Orbital Dynamics in Strongly Perturbed Environments around Asteroids

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K21075
• Project/Area Number (Other): 18H05901 (2018)
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund (2019); Single-year Grants (2018)
• Review Section: 0301:Mechanics of materials, production engineering, design engineering, fluid engineering, thermal engineering, mechanical dynamics, robotics, aerospace engineering, marine and maritime engineering, and related fields
• Research Institution: Japan Aerospace EXploration Agency
• Principal Investigator: Kikuchi Shota 国立研究開発法人宇宙航空研究開発機構, 宇宙科学研究所, 宇宙航空プロジェクト研究員 (90830068)
• Project Period (FY): 2018-08-24 – 2021-03-31
• Keywords: 探査機 / 軌道設計 / 小惑星 / 摂動 / 太陽光圧 / 重力場

Outline of Final Research Achievements

The orbital motion of spacecraft in the vicinity of asteroids is strongly disturbed and exhibits complex behaviors because of weak and irregular gravitational force. The main focus of this study is the dynamics of spacecraft in the strongly perturbed environment around asteroids. This research first proposed retrograde teardrop orbits, which are made periodic by introducing a deterministic thrusting maneuver within each period to ensure long-term stability. In addition, based on the constructed dynamical model, frozen orbit solutions were identified, in which the orbital elements remain constant even under solar radiation and gravitational perturbations. Another contribution of this research is the trajectory design for the Hayabusa2 precision touchdown incorporating the effect of irregular surface gravity field. Using the designed landing trajectory, Hayabusa2 successfully conducted touchdowns on the asteroid Ryugu in 2019.

Free Research Field

軌道力学

Academic Significance and Societal Importance of the Research Achievements

本研究の成果を応用すると，より高度かつ確実に小惑星探査を行うことが可能となる．小惑星は太陽系形成当初の姿をよく保っていると考えられており，本研究による小惑星探査技術の高度化は，太陽系や生命の起源解明につながり得る成果である．実際に，はやぶさ２では本研究で設計された着陸軌道を用いて，小惑星リュウグウへの2度のタッチダウンに成功しており，小惑星サンプル採取の成功に貢献した．また，惑星科学上の学術的意義のみならず，将来の鉱物資源の獲得や，地球への隕石衝突回避につながり得る点で，本研究の成果は社会的にも大きな意義を持つ．