Scanning the skies for debris hazards

ESA's SSA programme: watching for hazards from space
A purpose-built radar system will scan low Earth orbit for dangerous debris objects
6 June 2011

Today, orbiting satellites are threatened by some 700,000 pieces of debris. Assessing related risks requires surveillance, tracking and statistical observations with radars and telescopes. ESA is designing a system to catalogue debris and warn satellite operators when to take evasive action.

This week, over 150 global experts will meet at an ESA-organised conference to share the latest research findings on space debris, surveillance technology, orbital hazard detection and satellite safety. The first European Space Surveillance Conference (ESS2011) will be held 7–9 June in Madrid, Spain.

The conference spotlights ESA's Space Situational Awareness (SSA) programme, now in the preliminary phase, which aims to put in place a 'three-legged' system to warn of hazards posed by orbital debris, space weather and natural objects like asteroids that may strike Earth.

Extensive reuse of existing resources

Conferences like ESS2011, involving a large number of experts, are crucial for knowing the best way forward.

Since 2009, the Agency's SSA team have been working to define the system's overall technical structure, while actively evaluating existing European assets, such as scientific research radars and telescopes, which could contribute to SSA.

The development strategy is based on an extensive use of national and European assets, as well as the procurement of the missing components of the future SSA System.

2011 is a busy year for SSA surveillance development activities, perhaps the most urgent leg of the programme.

Complex engineering and scientific challenge

A new generation of software was recently implemented to warn when satellites could be hit by orbiting debris.

"At the moment, it is undergoing extensive testing using known debris orbits, but it's a first step toward the software we'll use when Europe has its own surveillance capability," says ESA's Emmet Fletcher, Head of the Space Surveillance and Tracking Segment at the SSA programme office.

Hosting an international conference like ESS2011 is crucial for staying up to date with global best practises and meeting scientific experts who work with current-generation radars and telescopes.

Debris surveillance is a complex engineering and scientific challenge in part due to the fact that even a tiny piece of debris - just 1 centimetre across - can seriously damage or even destroy a functioning satellite if it impacts at orbital velocities.

ESA's SSA programme: watching for hazards from space
EISCAT facilities Sweden

"We are now finalising a pan-European survey and test of existing tracking facilities, such as radars and telescopes located in France, Germany, Italy, Norway, UK, Switzerland and Spain," says Emmet.

"Knowing how precise these are is fundamental to designing ESA's new SSA system, which may make use of their data in combination with debris readings obtained by new, highly accurate radars and telescopes in the future.

"We know there is a huge amount of knowledge across Europe and globally. Having a single forum where experts from around the world can meet and present new information is vital and helps move our collective know-how forward.

"New techniques, new approaches and sharing past experience helps all space-faring nations work more safely in orbit."

Conference brings together global experts

At the conference, over 150 experts from more than 20 nations will take in over 50 presentations. There are also dedicated information sessions on policy, optical and radar observations, and engineering design as well as presentations from the future customers of the SSA system.

Today, Europe cannot scan as much of space as necessary to provide comprehensive debris warning services to private and public spacecraft operators, like those flying telecommunication, climate and weather satellites.

"But we have to ensure that the design for the next-generation debris surveillance and tracking systems that SSA will propose at the end of the current preliminary phase in 2012 will perform as needed at a cost that is realistic," says Emmet.

"This is a challenging task, and achieving it means that conferences like ESS2011, involving a large number of experts, are crucial for knowing the best way forward."

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