The Square Kilometre Array telescope is likely to be redesigned following a major miscalculation of the project’s costs.
The SKA Organisation discovered in December 2016 that the total project was likely to cost €916 million (£778m) rather than the forecasted €674m, Research Fortnight has learned.
As a result, since the start of 2017, the project has been undergoing a cost-control exercise instigated by South Africa and Australia, two of the 10 countries that form the SKA Organisation.
The construction of what is expected to be the world’s largest radio telescope is due to begin in 2018.
Philip Diamond, director-general of the SKA Organisation, told Research Fortnight that, since December, the consortium had managed to reduce the shortfall by about €90m and total costs were estimated to reach €828m—a figure that he expects to be further reduced.
“It is not that the costs were underestimated,” Diamond said. “Nobody has done anything like the SKA before and so we had our initial cost estimates from a design consortia in 2013, and those were the best estimates that we had without the engineers having done any detailed design work. When you do that work, you discover the complexity of the problem.”
A SKA document seen by Research Fortnight lists 36 potential changes to the original design that would reduce costs. These options are ranked according to their impact on the science that the telescope is expected to deliver.
The list includes minor tweaks, such as: powering some of the project’s dishes from solar energy, which would remove the need for overhead power lines; simplifying the science data network connecting the antenna stations to the central signal processor, the telescope’s main processing brain; and reducing the amount of high-performance computing available to process raw data.
Another option with a bigger impact on the science would be to reduce the amount of process bandwidth, which would increase the time taken to make observations.
The most drastic options include: reducing the number of dishes from 70 to 59 in South Africa, which would reduce the telescope’s sensitivity by 20 per cent; removing 54 stations from the core area of the project in Australia; and reducing band time.
Cutting band time is one of the most controversial ideas, as it could mean that some of the projected science, such as the study of planetary disks or star formation, cannot be carried out until extra funds have been found.
Meanwhile, South Africa is understood to be pushing for scaling up the technology at the existing MeerKAT radio telescope and the Murchison Widefield Array (MWA) radio telescope in Western Australia, both of which are located in the same sites where the SKA will be built, eliminating the need for new designs.
Diamond added that he was optimistic about welcoming new countries into the SKA Organisation, and is holding conversations with the governments of Portugal, Spain, France, Germany, Switzerland, Japan and South Korea. The German government, which pulled out of SKA in 2014, is still considering a proposal to fund its participation in the SKA, which was put forward in January 2016 by a consortium of 35 research institutions led by the Max Planck Institute.
Some of these countries, Diamond said, would like to wait until the SKA Organisation becomes an intergovernmental body before joining. A convention paving the way for such a body is likely to be signed in July. However, such a deal must then be ratified by each of the current countries in a process that could take up to 12 months to be finished. The SKA Organisation is so far made up of Australia, Canada, China, India, Italy, New Zealand, South Africa, Sweden, the Netherlands and the UK.
Nichi D’Amico, president of the Italian National Institute for Astrophysics, said he did not consider the situation to be dramatic. “Our first goal is to establish the SKA intergovernmental organisation and ensuring that the minimal configuration of the project can produce good science, and is scientifically appealing and convincing in terms of costs,” he said. “The advantage of SKA is that it is easily scalable. As soon as the budget increases, the telescope can grow.”
Jonathan Pritchard, senior lecturer in astrostatistics at Imperial College London, who chairs the SKA Epoch of Reionization science working group, said that although considering reductions was painful, the exercise “feels like a healthy part of going from a design that is maybe still slightly speculative to something that is really concrete and affordable”.
“It is normal when you are designing a new telescope that there are uncertainties about how much new technology would cost,” he said.
The project’s science working groups will discuss these options at a town hall meeting on 18 and 19 May in Manchester. The board of the SKA Organisation will aim to make a decision at a meeting in July.
This article also appeared in Research Fortnight‘s 500th issue, guest edited by Andre Geim. A version of this article also appeared in Research Europe.