Just 10 years ago, there may have been only a thousand or so active satellites orbiting our planet, but in ten years there will be tens or even hundreds of thousands. Experts have been sounding the alarm for years that Earth’s orbit is getting too crowded. So how many satellites can we launch into space before it becomes too much?

The first signs that the situation is getting very tense are already there. McDowell’s British colleague, Hugh Lewis, is another often-heard cautious voice that discredits entrepreneurs in the new gold rush in space. Lewis, an astronaut professor at the University of Southampton in England, has been posting regular updates on his Twitter page for several years detailing the increase in so-called merger events of two objects in space – functioning satellites or fragments. space junk – It is dangerous to approach each other.

Let’s take SpaceX’s Starlink as an example. According to the information provided by Elon Musk’s company US Federal Communications Commission (FCC)(opens in new tab) Last December, SpaceX’s autonomous collision avoidance system performed 26,037 orbital maneuvers with Starlink satellites over a two-year period, from December 1, 2020, to November 30, 2022.

“By around 2027 or 2028, the Starlink cluster could have performed one million collision avoidance maneuvers over its lifetime. It also potentially corresponds to the earliest time they have performed 350 collision avoidance maneuvers on a satellite. [на п’ять років життя]. We’re talking about potentially hundreds or even thousands of maneuvers every day.”

In short, in less than five years, Starlink satellites could run out of fuel in less than their intended lifetime due to the large number of avoidance maneuvers they will have to perform.

So how many more satellites can be safely placed in Earth orbit? The answer to this question is not clear. Lewis says certain orbital altitudes are more vulnerable than others. For example, the Starlink satellites orbit at an altitude of 342 miles (550 kilometers) above sea level. by land. Objects at this height usually don’t stay in space very long after they stop working. Even if at the end of their mission their engines fail and they are unable to turn the ship back. earth atmosphere In order to burn out instantly (as most operators promise), the orbits of these satellites naturally deteriorate within a few years due to atmospheric drag. However, this natural cleaning ability of Earth’s orbit decreases with altitude.

“The space environment is like a system that you get in and out of,” Lewis said. “We launch objects into space, and the flow that normally occurs through atmospheric drift is the only mechanism we have to naturally remove objects from the environment. However, over 1,000 kilometers [600 миль] atmosphere doesn’t really do anything because it’s so rare. no sink; The numbers can only grow.”

The OneWeb constellation lives in this nefarious altitude range, as does the smaller Globalstar.

Most mega-constellation operators are committed to providing enough fuel for their ships at the end of the mission to land where the Earth’s atmosphere can take care of everything. But the possibility of technical failure still worries experts. In 2012, the European Space Agency, an outspoken campaigner for sustainable space operations, failed to launch the 8.8-tonne (8-metric-ton) Envisat Earth observation satellite. with It orbits 480 miles (772 km) above Earth. The ship, which will continue to orbit the planet for centuries, is now one of the most dangerous pieces of space debris.

McDowell says humanity will likely explore the natural possibilities of near-Earth space “the hard way.” Despite the promises of mega-constellation operators, the astrophysicist doubts that everything will remain manageable in the coming years.

“Five to ten years from now, we’ll have 20,000 to 100,000 satellites, and I very much doubt the peak number of 100,000 will be able to operate safely,” McDowell said. Said.