Giant telescope project gets serious

8 May 2008

Scientists and engineers from around the world met in Perth, Australia last month to launch the €22-million preparatory phase of the biggest project ever undertaken in radio astronomy, the international Square Kilometre Array (SKA).

South Africa and Australia are the two countries shortlisted for hosting the massive radio telescope.

The SKA will be 50 times more sensitive than any existing facility and will tackle some of the biggest questions in astronomy, including searching for earth-like planets and potential life, looking at the first objects in the universe, testing theories of gravity and examining the mystery of dark energy.

PrepSKA

The SKA preparatory project, dubbed PrepSKA, will run through to 2011, pulling together international efforts from around the world to finalise a detailed, costed technical design and develop the governance and legal framework for the SKA.

The PrepSKA programme will also conduct additional studies of the short-listed sites in Australia and South Africa that are being considered for the SKA.

Funding will be provided by the European Union, which has committed €5.5-million, and the 12 participating countries: Australia, Canada, France, Germany, Italy, Portugal, Spain, South Africa, Sweden, the Netherlands, the UK and the USA.

“Once PrepSKA is complete, there should be an agreed design for the largest array of radio antennas ever built, allowing interested countries to decide on their involvement with the final SKA project,” SKA South Africa said.

Professor John Womersley of the UK’s Science and Technology Facilities Council (STFC), the co-ordinator of PrepSKA, said the SKA “has the potential to be one of the most exciting global endeavours in science, changing the way radio astronomy is done.

“The PrepSKA project is a vital preparation stage that will allow the interested partners to bring together their different approaches and priorities and lay the groundwork for a world-class programme.”

4 000 antennas

Construction of the SKA is due to start in 2013, subject to successful funding proposals, and to be conducted in phases over seven years. The telescope should start operating in 2015, once a significant portion of the array has been commissioned.

The array will comprise approximately 4 000 antennas spread out over a total collecting area of a square kilometre. The antennas will be distributed in about 200 “stations” spread over approximately 3 000 kilometres.

If South Africa wins the bid to host the SKA, the core of the telescope – consisting of approximately 3 000 antennas – will be located in the Karoo region of the Northern Cape province, approximately 95km north-west of Carnarvon. The other antenna stations will be distributed throughout South Africa and a number of African countries.

South Africa will play a leading role in much of the PrepSKA study, thanks to the knowledge and experience gained in the design and construction of the MeerKAT, an SKA prototype or “pathfinder telescope”.

According to SKA South Africa, SA’s report on the MeerKAT project “was very well received” by the nearly 200 delegates at the SKA Forum in Perth in April. These included the international agencies that will fund the SKA, as well as astronomers, industrialists and government officials.

South Africa’s MeerKAT project

Work on the design, development and construction of the MeerKAT, located at the site selected for the SKA, began in 2004 and is due for completion and commissioning by the end of 2012.

The MeerKAT has been designed by South Africans “in collaboration with the best universities and institutes in the world, including Cambridge, Oxford, Manchester, Berkeley, Caltech, the Netherlands Institute for Radio Astronomy, Astron and others,” said SKA South Africa.

The MeerKAT “is intended to be a world-leading centimetre-wave radio telescope for many years”, eventually comprising up to 80 12-metre antennas.

A 15-metre prototype antenna has been built from composite materials at the Hartebeesthoek Radio Astronomy Observatory in Gauteng province.

“This is the first large antenna in the world to be manufactured from composites,” said SKA South Africa. “Tests on this antenna have improved the design, and an optimized 12-metre antenna will be constructed for a seven-dish array to be constructed in the Karoo by the end of 2009.

“The final phase will see the construction of the array of up to 80 dishes by 2012.”

SKA South Africa is a project of the Department of Science and Technology, managed via the National Research Foundation.

SAinfo reporter

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