Scattering interference from large spacecraft and causal effects on launch vehicle antenna performance

Abstract

In this work, we investigate after the performance of an S-band, circularly polarized patch antenna installed on a Launch Vehicle (LV) compromised by the launching spacecraft structure and the unpredicted loss of critical telemetry. During any space launch, on-board Radio Frequency (RF) Telemetry, Tracking & Command (TT&C) systems must satisfy RF link requirements for monitoring of launch vehicle system health, and trajectory tracking for launch range safety. Preprogrammed flight manoeuvres attempt to provide best line-of-sight (LOS) visibility to scheduled receiving satellite and ground stations along the launch trajectory path. Traditional link margin analysis conservatively predicts telemetry margin using measured element radiation patterns for scheduled stations that are in the view. Using advanced computational electromagnetic modelling methods, the compromised radiation pattern is investigated and the causal effect on LV telemetry performance is discussed after the fact without the need for integrated system testing.