Rushelle Baartman is still counting her lucky stars — all 200 billion trillion of them.
From sitting unemployed in her parents’ house in Carnarvon, she now works at a famous radio astronomy site helping scientists figure out some of the biggest questions of all time: where are we? And how long have we been here?
Having grown up under one of the world’s starriest skies, she is now exploring it.
Baartman, 28, is one of 10 permanent staff from the small Northern Cape town who built the HERA radio telescope — and who maintain it. For the past seven years, she and her team have been building 350 carefully calibrated wire-mesh telescope dishes, pointed right at the centre of the Milky Way.
The dishes are home-grown and proudly South African, dependent on the labour of local artisans. Most of them are already in use, but about 100 are still being commissioned, with all of them expected to be done before the next summer stargazing season.
Many of us didn’t have work before, but for seven years now we’ve been able to put food on the table.
— Rushelle Baartman
“I’m very curious, and here I’m always learning something new,” Baartman said from the telescope site outside town. “Many of us didn’t have work before, but for seven years now we’ve been able to put food on the table.”
The Hydrogen Epoch of Ionisation Array (HERA) is a US-led project, funded by the University of California, Berkeley, which also involves institutions from Europe, South Africa and UK. The aim is to provide a 3D map of the universe at the dawn of time.
It was designed to pick up low-frequency radio waves of the kind prevalent before the birth of stars, galaxies and black holes. For this reason it has distinctive wire-mesh dishes which can pick up longer low-frequency radio waves, whereas solid dishes — such as the enormous white dishes of other radio telescopes — are required to pick up shorter frequencies.
HERA forms part of the family of radio telescopes in the Karoo “star belt” which include the better-known MeerKAT radio telescope, a precursor to the Square Kilometre Array.
Construction of the HERA dishes began in 2015 and provided a much-needed cash injection for Carnarvon, a Central Karoo town with two service stations and one grocery store — among a shortlist of potential employers. “It’s a majority sheep farming area and the prospects of finding a job are not good,” explained HERA project manager Ziyaad Halday, who commutes to the area along with other radio astronomer stakeholders on an Execujet flight for regular maintenance of the dishes.
“When the advert first went out to the town (for work on the project), I got about 200 applications, from which I employed an initial 20-person team all from Carnarvon for the first four or five years,” Halday said, adding that the team had since been scaled down. Though the project is due to close in 2026, it is hoped the staff will be absorbed into other work streams.
Overall, the HERA impact study provides clear evidence of the economic benefits of co-hosting astronomy instrumentation at the national and provincial level in South Africa that includes the direct benefits to the towns closest to the astronomy infrastructure site.
— SARAO report
He said the HERA site, being a radio quiet space and geared for radio astronomy, was well suited to host other scientific instruments.
Mathakane Molewa moved from Polokwane, Limpopo, to join the project team. As supervisor she oversees the ongoing work. “It was quite a drastic change to move here especially when you come from such a busy town. Things here are done quite differently,” she said of her new hometown, where she lives with a young child. The initial construction work involved multiple local contractors who supplied the materials needed to build the dishes, including the wire mesh, concrete and PVC poles. “The mesh came in a roll and had to be cut into smaller panels. You have to align them to the PVC poles and wooden superstructure,” she said. “It’s a bit like a puzzle where you have to fit things in.”
Survey work and instrument calibration were other key work components.
She said her team worked well to get the job done. “Some didn’t even have matric when I started working here and I needed to understand the background here. They were an amazing team and they were able to execute the job well.”
A SARAO impact study in 2021 confirmed HERA’s positive economic impact on Carnarvon and nearby Karoo towns:
- More than R15m in expenditure towards goods and services was made to suppliers in the Northern Cape during the construction of the instrument.
- Of that, Carnarvon received about 95% in DFI (development finance institutions) through spends during the construction period, made to local suppliers.
“Overall, the HERA impact study provides clear evidence of the economic benefits of co-hosting astronomy instrumentation at the national and provincial level in South Africa that includes the direct benefits to the towns closest to the astronomy infrastructure site,” said the SARAO report.
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