Square Kilometre Array

Short description: Radio telescope planned in Australia and South Africa

Square Kilometre ArrayFirst light| 2027 (projected)

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The Square Kilometre Array (SKA) is an intergovernmental radio telescope project being planned to be built in Australia and South Africa . Conceived in the 1990s, and further developed and designed by the late-2010s, when completed sometime in the 2020s it will have a total collecting area of approximately one square kilometre.[1][2] It will operate over a wide range of frequencies and its size will make it 50 times more sensitive than any other radio instrument. It will require very high performance central computing engines and long-haul links with a capacity greater than the global Internet traffic as of 2013.[3] If built as planned, it should be able to survey the sky more than ten thousand times faster than before.

With receiving stations extending out to a distance of at least 3,000 kilometres (1,900 mi) from a concentrated central core, it will exploit radio astronomy's ability to provide the highest resolution images in all astronomy. The SKA will be built in the southern hemisphere, with cores in South Africa and Australia, where the view of the Milky Way Galaxy is the best and radio interference at its least.[4] Four precursor facilities are already operating: MeerKAT and the Hydrogen Epoch of Reionization Array (HERA) in South Africa, and the Australian SKA Pathfinder (ASKAP) and Murchison Widefield Array (MWA) in Western Australia.[5]

The headquarters of the project are located at the Jodrell Bank Observatory in the UK.[6]

The SKA was estimated to cost €1.8 billion in 2014, including €650 million for Phase 1, which represented about 10% of the planned capability of the entire telescope array.[7][8] There have been numerous delays and rising costs over the nearly 30-year history of the intergovernmental project.[9]

Initial construction contracts began in 2018. Scientific observations with the fully completed array are not expected any earlier than 2027.[9][10]

On 12 March 2019, the Square Kilometre Array Observatory (SKAO) consortium was founded in Rome by seven initial member countries, with several others expected to join in the future. This international organisation is tasked with building and operating the facility. Construction is scheduled to begin July 2021.[11][12]

## Contents

* 1 History
* 2 Description
* 3 Key projects
* 3.1 Extreme tests of general relativity
* 3.2 Galaxies, cosmology, dark matter and dark energy
* 3.3 Epoch of re-ionization
* 3.4 Cosmic magnetism
* 3.5 Search for extraterrestrial life
* 4 Locations
* 5 Precursors, pathfinders and design studies
* 5.1 Precursor facilities
* 5.1.1 Australian SKA Pathfinder (ASKAP)
* 5.1.2 MeerKAT
* 5.1.3 Murchison Widefield Array (MWA)
* 5.1.4 Hydrogen Epoch of Reionization Array (HERA)
* 5.2 Pathfinders
* 5.2.1 Allen Telescope Array
* 5.2.2 LOFAR
* 5.3 Design studies
* 5.3.1 Data challenges
* 5.3.2 Technology Development Project (TDP)
* 6 Project risks
* 7 Opposition to the SKA project
* 8 See also
* 9 References
* 10 External links

## History

The Square Kilometre Array (SKA) was originally conceived in 1991 with an international working group set up in 1993. This led to the signing of the first Memorandum of Agreement in 2000.[13] Considerable early development work then followed. This culminated in the commencement of PrepSKA in 2008 leading to a full SKA design in 2012. Construction of Phase 1 will take place from 2018 to 2020 providing an operational array capable of carrying out the first science. Phase 2 will then follow for completion in 2025 providing full sensitivity for frequencies up to at least 14 GHz.

Australia's first radio quiet zone was established by the Australian Communications and Media Authority (ACMA) on 11 April 2005 specifically to protect and maintain the current "radio-quietness" of the main Australian SKA site at the Murchison Radio-astronomy Observatory.[14]

The SKA headquarters at Jodrell Bank, with the Lovell Telescope in the background

(As of 2018), the SKA was a global project with eleven[15] member countries that had the objective to answer fundamental questions about the origin and evolution of the Universe.[16] In the early days of planning, China vied to host the SKA, proposing to build several large dishes in the natural limestone depressions (karst) that dimple its southwestern provinces; China called their proposal Kilometer-square Area Radio Synthesis Telescope (KARST).[17][18] In April 2011, Jodrell Bank Observatory of the University of Manchester, in Cheshire, England was announced as the location for the project headquarters.[19]

In November 2011, the SKA Organisation was formed as an intergovernmental organization[20] and the project moved from a collaboration to an independent, not for profit, company.[21]

On 10 March 2012 it was reported that the SKA Site Advisory Committee had made a confidential report in February that the South African bid was stronger.[22] The final decision on the site by the project's board of directors was expected on 4 April 2012.[22] However a scientific working group was set up to explore possible implementation options of the two candidate host regions, and its report was expected in mid May 2012.[23]

In February 2012, a former Australian SKA Committee[clarification needed] chairman raised concerns with South African media about risks at the Australian candidate site, particularly in terms of cost, mining interference and land agreements. SKA Australia stated that all points had been addressed in the site bid.[24]

On 25 May 2012 it was announced that it had been determined that the SKA will be split over the South African and African sites and the Australia and New Zealand sites.[4] While New Zealand remained a member of the SKA Organisation in 2014, it appeared that no SKA infrastructure was likely to be located in New Zealand.[25]

In April 2015, the headquarters of the SKA project were chosen to be located at the Jodrell Bank Observatory, in the UK,[26][6] and officially opened in July 2019.

