Unmanned aircraft being developed in Christchurch

An artist's impression of the Kea Atmos. Photo / Supplied

A 32-metre wide unmanned aircraft is being built by a Christchurch company – which says it is the largest aircraft of its type ever built in the Southern Hemisphere.

Kea Aerospace said the aircraft would be powered by hundreds of solar cells and three electric motors, which would collect enough energy from the sun each day to enable it to fly for months.

Chief executive Mark Rocket said the "Kea Atmos" would fly at 65,000ft (20km) in the stratosphere, an altitude twice as high as commercial passenger jets.

The aircraft would be used to capture data for businesses and organisations across the world.

Rocket said it was currently prohibitively expensive to get regularly updated, high-resolution data that covered large areas.

An artist's impression of the Kea Atmos. Photo / Supplied

He said the Kea Atmos would fly 20 times closer to the Earth than satellites and enable its camera to acquire a much high image quality, without the expense of operating in space.

There was currently a "large data intelligence gap" that could not be met by satellites, manned aircraft or drones, he said.

"Only a small percentage of New Zealand's land and waterways are aerially surveyed each year."

The company would be building and flight-testing "multiple prototypes" in 2021, build the first full-scale Kea Atmos in 2022, and launch the aerial imaging service in NZ and Australia in 2023.