Spaceflight Insider

James Webb Space Telescope now fully equipped with science instruments

The James Webb Space Telescope primary mirror

The James Webb Space Telescope primary mirror. (Click for full view) Photo Credit: NASA / Chris Gunn

A team of some two dozen NASA technicians and engineers have successfully installed the package of four science instruments that will accompany the James Webb Space Telescope (JWST). The instrument package comprises a collection of cameras and spectrographs that JWST will utilize to record astronomical observations made with its 6.5-meter (21-foot) golden mirror.   

It has been a long journey for NASA’s successor to the Hubble Space Telescope. Design work on the JWST began nearly 20 years ago; the structure was completed and the mirrors installed earlier this year.

The JWST team crane lifting the science instrument package for installation into the telescope structure.

In this rare view, the JWST team crane lifted the science instrument package for installation into the telescope structure. (Click to enlarge) Photo Credit: NASA / Chris Gunn

Current plans call for JWST to be launched in 2018 on top of an Ariane 5 rocket from French Guiana.

Made in the US, Europe, and Canada, the science instruments were sent to NASA’s Goddard Space Flight Center in Greenbelt, Maryland, where their installation was completed in the world’s largest clean room.

To prepare for the installation, which required highly detailed precision, the technicians and engineers were put through specialized training via computer models, a mock-up of the suite of instruments, and test runs.

Cranes were used to lower the instruments into an enclosure at the back of the telescope where they were subsequently secured.

Even conversations between personnel had to be limited to make sure all directions were accurately heard.

“Our personnel were navigating a very tight space with very valuable hardware,” said Jamie Dunn, manager of the science instruments, which have been collectively dubbed the Integrated Science Instrument Module (ISIM).

“We needed the room to be quiet, so if someone said something, we would be able to hear them. You listen not only for what other people say, but [also] to hear if something doesn’t sound right,” he explained.

The science instruments will detect light from faraway stars and galaxies collected by the telescope’s giant golden mirror.

The instruments include a Near-Infrared Camera, a Near-Infrared Spectrograph, a Mid-Infrared Instrument, and a Fine Guidance Sensor / Near InfraRed Imager and Slitless Spectrograph.

Provided by the University of Arizona, the Near-Infrared Camera, or NIRCam, is the telescope’s primary imager and covers infrared wavelengths ranging from 0.6 to five microns. It will observe the universe’s earliest stars and galaxies, stars in nearby galaxies, young Milky Way stars, and Kuiper Belt Objects.

The Near-Infrared Spectrograph, or NIRSpec, was provided by the European Space Agency (ESA), with some components from NASA’s Goddard Space Flight Center. It also operates at wavelengths ranging from 0.6 to five microns and disperses light from objects into spectra, which are used to identify individual chemical elements.

Analysis of an object’s spectra can reveal its mass, temperature, and chemical composition.

NIRSpec will study the universe’s first galaxies, which are so faint that JWST will have to observe them for hundreds of hours in order to collect their spectra.

JWST’s third science instrument, the Mid-Infrared Instrument, or MIRI, was provided by the European Consortium with ESA, and by NASA’s Jet Propulsion Laboratory (JPL).

With both a camera and spectrograph, MIRI covers wavelengths between five and 28 microns. Its camera will provide the wide field, broadband imaging for which the Hubble Space Telescope is famous, while its spectrograph will give researchers information about the distant objects observed.

Inside the massive clean room at NASA's Goddard Space Flight Center in Greenbelt, Maryland, where the JWST team installed the science instrument package.

View inside the massive clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland where the JWST team worked meticulously to complete the science instrument package installation. (Click to enlarge) Photo Credit: NASA / Desiree Stover

MIRI’s highly sensitive detectors will observe redshifted light of distant galaxies, stars in the process of formation, and both faint comets and Kuiper Belt Objects.

The Fine Guidance Sensor / Near InfraRed Imager and Slitless Spectrograph, or FGS/NIRISS, was provided by the Canadian Space Agency.

This instrument enables JWST to point precisely at objects so that it can obtain images of the highest quality. Its science goals include detecting the universe’s first light, finding and characterizing exoplanets, and conducting exoplanet transit spectroscopy.

It detects wavelengths ranging from 0.8 to five microns.

With instrument installation complete, the next steps for the telescope involve vibration and acoustic tests to assure it can withstand the rigorous conditions during launch.

“Designing and building something of this magnitude and complexity, with this amount of new technology, is far from routine. While every project has their share of ups and downs, the JWST team has had to work through a lot over the life of this project,” Dunn noted.

“This is a tremendous accomplishment for our worldwide team,” emphasized JWST Project Scientist and Nobel Laureate John Mather.

“There are vital instruments in this package from Europe and Canada as well as the US, and we are so proud that everything is working so beautifully, 20 years after we started designing our observatory,” he added.

JWST will study the different epochs in the universe’s history and the Solar System’s evolution. It will also search star systems for Earth-like planets that could potentially host life.


Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.

Reader Comments

Of course the presumption is that the Universe is expanding and red shift supposedly proves that to be true, however what if that assumption is wrong and the basis of all this effort is false. I hope the scientists that eventually get to see this will be open minded enough to also accept the possibility of an Electric Universe where so called inherent red shift as Halton Arp surmised actually is caused by an object being young and only secondarily because of it velocity.

N.G. Krishnan

In the unlikely event of the launch failure and loss of JWST what is the recovery plan? So much of ingenuity has gone in to the project, I am certain of contingency plan of action should the unexpected were to occur.

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