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This scenario of increasing space debris will play out even if we don’t put anything else in orbit.
This scenario of increasing space debris will play out even if we don’t put anything else in orbit.
D. J. Kessler, 2011
D. J. Kessler, 2011
The launch of Sputnik 1 satellite in 1957 opened a new chapter in human history, known popularly as the Space Age. Only 63 years later, nearly 100 States and organisations own satellites and this number continues to grow, with the result of an increasingly “congested, contested and competitive” Earth orbit environment, where there are currently about 3,000 * functional satellites, accompanied by a deadly cloud of an estimated over 128 million pieces of debris (trash of human origin – from bits of rockets and expired satellites, to broken up equipment including flecks of paint and smaller particles).
Why deadly? Because the velocity in orbit is ten times faster than that of a bullet, about 27,000 km/h ** (in the Low Earth Orbit (LEO) - up to 2000 km above the Earth's surface). To put it in perspective, the impact energy of a marble travelling at such speed equals to an explosion of a hand-grenade.
In increasingly packed orbits, accidental collisions between satellites have already occurred adding thousands more debris to the mix and above 500 km altitude, the lifetime (how long it takes to fall back to Earth) of debris stretches from decades to thousands of years, with the most congested orbits above this mark.
As is true for many environmental problems,
As is true for many environmental problems,
the control of the orbital debris environment may initially be expensive,
the control of the orbital debris environment may initially be expensive,
but failure to control leads to disaster in the long-term.
but failure to control leads to disaster in the long-term.
D. J. Kessler, 2009
D. J. Kessler, 2009
Countries that own satellites. (Image Credit: Union of Concerned Scientists)
TV, flights, navigation, farming and healthcare
TV, flights, navigation, farming and healthcare
international peace and security
international peace and security
disaster management and response
disaster management and response
communication – e.g. internet and phones
communication – e.g. internet and phones
finance – e.g. bank transactions
finance – e.g. bank transactions
scientific research – e.g. astronomy,
scientific research – e.g. astronomy,
climate and environmental monitoring
climate and environmental monitoring
In 1978, a NASA space debris expert, Donald J. Kessler, predicted that past a certain critical point, as the number of objects in orbit intensifies, the total amount of space debris will keep on increasing exponentially due to a chain reaction in collisions. Inducing this phenomenon, now known as the “Kessler Syndrome”, brings up very serious concerns, as debris generated from collisions significantly increases the probability of further collisions, which could eventually render some orbits useless for future generations.
Keeping the LEO environment clean is of particular importance. Even satellites that are not located in orbits with high collision risk (those above LEO) will have to be replaced after decommission and the replacement satellite will have to traverse LEO to get to its intended location. But as the number of debris grows the likelihood of collisions rises, making this feat increasingly difficult.
In 2013 the UN Group of Governmental Experts warned that "threats to vital space capabilities may increase ... as a result of both natural and man-made hazards and the possible development of disruptive and destructive counterspace capabilities". LEO is one of the primary locations for military satellite deployment. Should conflicts arise they will be the chief target and the use of destructive anti-satellite weapons will be nothing short of catastrophic. On the other hand, incapacitating satellites via non-fragmenting means could also add to the debris problem.
Such aggressive activities could set up a situation where a single satellite failure could lead to
Such aggressive activities could set up a situation where a single satellite failure could lead to
cascading failures of many satellites in a period of time much shorter than years.
cascading failures of many satellites in a period of time much shorter than years.
D. J. Kessler, 2009
D. J. Kessler, 2009
Humanity cannot adequately deal with its waste on Earth, let alone in space. To keep space sustainable and our satellites safe debris removal and evasion are ALREADY a necessity and this is neither cheap or easy ***, nor is it free from human error, as evidenced by the satellite impacts which have already occurred. Given the unpredictability of the times we live in and the fast paced developments in space, it is unfortunately not too reassuring that the FIRST mission with the aim to remove a single piece of debris from orbit is planned for launch in 2025.
(Top) Window of the International Space Station - 7 mm-diameter circular chip gouged out by the impact from a tiny piece of space debris, possibly a paint flake or small metal fragment no bigger than a few thousandths of a millimetre across. (Image Credit: ESA)
(Right) "Every year hundreds of millions of dollars are spent to maneuver spacecraft to avoid collisions."
(Image Credit: Lokheed Martin)
"Can we clean up space before it's too late?" (Video Credit: Asher Isbrucker).
* With the advent of large satellite constellations (thousands of satellites working in unison), such as SpaceX, OneWeb, Telesat, Boeing and others, these numbers are about experience a drastic spike in the near future.
** The orbital speed decreases with distance from Earth.
*** In fact one of the problems associated with space debris removal technology is that it's dual-use (could be used as a weapon). Without proper international agreements and cooperation debris removal itself poses additional challenges.
Click here to find out why current space laws are not adequate to address weaponisation of space.
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