When the US, Europe, and Canada first unveiled the plans for the James Webb Space Telescope in 1997, it sounded like a pitch from an overambitious science student. The contraption would have to schlep a 26-foot-wide mirror across the solar system, while keeping its cool around the radioactive sun. But to build the Next Generation Space Telescope (as it was called at the time), astronomers had to think big. Hubble, the preeminent space telescope, needed a successor—and there were too many open questions about the Big Bang and the expanding universe.
So it’s fair to say, the stakes are higher than imagined. As the world cautiously waits for the telescope to kick off its decade-long mission (the launch date is currently set for Christmas morning), here’s a look back on what it took to prepare it for this moment.
An early concept for the James Webb Space Telescope—known at the time as the Next Generation Space Telescope—was designed by a Goddard Space Flight Center-led team. It already incorporated a segmented mirror, an “open” design, and a large deployable sunshield. In 1996, an 18-member committee led by astronomer Alan Dressler formally recommended that NASA develop a space telescope that would view the heavens in infrared light—the wavelength band that enables astronomers to see through dust and gas clouds and extends humanity’s vision farther out into space and back in time. NASAA full-scale model of the James Webb Space Telescope debuted for the first time in 2013 at the South by Southwest festival in Austin, Texas. Chris Gunn/NASABall Aerospace optical technician Scott Murray inspects the first gold primary mirror segment, a critical element of NASA’s James Webb Space Telescope, prior to cryogenic testing at the Marshall Space Flight Center in Huntsville, Alabama. David Higginbotham/NASA/MFSCWhat looks like a giant golden spider weaving a web of cables and cords, is actually ground support equipment, including the Optical Telescope Simulator (OSIM), for the James Webb Space Telescope. OSIM’s job is to generate a beam of light just like the one that the real telescope optics will feed into the actual flight instruments. This photo was taken from inside a large thermal-vacuum chamber called the Space Environment Simulator (SES), at the Goddard Space Flight Center in Greenbelt, Maryland. The golden-colored thermal blankets are made of aluminized Kapton, a polymer film that remains stable over a wide range of temperatures. The structure that looks like a silver and black cube underneath the “spider” is a set of cold panels that surround OSIM’s optics. Chris Gunn/NASAJust like drivers sometimes use snow to clean their car mirrors in winter, two Exelis Inc. engineers are practicing “snow cleaning’” on a test telescope mirror for the James Webb Space Telescope at NASA’s Goddard Space Flight Center. By shooting carbon dioxide snow at the surface, engineers are able to clean large telescope mirrors without scratching them. This technique was only used if the James Webb Space Telescope’s mirror was contaminated during integration and testing. Chris Gunn/NASANASA engineers inspect a new piece of technology developed for the James Webb Space Telescope, the micro shutter array, with a low light test at NASA’s Goddard Space Flight Center. Developed at Goddard to allow Webb’s Near Infrared Spectrograph to obtain spectra of more than 100 objects in the universe simultaneously, the micro shutter array uses thousands of tiny shutters to capture spectra from selected objects of interest in space and block out light from all other sources. Laura Baetz/NASA’s Goddard Space Flight CenterNASA engineer Ernie Wright looks on as the first six flight-ready James Webb Space Telescope’s primary mirror segments are prepped to begin final cryogenic testing at the Marshall Space Flight Center. This represents the first six of 18 segments that will form NASA’s James Webb Space Telescope’s primary mirror for space observations. David Higginbotham/NASA/MFSCContamination from organic molecules can harm delicate instruments and engineers are taking special care at NASA to prevent that from affecting the James Webb Space Telescope (and all satellites and instruments). Nithin Abraham, a thermal coatings engineer, places Molecular Adsorber Coating or “MAC” panels in the giant chamber where the Webb telescope was tested. This contamination can occur through a process when a vapor or odor is emitted by a substance. This is called “outgassing.” The “new car smell” is an example of that, and is unhealthy for people and sensitive satellite instruments. Christ Gunn/NASAA bird’s-eye view of NASA Goddard’s cleanroom and the James Webb Space Telescope’s test backplane and mirrors sitting in their packing case. Chris Gunn/NASAThe James Webb Space Telescope emerges from Chamber A at the Johnson Space Center in Houston on December 1, 2017. The telescope’s combined science instruments and optical element exited the massive thermal vacuum testing chamber after about 100 days of cryogenic testing inside it. Scientists and engineers at Johnson put Webb through a