Modelling ATV-TDRSS communications at the international space station

Introduction This article describes an efficient way to model the radiation of S-band quadrifilar helix antennas mounted on the ATV and operating when it docks with the ISS. This electromagnetic modelling is particularly critical because of the overall dimensions of the ATVISS system vis-a-vis the S-band wavelengths and the continuous rotation of a number of solar-generator and thermal-radiator panels to track the Sun’s position. The ISS is currently being assembled in orbit around the Earth (Fig. 1) and, when completed around 2006, the huge complex will be the largest ever structure in space, stretching over 100 metres and sprawling across an area the size of a modern football stadium.