Space Surveillance



The systematic monitoring of the environment in space is necessary to ensure the safe exploration and use of space. The safety aspect takes on even greater importance as scientific and commercial applications and services based on space infrastructures become more prevalent. The European Space Agency faced the challenge in 2008 when it launched its Space Situational Awareness (SSA) programme, which seeks to ensure the safe access and use of space. The SSA programme involves the identification of potential dangers that space poses to infrastructures (both on the ground and in flight) and to the population.

A "halo" of space debris surrounds the Earth
A "halo" of space debris surrounds the Earth

The sheer scope of space activities has led to a proliferation of objects orbiting the Earth. It is estimated that operational satellites account for only 6% of the objects identified. The vast majority of objects are fragments of the upper stages of rockets, debris from collisions, explosions, etc. of unknown origin. Certain fragments are so small that they are difficult, if not impossible, to detect. The first accident between two operational satellites occurred on 10 February 2009 at an altitude of 776 km above Siberia. A private American communications satellite hit a Russian military satellite at a relative speed of 11.7 km/second.

The monitoring of space weather is another important aspect of space surveillance. In addition to producing fascinating polar aurora in the ionosphere, magnetic storms can damage the highly sensitive electronic instruments and solar panels on satellites. Ionospheric currents also pose a danger to ground infrastructures, particularly for high-voltage networks and electrical substations. Magnetic storms disrupt modern navigation and communication systems and can even render them inoperable.

Swiss companies and research institutes take part in the SSA programme. They contribute know-how for the development of technology, software and hardware. They also apply their astronomical research expertise to observe near-Earth objects (debris in space) as well as satellites and to study space weather.

Further information