A couple of weeks ago, Federal Communications Commission Chairwoman Jessica Rosenworcel proposed new rules that would require satellite operators in low-Earth orbit (LEO) to dispose of their satellites within five years of completing their missions.
Rosenworcel is passionate about not cluttering up the Earth’s sky with space junk. Speaking at the Global Aerospace Summit earlier this week, she said, “Right now there are thousands of metric tons of orbital debris in the air above. Since 1957, humanity has put 10,000 satellites into the sky. More than half of those satellites are now defunct.”
The space junk raises the risk of collisions with active satellites, and it makes it harder to launch new objects into higher orbits. Not to mention the fact that it’s just kind of gross to surround our planet with orbiting garbage.
The issue is also taking on new urgency of late with companies such as SpaceX having already deployed more than 2,000 satellites for its Starlink fixed wireless access (FWA) service and most recently announcing work with T-Mobile to deploy a whole new constellation of satellites for mobile phone communications.
But how do satellite companies dispose of their orbiting equipment once it becomes obsolete? It’s not clear whether all satellite companies have technology to safely do this. But SpaceX says it has developed methods for “controlled deorbit to low altitudes” once a satellite has reached its end of life.
According to a SpaceX webpage that the company directed Fierce Wireless to, SpaceX coordinates with the 18th Space Control Squadron to “initiate a high drag mode, causing the satellite’s velocity to reduce sufficiently” that it deorbits. That process takes roughly four weeks.
“SpaceX is the only commercial operator to have developed expertise in flying in a controlled way in this low altitude, high drag environment, which is incredibly difficult and required a significant investment in specialized satellite engineering,” it says.
Explaining the nitty-gritty details, SpaceX says, “When a satellite’s altitude decays, it encounters a constantly increasing atmospheric density. Initially, these molecules impact the satellite, but as the air density increases, a high-pressure shock wave forms in front of the spacecraft. As the satellite slows down and descends into the atmosphere, its orbital energy is transferred into the air, heating it to a plasma. The hot plasma sheath envelops the satellite, causing intense heating. Starlink satellites are designed to demise as they reenter the Earth’s atmosphere, meaning they pose no risk to people or property on the ground.”
The company says it has already safely deorbited over 200 satellites using this approach.