The international engineering consortium tasked with planning the assembly, integration and verification (AIV) of the Square Kilometre Array (SKA) radio telescope has formally completed its work, another crucial step towards the construction of the world's largest radio telescope.

The AIV consortium, formed in 2013, was led by the South African Radio Astronomy Observatory (SARAO), and was responsible for delivering the AIV process for SKA's mid-frequency array (SKA-MID) in SA and the low-frequency array (SKA-LOW) in Australia.

SKA is a radio telescope project proposed to be built in SA and Australia. If built, it would have a total collecting area of approximately one square kilometre.

Processing the vast quantities of data produced by the SKA will require very high-performance central supercomputers capable of in excess of 100 petaflops (one hundred thousand million million floating point operations per second) of raw processing power.

According to SARAO, the experience gained, and lessons learnt, by the South African engineers, from designing the AIV process for MeerKAT, positioned the organisation as the natural lead for the AIV consortium.

SARAO engineers, as well as engineers from Australia's Commonwealth Scientific and Industrial Research Organisation and the Netherlands Institute for Radio Astronomy constituted the SKA AIV consortium.

"The AIV programme is critical to ensure that telescope elements that have been designed and built by a dispersed global community, are tested, assembled and verified in a rational and thorough way, thereby ensuring that the entire telescope system will work as designed, to budget and on schedule," says Professor Justin Jonas, chief technologist at SARAO.

SARAO says experience with other radio telescopes has demonstrated that the roll-out activities are often underestimated, resulting in delays in deployment, due to re-engineering and retrofitting of components, which in turn increases the total cost of the system.

It points out that many issues that are discovered during "downstream" integration and verification are the result of "upstream" neglect.

The sheer scale and complexity of the SKA, therefore, made it essential that AIV planning was done at an early stage, in parallel with the work of the element-design consortia, it adds.

"SKA-MID will consist of nearly 200 dishes in South Africa and 130 000 antennas in Western Australia, so we don't want to assemble and integrate and then discover something crucial is missing, or doesn't work as we expected it to," says Richard Lord, AIV consortium lead at SARAO.

"We've learned valuable lessons from MeerKAT about how challenging AIV can be if issues are identified too late during deployment. Planning for the AIV now gives us the best possible preparation for accurate procurement and construction for the SKA."

The work completed by the AIV consortium will be included in the overall System Critical Design Review (CDR) for the SKA, scheduled for later this year, which will ensure that all the different design elements of the SKA align with each other.

"This small consortium has moved mountains in terms of the amount of preparation done for both SKA telescopes I want to sincerely thank them for their efforts," says Peter Hekman, engineering project manager responsible for AIV at the SKA headquarters.

"After System CDR, their work will really begin to pay dividends, as we put these plans into action with the construction of the SKA."

SARAO managing director, Dr Rob Adam, also thanked and commended the SKA AIV Consortium: "I want to congratulate Richard Lord, and the AIV consortium, for their exemplary work, on what is an extremely challenging aspect of the SKA design work, and I am very proud of the contribution of the SARAO system engineers."