The United Kingdom's Ministry of Defence has announced its intention to exercise an option for the manufacture and operation of a third Airbus Zephyr S High Altitude Pseudo-Satellite (HAPS) unit.

Flying at some 65,000ft, the ultra-lightweight Zephyr S is uniquely capable of providing persistent surveillance or communications over the same area of land or sea for weeks at a time without landing. The precise purposes for which the UK MoD will use its Zephyrs have not been disclosed.

The Zephyr S will be delivered ready for flight trials in summer 2017.

"Zephyr is a highly cost-effective complement to satellites and conventional aircraft with the potential to bring unique communication and surveillance capabilities to the UK and other nations," said Sophie Thomas, HAPS Programme Manager.

Running exclusively on solar power and flying above the weather and civil air traffic, the latest generation Zephyr S has a wingspan of 25 meters, is 30% lighter and can carry 50% more batteries than its predecessor. This enables the Zephyr S to carry heavier payloads for its surveillance and communications roles. The Zephyr S HAPS is designed to fly continuously for over a month if required before landing, being refurbished, and flying again.

As well as for military purposes, Zephyrs can be used for humanitarian missions, precision farming, environmental and security monitoring, and to provide internet coverage to regions of poor or zero connectivity.