This paper describes the orbit design of the deployable payload Rover 2 of MINERVA-II, installed on the Hayabusa2 spacecraft. Because Rover 2 did not have surface exploration capabilities, the operation team decided to experiment with a new strategy for its deployment to the surface. The rover was ejected at a high altitude and made a semi-hard landing on the surface of the asteroid Ryugu after several orbits. Based on the orbital analysis around Ryugu, the expected collision speed was tolerable for the rover to function post-impact. Because the rover could not control its position, its motion was entirely governed by the initial conditions. Thus, the largest challenge was to insert the rover into a stable orbit (despite its large release uncertainty), and avoid its escape from Ryugu due to an environment strongly perturbed by solar radiation pressure and gravitational irregularities. This study investigates the solution space of the orbit around Ryugu and evaluates the orbit’s robustness by utilizing Monte Carlo simulations to determine the orbit insertion policy. Upon analyzing the flight data of the rover operation, we verified that the rover orbited Ryugu for more than one period and established the possibility of a novel method for estimating the gravity of an asteroid.
- r = [x, y, z]:
position vector and its elements in cartesian coordinates
- a G = [a Gx, a Gy,a Gz]:
normalized gravitational acceleration
- e r :
eccentricity of asteroid’s orbit
- a r :
semi-major axis of asteroid’s orbit (m)
- f r :
true anomaly of asteroid’s orbit (rad)
- U :
normalized gravity potential associated with asteroid harmonics
- d :
distance between the Sun and asteroid
- β :
normalized acceleration by solar radiation pressure
- a SRP :
unnormalized acceleration by solar radiation pressure (m/s2)
- γ :
- p 0 :
solar flux constant (kg · m/s2)
- m :
mass of the rover (kg)
- A :
projected area of the rover (m2)
- μ S :
gravitational parameter of the Sun (m3/s2)
- μ :
gravitational parameter of the asteroid (m3/s2)
- P :
- l, m :
order and degree of harmonics taken into account
- C lm,S lm :
- ϕ :
latitude in asteroid fixed frame (rad)
- λ :
- n :
mean motion (rad/s)
- Cj :
Jacobi integral (m2/s2)
- v c :
critical velocity (m/s)
- v o :
circular orbit velocity in two-body problem (m/s)
- v m :
velocity margin (m/s)
- a :
semi-major axis of spacecraft’s orbit (m)
- e :
eccentricity of spacecraft’s orbit
- I :
inclination of spacecraft’s orbit
- W :
longitude of the ascending node of spacecraft’s orbit
- w :
augment of periapsis of spacecraft’s orbit
- f :
true anomaly of spacecraft’s orbit
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This work was partially supported by JSPS KAKENHI Grant (No. 18H01628).
Yusuke Oki is a researcher at Japan Aerospace Exploration Agency (JAXA). He graduated with a master degree in astronautics from the University of Tokyo in 2016, and with a Ph.D. degree in astronautics from the University of Tokyo in 2019. He joined JAXA in 2019, and has been working on system design and orbit design of spacecrafts. His current research interests are astrodynamics, concurrent design, and deep space exploration. E-mail: email@example.com.
Kent Yoshikawa received his bachelor and master degrees in engineering from Tokyo Institute of Technology in 2013 and 2015, respectively. From 2015, he has been working as an engineer in Research and Development Directorate, JAXA. His current research interests include astrodynamics, GNC, planetary robotics, and planetary exploration. E-mail: firstname.lastname@example.org.
Hiroshi Takeuchi received his Ph.D. degree of science (physics and applied physics) from Waseda University in 2000. In 2006 he started working at Institute of Space and Astronautical Science (ISAS)/JAXA as a member of deep space orbit determination group. He was a visiting researcher of the NASA Jet Propulsion Laboratory in 2012–2013. He is currently an associate professor of ISAS/JAXA and is also the lead of the orbit determination of Hayabusa2. His current research interest is developing the deepspace multi-objects orbit determination system. E-mail: email@example.com.
Shota Kikuchi received his Ph.D. degree in aeronautics and astronautics from the University of Tokyo in 2018. From 2015 to 2017, he served as a visiting scholar at Purdue University and NASA Jet Propulsion Laboratory. He is currently a postdoctoral research associate at JAXA and is engaged in the Hayabusa2 asteroid sample return mission as a system engineer. His primary research interests lie in the field of astrodynamics, particularly in the dynamics around small bodies. E-mail: firstname.lastname@example.org.
