Engineering the Square Kilometre Array

The largest, most powerful telescope ever conceived – the Square Kilometre Array (SKA), is going to have over a hundred thousand radiotelescopes spread across Australia and South Africa. Its purpose – to look further out into the universe, and further back in time, than any telescope before.

It is, quite simply, the biggest astronomy project ever devised.

However, when it turns on it’s going to require a massive amount of supporting equipment just to operate.

From roads, buildings and power, to shielding from radio interference and supercomputing facilities, the engineering challenge is as massive as the scientific one.

Now, the plans for all that supporting equipment, drawn up by the CSIRO and their Australian engineering partner Aurecon, have been approved for the Australian sites.

Monumental projects need monumental solutions

“We’re setting the groundwork to host 132,000 low-frequency SKA antennas in Australia. These will receive staggering amounts of data,” CSIRO’s SKA Infrastructure Consortium Director, Antony Schinckel said.

“The data flows will be on the scale of petabits, or a million billion bits, per second – more than the global internet rate today, all flowing into a single building in the Murchison.

“To get this data from the antennas to the telescope’s custom supercomputing facilities we need to lay 65,000 fibre optic cables.”

The scale of the SKA is beyond anything built before. Those 132,000 antennas will be spread over 2000 square kilometres of the Western Australian outback. Those antennas then need to be linked together by hundreds of kilometres of fibre-optic and power cables.

According to the engineers, the antennas themselves don’t draw much power, but the cables that run to them do. And that turned conventional thinking on its head, with the team needing to think outside the box.

One solution is that most remote antennas will have their own solar-power systems.

Cutting interference from itself

Another major challenge was protecting the infrastructure from any radio-frequency interference.

While the Australian site has been specially created and protected by law to minimise the chance of interference, it still won’t be silent enough for the astronomers.

With all electrical equipment making radio waves that are millions or even billions of times stronger than ones from the cosmos, the equipment will need to essentially protected from itself. To achieve this, the CSIRO has needed to design unique shielding that keeps these man-made signals away from the telescope’s ultra-sensitive antennas so they don’t contaminate the data being recorded from space.

“Containing the interference created by our own computing and power systems is an unusual construction requirement,” says Shandip Abeywickrema from Aurecon.

“We’re trying to reduce the level of radio emissions by factors of billions.”

One of the challenges was the gigantic supercomputing facility needed to process the data onsite.

“The custom supercomputing building is effectively a fully welded box within a box, with the computing equipment to be located within the inner shield, while support plant equipment will be located in the outer shield,” says Abeywickrema.

The unique engineering challenges created by a project like the SKA provide engineers a chance to approach problems in all new ways. This, in turn, creates solutions that may filter down to everyday engineering in the future.

With construction beginning in 2020, it’s likely that more creative solutions will be required yet.

This article was first published on Australia’s Science Channel, the original news platform of The Royal Institution of Australia.

Related reading: SKA: Tooling up down under for the world’s most powerful telescope