South China Morning Post:
Chinese astronauts have played many roles in space, including teacher, mechanic and tourist.
But all the science classes, repair missions and spacewalk flag-waving have tended to obscure the fact that they are, first and foremost, members of the People’s Liberation Army.
China’s manned space programme has so far given its astronauts few opportunities to fulfil military roles, but that will all change when its space station is completed in the next six years.
One task on their to-do list could be detecting and tracking nuclear submarines from space, using a technological breakthrough achieved by Chinese scientists.
The two-man Shenzhou XI spaceship that blasted off from the Jiuquan Satellite Launch Centre in Inner Mongolia on Monday morning will soon dock with the Tiangong-2 space laboratory, launched last month, which is carrying the world’s first space-based cold atom clock.
The ultra-accurate timepiece shares its core technology with cold atom interferometers, which can measure tiny changes in gravitational pull with unprecedented sensitivity, and one of the devices, to be built and put on the Chinese space station, could potentially be used to track nuclear submarines.
Nuclear submarines can be massive, with the largest measuring more than 170 metres in length and displacing 48,000 cubic metres of water, and when they cruise several hundred metres below the ocean’s surface they generate many gravitational ripples. An extremely sensitive detector could catch and analyse the invisible ripples to locate and follow the submarine.
Using cold atom interferometry to detect submarines is a controversial technology, with some scientists saying the enormous engineering challenges involved mean it will never work, especially over the long distances involved when using a space-based platform. Others think it’s worth a try.
China could be the first nation to do so, according to a researcher at the Beijing-based China Academy of Space Technology, which has initiated and designed most of China’s space projects.
The cold atom interferometer would be part of a super-cold atom laboratory in the space station’s experimental module, said the researcher, who declined to be named because he was not authorised to speak to the media about the project.
“The technology’s potential military value is not discussed in public, but it’s an open secret in the research community,” he said.
Professor Tu Liangcheng, who has studied the precise measurement of gravity at Wuhan’s Huazhong University of Science and Technology, said the Chinese government had substantially increased funding for submarine detection technology in recent years.
“There is a shift in the navy’s attitude to submarine warfare,” said Tu, who has been involved in military research projects.
In the past, China paid more attention to developing its own submarines and the technology to make them quiet, powerful and able to stay submerged for longer. It largely ignored the activities of other countries’ nuclear submarines, unless they ventured into Chinese waters.
But funding for submarine-hunting technology, including gravitational measurement, had now increased significantly, Tu said.
The change reflects China’s ambition to develop a “blue-water” navy able to protect its national interests along important maritime trade routes spanning the globe.
Tu said the Chinese navy desperately wanted to be able to track foreign nuclear submarines, but it was 30 years behind the capabilities of the United States when it came to submarine-detection technology.
“Now we have enough money, and China’s strength in this field of research in on par with the US and Europe,” Tu said. “But the pressure is high, there is high expectation of a quick breakthrough, and we are short of hands.”…
