Netizens in China criticized entrepreneur and business magnate Elon Musk after satellites launched by his company, SpaceX, under its Starlink program, almost collided with the under-construction Chinese space station twice this year.
There have been multiple such encounters this year, largely due to the increasing number of artificial satellites and the growing volume of space debris.
In a document that China submitted to the UN General Assembly, it claimed that its space station had to implement “preventive collision avoidance control” on July 1 and October 21 this year as it came face-to-face with oncoming Starlink satellites.
Through the written submission, Beijing informed the UN Secretary-General that both these near-collision situations with Starlink satellites posed “dangers to the life or health” of the astronauts who were on board the budding China Space Station that the country began constructing in April this year. The station is expected to be operational between 2022 and 2024.
Elon Musk faced online outrage on the Chinese social media platform Weibo after Beijing took up the matter with the UN. There is already a growing caution by scientists and environmentalists over the congestion of the Low-Earth Orbit (LEO) due to the presence of a large number of satellites and their debris, thereby increasing the risk of collisions.
China began constructing the space station in April with the launch of Tianhe, the largest of its three modules. The station is expected to be ready by the end of 2022 after four crewed missions and will be operational in the next few years.
How ISS Avoided US’ Space Junk
Earlier this month, it was reported that the International Space Station was forced to perform a maneuver to move away from a fragment of a US launch vehicle.
The director-general of Russia’s state space corporation Roscosmos, Dmitry Rogozin, told reporters that the ISS’ orbit dropped by 310 meters for almost three minutes to prevent a close encounter with a particle from the American vessel. The satellite was sent into space in 1994.
Then on 15 Nov, Russia tested its anti-satellite (ASAT) missile on a defunct surveillance satellite called Cosmos 1408. This test shattered the satellite, weighing close to 2 tons, into thousands of pieces.
On November 30, Elon Musk admitted that his company SpaceX’s Starlink program satellites came close to the ASAT debris. This forced a few of the space corporation’s internet satellites to dodge in order to avoid in-orbit collisions.
The weapon test came at a time of heightened tensions between the US and Russia regarding Ukraine and prompted much criticism from the international space community.
It is interesting to note that the Starlink craft themselves have been found to be responsible for over half of all near-collisions in space. Satellites from this company have been noted to be involved in approximately 1,600 close encounters every week.
A close encounter is defined as an occurrence where two craft cross paths within one kilometer of each other.
It is speculated that upon reaching its aim of having a 12,000-strong satellite network, Starlink will be involved in 90 percent of all close approaches. Currently, there are only 1,700 of these craft in space.
Incidentally, around the same time that this Starlink incident was reported, NASA also had to make a change in plans due to space junk. The organization’s officials delayed a spacewalk that was scheduled for two of the agency’s astronauts on November 30, just the night before.
This was a result of alerts that NASA had received regarding nearby space debris that could endanger the crew.
A Major Crash
While the incidents mentioned above are of near-misses, in March this year, a Chinese satellite mysteriously broke apart and scattered into dozens of pieces. In August, a Harvard astronomer noted that it was highly likely that the satellite collided with a chunk of a Russian rocket.
The US Space Force sensors had detected new debris from the Chinese satellite called Yunhai 1-02 in mid-March. The satellite was fairly new and it wasn’t to break down due to regular wear and tear. No other reason for the breakdown was revealed.
Astronomer Jonathan McDowell, however, noticed that the Space Force had updated its space-debris catalog. The change marked object 48078 — a piece of a Russian Zenit-2 rocket that was launched in 1996 — with a note: “collided with satellite”.
Jonathan went through the orbital data and found that the object and the Yunhai satellite passed within a kilometer of each other on the day that the latter broke apart. This collision seems to be the most recent one where two large objects orbiting the earth ran into each other. The last time this happened was in 2009.
These incidents collectively point towards space debris becoming a greater risk for assets and people in space.
The Rising Threat Of Space Debris
The space around Earth is getting more congested by the day. There are around 29,000 man-made objects — all larger than 3.9 inches — that are believed to be circling the planet. A large part of this space junk is in low Earth orbit, within 2,000 km of our planet’s surface.
These objects can be orbiting around at speeds of up to 8 km per second. This makes a collision with even a small piece of space debris dangerous for a spacecraft.
It is quite evident that the amount of debris in space threatens crewed and uncrewed spaceflights alike. In fact, some estimates suggest that the risk of a catastrophic collision of a space shuttle with a piece of junk is 1 in 300.
Scientists have been urging governments to make data related to satellite orbits available so that potential space collisions between these craft at least can be avoided.
Some steps are already being taken to prevent the buildup of debris in space. Several space agencies have been trying to mitigate the problem by following measures such as burning up all the fuel in a rocket stage so it does not explode later, or preserving enough fuel to deorbit a satellite after its mission has come to a close., etc.
The British satellite RemoveDEBRIS, aimed at exactly what its name points towards, was launched in 2018 and deployed from the ISS. It tested two different technologies for removing space debris: capture with a net and capture with a harpoon.
With the continuing militarization of space, there is a greater number of satellites and anti-satellite tests that are adding to the already existing congestion.
On the other hand, another reason for the greater number of satellites reaching into space is the rising demand for internet access. How various countries plan on dealing with this in a sustainable manner remains to be seen.