series of tests designed to ensure the telescope functioned as expected in an extremely cold, airless environment akin to that of space. Chris Gunn/NASAThe Kapton® polymer-coated membranes of Webb’s sunshield were fully deployed and tensioned in December at Northrop Grumman in Redondo Beach, California. Northrop Grumman designed the observatory’s sunshield for NASA. During testing, engineers sent a series of commands to spacecraft hardware that activated 139 actuators, eight motors, and thousands of other components to unfold and stretch the five membranes of the sunshield into its final taut shape. A challenging part of the test is to unfold the sunshield in Earth’s gravity environment, which causes friction, unlike unfolding material in space without the effects of gravity.For launch the sunshield will be folded up around two sides of the observatory and placed in an Ariane 5 launch vehicle, which is provided by the European Space Agency. Chris Gunn/NASAReaching a major milestone, technicians and engineers successfully connected the two halves of the James Webb Space Telescope for the first time at Northrop Grumman’s facilities in Redondo Beach, California. To combine both halves of Webb, engineers carefully lifted the telescope (which includes the mirrors and science instruments) above the already-combined sunshield and spacecraft using a crane. Team members slowly guided the telescope into place, ensuring that all primary points of contact were perfectly aligned and seated properly. Next the team would have to electrically connect the halves, and then test the electrical connections. Chris Gunn/NASATechnicians and engineers working to ensure the soundness of the James Webb Space Telescope by manually lower its folded sunshield layers for easier access and inspection. After being lowered, engineers thoroughly inspect all five layers of the reflective silver-colored sunshield for any issues that may have occurred as a result of acoustic testing. Acoustic testing exposes the spacecraft to similar forces and stress experienced during liftoff, allowing engineers to better prepare it for the rigors of spaceflight. Chris Gunn/NASAThe arrival of the James Webb Space Telescope to Port de Pariacabo in French Guiana on October 12, 2021. It traveled from California, through the Panama Canal, aboard the MN Colibri. 2021 ESA-CNES-Arianespace/Optique vidéo du CSG – JM GuillonThe Ariane 5 core stage is 5.4 meters in diameter and 30.5 meters high. At launch it will contain 175 tons of liquid oxygen and liquid hydrogen propellants. With its Vulcain 2 engine it provides 140 tons of thrust. It also provides roll control during the main propulsion phase. This rolling maneuver will ensure that all parts of the payload are equally exposed to the sun which will avoid overheating of any elements of the James Webb Space Telescope. Chris Gunn/NASAThe James Webb Space Telescope atop its launch vehicle, before it was encapsulated in the rocket fairing. A protective clean tent was placed around the telescope until launch time. Chris Gunn/NASA
For GREAT deals on a new or used Chevrolet check out Weeks in Benton TODAY!
Life as we know it shouldn’t be able to survive in Venus’s swirling atmosphere of carbon dioxide and sulfuric acid. Its clouds are so acidic, in fact, that they don’t even register on the regular pH scale. But a new study published in the Proceedings of the National Academy of Sciences suggests that under the right circumstances, certain lifeforms could make a home for themselves by producing ammonia in the planet’s toxic clouds.
The clouds of Venus contain a few tantalizing anomalies—and the unanswered questions for why these anomalies exist leave open the possibility for life on the planet. Researchers have found, for instance, that the concentration of sulfur dioxide dramatically drops higher up in the atmosphere without a known explanation.
To understand why this depletion occurs, Paul Rimmer, a postdoctoral researcher in astrochemistry at the University of Cambridge and co-author of the new study, examined the chemical makeup of the sulfuric acid droplets in the high clouds. There, “instead of being like pure battery acid, it’s a bit more like stomach acid,” Rimmer says. “Still very acidic, but not as acidic.”
Researchers had theorized that acid-neutralizing salts could be swept up into the clouds from the planet’s surface–but the amount of mineral salt needed is too extreme, according to Rimmer’s previous calculations. Now, the research team has proposed a new hypothesis to explain the acidity anomaly: What if the cause wasn’t a mineral from the surface, but a substance produced in the clouds?
The researchers created a model using ammonia, NH3, as the neutralizing agent. Ammonia had been unexpectedly detected in the cloud layers in the 1970s by the Venera 8 and Pioneer Venus probes. This ammonia could be a sign of metabolic activity naturally occurring on Venus—meaning that the atmosphere is home to some form of life, according to Janusz Petkowski, an astrobiology research scientist at MIT and co-author of the paper.
