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The SKA unpacked

How SA is benefiting from the project.

Nicola Mawson
By Nicola Mawson, Contributor.
Johannesburg, 09 May 2013

Construction of the mega telescope project - the Square Kilometre Array (SKA) - has started in earnest with the first MeerKAT antenna set to be installed by the end of the year, and all 64 dishes by the end of 2016.

MeerKAT, SA's prototype project, will be incorporated into the SKA. Construction will start in 2016/17, with some elements operational by 2020, and full operation under way in 2025.

The project is expected to see several spin-offs for SA, including skills development and advances in science. There are also potential ICT projects on the back of the mega telescope.

SA's site in the remote Karoo is currently a hub of construction activity with plans on track to build all 64 MeerKAT antennas by the end of 2016. Antenna one is set to be installed by the end of this year, says MeerKAT project manager Willem Esterhuyse in the SKA local office's latest newsletter.

The SKA will be a mega telescope, about 100 times more sensitive than the biggest existing radio telescope. The telescope array will comprise about 3 000 dish-shaped antennas and other hybrid receiving technologies, with a core of about 2 000 antennas and outlying stations of 30 to 40 antennas each, spiralling out of the core.

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".

Jasper Horrell, GM of science computing and innovation at SKA SA, says the benefits of the SKA in Africa are already being felt across a spectrum of society.

In the period leading up to the start of construction, SA will build the 64-dish antennas radio telescope, MeerKAT. Work on MeerKAT, the current phase of the SKA project, entails the design, testing and construction of 64 Gregorian offset dishes.

In the precursor phase, South African construction and engineering contracts have been awarded for the establishment of the Karoo site and the design and construction of the KAT-7 and MeerKAT arrays, says Horrell.

KAT-7, the MeerKAT's forerunner, is a seven-dish array that was completed a few years ago. The SKA project, which will construct the world's largest telescope, is expected to cost around EUR1.5 billion, which will be split between Africa and sites located in New Zealand and Australia. SA and eight partner countries in Africa will share about 70% of the project, with the rest being divided between Australia and New Zealand.

Horrell adds as phase one rolls out, there should be "significant opportunities for local business with their local knowledge and presence in the construction and ongoing operations of the enormous facility". The remote stations in African partner countries should also provide opportunities for local businesses with the appropriate skills to provide support and maintenance.

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.

Horrell says the more significant benefits are the longer-term and broader-reaching payoffs associated with the development of the skills and technologies needed for the SKA. "On the higher-tech side of the project, engineers from SKA SA and South African businesses are engaging in the design phase of the SKA, which is to be a worldwide effort organised through participation in work package consortia."

The SKA SA Human Capital Development programme is already playing a role in transforming the science and technology landscape in SA at universities and other tertiary institutions, says Horrell.

"South Africa is experiencing a reverse brain drain in the area of astronomy and associated technologies, and opportunities exist for young students to not only have access to world-leading supervisors locally, but also access to leading scientists and engineers globally."

SKA Timeline

1991 - Concept
2006 - Short listing of suitable sites
2008-12 - Telescope system design
2011 - Establish SKA Organisation as a legal entity
2012 - Site selection
2013-15 - Detailed design and pre-construction phase
2016-20 - Phase 1 construction
2020 - Full science operations with Phase 1
2020-24 - Phase 2 construction
2024 - Full science operations with Phase 2

In mid-2011, then minister of science and technology Naledi Pandor said "developing large-scale astronomy facilities, such as the MeerKAT and the SKA, can become a powerful driver of scientific, socio-economic and human capital development throughout the continent of Africa, for the benefit of the world".

The SKA is seen as an entry point and catalyst for involvement by companies that see the potential of Africa and African markets and are prepared to make investments in research and technology in SA and Africa in general, says Horrell.

Horrell adds there is significant interest from larger ICT players, for example, in establishing joint research projects in SA, linked to SKA technologies, but with aspirations of longer-term, broader application in areas outside of astronomy.

