Revised solar-power budget for Cool Robot polar science campaigns

Why develop polar robots? Logistics costs predominate polar-science budgets to maintain safe human operations in extreme environments. Robots could reduce this logistics burden and thus expand research opportunities in the Polar Regions.With the funding from the National Science Foundation, we have developed first ground vehicle specifically designed to conduct long-duration autonomous science campaigns over terrestrial ice sheets. The 60-kg, solar-powered Cool Robot measures 1.2 × 1.2 × 1 m and can carry or tow 20–80 kg science payloads. A low-profile, four-wheel-drive chassis supports a five-sided, lightweight box of solar cells that capture significant reflected sunlight from the snowfield. The robot is zero emissions, so it can conduct clean snow and air measurements without being trailed by its own pollutants. A fleet of Cool Robots could support many other polar science projects, including biological sampling, glaciology surveys, and upper atmosphere or magnetosphere observations using broadly spaced instrument arrays.We present here revisions to the Cool Robot's solar-power input model to account for the effects of diffuse-sky radiation, a significant source of radiation for cloudy conditions common in Greenland. The main effect of increasing diffuse-sky radiation, for fixed global radiation, is to increase the diurnal variation in solar-power input to the robot. The revised model agrees well with irradiance measurements and the robot's measured power budget during a long-duration test conducted in Greenland. It thus allows us to adapt the Cool Robot to the specific needs of polar science campaigns with some confidence. For two-month science campaigns in Antarctica or Greenland, the Cool Robot has sufficient power margin to carry a 20-kg payload, or tow an 80-kg sled, over 1000 km per month. Under most conditions, 100–300 W are available to power the payload. The robot must yet demonstrate reliable long-distance operation. Nevertheless, results to date suggest it holds the potential to conduct significant autonomous science campaigns in Antarctica and Greenland.