Giant radio telescope may find a home in Australia

Australia has been short-listed as one of two countries to host the Square Kilometre Array (SKA), a giant next-generation radio telescope. The other country on the short list is South Africa. The SKA is being developed by scientists in 17 countries.

The finalists were chosen by the International SKA Steering Committee based on the recommendation of an advisory committee of seven scientists from five countries that examined four site bids.

The SKA will be a set of thousands of antennas spread over 3000 km, with half the antennas located in a 'core' site of 5 x 5 km. The proposed core site in Australia is Mileura station, 100 km west of Meekathara in Western Australia. Other antennas would be distributed over the continent and still more might be placed in New Zealand.

Australian SKA project director, Professor Brian Boyle of the CSIRO Australia Telescope National Facility welcomed the news.

"This is a major milestone for the SKA project," Boyle said.

The Australian candidate site is a radio-quiet site with the very high sensitivity levels needed for the SKA and an extremely low population density. It features a high level of sky coverage and ionospheric stability and also has a benign troposphere and dry climate.

The community itself is a strong radio-astronomy community with existing infrastructure. In a country the size of Australia, all remote array-stations would be in the one country and also have the option of additional array-stations in New Zealand.

The telescope will be vastly more sensitive than the best present-day instruments, thus enabling astronomers to look for cosmic signals from the early universe. The SKA will be capable of answering identified major physics and cosmology questions, tackling the structure and evolution of the early universe and understanding the nature of cosmic magnetic fields, gravitational radiation and dark energy.

The SKA will also be able to answer a number of questions such as: Are there earth-like planets around other stars?, Is Einstein's theory of General Relativity correct in the strong field limit?, What is the origin and evolution of cosmic magnetism?, What is the equation of state of dark energy and does it change with cosmic time?, How do galaxies assemble and evolve?, and What happened during the so-called 'epoch of re-ionisation' in the extremely early universe?.

The site submission was developed by the Australian SKA Planning Office in CSIRO, with the help of the WA government and consulting firm Connell Wagner.

"We've got a great site, but we've also got a team that's worked very hard to present its greatness," said Dr Bob Frater, chair of the Australasian SKA consortium committee.

"This result is a tribute to them."

The SKA will also benefit Australia by providing opportunities for Australian companies to engage in a large-scale project in an advanced ICT area and for Australian scientists and students to be involved in world-leading scientific endeavours.

The SKA is an iconic project that can showcase Australian high-technology capability and scientific sophistication. It will also provide sustainable, long-term employment opportunities in regional Australia while enabling the installation of significant telecommunications infrastructure.

There will be opportunities for Australian companies to become involved both in the construction and in the operation and maintenance of the SKA, as well as in the research and development leading up to the construction. Australian companies are already working with Australian scientists and engineers to develop the pre-cursor telescopes to be sited at Mileura.

The target budget for SKA is €1 billion, with maintenance/operational costs of around €100m. The expected lifetime of SKA is at least 50 years.

Both the Australian and South African sites can see much of the same sky as the world's other major telescopes. Both have a good view of the southern sky, which is where the centre of our galaxy goes overhead. And both have stable ionospheric conditions, which is important for low-frequency observations.

China and Argentina also put in a bid to host the SKA. While these sites were considered excellent for radio astronomy, they failed to meet at least one of the SKA's exacting requirements.

The proposed site is in an extremely sparsely populated area of semi-arid land in rural Western Australia. The population density of the council area of the core site is less than 0.004 people per square kilometre.

According to Dr Michelle Storey, Australian SKA Planning Office Leader CSIRO ATNF, the current Mileura Station managers and other pastoralists in the area are in favour of the SKA being built, and the local indigenous communities have also expressed strong support for the project, as have communities in the nearest towns.

There will be no health risks for humans or animals involved in living near the SKA. This is because the SKA antennas do not transmit in any way - they only detect the radio radiation that is being emitted from space.

"CSIRO continues to work on the extended New Technology Demonstrator telescope to be sited at Mileura. In addition, a consortium led by MIT in the USA and involving a number of Australian universities and CSIRO is working on a low-frequency demonstrator telescope to be sited at Mileura, with initial deployment scheduled for December 2007," said Storey.

The final siting decision is expected by 2010.