Michelle Jones
THE award of SKA to South Africa and Australia combined the best of two worlds – low costs in South Africa of electricity, labour and materials and Australia’s secure socio-economic and political environment.
This made for a low risk option for the hosting of the Square Kilometre Array (SKA) radio telescope. The SKA Organisation’s board of directors established the Site Options Working Group (SOWG) in April to investigate whether viable dual-site implementation options exist for the SKA and, if possible, present a preferred option.
It was announced 10 days ago that SA, partnered with eight other African countries, and Australia, paired with New Zealand, will share hosting of the world’s largest telescope.
“The board required that the preferred option should be capable of delivering the SKA science case while making best use of the existing investments and characteristics of both sites and being financially viable,” said the working group’s report.
SKA is to be built in two phases, the first largely based on the precursor arrays, South Africa’s MeerKAT and Australia’s SKA Pathfinder, and the second would see about 3 000 dishes dotted around South Africa, and other antennas built in Australia.
“A dual-site implementation, in which the two sites host different technologies operating at different frequencies, appears capable of delivering the SKA Phase 2 science case,” the report said. “There is no identified scientific advantage of a dual-site implementation for the SKA Phase 2 over a single-site implementation. For SKA Phase 1, incorporating the MeerKAT and ASKAP Precursors and related infrastructure offers a distinct scientific advantage.”
The working group noted that the total investment in the precursors which would then become available to the SKA project was in excess of R3.2 billion.
“However, a dual-site implementation for either SKA Phase 1 or Phase 2 introduces additional capital costs, as well as additional operating costs and programmatic risk.
“An important aspect of a dual-site implementation is the introduction of the concept of the ‘SKA Observatory’ – a single facility that may have multiple locations.”
The report said this facility could be in SA, Australia, New Zealand or elsewhere. SA had been recommended by the SKA Site Advisory Committee as the preffered host.
The working group noted that SA had an advantage over Australia in provision of power infrastructure and lower labour and material costs. The committee had also noted that with the exception of recurrent power costs the operation costs on the two sites were “virtually the same”.
The group noted that the committee’s report saw an advantage for SA in the four implementation plans and cost factors, while Australia and New Zealand were favoured in all of the six other selection factors, which were socio-economic and political considerations.
“A majority of the SOWG noted that a dual-site implementation for a SKA Observatory could potentially offer risk mitigation to the project across all 10 of these additional factors.”