The last of the 64 foundations for the dishes for South Africa’s MeerKAT radio telescope array was poured on February 11, SKA South Africa (SKA SA) recently announced. The 64-dish MeerKAT will be a precursor to the international Square Kilometre Array (SKA) radio telescope, which will be jointly hosted by South Africa and Australia.
“The foundations were constructed to stringent specifications to ensure that the antennas will be exceptionally stable,” explained SKA SA GM: Infrastructure and Site Operations Tracy Cheetham. “Even at wind gusts of up to 69 km/h, scientists must be able to point the dishes at distant celestial objects in an exact manner and the antennas must be able to survive wind speeds of up to 144 km/h.”
As a consequence, each foundation is composed of eight steel-reinforced concrete piles, which extend from 5 m to 10 m deep, depending on soil conditions, plus a 5.2 m × 5.2 m slab of concrete positioned on top of the piles to add stability. For each foundation, 32 holding-down bolts were preassembled to form a circular steel cage, known as a bird’s nest, into which the concrete was poured. The construction of the foundations used more than 570 t of steel and nearly 5 000 m3 of concrete. The laying of the foundations took nine months.
“The completion of the foundations and the soon-to-be-completed first antenna represents a major milestone for the building of the MeerKAT, which will become an integral part of the SKA project,” said Science and Technology Minister Derek Hanekom. “I am very pleased with the progress and the quality of the work that our scientists and engineers are delivering on this challenging assignment and wish them well with the enormous task ahead of meeting the tight schedule in the next two years.”
“We are on the last leg now,” affirmed Cheet- ham. The Karoo Array Processing Building (KAPB) and the power facility are both receiving their final touches. The KAPB will house all the MeerKAT’s data processing racks and its power and backup equipment. The building is actually an underground bunker, shielded from radio frequency interference. The fibre-optic cable ducting has been completed, leaving contractor Plessey with the task of just pulling through and connecting the cable. All MeerKAT infrastructure should be completed by the end of next month.
For the next two months, the focus will be on testing that all the infrastructure operates to specification. This will include cold and hot commissioning. “During cold commissioning, the power is connected without switching on the equipment,” she elucidated. “During hot commissioning, the machines are turned on and tested for a period of time.”
SKA SA is the local organisation responsible for South Africa’s contribution to the global SKA project. The SKA is going to be the biggest, most sensitive radio telescope ever built. Phase 1 of the instrument will be composed of a midfrequency dish array in South Africa and low-frequency aperture arrays and a dish survey instrument in Australia. The SKA project is overseen by the SKA Organisation, which is a not-for-profit private company under UK law, based at the world-renowned Jodrell Bank Observatory, in Cheshire, England, not far from Manchester.
The budget for the construction of Phase 1 of the SKA has been capped by the board of the SKA Organisation at €650-million. This figure is the capital expenditure for the construction of the instrument, and excludes the design costs and the operating costs. Phase 2 will cost considerably more. Construction of Phase 1 is scheduled to start in 2018, with scientific commissioning and start of operations in 2020.