South Africa’s MeerKAT radio telescope array will be ready to start scientific observations by the end of next month, South African Science and Technology Minister Naledi Pandor announced at last month’s Third SKA African Partner Countries Ministerial Meeting. By then, 21 antennas would be mounted and ready.
“This is excellent progress,” she affirmed. MeerKAT, which will have 64 dish antennas when completed, is intended to be both a major astronomical instrument in its own right and a precursor to the international Square Kilometre Array (SKA) radio telescope, the core elements of which will be cohosted by South Africa and Australia, and which will be the world’s biggest radio telescope. From 2005 to the end of March this year, South Africa had invested some R2.4-billion in the SKA and MeerKAT programmes, including the KAT-7 prototype array of seven dishes.
As for the SKA itself, SKA South Africa (SKA SA), the local organisation responsible for KAT-7, MeerKAT and the country’s involvement in the SKA itself, has been authorised by South Africa’s Ministers of Finance and Science and Technology to start buying land for the core site of SKA Phase 1. “These purchases are subject to negotiation,” reported SKA SA director Dr Rob Adam at the Third SKA African Partner Countries Ministerial Meeting. “We will certainly be ready for construction, to begin in 2018.”
During Phase 2 of the SKA programme, outstations will be set up in a number of other countries. The SKA African partner countries will each host at least one outstation. These countries are Botswana, Ghana, Kenya, Madagascar, Mauritius, Mozambique, Namibia and Zambia. South Africa and the eight SKA African partner countries are also partners in the African Very Long Baseline Interferometry Network (AVN), being developed under the leadership of SKA SA with South African expertise. At the Ministerial Meeting, a memorandum of understanding for institutionalising cooperation in radio astronomy (including the SKA and AVN) between South Africa and the other SKA African partner countries was approved.
BACK ON TRACK
“MeerKAT is going well,” Adam tells Engineering News. “We had some initial hiccups around the quality of the antennas, but that has been ironed out. We have a very good relationship with the manufacturer, but there was a delay in the roll-out. However, we’re now back on track. Last month, we should have had 21 antennas up – we had 20. Now, they’re going up at a rate of one a week.”
At the end of April, using four antennas, MeerKAT obtained its first image of a pulsar. This was important – not in scientific terms but with regard to the design, development, engineering, construction and operation of the instrument. “It showed we’re on the right track,” he notes. “We’re going flat out to have a scientifically competitive array by the end of June. This will initially use 16 antennas, even though more than 21 will have been erected by then. After an antenna has been erected, it must be calibrated and then integrated into the array. It can’t just be switched on and put to use. By the end of this year, we’re targeting a 32-dish array,” he reports. “That would make MeerKAT the largest array of its type in the world. It would be larger than the 27-dish [Karl G] Jansky [Very Large] Array in New Mexico.”
This month sees the holding of a MeerKAT Science Workshop. While the various large sky survey projects for the instrument have already been agreed, they will have to be recalibrated and this will be the purpose of the workshop. This recalibration is necessary because MeerKAT’s performance is going to be better than originally planned. “We’ve recalibrated the antennas beyond their specification – they’re more capable than originally intended.”
Meanwhile, what of KAT-7? (KAT stands for Karoo Array Telescope.) This is still operational, although it has been suffering from problems with its receivers. “It being an engineering test-bed, its receivers are not as reliable as MeerKAT’s and there have been some failures,” he explains. “We have been able to repair them with the help of the engineering team at Hartebeesthoek [Radio Astronomy Observatory]. However, this is likely to be an ongoing issue. Ultimately, we may decide to retrofit them with MeerKAT receivers, but, at this stage, this would upset the MeerKAT schedule and we can’t entertain it, at least until MeerKAT has been completed. Thereafter, we would do it on the basis of a recommendation from the scientific community, and taking costs into account.”
SKA SA now employs about 250 people, and should read some 270 at full complement. The development of the organisation has been taking place in phases and a new phase will start once MeerKAT has been completed. “We will then need a strong operating team,” he points out. “With the project team, our idea is that, once MeerKAT is finished, they will start working on SKA Phase 1, which should start then. Hopefully, it won’t be delayed.” The current schedule is that MeerKAT will be operated for five years and then be incorporated into the SKA. “MeerKAT would still be owned by South Africa but would be operated by the international SKA Organisation (SKAO).
