The Location of the SKA
In 2012 the members of the SKA Organisation agreed on a dual site location for the Square Kilometre Array telescope as well as a third site for the SKA HQ.
This decision (Link to PDF) to co-locate the telescopes in two sites came after careful consideration of all of the science goals, industry goals and suitability in terms of location, sustainability, local considerations and factors relating to economics and the site infrastructure.
Why were two sites chosen to host the SKA Telescope?
In fact, whilst there are two primary sites hosting the majority of the SKA’s radio telescopes, in the case of the Africa site, countries all over the continent will also form part of the vast global array of radio telescopes which make up the SKA.
The eventual choice of two primary locations to host the telescopes was taken largely for scientific and strategic reasons and a perfect way to build up on the already existing infrastructures.
Site selection criteria
The following are some of the criteria that were taken into account:
- Radio frequency interference from mobile phones, TVs, radios and other electrical devices.
- The characteristics of the ionosphere (the upper part of the Earth’s atmosphere) and the troposphere (the lower part of the Earth’s atmosphere).
- Physical characteristics of the site including climate and subsurface temperatures.
- Connectivity across the vast extent of the telescope itself as well as to communications networks for worldwide distribution of data produced by the SKA.
- Infrastructure costs, including power supply and distribution.
- Operations and maintenance costs.
- The long term sustainability of the site as a radio quiet zone.
History of the site selection process
Following a request by the International SKA Steering Committee (ISSC) to the global radio astronomy community for initial site analyses of potential locations for the SKA, six responses were received over the course of 2003 and 2004. After careful evaluation of these responses by the Site Evaluation Working Group (SEWG), the ISSC accepted five countries as candidate locations for the SKA: Argentina, Australia, China, South Africa, and the USA. Subsequently, the USA withdrew its bid for the SKA site leaving the other four countries as contenders.
The Netherlands Institute for Radio Astronomy (ASTRON) was contracted by the International SKA Project Office (ISPO) to carry out Radio Frequency Interference (RFI) calibration measurements for a month at each of the candidates sites from March 2005 to late 2005. The candidates sites themselves also performed RFI measurements over a period of 1 year.
Proposals for the location of the SKA were received from the four candidates sites on 31 December 2005. Following a period of evaluation of the proposals and having taken account of the advice of an independent panel called the International SKA Site Advisory Committee, the ISSC decided that the short-list of acceptable sites for the SKA will comprise Australia and Southern Africa.
It was eventually concluded that both of these sites had equal merit in their location, and as such a dual site decision was made in 2012.
Modern super scale science projects require international collaboration,not only from a financial standpoint, as well as the scientific and engineering expertise. By combining the effort and focus provided by the global science community, ventures on the scale of the SKA are made possible.
The SKA Organisation, with its headquarters at Jodrell Bank near Manchester in the UK, has the huge but formidable role of coordinating relationships between the international partners and centralize the leadership of the project
As part of the advanced science operations and testing ahead of the full operations of the SKA commencing in the mid 2020’s two key precursor facilities are now being used and developed to test and also in some cases form part of the SKA itself. The SKA will be developed in a phased approach, more details of which can be found here
The MeerKAT precursor telescope located in South Africa will be incorporated into Phase one of the SKA, while the ASKAP telescope in Australia is being used as a testbed for promising new technologies. These two facilities are providing SKA scientists with invaluable data on the locations over the next decade which will help refine the research, development and construction of the SKA in these locations.
The following table shows the construction phases for the SKA, outlining the number of telescopes, and which site they will be located at.
|Type||Phase 1||Phase 2|
|Number of Antenna||Site||Number of Antenna||Site|
|Dishes||~200 (including 64 Meerkat Dishes)||Africa||~2000||Africa|
|36 ASKAP dishes||Australia|
|Low Frequency Aperture Array antennas||~130,000||Australia||up to 1,000,000||Australia|
|Mid Frequency Aperture Array Stations||250||Africa|
Note: Implementation of all aspects of SKA Phase 2 is subject to satisfactory technical performance of SKA Phase 1 components at both sites.
Our documentation section features many of the scientific papers produced during the study which led to the decision on the dual site location for the SKA Telescope.