2nd International Planetary Caves Conference (2015) 9036.pdf

MOONRAKER AND TETRIS: JAPANESE MICROROVERS FOR LUNAR CAVE EXPLORATION. Kazuya Yoshida1, Nathan Britton1, John Walker1, 1Space Robotics Laboratory, Tohoku University, Aoba 6-6-01, Sendai, Japan, [email protected] Toshiro Shimizu2, Toshiki Tanaka2 and Takeshi Hakamada2, 2ispace technologies inc., Azabudai, Minato-ku, Tokyo, Japan

Abstract: A Japanese team HAKUTO, led by the [3] Robinson, M. S., Ashley, J. W., Boyd, A. K., Space Robotics Laboratory of Tohoku University is Wagner, R. V., Speyerer, E. J., Hawke, B. R., ... & van developing a low-cost microrover system for explora- der Bogert, C. H. (2012). Confirmation of sublunarean tion of Lunar lava tubes. The development project is voids and thin layering in mare deposits. Planetary and motivated by Google Lunar XPRIZE (GLXP). The Space Science, 69(1), 18-27. prize requires 500 m travel on any surface of Moon, [4] Kazuya Yoshida, Nathan Britton, and John but the team is interested in going down through a sky- Walker, "Development and Field Testing of Moon- light into undiscovered geological structures under- Raker: a Four-Wheel Rover in Minimal Design." The neath the lunar surface. Proc. of the 12th International Symposium on Artificial Skylights are collapses that occur over subsurface Intelligence, Robotics and Automation in Space (i- caverns or lava tubes. First three such holes were dis- SAIRAS), 17-19 June 2014, Montreal, Canada. coveres by Japan’s Kazuya orbitor in Malius Hill, Mare Tranquillitatis and Mare Ingenii [1][2] and more holes were identified by USA’s LRO mission [3]. These places are considered important targets for fu- ture lunar exploration and possible human habitation. The rover system is composed by a four-wheeled rover, Moonraker (Fig. 1) and a two-wheeled rover Tetris (Fig. 2). The total mass of the system is designed to be less than 10 kg [4]. Both rovers are connected by a tether and travel in tandem to approach to a lunar skylight, then on its edge, Moonraker stays as an an- chor and Tetris will go down into the hole. See Fig. 3 Fig,1 Moonraker Pre-Flight Model for a schematic illustration. The team HAKUTO developed a proof-of-concept model (Engineering Model) of rovers in 2013 and a pre-flight model (PFM) using flight-ready components in 2014, then conducted extensive realistic field tests in a sand dune area in Hamamatsu, Japan. The team is currently working with Astrobotic Technology, an American team challenging to the GLXP based in Pittsburg, to land together in the vicinity of a skylight in Lacus Mortis. HAKUTO and Astrobotic Technology Fig. 2 Tetris in tethered down-cliff operation will compete on Moon for the goals of the GLXP, but

then cooperate for cave exploration.

References: [1] Haruyama, J., Hioki, K., Shirao, M., Morota, T., Hiesinger, H., van der Bogert, C.H., Miyamoto, H., Iwasaki, A., Yokota, Y., Ohtake, M., Matsunaga, T., Hara, S., Nakanotani, S., Pieters, C.M.: Possible lunar lava tube skylight observed by SELENE cameras. Ge- ophys. Res. Let. 36, L21206 (2009), doi:10.1029/2009GL040635 [2] Haruyama et al., New discoveries of lunar holes in Mare Tranquillitatis and Mare Ingenii. 41th Lunar Planetry Science Conference, #1285, 2010. Fig.3 A schematic illustration of the downhole exploration