Pommer (Paul Frees) is an arrogant and somewhat crazy scientist. He's in charge of an experiment where a space probe (hence the title of the film) is launched to try to capture "space spores". The experiment is a success BUT the spores are deadly. He soon realizes that they could breed uncontrollably and on protein (such as blood or flesh)--yet he continues to work on these spores all by himself in his own private lab--without adequate safeguards in case these spores got loose. And, not surprisingly, they eventually do--consuming the doctor. When this is discovered, the place is burned and fumigated and everyone who came in contact with the place was completely decontaminated....but this might not be enough. A woman, Pommer's lover, was apparently there but has since left. Could she be unknowingly transporting this fungus with her? This so-called "blood rust" has already apparently consumed the surface of Mars--would the Earth, too, soon become the next "red planet"?! I expected that the rest of the film would be an Earth versus the monster sort of thing, but instead of showing giant fungi attacking buildings and civilians, it was instead more of a detective-type movie. Much of the film shows the governmental authorities in their frantic attempts to find this woman. At the same time, she THINKS they are after her about some crime or that the police exposure might tip off the police about her affair--so the harder the authorities try to hunt for her, the harder she tries to vanish! This approach was pretty interesting--a definite improvement over just another monster from space film.
Overall, an interesting sci-fi film that made the idea seem almost possible. Good acting and production values carry this film and make it worth seeing....really...even if the fungi looks pretty weird. The only negative is the use of stock footage of the plane landing--the markings aren't even the same as the plane you see in the film and it even appears to be a different model of plane!
By the way, Paul Frees, while not a household name, is someone you will probably recognize when I tells you why he's famous. While he acted in quite a few films and wrote music for quite a few more, he's most known for his voice work--such as dubbings of films, TV shows (such as playing Boris Badenov on the "Bullwinkle" show) and the voice of the narrator in the haunted mansions at Disneyland and Disney World.
Also, in an odd cameo, Moe Howard of the Three Stooges fame plays a cab driver. He was between contracts and earned a few dollars in this small role.
Review by MartinHafer from the Internet Movie Database.