a methodology to repair or deorbit leo satellite constellations - AGI

82and, allowing time for actual rendezvous and latch-up, combined SRS-GlobalStarsatellite elements resulted. If a GlobalStar could be repaired, the SRS unit woulddisconnect from it and the SRS propulsion system would be used to propel the SRSonto an appropriate re-entry trajectory. The worst case is when the GlobalStar cannotbe repaired and the combined SRS-GlobalStar ―satellite‖ needs to be removed fromorbit. SRS and non-functional GlobalStar satellite pairs got into de-orbiting trajectory.Also we added a 10% ∆V allowance was added for all rendezvous maneuvers. Thecalculated required ∆V values are shown in Figure 3.24.Table 3.24 Required ∆V to Achieve Rendezvous.25164U25964U25874U25853USRSPLANECHANGE∆V (km/sec)1.70740.932700.5187SRSRENDEZVOUS∆V (km/sec)0.05130.03860.00420.0999REQUIRED ∆V∆VALLOWANCE(km/sec)0.0050.0040.00050.00925306U 1.4624 0.0418 0.005DE-ORBIT ∆V(km/sec)0.41480.39960.39450.43260.4108TOTAL ∆V(km/sec)2.17851.41090.39921.06021.9200We calculated aAll rendezvous were calculuated by using a restricted twobodyproblem analysis and frozen time. In real calculations, the NORAD data must beupdated as close to the actual rendezvous time as possible.3.2.3 Propellant mass and burn time calculations for SRS and Non-functionalGlobalStar satellite de-orbit operationsExcept for the close proximity maneuvers, orbital rendezvous propellant massand maneuver time allowances are required. The rocket equation can be employed toestimate the propellant required for each distinct orbital maneuver tabulated in Tables3.6 and 3.11. That is,∆ ( ) . / (3.15a)where ( ) (3.15b)