By February 2021, the members of the SKA Organisation were:[21][27]

* Australia: Department of Industry and Science
* Canada: National Research Council
* China: National Astronomical Observatories of the Chinese Academy of Sciences
* France: French National Centre for Scientific Research
* Germany: Max-Planck-Gesellschaft
* India: National Centre for Radio Astrophysics[28]
* Italy: National Institute for Astrophysics
* Portugal: Portuguese Space Agency, Portugal Space.
* South Africa: National Research Foundation
* Spain: Institute of Astrophysics of Andalusia[29]
* Sweden: Onsala Space Observatory
* Switzerland: École Polytechnique Fédérale de Lausanne
* The Netherlands: Netherlands Organisation for Scientific Research
* United Kingdom: Science and Technology Facilities Council

On 12 March 2019, the Square Kilometre Array Observatory (SKAO) was founded in Rome by seven initial member countries: Australia, China, Italy, the Netherlands, Portugal, South Africa and the United Kingdom. India and Sweden are expected to follow shortly, and eight other countries have expressed interest to join in the future. This international organisation is tasked with building and operating the facility, with the first construction contracts expected to be awarded in late 2020.[11] By mid-2019, the start of scientific observations are expected to start no earlier than 2027, with the date having "been pushed back repeatedly from an initial date of 2017."[9]

In July 2019, New Zealand withdrew from the project.[9]

## Description

Countries that participated in the preparatory phase of SKA[30]

The SKA will combine the signals received from thousands of small antennas spread over a distance of several thousand kilometres to simulate a single giant radio telescope capable of extremely high sensitivity and angular resolution, using a technique called aperture synthesis.[31] Some of the sub-arrays of the SKA will also have a very large field-of-view (FOV), making it possible to survey very large areas of sky at once.[32] One innovative development is the use of focal-plane arrays using phased-array technology to provide multiple FOVs.[33] This will greatly increase the survey speed of the SKA and enable several users to observe different pieces of the sky simultaneously, which is useful for (e.g.) monitoring multiple pulsars. The combination of a very large FOV with high sensitivity means that the SKA will be able to compile extremely large surveys of the sky considerably faster than any other telescope.[34]

The SKA will provide continuous frequency coverage from 50 MHz to 14 GHz in the first two phases of its construction. A third phase will then extend the frequency range up to 30 GHz.

* Phase 1: Providing ~10% of the total collecting area at low and mid frequencies by 2023 (SKA1).[35]
* Phase 2: Completion of the full array (SKA2) at low and mid frequencies by 2030.[36]

The frequency range from 50 MHz to 14 GHz, spanning more than two decades, cannot be realised using one design of antenna and so the SKA will comprise separate sub-arrays of different types of antenna elements that will make up the SKA-low, SKA-mid and survey arrays:

Artist's impression of a Low-Band SKA Sparse Aperture Array Station

Artist's impression of a SKA Dense Aperture Array Station

1. SKA-low array: a phased array of simple dipole antennas to cover the frequency range from 50 to 350 MHz. These will be grouped in 100 m diameter stations each containing about 90 elements.
2. SKA-mid array: an array of several thousand dish antennas (around 200 to be built in Phase 1) to cover the frequency range 350 MHz to 14 GHz. It is expected that the antenna design will follow that of the Allen Telescope Array using an offset Gregorian design having a height of 15 metres and a width of 12 metres.[35]
3. SKA-survey array: a compact array of parabolic dishes of 12–15 meters diameter each for the medium-frequency range, each equipped with a multi-beam, phased array feed with a large field of view and several receiving systems covering about 350 MHz – 4 GHz. The survey sub-array was removed from the SKA1 specification following a "rebaselining" exercise in 2015.[37]

The area covered by the SKA – extending out to ~3000 km – will comprise three regions:[31][38]

1. A central region containing about 5 km diameter cores of SKA-mid antennas (South Africa) and SKA-low dipoles (Western Australia). These central regions will contain approximately half of the total collecting area of the SKA arrays.
2. A mid region extending out to 180 km. This will contain dishes and pairs of SKA-mid and SKA-low stations. In each case they will be randomly placed within the area with the density of dishes and stations falling off towards the outer part of the region.
3. An outer region from 180 km to 3000 km. This will comprise five spiral arms, along which dishes of SKA-mid, grouped into stations of 20 dishes, will be located. The separation of the stations increases towards the outer ends of the spiral arms.

## Key projects

Artist's impression of the Offset Gregorian Antennas

Schematic of the SKA Central Region

The capabilities of the SKA will be designed to address a wide range of questions in astrophysics, fundamental physics, cosmology and particle astrophysics as well as extending the range of the observable universe. A number of key science projects that have been selected for implementation via the SKA are listed below.

### Extreme tests of general relativity

Main page: Astronomy:Tests of general relativity

For almost one hundred years, Albert Einstein's general theory of relativity has precisely predicted the outcome of every experiment made to test it. Most of these tests, including the most stringent ones, have been carried out using radio astronomical measurements. By using pulsars as cosmic gravitational wave detectors, or timing pulsars found orbiting black holes, astronomers will be able to examine the limits of general relativity such as the behaviour of spacetime in regions of extremely curved space. The goal is to reveal whether Einstein was correct in his description of space, time and gravity, or whether alternatives to general relativity are needed to account for these phenomena.