Hitoshi Ikeda received his Ph.D. degree from Kyusyu University, Japan, in 2008. He is a researcher at Research and Development Directorate, JAXA. He is involved in Hayabusa2 project as a radio science researcher. His research interests include astrodynamics, orbit determination, mission design, and flight dynamics operation. E-mail: email@example.com.
Daniel J. Scheeres is a distinguished professor in the Smead Department of Aerospace Engineering Sciences, University of Colorad. He holds degrees from the University of Michigan and Calvin College. Prof. Scheeres is a member of the National Academy of Engineering, a fellow of the American Institute of Aeronautics and Astronautics and of the American Astronautical Society.
Jay McMahon is an assistant professor in the Smead Aerospace Engineering Sciences department at the University of Colorado Boulder, where he heads the ORCCA Laboratory. He earned his Ph.D. degree from the University of Colorado Boulder, an M.S. degree from the University of Southern California, and a B.S. degree from the University of Michigan. He is an associate fellow of the American Institute of Aeronautics and Astronautics. E-mail: firstname.lastname@example.org.
Junichiro Kawaguchi received his doctor degree of engineering from The University of Tokyo in 1983. He got the full professor position at ISAS in 2000. He had been the Project Manager of the Hayabusa mission since 1996 till 2011. He is currently at senior fellow position, JAXA. He was the president of Japan Society for Space and Astronautical Science. And he also served Secretary General at the Strategic Headquarters for Space Policy’s, Cabinet Secretariat, Government of Japan. He had been a full member and has been a corresponding member at the Science Council of Japan, Government of Japan. He has been a fellow at the Japan Society for Space and Astronautical Science. He has been a full member, board of Trustee at the International Academy of Astronautics.E-mail: email@example.com.
Yuto Takei received his Ph.D. degree in mechanical and aerospace engineering from Tokyo Institute of Technology, Japan, in 2015. He served as a visiting scholar at Institute of Robotics and Mechatronics of German Aerospace Center (DLR) in 2013. He is currently a researcher at Research and Development Directorate, JAXA. He is involved in Hayabusa2 project as a systems engineer. His research interests include astrodynamics, spacecraft system, space robotics, and deep space exploration.E-mail: firstname.lastname@example.org.
Yuya Mimasu is a researcher at JAXA. He graduated with a Ph.D. degree in aerospace engineering from Kyushu University. After graduation he joined JAXA, and has been working on guidance, navigation and control subsystem of Hayabusa2 mission which is JAXA’s sample return mission from the asteroid. His research interests are astrodynamics and mission analysis around the small body.E-mail: email@example.com.
Naoko Ogawa received her B.E., M.E. and Ph.D. degrees in mathematical engineering and information physics in 2000, 2002, and 2005, respectively, from the University of Tokyo, Japan. From 2004 to 2008, she has been a research fellow of the Japan Society for the Promotion of Science. Since 2008 she has been a research engineer at ISAS, JAXA. Her current research interests include astrodynamics, mission design, robotics, spacecraft systems and operation.E-mail: firstname.lastname@example.org.
Go Ono is a researcher at JAXA. He graduated with a master degree of engineering from the University of Bath in 2011 and a Ph.D. degree in aerospace engineering from the University of Tokyo in 2014. He joined JAXA in 2015, and has been working on guidance, navigation, and control systems of JAXA’s deep space missions such as Hayabusa2 and MMX. His current research interests are astrodynamics and deep space exploration.E-mail: email@example.com.
Fuyuto Terui received his Ph.D. degree in aerospace engineering from University of Osaka Prefecture in 1989. He has been a staff member of Space Technology Research Center of National Aerospace Laboratory (NAL) of Japan since 1989. He was a visiting scholar of University of Cambridge, Engineering Department, Control Group between 1994 and 1995. After the reorganization of space agencies in Japan, he has been a staff member of JAXA since 2003, and is now a function manager of “Hayabusa2” project as well as a representative of Attitude and Orbit Control System of “Hayabusa2” spacecraft. His main research field is robust control and image-based guidance, navigation, and control of a spacecraft such as debris removal space robot and the asteroid exploration probe.E-mail: firstname.lastname@example.org.
