Low earth orbit is becoming increasingly crowded with satellite traffic and, as Gravity showed us, increasingly treacherous. So rather than try to squeeze yet another spacecraft into the mix, a French consortium has begun development on a super-high altitude, autonomous dirigible that will skim along the edge of the stratosphere.
The Stratobus, which is still in its early concept stages, is being developed by a team from Thales Alenia, Airbus, Zodiac Marine, and CEA-Liten. It is designed to perform a variety of roles—from border monitoring and surveillance to communication and navigation signal relaying—at the stratospheric height of 13 miles (20.9 km).
The prototype, which the team expects to be operational within five years, will be 91 metres long and 22 metres wide with a carbon fibre envelope supported by a semi-rigid frame. A pair of thrust vectoring electric fans won't so much provide propulsion as counter the stratosphere's strong winds, keeping the dirigible locked in a fixed position over the Earth. Its rotating solar panel array should generate enough power to hoist payloads of up to 200 kilograms.
And since the StratoBus will operate autonomously, it will be able to stay aloft for up to a year at a time. Its overall service life expectancy, however, is a startlingly brief five years, barely half of the 10-15 year endurance of the average geostationary communications satellite currently in orbit. There's no word yet on how much each will cost to construct, but they should prove significantly less expensive to operate given the astronomical cost of ruggedising, testing, and launching traditional geostationary satellites—even with their abbreviated life spans. [Thales via Wired]