“The SKA is a key international scientific research cooperation project of the Belt and Road Initiative,” China Central Television said in a report on August 18.
But to SKAO management and scientists working on the project, this is a new narrative.
“My understanding is that the Belt and Road Initiative is mainly focused on collaboration of regional economic development and transportation with China, and the SKAO is not included in this initiative,” said William Garnier, director of communications, outreach and education.
Wu Xiangping, chief scientist of the SKA China team, underscored the message.
“The SKA has nothing to do with the Belt and Road Initiative,” he said.
“It’s an international cooperation project which was in existence before the Belt and Road Initiative.”
The US was part of the project until 2011. But during the decadal survey to set the astronomy community’s priorities in 2010, “the SKA’s design and cost estimates were very immature, and so there were higher priority projects that sat above it”, SKAO director general Philip Diamond said last week.
As a founding member of the SKAO, China is mainly responsible for developing and delivering a total of 68 state-of-the-art radio dishes by 2027, which involve key technical innovations.
“We required a novel design, called an offset Gregorian, with the receivers sitting at the end of an arm coming from the main structure. The dishes had to be affordable, light but able to point accurately at objects in the sky under significant wind conditions,” Diamond said.
Each dish uses 66 triangular panels to form a three-dimensional hexagonal grid structure, and each triangular panel has a unique curvature, according to its chief designer Du Biao.
“It was a huge challenge to design a system in which the positions of the main reflective panel, the second panel and the receiver need be aligned to an accuracy of less than 1mm,” Du told state broadcaster CCTV last month.
China has been actively engaged in the project since the early 1990s. The idea of the SKA emerged from conversations between scientists around the world as to the next big step in radio astronomy, Diamond said.
A team led by the late radio astronomer Nan Rendong proposed to host the SKA site in China by building a significant number of huge radio dishes in the country’s southwest.
“The design was determined to not fully satisfy the science goals of the SKA community, and was not shortlisted. Only Australia and South Africa were on the shortlist in 2005,” Diamond said.
“China has been an immensely valuable and reliable partner in the SKA Observatory,” he added.
Apart from the dishes in South Africa, China is also playing a major role in developing the signal processing system for the antennas in Australia as well as the so-called SKA Regional Centres, which will provide the science community with access to SKA data.
“FAST is a wonderful instrument and, although only operational for a few years, is already doing excellent science, such as its contributions to the work using pulsars to detect gravitational waves across the universe,” Diamond said.
Meanwhile, the SKAO covers a much wider frequency range, and can produce higher resolution images than FAST, by adopting the so-called aperture synthesis technology.
“However, FAST’s huge sensitivity makes it a superb detection and survey instrument for the SKA telescopes to follow up, and I expect there will be many joint science programmes in the future,” he said.
When the SKA is completed, China will be assigned about 8 per cent of the observation time, which is in proportion to the financial contribution made by individual founding members.
The seven initial member countries of the SKAO, when it was founded in Rome in March 2019, are Australia, China, Italy, the Netherlands, Portugal, South Africa, and the United Kingdom.