Last updated March 9, 2017 at 8:54 am
In Stellenbosch, a beautiful winelands region just outside Cape Town in South Africa, more than 250 engineers and scientists from 18 countries have gathered to discuss progress on the world’s most powerful radio telescope, the Square Kilometre Array, or SKA.
It’s the 2016 annual SKA Engineering meeting – and these engineers and scientists aren’t even half the team. Altogether, there are 600 hundred of us, from 20 countries.
What is the SKA?
With thousands of radio receivers spread over thousands of kilometres of desert in South Africa and Western Australia, the SKA will be the largest scientific facility in the world. It is designed to answer fundamental questions about the evolution of the universe, the origin of the first stars and galaxies, where we came from, are we alone in the cosmos or is there somebody else out there. So if the SKA is spread over kilometres, and over continents separated by oceans, why do we call it the ‘Square Kilometre Array’? It’s because the sum of the area of all the dishes in the telescope will add up to one square kilometre.
To make this vision a reality, the dedicated horde of scientists and engineers has spent years, decades even, designing a telescope vastly superior to its predecessors. It will have a sensitivity and resolution that will let us peer into the deepest reaches of the universe. But building such a vast and powerful telescope is a long process and there are many challenges.
The idea
The idea of building such an enormous telescope is not new. The basic concept has been around since the mid-20th century, but it was in the early 1990s that the push to undertake the project began to gain serious momentum. Astronomers realised that if they were to push the frontiers of knowledge further into the most distant corners of the universe to study the cosmos in greater detail, they needed a telescope that would cost more than any one country’s scientific community could afford.
Nations were going to have to be persuaded to get together and pool their resources. The world’s astronomers found the argument very persuasive, and in 1993 the International Union of Radio Science established the Large Telescope Working Group to begin to develop the scientific goals and technical specifications for what would become the SKA.
SKA Organisation
A not-for-profit company, the SKA Organization, was formed to coordinate the efforts of the international members of the telescope project. And coordination is essential, because the SKA is so complex that no one person can understand, in detail, all of the systems that make the telescope work.
To break the vast project down into manageable chunks, 11 consortia were established, each responsible for developing separate components of the telescope, such as the receivers, the data links, or the processing facilities. This is a typical practice with projects of this scale, and enterprises such as the Large Hadron Collider and many space craft have been designed and built this way.
The annual engineering meeting, this year held in Stellenbosch, is where all of the consortia meet to discuss problems and progress, and how it will all fit together.
Solving big problems… literally
The SKA project draws on the expertise of dozens of research institutes, many of which, like CSIRO, have been involved in radio astronomy since its birth in the 1940s. Despite this valuable expertise, the scale of the SKA creates engineering problems that no other telescope has had to face.
- The huge number of antennas means we must find a cheaper way to build radio dishes without sacrificing manufacturing precision.
- New, custom radio receivers have been designed.
- Thousands of kilometres of road, power cables, and data links need to be laid.
- And how do you power such an energy-hungry facility, hundreds of kilometres out in the remote desert?
CSIRO’s Australian SKA Pathfinder telescope in Western Australia is now 40% solar powered, making it the first observatory in the world to use renewable energy. Highly energy-efficient processors are being developed to help reduce the telescope’s large demand for power.
One of the greatest challenges has been planning how to handle the huge volumes of data that the telescope will generate. Once fully operational, the SKA will produce 100 times more data than the entire Internet! Lots of time, thought and effort are being invested into developing processors and software capable of dealing with the anticipated flood of data.
You want blueprints? Here’s a *small* fraction of blueprints at the Engineering meeting.
To help overcome the astonishing challenges facing the SKA, several prototype telescopes have been designed and built around the world to test and refine systems that will be employed in the final SKA. A few of these prototypes, the ‘precursor’ telescopes, will be absorbed into the future SKA once full construction gets underway. These telescopes include:
- ASKAP — the Australian SKA Pathfinder. ASKAP is an array of 36 radio dishes built by CSIRO in outback Western Australia. It is designed to test innovative technologies, including CSIRO’s ‘phase-array feeds’, which is a new receiver technology designed to scan large areas of the sky very quickly.
- MWA — the Murchison Widefield Array. Built next to ASKAP, MWA is an array of thousands of small antennas sensitive enough to observe the earliest stars and galaxies in the universe.
- MeerKAT — a large array of radio dishes in South Africa that uses more conventional radio-telescope technologies. When completed, it will be the most sensitive telescope of its kind, to be surpassed only once it is absorbed into the SKA.
The precursor arrays are outstanding telescopes in their own right and are already spawning new scientific discoveries. Together, they give tantalising glimpses of the astounding images and science that the SKA will deliver.
To the telescope’s engineers and scientists, the Stellenbosch meeting has been a showcase of the enormous efforts and progress that have been made, and the exciting science that is already pouring out of the precursor telescopes. But we are also very aware that there is still a lot of work to do to finalise the telescope’s design in time for construction to begin at full speed in 2018.
Written by David Gozzard
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