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A dead Soviet satellite and the body of a discarded Chinese rocket rushed toward each other in space this week, but avoided a catastrophic accident Thursday night.
LeoLabs, a company that uses radar to track satellites and debris in space, He said on Tuesday it was monitoring a “very high risk” conjunction: an intersection in the orbits of the two objects around Earth.
The company has used its radar arrays to observe each of the two objects as they pass overhead three to four times a day since Friday.
The data suggests that the two large pieces of space debris were lost by 8 to 43 meters (26 to 141 feet) at 8:56 p.m. ET Thursday.
On Wednesday, when the estimated failure distance was just 12 meters (19 feet), LeoLabs calculated a 10 percent chance that the objects would collide.
That may sound low, but NASA routinely moves the International Space Station when the orbiting lab faces only a 0.001 percent (1 in 100,000) or more chance of colliding with an object.
Since the Soviet satellite and the Chinese rocket body are extinct, no one could separate them from each other. If they collided, an explosion roughly equivalent to the detonation of 14 metric tons of TNT would have sent pieces of debris flying in all directions, according to the astronomer. Jonathan McDowell.
But when the rocket body passed through a LeoLabs radar just 10 minutes after the conjunction, there was only one object there: “no sign of debris,” the company tweeted.
“Bullet dodged”, McDowell He said On twitter. “But space debris is still a big problem.”
A collision probably wouldn’t have posed a danger to anyone on Earth, since the satellites are 991 kilometers (616 miles) above the ground and crossed over the Weddell Sea in Antarctica. But the resulting cloud of thousands of spacecraft fragments would have been a hazard in Earth’s orbit.
Experts at The Aerospace Corporation had calculated much lower collision probabilities – just 1 in 23 billion as of Thursday morning – and the objects were projected to lose each other by about 70 meters (230 feet).
“The space debris community is constantly warning about all these close approaches, and we are not wrong or lying about this,” Ted Muelhaupt, who oversees space debris analysis for The Aerospace Corporation, told Business Insider.
“Any of them is a low probability event, because the space is still very large. But when you take these objects and mix them, sooner or later you will see a payoff. According to most of our models they are delayed by another major collision.” .
Space collisions create high-speed hazardous debris clouds
Nearly 130 million bits of space junk currently surround Earth, coming from abandoned satellites, spacecraft that broke down, and other missions. That debris travels at roughly 10 times the speed of a bullet, which is fast enough to inflict disastrous damage to vital equipment, no matter how small the pieces are.
Such a hit could kill astronauts on a spaceship.
Collisions between pieces of space debris make the problem worse by breaking objects into smaller pieces.
“Every time there is a big collision, it is a big change in the LEO [low-Earth orbit] environment, “Dan Ceperley, CEO of LeoLabs previously told Business Insider.
Two events in 2007 and 2009 increased the amount of large debris in low Earth orbit by about 70 percent.
The first was a Chinese test of an anti-satellite missile, in which China blew up one of its own weather satellites. Then two years later, an American spacecraft accidentally collided with a Russian one.
“So now there is a kind of belt of rubble,” Ceperley said.
India conducted its own anti-satellite missile test in 2019, and that explosion created roughly 6,500 pieces of debris larger than a draft.
The satellite that blew up India had a mass of less than a metric ton.
Combined, the Soviet satellite and the Chinese rocket body that just passed side by side have a mass of nearly three metric tons (2,800 kilograms). Given those large sizes, a collision could have created a significant cloud of hazardous debris.
High-risk satellite conjunctions are becoming more common
This is not the first time that LeoLabs has alerted the world to the possibility of a conjunction of high-risk satellites. In January, the company calculated a possible collision between a dead space telescope and an old US Air Force satellite.
The objects did not collide, but Ceperley said that because both satellites “were dismantled, basically no one was watching them closely.”
The US Air Force, which tracks satellites for the government, did not notify NASA of that potential collision, the space agency told Business Insider at the time.
Expert warnings about space debris have only gotten more urgent since that near miss.
“We are seeing a decided increase in the number of conjunctions recently,” Dan Oltrogge, an astrodynamicist researching orbital debris at Analytical Graphics, Inc., told Business Insider.
Oltrogge uses a software system that has been collecting and evaluating conjunction data for the past 15 years. The recent increase in orbital encounters, he added, “appears to be very well aligned with the new large constellation spacecraft that has been launched.”
The large constellations he refers to are fleets of Internet satellites that companies like SpaceX, Amazon and OneWeb plan to launch. In total, the companies plan to launch more than 100,000 satellites by the end of the decade. SpaceX has already launched nearly 800 new satellites into Earth’s orbit since May 2019.
A debris disaster could cut off our access to space
If the space debris problem were to become extreme, a chain of collisions could spiral out of control and surround Earth in an impassable field of debris. This possibility is known as a Kessler event, after Donald J. Kessler, who worked for NASA’s Johnson Space Center and calculated in a 1978 paper that it could take hundreds of years for such debris to clear enough to to make space flight safe again.
“It’s a long-term effect that takes place over decades and centuries,” Muelhaupt told Business Insider in January. “Anything that produces a lot of debris will increase that risk.”
The sheer number of objects in Earth’s orbit may already be having an effect similar to Kessler’s, a risk that Rocket Lab CEO Peter Beck outlined last week.
“This has a massive impact on the launch side,” he told CNN Business, adding that the rockets “have to try to make their way through these. [satellite] constellations “.
This article was originally published by Business Insider.
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