The Square Kilometre Array is a global science and engineering project to build the world’s largest radio telescope.
The Square Kilometre Array (SKA) project is an international effort to build the world’s largest radio telescope, with 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 use hundreds of thousands of radio telescopes, in three unique configurations, which will enable astronomers to monitor the sky in unprecedented detail and survey the entire sky thousands of times faster than any system currently in existence. The SKA telescopes will be co-located in Africa and in Australia. South Africa’s Karoo desert will cover the core of the high and mid frequencies of the radio spectrum which will have telescopes spread all over the continent, with Australia’s Murchison region covering the low frequency range and hosting the survey instrument.
Its three unique configurations will give the SKA unrivalled scope in observations, exceeding the image resolution quality of the Hubble Space Telescope by a factor of 50 times, and in the radio end of the spectrum!
Whilst also having 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, compliment and lead the way in scientific discovery.
Both South Africa’s Karoo region (as a core site) and Western Australia’s Murchison region 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.
A Global Effort
Whilst 11 member countries (including India, which is an associate member) are the cornerstone of the SKA, around 100 organisations across about 20 countries have participated 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 2013, and network technology that will generate more data traffic than the entire Internet.
The SKA will be developed over a phase timeline. With pre construction development commencing in 2012 going through to the latter half of this decade, and involve 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 mid 2020s, with 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 telescopes with more than 900 stations, each containing a bit less than 300 individual dipole antennas, as well as a 96-dish ‘SKA1-Survey’ telescope, incorporating the existing 36-dish ASKAP, whilst South Africa will host an array of 254 dishes, incorporating the 64-dish MeerKAT precursor telescope.
Phase 2 will complete the telescope arrays at both sites, and become fully operational in the mid 2020s, by which time, several thousand high frequency and mid frequency telescopes and aperture arrays will augment the millions of low frequency antenna.
The telescopes and arrays
Moving now from the drawing board to reality over the coming years, the SKA’s three main telescope types will include
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.’
The cost of operating SKA Phase 1 is under active investigation. Towards the end of 2014, the design consortia will provide information on operational costs, including power requirements, for all system elements of the SKA. This, together with the development of a detailed, overall operational plan, will enable the estimation of the operating costs of the Observatory.
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. There have been several, uninformed estimates of the cost of the full SKA, none of which have been based upon credible information.
We will have information on the cost of SKA elements late in 2014; these will be refined during 2015 after each element has undergone its Preliminary Design Review. Even then, some planned components of SKA Phase 2 are still in the early stages of a multi-year design process (e.g. dense aperture arrays) 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 5 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.
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