Space Waste 101: Everything You Need to Know
Quick Key Facts
- There have been more than 570 events where spacecraft fragmented in Earth’s orbit after an explosion or collision.
- Space waste has increased by 50% in the past 5 years.
- Detectable space debris weighs over 8,000 metric tons.
- There are more than 23,000 objects larger than a softball in Earth’s orbit.
- Protecting satellites from collisions with space junk makes up about 5% to 10% or more of total mission costs, which are well in the millions per satellite.
What is Space Waste?
Space waste is a problem that goes by many names, including space junk, space pollution and space debris. While space debris technically refers to natural meteoroids as well as human-caused pollution, orbital debris is a term specifically used for human-created waste that now orbits the Earth.
Space waste has many causes, including abandoned technologies sent into space or fragments of spacecrafts. The issue is becoming a growing problem as space travel increases. Even the tiniest pieces of space junk can damage spacecraft on a mission, and the more we pollute space, the risk of collisions increases.
Types of Space Pollution
Just like the pollution in the oceans or on land, there are different types and sizes. In space, all space debris, big or small, can be detrimental if it collides with a spacecraft, especially since these objects travel approximately 15,700 mph in low Earth orbit. Most orbital debris, which is caused by humans, comes from two main sources: payloads and rockets.
Space Debris vs. Orbital Debris
The overarching term is space debris, which encompasses both natural and human-made waste found in space. Orbital debris is specific to human-created waste that has fallen into Earth’s orbit.
Orbital Debris Types
There are a couple of common types of orbital debris that come from either payloads (space objects with specific functions, like satellites) or rockets.
According to the European Space Agency, payloads refer to space objects that, aside from launch functionality, are designed to serve a specific purpose in space. Payload-related waste primarily relates to satellites.
- Payload mission-related objects (PM): Mission-related objects include tools, cables, equipment covers and other objects released on purpose during a mission.
- Payload fragmentation debris (PF): Fragmented debris refers to fragments or unintentionally released components lost during a specific, traceable event, like a collision.
- Payload debris (PD): This term refers to fragments of a payload that are unintentionally released and cannot be traced to a specific event.
Another common type of orbital debris comes from rocket bodies, or space objects with launch functionality. Rockets release three common types of debris:
- Rocket mission-related objects (RM): Similar to PM, RM refers to rocket mission-related objects, like engines or shrouds, released intentionally during a mission.
- Rocket fragmentation debris (RF): Explosions or collisions can cause rockets to unintentionally fragment or release parts of the rocket body into space.
- Rocket debris (RD): Rocket debris includes rocket body fragments or pieces that were not released on purpose and also can’t be traced back to a specific event.
Space Waste by Size
Aside from the different types of space pollution, this waste also can be classified into different sizes.
- Micrometer: There are hundreds of millions of micrometer-sized debris in space.
- 1 Millimeter: NASA estimates about 100 million pieces of debris that is at least this size, which is about 0.4 inches. Most space waste smaller than 1 centimeter is undetectable.
- 1 Centimeter: In space, there are about half a million pieces of debris that are at least one centimeter.
- 1 to 10 Centimeters: There are around 900,000 space waste objects of 1 centimeter to 10 centimeters in orbit.
- Over 10 Centimeters: There are about 23,000 pieces of orbital debris that is larger than 10 centimeters, or bigger than a softball. This type of debris includes abandoned technologies, lost tools and defunct satellites.
Causes of Space Waste
Space debris can be natural, such as from meteoroids and their impacts, or human-made. Human-made orbital debris can also be intentional or unintentional. As such, there are several events that can lead to the creation of space waste of all sizes.
Rockets are a top source of space waste and have both intentional and unintentional debris that is released. After takeoff, rocket staging causes the rocket body to detach stages, propellants and/or strap-ons in order to reduce the amount of weight of the rocket.
Spacecraft explosions create a lot of debris and can happen for many reasons, including leftover fuel or clogged spacecraft components. One study from Purdue University found that three upper rocket stages exploded prematurely in 2018 and 2019 due to 1) a clogged vent that led unused propellant to combust, 2) a probable structural failure and 3) likely a collision with another piece of debris.
