Space Debris

Space Debris, also known as Space Junk or Space Pollution, is man-made debris found in space, outside the earth's atmosphere. These objects in orbit around the Earth have no use value and pose a threat to space travel. It can range from paint flakes or metal particles, to no longer needed satellite instrument lids, bolts or springs, to a complete discarded artificial moon or rocket stage.

Space Debris or space junk is the residue of human activity in space, left in Earth's orbit since the beginning of space travel in the late 1950s. The very first man-made space debris thus comes from the protective casing of the Soviet satellite Sputnik and the coupling device of its launch vehicle. Space debris consists mainly of space engineering waste, spent rocket stages, old satellites, debris and fragments from crashes and explosions, but also dropped screws, nuts and paint chips.

The growing amount of space debris has led to a growing awareness of the problem. In recent years, energy has been devoted to both avoiding and trying to clear space of debris. The subject has also been the subject of several films and TV series.

Until December 2016, five satellite collisions have generated space debris. At least 700,000 pieces of space debris are orbiting the Earth at a speed of 28,000 kilometres per hour to which must be added the very smallest fragments. Scientists estimate (2013) more than 170 million particles smaller than 1 centimetre, 670,000 that are 1-10 centimetres and 29,000 that are larger than 10 centimetres each posing a threat to objects in orbit around Earth. In the event of a collision, space debris can damage existing satellites and space stations. It can also harm astronauts on spacewalks and impede their work in space.

Space debris also poses a risk to contemporary and future launches. At the moment, it is necessary to keep a close eye - as far as possible - on where new satellites are launched, in order to minimise the risk of collision. However, it is not always possible to prevent existing space debris from continuing to generate new debris, for example through collisions. This phenomenon is sometimes referred to as the Kessler syndrome.

Space Debris Orbit

Especially those pieces that keep circling the earth in orbit can be a problem, depending on the orbit.

There are also pieces with a heliocentric orbit, such as several copies of the third stage of the Saturn V rocket, and the second stage of the Falcon Heavy rocket (with car attached). These pose less of a problem.

Space stages often come down in a defined area shortly after launch, but in some cases they also come down uncontrolled after dozens of revolutions around the Earth, where of the location only can be predicted to be somewhere more or less below the expected orbit, see Safety Measures Downing Central Stage Missed or Failed.

Space Debris Orbits around the Earth.
Space Debris Impact in the solar cell wing of the SMM satellite. The hole is 0.5 mm in diameter, the impactor much less.

Space Debris Distribution

The number of particles varies with altitude. Below 400 km, they burn up within a few years. In the orbits of 600 km to 1500 km (sun-synchronous orbit) and 36,000 km (geostationary orbit) preferred by satellites, they accumulate.

The particle flux (number of particles passing an area of one square metre per year) varies with size. Over several orders of magnitude, the measured distribution (red curve in the diagram) follows a power law with exponent 4 (blue straight line). These particles are meteoroids of natural origin. The deviation for particles smaller than 0.1 mm is caused by the solar wind. Above 10 mm, space debris dominates.

The amount of space junk around Earth has hit a critical point.

Space Debris Quantities

Until spring 2010, about 4700 rocket launches with a good 6100 satellites took place in 50 years of space travel. Of these, 15,000 fractions of rockets and satellites remained, up to complete upper stages. According to the USA catalogue, that is 15,000 objects of at least ten centimetres in size, and presumably another 7,000 secret objects. If the minimum size is reduced to one centimetre, 600,000 objects are estimated, to which about one million smaller particles must be added. This results in a total mass of space debris of about 6300 tonnes, of which 73% of the objects are in Low Earth Orbit (LEO), but of the total mass this is only 40%, or about 2700 tonnes. Particularly affected is the altitude of 800 kilometres, the preferred flight path of reconnaissance satellites. The ISS flies between 350 and 400 kilometres; so far it has had to avoid objects larger than one centimetre several times. In geostationary orbit (GEO) at an altitude of 36,000 kilometres around the Earth, only 8% of the fragments are located, but this is where the large telecommunications satellites weighing several tonnes orbit, with an estimated total weight of 33%, or about 2,000 tonnes. The remaining 19% of the objects with 27% of the mass are in other orbits.

Famous pieces of Space Debris

The oldest piece of space debris is the Vanguard 1 launched on March 17, 1958. The satellite stopped functioning after six years and is still in orbit.

In the past, tools have been lost during spacewalks, which are now also floating around in space. These include a glove that astronaut Ed White lost on the first U.S. spacewalk. Michael Collins lost a camera on the spacecraft Gemini 10. In addition, garbage bags, a screwdriver and a toothbrush have been lost. In November 2008, Heidemarie Stefanyshyn-Piper lost a bag of tools during mission STS-126.

China destroyed an old weather satellite with a ballistic missile in January 2007. In 2019, India also conducted such an intercept. The Russians and Americans have not done such a thing since the 1980s. In February 2009, two satellites collided. In March 2021, a remnant of a Russian Zenit rocket stage launched in 1996 collided with a Chinese satellite, which was lost. Such events led to a huge increase in the amount of space debris.

