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SA telescope engineers submerge computers in oil to protect them from the sweltering Karoo heat

Sarah Wild , Business Insider SA
 Mar 21, 2020, 09:00 AM
A composite image from the South African Radio Astronomy Observatory.
  • Radio telescopes are located in some of the most extreme environments on Earth, and their hardware systems need to survive the elements.
  • IronHive, developed as part of SA’s giant MeerKAT telescope, is a collection of computer processors, each the size of a credit card, encased in an oil-filled container.
  • This is one of a number of technologies that South Africa’s radio astronomy observatory is looking to commercialise.
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In the middle of summer, the temperatures at South Africa’s radio astronomy site in the Karoo loiter above 30 degrees Celsius, but can drop to below freezing in Winter.

But the computers that process the telescope’s huge quantities of data need to be kept at a relatively stable temperature, while being far away from power sources. 

Most radio telescopes sites are in remote areas because they need to be far away from people and their technologies, which disrupt the relatively weak radio signals coming from other celestial objects in the universe. 

This is why South Africa’s telescope engineers designed Ironhive, a super-computer encased in an oil-filled stainless steel container. 

“Individual computing elements are getting very powerful and cheap,” says Simon Ratcliffe, the technical lead for scientific computing at the South African Radio Astronomy Observatory. It is possible to buy complete computers that are the size of credit cards, and connect these together to deliver massive computing power. 

Ironhive contains hundreds of these mini-computers, packaged in such a way that “we don’t have to build a traditional data centre”, explains Ratcliffe.  

Computers produce a lot of heat, and so cooling is an important part of traditional data centres.

 “In a normal data centre, a substantial part of both the capital and ongoing operational costs relate to the cooling system”, he says. In such a remote site these costs can become impractical. 

For Ironhive, they used a technique called“immersion cooling”.

“We made a big stainless-steel container, filled it with mineral oil, and dumped in a computer”, he says. Electric current does not flow in this special oil, and the heat capacity is thousands of times the heat capacity of air, he says. Also, removing heat from oil is “easy” – something which all car radiators are able to do. 

“Because it is in a sealed box, it is immune to the environment – there’s no air flow, no dust. You can put it on a block of concrete on the ground,” he says. While the observatory has use for Ironhive internally, they are also eyeing its possible uses in satellite ground stations across the continent. “It’s a way of parachuting in a sealed, high-performance computing unit that does not need large scale-infrastructure,” he says. 

Ironhive is one of a number of inventions patented by the SARAO team, which often needs novel solutions to its radio astronomy problems. For example, its engineers, in conjunction with local companies, developed Comrad, a passive radar solution to detect aircraft passing over head. 

South Africa’s 64-dish MeerKAT telescope “is a system that ingests, processes, stores, and analyses data”, says Pontsho Maruping, head of commercialisation at SARAO. “Through that value chain of receiving, transmitting, storing and analysing data, we’ve had to develop some innovative tools that help us with doing all of those things.”

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