Landing amidst slopes and stones

The landing of Apollo 11’s Lunar Module on the moon was done partly by hand. In the future, spacecraft will have to be able to land autonomously on uncharted territory on a moon or planet. Dr Svenja Woicke developed the software.

The landing of Apollo 11’s Lunar Module on the moon was done partly by hand. In the future, spacecraft will have to be able to land autonomously on uncharted territory on a moon or planet. Dr Svenja Woicke developed the software. 

The first moon landing is still a thrill to watch. You hear the altitude readings going down: 2,000 feet, 1,600 feet, 540 feet. Meanwhile, the grey moon surface comes closer and closer. It seems the landing computer reached overload during the descent, after which the astronauts had to take over the helm. Luckily they had extensively trained on a jet-powered floating platform for a manual landing.

Later landings, such as the landings on Mars and Venus, were done on selected clean and flat areas. But, says Woicke in her PhD thesis a flat and spotless terrain isn’t very interesting for scientists. The challenge, says Woicke, is to develop an autonomous landing system that strikes a balance between the dreams of planetary scientists and the fears of engineers. 

Her landing system consists of two parts. The detection part images the planetary surface with stereo vision. It autonomously detects slopes and obstacles larger than two metres. Woicke tested her robot vision system at the Tron-facility at the German space organisation DLR. Despite the realistic problems with camera noise and hard slant lighting, the system overlooked dangerous obstacles in only 2.5% of the tests.

The second part of the landing system uses the automated obstacle detection to navigate to a safe area. In the tests at Tron, a landing area of 60 by 60 metres is the standard. Woicke’s system works much more precisely – it requires only 9 by 6 metres. Besides that, the landing system also overcame nearly all errors in altitude readings. 

Woicke’s Hazard Relative Navigation will enable a robot to land autonomously on an uncharted moon or planet. A modern-day moon landing would be a lot less nerve racking than it was in 1969.