The SKA Project
The Square Kilometre Array (SKA) project is an international effort to build the world’s largest radio telescope, with eventually over a square kilometre (one million square metres) of collecting area. The scale of the SKA represents a huge leap forward in both engineering and research & development towards building and delivering a unique instrument, with the detailed design and preparation now well under way. As one of the largest scientific endeavours in history, the SKA will bring together a wealth of the world’s finest scientists, engineers and policy makers to bring the project to fruition.
The SKA will eventually use thousands of dishes and up to a million low-frequency antennas that will enable astronomers to monitor the sky in unprecedented detail and survey the entire sky much faster than any system currently in existence.
Its unique configuration will give the SKA unrivalled scope in observations, largely exceeding the image resolution quality of the Hubble Space Telescope.
It will also have the ability to image huge areas of sky in parallel a feat which no survey telescope has ever achieved on this scale with this level of sensitivity. With a range of other large telescopes in the optical and infra-red being built and launched into space over the coming decades, the SKA will perfectly augment, complement and lead the way in scientific discovery.
Both South Africa’s Karoo region and Western Australia’s Murchison Shire were chosen as co-hosting locations for many scientific and technical reasons, from the atmospherics above the sites, through to the radio quietness, which comes from being some of the most remote locations on Earth.
South Africa’s Karoo will host the core of the high and mid frequency dishes, ultimately extending over the African continent. Australia’s Murchison Shire will host the low-frequency antennas.
A global effort
Whilst 14 member countries are the cornerstone of the SKA, around 100 organisations across about 20 countries are participating in the design and development of the SKA. World leading scientists and engineers are working on a system which will require two supercomputers each 25% more powerful than the best supercomputer in the world in 2019, and network technology that will see data flow at a rate 100,000 times faster than the projected global average broadband speed in 2022 (source: CISCO; November 2018).
The SKA is being developed over a phased timeline. Pre-construction development officially started in 2013 and has taken place over a period of seven years, involving the detailed engineering design and governance work needed to bring the SKA to construction readiness. Construction of the SKA is scheduled to begin in 2021, while routine science observations are expected to start in the late 2020s.
In Australia, the SKA’s low-frequency telescope should initially comprise 512 stations arranged in a large core with three spiral arms, spread over a distance of 65km. Each station will contain 256 individual antennas, representing more than 130,000 antennas in total.
In South Africa, 133 dish antennas shall be added to the existing 64-dish MeerKAT precursor telescope, totalling nearly 200 dishes to form the SKA’s mid-frequency telescope array. Most dishes will be concentrated in a core, with three spiral arms extending over 150km.
This forms part of the “design baseline”, an agreed description of the attributes of the telescope.
However, unlike single dish telescopes, the scalable nature of interferometers like the SKA means that more antennas can be added over time to increase its capability. The ultimate vision of the scientific community is to expand the SKA further across both sites and into other African countries. Such vision is commonly known as full SKA.
The cost of the SKA
As with other major infrastructure projects, the SKA’s projected cost has evolved over the years, as its science and engineering requirements have been refined and as currencies and inflation fluctuate. In 2020, The cost of the SKA including construction and the first 10 years of operations (2021-2030) is estimated to be around 1.9 billion euros in 2020 euros.
In early 2020, the SKA’s Board of Directors, backed by strong signals from governments, confirmed that a previous cost-cap for construction set in 2013, which had called for a reduction in the number of antennas initially constructed to fit within a tight budgetary envelope, would no longer apply. As a result, all efforts can focus on delivering the full design baseline described above.
Precursors and pathfinders
Even before the SKA comes online, a series of demonstrator telescopes and systems known as pathfinders and precursors, are already operational or under development across the world, paving the way for the kinds of technology which the SKA will need to pioneer to make the huge data available to scientists.
The key science goals
The SKA will be able to conduct transformational science, breaking new ground in astronomical observations. SKA scientists have focussed on various key science goals for the telescope, each of which will re-define our understanding of space as we know it.
From challenging Einstein’s seminal theory of relativity to the limits, looking at how the very first stars and galaxies formed just after the big bang, in a way never before observed in any detail, helping scientists understand the nature of a mysterious force known as dark energy, the discovery of which gained the Nobel Prize for physics, through to understanding the vast magnetic fields which permeate the cosmos, and, one of the greatest mysteries known to humankind…are we alone in the Universe, the SKA will truly be at the forefront of scientific research.
Early science observations are expected to start in the mid-2020s with a partial array.
Organisations from 14 countries are members of the SKA Organisation – Australia, Canada, China, France, Germany, India, Italy, New Zealand, Spain, South Africa, Sweden, Switzerland, The Netherlands and the United Kingdom. This global organisation is managed by the not-for-profit SKA Organisation, who have their headquarters at the Jodrell Bank Observatory, near Manchester in the United Kingdom. The participating countries page details more on the countries involved in the SKA.