### Galaxies, cosmology, dark matter and dark energy

Main pages: Astronomy:Galaxy formation and evolution and Astronomy:Dark matter

The sensitivity of the SKA in the 21 cm hydrogen line will map a billion galaxies out to the edge of the observable Universe. The large-scale structure of the cosmos thus revealed will give constraints to determine the processes resulting in galaxy formation and evolution. Imaging hydrogen throughout the Universe will provide a three-dimensional picture of the first ripples of structure that formed individual galaxies and clusters. This may also allow the measurement of effects hypothetically caused by dark energy and causing the increasing rate of expansion of the universe.[39]

The cosmological measurements enabled by SKA galaxy surveys include testing models of dark energy,[40] gravity,[41] the primordial universe,[42] and fundamental cosmology,[43] and they are summarized in a series of papers available online.[44][45][46][47]

### Epoch of re-ionization

The SKA is intended to provide observational data from the so-called Dark Ages (between 300,000 years after the Big Bang when the universe became cool enough for hydrogen to become neutral and decouple from radiation) and the time of First Light (a billion years later when young galaxies are seen to form for the first time and hydrogen becomes ionized again). By observing the primordial distribution of gas, the SKA should be able to see how the Universe gradually lit up as its stars and galaxies formed and then evolved. This period of the Dark Ages, culminating in First Light, is considered the first chapter in the cosmic story of creation, and the resolving power required to see this event is the reason for the Square Kilometre Array's design. To see back to First Light requires a telescope 100 times more powerful than the biggest radio telescopes currently in the world, taking up 1 million square metres of collecting area, or one square kilometre.[48]

### Cosmic magnetism

It is still not possible to answer basic questions about the origin and evolution of cosmic magnetic fields, but it is clear that they are an important component of interstellar and intergalactic space. By mapping the effects of magnetism on the radiation from very distant galaxies, the SKA will investigate the form of cosmic magnetism and the role it has played in the evolving Universe.

### Search for extraterrestrial life

This key science program, called "Cradle of Life", will focus on three objectives: observing protoplanetary discs in habitable zones, searching for prebiotic chemistry, and contributing to the search for extraterrestrial intelligence (SETI).[49]

* The SKA will be able to probe the habitable zone of Sun-like protostars, where Earth-like planets or moons are most likely to have environments favourable for the development of life.[50] The signatures of forming Earth-like planets imprinted on circumstellar dust may be the most conspicuous evidence of their presence and evolution,[50] and may even detect planets capable of supporting life.[50][51]
* Astrobiologists will also use the SKA to search for complex organic compounds (carbon-containing chemicals) in outer space, including amino acids, by identifying spectral lines at specific frequencies.[50]
* The SKA will be capable of detecting extremely weak radio emission "leakage" from nearby extraterrestrial civilizations, if they exist.[50]

## Locations

The headquarters of the SKA are located at the University of Manchester's Jodrell Bank Observatory in Cheshire, England,[52] while the telescopes will be installed in Australia and South Africa.[53]

An automatic wideband radio scanner system was used to survey the radio frequency noise levels at the various candidate sites in South Africa.

Suitable sites for the SKA telescope must be in unpopulated areas with guaranteed very low levels of man-made radio interference. Four sites were initially proposed in South Africa, Australia, Argentina and China.[54] After considerable site evaluation surveys, Argentina and China were dropped and the other two sites were shortlisted (with New Zealand joining the Australian bid, and 8 other African countries joining the South African bid):

Australia: The core site is located at the Murchison Radio-astronomy Observatory (MRO) at Mileura Station near Boolardy in Western Australia 315 km north-east of Geraldton[55][56] on a flat desert-like plain at an elevation of about 460 metres.

South Africa: The core site is located at the Meerkat National Park, at an elevation of about 1000 metres in the Karoo area of the arid Northern Cape Province, with distant stations in Botswana, Ghana, Kenya, Madagascar , Mauritius, Mozambique, Namibia and Zambia.

## Precursors, pathfinders and design studies

Many groups are working globally to develop the technology and techniques required for the SKA. Their contributions to the international SKA project are classified as either: Precursors, Pathfinders or Design Studies.

* Precursor facility: A telescope on one of the two SKA candidate sites, carrying out SKA-related activity.
* Pathfinder: A telescope or programme carrying out SKA-related technology, science and operations activity.
* Design Study: A study of one or more major sub-systems of the SKA design, including the construction of prototypes

### Precursor facilities

CSIRO's ASKAP antennas at the MRO in Western Australia

#### Australian SKA Pathfinder (ASKAP)

Main page: Astronomy:Australian Square Kilometre Array Pathfinder

The Australian SKA Pathfinder, or ASKAP, is an A$100 million project which built a telescope array of thirty-six twelve-metre dishes. It employs advanced, innovative technologies such as phased array feeds to give a wide field of view (30 square degrees). ASKAP was built by CSIRO at the Murchison Radio-astronomy Observatory site, located near Boolardy in the mid-west region of Western Australia. All 36 antennas and their technical systems were officially opened in October 2012.[57]

#### MeerKAT

Main page: Astronomy:MeerKAT

MeerKAT is a South African project consisting of an array of sixty-four 13.5-metre diameter dishes as a world class science instrument, and was also built to help develop technology for the SKA. KAT-7, a seven-dish engineering and science testbed instrument for MeerKAT, near Carnarvon in the Northern Cape Province of South Africa was commissioned in 2012 and was up and running by May 2018 when all sixty-four 13.5-metre diameter (44.3 feet) dish antennae were completed, with verification tests then underway to ensure the instruments are functioning correctly.[58][needs update] The dishes are equipped with a number of high performance single pixel feeds to cover frequencies from 580 MHz up to 14 GHz.[59]

#### Murchison Widefield Array (MWA)

Main page: Astronomy:Murchison Widefield Array

The Murchison Widefield Array[60] is a low-frequency radio array operating in the frequency range 80–300 MHz that began upgraded operation in 2018 at the Murchison Radio-astronomy Observatory site in Western Australia.

#### Hydrogen Epoch of Reionization Array (HERA)

Main page: Astronomy:Hydrogen Epoch of Reionization Array

The HERA array is located in the South African Karoo Radio Astronomy Reserve. It is designed to study highly redshifted atomic hydrogen emission emitted prior to, and during the epoch of reionization.

