Interster was a weekly science-fiction Supermarionation television show made for children and shown in South Africa from the late 1970s. South African Broadcasting Corporation children's programming was quite innovative during the late 1970s to early 1980s — the impossibility of purchasing Thunderbirds forced the SABC to produce Interster, but also the technical challenge offered the opportunity to truly flex the SABC's creative muscles.
The main plot involved an undercover planetary defence agency operating from Cape Town under the guise of an interstellar shipping company. The show mirrored the real world political issues of international isolation facing Apartheid South Africa with the Earth being depicted as a galactic pariah of the "Interplanetary League" due to its cold war with the planet "Krokon". The villain in the series was depicted by Prince Karnati or his evil henchmen.
The spaceships used in the show were called Impalas after the South African Air Force aircraft, the locally assembled Italian Aermacchi MB-326. There was a pragmatic reason for calling the aircraft Impalas - the basis of the models were 1/48 scale plastic model kits of the AM326, so that they would be recognisable to South African youth.