Scientists at the University of Wales Aberystwyth have developed a prototype flying robot they hope will pave the way for a new type of Mars probe.

The Aberystwyth Lighter Than Air Intelligent Robot (Altair) consists of a helium-filled balloon and a gondola containing electric motors, a microprocessor and navigation system.

The prototype 'Aerobot' is already working in the laboratory and the team are designing a more sophisticated five-metre long version.

Altair is designed to work with the minimum of intervention and provide a platform for cameras and atmospheric sensors.

An autonomous probe flying through the skies of the Red Planet could gather a huge amount of data about its surface and weather patterns.

Scientists in the United States have already studied the possibility of using gliders or balloons in the thin Martian atmosphere.

The Aberystwyth team hope to attract interest from the European Space Agency for their proposal.

Europe pays Mars a visit

The Esa is in the final planning stages for its first mission to Mars - Mars Express - which is scheduled to be launched in 2003.

The probe will use an orbiting module and a small, British-designed lander called Beagle 2.

It is too late for Altair to be included in the mission - but the ESA may follow up Mars Express with further probes, and a robot balloon may be an attractive approach.

Phil Summers, who is working on Altair for his PhD thesis, believes the team may not have to wait for long.

"There are Mars missions every couple of years, depending on the planetary alignments.

"We are aiming for 2005."

Altair 1 carries a microprocessor with 64k of memory for the control software, a battery, servos and electric motors for the two propellers that steer the craft.

The gondola also contains infrared and ultrasonic navigation systems that enable the robot to manoeuvre around special beacons and control its altitude.

Altair is designed to fly itself within parameters set by the researchers.

Signal delays

A robot probe on a planet as distant as Mars could be out of contact with Earth for hours and would need to use a form of artificial intelligence to make its own decisions.

The project leader, Dr Dave Barnes, believes this aspect is fundamental.

"There is a huge delay on radio signals - it can be up to 20 minutes one way - so you cannot remotely control a device like this from Earth.

"You can offer it some form of high level instructions, such as a latitude and longitude, but it has to have some form of onboard intelligence to fly itself and sort out problems."

Altair 1 has cost thousands of pounds to design, test and build - but a finished 'Aerobot' probe capable of withstanding the rigours of the Red Planet could cost more than £25m.