BBC News Online: Sci/Tech

Beam-riding rocket lifts off

They say that unlike today's space shuttles which are powered by engines and fuel, the new rocket could ride into space on a laser beam.

A prototype has already reached 90ft in tests. Scientists say a more powerful laser should get the rocket up thousands of feet higher.

It is hoped that the laser rocket engine will be used to launch a satellite into space within the next five years.

The BBC's Science Correspondent, James Wilkinson, says a mirror helps launch the beam-riding craft.

The vehicle is placed above a curved mirror, and when the laser is fired, the mirror focuses the beam under the rim.

This then heats the air to around 30,000 degrees, causing the air to explode which in turn pushes the vehicle up.

Professor Leik Myrabo, an engineer involved in the project, said: "With beam-riding craft we can just tilt the transmitter and it will follow So you can tip it and tilt in into a trajectory that you want to boost into space."

Scientists say their main problem is that the rockets are burning up because they get so hot during their flight.

However, they say they are confident they will eventually find a material which can withstand the heat.

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