PICS: SKA dish construction edges forward in SA

Simnikiwe Mzekandaba
By Simnikiwe Mzekandaba, IT in government editor
Johannesburg, 10 Jul 2024
Telescope construction is progressing in the Northern Cape as the first SKA-Mid dish is set up. (Photograph by SKA Observatory
Telescope construction is progressing in the Northern Cape as the first SKA-Mid dish is set up. (Photograph by SKA Observatory

The first Square Kilometre Array (SKA)-Mid telescope dish has been assembled in SA’s Northern Cape province, says the SKA Observatory (SKAO).

This marks another key construction milestone towards bringing the mega science project to fruition.

More than 10 years in the making, the SKA project is an international effort to build the world’s largest radio telescope. South Africa and Australia are joint project hosts.

Last week marked the completion of the first of four dishes that will comprise the first stage of SKA-Mid delivery, known as Array Assembly 0.5 (AA0.5), reveals the SKAO. It will allow for testing and a process review to take place prior to full-scale dish production.

In total, there will be 197 SKA-Mid dishes, stretching across 150km in the Northern Cape, and covering a wide frequency range, from 350MHz to 15.4GHz, with a goal of up to 24GHz in the future.

These dishes can operate as a whole or as sub-arrays, and will enable a wide range of science, from studying transient events such as fast radio bursts, to making detailed studies of the gas distribution within galaxies and detecting the complex organic molecules that can form the building blocks of life.

Photograph by SKA Observatory.
Photograph by SKA Observatory.

Over the past year, construction activity has accelerated at both of the SKAO’s telescope sites. March saw the rollout of the first SKA-Low telescope antennas in Western Australia.

Last week’s “big lift” of the 15m-wide main reflector onto the telescope pedestal was performed by a team from the SKAO, the South African Radio Astronomy Observatory (SARAO) and China’s 54th Institute of China Electronics Technology Group Corporation (CETC54), which is manufacturing the dishes.

“The progress this year across the observatory has been amazing, and seeing the first SKA-Mid dish being erected is a significant moment as we head towards the first stage of telescope delivery,” says SKAO acting director of programmes Luca Stringhetti.

“There have been challenges, as we anticipated there would be, but it is thanks to the co-ordinated effort and support of our partners across the globe, combined with significant logistical work by teams at the telescope sites and our headquarters, that we have been able to deploy the first dish structure and four stations on the ground in both of our telescope host countries.”

“CETC54 is excited and deeply proud to be part of installing the first SKA-Mid dish in South Africa, which is set to operate for over 50 years. Since its conception, the SKA project has embodied the collective aspirations and efforts of many institutions in the pursuit of cosmic exploration,” adds Wang Dawei, SKA-Mid dish project manager at CETC54.

“The precise installation of the main reflector is just the first step, and we will continue to implement high-precision measurement adjustments and accurate calibration on the antennas, in order to deliver the dishes to the SKAO’s exacting quality standards.”

Photograph by SKA Observatory.
Photograph by SKA Observatory.

The SKA Observatory highlights that the SKA telescopes (in SA and Australia) are being rolled out in a phased manner.

This strategy, it states, means the SKAO can deliver the most effective instruments possible at each stage, leading towards the full realisation of the observatory and managing the wide range of challenges encountered along the way.

“As a team, we are now totally focused on the next stage of activities because we have already got two more dish structures on site, ready for assembly,” explains SKA-Mid site construction director Tracy Cheetham. “This is a complex environment, with many variables, but we are in a strong position to proceed with the next steps towards AA0.5.”

Other SKA-Mid components are being manufactured across other SKAO partner countries, including Italy, Spain, Sweden, the UK and SA, where Stellenbosch-based EMSS Antennas, provider of highly-sensitive, cryogenically cooled receivers (or feeds), was awarded the construction contract for SKA-Mid’s band 2 receiver.

The next phase for the first SKA-Mid dish will be to install the huge feed indexer, which will position the receivers into place, depending on the observation being undertaken.

“There’s a lot of work ahead of us, but for everyone involved, this is a special moment that represents years of toil by people all over the world, so I want to thank them for their dedication in getting us here. Special thanks must go to our partners at SARAO and CETC54 for their professionalism and commitment − this collaboration is really bearing fruit,” states SKA-Mid senior project manager Ben Lewis.

“The first of anything is always the most challenging, and we have learnt a huge amount from a logistical and technical perspective from this first dish. That will inform our planning going forward as we prepare to deliver a four-dish array early next year, before ramping up to full speed construction later in 2025.”

Photograph by SKA Observatory.
Photograph by SKA Observatory.