Sky-Fi: Data with altitude

If you want to see the future, look to the skies. Michael Hickling reports on a team from York University who aim to get lift-off on a stratospheric dirigible called the X-Station.

A team of scientists at York University have come up with an idea that could change country living and transform the economic prospects of millions in the world's remotest corners – as well as offering them off-duty high-speed internet surfing.

The key is a piece of kit that looks like part of a portable barbecue, or possibly a wok with a lid on. To show it in operation, the scientists from York's electronics department bundled all their gear into a van bound for the Swiss Alps, then transferred it to a carriage in the world's steepest cogwheel railway and hauled it 7,000 feet up Mount Pilatus.

Their destination was a hotel on the mountain top overlooking Lucerne. On the hotel's roof a base station was set up to receive the signals from the electronic wok which was loaded on to a helicopter and flown to 10,000 feet, grazing the side of mountains in the process. The end result of this slightly Heath Robinson arrangement was conclusive proof that their means of delivering long-distance wireless broadband (WiMAX) actually did work.

But how much practical use is a hi-tech system that requires a rattling mountain railway to make it happen? This Swiss trip was for demonstration purposes only, not a commercial offering but a one-off to prove the concept. The wok's successor will be the payload not for a helicopter but for a "high altitude platform" or HAP. There's one slight hitch in this plan, however. There are no HAPs around at

the moment.

But one has been built by a Swiss company – hence the York scientists' trip – which will shortly begin test flights. It's an unmanned helium-filled dirigible 100 metres long called X-Station. It will float into the stratosphere some 15 miles above the earth from where it will transmit digital data at lightning speed to homes and offices. An ingenious control system will ensure that X-Station remains more or less stationary above the same point on the Earth's surface. This digital data delivery to customers requires no expensive underground cabling, no forests of mobile phone masts along the way.

Being so high in the sky means there's a line-of-sight link to every terrestrial receiving point. And since transmission takes place mainly through the air, there's 1,000 times less radiation than with transmissions on the ground which have to be strong enough to pass through solid objects like buildings. When the York scientists attended a first presentation on X-Station in 2006, they admit it all sounded incredibly far-fetched.

At that time they were working on part of a wider European Union-funded scheme called the Capanina project, named after an Italian restaurant where the idea was conceived. Its aim has been to develop HAPs that can beam broadband to areas where it's too difficult and expensive to take cable and will bring a benefit for users of mobile phones, digital TV, video, email and the internet.

"We went to Switzerland because the customer wanted to see it working," says Dr John Thornton, a research fellow at York working on the project. Andy White, whose team designed the radio payload, says "We got some strange looks on the mountain railway because it looks like something out of Doctor Who."

"A high altitude platform has a myriad of uses, varying from security to monitoring disasters and crops by a steerable camera," adds Dr Thornton. "They are cheaper and better than satellites which are 35,000 kilometres away and orbiting and can't be landed for refurbishment."

The Zeppelin plant at Friedrichshaven in Germany is where the X-Station was finally put together. The early phase of construction was in a redundant Lego factory. The material required for the outside envelope is so huge the team in the assembly room doing the cutting and preparation were equipped with roller skates and scooters.

Despite the impression this might give, this isn't Toytown. The cost of X-Station is about 60m. That may sound prodigious, but only until you compare it with the price of just one mobile phone mast which is about 550,000.

Even Switzerland requires 1,000 of these for full mobile phone coverage and it's reckoned that one stratospheric airship could do the job of all of them.

Why not use a satellite? Because they can cost 1.2bn and compared with satellites, balloons or airships are dead easy. No rocket and launch pad is required, they can take off from anywhere and can be brought back to earth fairly simply for upgrading and repair.

X-Station is filled 12,000 cubic meters of helium and at take-off looks disappointingly like a shapeless plastic bag. It only assumes its full shape in the stratosphere where the air pressure is one-twentieth of what it is on the ground. One of the biggest challenges is to get it safely through being buffeted by the jetstream.

The man behind the X-Station is an entrepreneur called Kamal Alavi and his Swiss company StratXX Holding AG. Kamal Alavi, who is working with the York scientists, is originally from Iran. He has a background in avionics but made his fortune from inventing a means of recycling electronic equipment printed-circuit boards by extracting the precious metals. He then licensed the process.

The York University team is led by Tim Tozer, the head of the communications research group. In addition to the York connection, the X-Station has an international complexion. Israelis are making the base station equipment. There's a training centre in Romania with Russian, Portuguese and Irish engineers involved.

Another beauty of X-Station, assuming it works, will be versatility. The payload could be changed at fairly short notice so that in the event of a disaster, it could be brought into play to get people speaking to each other again. After Hurricane Katrina struck New Orleans, the telephone system disintegrated and it was five days before it was working again. Helicopters had to be pressed into service to deliver signals for a basic communications set-up.

The potential is enormous, assuming this new technology proves effective. About 20 X-Stations, or equivalent Haps, would be required to cover Europe. Africa would need twice as many. For this idea not even the sky is the limit.

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