A Mapping Balloon for Future Robotic and Human Lander Missions to Mars

NASA's 2004 Mars Exploration Rovers (MER) have greatly advanced our understanding of Mars and set new standards in surface exploration. The twin rovers "Spirit" and "Opportunity" have been the first Landers on Mars with a mobility enabling them to look what is hiding behind the horizon. That mobility is a great achievement but also poses new problems. Choosing an initial drive direction after landing is somewhat a gamble since "scientific sweet spots" might be lurking just behind the Rover's horizon in the opposite direction. Surface observations from orbit are much advanced since the times of Viking and have proven to be of great value in determining surface features that are both areas of high scientific interest and safe landing sites. However, the spatial resolution of orbital cameras is insufficient to resolve spots of potential scientific interest at meter and sub-meter scale. The famous Opportunity Ledge outcrop, hidden in a ~ 20 m diameter crater, might have been missed had Opportunity not performed its "hole in one" landing inside that very crater. To close that gap between resolution from orbital observations and the rover's view on future mobile Landers on Mars we propose a simple Mapping Balloon carrying a high-resolution stereo camera. Using the MER concept of a static landing platform from which the rover egresses, the Mapping Balloon would be attached to the landing platform to not compromise the mobility of the rover. The Mapping Balloon would rise up to 100 m above the surface enabling the stereo camera to characterize the landing site beyond the rover's horizon in 3D and at sub-meter scale. Such a map will also help with the precise localization of the landing site. Future human exploration will offer even greater mobility than MER or future robotic rovers. In that scenario the Mapping Balloon would also function as a beacon for orientation, guiding future explorers back to their habitat. It could also serve as radio relay should surface features obstruct direct communications with the habitat.