A single collision can produce thousands of pieces of debris that will remain in orbit for many years. The first-ever collision of satellites involved an inactive Russian satellite and an active U.S. satellite in 2009. The major collision produced about 2,000 pieces of debris 10 centimeters or larger and thousands of pieces of smaller debris. The debris is expected to remain in orbit for several decades, if not over 100 years.
But even a small collision, like a tiny fleck of paint with a spacecraft, can disrupt missions and cause even more debris. Debris can last decades in Low Earth Orbit, threatening future spacecraft and robotics missions. Debris which is about 1 millimeter in size has the highest risk of ending robotic spacecraft missions in Low Earth Orbit.
Smaller than a grain of sand, a micrometeoroid is a tiny piece of a meteoroid, which itself is a fragment typically from an asteroid. Micrometeoroids can enter the Earth’s atmosphere but tend to burn up before they can impact. In space, micrometeoroids don’t burn up before they make impact, which is why they can be dangerous for spacecraft or astronauts on spacewalks.
Anti-satellite weapons, internet satellites and private space exploration also contribute to space debris.
Countries may use missiles to destroy satellites, which can then fragment into thousands of small pieces. The U.S. and Soviet Union tested anti-satellite weapons in the 1960s and 1970s until the mid-1980s. China used a missile to destroy an old satellite, which was broken down into over 3,500 trackable debris pieces. In 2021, Russia used an anti-satellite weapon on a defunct satellite of its own without warning, leaving astronauts sheltering from the high dangers at the International Space Station.
Private companies, including Amazon and its Project Kuiper, OneWeb Corporation and SpaceX’s Starlink are planning to launch thousands more satellites into space in coming years. The projects, called mega constellations, would boost internet access for billions of people but would also create more orbital debris.
Then, there’s the growing interest in space commercialization and tourism through companies like Elon Musk’s SpaceX, Jeff Bezos’ Blue Origin and Richard Branson’s Virgin Orbit. Aside from sending more satellites for internet service into space, companies are testing for passenger flights into space. All this testing and launching contributes more to the orbital debris.
How Much Space Junk Is Out There?
There are about 23,000 detectable pieces of space junk that are about the size of a softball or larger, but there are hundreds of thousands of smaller items that are harder or impossible to detect. The 23,000 detectable pieces of space junk are estimated to weigh around 8,000 tons.
Most of the items in space are no longer active. There are about 4,500 satellites in orbit, but only about 1,500 of those satellites are dead and left in orbit.
The U.S. is responsible for the highest amount of space junk, followed by Russia and China. Russia has the highest amount of objects in space currently.
Where Does the Waste Go?
Human-created space junk goes into Earth’s orbit and concentrates in two locations: Earth’s equatorial plane and Low Earth Orbit. Both active satellites, such as radio or weather satellites, and dead satellites are in geostationary orbit in the equatorial plane about 30,000 kilometers (18641 miles) above the surface of the planet.
Then, there is, even more, junk in Low Earth Orbit, about an altitude of less than 1,000 to 2,000 kilometers (621 to 1,243 miles) but could be as low as 160 kilometers (99 miles) above Earth’s surface.
Debris in the equatorial plane can remain in orbit for hundreds or even thousands of years. Objects in orbit of 600 kilometers or fewer will fall back to Earth, typically burning up before reaching the surface, within a few to several years. Items orbiting between 800 and 1,000 kilometers take hundreds of years, while anything in orbit at 1,000 kilometers or more is likely to stay in orbit for thousands of years.
Risks of Space Junk
Space junk, especially objects in Low Earth Orbit, are a risk to spacecraft, robotics and astronauts for future missions and can have global economic impacts.
One of the most common risks of space junk is collisions with satellites, which can be damaged or completely destroyed if they collide with even small debris. Many satellites that are relied on for communications and Earth observations are at risk of collision with space junk.
Space debris travels at incredibly high speeds, making impacts incredibly dangerous. Spacecraft must go through Low Earth Orbit to continue farther into space, but crews will need to plan and maneuver around the increasing number of objects in Low Earth Orbit to avoid collisions.
The International Space Station must also maneuver around space waste. After Russia fired an anti-satellite weapon in November 2021 to destroy an old satellite, the satellite created more waste. In October 2022, the International Space Station had to increase its altitude to minimize risk of being hit by a piece of the satellite destroyed a year prior.
