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How do you create a telescope unlike anything we’ve had before? These photos show us.

NASA’s James Webb Space Telescope is transforming astronomy with its groundbreaking discoveries. For 12 years, photographer Chris Gunn documented the complex effort to build it.

March 5, 2017 In a darkened clean room at NASA’s Goddard Space Flight Center, in Greenbelt, Maryland, photographer Chris Gunn uses a two-minute exposure to blur the motion of technicians shining ultraviolet flashlights to inspect the James Webb Space Telescope (JWST) after vibration and acoustic testing. They were looking for any contaminants—dust or other particles—on the mirrors. This is one of Gunn’s favorite photographs.

Photographs byChris Gunn

ByKurt Mutchler

September 14, 2023

6 min read

If you see any photographs of the James Webb Space Telescope being built, it’s a good bet that Chris Gunn made them.

In 2009 NASA selected Gunn as the full-time scientific and technical photographer to embed with the engineering team at the Goddard Space Flight Center in Greenbelt, Maryland. He spent 12 years documenting the observatory’s construction, from the arrival of the first “chassis” to its launch into space. Did Gunn capture every nut, bolt, and mirror? “In a generic sense, yes, but I’m sure there are some nuts and bolts that I didn’t photograph,” he replies with a chuckle.

Person in white lab bodysuit and blue mask working on golden mirror with a large on people in white suits on the background. — **September 19, 2012**
Engineers inspect the first of the JWST’s mirror segments to arrive at Goddard. The 18 segments that form the giant primary mirror are designed to be very lightweight and to function at cryogenic temperatures close to minus 400°F.

People in lab coats working aboud what looks like a pile of giant silver wings. — **July 10, 2014**
Engineers at Northrop Grumman in Redondo Beach, California, prepare to unfurl a test version of the five-layer sun shield, designed to keep the new observatory cool.

“For me, the magic comes when the big pieces start to get assembled and you can start to call it a telescope,” he says. “When some of the more exotic parts, like the mirror, started to show up, you really knew that this was something special. Indeed it was.”

People in lab coats working on a structure in honeycomb shape with silver and gold segments. — **April 25, 2016**
Seven years into Gunn’s time photographing the construction, the JWST begins to take shape. In a clean room at Goddard, technicians remove protective covers from segments of the gold-coated primary mirror.

Golden honeycomb mirror near the huge cylindrical camber with open door. — **December 1, 2017**
From a lift eight stories high, Gunn captures the JWST as it is moved out of the thermal vacuum chamber where it had undergone cryogenic testing for about a hundred days at NASA’s Johnson Space Center in Houston. After the successful test, the workers’ excitement was palpable, Gunn says: “That much closer to launch.”

Four people in white coverups sealing the gate. — **January 26, 2018**
It took a team of five technicians to close the doors of the JWST’s custom-built cargo container, used to transport the observatory’s optics and instruments from the Johnson Space Center to Northrop Grumman. The container was airtight to keep contamination at bay.

According to Gunn, some NASA managers consider the JWST “to be on par with the Apollo missions from the standpoint of it being something that hadn’t been done before.” The largest instrument of its kind, the observatory is now a million miles from Earth.

(The world’s most powerful telescope is rewriting the story of space and time)

View of observatory from above. — **March 5, 2020**
For the first time, and for only 72 hours, the full observatory is assembled with the mirrors deployed in their open position—21 feet, 4 inches in diameter—and attached to the sun shield. The mirrors had to fold to fit into the Ariane 5 rocket, which launched the telescope into space.

Look from behind on people watching a huge object moving through the air. — **September 16, 2021**
Technicians watch as the bulky yet fragile JWST is laid on its side for the first time during preparation for shipping to its launch site in Kourou, French Guiana.

When Gunn witnessed the launch of the JWST in Kourou, French Guiana, on December 25, 2021, he felt a mixture of joy, anxiety, and hope. “There weren’t any tears, but I was definitely choked up,” he says. “I mean, I was speechless. The only other thing I’ve done for that length of time was stay married and raise my kid, but that’s a long time to work on a project. It was very, very rewarding.”

Rocket in the doorway opening to the green fields. — December 23, 2021
Arianespace’s Ariane 5 rocket, with the JWST on board, is positioned in the final assembly building before being rolled to the launchpad at Europe’s Spaceport, at the Guiana Space Center in Kourou.

Flames and smoke from the rocket taking over and reflecting in the body of water on the foreground. — December 23, 2021
Arianespace’s Ariane 5 rocket, with the JWST on board, is positioned in the final assembly building before being rolled to the launchpad at Europe’s Spaceport, at the Guiana Space Center in Kourou.

Based in Washington, D.C., Chris Gunn focuses on science and technology. As a contract photographer for NASA, he took the lead on documenting the building of the James Webb Space Telescope. His images have appeared in publications such as the New York Times and Popular Science, and they're featured in his book, Inside the Star Factory: The Creation of the James Webb Space Telescope, NASA's Largest and Most Powerful Space Observatory.

A version of this story appeared in the October 2023 issue of National Geographic magazine.