Satellites to probe asteroid threat to Earth

A fleet of mini-probes could be sent to rendezvous with asteroids under an ambitious British-led plan to investigate the threat of space objects hitting the Earth, it was revealed today.

The five “micro-satellites” – only 60 centimetres long and weighing 120 kilograms – would each target an asteroid of a type considered to be potentially dangerous.

Each asteroid would be physically different and measure between 400 metres and 1,300 metres in diameter.

A consortium led by QinetiQ, formerly the major part of the British government’s Defence Evaluation and Research Agency (Dera), has submitted the proposal to the European Space Agency.

One attraction of the plan is its low cost, by space mission standards - expected to be no more than £100m (€149m).

The key objective would be to understand more about the threat posed by more than 100,000 Near Earth Objects (NEOs) hurtling around the Solar System.

Throughout the Earth’s 4.5 billion-year history asteroids and comets have collided with the planet on numerous occasions, and there have been many near misses.

A giant object which slammed into the Earth off the coast of Mexico 65 million years ago is widely believed to have wiped out the dinosaurs.

In 1908, a relatively small object flattened 2,000 square kilometres of Siberian forest at Tunguska, and a near-miss was reported as recently as June last year.

The asteroid mission has been named Simone (Smallsat Intercept Missions to Objects Near Earth).

Dr Roger Walker, Simone senior mission and systems engineer at QinetiQ, said: “There is a critical science need to learn more about NEOs. They are made from a variety of materials, such as metal, rock, carbon porous matter or rubble.

“The objective of the Simone mission will be to determine the characteristics of different NEO targets so we can plan how best to respond to the impact threat.”

A key element of the mission would be the hi-tech electric propulsion system used to power the spacecraft, said Dr Walker.

Once in space, the probes would be driven by ion propulsion engines developed by QinetiQ.

These provide thrust by shooting out a stream of electrically charged particles.

Although the output power is low, it can be sustained over a long period, allowing the spacecraft gradually to build up speed.

Power for the ion engines will be generated by two ultra-lightweight solar arrays.

QinetiQ hopes to see the same combination of micro-satellite and ion propulsion technology used to send probes on deep-space missions to Mars, Venus, and the main asteroid belt.

Each Simone spacecraft will have instruments designed to examine the physical and chemical make-up of its target asteroid.

It is hoped the missions will help scientists predict the risk posed by asteroids and develop effective strategies for dealing with different types of object.

Scientists from the Open University and the technology company SciSys (UK) are also involved in the project, together with two Italian-based companies.