The Kessler Syndrome, a scenario proposed by NASA scientist Donald J. Kessler in 1978, refers to a chain of events that continually increase the amount of orbital debris. As impacts increase, whether intentional through anti-satellite tests, or not, such as accidental collisions, the amount of space waste increases. It’s proving true: the European Space Agency found that space debris has increased 50% in just the past five years.
In 2020, the Organisation for Economic Co-operation and Development (OECD) published an initial report on the economic impacts of orbital debris. According to the research, costs to protect satellites in geostationary orbit make up 5% to 10% of total mission costs, which are about $10 million to $400 million to launch just one satellite. Satellites in Low Earth Orbit have much higher costs to protect.
Space Junk Solutions
Nations and private companies are coming up with innovative ways to clean up orbital debris and minimize the amount of debris being generated. Here are some solutions introduced in recent years.
Collaborative International Efforts
The Inter-Agency Space Debris Coordination Committee (IADC) has created debris reduction guidelines, including a 25-year rule, where objects should be removed from orbit after this time limit.
The UN has also created Space Debris Mitigation Guidelines, including limiting debris release during spacecraft’s normal operations, avoiding intentional destruction of orbital debris, and minimizing post-mission unintentional break-ups that can happen from leftover fuel or other energy sources.
Outside of international guidelines, countries are also implementing their own guidelines and regulations to minimize and retrieve space waste. In September 2022, the U.S. Federal Communications Commission (FCC) implemented a 5-year limit for new satellites that will apply to U.S. operators.
Also in the U.S., the Department of Defense catalogs orbital debris for tracking, and NASA has stringent safety guidelines and procedures to minimize collision risks.
ESA’s ClearSpace-1 is a first-of-its-kind orbital debris cleanup mission, which is set to launch in 2025-2026. Its initial mission is to collect a 112-kilogram Vespa upper stage, orbiting at an altitude of about 664 to 801 kilometers.
Experts can design and build spacecraft that can re-enter Earth’s atmosphere safely and efficiently, so it isn’t stuck in orbit for centuries. The European Space Agency is embracing a “Design for Demise” philosophy that allows satellites to more easily break down, return to Earth’s atmosphere, and burn up.
Researchers are also exploring ways to design spacecraft that can pick up debris during its mission, following fuel-efficient routes to collect waste without using up too much energy.
How to Clean Up Pollution in Space
More and more researchers, governments, and companies are looking into ways to clean up space pollution. From nets to magnets to lasers, there are many ways under consideration for space junk removal.
Harpoons and Nets
A RemoveDEBRIS spacecraft from the Surrey Space Centre has been in testing and has even successfully obtained a piece of space junk via a deployed net, which pulled the debris into Earth’s orbit to then burn up in the atmosphere within months.
The RemoveDEBRIS has also used a harpoon designed by Airbus Stevenage to spear space junk for collection. The harpoon has barbs to keep the debris from floating away upon impact, and the harpoon is also attached to RemoveDEBRIS via wire to avoid creating more waste.
Sky Perfect JSAT Corp., based in Tokyo, is planning to deploy a vehicle that will use lasers to shoot debris down to Earth by 2025. The vehicle will release targeted lasers that push even small pieces of space junk down into Earth’s atmosphere, where the waste will burn up.
Astroscale has created a “tow truck” for space that uses magnets to collect debris. The End-of-Life Services by Astroscale (ELSA-d) comprises two stacked satellites, with one satellite featuring a magnetic docking device that can collect large pieces of orbital debris. Then, this satellite can descend with the debris until it reaches Earth’s atmosphere and burns up.
The company’s idea is to include docking plates on commercial satellites in the future, so any satellite can collect waste as it orbits. Then, that waste can be picked up later on.
If you can’t remove all the waste in space, what if you could repurpose it? Thats what Nanoracks hopes to do. The company wants to recycle upper stages into space stations, laboratories, greenhouses, or even habitats. As part of its Outpost program, the company’s Mission Extension Kits will provide power, data handling, communications and more to repurposed upper stages. Nanoracks’ Outposts are set to start flying out in 2024.
There are really two pathways for the future of space debris: either we can start collecting debris with solutions ranging from nets and magnets to lasers, or the Kessler Syndrome will continue and render some orbits unusable. Ultimately, countries will need to work together to implement guidelines and enforce policies that can help clean up existing orbital debris and minimize future debris.
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