Scientists from SKA SA are also set to 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.

Horrell adds: "New technology and skills development projects are now possible with potential large spin-offs in the establishment of new local high tech business and with application to both government and business alike. The focus provided by the SKA is unlocking funding opportunities for such projects and generates the high level of interest and impetus required for successful execution."

Open for business

Last month, SKA SA said local industry and institutions, with appropriate existing expertise, could be eligible for financial assistance on a shared-cost, shared-risk basis to take part in the SKA design phase, extending to 2016.

"The SKA is an iconic and global science project and we are excited to be able to assist local industry and institutions with appropriate skills in participation in the initial design phase," said Horrell. "This involvement should serve to strengthen the global competitiveness of local organisations in high tech domains, focused on the SKA, but extending beyond radio astronomy."

Financial assistance for local organisations is being targeted in the areas of dishes, central signal processors (correlator/beamformer), science data processors, signal and data transport, and synchronisation and timing. Responses had to be in by 22 April.

South Africa is experiencing a reverse brain drain in the area of astronomy and associated technologies, Jasper Horrell, SKA.

The move follows the international organisation's request for proposals for the pre-construction design phase, worth around $114 million, which are open until 10 June. The request for proposals splits the pre-construction phase in two. The first stage derives the functional and performance requirements, as well as elaborates 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.

In February, Treasury announced that a total of R1.9 billion has been allocated over the next three years towards the SKA, which includes the demonstration telescope, MeerKAT. In 2012/13, R230.6 million was used for the SKA project. A total of EUR23.4 million in cash has already been committed for the pre-construction phase, while "in-kind" contributions are expected to exceed EUR90 million.

Powerful science

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 full scientific capability will be achieved with phase three. 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 answer 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."

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.

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."

Home grown

Fun SKA facts

* The data collected by the SKA in a single day would take nearly two million years to play back on an iPod.
* The SKA central computer will have the processing power of about 100 million PCs.
* The SKA will use enough optical fibre to wrap twice around the Earth.
* The dishes of the SKA will produce 10 times the global Internet traffic.
* The aperture arrays in the SKA could produce more than 100 times the global Internet traffic.
* The SKA will generate enough raw data to fill 15 million 64GB iPods every day.
* The SKA supercomputer will perform 1 018 operations per second - equivalent to the number of stars in three million Milky Way galaxies - in order to process all the data the SKA will produce.
* The SKA will be so sensitive it will be able to detect an airport radar on a planet 50 light-years away.
* The SKA will contain thousands of antennas with a combined collecting area of about one square kilometre.
* Analysts estimate the London Olympics was the most data-heavy yet - with some 60GB, the equivalent of 3 000 photographs, travelling across the network in the Olympic Park every second. This, however, is only equivalent to the data rate from about half a low frequency aperture array station in SKA phase one.

SKA1-mid, to be located in SA, will mostly 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.

MeerKAT, SA's prototype project, is being built in two phases, with the first - the seven-dish array prototype - being completed in 2010 and another 56 antennas on track to be built by 2016. "The project team is motivated to build the best telescope we can," Esterhuyse said. MeerKAT will account for 25% of the first phase of the SKA mid-frequency dish array.

"We are confident we will build it to budget, and on schedule, while exceeding the original specifications," said Esterhuyse. Discussions about integrating MeerKAT and the SKA are in progress between SKA SA and the International SKA project.

Various subsystems of MeerKAT are at the requirements review, or preliminary design review, stages. The full qualification, and critical design review, is expected to be completed early in 2014.

"Until the SKA is completed, MeerKAT will be the most sensitive radio interferometer in the world in the L-Band," Esterhuyse explains. His team has improved the sensitivity of the offset Gregorian dish design, leading to a 36% improvement in sensitivity, and an 86% improvement in survey speed, compared to the initial specifications.

By mid-April 2013, roads and civil works, as well as the electrical and fibre ducting reticulation for MeerKAT, should have been wrapped up.

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.

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