UK-made solar aircraft hopes to steer global race to conquer the stratosphere

For most of our satellite needs, we rely on Elon Musk's SpaceX but could we have a solution closer to home ITV News Science Editor Martin Stew

We rely on satellites for everything from weather forecasting, to communications and even spying. What if we could engineer a cheaper, reusable alternative closer to home?

Inside a hanger in Hampshire, BAE Systems is trying to develop just that.

A solar-powered plane designed to fly twice as high as commercial planes. It has a wingspan of 35 metres (the same as a Boeing 737) but weighs just 150 kilograms - about as much as a motorbike.

Power-to-weight ratio is essential, as PHASA 35 will aim to stay in the stratosphere for six months at a time, fueled only by the Sun.

It can carry a similar payload to low orbit satellites but has the advantage of being able to stay anchored over a certain point.

Ideal, developers say, for military missions - but also monitoring the planet and weather below.

There is a global race to conquer the stratosphere. It’s only in recent years that solar panels and batteries have become advanced enough to make the idea a reality.

Inside the hanger, engineers are working to save every gram and make sure the plane can cope with the rigours of life at 66,000 feet.

“The stratosphere is more similar to Mars than what you see on Earth,” engineer Darcy Nortcliffe explains to me.

She’s using a thermal vacuum chamber to recreate conditions, which she says “allows [them] to replicate -93 degrees and the low pressure you’d experience on Mars.”

The biggest challenge, it turns out, is getting the fragile craft into the stratosphere in the first place. PHASA 35 has a top speed of 20mph.

The ascent to altitude can take 10 hours. Meteorologists play a key part in finding a weather-free window to allow the craft to make it to 66,000 feet intact.

Flight testing is being carried out in the arid deserts of America. Engineers hope the craft will be ready to be used commercially by 2027.

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