“There has been a rebaselining of the SKA, which was agreed in March 2015,” he points out. “The number of antennas was reduced from 256 to 197 for SKA Phase 1. This was partly because of efficiency gains in the technology since the SKA was launched, but also to reduce costs.”
The SKAO has its head office at the famed British Jodrell Bank radio astronomy observatory, not far from Manchester. “As MeerKAT developed and as we gained experience with its development, so the SKAO has been increasingly drawing on our experience. As a result, we’re playing an increasingly strong role in Manchester.”
Currently, one of the main activities of the SKAO is the negotiation of the treaty organisation that will own and operate the SKA. The key players in this process are, however, not the members of the SKAO itself but the governments of the SKA member countries. “The key question,” observes Adam, “is: who pays what? That is being discussed now.” Currently, there are ten countries participating in the SKA – Australia, Canada, China, India, Italy, the Netherlands, New Zealand, South Africa, Sweden and the UK.
As of now, no country has committed funds for the construction of the SKA itself. That step must await the finalisation of the treaty and any associated agreements governing the SKA project and instruments. “We fully expect the funding to come,” he assures. “In Europe, there is a very strong commitment to the SKA. The UK is fully in – they’re probably the biggest. The Netherlands is in. Germany is out at the moment but we expect them to come back. What is less likely is that the US will join. In South Africa, we haven’t wavered in our commitment.”
MeerKAT and, even more so, the SKA, will generate huge amounts of data. As a result, big data has become and will remain a major focus of SKA SA. “That’s where the innovations will come – innovations applicable in many disciplines of science, not just astronomy. The economic impact of the SKA for South Africa will be from big data.”
The original idea behind the AVN was to convert old, large and now obsolete telecommunications dishes in a number of African countries into radio telescopes. This, indeed, is being done. But, as not all the African SKA partner countries have suitable antennas, the concept has now expanded to include the construction of new dishes as well.
“Things are going fine,” reports SKA SA associate director: Africa and Special Projects Anita Loots. “We’re working in a number of countries, at different levels of maturity.” The most advanced project is in Ghana, involving the conversion of a 32-m-diameter dish at Kutunse. “Ghana is close to operational testing, in conjunction with Hartebeesthoek and a radio telescope in Europe. The aim is to show that the Ghana antenna can meet scientific quality standards. We hope to formally launch the [Kutunse] radio telescope in September or October.”
Ghana was chosen as the lead country for the AVN project because it is roughly halfway between South Africa and Europe, making it ideal for the creation of a link between Hartebeesthoek and European radio telescopes to carry out Very Long Baseline Interferometry (VLBI) observations. “Ghana was chosen for scientific VLBI reasons, and Ghana has shown commitment ever since!” explains Adam. Helping accelerate the process was the fact that the country already possessed an institution within which the Kutunse observatory could be placed – the Ghana Space Science and Technology Institute. This means that the country not only already has space-related expertise but also a space-related budget line. Ghana has already appointed a chief scientist for the radio telescope and is busy training personnel, with the assistance of SKA SA and the UK’s Royal Society.
Elsewhere, the institutional frameworks needed to permit and support radio astronomy observatories still have to be established. “The other planned conversion projects are still at various stages in the development of their governance structures, but the feasibility studies have been completed in Zambia, Madagascar and Kenya,” notes Loots. “But they still need to set up the institutions which will run the radio telescopes. We don’t involve our engineers in a project until the governance activities have been completed. Zambia looks likely to be next – they have to relocate a major telecommunications antenna which is currently on the same site as the dish. They have put in a request to their Treasury for a budget to move it. We’re likely to send in the engineers next year.”
The pilot project for newly built dishes will be in Botswana. The great advantage of new construction is that an optimal site can be chosen, whereas, with conversions, the site is fixed despite possible problems like urban encroachment. Radio frequency interference (RFI) campaigns will be carried out in Botswana to determine the best practicable site (that is, one with the least RFI) for the radio telescope. “Botswana is showing a lot of commitment,” she states.
However, the programme to build new radio telescopes in African SKA partner countries has not yet been funded. “We’re discussing a number of funding options,” says Loots. “We need to establish the details of the funding, roll-out, and so on.” The specialists will report back on these issues at the next SKA African Partner Countries Ministerial Meeting, in November.