### Pathfinders

* APERture Tile in Focus (Apertif)[61]
* Very Long Baseline Interferometry[62]
* Electronic MultiBeam Radio Astronomy ConcEpt[63]
* e-MERLIN[64]
* Expanded Very Large Array[65]
* Long Wavelength Array[66]
* SKA Molonglo Prototype (SKAMP)[67]
* NenuFAR[68][69]
* Giant Metrewave Radio Telescope[70]

#### Allen Telescope Array

Main page: Astronomy:Allen Telescope Array

The Allen Telescope Array uses innovative 6.1m offset Gregorian dishes equipped with wide band single feeds covering frequencies from 500 MHz to 11 GHz. The 42-element array in operation by 2017 is to be extended to 350 elements. The dish design has explored methods of low-cost manufacture.[71]

#### LOFAR

Main page: Astronomy:Low-Frequency Array (LOFAR)

LOFAR —a €150 million Dutch-led project— a novel low-frequency phased aperture array spread over northern Europe. An all-electronic telescope covering low frequencies from 10 to 240 MHz, it came online from 2009 to 2011. LOFAR was in 2017 developing crucial processing techniques for the SKA.[72][needs update]

### Design studies

Data challenges of SKA pathfinders

Challenge | Specifications[73]
budgeted for ASKAP
Requirements for the SKA itself are about 100 times greater.
Large bandwidth from
telescope to processor  | ~10 Tbit/s from antennas to correlator (< 6 km)
40 Gbit/s from correlator to processor (~ 600 km)
Large processing power  | 750 Tflop/s expected/budgeted
1 Pflop desired
Power consumption
of processors  | 1 MW at site
10 MW for processor
Pipeline processing
essential  | including data validation, source extraction,
cross-identification, etc.
Storage and duration
of data  | 70 PB/yr if all products are kept
5 PB/yr with current funding
8 h to write 12 h of data to disk at 10GB/s
Retrieval of data
by users  | all data in public domain
accessed using VO tools & services
Data-intensive research  | data mining, stacking,
cross-correlation, etc.

* Aperture Array Verification Programme[74]
* Canadian SKA Program[75]
* Preparatory Study for the SKA[76]
* Square Kilometre Array Design Studies (SKADS)[77]
* Electronic MultiBeam Radio Astronomy ConcEpt (EMBRACE)[78]
* BEST

#### Data challenges

The amount of sensory data collected poses a huge storage problem, and will require real-time signal processing to reduce the raw data to relevant derived information. In mid 2011 it was estimated the array could generate an exabyte a day of raw data, which could be compressed to around 10 petabytes.[79] China, a founding member of the project, has designed and constructed the first prototype of the regional data processing centre. An Tao, head of the SKA group of the Shanghai Astronomical Observatory stated, "It will generate data streams far beyond the total Internet traffic worldwide." The Tianhe-2 supercomputer was used in 2016 to train the software. The processing of the project will be performed on Chinese designed and manufactured[80][81] Virtex-7 processors by Xilinx, integrated into platforms by the CSIRO.[82] China has pushed for a unified beam forming design that has led other major countries to drop out of the project.[83] Canada continues to use Altera(Intel) Stratix-10 processors[84] although it is illegal for any US company to export high end Intel FPGAs or any related CSP design details or firmware to China[85] amid the US-embargo[86][87][88][89] which will severely limit cooperation.

#### Technology Development Project (TDP)

The Technology Development Project, or TDP, is a US$12 million project to specifically develop dish and feed technology for the SKA. It is operated by a consortium of universities[clarification needed] led by Cornell University and was completed in 2012.[90]

## Project risks

Potential risks for priority astronomical sites in South Africa are protected by the Astronomy Geographic Advantage Act of 2007. Put in place to specifically support the South African SKA bid, it outlaws all activities that could endanger scientific operation of core astronomical instruments. In 2010, concerns were raised over the will to enforce this law when Royal Dutch Shell applied to explore the Karoo for shale gas using hydraulic fracturing, an activity that would have the potential to increase radio interference at the site.[91]

An identified remote station location for the southern African array in Mozambique was subject to flooding and excluded from the project,[92] despite the SKA Site Selection Committee technical analysis reporting that all African remote stations could implement flood mitigation solutions.[93]

During 2014, South Africa experienced a month-long strike action by the National Union of Metalworkers (NUMSA), which added to the delays of the installation of dishes. The plan was to have six dishes operational by November, but only one MeerKAT dish stands on the Karoo site in the Northern Cape.[94]

The largest risk to the overall project is probably its budget, which up until now has not been committed.[95]

## Opposition to the SKA project

There has been opposition to the project from farmers and businesses, as well as individuals, since the project's inception.[96] The advocacy group called Save the Karoo has stated that the radio quiet zone will create further unemployment in the South African region where unemployment is already above 32%.[97] Farmers had stated that the agriculture-based economy in the Karoo would collapse if they were forced to sell their land.[98][99]

## See also

* Five-hundred-meter Aperture Spherical Telescope
* KARST – a 1990s Chinese proposal to host the SKA
* List of radio telescopes
* LOFAR
* Mills Cross Telescope – related to the SKA development
* Simon Ratcliffe
* Project Cyclops

