By THE AFRICA BAZAAR Staff Writers
South Africa is making an important move in the advancement of science on the continent: Building the world’s largest and most powerful radio telescope.
Last month the foundation was laid at the Square Kilometer Array (SKA) site in the Northern Cape for the MeerKAT antenna, a 64-dish radio telescope project that is expected to be commissioned in 2014 or 2015 both as a precursor to the SKA and as one of the most powerful telescopes in the world.
The project, co-hosted by Australia, is part of international effort which includes the U.S. toward collaboration across a broad front to advance cutting-edge radio astronomy projects. The agreement between SKA South Africa and the National Radio Astronomy Observatory (NRAO), a Charlottesville, Virginia-based U.S. federally fund science research and development center, will allow the countries to pool resources and expertise in high-level projects related to the development and implementation of software, data processing and archiving and state-of-the-art receiving systems.
The two institutions will exchange staff and students, hold joint workshops and work on plans to establish joint research and development activities.
“The collaboration agreement renews long-standing ties between SKA South Africa and NRAO and comes at a time when a major push is required in algorithms, software and computing to support the new and upgraded facilities in the U.S. and South Africa,” said Dr. Jasper Horrell, SKA SA’s general manager for science computing and innovation.
The foundation laid last month is the first of 64 similar foundations—each comprising 78 cubic meters of concrete and 9 tons of steel—that will be built for the MeerKAT over the next nine months. The MeerKAT is expected to be operational in 2016.
It will be the largest and most sensitive radio telescope in the southern hemisphere until the Square Kilometer Array is completed around 2024.
“We are talking here of cutting-edge work in high-performance computing and algorithms that is of great significance for radio astronomy worldwide,” said Horrell.
SKA South Africa director Dr. Bernie Fanaroff said that radio astronomy in both countries would benefit from sharing the expertise that had resulted from recent expansions and upgrades to several radio astronomy facilities in the U.S. and the construction of the KAT-7 and the MeerKAT radio telescopes in South Africa. The seven-dish KAT-7 is paving the way for the 64-dish MeerKAT telescope.
“Scientists in the US are keen to collaborate with South Africa in the construction of the MeerKAT telescope as a precursor to the SKA because they recognize that the MeerKAT will be a world leading and very exciting telescope in its own right,” Fanaroff said.
Leading radio astronomy teams from around the globe have already signed up to use the instrument. But first, the design team working on the project with contractors Brink & Heath Civils will have to overcome certain challenges in the process as they develop and design a foundation for the high-tech telescope, which in itself is complex and challenging since it has to meet a set of stringent requirements.
“The foundations must ensure that each of the 19-meter-high antennas with its 13.5-by-16-meter main reflector will be exceptionally stable and able to point accurately at distant celestial objects at wind speeds gusting to 69 kilometers an hour as well as survive wind speeds of up to 144 kilometers an hour,” said Tracy Cheetham, general manager for infrastructure and site operations at SKA South Africa.
Another challenge for the design team is to ensure that each antenna was carefully earthed and would not be damaged in the event of a lightning strike. To meet these stability requirements, each foundation consists of eight steel-reinforced concrete piles at depths of between 5 to 10 meters, depending on the local soil conditions. A square slab of concrete (5.2 by 5.2 meters and 1.25 meters thick) rests on top of the piles to add further stability. The 32 “holding down” bolts are pre-assembled in a circle to form a steel ring cage, or so-called “bird’s nest,” into which the concrete is cast.
“This first foundation will now be verified through a series of load tests to ensure that all specifications have been met,” Cheetham said. “Getting this absolutely right is critically important for the science to be done with this instrument, and will also inform the construction of foundations for other SKA dishes to be built in the Karoo.”
The MeerKAT project has given South Africa the opportunity to not only help the advancement of science on the continent but to also play a key role in encouraging scientific and technology innovation among its youth ,as close to 100 young scientists and engineers are working on the MeerKAT project’s design and technology developments for the SKA.
According to Justin Jonas, a professor and associate director for science and engineering at SKA South Africa, the MeerKAT “will make up one quarter of SKA Phase 1 mid-frequency array, and the science planned for SKA Phase 1 is very similar to the MeerKAT science case—just much more ambitious.
Working in collaboration with South African industry and universities and collaborating with global institutions, the South African team has developed technologies and systems for the MeerKAT telescope, including innovative composite telescope dishes and cutting-edge signal processing hardware and algorithms.
“Our researchers and students who participate in the MeerKAT surveys have a huge advantage. They are well placed to enter SKA Phase 1. They have the opportunity to become science leaders in future SKA projects.”
Located at the engineering office in Cape Town and at universities and technology companies across South Africa and Africa, researchers interact closely with SKA teams around the world to ensure the success of the project.
Constructing of the 64 MeerKAT dishes in the Karoo is expected to continue through 2016, while construction on the 190 dishes of SKA Phase 1 is expected to begin once the MeerKAT is complete.
“The design of the SKA dishes is not yet final, but they should look similar to the Gregorian-offset dish design chosen for MeerKAT,” said Jonas.