Breakdown: What is space junk and why is it a problem?
MEMPHIS, Tenn. (WMC) - As long as humans have been exploring space, we’ve also been creating a bit of a mess.
Since the dawn of the space age in the 1950s, we have launched thousands of rockets and sent even more satellites into orbit.
Orbiting our planet are thousands of dead satellites, along with bits of debris from all the rockets we’ve launched over the years, creating an ever-increasing risk of collision as we launch more.
While there are about 2,000 active satellites orbiting Earth at the moment, there are also 3,000 dead ones littering space.
According to NASA, more than 27,000 pieces of orbital debris, or “space junk,” are tracked by the Department of Defense’s global Space Surveillance Network (SSN) sensors.
What is space junk?
Space junk, or space debris, is any piece of machinery or debris left by humans in space.
It can refer to big objects such as dead satellites that have failed or been left in orbit at the end of their mission, or smaller things, like bits of debris or paint flecks that have fallen off a rocket.
Earlier this year, a five-millimeter hole was discovered in a robotic arm of the International Space Station. It was thought to have been caused by something no larger than a fleck of paint traveling through space ten times faster than the speed of a bullet.
So if a fleck of paint can do this kind of damage, imagine what happens when the larger mashups occur.
In 2009, an inoperative Russian spacecraft slammed into a U.S.-based communications satellite, spewing a whopping 1,800 pieces of debris and many other shards too small to count.
For satellites to collide is rare, however, SpaceX’s Starlink satellites alone are involved in about 1,600 close encounters between two spacecraft every week, according to Hugh Lewis, the head of the Astronautics Research Group at the University of Southampton, U.K.
Several countries including the USA, China and India have used missiles to practice blowing up their own satellites in order to avoid collisions. This, of course, still results in thousands of new pieces of dangerous debris.
How does space junk get into space?
All space junk is the result of us launching objects from Earth, and it remains in orbit until it re-enters the atmosphere.
Some objects in lower orbits (Low Earth Orbit (LEO)) often re-enter the atmosphere after a few years -- many of which don’t reach the ground as they burn up while re-entering Earth’s atmosphere.
But debris or satellites left at higher altitudes - where communications and weather satellites are often placed in geostationary orbits - can continue to circle Earth for hundreds or even thousands of years.
Space junk in numbers
- 2,000 active satellites in Earth’s orbit
- 3,000 dead satellites in Earth’s orbit
- 34,000 pieces of space junk larger than 10 centimeters
- 128 million pieces of space junk larger than 1 millimeter
What risks does space junk pose to space exploration?
NASA says due to the rate of speed and volume of debris in LEO, current and future space-based services, explorations, and operations pose a safety risk to people and property in space and on Earth.
In total, across all satellites, hundreds of collision avoidance maneuvers are performed every year, including by the International Space Station (ISS), where astronauts live.
The International Space Station has conducted 29 debris avoidance maneuvers since 1999, including three in 2020, according to NASA.
“Such maneuvers with the space station require about 5 hours to plan and execute using the station’s Russian thrusters, or the propulsion systems on one of the docked spacecraft.”
How can we clean up space junk?
Space junk is no one countries’ responsibility, but the responsibility of every spacefaring country. The problem of managing space debris is both an international challenge and an opportunity to preserve the space environment for future space exploration missions, according to NASA.
“Finding ways to remove at least some of all that space junk should be a top global priority,” says Donald Kessler, a retired NASA senior scientist for orbital debris research. In the late 1970s he foretold the possibility of a scenario that has been dubbed the Kessler syndrome: Collisions creating more debris, thus resulting in a runaway chain reaction of collisions and more debris. It is also known as collisional cascading.
Kessler proposed it would take 30 to 40 years for such a threshold to be reached and today, some experts think we are already at critical mass in Low Earth Orbit (LEO), says NASA.
The United Nations ask that all companies remove their satellites from orbit within 25 years after the end of their mission. This is tricky to enforce, though, because satellites can (and often do) fail. To tackle this problem, several companies around the world have come up with novel solutions.
These include removing dead satellites from orbit and dragging them back into the atmosphere, where they will burn up. Ways we could do this include catching it in a huge net, using a harpoon to grab a satellite, using magnets to grab it, or even firing lasers to heat up the satellite, increasing its atmospheric drag so that it falls out of orbit.
A private orbital debris removal company called Astroscale has created a magnetic capture system dubbed End-of-Life Services by Astroscale-demonstration (ELSA-d).
Since launching ELSA-d into space on March 22, 2021 this past March, Astroscale has been conducting end-of-life on-orbit servicing demonstrations that were scheduled over a six-month period and licensed by the UK Space Agency and has successfully captured its first debris August 25, 2021.
“This has been a fantastic first step in validating all the key technologies for rendezvous and proximity operations and capture in space,” says Nobu Okada, Founder & CEO of Astroscale. “We are proud to have proven our magnetic capture capabilities and excited to drive on-orbit servicing forward with ELSA-d.”
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