Reach for the stars

It's a question that most of us ask ourselves at some point as we look up at the night sky, just what is out there? But, scientists and engineers are, as ever, coming up with new and innovative concepts that will hopefully provide at least some of the answers. One of the most exciting prospects is the Square Kilometre Array (SKA) programme, a €1.5 billion international project to develop the world's largest telescope. And, the UK is providing a significant chunk of expertise, both scientific and industrial, as the design and technical developments are finalised. "The UK is taking a strong role in SKA," says Andrew Faulkner, a SKA Design Studies project engineer from the University of Cambridge. "Many of the design engineers are from the UK and are involved in some of the highest performance parts of the project. "There is clearly a major opportunity for UK industry to show what it can do. Much of the frontend, the physical hardware that will make up the array, must be right and meet both cost and technical targets. It will need to operate at relatively low power, be extremely reliable, and pretty much bang on first time." Cambridge Consultants is involved in the industrial scale up of the design work and hopes that many of the technologies will be able to be transferred into other applications. It will research the fundamental technologies required to build major systems, including the antenna design, semi conductor development and the extremely high speed digital processing required to make sense of the 16 terabits of data expected to be accumulated every second. It will also facilitate several small scale projects to build physical demonstrators installations. The square kilometre refers to the collecting area of the radio telescope, which will be thousands of times more powerful than existing radio telescopes. Several technology implementations are being assessed and a hybrid system is likely to be used to get the required coverage of 0.1 to 20GHz. The first concept uses 2,500 relatively small parabolic dishes with a typical diameter of 12 to 15m. But as well as using the traditional dishes associated with telescopes, SKA is likely to use a novel phased array concept. These are small individual elements arranged in clusters. The revolutionary design being proposed uses 250 aperture array stations, each of which will be composed of tens of thousands of small antennae fixed to the ground. It is estimated around 40 million individual receiver elements will be used in all. As a result, design engineers from industry are already busy making the elements suitable for volume manufacture to get as much cost out as possible. SKA Design Studies are focussed on the development of the Aperture Plane Phased Array. This will use fast digital technology to allow the telescope to be as flexible as possible and allow multiple astronomical observations to be made simultaneously. The limiting factor will be the processing power available. Phase One of the build project will begin in 2013 with completion due by 2017. The initial phase is likely to cost some €300 million. "One of the big advantages of radio telescopes is the ability to use them progressively," says Faulkner. "So Phase One will be made operational after completion. And that will be bigger and more powerful than anything else we currently have." The array is likely to be built in either Australia or South Africa far away from dense populations, as the telescope needs to operate in near isolation. Any local radio waves, or signals from mobile phones could affect the telescopes readings. By 2022 it is hoped the project will be completed and begin to scour the Universe to hopefully unravel some of its mystery.