec. 22.
A collaboration between NASA, the European Space Agency and the Canadian Space Agency, JWST will help us understand how the earliest galaxies in the universe formed and bolster the search for life beyond Earth.
“JWST is, in a lot of ways, the most powerful scientific instrument that we’ve ever made as humans,” says UCSC professor Brant Robertson.
The Hubble Space Telescope orbits the Earth and captures images mostly in the visible light spectrum, but JWST will operate in the infrared.
Working in this wavelength of light, scientists will soon peer behind dust clouds and see some of the oldest galaxies in the universe.
Space is expanding, so as light travels through the universe, its wavelength stretches out. It becomes redder—and eventually infrared—in a phenomenon called redshift. This means the most distant galaxies from Earth appear redder to us, as the light has traveled billions of light years before reaching us.
To detect infrared light from these ancient galaxies, JWST needs to avoid as much heat and light-pollution as possible. Even a tiny amount of nearby infrared radiation would interfere with the sensitive camera.
The telescope will fly about a million miles away from Earth and deploy a sunshield to block heat and light from the Earth, Sun and Moon.
JWST will end its journey at a stable gravitational point called L2, where it will orbit the sun from behind Earth.
Far out of human reach, the telescope must operate on its own. If something goes wrong, the instrument is literally beyond repair.
A 21-foot primary mirror, made of beryllium and coated with an ultra-thin layer of gold, reflects infrared light and helps make JWST over 100 times more powerful than Hubble.
A tennis court-sized sunshield, made of five paper-thin aluminum and silicon-coated Kapton layers, keeps it a cool -370 degrees F.
But the enormous primary mirror and sunshield won’t fit on a rocket. So engineers began practicing their origami and came up with a solution: They folded it.
Before it begins revealing the secrets hidden in the stars, JWST must successfully unfold and arrange itself.
Over the course of 29 days, hundreds of pulleys and cables will move 18 hexagonal sections of mirror and the five sunshield layers into place.
“There’s a lot riding on all these mechanisms,” says UCSC distinguished emeritus professor Garth Illingworth. “There are hundreds of things where if one of them failed, we would probably lose a lot of capability or even lose the mission.”
After the first anxious month, the telescope will cool down and spend five months calibrating its four main scientific instruments: The near-infrared camera (NIRCam), the near-infrared spectrograph (NIRSpec), the mid-infrared instrument (MIRI) and the fine guidance system/near-infrared image and slitless spectrograph (FGS/NIRISS).
Each of these tools will help researchers learn about the origins of galaxies and planets. The telescope will open our eyes to the universe in ways we can’t yet imagine.
“I can tell you what science I think Webb is going to do and the questions that I’m excited to have answered. But really, at the end of the day, the most exciting things Webb will do are the things that I can’t tell you about: the surprises, because we’re looking at the universe in a different way,” says UCSC professor of astronomy and astrophysics Natalie Batalha.
JWST is an international effort, but Santa Cruz has made a huge impact. Several UCSC researchers will lead or participate in JWST programs, and a few were also instrumental in the telescope’s development.
Life, the universe and everything
Garth Illingworth began working on the project in the 1980s, when it was called the Next Generation Space Telescope. Illingworth chaired the JWST Science Advisory Committee for eight years.
“That was a committee that was set up to look at how to maximize the science return from James Webb,” says Illingworth.
The committee would discuss everything from telescope operations to funding and data rights.
“One of the aspects of these missions, which I find to be not very good, is that people can keep the data to themselves for a year,” he says. “We felt that having a lot of data that wasn’t accessible to others was not only in a way unfair, but very unwise for a big, publicly funded facility.”
NASA opted not to reduce the one-year period of data exclusivity—called a discretionary period. So the committee came up with a compromise. They proposed an early-release science program, where data will immediately become public for certain projects.
Illingworth also helped save the telescope from extinction. As JWST’s price tag increased and delays pushed the launch date back, representatives considered scrapping the project all together.
“You don’t get congressional support just by having great ideas,” says Illingworth. “When you’re spending that much money, you’ve also got to work with politicians and staff to gain their support and interest.”
The director of NASA’s Goddard Space Flight Center at the time asked Illingworth and a few others to review the project.
“We were sort of a quiet little group,” he says. “We would sit and watch and talk amongst ourselves and then get back to people later with things that we were concerned about.”
