European researchers de-congesting space
European researchers have developed a new space surveillance system to keep abreast of the increasing quantities of space debris floating around the orbital highway. This debris poses serious threats to all the satellites and other spacecraft that risk being damaged or even destroyed if they come into contact with it. As part of the European Space Agency's (ESA) Space Situational Awareness (SSA) programme, researchers from the Fraunhofer-Gesellschaft in Germany are playing a key role in this project by supplying the receiver for part of the radar system. The Fraunhofer Institute for High Frequency Physics and Radar Techniques FHR in Wachtberg will develop the demonstrator in collaboration with Spanish company Indra Espacio, which will develop the transmitter array. Orbital space can be described as a congested motorway with an endless stream of satellites constantly orbiting Earth. Much like on a 'real' road, this flow is frequently punctuated with congestions. Yet in space, you are more likely to come across a stray asteroid or comet than a traffic jam. The region is also strewn with debris from human space activities such as burnt out rocket stages and fragments of disintegrated spacecraft, some space watchers would even go so far as to say that all of these random objects constitute a veritable floating junkyard. There are currently an estimated 20,000 objects with a minimum diameter of 10 centimetres circling Earth, including 15,000 in the low Earth orbit at an altitude of between 200 and 2,000 kilometres. And these objects are by no means snail-paced; reaching speeds of up to 28,000 km per hour, meaning even the smallest particles measuring a centimetre or less in diameter can cause serious damage to or even destroy any unlucky satellite in its path. For example, in February 2009, a retired satellite collided with one of the Iridium communication satellites. As a result of incidents like this, the International Space Station (ISS) has to perform four to five evasive manoeuvres every year. It was in this context that the ESA decided to tackle the problem head on by launching its SSA programme, which began in 2009 and runs until the end of 2011. Using an electronically steerable, inertia-free antenna that can be positioned very quickly, the surveillance system can observe a large number of objects simultaneously, detecting their position to a high degree of accuracy and sensitivity. As there will be between 15,000 to 20,000 objects on the radar for at least 10 seconds every day, this will certainly come in handy. 'Our receiver system, that uses a phased-array antenna as the sensor, is capable of capturing radar signals reflected by satellites and space debris in up to eight directions at the same time,' says FHR department head Dr Andreas Brenner. In its final version, the surveillance radar will be able to detect objects in geostationary orbit at an altitude of approximately 36,000 km above the surface of the Earth, but its power will be mainly concentrated on the low Earth orbit at an altitude of between 200 and 2,000 km, where it will be capable of detecting particles of debris measuring down to a few centimetres in diameter. The data this system collects is likely to be of interest to numerous users, including not only European government departments and space agencies but also satellite operators, insurance companies, energy suppliers and telecommunications companies.For more information, please visit:Fraunhofer-Gesellschaft:http://www.fraunhofer.de/en/
Countries
Germany, Spain