Space

A glimpse inside how the James Webb Space Telescope was put together

Three decades in the making, JWST is one of the most ambitious space projects ever embarked on. These photographs, from a new book, Inside the Star Factory, show how it was developed

By Gege Li

4 October 2023

A fully deployed OTIS, with the secondary mirror extended over the primary mirror, is removed from Chamber A after a successful thermal-vacuum test in 2017. Seen still in the chamber is a sunshield simulator, called the L5 Simulator, representing the fifth and innermost layer of the sunshield. The telescope would be shipped to the Northrop Grumman facility in California to be integrated with the real sunshield. I was suspended on a lift for this shot. Page 119 — JWST’s Optical Telescope Element
Chris Gunn/NASA

THESE photos offer a glimpse into an extraordinary project three decades in the making: the James Webb Space Telescope, or JWST.

Launched in 2021 on Christmas Day, JWST took its first image in July 2022, laying bare a field of never-before-seen galaxies in unprecedented clarity. It has since uncovered new exoplanets and the area around a supermassive black hole, while upending what we thought we knew about the early universe and astronomical objects such as nebulae.

Its conception, development and launch are documented in a new book, Inside the Star Factory, by photographer Chris Gunn and writer Christopher Wanjek. Taken from the book, the main image from 2017 shows JWST’s Optical Telescope Element (OTE, known as its “eye”). Its 18 gold-plated mirrors together form a 6.5-metre-wide reflector for infrared light.

Part of what makes JWST more sensitive than its predecessor, the Hubble Space Telescope, is the fact that it sees in infrared, so it can scour interstellar distances beyond the visible light spectrum. Another crucial element is the huge reflector – six times the size of Hubble’s – that allows the visualisation of far-off objects and phenomena.

Golden slumbers. The OTIS is seen here after a successful ?center of curvature? test, undergoinga nighttime, lights-off inspection. The OTIS is what we called the combined Optical Telescope Element (OTE) and Integrated Science Instrument Module (ISIM). Gotta love NASA acronyms. Page 109 — The OTE and reflector are undergoing a nighttime, lights-off inspection
Chris Gunn/NASA

The OTE and reflector are undergoing a nighttime, lights-off inspection in the image above, while the image below captures the first moments the mirrors were unveiled, as an engineer assesses the surface of one of them for any artefacts.

Webb?s 18 mirror segments, each 1.32 meters wide, were sent by truck from its manufacturer, Ball Aerospace, in Colorado, to NASA Goddard in Maryland starting in September 2012?at first one by one and then in twos and threes, as they were manufactured over a period of about a year. Each segment is relatively light, about 20 kilograms, or 46 pounds, made from beryllium with a thin coating of gold only 4.3 grams, or 0.12 ounces. Here, Matt Macias of Northrop Grumman shines a light to assess and document any artifacts on the gold surface. Normally the clean room was noisy with activity, but there was a prolonged hush when the lid for the container came off and we all saw the mirrors for the first time. I remember standing in the glow of the gold and realizing that I had never stood next to something so precious. Page 64 — Chris Gunn/NASA

“I remember standing in the glow of the gold and realizing that I had never stood next to something so precious,” writes Gunn in the book, which is out on 17 October.

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