27-metre wingspan, 138 kilos: DLR video shows how the HAP-alpha solar aircraft was built
The uncrewed solar aircraft HAP-alpha is meant to fly at around 20 kilometres one day. A new DLR video follows it from construction to its first flight in Cochstedt.
Photo: NASA Armstrong Flight Research Center / NASA/Tony Landis / Wikimedia Commons, Public domain (cropped and resized)
Video: YouTube · DLR · youtube.com
The German Aerospace Center (DLR) released a video on 15 October about its high-altitude platform HAP-alpha. It shows how the uncrewed, solar-electric aircraft was developed and built from scratch at DLR and follows it up to its first flight on 2 September 2026 at the National Experimental Test Center for Unmanned Aircraft Systems in Cochstedt, Saxony-Anhalt. According to DLR, 16 institutes and facilities are involved, led by the DLR Institute of Flight Systems.
HAP-alpha has a 27-metre wingspan but weighs only 138 kilograms. The platform is designed to fly at up to about 20 kilometres in the lower stratosphere – at around 30 km/h near the ground and about 50 km/h at high altitude. There it is to test Earth observation and communication technology under real conditions, such as the high-resolution camera system MACS-HAP and the radar HAPSAR. On its first flight it stayed airborne for about 70 minutes and climbed to 180 metres; the wind was not allowed to exceed 1 metre per second.
The biggest challenge in the first flight of such a high-altitude aircraft is its vulnerability, said Andreas Bierig, acting head of the DLR Institute of Flight Systems. Next, the team will evaluate the flight data and prepare a second low-altitude flight. Only after the test campaign are flights at greater altitude over sparsely populated areas such as the sea to follow.