Spacecraft Formation about a Keplerian Orbit

• Main Authors: Shin-Ju Li, 李欣儒
• Other Authors: Fu-Yuen Hsiao
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/73135799127987223081

碩士 === 淡江大學 === 航空太空工程學系碩士班 === 95 === This thesis investigates relative trajectories about a Keplerian orbit with potential applications to the formation flight of spacecraft. We first consider a spacecraft formation about a nominal Keplerian orbit, whose dynamics is usually described by the Tschauner-Hempel Equation (T-H Equation). Briefly reviewing the results from the T-H Equation, we analytically prove the applicability of the “local time approximation” to the T-H Equation. With the guidance of local time approximation, we propose potential design methods of control law both in the time domain and in the true-anomaly domain. By designing the control law in the true-anomaly domain, we not only stabilize the unstable relative trajectory, but also“re-construct” the “scaled” nominal orbit for our formation of spacecraft. We also present another methodology for determining relative motion initial conditions for periodic motion in the vicinity of a Keplerian orbit. In this method the spacecraft relative dynamics is derived by subtracting two neighborhood orbits, and simplifying the results. Our work avoids solving the linearized differential equations, and provides a more precise approximation to the relative motion than the T-H Equation did. This result can be used for lowering down the fuel usage for relative orbit maintenance. Numerical simulations are also presented to verify our results.