Manabu Yamada received his Ph.D. degree in Earth and planetary sciences from Hokkaido University, Japan, in 2006. He is a staff scientist at Planetary Exploration Research Center (PERC), Chiba Institute of Technology. He is now involved in Hayabusa2 project. He was a developer of the Optical Navigation Camera (ONC) system. His research interests include planetary atmospheres, remote sensing, and deep space exploration.E-mail: email@example.com.
Toru Kouyama is a senior researcher at National Institute of Advanced Industrial Science and Technology (AIST). He graduated with a master degree in Earth and planetary science from the University of Tokyo in 2008, and with a Ph.D degree in Earth and planetary science from the University of Tokyo in 2012. He has entered AIST in 2012, and has been working on remote sensing research and satellite sensor calibration. His current research interests are planetary science, remote sensing, and deep space exploration.E-mail: firstname.lastname@example.org.
Shingo Kameda is a professor in Rikkyo University. He graduated with a master degree in science from the University of Tokyo in 2004, and with a Ph.D. degree in science from the University of Tokyo in 2007. He joined Rikkyo University in 2011 and has been working on development of scientific instruments onboard spacecraft for solar system exploration. His current research interest is planetary science.E-mail: email@example.com.
Kazuya Yoshida received his D.Eng. degree in mechanical engineering science from Tokyo Institute of Technology in 1990. Since 2003 he has been a full professor in Department of Aerospace Engineering, Tohoku University, Japan. His research field is space robotics and he has been contributing to space engineering education for international students at International Space University in Strasbourg, France.
Kenji Nagaoka received his B.E. degree in aerospace engineering from the Tokyo Metropolitan Institute of Technology, Japan, in 2006. He also received his Ph.D. degree from the Graduate University for Advanced Studies (SOKENDAI), Japan, in 2011. From 2011 to 2019, he had been an assistant professor in the Department of Aerospace Engineering, Tohoku University, Japan. Since 2019, he has been an associate professor in the Department of Mechanical and Control Engineering, Kyushu Institute of Technology, Japan. His current research interests include space robotics, such as on-orbit servicing robots and planetary rovers.E-mail: firstname.lastname@example.org.
Tetsuo Yoshimitsu received his B.E., M.E., and D.E. degrees in electrical engineering from the University of Tokyo in 1992, 1994, and 2000, respectively. He is currently an associate professor at ISAS, JAXA. He was the principal investigator of MINERFVA payload in Hayabusa asteroid sample return mission. He has been the principal investigator of MINERVA-II rovers in Hayabusa2 mission, which achieved the world-first robotic mobile exploration on small planetary body. His research interests lie on robotic exploration system and control in space, such as planetary rovers, mobile system, path planning over natural terrains, localization on planetary surface and autonomous exploration system.
Takanao Saiki received his Ph.D. degree in aeronautics and astronautics from the University of Tokyo, Japan, in 2005. He is an assistant professor at ISAS, JAXA. He is now involved in Hayabusa2 project. He was a chief developer of the impact system and he is currently a project engineer. His research interests include astrodynamics, spacecraft system, and deep space exploration.E-mail: email@example.com.
Yuichi Tsuda received his Ph.D. degree in aeronautics and astronautics from University of Tokyo in 2003, and joined JAXA in 2003 as a research associate. He was a visiting scholar of Department of Aerospace Engineering, University of Michigan and Department of Aerospace Engineering Sciences, University of Colorado Boulder in 2008–2009. He was a deputy lead of the IKAROS project, the world’s first interplanetary solar sail mission. He is currently a professor of ISAS/JAXA and is also the project manager of the Hayabusa2, an asteroid sample-return mission. His research interests are astrodynamics, spacecraft system, and deep space exploration.E-mail: firstname.lastname@example.org.
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Oki, Y., Yoshikawa, K., Takeuchi, H. et al. Orbit insertion strategy of Hayabusa2’s rover with large release uncertainty around the asteroid Ryugu. Astrodyn 4, 309–329 (2020). https://doi.org/10.1007/s42064-020-0080-y
- solar radiation pressure
- augmented elliptic Hill three-body problem
- gravitational irregularity