China on Tuesday alleged that US billionaire Elon Musk-owned SpaceX’s satellites had two “close encounters” with its space station in orbit, and has complained to the UN about the incidents which endangered the safety of the Chinese astronauts.
Chinese Foreign Ministry spokesman Zhao Lijian, addressing a media briefing here, said that the Chinese space station was forced to avoid collisions with satellites launched by Musk's Starlink Internet Services project.
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“I can confirm in July and October this year SpaceX satellite links made close encounters with China’s space station twice,” Zhao said.
During this period, the Chinese astronauts were executing missions in the Space Station (CSS), he said, replying to a question.
“Out of security reasons, the Chinese space station adopted preventive collision avoidance control measures,” he said.
Zhao said China has complained to the UN Secretary on December 3 about the SpaceX satellites’ close encounters under the principles of Outer Space Treaty, warranting the signatories to report any violations to protect the lives of astronauts.
He said that under the treaty, the parties should bear the international responsibility for the activities in outer space whether by governmental or non-governmental entities.
The incidents occurred on July 1 and October 21, according to a document submitted by China this month to the United Nations Office for Outer Space Affairs, according to media reports.
Accusing the US of ignoring its obligations under the treaty posing a severe threat to the astronauts, Zhao urged Washington to take measures to prevent such close encounters from happening again and “act in a responsible manner”.
The CSS “Tiangong” has stayed in a near-circular orbit at an altitude of around 390 kms above the earth since it was launched on April 29.
Since its launch, China has sent two batches of three astronauts to build the under-construction CSS which was expected to be ready by next year.
In October, China sent three astronauts, including a woman.
Billed as the most prestigious and strategically important space project for China, the low orbit space station would be the country's eye in the sky, providing round the clock bird's-eye view on the rest of the world.
Once ready, China will be the only country to own a space station while the ageing International Space Station (ISS) of Russia is a collaborative project of several countries.
CSS is expected to be a competitor to the ISS and perhaps may become a sole space station to remain in orbit once the ISS retires.
The Hong Kong-based South Morning Post reported that from May 16 to June 24, the Starlink-1095 satellite maintained a steady descent from its original 555 km-altitude orbit to around 382 km, and then stayed there, posing the risk of a potential collision with CSS.
Following this, the CSS was forced to conduct an evasive manoeuvre on July 1 when the two-spacecraft had a close encounter, according to China’s note posted on the website of the UN Office for Outer Space Affairs.
The other satellite, the Starlink-2305, similarly continuously changed its orbit in October with an “unknown” manoeuvre strategy and unassessable orbital errors, again forcing the CSS to implement collision-avoidance control, it said.
According to satellite tracking information, Starlink-1095 continued to descend until it re-entered the atmosphere and burnt out in September, while the Starlink-2305 climbed from a 350 km orbit to 550 km from October to November.
When two spacecraft are orbiting at the same height, there is a risk of crossing paths and collisions, the report said.
US entrepreneur Musk is the founder-CEO of SpaceX (Space Exploration Technologies), which operates the Starlink internet satellites and has already sent more than 1,900 satellites into space since 2019.
SpaceX has said that its Starlink satellites are equipped with autonomous orbit changing features to avoid collisions, and that other spacecraft do not need to manoeuvre in case of an encounter, the Post report said.
In March, SpaceX signed an agreement with US space agency NASA promising to steer Starlink satellites out of the way if they got too close to the ISS or other Nasa spacecraft.
It also agreed to launch its satellites into initial orbits that did not come within three miles (5 km) of the ISS or other Nasa spacecraft, according to the Post report.
Apart from SpaceX, other commercial companies have also announced plans to further populate space with their own internet service constellations, including Amazon, OneWeb and Telstar.
