Reporting by XinZhiyuan
Edit: Peaches
【New Zhiyuan Introduction】Shocking twice, "gravity" was almost staged on the Chinese space station. This year, Musk's Starlink satellite has approached the Chinese space station twice, thanks to the emergency avoidance of China's Tiangong to escape the danger. At present, SpaceX has launched nearly 1900 satellites. And 50% of the world's satellite encounters come from Musk's proud "Starlink Project".
So dangerous, Musk's toy almost became a big killer!
The 2013 sci-fi masterpiece Gravity staged a thrilling scene of a space satellite colliding with a space station.
The terrible thing is that the accident almost happened on the Chinese space station.
Recently, a document shows that the Starlink satellite launched by SpaceX this year has approached the Chinese space station twice.
One on July 1 and the other on October 21.
2 emergency avoidances
For safety reasons, the Chinese space station has implemented preventive collision avoidance control for Starlink satellites.
On 3 December, the Permanent Mission of China to the United Nations (Vienna) sent a note verbale to the Secretary-General of the United Nations:
It was pointed out that the Starlink satellite of the Us Space Exploration Corporation (SpaceX) maneuvered to the orbital height of the Chinese space station several times, and in order to avoid possible collisions, the Tiangong space station had to adjust the orbit twice urgently.
First emergency avoidance
The Starlink-1095 satellite has been operating steadily on an average altitude of about 555 km since April 19, 2020.
From May 16 to June 24, 2021, the satellite continued to de-orbit to an average orbital altitude of 382 kilometers, and remained operating at that orbital altitude.
On July 1, the satellite experienced a close-up event between the Chinese space station.
Starlink-1095 was launched on January 7, 2020, and it has already fallen into the atmosphere on September 20, 2021.
Second emergency avoidance
On October 21, the Starlink-2305 satellite had a close-quarters approach event with the Chinese space station.
Jonathan McDowell, a scientist at the Harvard-Smithsonian Center for Astrophysics, collected the data and found that during the two close encounters, the star chain did not adjust its orbit once, and the other underwent "tiny evasion."
Trend charts for July 1 and October 21
Although the Starlink satellite is equipped with an automatic collision avoidance system, the system does not play a role from the two avoidances of the Chinese space station.
50% of satellite "encounters", SpaceX is responsible
To date, SpaceX has launched nearly 1,900 satellites.
Musk proposed the ambitious "Starlink Plan" in 2015. In the first phase, 12,000 satellites will be launched, and the entire program will launch 42,000 satellites.
Once deployed, these satellites will be able to provide WiFi services to the world and reduce network latency.
According to Musk's original vision:
From 2019 to 2020, large-scale satellite launches will allow about 800 satellites to cover the U.S. mainland;
By 2024, 4,425 small satellites will be deployed in low-Earth orbit.
In addition, SpaceX will deploy more than 7,500 satellites in very low Earth orbits between 335 kilometers and 346 kilometers from Earth.
One of the big questions that was raised at the beginning of the application for the Starlink project was that the large number of satellites had greatly increased the number of spacecraft close-up incidents. At the same time, other satellites need to consume a lot of fuel to avoid it.
At the time, Musk came up with a solution: the satellite built-in "autonomous evasion system" that uses the NORAD database to guide the Starlink satellite to automatically evade all spacecraft.
But what is the result?
According to statistics, more than half of the close contact events between satellites (distance within 1 kilometer) that have occurred since 2019 are caused by Musk's star chain.
As recently as September 2019, the European Space Agency's wind monitoring satellite Aeolus nearly collided with one of SpaceX's Starlink satellites.
Thanks to the space agency's urgent change in the satellite's orbit, the collision was avoided.
SpaceX explained that there was a bug in the satellite software system, and Musk's proud automatic collision avoidance technology did not seem to work at the time.
Hugh Lewis, head of the space research group at the University of Southampton in the United Kingdom, said SpaceX's starlink satellites alone have about 1,600 close encounters with spacecraft every week, accounting for half of all spacecraft events.
Experts predict that once SpaceX completes the first phase of 12,000 satellites, 90% of satellite encounters will involve Starlink satellites.
The number of close encounters between StarLink and other spacecraft | Source: Hugh Lewis
In February 2009, there was the first low-Earth orbit satellite collision in human history, and it is also the most serious known space collision.
At that time, after the collision between the United States' Iridium 33 communications satellite and Russia's long-abandoned space 2251 satellite, more than 500 space debris composed of satellite debris were scattered from an altitude of 490 miles (about 789 kilometers).
Look up at the sky full of "stars"
With so many artificial satellites hanging in the sky, how can we observe celestial bodies?
Now there are only 1900 StarLinks, and if it really reaches 42,000 in the future, what will happen?
These moons are truly "the brightest stars in the night sky", brighter than 99% of the other moons, and astronomical telescopes will show bright stripes, which are very dazzling.
So SpaceX gave a very perfunctory reply, the company has blacked out the bottom of each satellite, but the solar panels are still the same reflective, what a difference.
Each satellite weighs about 260 kilograms and orbits almost 550 kilometers above.
With each launch, the rocket lays like an egg, sending out about 60 starlink satellites.
As human activities expand into space, near-Earth space is becoming more and more crowded. According to estimates, there are now nearly 4,500 satellites in the Earth's orbit, and more than 30,000 fragments.
Schematic of a satellite in geosynchronous orbit
Now the geosynchronous orbit is not only fully occupied, but also the number of satellites registered in the queue internationally has reached more than 2,000.
The number and density of satellite constellations such as Starlink not only greatly affect astronomical observations, but also greatly increase the probability of collisions between satellites.
Some say it would create a lot of space junk that would pose a threat to other satellites in Earth's orbit. If you accidentally hit it, it will explode, producing thousands of fragments.
Each of these pieces of debris could hit other moons, and in the worst case, "Kessler syndrome."
Kessler's phenomenon refers to the fact that when the density of space junk reaches a certain level, it will cause space junk to fill low Earth orbit, making it impossible for human beings to conduct space exploration or even use artificial satellites for hundreds of years.
It also confirms the scene of "Gravity".
Netizens were furious
Musk Starlink angered most Chinese netizens, "Touch the porcelain again, next time take the mechanical arm to catch it and confiscate it!"
There are also people who directly @ Musk, threatening that the road car will not be sold.
It is not easy to believe musk's "for the benefit of mankind".
Some netizens expressed the hope that Musk would be sent to Mars as soon as possible.
"Ma Shen is professional in making space junk, and I hope he will go to Mars soon."
Resources:
https://www.zhihu.com/question/508552825
https://www.zhihu.com/question/508552825/answer/2287982831
https://www.theverge.com/2021/12/28/22857035/china-spacex-starlink-tianhe-space-station-satellites-collisions
https://www.space.com/spacex-starlink-satellite-collision-alerts-on-the-rise
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