The powerful Chinese megawatt laser ‘small enough for a satellite’
- Chinese team says its 1.5kg pulse device is possible because of breakthroughs allowing critical components in solid state lasers to be much smaller
- A laser scientist with the Chinese Academy of Sciences says the device is not a weapon – but a larger version in future could be
A Chinese team said it had developed a small but powerful laser device that could be used on a satellite, but would only be deployed for non-destructive purposes.
The device could be used in a wide range of applications, including identifying a target, tracking, imaging and high-speed communication, said project lead scientist Liu Chong, of the college of optical science and engineering at Zhejiang University, in a paper published in the domestic peer-reviewed journal Aerospace Shanghai last month.
The device can generate a powerful 1 megawatt laser light and can fire 100 shots per second for nearly half an hour without overheating in a space environment, according to its developers.
The pulse laser device – which is about the size of a 500ml (16.7 fluid ounce) can – could fit in a small satellite and weighs less than 1.5 kilograms (3.3 pounds), including the power source.
The US military plans to launch its own 1 megawatt laser weapon to space next year.
Unlike the Chinese device, which splits a laser beam into short pulses, the US space weapon would produce a continuous wave of light that could direct much more energy to the target.
The US laser weapon could weigh about 4 tonnes but the entire system would need a rocket as big as the SpaceX Starship to launch. It could shoot down a hypersonic weapon in seconds, according to the US Missile Defence Agency.
A laser beam produced by Liu’s device lasted just 5 nanoseconds. It could permanently blind humans or vaporise the surface of certain materials, but its energy – about 5 millijoules per shot – was not high enough to take down a missile or satellite.
However, the intense laser pulse could help detect a distant threat, track its movement precisely and take images of the target with an unprecedented level of detail, according to the researchers.
Two Chinese satellites equipped with the megawatt laser could also establish a “handshake” for high-speed communication using light, even if they were far from each other.
High-powered laser systems are usually bulky, heavy and produce a lot of heat, according to Liu and his colleagues. The heat could affect the performance of some critical components, such as crystals, and reduce the laser beam’s quality.
Liu’s team said recent technological breakthroughs had dramatically reduced the size of some critical components in solid-state lasers.
They had also developed a new cooling device made of copper and indium to efficiently absorb the excessive heat. China has the most reserves of indium, a rare earth element, in the world.
Ground test results suggested the device was ready for space missions, the paper said.
It was unclear when the laser would be put on its first flight. Liu and his collaborators at the Shanghai Radio Equipment Research Institute, a state-owned contractor for space programmes, could not be reached for comment.
A laser scientist with the Chinese Academy of Sciences in Beijing said the device was not a directed energy weapon.
“But a bigger version can be,” said the researcher who asked not to be named because he was not authorised to speak to the media.
He said a pulse-laser weapon could generate shock waves capable of tearing apart metal or composite materials on a fast-moving target. A cloud of electrically charged particles produced by the pulse energy could also damage sensors in a missile’s guiding system.
Unlike the continuous wave laser, which must keep on its target for a long period to be effective, the pulse laser weapon could cause damage almost instantly, according to the Beijing-based laser scientist.
While the beam of a continuous wave laser weapon weakened quickly in the atmosphere, especially in cloudy or foggy weather, the pulse laser beams could penetrate the air much more efficiently and reach targets in lower altitudes, he added.
The US has imposed strict sanctions on China’s laser technology. But in recent years China has caught up to or surpassed the US in some important areas, including pulse lasers.
In a recent experiment conducted in Xian, in northwestern Shaanxi province, Chinese scientists showed a new laser surveillance technology that would allow them to use a small telescope on the ground to take images of a satellite passing over China, achieving millimetre-level detail.
This breakthrough would not only allow China to obtain sensitive technical information about the satellite, but also valuable intelligence such as the area it was looking at, according to the scientists involved in the project.