What is Space Debris?

Galactic Garbage: What Actually is Space Debris?

The void that envelopes our planet and the entire solar system is not spared of debris. Space debris, also called orbital debris or space junk, refers to objects along the Earth's elliptical path and orbit. Most of these objects are created by humans, and serve no useful purpose.
Space debris comprises spent rocket stages, defunct satellites, fragments of explosions, paint flakes, dust and slag, coolant remnants, and other particles. These objects or the resultant clouds are capable of triggering destructive collisions that could cause erosive damage and malfunctioning of satellites. This phenomenon is studied as the Kessler Syndrome. Today, an international awareness towards this has generated the use of special spacecraft, designed to clean up the 'mess'.

Understanding the Phenomenon
Space debris refers to the 'blanket of junk' orbiting Earth. It comprises jettisoned parts of spacecraft, nuts and bolts, solar cells, abandoned satellites, cores of nuclear reactors, and solid fuel fragments. All these orbit the Earth at a velocity of 25,000 miles per hour, vertically rising to altitudes that measure thousands of miles. With the help of radar and optical monitoring, NASA endeavors cleaning up this man-created spacial garbage.

The Types
NASA has identified the following components of junk orbiting the planet, among a host of others:
  • Remnants of the 1958 satellite, Vanguard I.
  • A glove lost on the first American spacewalk mission, by astronaut Ed White.
  • Cameras lost by Soviet Mir cosmonauts and Sunita Williams of STS-116.
  • A wrench, toothbrush, pair of pliers and tool bag.
Hazard Analysis
The spacial 'environment' is threatened by the debris most concentrated in the lower orbit, extending into the geosynchronous layers. Hazard analysis uncovers the risk of catastrophic impact due to the spread of debris over longer orbital periods and higher apogees. NASA uses optical detectors, such as lasers, for tracking them. However, the ability to track components as small as 1 cm makes the 'clean-up' mission very difficult.

This hazard is studied with the help of Gabbard diagrams that highlight perigee and apogee altitudes, plotted against orbital periods of each studied fragment. A 'space-junk' catalog record of over 600,000 objects is maintained by NASA. Research involves the readings on measurement generated by the ESA Space Debris Telescope, TIRA, the Goldstone and Haystack radar and Cobra Dane. The data is converted into validate debris models, to assess impact risk and ensure regular tracking.

Collector Vehicles
There are over a million bits of debris orbiting our planet, and its components are breaking up. The Center for Orbital and Reentry Debris Studies (CORDS), California, studies and analyzes spacial debris, establishing junk-free zones and generating ground for collision avoidance. The flying flotsam is capable of delaying launches and creating collision zones in space. The 'graveyard of scraps' is growing, but is being monitored by NASA's Orbital Debris Program. The cosmic clutter is currently tracked by the U.S. Space Surveillance Network. Trash-collector vehicles are being designed to drag the components into the lower orbit, before disposing the components into 'safe' earth zones. The United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) has generated voluntary guidelines to prevent collisions between satellites, due to this spatial phenomenon.

The Inter-Agency Space Debris Coordination (IADC) Committee is an international forum dedicated to global coordination of activities related to the clean-up program. The organization is committed to the exchange of vital information on the phenomenon, research activities between member agencies, facilitation of opportunities in research, and the progress of designed cooperative activities. The main aim of the IADC is to identify debris mitigation possibilities. The member agencies include:
  • NASA: National Aeronautics and Space Administration
  • BNSC: British National Space Center
  • ESA: European Space Agency
  • DLR: German Aerospace Center
  • ROSCOSMOS: Russian Federal Space Agency
  • JAXA: Japan Aerospace Exploration Agency.
  • CNSA: China National Space Administration
  • ISRO: Indian Space Research Organization
  • NSAU: National Space Agency of Ukraine