If megaconstellations of low-orbiting satellites solve some problems, they will bring new ones.
For his Starlink project, Elon Musk plans to send 12,000 satellites into orbit by 2025. Eventually, the SpaceX company expects to receive authorization to send up to 48,000. The goal is to provide a high-throughput, low-latency satellite Internet connection anywhere in the world at an unbeatable price.
The number of satellites is still standard, when we know that the total number of satellites already placed in orbit by Man was 9,000 so far. In addition, other states and companies want to join the race for high-speed Internet connectivity via the satellite constellation, which adds up to tens of thousands of satellites by the counter.
Megaconstellations, formed by hundreds or thousands of devices, are viewed with suspicion by the scientific community and, in particular, by astronomers. In fact, the initial coating on Starlink satellites tended to reflect sunlight. To the naked eye, it looked like a simple, fast star, but the situation was quite different when it came to observing the sky. In fact, the Starlink satellites were initially extremely bright and left streaks of light in the telescopes’ images, obscuring other stars.
To solve the problem, SpaceX coated its satellites in a dark, non-reflective paint called DarkSat. This has reduced the satellites’ brightness by half, but it’s still not enough to observe the sky properly. Even so, satellites in low orbit and deployed by the thousands tend to come more and more regularly into the telescopes’ field of view as their number increases. Even with DarkSat, they still reflect the sun a lot. This can be particularly disastrous for studying near-Earth asteroids, as they are most visible at sunrise and sunset, which is a good time to practice.
SpaceX doesn’t move and tries to find solutions to the problem to establish a compromise with astronomers. To go further, Starlink satellites have been equipped with a VisorSat. These are types of implantable visors that act as sun visors and for the glowing antennae.
A report from the first SATCON 1 Constellation Satellite Conference offers ten recommendations for companies looking to deploy their devices. In addition to dimming the equipment, it is recommended to orbit at less than 600 km altitude to minimize night reflections, control the orientation of machines, find solutions to avoid light trails in astronomical observation and make satellite coordinates available in real time to scientists.
Another problem that is often observed is the risk associated with the amount of objects present at similar altitudes. This actually increases the risk of collision between different satellites, they would lead to an undesirable chain situation. To prevent this, Starlink satellites are equipped with artificial intelligence thrusters and reflexes to avoid collisions.
However, it happened on several occasions that the satellites of the constellations did not collide. On March 30, rival company OneWeb launched a series of 36 satellites into orbit. The American Space Force had to intervene quickly, because a OneWeb satellite was about 50 meters from a Starlink satellite, very close to each other. Even if the chances of a collision were estimated at only 1.3%, the event would undoubtedly have caused a spectacular chain reaction. Starlink had to manually disable its satellite’s AI in order for the two objects to move away from each other.
A coordination problem therefore arises from now on among the various players in low orbit space, because at the moment it is more often a matter of improvising with each failure. In addition, the increasing number of satellites occupying low orbit can cause problems when launching objects into space, as it will be necessary to go through several layers of thousands of small satellites located at different altitudes.
There would be hundreds of thousands of debris orbiting the Earth. This comes from pieces of abandoned rockets and out-of-service satellites, but it is mainly the result of the collision between these different elements, because a chain reaction and tends to damage other functioning satellites. In the Starlink fleet, 3% of the workforce had already fallen by 2020. This therefore adds more debris and threatens the thousands of other satellites in low orbit.
Like many other modern satellites, Starlink’s machines still have the ability to leave Earth’s orbit to propel themselves into the great vacuum of space. According to SpaceX, the failed satellites will gradually fall back to Earth and disintegrate in the atmosphere. But with the growing craze for satellite megaconstellations, the space debris problem will only intensify.
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