Future space exploration missions envisage feats ranging from in-orbit rendezvous and docking to precise and safe landing on planetary bodies. These missions will not only take place in the vicinity of Earth and Moon but also stretch out several astronomical units to targets like Mars, asteroids, or the icy moons of Jupiter and Saturn. A reliable execution of such maneuvers can only be achieved by autonomous spacecraft using the target body as a navigation reference. Optical navigation methods are seen as a promising tool for realizing this approach. Not surprisingly highly detailed information about the mission target is required. One major class of data providing such information encompasses the results of modern mapping missions, which provide high-quality, high-resolution, global geo-referenced maps, necessary for e.g. precise navigation. A second class comprises data acquired during the mission, for that an obvious application is gathering the live-information necessary to refer to on-board maps for determining the spacecraft’s current position. Another frequent application is building a high-resolution map of the landing site based on real-time 3D measurements of the underlying surface, taken during the final approach.
In any case, this introduces the need for significantly improved online processing capabilities as well as for novel algorithms and optical sensors.
A collaboration of the GNC systems department and other DLR institutes is developing a navigation system which integrates inertial sensors with novel optical navigation sensors. The vision is to develop a navigation system enabling the autonomous, precise and safe landing on the Moon.
The sensor suite comprises an IMU, star tracker, cameras, altimeter and a flash lidar, generating inputs for algorithms such as sensor data fusion, crater navigation, feature tracking and stereo data generation or landing site evaluation.
Overview of the sensor suite of the navigation system
After the successful demonstration of the integrated system during the flight test campaigns, the next project goals are the optimization of algorithms with regards to flight software requirements as well as the layout of breadboards suitable for space operations qualification.