In July, I joined a team from Johnson Space Center and elsewhere in investigating the geology of Apollo Valley with rover-deployed scientific instruments. Apollo Valley is a former 1960s Apollo-era astronaut training site at 3,505 meters (11,500 feet) on Mauna Kea, Hawaii. The project was funded by NASA's Moon and Mars Analog Mission Activities Program, which funds projects that simulate scientific, robotic, and human aspects of exploring the Moon and Mars, with the goal of designing the most effective, efficient, and well-integrated future missions. With plentiful basalt lava flows and cinder cones in a dry, barren environment, Mauna Kea is a good analog for the Moon and Mars. Reworking of rocks by ice and water provides another analogy to likely Mars processes. I led the ground-penetrating radar (GPR) investigation, with the radar antenna mounted off the back of the rover. Other rover-mounted instruments included panorama and video cameras, a Moessbauer spectrometer, and navigation instrumentation. By sending radar waves into the subsurface and detecting their reflections off objects and layers and different materials, GPR provides a view of the upper 3-6 meters (10-20 feet) of the subsurface. We were able to trace surrounding lava flows under the bouldery valley fill to some extent, from which we can estimate the volume of material filling the valley. Also evident were multiple layers of cinders, sands, and gravels that sometimes interfingered or truncated against each other, suggesting multiple episodes of material movement (by wind, water, or mass wasting) and different source directions. Another important aspect of the project was the pre-field planning and post-field data analysis based solely on rover-collected data, by scientists who were not in the field, to determine how to improve planetary geologic exploration and science return from remote, robotic operations. The rover itself (~272 kg. or 600 lbs. with four ~40 centimeter- or 16 inch-diameter wheels treaded with small metallic plates) was developed by a Canadian company, Ontario Drive and Gear, in coordination with the Canadian Space Agency, with a view towards future planetary surface missions. The rough lava surfaces, bouldery terrain, and slopes at the site provided grueling physical tests of particular interest to the rover's engineering and design team. The rover turned in an impressive performance, proving to be quite capable on terrains far rougher than traversed by the rovers currently on Mars. Patrick Russell is a geoscientist in the Center for Earth and Planetary Studies at the National Air and Space Museum.