The world's largest telescope - the Square Kilometre Array (SKA) - is set to kick off soon, with aspects such as functional and performance requirements and elaboration of preliminary designs set to be wrapped up by the middle of next year.
The SKA will include 500 000 antennas scattered across 3 000km in both Southern Africa and Australia. Construction of the first two phases is expected to begin in 2017 and conclude in 2024, at an estimated cost to member countries of EUR1.5 billion.
Once completed, the SKA will collect data from deep space, which is expected to date back to the "Big Bang". The aperture arrays and dishes of the SKA are expected to produce 10 times the volume of current global Internet traffic.
Proposals for the preconstruction design phase, worth around $114 million, are open until 10 June and the request for proposals splits the preconstruction phase into two. The first stage derives the functional and performance requirements, as well as elaborating on preliminary designs and is set to be wrapped up by mid-2014.
The second stage of the project involves detailed designs and procurement specifications necessary for construction of the first phase of the SKA, which is scheduled to wrap up in mid-2016.
According to the documentation released with the call for proposals, the SKA "will be one of a suite of new, large telescopes for the 21st century probing fundamental physics, the origin and evolution of the universe, the structure of the Milky Way Galaxy, the formation and distribution of planets, and astrobiology".
Probing life
Phase one of the telescope, which is to be built between 2016 and 2020, "will be in its own right a powerful scientific instrument", and will be followed by the second phase, which will be constructed between 2020 and 2024.
The first phase will see the addition of 190 dish antennas to expand the 64-dish MeerKAT precursor array, as well as projects in Australia gaining traction. SA and eight African partner countries will host the dish array in phase two of the SKA and will also host the phase two mid-frequency aperture array antennas.
At the end of the first phase, the SKA will have reached around 10% of its full capability, as the full scientific capability will be achieved with phase three, although the current focus is on the first two stages, which will inform phase three.
The first phase's science case and goals include examining unanswered questions in fundamental physics, astrophysics, and astrobiology. Two key aspects have been included, such as understanding the history and role of neutral hydrogen in the universe from the dark ages to the present-day.
The first phase also aims to detect and time binary pulsars and spin-stable millisecond pulsars in order to test theories of gravity to discover gravitational waves from cosmological sources, and to determine the equation of state of nuclear matter.
Among unanswered questions science has yet to resolve are aspects such as when the first stars were formed, whether Albert Einstein's theory of relativity is wrong, and how galaxies get their gas and form stars. The project will also probe the fate of the universe and how cosmic magnets work.
"The existence of life elsewhere in the universe has been a topic of speculation for millennia. The SKA will image nearby stellar nurseries, searching for orbiting disks of material in which planets are forming, perhaps not unlike how the Earth formed around the sun nearly five billion years ago."
The design of the telescope is being developed to allow for "exploration of the unknown", allowing for evolution of its capabilities. "This philosophy is essential as many of the outstanding questions of the 2020 to 2050 era - when the SKA will be in its most productive years - are likely not even known today."
Massive data
The SKA project office has developed a baseline design for the telescope based on earlier work and inputs from the community. According to the preliminary baseline document, the major SKA Observatory entities will be the SKA1-low and SKA1-projects in Australia and SKA1-mid in SA.
In each host country, there will be a science data processing centre, which is expected to be a supercomputing facility. "Sufficient on-site processing will be done to reduce to a manageable rate the data sent to the off-site science computing facility," says the documentation.
Earlier this month, it was announced that scientists from SKA SA would join IBM and the Netherlands Institute for Radio Astronomy (ASTRON) in a four-year collaboration to research new computing systems to deal with the big data challenge posed by the SKA.
The collaboration, dubbed the DOME project, is a public-private partnership launched by IBM and ASTRON last year in order to investigate emerging technologies for large-scale and efficient exascale computing for the SKA.
The science data processor will calibrate data, form images of sky brightness and further analyse time-domain effects. The SKA is likely to require "significant new developments" to handle the amount of data and achieve dynamic range targets without continuous human input, states the documentation.
"The precise nature and volume of this data will not be defined until the telescopes are closer to operations, and even then may only be defined in a preliminary way."
Mega dishes
SKA1-low, in Australia, will comprise an array of about 250 000 log-periodic dual-polarised antenna elements, in a 45km configuration. The antenna array will operate from 50MHz to around 350MHz. The required processing of the science data will be varied, and probably elaborate, says the documentation.
SKA1-survey, also in Australia, will primarily conduct surveys of large fractions of the sky, as well as mapping the sky both for spectral lines and continuum.
The telescope receptors will consist of array reflector antennas or dishes that will be a mixed array of about 96 dishes in total. SKA1-survey will cover the continuous frequency range from 650MHz to 1 670MHz.
SKA1-mid, to be located in SA, will primarily address observations of radio pulsars and observations of the 21cm hyperfine line of neutral hydrogen from the local universe, to moderate redshifts, as well as high sensitivity observations of continuum emitting objects.
The array will be a mixed array of 64, 13.5m diameter dishes from the MeerKAT array, and 190, 15m SKA1 dishes. They will be spread out over a radius of about 100km from the centre and will cover the continuous frequency range from 350MHz to at least 3 050MHz in three receiver bands.
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