For his Starlink project, Elon Musk intends to send 12,000 satellites into orbit by 2025. Ultimately, the firm SpaceX hopes to receive authorization to send up to 48,000. The goal is to provide a high-speed, low-latency satellite Internet connection anywhere in the world at a rock-bottom price.
The number of satellites is still standard, when we know that the total number of satellites ever put into orbit by humans amounted to 9,000 until then. In addition, other states and businesses want to enter the race for high-speed satellite Internet connectivity in a constellation, which adds tens of thousands of satellites to the count.
Mega-constellations, made up of hundreds or thousands of devices, are viewed with a negative eye by part of the scientific community and in particular by astronomers. This is because the initial coating on Starlink satellites tended to reflect sunlight. To the naked eye, it looked like a single, faster star, but the situation was quite different when it came to observing the sky. Indeed, Starlink’s satellites were initially extremely bright and left trails of light on telescope images, obscuring other stars.
To address the problem, SpaceX has coated its satellites with a dark, non-reflective paint called DarkSat. This made it possible to halve the luminosity of the satellites, but it is not yet enough to observe the sky properly. Satellites in low orbit and deployed by the thousands all the same tend to return more and more regularly in the field of view of telescopes, as their number increases. Even with DarkSat, they still reflect too much of the Sun. This can be particularly disastrous for the study of near-Earth asteroids, as they are even more visible at sunrise and sunset, a good time to practice.
SpaceX does not budge and tries to find solutions to the problem to establish a compromise with the astronomers. To go further, the Starlink satellites have been fitted with a VisorSat. These are kinds of deployable visors acting as sun visors.
A report from the first SATCON 1 constellation satellite conference gives ten recommendations to companies wishing to deploy their devices. Apart from darkening the equipment, it is recommended to orbit less than 600km high to minimize night-time reflections, to control the orientation of the craft, to find solutions to avoid light trails in the astronomical observation and to make satellite coordinates available in real time to scientists.
Risk of collision
Another problem that is often raised is the risk associated with the amount of objects present at similar altitudes. This in fact increases the risk of collision between different satellites, which would lead to an unwelcome chain situation. To avoid collisions, Starlink’s satellites are equipped with artificial intelligence thrusters and reflexes.
However, it has happened on several occasions that satellites from different constellations failed to collide. On March 30, competitor 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. Even if the chances of them colliding were only estimated at 1.3%, the event would undoubtedly have caused a dramatic chain reaction. Starlink had to manually deactivate the AI of its satellite for the two objects to move away from each other.
A problem of coordination therefore now arises between the various players in low-orbit space. In addition, the increasing number of satellites that occupy the low orbit can pose a problem when launching objects into space, since it will be necessary to pass through various layers of thousands of small satellites located at altitudes. different.
There are believed to be hundreds of thousands of debris orbiting Earth. This comes from pieces of abandoned rockets and out-of-service satellites (in the Starlink fleet, 3% of the workforce was already broken down in 2020), but it is above all the result of a collision between these different elements.
Like many other modern satellites, Starlink’s machines still have the ability to lift off Earth’s orbit to propel themselves into the great space vacuum. According to SpaceX, the failed satellites will gradually fall back to Earth and disintegrate in the atmosphere. But with the growing craze for mega-constellations of satellites, the problem of space debris will only intensify.