Space debris

Space debris‏‎, also known as space junk or orbital debris, refers to defunct man-made objects in space—particularly in Earth's orbit—that no longer serve a useful function. These include derelict spacecraft, abandoned launch vehicle stages, mission-related debris, and fragmentation debris.

Origin

Space debris is a byproduct of the approximately 5,000 satellite launches since 1957. Many of these satellites have fallen into disuse, been damaged, or are obsolete, thus becoming space debris. The first notable case of space debris was the Vanguard 1 satellite, which was launched by the United States in 1958 and remains in orbit as of today.

Types of Space Debris

Space debris can be categorized into three main types: operational debris, non-operational debris, and natural debris.

Operational debris includes active satellites and any equipment or particles that are intentionally released during normal operations.

Non-operational debris includes defunct satellites, spent rocket stages, and fragments from the disintegration, erosion, and collisions of larger items.

Natural debris includes meteoroids and other celestial bodies that exist in space but can pose a threat to both manned and unmanned spacecraft.

Risks and Dangers

Space debris poses a significant risk to both manned and unmanned spacecraft. The high velocity of space debris can cause severe damage to functional spacecraft and satellites. This risk is further amplified by the Kessler Syndrome, a scenario in which the density of objects in low Earth orbit is high enough that collisions between objects could cause a cascade, each collision generating space debris that increases the likelihood of further collisions.

Mitigation and Removal

Several methods have been proposed to mitigate and remove space debris, including de-orbiting, re-orbiting, and physical removal. De-orbiting involves lowering the orbit of the debris so that atmospheric drag will cause it to re-enter and burn up in the Earth's atmosphere. Re-orbiting involves moving the debris to a less congested orbit. Physical removal involves capturing and removing the debris, either by bringing it back to Earth or moving it to a disposal orbit.

See Also

• Satellite collision
• Space surveillance
• Space traffic management