## References

1. ↑ "Facts and figures". SKA Organisation. http://www.skatelescope.org/about/facts-figures/.
2. ↑ Spie (2014). "Philip Diamond plenary: The Square Kilometre Array: A Physics Machine for the 21st Century". SPIE Newsroom. doi:10.1117/2.3201407.12.
3. ↑ http://www.dropbox.com/s/n7ghen7sb8h2tog/SKA_Prospectus.pdf , The Square Kilometre Array, p.19
4. ↑ 4.0 4.1 Amos, Jonathan (25 May 2012). "Africa and Australasia to share Square Kilometre Array". BBC. https://www.bbc.co.uk/news/science-environment-18194984.
5. ↑ "Precursors and Pathfinders". https://www.skatelescope.org/precursors-pathfinders-design-studies/.
6. ↑ 6.0 6.1 UK to be giant telescope's HQ . Jonathan Amos, BBC News. 29 April 2015.
7. ↑ "The project timeline". SKA Organisation. http://www.skatelescope.org/about/project/.
8. ↑ "SKA site bid outcome". SKA Africa. http://www.ska.ac.za/about/bid.php.
9. ↑ 9.0 9.1 9.2 9.3 "New Zealand pulls out of the Square Kilometre Array after benefits questioned". Physics World (IOP Publishing). 4 July 2019. https://physicsworld.com/a/new-zealand-pulls-out-of-the-square-kilometre-array-after-benefits-questioned.
10. ↑ https://www.skatelescope.org/wp-content/uploads/2018/08/16231-Factsheets-operational-model-v4.pdf Template:Bare URL PDF
11. ↑ 11.0 11.1 "Founding Members Sign SKA Observatory Treaty" (Press release). Square Kilometre Array Organisation. 12 March 2019. Archived from the original on 30 March 2019. Retrieved 14 March 2019.
12. ↑ World's largest radio telescope to be built after almost 30 years of planning space.com, 2021-07-01
13. ↑ "SKA Timeline - SKA UK". https://unitedkingdom.skatelescope.org/ska-project/ska-timeline/.
14. ↑ "Planning for the radio astronomy service". http://www.acma.gov.au/WEB/STANDARD/pc=PC_100628.
15. ↑ "SKA Participating Countries". https://www.skatelescope.org/participating-countries/.
16. ↑ Redfern, Martin (31 March 2011). "World's biggest radio telescope, Square Kilometre Array". BBC News. https://www.bbc.co.uk/news/science-environment-12891215.
17. ↑ Nan, R. (16 June 2002). "Kilometer-square Area Radio Synthesis Telescope—KARST". https://www.skatelescope.org/uploaded/8481_17_memo_Nan.pdf.
18. ↑ Su, Yan (Feb 2003). "An Optimal Design of Array Configuration of KARST for SKA". Acta Astronomica Sinica 44: 31. Bibcode: 2003AcASn..44S..31S. http://zmtt.bao.ac.cn/xian/proceedings/SuY/fin/SuY.pdf.
19. ↑ "Jodrell Bank chosen as base for largest radio telescope". BBC News. 2 April 2011. https://www.bbc.co.uk/news/science-environment-12947435.
20. ↑ "First country has approved participation in constructing the largest telescope the world has ever known". https://www.universal-sci.com/headlines/2019/8/20/first-country-has-approved-participation-in-constructing-the-largest-telescope-the-world-has-ever-known.
21. ↑ 21.0 21.1 "The organisation". SKA Organisation. http://www.skatelescope.org/the-organisation/.
22. ↑ 22.0 22.1 Flitton, Daniel (10 March 2012). "Australia on the outer for largest space telescope". The Age. http://www.theage.com.au/national/australia-on-the-outer-for-largest-space-telescope-20120309-1upwr.html.
23. ↑ "Further delays signalled in super-telescope plan". The Australian. AFP. 5 April 2012. http://www.theaustralian.com.au/australian-it/further-delays-signalled-in-super-telescope-plan/story-e6frgakx-1226319328674.
24. ↑ Carpenter, Avery (22 February 2012). "Oz telescope body under microscope after ex-chairman raises difficult questions". The Star. http://www.iol.co.za/the-star/oz-telescope-body-under-microscope-after-ex-chairman-raises-difficult-questions-1.1239657.
25. ↑ "Australia - SKA Telescope". SKA. 2014. https://www.skatelescope.org/location/australia/.
26. ↑ "The SKA Organisation". SKA Organisation. https://www.skatelescope.org/ska-organisation/.
27. ↑ "Germany joins the SKA Organisation". 20 December 2012. http://www.mpifr-bonn.mpg.de/99606/news_publication_6728490?c=2169.
28. ↑ "India's National Centre for Radio Astrophysics becomes the 11th full SKA Organisation member". SKA Organisation. 11 August 2014. https://www.skatelescope.org/news/indias-ncra-becomes-11th-full-skao-member/.
29. ↑ "Spain joins the SKA Organisation - SKA Telescope". 19 June 2018. https://www.skatelescope.org/news/spain-joins-skao/.
30. ↑ "Participating countries". SKA Organisation. http://www.skatelescope.org/the-organisation/history-of-the-organisation/participating-countries/.
31. ↑ 31.0 31.1 "The SKA Layout". https://www.skatelescope.org/layout/.
32. ↑ "The World's Largest Radio Telescope Takes A Major Step Towards Construction". 9 March 2015. https://www.skatelescope.org/news/worlds-largest-radio-telescope-near-construction/.
33. ↑ "SKA Aperture Arrays". https://www.skatelescope.org/aperture-arrays/.
34. ↑ "How will SKA1 be better than today's best radio telescopes? [image"]. https://www.skatelescope.org/wp-content/uploads/2015/03/SKA-3-aspects-Infographic_OP-rgb.jpg.
35. ↑ 35.0 35.1 "SKA1". http://astronomers.skatelescope.org/ska1/.
36. ↑ "SKA2". http://astronomers.skatelescope.org/ska2/.
37. ↑ McPherson, A.. "REPORT AND OPTIONS FOR RE-BASELINING OF SKA-1". SKAO. https://www.skatelescope.org/wp-content/uploads/2014/03/SKA-TEL-SKO-0000229_Report-and-Options-for-Re-Baselining-of-SKA-1-Word_Amm-signed.pdf.
38. ↑ Dewdney, P. E.. "SKA Baseline Design". https://www.skatelescope.org/wp-content/uploads/2012/07/SKA-TEL-SKO-DD-001-1_BaselineDesign1.pdf.
39. ↑ "Galaxy Evolution, Cosmology And Dark Energy – Further Information". Skatelescope.org. 25 May 2012. http://www.skatelescope.org/the-science/ska-key-science-projects/ska-key-science-projects/galaxy-evolution/.
