Thousands of active satellites orbit the Earth at any given time. However, there are millions more of potentially hardware-threatening debris scattered in the same space; a conversation re-popularized when a SpaceX Starlink satellite nearly collided with the European Space Agency’s Aeolus satellite.
In a Tweet sent out Monday by the ESA, they told that they had to fire the thrusters on its Aeolus satellite to avoid colliding with a satellite in the SpaceX Starlink constellation.
“Experts in our #SpaceDebris team calculated the risk of collision between these two active satellites, determining the safest option for #Aeolus would be to increase its altitude and pass over the @SpaceX satellite,” the agency tweeted via its ESA Operations account.
“The maneuver took place about 1/2 an orbit before the potential collision. Not long after the collision was expected, #Aeolus called home, as usual, to send back its science data – proving the maneuver was successful and a collision was indeed avoided.”
The ESA says it performed 28 collision avoidance maneuvers across its fleet in 2018 but further on indicated that it was the first time it has had to move a satellite to avoid colliding with another active satellite, much more one from a mega-constellation.
“The vast majority of ESA avoidance maneuvers are the result of dead satellites or fragments from previous collisions,” the ESA said.
The space agency went on to warn that as Starlink and other satellite constellations grow to hundreds or thousands of satellites, manually avoiding collisions “will become impossible.”
ESA added that it’s working on automating the process of collision avoidance using artificial intelligence.
No harm was done and the ESA was successful in making its avoidance maneuvers. However, it inspired a particular conversation about how we deliver and dispose of satellites on the Earth’s orbit.
“There are no rules in space,” Holger Krag, Head of ESA Space Debris Office, says. “Nobody did anything wrong. Space is there for everybody to use. Basically, on every orbit, you can encounter other objects. Space is not organized. And so we believe we need technology to manage this traffic.”
Contrary to the fact that space is a vast expanse, the orbits around the Earth itself are not inexhaustible. There are now well over an estimated million pieces of space debris larger than 1 centimeter in orbit around Earth. Each one has the potential to collide with and destroy another satellite, creating hundreds of thousands of more pieces of space debris.
Collisions between satellites are not completely out of the ordinary. As more and more satellites are sent out to space, the higher the chance that a collision is bound to happen. One of the most famous satellite collisions was between the US Iridium 33 satellite and the defunct Russian Kosmos-2251 satellite in 2009, which resulted in thousands of pieces of debris.
That 2009 collision contributed to half of the current space debris along with the 2007 anti-satellite test in which China blew up a satellite of its own with a missile.
Many have noted that the current policies we have about “space littering” is not adequate and will be easily overwhelmed as commercial companies are developing their own technologies and are sending out satellites by the thousands.
Elon Musk’s SpaceX alone is currently working to creating a mega-constellation of its Starlink satellites to orbit around the planet to be able to provide global broadband access.
All together, SpaceX alone plans to launch a total of 12,000 Starlink satellites into orbit in the coming years.
Addressing the issue, ESA proposes a program called Space Safety, which will aim to create a protocol on how commercial space companies and agencies are required to remove their respective space debris.
Primarily, the ESA Space Safety proposal demonstrates that removing space debris is possible. Then it lobbies for international space law to be changed to say that a satellite’s owner must de-orbit the craft at the end of its mission. If the owner fails to do this, they have to pay an industrial contractor to go and remove the satellite for them.
The ESA is hoping that because of this policy, it may help emerge a new market that would solidify the concept into real-life application.