By the end of it all, Illingworth felt optimistic.
“They really came together and produced what was a good telescope and overcame obstacles and kept the scientific capability,” he says. “So I think at this stage, we’re in great shape.”
After the launch, Illingworth’s roles will shift to, among other things, examining data from JWST as the U.S. lead for a program called PRIMER.
The project will help scientists understand the first galaxies of the universe and provide public data immediately.
UCSC astronomy and astrophysics professor Brant Robertson will also work as a co-investigator on PRIMER. He will play an even larger role on the steering committee of another first galaxies program called JADES.
JADES will use more of the telescope’s time during its first year than any other program—about 800 hours—as it takes deep images and spectra of the oldest galaxies in the universe.
In case that wasn’t enough telescope time, Robertson will also work as a lead theorist on COSMOS-Webb, another of the largest galaxy origins programs.
These research programs differ in what portions of the sky they focus on and how deep they look, but the overall goal remains similar.
“All of these surveys are geared toward trying to find extremely faint, very distant galaxies in the early universe,” says Robertson.
In some cases, scientists will be able to study how galaxies evolve over time. COSMOS-Webb will survey a large portion of sky. It will enable researchers to study the variations in density of the universe and how the surroundings of galaxies affect them.
The telescope will provide us with extremely detailed images and an overwhelming amount of data.
An interactive map of a COSMOS-Webb simulation shows just how deep into space the survey could go. It covers an area of sky equivalent to about three whole moons, and within that tiny sliver, it will image hundreds of thousands of galaxies.
To make things more manageable, Robertson worked with Ryan Hausen, a UCSC computer science graduate student, to develop and test an AI program called Morpheus. It will work pixel by pixel to classify different types of galaxies.
“I’m excited about applying AI to that survey,” says Robertson. “It’s difficult to do by eye—too many objects. And that will produce a beautiful picture,” he adds.
Planet Hunting
Several UCSC researchers will also study exoplanets, another major early goal of JWST.
Natalie Batalha began working in exoplanet research before it became a field. As a UCSC graduate student, she attended the conference where scientists first announced the discovery of an exoplanet orbiting a normal star.
She ended up working on NASA’s Kepler mission in 2000, which revealed thousands of planets orbiting stars in the galaxy.
Now, Batalha serves as the presidential chair for the UCSC Astrobiology Initiative, an interdisciplinary group working to understand the formation of life and its prevalence in the universe.
“The diversity of planets in the galaxy far exceeds the diversity of planets in our own solar system,” says Batalha. “And in fact, one of the most common types of planets that we know about in the galaxy are a type of planet we don’t have in our solar system.”
These planets fit somewhere between gas giants and small terrestrial planets in size.
“We don’t even know what to call them,” says Batalha. “Are they scaled-up Earth-sized planets? Are they scaled-down Neptunes? We don’t know.”
Some of these terrestrial planets might have started out as gaseous and lost their atmospheres over time to radiation.
“Could a planet like that be potentially habitable? What are the implications for life?” asks Batalha.
Current methods allow exoplanet researchers to measure things like mass and radius. But JWST will allow scientists to go further and tease apart the chemical makeup of exoplanet atmospheres. The spectrographs aboard JWST help make this possible.
“It is largely going to be collecting light and spreading it out into a rainbow. And then looking in great detail at the amount of energy that we’re receiving at every single individual color,” says Batalha.
She will join her daughter, Natasha Batalha of the NASA Ames Research Center, to collaborate on the largest exoplanet program in the first phase of JWST research.
Other UCSC scientists, including Jonathan Fortney, Andrew Skemer and postdoctoral researcher Aarynn Carter, will lead different types of JWST exoplanet research programs, including direct imaging.
“We’re going to be James Webb exoplanet central here,” Skemer said in a press release.
In the coming years, UCSC scientists and researchers from around the world will change the way we see the universe and our place in it. Engineers designed the instruments with growth in mind.
“It’s quite a feat to achieve these new technological advances while at the same time maintaining flexibility to respond to new scientific discoveries,” says Batalha. “Webb did that beautifully.”
If successful, JWST could create entirely new fields of astronomy.
“We’re going to probably find more questions than answers,” says Illingworth. “But it’s also the case that we will reveal a hell of a lot with James Webb.”
