Title: Combined Thermal Control and GNC: An Enabling Technology for CubeSat Surface Probes and Small Robots,
Abstract: Advances in GNC, particularly from miniaturized control electronics,
reaction-wheels and attitude determination sensors make it possible to design
surface probes and small robots to perform surface exploration and science on
low-gravity environments. These robots would use their reaction wheels to roll,
hop and tumble over rugged surfaces. These robots could provide 'Google
Streetview' quality images of off-world surfaces and perform some unique
science using penetrometers. These systems can be powered by high-efficiency
fuel cells that operate at 60-65 % and utilize hydrogen and oxygen electrolyzed
from water. However, one of the major challenges that prevent these probes and
robots from performing long duration surface exploration and science is thermal
design and control. In the inner solar system, during the day time, there is
often enough solar-insolation to keep these robots warm and power these
devices, but during eclipse the temperatures falls well below storage
temperature. We have developed a thermal control system that utilizes chemicals
to store and dispense heat when needed. The system takes waste products, such
as water from these robots and transfers them to a thermochemical storage
system. These thermochemical storage systems when mixed with water (a waste
product from a PEM fuel cell) releases heat. Under eclipse, the heat from the
thermochemical storage system is released to keep the probe warm enough to
survive. In sunlight, solar photovoltaics are used to electrolyze the water and
reheat the thermochemical storage system to release the water. Our research has
showed thermochemical storage systems are a feasible solution for use on
surface probes and robots for applications on the Moon, Mars and asteroids.