40. ↑ Philip Bull; Stefano Camera; Alvise Raccanelli; Chris Blake; Pedro G. Ferreira; Mario G. Santos; Dominik J. Schwarz (2015). "Measuring baryon acoustic oscillations with future SKA surveys". PoS AASKA () 024 14 (2015): 24. Bibcode: 2015aska.confE..24B.
41. ↑ Alvise Raccanelli; Philip Bull; Stefano Camera; David Bacon; Chris Blake; Olivier Dore; Pedro Ferreira; Roy Maartens et al. (2015). "Measuring redshift-space distortions with future SKA surveys". Advancing Astrophysics with the Square Kilometre Array (Aaska14): 31. Bibcode: 2015aska.confE..31R. https://archive.org/details/arxiv-1501.03821.
42. ↑ S. Camera; A. Raccanelli; P. Bull; D. Bertacca; X. Chen; P.G. Ferreira; M. Kunz; R. Maartens et al. (2015). "Cosmology on the Largest Scales with the SKA". Proceedings of Advancing Astrophysics with the Square Kilometre Array — PoS(AASKA14). pp. 025. doi:10.22323/1.215.0025.
43. ↑ Dominik J. Schwarz; David Bacon; Song Chen; Chris Clarkson; Dragan Huterer; Martin Kunz; Roy Maartens; Alvise Raccanelli et al. (2015). "Testing foundations of modern cosmology with SKA all-sky surveys". Advancing Astrophysics with the Square Kilometre Array (Aaska14): 32. Bibcode: 2015aska.confE..32S. https://archive.org/details/arxiv-1501.03820.
44. ↑ Roy Maartens; Filipe B. Abdalla; Matt Jarvis; Mario G. Santos (2015). "Cosmology with the SKA -- overview". arXiv:1501.04076 [astro-ph.CO].
45. ↑ Mario G. Santos; Philip Bull; David Alonso; Stefano Camera; Pedro G. Ferreira; Gianni Bernardi; Roy Maartens; Matteo Viel et al. (2015). "Cosmology with a SKA HI intensity mapping survey". PoS AASKA () 019 14 (2015): 19. Bibcode: 2015aska.confE..19S.
46. ↑ Filipe B. Abdalla; Philip Bull; Stefano Camera; Aurélien Benoit-Lévy; Benjamin Joachimi; Donnacha Kirk; Hans-Rainer Klöckner; Roy Maartens et al. (2015). "Cosmology from HI galaxy surveys with the SKA". Advancing Astrophysics with the Square Kilometre Array (Aaska14): 17. Bibcode: 2015aska.confE..17A. https://archive.org/details/arxiv-1501.04035.
47. ↑ Matt J. Jarvis; David Bacon; Chris Blake; Michael L. Brown; Sam N. Lindsay; Alvise Raccanelli; Mario Santos; Dominik Schwarz (2015). "Cosmology with SKA Radio Continuum Surveys". Advancing Astrophysics with the Square Kilometre Array (Aaska14): 18. Bibcode: 2015aska.confE..18J. https://archive.org/details/arxiv-1501.03825.
48. ↑ RiAus 2011, Radio Astronomy: Something Kinda Awesome, (SKA), viewed 1st October 2014, http://vimeo.com/23460933/
49. ↑ The Square Kilometre Array Project Description for Astro 2010 -Response to Program Prioritization Panels. James Cordes. 1 April 2009.
50. ↑ 50.0 50.1 50.2 50.3 50.4 SKA - Cradle Of Life . T.J.W. Lazio, J.C. Tarter, D.J. Wilner. 2004.
51. ↑ Curtin Institute of Radio Astronomy \- Cradle of Life. April 2015.
52. ↑ "Construction starts on SKA Organisation headquarters". SKA Organisation. 18 April 2012. http://www.skatelescope.org/news/construction-starts-ska-organisation-headquarters/.
53. ↑ Co-hosting the SKA . SKA
54. ↑ Koenig, Robert (18 August 2006). "RADIO ASTRONOMY: Candidate Sites for World's Largest Telescope Face First Big Hurdle". Science (AAAS) 313 (5789): 910–912. doi:10.1126/science.313.5789.910. PMID 16917038.
55. ↑ Amos, J. Nations vie for giant telescope , BBC News, 28 September 2006.
56. ↑ Science Network WA, 16 February 2007
57. ↑ Osborne, Darren (5 October 2012). "Outback observatory open for business - ABC News (Australian Broadcasting Corporation)". ABC News (Abc.net.au). http://www.abc.net.au/news/2012-10-05/outback-observatory-open-for-business/4298094.
58. ↑ Tshangela, Lebo (16 May 2018). "MeerKAT telescope is complete". SABC News. http://www.sabcnews.com/sabcnews/meerkat-telescope-is-complete/.
59. ↑ "SKA SA – Square Kilometre Array radio telescope (SKA) South Africa". http://www.ska.ac.za.
60. ↑ "MWA - Home". http://www.mwatelescope.org/.
61. ↑ Tom Osterloo; Marc Verheijen; Wim van Cappellen (10–14 June 2010). "The latest on Apertif". ISKAF2010 Science Meeting. Bibcode: 2010iska.meetE..43O. http://pos.sissa.it/archive/conferences/112/043/ISKAF2010_043.pdf. Retrieved 15 April 2013.
62. ↑ Aerospace-Technology.com
63. ↑ "Electronic Multi Beam Radio Astronomy ConcEpt". http://www.skads-eu.org/p/embraceConcept.php.
64. ↑ Beswick, Rob. "e-MERLIN / VLBI National Radio Astronomy Facility - e-MERLIN". http://www.e-merlin.ac.uk/.
65. ↑ "Expanded VLA". http://www.aoc.nrao.edu/evla.
66. ↑ "Long Wavelength Array". http://lwa.phys.unm.edu/.
67. ↑ Gaensler, Bryan. "Sydney Institute for Astronomy - The University of Sydney". http://www.physics.usyd.edu.au/sifa/Main/SKAMP.
68. ↑ "NENUFAR website". http://nenufar.obs-nancay.fr.
69. ↑ "French NenuFAR telescope granted SKA Pathfinder status - SKA Telescope". 5 September 2014. https://www.skatelescope.org/news/french-nenufar-telescope-granted-ska-pathfinder-status/.
70. ↑ "India's GMRT telescope granted SKA pathfinder status" (in en). 6 February 2015. https://www.skatelescope.org/news/indias-gmrt-telescope-becomes-ska-pathfinder/.
71. ↑ "The Allen Telescope Array - SETI Institute". http://www.seti.org/ata.
72. ↑ "LOFAR - LOFAR". http://www.lofar.org/.
73. ↑ Ray P. Norris (7 January 2011). 2010 Sixth IEEE International Conference on e-Science Workshops: Data Challenges for Next-generation Radio Telescopes. pp. 21. doi:10.1109/eScienceW.2010.13. ISBN 978-1-4244-8988-6.
74. ↑ "The Square Kilometre Array - SKA-AAVP". http://www.ska-aavp.eu/.
75. ↑ "Home - SKA". http://www.skatelescope.ca/.
76. ↑ "PrepSKA". http://www.jb.man.ac.uk/prepska.
77. ↑ "SKADS Technology". SKADS. http://www.skads-eu.org/p/technology.php.
