Made in Britain: Nasa's new infrared eye

Image copyright Miri european consortium
Image caption UK scientist Alan Pearce working on the Miri

All good things must come to an end, and the Hubble Space Telescope - the most successful scientific instrument ever launched into space - is due to reach the end of its working life some time after 2014.

But all is not lost. Step forward the James Webb Space Telescope. A bigger and - so they hope - better "eye in the sky" that will carry forward the Hubble baton, dramatically extending and improving our view of the universe when it launches in 2018.

With a primary mirror boasting a collecting area of 25 square metres the JWST is certainly a lot bigger. So big in fact that that mirror has had to be constructed from 18 interlocking hexagonal segments and protected by a sunshield that, when unfolded in space, will be the size of a tennis court. It will also operate much further from earth, orbiting far beyond the moon at the second LaGrange point some 940,000 miles into space.

Unlike Hubble the JWST will see in the infrared spectrum, allowing it to peer through clouds of interstellar dust and gas to observe the earliest stars and the formation of the first galaxies.

And that's where we come in. A central component of the Webb telescope's visual system is the Mid InfraRed Instrument, or Miri, that's been designed and built by British and European scientists right here in the UK.

Media captionTom Feilden has been to see the MIRI, a key part of the new Space Telescope built by Nasa

About the size of a large hexagonal coffee table, and with its crab-like legs wrapped in insulating foil, at first sight Miri resembles a miniature flat-topped lunar lander from the Apollo era. But as Paul Eccleston, the Assembly Integration and Verification Manager explained when I went to see the instrument in a clean room at the Rutherford Appleton laboratory, this deceptively diminutive stack of electronics packs an impressive punch.

"The light comes in at the bottom, where it's reflected off the pick-up mirror and passed up into the heart of the instrument," he told me. "From there it's split between the imager and coronagraph unit and the top deck where we have the spectrometer. It may be small compared to the rest of the JWST but it's a crucial component, and it's actually the biggest flight astronomy instrument we've ever built in the UK".

One of the first elements of the Webb telescope to be completed, Miri will be formally handed over to Nasa officials at a ceremony in London later today. Speaking on the programme this morning the agency's deputy director Eric Smith said the primary goal for the JWST would be to use the infrared spectrum to see the things that Hubble couldn't.

"Hubble kind of runs out of gas when it comes to the most distant objects in the universe, and that's because the light is shifted towards the red end of the spectrum. We want to be able to see the first stars and galaxies that formed after the big bang, and we can't do that with the current generation of ground and space based telescopes."

If Newton saw further by standing on the shoulders of giants so the Webb telescope will build on the legacy of Hubble. It's good to know that at its heart will be an instrument designed and built by British and European scientists.