 It was while the Round House (through which Thunderbird 3 would be  launched) that Derek Meddings (qv) realized that the design of the  building was just right for Thunderbird 5, the International Rescue  space station. Unable to come up with a convincing design before  now, this was the last of the five Thunderbird craft that he  created. By adding aerials and transmitters to the Round House, he  developed the series most unusual and effective vehicle, although  it was to play only a minor part in the finished program.