Space Debris in Popular Culture

The theme of space debris has appeared in the Japanese manga series Planetes, created by Makoto Yukimura in 1999-2004; it was also adapted into a high-profile anime in 2003-04. The story is set in the future and revolves around four people working to collect space debris in the orbits of the Earth and the Moon.

In the science fiction film Gravity, Russia has detonated an anti-satellite weapon, resulting in a large amount of space debris in low Earth orbit. The debris smashes the fictional space shuttle Explorer, and eventually it's up to lead character Dr. Ryan Stone (played by Sandra Bullock) to make his own way back to Earth.

Space debris has also found a place in the world of computer games, with the strategy game Habitat, which involves building, flying and fighting battles with space stations built from space debris.


  • Donald Kessler (Kessler 1991), "Collisional Cascading: The Limits of Population Growth in Low Earth Orbit", Advances in Space Research, Volume 11 Number 12 (December 1991), pp. 63–66.
  • Donald Kessler (Kessler 1971), "Estimate of Particle Densities and Collision Danger for Spacecraft Moving Through the Asteroid Belt", Physical Studies of Minor Planets, NASA SP-267, 1971, pp. 595–605. Bibcode 1971NASSP.267..595K.
  • Donald Kessler (Kessler 2009),, 8 March 2009.
  • Donald Kessler (Kessler 1981), "Sources of Orbital Debris and the Projected Environment for Future Spacecraft", Journal of Spacecraft, Volume 16 Number 4 (July–August 1981), pp. 357–60.
  • Donald Kessler and Burton Cour-Palais (Kessler 1978), "Collision Frequency of Artificial Satellites: The Creation of a Debris Belt" Journal of Geophysical Research, Volume 81, Number A6 (1 June 1978), pp. 2637–46.
  • Donald Kessler and Phillip Anz-Meador, "Critical Number of Spacecraft in Low Earth Orbit: Using Fragmentation Data to Evaluate the Stability of the Orbital Debris Environment", Presented and the Third European Conference on Space Debris, March 2001.
  • (Technical), "Orbital Debris: A Technical Assessment" National Academy of Sciences, 1995. ISBN 0-309-05125-8.
  • Jim Schefter, "The Growing Peril of Space Debris" Popular Science, July 1982, pp. 48–51.

Further reading

  • "What is Orbital Debris?", Center for Orbital and Reentry Debris Studies, Aerospace Corporation
  • Committee for the Assessment of NASA's Orbital Debris Programs (2011). Limiting Future Collision Risk to Spacecraft: An Assessment of NASA's Meteoroid and Orbital Debris Programs. Washington, D.C.: National Research Council. ISBN 978-0-309-21974-7.
  • Klotz, Irene (1 September 2011). "Space junk reaching 'tipping point,' report warns". Reuters. Retrieved 2 September 2011. News item summarizing the above report
  • Steven A. Hildreth and Allison Arnold. Threats to U.S. National Security Interests in Space: Orbital Debris Mitigation and Removal. Washington, D.C.: Congressional Research Service, 8 January 2014.
  • David Leonard, "The Clutter Above", Bulletin of the Atomic Scientists, July/August 2005.
  • Patrick McDaniel, "A Methodology for Estimating the Uncertainty in the Predicted Annual Risk to Orbiting Spacecraft from Current or Predicted Space Debris Population". National Defense University, 1997.
  • "Interagency Report on Orbital Debris, 1995", National Science and Technology Council, November 1995.
  • Nickolay Smirnov, Space Debris: Hazard Evaluation and Mitigation. Boca Raton, FL: CRC Press, 2002, ISBN 0-415-27907-0.
  • Richard Talcott, "How We Junked Up Outer Space", Astronomy, Volume 36, Issue 6 (June 2008), pp. 40–43.
  • "Technical report on space debris, 1999", United Nations, 2006. ISBN 92-1-100813-1.
  • Robin Biesbroek (2015). Active Debris Removal in Space: How to Clean the Earth's Environment from Space Debris. CreateSpace. ISBN 978-1-5085-2918-7.
  • Khatchadourian, Raffi, "The Trash Nebula: Millions of man-made artifacts are circling Earth. Will one of them cause a disaster?", 28 September 2020, pp. 44–52, 54–55. "By one estimate, there are a hundred million bits of debris that are a millimetre in size, a hundred million as small as a micron. We live in a corona of trash. [T]he problem, if ignored, could destroy all the satellites that orbit near the Earth – a loss that would be more acutely felt as humanity increasingly relied on space." (p. 47.)


Visit our media section for a complete overview.


International Space Station
Orbital Debris
Space Debris
Space Debris Mitigation
Space Junk
Space Pollution
Space Trash
Space War
Space Waste


DeepDove: Space Network (2021-09-21). Space Debris | Home. Retrieved , from




This page was last changed on 2021-09-21.