78. ↑ "EMBRACE". ASTRON. http://www.astron.nl/r-d-laboratory/ska/embrace/embrace.
79. ↑ "SKA telescope to generate more data than entire Internet in 2020". Computerworld. IDG Communications. 7 July 2011. http://www.computerworld.com.au/article/392735/ska_telescope_generate_more_data_than_entire_internet_2020/.
80. ↑ "Taiwan's TSMC says chip shipments to Huawei not affected by U.S. ban". Reuters. 23 May 2019. https://www.reuters.com/article/us-huawei-tech-usa-tsmc/taiwans-tsmc-says-chip-shipments-to-huawei-not-affected-by-u-s-ban-idUSKCN1ST08O. "China’s Huawei Technologies Co Ltd are not affected by U.S. action aimed at curbing the telecom equipment maker’s access to American technology."
81. ↑ "Xilinx Powers Huawei FPGA Accelerated Cloud Server". 6 September 2017. https://www.xilinx.com/news/press/2017/xilinx-powers-huawei-fpga-accelerated-cloud-server.html. "Huawei has chosen high performance Virtex® UltraScale+™ FPGAs to power their first FP1 instance as part of a new accelerated cloud service."
82. ↑ Kooistra, E.; Hampson, G. A.; Gunst, A. W.; Bunton, J. D.; Schoonderbeek, G. W.; Brown, A. (2017). "Gemini FPGA Hardware Platform for the SKA Low Correlator and Beamformer". 2017 XXXIInd General Assembly and Scientific Symposium of the International Union of Radio Science (URSI GASS). pp. 1–4. doi:10.23919/URSIGASS.2017.8104976. ISBN 978-90-825987-0-4. https://www.researchgate.net/publication/316324649.
83. ↑ John Bunton (10 February 2017). "The SKA LOW correlator design challenge". CSIRO. p. 30. https://irasr.aut.ac.nz/__data/assets/pdf_file/0009/68085/John-Bunton-C4SKA_LowAimsHighpptx.pdf.
84. ↑ McNamara, Dan (15 May 2018). "Intel FPGAs: Accelerating the Future". Intel. https://newsroom.intel.com/editorials/intel-fpgas-accelerating-future/#gs.yv2lyq. "Canada’s NRC is helping to build the next-generation Square Kilometre Array (SKA) radio telescope...NRC’s design embeds Intel® Stratix® 10 SX FPGAs"
85. ↑ "Electronic Code of Federal Regulations: PART 121—THE UNITED STATES MUNITIONS LIST". 22 August 2019. https://www.ecfr.gov/cgi-bin/text-idx?SID=86008bdffd1fb2e79cc5df41a180750a&node=22:1.0.1.13.58&rgn=div5. ""16) Hybrid (combined analogue/digital) computers specially designed for modeling, simulation, or design integration of systems enumerated in paragraphs (a)(1), (d)(1), (d)(2), (h)(1), (h)(2), (h)(4), (h)(8), and (h)(9) of USML Category IV or paragraphs (a)(5), (a)(6), or (a)(13) of USML Category VIII (MT if for rockets, SLVs, missiles, drones, or UAVs capable of delivering a payload of at least 500 kg to a range of at least 300 km or their subsystems. See note 2 to paragraph (a)(3)(xxix) of this category);""Analog-to-digital converters, usable in the system in Item 1, having either of the following characteristics: (1) Analog-to-digital converter "microcircuits", which are "radiation hardened" or have all of the following characteristics: (i) Having a resolution of 8 bits or more;" "Item 1—Category I Complete rocket systems (including ballistic missile systems, space launch vehicles, and sounding rockets (see §121.1, Cat. IV(a) and (b))) and unmanned air vehicle systems (including cruise missile systems, see §121.1, Cat. VIII (a), target drones and reconnaissance drones (see §121.1, Cat. VIII (a))) capable of delivering at least a 500 kg payload to a range of at least 300 km.""
86. ↑ "Overview of Cryptography and the Defence Trade Controls Act 2012". Department of Defense(Australia). http://www.defence.gov.au/ExportControls/Cryptography.asp.
87. ↑ "Australian Export Controls and ICT". Department of Defense(Australia). http://www.defence.gov.au/ExportControls/ICT.asp.
88. ↑ "Politics, not security, behind Huawei, ZTE allegations, say analysts". 8 October 2012. https://www.computerworld.com/article/2492071/politics--not-security--behind-huawei--zte-allegations--say-analysts.html.
89. ↑ Kan, Michael (9 April 2015). "U.S. stops Intel from selling Xeon chips to Chinese supercomputer projects". Computerworld. https://www.computerworld.com/article/2908371/us-stops-intel-from-selling-xeon-chips-to-chinese-supercomputer-projects.html.
90. ↑ Chatterjee, Shami. "Welcome to the SKA TDP Website". http://skatdp.astro.cornell.edu/.
91. ↑ Nordling, Linda (22 March 2011). "Mining plans pose threat to South African astronomy site". Nature. http://www.nature.com/news/2011/110322/full/news.2011.174.html?s=news_rss.
92. ↑ "Mozambique: Exact Location of SKA Telescope Sought". AllAfrica. 26 June 2012. http://allafrica.com/stories/201206270018.html.
93. ↑ "Report and Recommendation of the SKA Site Advisory Committee (SSAC)". http://www.skatelescope.org/uploaded/34228_120216_SSAC.Report_web.pdf.
94. ↑ Butoi, Mario (7 November 2014). "October 2014 - Strike delays SKA Dish Installations". Mail & Guardian. http://mg.co.za/article/2014-10-30-strike-delays-ska-dish-installations.
95. ↑ "SKA Project". SKA Organisation. https://www.skatelescope.org/project/.
96. ↑ "Astronomers and sheep farmers butt heads over the Square Kilometer Array". The Economist. 5 January 2017. https://www.economist.com/news/middle-east-and-africa/21713855-radio-telescope-project-encounters-nimbyism-remote-part-south.
97. ↑ "Save the Karoo". http://savethekaroo.com/.
98. ↑ Sarah, Wild (22 June 2016). "In South Africa, Opposition Flares against Giant SKA Radio Telescope". https://www.scientificamerican.com/article/in-south-africa-opposition-flares-against-giant-ska-radio-telescope/.
99. ↑ Wild, Sarah (23 June 2016). "Giant SKA telescope rattles South African community" (in en). Nature 534 (7608): 444–446. doi:10.1038/534444a. PMID 27337317. Bibcode: 2016Natur.534..444W.

