• Sansa’s advanced tracking systems are integrated into an international network, and have been relaying real-time data to NASA during Artemis II’s mission-critical moments.
• South Africa’s space tracking history dates back to 1963, supporting Apollo-era missions, and continues today with cutting-edge technology and international partnerships.
• Sansa is expanding its infrastructure, including a new ground station in Matjiesfontein, aiming to strengthen South Africa’s role in the global deep-space network.

While a spacecraft carrying the ambitions of a new lunar era tore back through Earth’s atmosphere on Saturday, attention was fixed on the unforgiving choreography of re-entry — a phase where the margin for error narrows to almost nothing.

For South Africa, the moment carried a weight of responsibility as thousands of kilometres away in Hartebeesthoek, Pretoria, its antennas and engineers were part of the effort to bring it home safely.

The mission in focus was Artemis II — NASA’s first crewed return to the Moon since the Apollo 17 mission. The capsule’s splashdown unfolded on Saturday.

At the centre of South Africa’s contribution is the South African National Space Agency (Sansa), whose ground-based tracking systems form part of a global network monitoring spacecraft as they move between Earth and deep space.

Raoul Rogers, Sansa’s executive director for space operations, said the agency’s role was deceptively simple in description but exacting in execution.

“You track, you listen, and you make sure the spacecraft is where it’s supposed to be,” he said.

South Africa’s involvement in space tracking predates democracy. Rogers said the country’s relationship with NASA stretched back to 1963, when a tracking station operated locally as part of the United States’ early space programme.

He said the facility supported missions during the Apollo era — including the Apollo 11 Moon landing — before it was handed over to local control in the 1970s. Over time, the capability moved through various institutions before consolidating into Sansa, established in 2011.

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What has shifted since then is not South Africa’s presence in space operations, but the sophistication of the technology underpinning it.

He explained that while the Apollo-era missions relied on slower computers and manual processes, modern programmes like Artemis were driven by automation, high-speed data transfer and advanced antenna systems.

“You put the antenna on it and it will track it until it doesn’t see it anymore,” Rogers said.

He explained that the efficiency of modern systems did not reduce the stakes, but, instead, that the presence of astronauts raised the consequences of failure.

“Specifically when you have humans on board, then it becomes critical. The life of astronauts is key,” he said.

Rogers explained that every space mission relied on what engineers term a tracking network — a distributed system of ground stations positioned along a spacecraft’s trajectory. These stations communicate with the vehicle, monitor its movement and relay data back to mission control.

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Sansa’s facilities, among the largest on the continent, are integrated into this network through international partnerships. For Artemis II, Rogers said the agency was working through a third-party contractor that fed data into NASA’s systems in real time.

“We always work in real time with international partners. The information we collect is passed on immediately,” he said.

He said this arrangement reflected the global nature of modern spaceflight and that no single country could maintain uninterrupted contact with a spacecraft throughout its journey. Instead, agencies relied on a chain of ground stations spread across the world, each taking over tracking duties as the spacecraft moves in and out of range.

Sansa’s work is therefore time-bound and has to be precise. Its antennas lock onto the spacecraft during designated windows, gathering data before handing over to the next station in the network.

Those windows become critical during key phases of a mission — including trajectory changes, system separations and, most notably, re-entry.

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“There are certain manoeuvres where you need absolute certainty about where that spacecraft is. That’s when multiple stations are often used at the same time, with backups in place,” Rogers said.

He said re-entry remained the most dangerous phase of any mission. As the spacecraft descends through the atmosphere, it must enter at a precise angle. If it is too steep, it risks burning up. If it is too shallow, it could skip off the atmosphere and back into space.

Rogers said ranging data and Doppler measurements allowed engineers to calculate the spacecraft’s position and velocity with precision, informing decisions about when to initiate re-entry and where the capsule will land.

“It tells me where that spacecraft is and how fast it’s moving. That determines whether it’s safe to bring it into the atmosphere and where it will splash down,” he said.

On Saturday, those calculations were tested in real time as the Artemis II capsule made its descent, with human lives at stake.

Despite its capabilities, Sansa does not yet operate at the scale of NASA’s Deep Space Network, whose larger antennas can detect signals from far deeper in space.

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Sansa’s smaller, roughly 12-metre antennas are more limited in range and data throughput.

“The bigger your ears, the more you can hear at a further distance,” Rogers said.

But that limitation forms part of a longer-term strategy. The agency is expanding its infrastructure, including through plans for a new ground station in Matjiesfontein, aimed at positioning South Africa within the global deep-space network.

“If we have the facilities, the opportunities will arrive,” Rogers said.

He added that participation in Artemis II carried both technical and symbolic significance.

“It’s everybody’s dream to be part of the space race. South Africa has been part of it since 1963,” he said.

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