Dropship Offer Safe Landings for Rovers

The dramatic conclusion to ESA¡¯s latest StarTiger project: a ¡®dropship¡¯ quadcopter steers itself to lower a rover gently onto a safe patch of the rocky martian surface.

StarTiger¡¯s Dropter project was tasked with developing and demonstrating a European precision-landing capability for Mars and other targets.

The Skycrane that lowered NASA¡¯s Curiosity rover onto Mars showed the potential of this approach, precisely delivering rovers to their science targets while avoiding rock fields, slopes and other hazards.

¡°StarTiger is a fresh approach to space engineering,¡± explains Peter de Maagt, overseeing the project. ¡°Take a highly qualified, well-motivated team, gather them at a single well-equipped site, then give them a fixed time to solve a challenging technical problem.¡±

This latest team was hosted at Airbus Defence & Space¡¯s facility in Bremen, Germany, joined by engineers from the German Research Center for Artificial Intelligence, Portgual¡¯s Spin.Works aeronautics company, and Poland¡¯s Pozna¨½ University of Technology Institute of Control and Information Engineering.

Starting from scratch for the eight-month project, the Dropter team was challenged to produce vision-based navigation and hazard detection and avoidance for the dropship.

It has to identify a safe landing site and height before winching down its passenger rover on a set of cables.

Flying to a maximum height of 17 m, the dropship comes gently down to 10 m above the ground, where it begins lowering the rover on a 5 m-long bridle, coming lower until the rover touches down. Then it returns to a safe altitude.

Flight testing took place at Airbus¡¯s Trauen site in northern Germany, which back in the 1940s was the scene of spaceplane pioneer Eugen S?nger¡¯s rocket experiments.

A 40 m by 40 m Mars-scape was created, littered with hazardous rocks, where the dropship had to pick a safe spot to deliver its passenger.

The dropship was customised for the project from commercial quadcopter components, with a smaller drone used for preparatory indoor testing.

Using GPS and inertial systems to fly into position, it then switched to vision-based navigation supplemented by a laser range-finder and barometer to land its rover autonomously.

This demonstration having proved the concept, the dropship approach is now available for follow-on development by planetary missions to come.

Source: ESA