Starlink breaks space traffic safety rules and China may follow: study
- Chinese researchers say SpaceX’s newest satellites are ignoring unwritten but commonly accepted 10km distance rule
- They urge China to follow suit and develop its own safety limit or risk giving the US an upper hand
The researchers said two of Starlink’s newest satellites, equipped with high-speed laser communication devices, came within 4.9km (3 miles) of each other on June 30. The commonly accepted – if unwritten – minimum distance to avoid collision is 10km (6.2 miles).
In a study published by Chinese peer-reviewed journal Radio Engineering, the researchers said the unusually dense formation was no accident, but the result of a complex scheme by SpaceX to maximise the performance of its laser communications.
The technology requires the sending and receiving devices to stay within a straight line of sight over a certain distance, they said. Nor was it the only example of Starlink satellites ignoring the accepted traffic rule, the researchers found.
Yu Shunjing, a satellite design engineer with China’s largest manufacturer of the devices DFH Satellite Co, and his co-authors said the rapid development of large-scale constellations “will make space, especially the lower Earth orbits, very crowded”.
“We must establish a new ‘space traffic rule’ based on new technologies, otherwise the development of Chinese constellations will be seriously restricted,” they said.
A Beijing space scientist who was not involved in the study warned a change in the minimum distance could increase the risk of a collision in Earth’s lower orbit.
While active collision avoidance systems could reduce the risk of accidents, “even the best technology can fail sometimes”, said the researcher, who asked not to be named because of the issue’s sensitivity.
Five kilometres may provide plenty of room on the ground but a satellite can cover that distance in half a second, he said.
“The existing safety limit is based on scientific calculation. Crossing the line could lead to some dangerous consequences, because one collision can lead to another.”
China is keeping a close watch on SpaceX’s commercial satellite programme, which provides internet access to civilian and military users, and this is not the first time Chinese scientists have voiced their concerns.
After observing Starlink’s role in supporting Ukraine’s internet communications during the Russian invasion, a group of Chinese military researchers in May urged Beijing to develop the capability to destroy the network if necessary.
China’s military warns US could dominate space with Starlink satellite network
When completed, Starlink will consist of tens of thousands of satellites, a network that conventional anti-satellite weapons such as missiles will not be able to destroy entirely.
But Starlink’s early infrastructure has a problem: it needs ground stations to pass data from one satellite to another, or signal-relaying ships when the devices are flying over the oceans.
These facilities not only increase operational costs and limit bandwidth, they can also become vulnerable targets in a war.
The new generation of satellites launched by SpaceX in September last year is an attempt to overcome these problems, by using laser beams to communicate directly with each other.
Plan for 30,000 Starlink satellites sparks crash concerns at Nasa
A year later, more than 1,400 laser satellites are now circling the planet, with 880 in active service and providing high-speed communications to some parts of the globe, according to the Chinese study’s estimates.
Yu’s team said high-resolution radar images suggested that each satellite is carrying several laser transmitters pointing in different directions, allowing them to establish communications with similar devices in the same or nearby orbits over a distance of up to 2,500km.
The researchers said SpaceX is putting these satellites into closely neighbouring orbits to increase communications coverage and lessen signal interruptions, with collision avoidance clearances far below the generally accepted threshold.
SpaceX has been approached for comment on the study’s claims.
China’s rocket break-up sends space junk flying near Starlink orbit
China has established its own global laser communications network with its BeiDou navigational system and other satellites, and is also building a commercial communications network – with considerably fewer satellites than Starlink – to provide high-speed internet access across the planet.
Chinese space authorities plan to extend the high-speed laser communications service from Earth to the moon over the next few years.
Last year, the Chinese government filed an official complaint to the United Nations, accusing two Starlink satellites of coming dangerously close to its Tiangong space station, forcing the three astronauts on board into an emergency manoeuvre to avoid collision.
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The US government denied the charge, blaming China for failing to provide data on the Tiangong’s position.
Meanwhile, SpaceX is planning to carry out the first commercial spacewalk in March next year, with a high-definition live stream to demonstrate the power of laser communications technology.
The Polaris Dawn spacewalk will take place at an altitude of 700km, at a higher orbit than the Chinese and international space stations.
