Two pieces of space debris passed very close to each other, but escaped a collision, said a company that uses radar to track objects in orbit.
LeoLabs said a deactivated Russian satellite and a dropped Chinese rocket segment would likely pass 25 meters from each other.
According to the company, there were no signs of debris over Antarctica early on Friday, October 16, suggesting that there was no shock.
Other experts estimated that Kosmos-2004 and the ChangZheng rocket stage would pass much further away.
Since the objects have a combined mass of more than 2.5 tonnes and a relative speed of 14.66 km / s (32,800 mph), any collision would have been catastrophic and produced a rain of debris.
And given the altitude of almost 1,000 km, the resulting fragments would have remained in orbit for an extremely long time, posing a threat to operational satellites.
LeoLabs, a Silicon Valley start-up, offers orbital mapping services using its own radar network.
Moriba Jah, an astrodynamicist at the University of Texas at Austin, in the United States, calculated the distance between the two objects to be 70 m.
And Aerospace Corporation, a highly respected consultancy, came to a similar conclusion.
With more and more satellites being launched, there is growing concern about the potential for collisions.
The major concern is the growing population of redundant hardware in orbit – about 900,000 objects larger than 1 cm in some counts – all of which are capable of causing immense damage, or even destroying, an operational spacecraft in a high-speed encounter.
This week, the European Space Agency released its annual report on the state of the space environment, highlighting the continuing problem of fragmentation events.
This includes orbiting explosions caused by surplus energy – in fuel and batteries – aboard old spacecraft and rockets.
On average, in the past two decades, 12 accidental fragmentations have occurred in space each year, “and this trend is unfortunately increasing,” the agency said.
Also this week, at the online International Astronautics Congress, a group of experts listed what it considered the 50 most abandoned objects in orbit of most concern.
A large proportion of them were ancient Russian Zenit rocket stages or from the times of the Soviet Union.
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