ブックタイトル東北大学　アニュアルレビュー2015(英語版)

概要

東北大学　アニュアルレビュー2015(英語版)

Kazuya YoshidaRising into SpaceThe Space Robotics Laboratory at Tohoku University has sent microsatellites into orbitand hopes to soon land a robot on the Moon.Tohoku University’s Space Robotics Laboratory, in partnership with HokkaidoUniversity, developed the 43-kilogram, cube-shaped microsatellite Rising-2.At midday on May 24, 2014, Professor Kazuya Yoshidaand his colleagues at Tohoku University’s Space RoboticsLaboratory held their breath as a rocket from the JapanAerospace Exploration Agency took off from the smallisland of Tanegashima.The laboratory had a lot riding on the mission. Onboard was a small cube-shaped microsatellite called Rising-2,which the Tohoku team and a group from HokkaidoUniversity had built over the previous five years. The teamcould not forget how its predecessor, Sprite-Sat, alsoknown as Rising-1, had suffered irreparable damage to itscontrol system on the ill-fated thirteenth day in orbit.Named after Raijin, the Japanese god of lightningand thunderstorms, both Rising 1 and 2 were designedto study‘sprites’? bright-red electromagnetic burststhat flash above thunderclouds. Observing this elusivephenomenon could help scientists better understand thepotentially disastrous heavy downpours that have beendubbed‘guerilla rain’.“Microsatellites have been a game-changing conceptfor space research,”explains Yoshida, who foundedthe Space Robotics Laboratory in 1995. Instead of relyingon national space agencies to engineer large spacecraft,small university laboratories can now build tiny spacereadysatellites quickly and inexpensively, allowing themto conduct meaningful scientific reconnaissance.Research HighlightMicrosatellite Rising-2 was propelled into space by a rocket from the JapanAerospace Exploration Agency on May 24, 2014. cJAXAA high-resolution remote sensing image of the rice field area of Miyagi prefecture,Japan, obtained by Rising-2 with 5m ground sample distance (GSD).cTohoku University/Hokkaido UniversityRISING-2 Landsat-8 Google EarthA comparison of the“vegetation index”map of a rice field area obtained byRising-2 in 5m GSD and Landsa-8 in 30m GSD. cHokkaido University/TohokuUniversitySince its launch, Rising-2 has delivered some of themost advanced images yet achieved by a satellite of itssize, such as the“vegetation index”with 5m resolution ofthe ground surface, which shows the vitality and health ofvegetation on Earth.Asteroid dust and lunar landingsRising-2 is just one of the groundbreaking spaceflightmissions to which Yoshida’s laboratory has contributed.“Very few research groups are as actively involved inreal space missions,”he says. This gives his group’s studentsunique opportunities to get involved in projects withreal-life applications, whether supporting national aerospaceagency initiatives or developing their own satellitesand rovers that could end up in space.Another recent project was the development ofJapan’s asteroid explorer, Hayabusa, which successfullylanded on Itokawa, an asteroid 300 million kilometersaway from Earth at the time. Yoshida helped design themechanism for collecting soil samples from the surface ofItokawa.The successor mission, Hayabusa-2, is currentlyunderway. In early December 2015, Hayabusa-2 successfullyconducted an Earth swing-by, a necessary maneuverto boost its velocity and set it on a course towardsasteroid Ryugu. Hayabusa-2 is expected back on Earth in2020 with sample materials from the asteroid’s surface.Now, Yoshida and his colleagues are taking on theGoogle Lunar XPRIZE challenge, a worldwide competitionfor the first privately funded team to successfullyland and drive a rover 500 meters across the surface ofthe Moon while broadcasting high-definition images backto Earth.Spurred on by the promise of a 20 million U.S.dollar prize, the Space Robotics Laboratory has beenworking on prototypes for the only Japan-based team,Hakuto. Its robots, named MoonRaker and Tetris, havealready been tested on some lunar analog sites on Earth.In January 2015, the team won the prestigious TerrestrialMilestone Prize, worth half a million U.S. dollars,for the development of the rover’s mobile technology.For Yoshida, this project represents a big steptowards fulfilling a personal ambition.“My dream is tosomeday visit the Moon,”he says,“and to get an entirelynew perspective on our Universe.”Since its launch, Rising-2 has deliveredsome of the most advanced images yet achieved by a satellite of its size.MoonRaker(4-wheel rover) in field tests over a sand dune in JapancTohoku University/team HAKUTOKazuya Yoshida is director of the Center of Roboticsfor Extreme and Uncertain Environments(CREATE). He is a professor of mechanical andaerospace engineering.Tetris(2-wheel rover) in down-cliff tests hangingby tether from Moonraker cTohoku University/team HAKUTOTohoku University ANNUAL REVIEW 2015page: 16Tohoku University ANNUAL REVIEW 2015page: 17