It was a well-fought battle. Contenders South Africa and Australia each undertook a tremendous nine-year campaign to host the internationally funded Square Kilometre Array (SKA) — a telescope comprising thousands of dishes with a collecting area spanning a square kilometre1. Before the decision in late May, both countries had even started developing precursor facilities, in what might be interpreted as attempts to better their odds.

And the result? Both proposals will be used, in a dual-site plan that will stretch the budget — and the possibilities — of the endeavour. The eight African countries partnering South Africa's bid will support development of a mid-frequency (200–500 MHz) array, optimized to investigate the nature of gravity. The Australasian effort will probe the history and composition of the universe (including dark matter and dark energy) by fielding the low-frequency (70–200 MHz) range, and surveying hundreds of millions of galaxies. The split approach capitalizes on the existing investments of each nation, and plays to the sites' individual strengths.

The decision was, however, met with disappointment in South Africa, widely held as favourite to host the entire array. Minister of Science and Technology Naledi Pandor issued a statement2 pointing out that an independent committee had deemed the African site the better option, and suggesting that the decision was motivated by a desire “to be inclusive”.

Indeed, a report compiled by experts forming the SKA Site Advisory Committee (SSAC) identifies South Africa as the preferred site3. Many proponents of Australia's bid had hoped that the nation's wealth and stability might tip the scales in their favour. But the SSAC report attributed 75% of determining factors to scientific and technical concerns, and only 2% to political and socio-economic issues.

Although it seems that a dual-site option was initially explored in the spirit of diplomacy, the process made clear the scientific advantages associated with the split. The project's myriad scientific goals4 demand a frequency range that was always going to require construction of more than one type of antenna. The decision to isolate these technologies diminishes the chance that the planned survey component of the project will compromise SKA's mid-frequency ambitions.

Much has been made of the economic implications of the dual-site plan in the wake of its announcement. And it's clear that having two sites will increase the cost of the SKA — but that may be a reasonable trade for what should be a scientific (and diplomatic) triumph.