Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Engineering
Analytical Solution For Low-Thrust Minimum Time Control Of A Satellite Formation, John Sang-Pil Seo
Analytical Solution For Low-Thrust Minimum Time Control Of A Satellite Formation, John Sang-Pil Seo
Theses and Dissertations
Satellite formations or distributed satellite systems provide advantages not feasible with single satellites. Efficient operation of this platform requires the use of optimal control of the entire satellite formation. While the optimal control theory is well established, only a very simple dynamical system affords an analytical solution. Any practical optimal control problem solves the resulting two-point boundary value (TPBV) problem numerically. The relative satellite dynamics using Hill's coordinate system and approximations made by Clohessy and Wiltshire, combined with body-fixed thruster control, result in a linearized dynamic system. This dissertation provides the analysis for the minimum time satellite formation control by …
Performance Study Of Two-Stage-To-Orbit Reusable Launch Vehicle Propulsion Alternatives, Marc A. Brock
Performance Study Of Two-Stage-To-Orbit Reusable Launch Vehicle Propulsion Alternatives, Marc A. Brock
Theses and Dissertations
This study investigated the performance of five Two-Stage-To-Orbit reusable launch vehicles (RLV), with stages propelled by rocket engines, turbojet engines and Rocket Based Combined Cycle (RBCC) engines. Horizontal versus vertical takeoff launch and direct versus lifting ascent trajectories were also studied. A method was conceived using a 3 degree of freedom optimization program, stage inert mass fractions, and a fixed gross takeoff weight (GTOW) of 1,000,000 lbf to determine each RLVs performance based on payload weight delivered to orbit and total vehicle inert weight. RLV trajectory constraints, mass fractions, engine performance, and aerodynamics were assumed from literature of similar RLVs …