Development of the Orlan space-station antenna

The design of the Crew-Lock antenna for the Russian communication and data system [for the international Space Station] was challenging, because it is enclosed in a conducting shell. In addition, the electromagnetic-field dis tribution within the Crew Lock is highly constrained by the lowest one or t wo normal modes of the structure. Two kinds of antennas were investigated t o address the requirements (presented in Section 2). a half loop and a load ed patch. Computer modeling of these approaches was done by the Finite-Elem ent and Moment Methods, respectively (Section 3). The loop antenna underwen t extensive scale-model testing, and some full-scale tests at Johnson Space Center in Houston (Section 4). The patch antenna was eliminated during the hull-scale tests. The final design is the "towel-bar" loop, which performs the additional function of a handrail for astronauts during the ingress an d egress for extra-vehicular activity (EVA).