Astronomy: South Africa's bid to become a leader in the development of international astronomy and space projects will take a step forward with the construction of a new telescope to be built in the Karoo.
The Karoo Array Telescope (KAT) could ultimately be a component of the euro 1bn Square Kilometre Array (SKA), a global radio telescope which will span continents and probe the secrets of space . Argentina, Australia, China and SA are participants in the SKA project but are also bidding against each other to become the main site for the project. Final bid documents are due for submission by December but the winner is expected to be announced only in mid-2007.
Though SA has many geographic and weather advantages over its rivals, high telecommunications costs and uncertain regulation could well scupper its bid.
The KAT is emerging as highly strategic in SA's space science agenda. It is integral to the SKA bid and, as part of the growing network of telescopes in Southern Africa (which include those in Sutherland, Namibia and Hartebeesthoek), it will encourage scientific research in this region.
"KAT will enable us to contribute to the study of the evolution of the universe," says SKA project manager Bernie Fanaroff. "It will not be able to see as far back into the history of the universe as the SKA will allow, but we should be able to map the galaxies as they were billions of years ago, when the universe and galaxies were still quite young."
KAT will also serve as a showcase for SA technologies that are expected to be critical to the SKA project. "If we get the technology right for KAT, our participating universities and industry have a good chance of being major suppliers for the whole project, even if SA does not win the bid to host the array," says Fanaroff.
In addition, the advanced technologies that will result from the KAT project will have a positive impact on SA's ability to compete in the global high-technology marketplace.
The KAT will be an array made up of 20 dishes, each 15 m in diameter, spread out over a kilometre in the Karoo.
The project team is in the research, development and costing phase and requests for information are being sent to local, Russian, German and Chinese companies in the scientific software, digital signal processing and structural steel industries, among others.
The KAT project is also benefiting from collaboration with the universities of Oxford, Cambridge, Manchester and the University of California at Berkeley as well as the Australian National Telescope Facility and the Astronomical Institute in the Netherlands. "We have benefited from their experience and learning, which has allowed us to move quickly into cutting-edge development," says Fanaroff.
For instance, SA is collaborating on new focal-plane phased arrays that will allow the KAT to generate up to 40 beams from each dish. "It is equivalent to looking in 40 different directions at the same time ."
Though SA is competing with Australia to host the core of the SKA, the two countries are collaborating over the design of the smaller demonstrator telescopes. Australia is building its own KAT, named the Extended New Technology Demonstrator, to a different design. Both telescopes will be built by 2009, an extraordinarily tight time-frame.
These telescopes don't come cheap. The Southern African Large Telescope in Sutherland, the largest telescope in the southern hemisphere, cost government and other investors about US$30m.
Meanwhile, much work remains for the SKA bid team.
SA has completed its studies into the troposphere - the lowest layer of the atmosphere, where most clouds and water vapour are located. In the dry Northern Cape, there is not enough water in the atmosphere to absorb and disturb radio waves at high frequencies.
And the ionosphere - the region of charged particles in the upper atmosphere which can disturb radio waves occurring at lower frequencies - is stable above SA.
Outstanding issues include the technology and costing details for the data network.
The SKA - which is really a supercomputer with eyes into the heavens - will produce and transmit more data than the rest of SA combined. "We will need a network capable of speeds of 4 Tbit/s from the core [8,4m times faster than Telkom's fastest ADSL broadband connection] and 100 Gbit/s from the outlying areas [200 000 times faster than Telkom's best ]," says Fanaroff.
Exactly how this will be achieved has not been decided. What is certain is that cost will count. Data transmission tariffs will be one of the biggest costs in the SKA. An interesting example is the European Union's Géant network. In this case a consortium of partners built a network backbone capable of gigabit speeds to meet the research needs of 26 national research and education networks across Europe.
Today the network is connected to countries around the world - including, in the near future, SA. "Part of the capacity in some of the countries is used by commercial customers, which subsidise the costs of the research institutions," says Fanaroff.
Another outstanding worry is that of preserving radio quietness around the core of the SKA as well as the many small antennas that will make up the receiving surface of the telescope.
The SKA, if it is built in Southern Africa, will have its core in the Northern Cape and stations in Botswana, Madagascar, Mauritius, Mozambique, Namibia, Kenya and Ghana.
In each of these countries the antennas will have to be sheltered from radio interference. "The SKA uses frequencies that extend beyond the spectrum explicitly reserved by the International Telecommunications Union for radio astronomy."
The SKA project team has been in discussions with SA's own regulator, Icasa, as well as those of the neighbouring countries. The Australian team recently made a significant move when its regulator issued a moratorium on new transmissions in the zone around their proposed site.
SA is still talking to Icasa to find ways to create a radio quiet zone around the core of the telescope, which is the most sensitive to radio interference.
In April the international SKA site spectrum monitoring team arrived in SA to conduct radio frequency interference studies at the core site . These confirmed the SA site as a very quiet area for radio interference. The team must now study China, Australia and Argentina.
As the December deadline looms, the KAT project team will continue working on new prototypes for digital receiver technology, digital beam-formers and low-cost designs for the telescope dishes.
SA's increasingly visible prowess in the space science industry has also resulted in a number of foreign institutions expressing an interest in building their own infrastructure here.
By Sasha Planting
SA is making progress in its bid for a euro 1bn global space project
No comments:
Post a Comment