Space Debris Sources
In addition to satellites that are no longer used, there are a variety of events and mechanisms that lead to the creation of space debris. Sources of Space Debris include:
Mission-related objects (MRO) released during space missions, such as explosive bolts and covers. Also entire rocket upper stages and dual launch devices that enter orbit with satellites or space probes and remain there.
An unusual case is the upper rocket stage of the Surveyor 2 space probe mission: It temporarily returned to Earth orbit in 2020 and made headlines because it was initially thought to be a "captured" main-belt asteroid.
of satellites or upper stages - these are caused by deliberate blasts, by the ignition of residual propellants from upper stages, and by the vaporisation of cryogenic propellant components in upper stages where residual propellants remain. The expansion of these propellants during vaporisation can cause the upper stages to explode. Explosions can also be triggered by discharges in batteries of the satellites. It is believed that about 200 explosions have occurred in orbit since the beginning of spaceflight.
Satellites used during the Cold War - probably still today - specifically to neutralise the enemy's spy satellites. Most of them self-destruct to cause an intentional collision with the target, sometimes accompanied by an explosion. Neither their number nor their victims are publicly known, as both they and their targets are under the strictest military secrecy.
Anti-Satellite Missiles (ASAT).
The use of these weapons can hurl the debris produced by the destruction of satellites (such as Fengyun-1C) into a very wide range of orbits - including those that reach high altitudes.
These are not scrapes in failed docking manoeuvres, but accidental collisions at high relative velocities, in GEO usually 100 to 1000 m/s, but possibly also 1.5 km/s (satellite against Hohmann transfer stage), in LEO typically 10 km/s, which disintegrates both missiles. Examples include the separation of the Cerise satellite's stabilisation mast (extendable mast) by an older Ariane rocket upper stage and the spectacular satellite collision on 10 February 2009, which resulted in over 2,000 pieces of cataloged debris and a rough estimate of half a million particles over 1 mm.
In 1978, NASA consultant Donald J. Kessler predicted the scenario known as the Kessler Syndrome, according to which impacts of small fragments and meteoroids would each produce many larger fragments, causing the debris problem to grow at an accelerated rate even if no more satellites were launched.
The ESA Space Debris Telescope frequently found bright objects whose rapid descent in the high atmosphere indicates a very high surface-to-mass ratio, up to 30 mÂ²/kg. They could be thermal debris from satellites.
West Ford Dipoles
In the early 1960s, a diffuse sphere of many millions of fine wires (18 mm Ã— 0.018 mm) was intended to form a reflector for radio communications. Separation on release was only partially successful; flakes formed, a manageable number of which still vagabond at altitudes above 2500 km.
produce micrometre-sized aluminium oxide particles during the burn-up. At the end of the burn-up, larger slag objects can also emerge, whose diameter can reach several centimetres.
from space-based Buk nuclear reactors from Soviet spy satellites of the series known in the West as RORSAT. In 16 of these satellites, the reactor core was jettisoned after the mission was completed, releasing the coolant from the primary cooling circuit NaK-78 (approx. 8 kg each). The NaK was distributed in drops of various sizes on the orbits of the RORSAT satellites. However, due to various orbital disturbances and the rotation of the nodal line, the NaK is increasingly spreading to other orbits as well.
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