When Rimmer and his colleagues added ammonia into their model of chemical reactions in Venus’s clouds, the ammonia explained the known abundance of water vapor and oxygen in its atmosphere. Chemical pathways involving this compound can also explain previously detected sulfite salts in the cloud droplets.
The harsh conditions in this atmosphere are not unlike extreme environments on Earth, such as the Dallol sulfur pools of Ethiopia, where luminescent yellow pools harbor a few hardy species of bacteria. What’s more, microorganisms on Venus might be shaping their own habitat to be less harsh by producing the ammonia that neutralizes acid. “If life on Venus exists, and if it indeed is responsible for making ammonia, then it makes its own environment in which it lives. It adapted,” says Petkowski.
While ammonia provides a neat solution in this model, this doesn’t necessarily mean that the ammonia is a result of biological processes.
“The responsible thing to do as scientists and astrobiologists interested in this is that we have to cultivate the habit of mind where we assume it’s everything but life first,” says David Grinspoon, a senior scientist at the Planetary Science Institute who was not involved with this research. “There are other things that can happen” in an atmosphere to produce these gases, he says, calling for experts to “rule out everything else” before making claims about life on Venus.
The study authors acknowledge that, while ammonia is a byproduct of life on Earth, the ammonia found on Venus may not be created in the same way. There might be non-biological ways of producing ammonia on other planets that we’re not currently aware of, Rimmer explains.
And even if life on Venus isn’t responsible for ammonia, Grinspoon says, there is still some exotic chemistry at play that is worth trying to discover.
For Rimmer, the key to making further assessments is to have new atmospheric probe data with more advanced technology to make sure that existing data from the 1970s and 1980s did not include anomalous results or false positives.
Interpreting data from the old instruments on the probes is actually quite tricky, Grinspoon adds, posing another problem for making inferences from those initial measurements.
In about a decade, scientists may receive a bounty of data on this cloud chemistry. NASA has scheduled the DAVINCI+ atmospheric probe, planned to launch in 2029, to carry out the first complete compositional study of the entire cross-section of Venus’ atmosphere. Another initiative by private spaceflight company Rocket Lab aims to send a probe to look for biosignatures in Venus’ clouds by 2023.
Meanwhile, Petkowski and the other authors are pushing their colleagues to rethink what it means for a planet to be habitable.
“We should not overextend our understanding of life’s adaptations to absolutely every planetary body everywhere, because our life has never had an environment like the clouds of Venus to even consider adapting to,” says Petkowski. “And so life on Venus, if it exists, is not like life on Earth. It’s life as we don’t know it. The only question is, to what degree it is different?”
In 1609 Galileo Galilei pointed a telescope with a lens no wider than a cucumber slice to the heavens to decipher the moon’s cratered surface. Since then, telescopes have become invaluable instruments in our understanding of the vast, unexplored cosmos. Observations of the night sky sparked new theories of the Milky Way and other galaxies near and far, and so came better devices to test them with. We’ve come a long way adding larger mirrors, coatings, more refined optics, and blasting telescopes into space.
“Astronomy is one of the older fields of study, but for the vast majority of the history of science, we’ve been limited to what we can see with our eyes in the night sky,” says Caitlin Casey, an astronomer at the University of Texas. “The development of the telescope in the 1600s was really transformative, and it allowed us to peer deeper and deeper into the cosmos. That just led to one mystery after another; there are some answers, but more questions.”
More than four centuries after Galileo peered into the cucumber-thin lens, NASA is scheduled to launch the largest, most powerful, and most hotly anticipated telescope ever put into space. For three decades, the public has gotten used to seeing space through the Earth-orbiting Hubble Space Telescope. Billed as Hubble’s scientific successor, James Webb (which has some controversy behind its naming) will be able to track down light from the universe’s infancy, which we know precious little about.
“It’s by far the most complex science mission that we’ve done,” says Lee Feinberg, Webb optical telescope element manager at the NASA Goddard Space Flight Center, who has worked on the observatory’s optics for the past two decades.
