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The Hubble Space Telescope’s successor: UCL’s contribution

By Oli Usher, on 3 November 2014

JWST NIRSpec calibration assembly. Photo credit: UCL MSSL

JWST NIRSpec calibration assembly. Photo credit: UCL MSSL

The James Webb Space Telescope (JWST), currently under construction by NASA and ESA, will be the successor to the wildly successful Hubble Space Telescope. Unlike Hubble, which specialises primarily in observing the same light our eyes see (with limited ultraviolet and infrared capabilities), JWST is specially designed to observe in the infrared.

These wavelengths are interesting to scientists as they allow them to peer through thick dust clouds which scatter visible light, revealing areas of star birth and planetary systems forming. They also reveal the distant past of the cosmos, which has been redshifted out of the visible spectrum thanks to its extreme distance. Infrared observations are extremely challenging to do from the ground as most wavelengths of infrared are absorbed by the atmosphere.

(Hubble’s capabilities in visible light will be largely replaced by a new generation of ground-based observatories, such as the European Extremely Large Telescope.)

A vast project like JWST involves numerous institutions around the world – and among their number is UCL. UCL’s Mullard Space Science Laboratory is providing part of the NIRSpec (Near Infra-Red Spectrograph) instrument, which in turn is part of the European contribution to the telescope project. JWST will also be launched from a European Ariane rocket in 2018.

NIRSpec will break down the light into its component wavelengths, allowing for precise measurements of the motion and chemical makeup of stars and galaxies.

The Calibration Assembly, pictured here, built by UCL, ensures accurate observations by periodically testing the accuracy of the instrument’s colour measurements.


High resolution images


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