The construction of a radio telescope that will look for the first stars in the universe, is making headway near Carnarvon, in the Northern Cape.
It is also making waves for the way it has involved the local community and boosted the local economy.
A construction team of 24 people on site and another three in Cape Town are working on the Hydrogen Epoch of Reionisation Array (Hera) project.
About one-third of the 350 14-m-diameter dishes for the radio telescope have been built so far, Hera project engineer Kathryn Rosie tells Engineering News Online.
Hera forms part of the wider Square Kilometre Array (SKA) and will look at the first period after the Big Bang.
The innovative Hera radio telescope will be instrumental in detecting the distinctive signature that will enable astronomers to understand the formation and evolution of the very first luminous sources – the first stars and galaxies in the Universe. This is a period scientists call the Epoch of Reionisation.
Rosie explains that the low-frequency instrument needs only a simple construction, as it only has one goal in mind.
“The instrument itself needs to do only one thing – to look at the period in our history when the first stars in our galaxy lit up. They think they know where to look. Because it doesn’t have to do a range of things and low frequencies can get away with lower tolerances, we are able to have a low-cost, efficient construction.”
Hera comprises a close-packed array of fixed parabolic reflector elements or dishes. The instrument is largely constructed from surprisingly simple materials including meranti wood, polyvinylchloride (PVC) pool pipe and chicken mesh, with all the materials and labour sourced in South Africa, mostly in the Karoo.
“We’ve been able to source material locally and hire people from the community, many of whom don’t have a tertiary education. They’ve been able to learn on the job and be part of this very exciting project. It’s been so heartening to see,” says SKA South Africa head of communication and stakeholder relations Lorenzo Raynard.
SKA South Africa senior astronomer working on Hera, Dr Gianni Bernardi, explains that the centre piece of each dish is determined by the placement of a concrete hub. These hubs constrain radial PVC spars, tensioned into approximate parabolas against a rim, which is supported by telephone poles. Welded mesh panels are installed on the spars to form the reflector surface.
Lorenzo sees the US’s investment in Hera as a strong indication of confidence in the overall SKA project.
“While the US is not yet part of the SKA, it’s been rewarding to see how our exciting infrastructure projects in South Africa are attracting interest indirectly from the US.”
Last year, the Hera project was awarded a $5.8-million grant by the Gordon and Betty Moore Foundation in the US. This supplemented an earlier $9.5-million investment by the US-based National Science Foundation.
The funding by the Gordon and Betty Foundation enabled 110 dishes to be added to the project, which will increase the sensitivity of Hera.
The Hera collaboration includes Arizona State University, Brown University, Cambridge University, the Massachusetts Institute of Technology, the National Radio Astronomy Observatory, Scuola Normale Superiore, Square Kilometre Array South Africa, University of California at Berkeley, the University of California at Los Angeles, the University of Pennsylvania and the University of Washington.
The participating South African universities include Rhodes University, the University of KwaZulu-Natal, the University of the Western Cape and the University of the Witwatersrand.