The making of a space junk disaster? China’s low-cost microsatellites may lead to ‘space pollution’, say experts
There are now nearly 1,400 satellites orbiting the earth and the number could more than double in next five years
Chang Guang Satellite Technology, a private space start-up in Changchun, Jilin province, released a series of high-definition satellite images last month that zoomed in on foreign military facilities such as Japan’s naval headquarters, US aircraft carriers, Edwards Air Force Base in California and Area 51 weapons testing grounds in Nevada.
It was the first time such images had been released in China and they went viral on mainland social media.
The images were taken by JLCG-1, a microsatellite constellation launched last year consisting of four satellites, the smallest of which weighs just 65kg, able to take photographs at resolutions of up to 0.72 metres per pixel.
The JLCG constellation orbits 650km above the earth, slightly above the International Space Station. But the satellites have limited orbital manoeuvrability, meaning that if they enter into a collision course with the space station or other spacecraft in the busy lower-earth orbit, their operator would be unable to move them out of the way.
The number of satellites orbiting the earth has jumped 40 per cent to nearly 1,400 since 2011, and in five years the number could more than double, according to some space industry estimates. The increase has mainly been driven by technological innovations with have reduced the size of satellites, in some cases down to something the size of a smartphone.
In June, US aviation giant Boeing filed an application to the US Federal Communications Commission to launch nearly 3,000 satellites to provide broadband internet services, which prompted traffic jam concerns in the US as no single federal government agency had the means or authority to track a microsatellite and order it to move out of the way to avoid a collision.
The situation in China “could be worse”, said Dr Liu Jing, deputy director of the Space Debris Monitoring and Application Centre, a space environmental protection watchdog under China’s National Space Administration.
US satellite makers such as OneWeb recognised the risk of space debris and had taken steps to address the issue, she said.
Chang Guang, founded two years ago by more than 40 institutional or private investors with technical support from the Chinese Academy of Sciences, is one of many microsatellite and nanosatellite assembly plants to have emerged in China in recent years.
Others include the Shanghai Engineering Centre for Microsatellites, the Picosat Development Centre in Zhejiang, the Shaanxi Engineering Laboratory for Microsatellites in Xian, and the Aerospace Dongfanghong Development company in Shenzhen, each with plans to send tens or even hundreds of small satellites into space.
China remains a relatively small player at present, with international companies such as Boeing, Airbus, SpaceX and OneWeb planning to launch thousands of microsatellites in the coming years which could provide earth-observation or communication services, such as Wi-fi access, to everyone on the planet.
But China could easily catch up in numerical terms because it is building satellites more cheaply, some costing less than a small car. To reduce costs, most Chinese microsatellites do not have rocket engines that need fuel. They also operate in higher orbits to prolong their lifespan.
Large international companies tend produce satellites with rockets that operate in lower orbits due to concerns about collisions and the creation of debris.
China could pollute space with a large number of small, cheap satellites according to some space environment experts, unless the industry is reined in with strict, clear regulations as quickly as possible.
In March, Japan lost contact with Hitomi, its brand new, flagship X-ray telescope. Investigators found the satellite had disintegrated, typically what happens after a space debris collision.
How to regulate traffic in space as the number of satellites increases has been an international concern for decades, but the issue became urgent in recent years.
OneWeb microsatellites are equipped with thrusters that can send them back into the atmosphere to burn up at the end of their service, but Liu said most Chinese microsatellites were not up to that standard and were left drifting freely in space after the end of their operational life. Some were small and operating in high orbits, eluding detection by ground-based radar and posing a severe threat to other spacecraft.
The State Administration of Science, Technology and Industry for National Defence had issued a regulation on small satellites to address such issues, but in practice the regulation was ignored.
She urged the central government to immediately raise the bar for microsatellite standards, requiring them to be equipped with mobility thrusters, among other control devices, and restricting their operations to certain low-earth orbits to shorten the time they lingered in space after service and reduce the chance of collisions with other spacecraft.
But a representative of a private company in Guangdong that plans to send a couple of microsatellites into space in November opposed such restrictions, describing space debris concerns as an “unfounded scare”.
Tens of thousands pieces of debris were currently orbiting the earth, he said, but space was enormous. He likened the situation to “adding a few grains of salt to a lake”, which made no difference.
The microsatellite industry in China was still in its infancy, he said, and its development needed support. Too many restrictions would kill the business, he said, requesting anonymity both for himself and his company. He added that the space debris scare had been invented by the owners of big satellites.
“Of course they don’t want to see the revolution of microsatellite technology which will allow new, small players to challenge their monopoly,” he said. “They will use or fabricate any excuse to suffocate our development.”
New restrictions and regulations would increase the cost of Chinese-made microsatellites, reducing China’s competitive edge in the international market, he said, adding that would be a “betrayal” of China’s national interests.
Pioneering space debris researcher Donald Kessler, a former Nasa astrophysicist, said adding a few thousand satellites in orbit was just the start of the issue.
If the objects in low-earth orbit reached a high enough density, debris generated by one collision would lead to another and eventually fill space with small, fast-flying junk, making all space activities impossible, a scenario known as the Kessler syndrome.
“A 10 to 100kg satellite colliding with a satellite as large as 100,000kg would produce an amount of debris similar to either of the catastrophic collision events that have occurred, i.e., the 2007 China anti-satellite test and the 2009 Iridium-Cosmos collision,” he said.
“If these microsatellites are part of a constellation, a failed microsatellite would eventually collide with another member of the constellation, resulting in a Kessler syndrome effect within the constellation, perhaps quickly expanding to the population of larger objects.”
To mitigate the problem, an international Inter-Agency Space Debris Coordination Committee had imposed a “25-year rule” which required any object placed into earth orbit be out of orbit within 25 years of the end of service.
Kessler said China was a member of the committee and should ensure its launches followed its guidelines.
China has more than 100 satellites in space, with mainland media reports saying space debris warning authorities issued 87 red alerts for extremely close encounters with space debris last year.
The JLCG-1 constellation will end its operational life by 2020, when the Chinese Space Station is due to start operation.