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For many in the audience, the most unlikely scene in the 2013 sci-fi film, “Gravity,” saw a space shuttle torn apart by hyperspeed space debris from a destroyed satellite. Some viewers found the event unlikely. Why was the debris there? Why was it going so fast? Why didn’t the shuttle see the debris in time?
Unfortunately, the scene was based on real science. As of the end of 2023, nearly 3,000 defunct satellites are orbiting Earth (per the European Space Agency) at speeds measured in the tens of thousands of kilometers per hour. They compete for space with around 4,700 operational satellites as well as objects like rocket boosters, space shuttles, and the ISS. Additionally objects in low Earth orbit (LEO) eventually re-enter the atmosphere and can threaten people on the ground due to uncontrolled descents. In contrast, geostationary orbit (GEO) objects typically do not re-enter the atmosphere and remain in space, posing long-term debris risks but not immediate threats to people on Earth.
NASA has even named and warned of the Kessler Effect, a cascading effect that could see low earth orbit so crowded with space debris that launching new satellites and crews could become prohibitively difficult for generations.
How can this be prevented? One answer is to change how things are launched. Another answer is to stop crashing satellites into each other.
Preventing future collisions with better tech: GuardianSat
“Our vision at GuardianSat is to create a safe and sustainable space environment that enables the growth of the orbital infrastructure and continued exploration of space,” said Chris Rohe, co-founder of GuardianSat. “If satellites continue to fly blind, the resulting cascade of debris will shut down space for generations.”
While the focus is often on low Earth orbit (LEO), geostationary orbit (GEO) also faces significant challenges. GEO, about 35,786 kilometers above the equator, hosts vital communication, weather, and surveillance satellites crucial for broadcasting, forecasting, and defense. Satellites in GEO offer continuous coverage, reducing the need for large LEO constellations like Starlink. One GEO satellite can cover one-third of the Earth’s surface, minimizing congestion and collision risks in LEO. However, GEO is challenging to monitor and the nearby graveyard orbit is densely populated with defunct satellites and debris pose significant collision risks. These debris clouds can persist for centuries, exacerbating the Kessler Effect, potentially disrupting global networks and weather predictions.The company aims to provide a combination of software and hardware that can be installed on GEO satellites to protect them from orbital threats. This means satellites can not only see trouble coming but do something about it. These “active space-based threat sensing and self-protection solutions” are a pivotal part of the GuardianSat mission to enhance “space domain awareness.” Which is all to say, stop things from running into one another.
Thousands upon thousands of potential disasters
It also means actively keeping an eye out for unaccountable accidents. The ESA currently tracks around 35,510 pieces of space debris in orbit, any one of which could bring down a satellite. Tracking that many objects from Earth is difficult, and it’s impossible to warn each satellite of every possible collision; warning a single space shuttle of an incoming threat is a feat in itself!
Giving satellites their own “microwave/lidar detection and intelligent processors to detect and track approaching objects,” feels like a much more realistic solution. The company’s combination of “passive and active defenses” can even include what they call “kinetic interceptors” to knock incoming debris aside.
Predicting future threats
GuardianSat also points out that satellites, civilian or otherwise, have become an essential part of “civil, strategic, and military infrastructures globally,” and imagine scenarios in which satellites must defend themselves against deliberate attacks. Such a future could certainly be possible, as the idea of shooting down a satellite isn’t exactly new, although the invention of co-orbital weapons may be troubling for some.
Whether or not GuardianSat is ready for a near-earth space opera, it’s the kind of future thinking that it’s going to take to keep satellites operational and keep low earth orbit open for business. With so much space debris in orbit and new satellites launching all the time, earth’s skies are a crowded place that can’t afford the kinds of collisions that, to many, seem to be only a matter of time.
