<h2>AAS 99-180</h2>
<h2>Orbit Attainment and Maintenance for the Geosat Follow-On (GOFO) Satellite                                                                       </h2>
<h4>S. Mitchell                                                                                                                                                                         </h4>
Ball Aerospace and Technologies Corporation, Boulder, CO                                                                                                                  
<h2> Abstract </h2>
Geosat Follow-On (GFO) is a Navy satellite mission to study physical oceanography. The GFO satellite operates in the Geosat Exact Repeat Orbit (ERO) (approximately 800 km altitude, 108 degree inclination, 0.001 eccentricity), whose ground track repeats to within 1 km every 244 orbits in 17 days. This paper will describe the process of attaining and maintaining the spacecraft in the ERO. Plot showing the orbit attainment process will be presented, and experience described. The software used to monitor and design maneuvers to maintain the ground track location will be described. Experience gained in topic such ass maintaining the ERO and thruster calibration for small maneuvers will be described.