Air-to-air refuelling/automatic catch basket

Unmanned research aircraft with coupling unit

Prometheus is a research and experimental vehicle that has already been used for five years to develop forward-looking functions for unmanned and automated flying. The focus is on manoeuvres and missions that require highly dynamic responses to unknown or highly variable environmental conditions, such as collision avoidance or automated low-level flight over unexplored terrain.

The latter category also includes the in-air coupling of two unmanned flying vehicles using an active catch basket. In this case, the receiver aircraft – the Prometheus – automatically flies in close formation with the aircraft in front. A connection then has to be established with the catch basket dragged by the Prometheus, while the relative position to the front aircraft has to be maintained exactly during the coupling process. In order to ensure that the execution of the manoeuvre depends as little as possible on the technical equipment of the preceding or receiving aircraft, DLR has developed a way of transferring part of the required technology to an automatic coupling unit located at the end of the tow rope. This allows the catch basket to be actively controlled and operated. The intelligent coupling unit has many attributes of a conventional unmanned aircraft, as an autopilot system uses visual information, for instance, to head for aerodynamically effective control surfaces in order to reduce its distance and relative speed in relation to the receiver aircraft.

The applications of this technology include air-to-air refuelling. It is conceivable that the pilot could be supported up to and including a fully automated refuelling process, as the hose locates the tank nozzle on the aircraft automatically.

Similarly, the technology can also be used to capture rocket booster stages by means of powerful unmanned towplanes, and returning them to Earth undamaged for further use.

German Aerospace Center (DLR)

Stefan Krause · E-Mail: ·