## External links

International

* SKA website
* SKA on Scholarpedia

Australia/NZ

* SKA Australia web site
* "Inside the Square Kilometre Array", Cosmos magazine online, January 2012
* "The Square Kilometre Array Category", The Conversation, 2011/12
* "Australian SKA Planning Office Newsletter". CSIRO. 10 April 2007. http://www.atnf.csiro.au/news/aspo-newsletter/ASPO_newsletter_10.pdf.
* Boolardy Station and the Murchison Radio-Astronomy Observatory (MRO) – University of Western Australia
* Photographs from the Boolardy site, June 2010
* A Trojan Affair \- Novel about the SKA

Canada

* Canadian SKA Consortium web site

Europe

* SKA Design Studies web site

South Africa

* SKA South Africa web site

Other

* Merrifield, Michael; Crowther, Paul. "Where to Build The Square Kilometre Array?". Deep Space Videos. Brady Haran. http://www.deepskyvideos.com/videos/other/SKA_decision.html.

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(List)|

| Individual
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Interferometers|

* Allen Telescope Array (ATA, California, US)
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* One-Mile Telescope (UK)
* Primeval Structure Telescope (PaST, China)
* Square Kilometre Array (SKA, Australia, South Africa)
* Submillimeter Array (SMA, US)
* Very Large Array (VLA, New Mexico, US)
* Very Long Baseline Array (VLBA, US)
* Westerbork Synthesis Radio Telescope (WSRT, Netherlands)

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* HALCA (Japan)
* Spektr-R (Russia)

Observatories|

* Algonquin Radio Observatory (Canada)
* Haystack Observatory (US)
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* Onsala Space Observatory (Sweden)
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* DRAO (Canada)
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* John D. Kraus
* Bernard Lovell
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* Joseph Lade Pawsey
* Ruby Payne-Scott
* Arno Penzias
* Grote Reber
* Martin Ryle
* Govind Swarup
* Gart Westerhout
* Paul Wild
* Robert Wilson

Related articles|

* Radio propagation
* Interferometry
* Aperture synthesis
* SETI (Wow! signal, Radio signal from HD 164595)
* Pulsar timing array
* Cosmic microwave background radiation

* Submillimetre astronomy
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