Fourteen years behind schedule and 20 times over budget, Webb has faced a lot of bumps on its way to the spaceport in Kourou, French Guiana. (The team pushed back the launch date to December 24 last week due to a faulty data cable.) But after more than a thousand scientists, technicians, and engineers from 14 countries overcame the challenges that emerged in its development, the telescope is finally ready to zoom away in search of “first light,” bringing astronomers closer to the Big Bang than ever before.
An early blueprint of the James Webb Space Telescope. NASA
A giant mirror built for time travel
Milestones in optics and imaging technology have enabled astronomers to observe a great deal of the universe’s history. But when it comes to understanding how it began, details are still murky.
So far, telescopes haven’t allowed us to peer back far enough to see the universe’s first light, which shimmered off the earliest stars that burst into life. Webb, however, is decked out with the latest technology specifically designed to collect and focus on that faint glow.
Size is part of the solution. The orbiting observatory will use a colossal mirror forged from featherweight beryllium—chosen because it holds its shape at extremely cold temperatures. The metal and glass is assembled into a honeycomb shape that spans more then 21 feet across; the 18 hexagonal mirror segments can unfold and are very efficient at collecting light. “Even by ground-based telescope standards, it’s a good-sized telescope,” says Marcia Rieke of the University of Arizona’s Steward Observatory, who has been on the working group for the Webb project since the late 1990s.
Project scientist Mark Clampin is reflected in the honeycomb mirrors as they’re assembled at the Marshall Space Flight Center. Ball Aerospace
Like the Hubble Space Telescope, which has been orbiting Earth for 31 years now, Webb is a Cassegrain reflector-type telescope; it uses a primary mirror to collect light and focus it on a secondary mirror, re-reflecting the energy on its four state-of-the-art instruments, including three ultra-sensitive cameras, to create an image. The larger the mirror’s area, the more light it can collect to document faint objects at greater resolution—think of it like increasing your camera’s aperture, Rieke explains. When astronomers get data back from Webb’s Earth-facing antenna starting in the summer of 2022, they’ll be better images than those taken by Hubble and other existing telescopes in outer space.
The James Webb Space Telescope picks up infrared light that is just outside of the part of the spectrum that’s visible to human eyes. There’s a good reason for this: Due to the expansion of the universe, light from distant objects shifts to longer wavelengths at the redder end of the spectrum. What’s more, newly formed stars and planets are hidden behind dust that soaks up visible light. Webb’s infrared gaze will be able to pierce through that dust, revealing what’s behind.
Three of Webb’s four detecting instruments (an imaging camera and two different Near Infrared Spectrographs) cover the whole infrared wavelength range—from 0.6 to 28.8 microns. Rieke helped design the telescope’s Near-Infrared Camera (NIRCam for short) and will be its principal investigator upon its launch. With it, Webb will be able to take clearer images from unexplored corners across the universe, capturing the light from galaxies that are even older than the Milky Way.
The heart of Near-Infrared Camera consists of a 16-megapixel mosaic of light sensors with four separate chips mounted together. K. W. Don/University of Arizona
Webb’s mirrors are also lined with a microscopic layer of gold that reflects infrared light better than nearly any other metal. That puts them at around 98-percent reflective (compared to the typical 85-percent reflectiveness of standard mirrors), which means they can capture almost all incoming photons. “We picked gold for very technical reasons, but it [also] happens to be that it looks very interesting,” Feinberg says.
Essentially, Webb is a heat-detecting telescope, Rieke adds. But to do its job and capture the faintest hints of galaxies, some parts of the telescope need to be exceptionally cold or else all it would see is its own radiation. Webb has a tennis-court-sized sunshield—a five-layer, diamond-shaped structure made of a material called Kapton—that insulates it from solar rays and allows it to cool down to -390 degrees Fahrenheit. At that degree of frigidness, the telescope gives off so little radiation that it no longer interferes with its infrared cameras and sensors.
Though it’s often referred to as Hubble’s successor, Rieke says that Webb is really a bigger and more sensitive sibling to the Spitzer Space Telescope, which also had infrared capabilities. It had to be retired in January 2020 because it flew too far away to send back images to Earth. And they’re both successors to the Infrared Astronomical Satellite, which in 1983, was the first infrared telescope to be sent into space.
Hubble varies in that it mostly captures the same kind of light that humans can see and is only sensitive to a small portion of the infrared spectrum, “Hubble has worked tirelessly to find more and more distant galaxies,” Casey, principal investigator for Webb, says. “But it’s just really limited because it can’t push to longer wavelengths.” And when it does produce images in infrared, they’re often tainted by its own radiation.
