Frequently Asked Questions

In Australia and South Africa, the two best locations that were identified as SKA telescope hosts after extensive site testing around the world.

In South Africa, the site is located in the Karoo near Carnarvon, in the Northern Cape province. In Australia, the SKA site is located in the Murchison shire, inland from Geraldton, Western Australia. The SKAO recognises and acknowledges the Indigenous peoples and cultures that have traditionally lived on the lands on which the SKAO facilities are located. In Australia, the Wajarri Yamaji people are the traditional owners of the land on which SKA-Low is being built.

The ultimate ambition is to expand the telescopes further both in Australia and in Africa, extending into African partner countries across the continent: Botswana, Ghana, Kenya, Madagascar, Mauritius, Mozambique, Namibia and Zambia.

Radio telescopes must be located as far away as possible from human-made electronics or machines that emit radio waves, which could interfere with the ability of the telescopes to detect faint radio signals from the rest of the Universe. This is called radio frequency interference (RFI) and is to radio astronomers what light pollution is to their optical counterparts. Both SKA telescopes are being built in nationally designated radio quiet zones, which help to protect the telescopes from this interference from the ground.

This protection does not apply to interference from space, however, so notably does not protect against the negative impact of so-called satellite mega-constellations. The SKAO is active on this topic, working with industry to identify mitigation measures, helping to bring the topic to the attention of international policy-makers via the United Nations Committee on the Peaceful Uses of Outer Space, and since 2022 co-hosting the International Astronomical Union's Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference alongside the US National Science Foundation's NOIRLab.

In short: a combination of smart design and cutting-edge technology, in addition to the sheer scale of the telescopes.

The popular perception of a radio telescope is a single large dish. However, there are structural and engineering limits on how big a single dish can be. To build bigger telescopes, astronomers use a technique called interferometry, using large numbers of smaller antennas connected together by optical fibre networks and working as a single virtual telescope, called an array - this is how both SKA telescopes have been designed.

The more antennas, the larger the effective collecting area and the greater the sensitivity (i.e. the ability to see fainter details) to detect the very weak cosmic radio signals. More antennas spread over longer distances also means that the images made are of finer resolution than is possible with a single antenna. The SKA telescopes will produce the sharpest pictures of the sky of any current radio telescopes. 

As the SKA telescopes will have so many antennas (more than 130,000 log-periodic antennas in the case of SKA-Low, and 197 dishes for SKA-Mid), significant effort has gone into developing software and hardware that will be able to handle the flood of data they will collect. As well as on-site processing, each telescope will have a dedicated supercomputer, each with a computing power that would put them in the top five fastest supercomputers in the world in 2022.

Designing and building the SKA telescopes has required the development of cutting-edge technologies. Such innovations will continue through the construction and operations phases, in order for the SKA telescope to keep pace with technological developments as they arise. 

Yes, they are. In December 2019, the six-year detailed design work involving hundreds of experts at the SKAO Global Headquarters and in partner institutions around the world culminated with the completion of the overall System Critical Design Review, which was preceded by critical design reviews for each of the SKA’s elements. There may still be small changes or refinements if required, but we don’t expect major changes to the agreed designs.

You can read more about the international effort to design all the components of the SKA telescopes here.

They certainly have, as is common with projects of the scale of the SKA project. It was first conceived in the 1980s with a vision of what the next generation telescope should be like and what kind of science questions it needed to answer. An initial design was developed to realise that vision, in a similar way that an architect will come up with a concept or plans to build a house.

This served as a working basis from which to refine the design of the telescopes that would fit within a set budget while having the ability to achieve the game-changing science set out initially.

The science case has also evolved substantially in the last 20 to 30 years as the enthusiasm of the science community into the SKA project has grown and as new discoveries have been made, and the SKAO science case now covers pretty much all areas of astrophysics; all of this has in turn informed the final design for the SKA telescopes.

The engineering process behind that refinement involved consultation with representatives from the science and engineering community worldwide and advice from experts from world-leading astronomical facilities. This has meant the look of the SKA dishes and antennas – and the design of the associated hardware and software that are also essential – has evolved over time.

Such a process is common practice in projects of the scale of the SKA and other examples in astronomy in the recent past include the ALMA telescope, the Very Large Telescope (VLT), and the LOFAR telescope.

Absolutely! The first phase of the SKA’s low-frequency array, to be built in Western Australia, will be eight times more sensitive and 135 times faster than LOFAR, the best radio telescope at these frequencies.

The first phase of the mid-frequency array, to be built in South Africa, will be almost five times more sensitive and 60 times faster than the Karl G. Jansky Very Large Array (JVLA) in the USA, currently the state-of-the-art in the radio domain!

These figures set the scene for a number of fundamental discoveries which scientists are already discussing for when the telescope comes online. And remember, a future expansion would vastly increase these capabilities.

The scale of the data that the SKA telescopes will generate is enormous, and that has required substantial technology development particularly in Big Data and ultra-fast computing.

An average of 8 terabits per second of data will be transferred from the SKA telescopes in both countries to Central Processing Facilities (CPFs) located at the telescope sites. This is approximately 1,000 times the equivalent data rate generated by the Atacama Large Millimeter/submillimeter Array (ALMA), a joint European/US/East Asia facility in the Chilean Andes and currently one of the most productive telescopes working in the microwave/radio regime of the electromagnetic spectrum.

For each of the SKA telescopes, the data will travel along hundreds of kilometres of fibre-optic cables to high-performance supercomputers called Science Data Processors (SDPs), to be located respectively in Perth and Cape Town. To process this enormous volume of data, the two SDP supercomputers will each have a processing speed of ~135 PFlops, which would place them in the top three of the fastest supercomputers on Earth as of 2022. The data will then be distributed to an alliance of supercomputing facilities around the world called the SKA Regional Centre (SRC) network, that will act as the final interface with the science users providing them the science-ready data products they will then be able to analyse.

In total, the SKAO will archive 710 petabytes of data per year. This would fill the data storage capacity of about 1.5 million typical laptops every year by today’s standard.

The SKA is a €2bn project (in 2021 €), comprising: a construction cost for two world-class telescopes of €1.3bn, and €0.7bn for the first 10 years of operations (2021-2030). 

Funding comes from the SKAO member states.

The SKA project is an international endeavour. In addition to the SKA Observatory's member states, institutions in many other countries have contributed, and continue to contribute, to the design and construction effort. Construction at the telescope sites is being coordinated by the SKAO in partnership with Australia's CSIRO and South Africa's SARAO, which operate the respective observatory sites in each country.

Read more on the countries involved in the SKA project and their contributions here.

Once completed, the SKA telescopes are expected to be operational for more than 50 years. This is the typical lifetime for such facilities, and includes new instrumentation, software development programmes and other upgrades to maintain the world-class aspect of the telescope during its lifetime. It is hard to predict what the SKA telescopes will look like in 50 years, but one thing is for sure: they will have transformed our understanding of the Universe and will be an integral part of humanity’s popular culture!