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 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 in to 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 desert sites, through to the radio quietness, which comes from being some of the most remote locations on Earth.
South Africa’s Karoo desert 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 11 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 designing and developing a system which will require supercomputers faster than any in existence in 2015, and network technology that will generate more data traffic than the entire Internet.
The SKA will be developed over a phased timeline. Pre-construction development started in 2012 and will last until the latter half of this decade, involving the detailed design, implementation, R&D work, and contract preparation needed to bring the SKA’s first phase to construction readiness.
The main bulk of the SKA will be built in two main phases, between 2018 and the late 2020s, the first phase will involve testing the full system in a “proof of concept” manner.
For SKA Phase 1, Australia will host the low-frequency instrument with more than 500 stations, each containing around 250 individual antennas, whilst South Africa will host an array of some 200 dishes, incorporating the 64-dish MeerKAT precursor telescope.
Phase 2 will complete the telescope arrays at both sites, and become fully operational in the late 2020s, by which time the SKA will count with some 2000 high and mid frequency dishes and aperture arrays and a million low frequency antennas.
The SKA will already start conducting science observations in 2020 with a partial array.
The telescopes and arrays
Moving now from the drawing board to reality over the coming years, the SKA’s main instruments will include dishes and low frequency antennas, and potentially mid frequency aperture arrays in Phase 2.
The Cost of the SKA
In July 2013, the SKA Board passed the following resolution:
‘Following the recommendation of the Director-General of the SKA Organisation, the SKA Board has instructed the SKA Office to proceed with the design phase for SKA Phase 1 assuming a capital expenditure cost ceiling for construction of €650M. The evolution of the SKA Phase 1 project to fit within this cost ceiling will be guided both during the design phase and construction by scientific and engineering assessments of the baseline design undertaken by the SKA Office in collaboration with the community and SKA’s advisory bodies including the Science and Engineering Advisory Committee (SEAC). This decision is consistent with the primary objective of building an exciting, next-generation telescope capable of transformational science.’
Following a successful rebaselining process, the design of SKA1 is now broadly established and is within the cost-cap that was set. Teams can now work on refining the design towards construction.
The cost of constructing and operating the full SKA (Phases 1 and 2) is, as yet, not established. Any estimate must be based on costs supported by engineering.
The cost of SKA elements will be refined during 2015 now that each element has undergone its Preliminary Design Review. Some planned components of SKA Phase 2 are still in the early stages of a multi-year design process and the final costs of manufacture, installation and operation are unknown at this time. The construction costs of the full SKA will therefore be presented to the Board once credible estimates have been developed based on detailed engineering and design work. These may require refinement as the SKA Phase 2 science drivers are further developed.
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 start in 2020 with a partial array.
Organisations from eleven countries are members of the SKA Organisation – Australia, Canada, China, Germany, India, Italy, New Zealand, South Africa, Sweden, 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