Accession Number : ADA141173

Title :   Analysis of Electric Propulsion Orbit Transfer Vehicles vs IUS, CENTAUR-G, and a Reuseable Bipropellant System.

Descriptive Note : Master's thesis,


Personal Author(s) : Maddox,L W

PDF Url : ADA141173

Report Date : Dec 1983

Pagination or Media Count : 162

Abstract : A flexible method was developed to optimize electric orbit transfer vehicles (EOTVs) and compare them with baseline chemical systems. EOTVs have been characterized by the thruster technology and the propellant mass versus power supply mass for standardized NASA BIMOD configurations. Baseline chemical systems are represented by the Inertial Upper Stage CENTAUR-G, and a proposed reuseable LOX-LH Centaur derivative. Five electrostatic propulsion thrusters were chosen for optimization. These were the baseline NASA/Hughes 38-cm J-Series Mercury Ion Thruster and four derivatives. Each was characterized through linearization of experimental data. Relationships of input power (KW) to the thruster vs specific impulse and input power vs thrust were developed. The first relationship along with equations for power supply mass and propellant mass were input to the Sequential Unconstrained Minimization Technique (SUMT) nonlinear optimization program. The combination of the propellant mass used for transfer to GEO and return and the power supply mass was minimized. SUMT runs were made for the five thrusters carrying representative payloads from 1 to 6 NavStar GPS satellites with associated masses of 908 to 5448 KG. Transfer times were then calculated for each of these payload optimized EOTV combinations. Of the thrusters chosen, the Ring-Cusp 3-Grid Xenon thruster accomplished the LEO to GEO and return trips with the least mass and the minimum transfer time.

Descriptors :   Space propulsion, *Thrusters, *Electric propulsion, *Space transportation, Transfer trajectories, Space to space, Space shuttles, Comparison, Mission profiles, Parametric analysis, Payload, Specific impulse, Mass, Van Allen radiation belt, Bipropellants, Solar panels, Xenon, Reusable equipment, Spacecraft, Optimization, Trade off analysis, Life cycle costs, Theses

Subject Categories : Electric and Ion Propulsion
      Rocket Propellants
      Unmanned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE