BioBot: Innovative Offloading of Astronauts for More Effective Exploration: NIAC Phase 2 Final Report

Human exploration of the Moon and, eventually, Mars is primarily driven by the capabilities and limitations of the spacesuit and portable life support system (PLSS). Apollo astronauts were limited by the A7L-series pressure garments to using long-handled tools to interact with the lunar surface, as the suits were not flexible enough to allow them to reach their hands directly to the surface without significant effort. While theory indicates an unencumbered human should be able to leap five meters or higher on the Moon, the Apollo astronauts were limited to short shuffling or loping gaits by the weight of the pressure garment and PLSS.

At the time of the original proposal to NIAC, the situation with suit weight for Artemis appeared to be even worse than Apollo. Proposers to the Human Landing System competition were directed to assume that each extravehicular suit would have a mass of 187 kg, which broke down into 83 kg for the pressure garment and 103 kg for the PLSS. This means the typical astronaut would find their body mass tripled for lunar surface activities, with the majority of the extra mass in the life support system carried on their back.

The first extravehicular activities were performed with an umbilical supplying consumables to the suit. For the U.S. program, this included the Gemini and Skylab programs. There was some consideration of using umbilicals for Apollo lunar exploration, which would have limited the crew to the immediate vicinity of the lunar module. Umbilicals are difficult to handle and stow, and would run the risk of dragging and snagging on the surface if untended. In the end, the backpack-based portable life support system was developed, which freed the suits from the vicinity of the lunar module and enabled the extensive EVA exploration of the Apollo program.

The genesis of the BioBot project was a reflection of the projected weight for the Artemis pressure garment and PLSS, with the accompanying impact on the astronaut’s mobility, workload, and safety. The J-series Apollo missions (15, 16, and 17) clearly demonstrated the utility of the lunar roving vehicle to provide greater surface mobility, which expanded the feasible exploration area by more than an order of magnitude. At the same time, in the half century since Apollo, robotic capabilities have grown exponentially, and it seemed likely that robotic manipulators could provide the necessary dexterity for autonomously handling the umbilical in support of lunar surface EVAs. Similarly, robot mobility has grown to the point that autonomous control algorithms should allow a rover to closely follow the astronaut on the surface to stay within reach of the umbilical handling system. The last piece to fall into place was the capability to design and develop a rover which is capable of safely traversing any surface which an astronaut would be able to traverse walking in a spacesuit. Given a system which meets those capabilities, the resulting system could relieve the lunar explorer of the weight and bulk of the PLSS, reducing workload and enhancing mobility. This, then, was the birth of the BioBot concept.