Misconception of high concentration of space debris in near Earth orbit

Satellites are the mainstay by which we communicate digitally to friends in different parts of the world. However, with more frequent rocket launches for propelling satellites into orbit as well as the decommissioning of old satellites, there is attendant increase in space debris orbiting the low earth orbit region where many weather satellites orbit, as well as the geostationary orbit space (360000 km away from Earth) where many communication satellites sit.


But, does the common picture depicted in people’s minds of a large mass of space debris orbiting the Earth at various orbital heights square with the real scenario? The answer is no. Considering that even a small piece of space debris could cause catastrophic failure of a multi-million dollar spacecraft, presence of a large “cloud” of almost impenetrable space debris around Earth would make launching of satellites into orbit almost impossible. Additionally, even if the spacecraft could be launched to its designated orbit, a cloud of space debris could pose significant threat to the spacecraft and systems during its service life, since impact with even small space debris fragments could cause catastrophic damage to the spacecraft.


Hence, given that there is substantial space debris in orbit coupled with increasing number of commercial, civilian space programs and military satellite launches with attendant release of space debris upon launch, how does the space environment around various orbits of Earth cleanse itself of debris that could impact on launch success of spacecraft and uninterrupted operation of satellites?


The key concept to remember is that space debris of whatever size and mass would eventually de-orbit and be burned up in the Earth’s atmosphere. Specifically, without thrust, gravity pull from Earth would gradually reduce the forward momentum of space debris; thereby, preventing them from remaining in orbit indefinitely. Therefore, space environment around Earth, especially in low Earth orbit, is self-cleansing. Specifically, space debris would eventually lose forward momentum and be pulled gradually towards the Earth’s atmosphere and be burned up upon re-entry.


Overall, in understanding an idea, it is important to work through the fundamental science and engineering concepts that underpins a phenomenon, such as whether there is an impenetrable cloud of space debris around Earth. To this question: the nature in which anything, without thrust, would lose momentum and forward inertia, meant that gravity would eventually pull the debris into the upper reaches of the atmosphere, where they would be destroyed by combustion. Hence, there is substantial amount of space debris around Earth due to recent satellite launches, but given the de-orbiting effect of debris that is without forward thrust, the space environment around Earth remains relatively clear of obstacles that could prevent the successful launch of satellites.


Category: space science,

Tags: space debris, de-orbiting, forward momentum, gravitational pull, re-entry,




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