Kathy Gibson reports from SATNAC 2014 – While many different sciences are central to the success of the Square Kilometre Array (SKA), the network carrying data around the globe is vital.
“Optical fibre very much forms the backbone of the network,” says Professor Tim Gibbon, department of physics at Nelson Mandela Metropolitan University, addressing delegates at SATNAC 2014 this morning.
The SKA is a big data project that spans South Africa and Australia, with a combined square kilometre collection surface area of the dishes. The enabling optical fibre backbone has a baseline of 3 000km.
The university is researching optical fibre technologies to deliver the best possible network to the SKA, and is currently working on the MeerKAT telescope, which is the precursor to the SKA.
It is also looking at ways to deliver fibre to the home in the African context.
Prof Gibbon points out that NMMU has one of the country’s best-equipped laboratories in terms of fibre research, and collaborates with bodies around the world,
The network architecture for SKA has some points of similarity with traditional networks but also some important points of departure.
For instance, each radio telescope in the MeerKAT project has access to a supercomputer within 10km. The telescopes send their own images to the CPU, which correlates the images to one – much bigger – image.
However, within a few years, the radio telescopes will be spread over a much wider area than 10km, across the Karoo and in the Australian outback.
“We are talking about tremendous data rates,” Prof Gibbon adds. In addition, the central computer needs to send atomic clock messages back to each dish, which have to be synchronised to the picosecond level and will require a supercomputer of its own.
The SKA will have enough optical fibre to wrap twice around the earth. It will be sensitive enough to detect airport radar data from 50 light years away, By 2024 it will generate more than 100-times the current data traffic of the entire
Internet.
A number of different data types will be carried: the science data collected by the radio telescopes and sent to the CPU; the time data from the CPU to the telescopes; and management and administration data.
The optical fibre network also has to meet the challenge of connecting scientists in remote locations; and with the rest of the world.
The SKA is headquartered in the UK and 11 different countries are involved. Construction should begin in 2017 and fully operational by 2024.
The KAT7 radio telescope has already been built, consisting of seven dishes. This will be grown to the 64 dishes of MeerKAT, which will in turn form the basis of the SKA.
“For us it’s a wonderful opportunity to develop our students and uplift the sciences in astronomy, engineering and physics,” says Prof Gibbon.