Flying a solar powered aircraft at night is clearly not an easy task, but one of the teams working on this intriguing technology now claims to have done it twice on the trot. A report on the BBC, followed up by a company press release, says that Zephyr, a solar powered unmanned aerial vehicle (UAV) has successfully stayed aloft under power for 54 hours while flying out of the White Sands test range in New Mexico. Zephyr, which was developed by the rather absurdly named UK defence contractor QinetiQ, has a wingspan of 18 metres and weighs 30 kilos; it reached an altitude of 17,787 metres during the flight, which was mostly carrried out on autopilot, and carried an unspecified “surveillance payload”.

Apparently a solar powered aircraft developed by AC Propulsion stayed up for 48 hours a couple of years ago, but its remote control pilots turned off its motors now and then to conserve power. Zephyr’s lithium sulphur batteries kept it going all night long. Still, the flight apparently will not officially set a new world endurance record, because it was not invigilated by the FAI.

The BBC piece has a lot of context on other teams working with similar technology, not to mention a video of three members of the team launching the UAV by hand. There’s no word as to whether the flight was conceived of as a tribute to the late great Paul MacCready (Economist obituary), a pioneer of solar powered as well as human powered flight. But it probably should have been.

PS: want to build your own photo-reconnaissance UAV? You can! (But not a solar powered one. Yet.)

Image credit: Qinetiq