The unmanned, solar-powered aircraft, known as Zephyrs made by Airbus, fly above the jet streams and will stay aloft for months on end.
Designed and built in Britain, the vehicles will carry small payloads that might consist of reconnaissance cameras or communications equipment. In test flights above 65,000ft, high-definition video with a ground resolution of 50cm has been downlinked in real-time.
The MoD is likely to buy two Zephyrs in the first instance.
In 2010, a Zephyr-7 flew uninterrupted for 14 days in an MoD demonstration in the US. Very efficient solar cells combined with energy-dense lithium-sulphur batteries kept its propellers continually turning, maintaining an altitude well above any disruptive weather.
Airbus is hoping the vote of confidence from the British MoD will lead to more sales, not just in the military sector but in the civil sphere as well – in environmental monitoring, for example.