by
Margarita Chrysaki*
But what is ‘space debris’ and where did it come from? How we got it spinning around our planet? Does it affect the human life and if yes what are the measures taken to avoid it?
According to the European Space Agency (ESA) space debris is defined ‘as all the inactive, manmade objects, including fragments, that are orbiting Earth or reentering the atmosphere.’ These inactive artificial objects are parts of retired satellites e.g. the upper stages of launch vehicles or discarded bits left over from separation.
Travelling up to 17,500 miles per hour these uncontrolled ’29,000 objects larger than 10 cm, 750,000 from 1 to 10 cm, and more than 166 million from 1 mm to 1 cm’ as ESA underlines, can collide with other objects. The fragments being generated from the collision will bring a new collision creating a chain reaction, known, also, as the Kessler Syndrome. In other words, even if all manned activities in Space stop the very next day, the amount of debris would continue increasing due to collisions between them.
During the 7th European Conference on space debris organized by ESA on 18-21 April in Darmstadt, Germany, Holger Krag, the Head of Unit of ESA Space debris Office gave his insight into this self-sustaining cascading collision of Space debris in a low Earth Orbit: ‘It is not compared with a gunshot. The energy contained in a 1cm particle hitting a satellite of that velocity roughly corresponds to exploding grenadine’.
A recent example of debris hitting a satellite took place on 23rd August 2016. ESA engineers noticed that the electricity production of the Copernicus Sentinel-1A satellite was slightly decreasing and there were slight changes in its orientation and orbit. Following an investigation, it occurred that a small particle of a millimeter size hit with high speed the solar wing and caused a damage measuring a diameter of roughly 40 cm. In 2015, ESA’s Integral and Cluster-1 satellites performed two large orbit-change manoeuvres to reenter Earth’s atmosphere safely during the next decade. However space debris not only put at risk satellites infrastructures, but has also been a threat for the crew taking part in space missions. It is worth mentioning that the International Space Station performs avoidance space debris manoeuvres every year.
Back on Earth, there are two ways someone could see the effects of space debris, though rarely happens by now. In the past there were few cases where parts of retired satellites destroyed human property and even posed a danger for the human life. For example, on 24 September 2011, the German satellite ROSAT while reentering Earth’s atmosphere, was unlikely to burn up entirely.
Thankfully, no human loss occurred as the surviving space hardware splashed down in a remote area of the Pacific Ocean. Today, we depend on data related to the weather forecast, telecommunications and other important applications provided by the satellites. Therefore, satellites have become an indispensable part of our daily routine and any damages caused by these uncontrolled junk could disrupt most parts of the abovementioned services.
With regards to the actions taken to the problem of space debris in Europe, the Space Situational Awareness (SSA) programme is on board since 2009 with three segments Space Weather (SWE), Near Earth Objects (NEO) and Space Surveillance and Tracking (SST) and aims to gain awareness on the situation in Space by tracking all the objects that constitute a potential threat. Through Space surveillance, it is possible to detect, catalogue and predict these objects on time and place with great accuracy. Using sensors, such as telescopes or radars, provide a powerful tool for the characterisation of the orbital debris environment and its route changes.
In addition to this, a set of space debris mitigation and remediation actions is one of the priorities in the EU Space policy agenda. ESA is investigating ways to eliminate or remove large inactive particles from the most populated orbits and are the source of generating new debris. New technologies are being developed in sending up vehicles to remove debris using capturing techniques that ranges from giant nets to robotic hands.
Mechanisms that identify the attitude motion of an object will, also, help to avoid collisions for operational payloads. In parallel, all these new technological projects constitute undoubtedly an ideal driver for a new spacecraft system and hardware design that will reduce the threat of active debris. This would create a new sustainable generation of satellites ensuring that there will be no impact on the environment in Space.
Though guidelines to protect the near Earth space do exist, most of the time they are not applied. Guidelines such as changing and re-qualified some of the satellite’s components that will not produce any debris at the end of its mission are rarely applied due to the high cost for the preparation of these technologies. Europe should actively interact with all international players of the Space sector and take an active part in the discussions particularly regarding the implementation of such guidelines. Indeed, space debris is an issue that should concern all nations, especially the spacefaring ones that need to cooperate, develop and apply a set of concrete and mostly updated guidelines for an active control of the Space debris environment.
*Margarita Chrysaki is a Brussels-based Political analyst. She has a BSc and a Master in Political Sciences with special focus on Corporate Social Responsibility. Currently, she is making a profound research in the field of space activities and EU strategy on Space.
** The article is dedicated to Anastasia Kalpogiannaki
By: N. Peter Kramer
