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Scientists plan massive new space telescope ATLAST

Paul Sutherland, Feature writer
Jun 23, 2014, 14:23 UTC

Sen—The James Webb Space Telescope is still years away from launch in 2018. But space scientists are already planning its successor. And they envisage a huge new instrument that will dwarf the JWST.

No final design has yet been agreed for the new Advanced Technology Large Aperture Space Telescope (ATLAST). But it could have a light-collecting main mirror 20 metres in diameter, making it powerful enough to image exoplanets orbiting nearby stars and to check their atmospheres for signs of life.

Its great size means that it will probably have to be assembled by astronauts in space before is is deployed rather than launching on a single rocket.

US and European astronomers and engineers are collaborating on this exciting concept mission. Sen spoke to one of them, Professor Martin Barstow, of the University of Leicester, which is one of the UK’s leading space science facilities.

Professor Barstow is current President of the Royal Astronomical Society and will call tomorrow, at the National Astronomy Meeting in Portsmouth, for governments and space agencies around the world to back the project.

Professor Barstow argues that the new telescope will be a vital successor to Hubble, with its 2.5-metre mirror, and the JWST, which will have a segmented mirror 6.5 metres across. It is nearly 25 years since Hubble’s launch and it has brought a wealth of discoveries as well as stunning views of the Universe.

an exoplanet

An artist’s impression of an Earth-like planet in orbit around another star. Credit: ESO

The JWST, due for launch in 2018, is currently being assembled after surviving attempts in the US to kill it off because of the $8.7 billion cost. It will employ a revolutionary new segmented mirror that unfolds once it is in space.

Professor Barstow told Sen that ATLAST was important because, launching in around 2030, it would follow on from the work of the JWST at the end of that instrument’s projected mission life. It will allow astronomers to observe in visible light as well as the ultraviolet and infrared ends of the spectrum.

He said: “We can’t make ultraviolet observations from the ground and infrared is a bit of a struggle too. So it’s about getting wavelength coverage and the main point about a big optical telescope like this is it’s going to be the one thing that we can build that will be capable of looking at and doing diagnostic measurements of earthlike planets around other stars.

“You need the big area to get enough light because these objects will be very very faint. It depends on getting the technology right, but the principle is that you’ll be able to image the planets orbiting nearby stars and then to take spectra of the planets individually and study the atmospheres. It is looking at those atmospheres for biological signatures that is a really exciting thing.

“I should be retired by the time it operates. So this is really about the next generation of scientists, and we’re putting in the ground work now. If you don’t start now planning something like this, it won’t be ready for launch in 15 years time. If you don’t start now, you push the launch ever more distant.”

Asked why cash-stretched governments should contribute to another huge space project when they were already finding huge sums for instruments such as the ground-based Square Kilometre Array (SKA), Professor Barstow said: “Having ATLAST at the same time as the SKA is extremely important because the SKA will be a radio telescope and looking at a quite a lot of different stuff. The two telescopes will complement each other.”

He added: “ATLAST is going to cost several billion dollars but not necessarily as much as you think because you learn lessons from building the JWST. Some of the technologies from that will be important for building and developing this telescope, such as unfolding the mirrors.

“But there is also the justification that pushing the boundaries like this produces an awful lot of exciting technology that also finds applications elsewhere, so just being on board a big project has benefits. But the ultimate question—are we alone?—is a pretty fundamental one and this is the way we will answer it.”

As well as checking nearby exoplanets, ATLAST would study star and galaxy formation in high definition, constructing the history of star birth in detail and establishing how intergalactic matter was and is assembled into galaxies over billions of years.