Half of all active satellites are now from SpaceX. Here’s why this can be a problem

SpaceX’s rapidly growing fleet of Starlink internet satellites now make up half of all active satellites on Earth.

On February 27, the aerospace company launched 21 new satellites to join its Starlink internet fleet for broadband internet. That brought the total number of active Starlink satellites to 3,660, or about 50 percent of the roughly 7,300 active satellites in orbit, according to an analysis by astronaut Jonathan McDowell using data from SpaceX and the US Space Force.

“These high-internet low-orbit constellations have come nowhere since 2013, to reach the orbit of 2023,” said McDowell, of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. “It’s really a huge change and a huge industrial low orbit.”

SpaceX’s Starlink satellites will be launched from 2019 with the goal of sending internet to remote parts of the globe. And for so long, astronomers have warned that bright satellites could mess up our view of the cosmos by leaving streaks in telescope images as they slide past.SN: 3/12/20).

Even the Hubble Space Telescope, which orbits more than 500 kilometers above the Earth’s surface, is vulnerable to these satellite streaks, as are other satellite constellations. From 2002 to 2021, the percentage of Hubble images affected by light from orbit will increase by about 50 percent, astronomer Sandor Kruk of the Max-Planck Institute for Extraterrestrial Physics in Garching, Germany, and colleagues reported on March 2. Nature Astronomy.

The number of images partially intercepted by satellites is still small, the machine found, rising from about 3 percent of images between 2002 and 2005 to more than 4 percent between 2018 and 2021 for one of the Hubble cameras. But there are already thousands more Starlink satellites now than there were in 2021.

“Fraction” [Hubble] “The images transmitted by satellites are now small with little impact on science,” Kruk and colleagues write. “However, the number of satellites and space debris will only increase in the future.” The team predicts that by the 2030s, the probability of a satellite passing through Hubble’s field of view any time it takes an image will be between 20 and 50 percent.

The sudden jump in Starlink satellites also poses a problem for space traffic, says astronomer Samantha Lawler of Queen’s University in Canada. Starlink satellites all orbit at a similar distance from Earth, just over 500 kilometers.

“Starlink is the densest space ever,” said Law. Satellites constantly navigate out of each other’s way to avoid collisions (SN: 2/12/09). And it’s a popular high-orbital — Hubble is there, and so is the International Space Station and the Chinese space station.

“If there is any collision” [between Starlinks]any type of mishap could immediately affect human life,” said Lexler.

SpaceX launches Starlink satellites roughly once a week – it will launch 51 more on March 3. And the company isn’t the only one launching internet satellites. By the 2030s, there could be 100,000 satellites crowding low Earth orbit.

So far, there are no international regulations to limit the number of satellites launched by private companies or to limit which orbits they can occupy.

“The speed of commercial development is much faster than the speed of rule change,” McDowell says. “There is a need to overhaul the traffic management space and the space organization can usually cope with large traffic projects.”