The Sunshield test unit at a cleanroom in Redondo Beach, California. The Kapton material provides an effective SPF of 1,000,000 (suntan lotion generally has an SPF of 8 to 50). In addition to providing a cold environment, the Sunshield provides thermal stability that’s essential to maintaining proper alignment of the primary mirror segments as the telescope changes its orientation to the sun. Chris Gunn/NASA
Webb will be a busy bee once it gets its permanent home almost a million miles out into space.
More than a thousand teams of astronomers from across the globe applied for telescope time during Webb’s first year, but a project by Casey—along with Jeyhan Kartaltepe of the Rochester Institute of Technology—was among the 286 proposals approved for Webb’s first year of observations. Though most groups were given around six observing hours, Casey and Kartaltepe’s research team (consisting of about 50 people spread over the world) was granted 218 hours to conduct the COSMOS-Webb survey, which aims to gather images of half a million young galaxies created soon after the Big Bang. While some surveys look at a portion of sky the size of a pinpoint held at arm’s length, Casey says they’ll be seeing a patch of sky the size of three full moons on an average night.
The telescope’s primary mirror illuminated in the dark. NASA Goddard Space Flight Center
According to Kartaltepe, they’ll look for bubbles showing where the first pockets of the early universe were reionized—meaning when light from the first stars and galaxies ripped apart hydrogen atoms that ultimately filled up the cosmos. “We call that ‘first light,’ the first stars that were able to emit photons and that were then able to send [those energy particles] to travel through the universe to where we can see them,” Kartaltepe says, adding that the Webb telescope was originally dubbed the “First Light Machine.” Webb will also help map the earliest substances in the universe, including the still-mysterious and elusive dark matter.
Casey and Kartaltepe’s team will ultimately develop a deep field of view by observing nearby patches of sky repeatedly and stitching together broader views of the early cosmic history. Ultimately, they’ll probe star, galaxy, and dark matter distribution and the origins of our universe. The COSMOS-Webb team will also make their data publicly available for other researchers.
Because Webb works in the infrared, it will also probe the atmospheres of planets around other stars for molecules like water, methane, and carbon dioxide. The telescope’s Near Infrared Spectrograph can break up light from 100 galaxies at a time into individual wavelengths by using tiny shutters—each about the width of human hair—that only let in the photons from their target and block everything else. The instrument separate light its full spectrum like a prism, which allows researchers to sift through the environments of faraway worlds and understand their potential habitability.
Next stop, space
Now comes one of the more precarious phases in the telescope’s development: the launch from the spaceport in Kourou, French Guiana.
The James Webb Space Telescope’s NIRCam instrument is readied for shipment. Lockheed Martin
Because the James Webb Space Telescope is so large, the segments had to be folded up like origami to fit inside the 171-by-18 feet Ariane 5 rocket. Unlike Hubble, the Webb telescope won’t sit in low in orbit; once launched into space, it will take about 30 days to travel to its new perch at the depths of the universe before unfurling in a complicated dance to align its mirrors on faraway galaxies. A camera onboard will snap different sequences as the mirrors get into position, so that a team back on Earth can make adjustments in the billionths of a meter. “We need to get it to within a fraction of a wavelength of light in accuracy [in sensors],” Feinberg says, “We’ve been waiting quite a long time to actually do this.” The alignment process will take about six months, after which Webb will begin collecting data.
After its arrival at the spaceport, Webb was carefully lifted from its packing container at an angle. This is the same configuration the telescope will be in when it is inside its launch vehicle, the Ariane 5 rocket. Chris Gunn/NASA
Webb’s best images will start to appear in mid-2022, but the clock is ticking for the telescope’s highly anticipated voyage. The mission is designed with a five- to 10-year lifetime, and its remote location means that unlike Hubble, it can’t be repaired if anything goes wrong. So, it needs to work flawlessly right out of the box. After that decade of gazing far into the stars, Webb will run out of fuel and essentially become a multi-billion dollar piece of space junk—but not before it changes how we see our place in the universe forever.
“Webb started when I was in grade school,” Casey says. “It’s really phenomenal that as a species that is bound ultimately to the planet that is home, we’re able to peer so far into the cosmos as to see its own beginnings. That’s pretty profound.”
