The serial is best remembered as one of the first screen appearances of a young Leonard Nimoy, who plays Narab, one of the three Martian invaders. In 1958 a feature film version of this serial, retitled Satan's Satellites, was made by editing down the serial's footage to feature film length.
Larry Martin (Judd Holdren), a leader in the Inter-Planetary Patrol, detects a rocket coming to Earth. He takes to the air in his jet-powered rocket suit and helmet to investigate and discovers Martian invaders, led by Marex (Lane Bradford). Since Mars is now orbiting too far from the Sun and its ecology has been dying, the Martian invaders want to swap Earth's and Mars' orbits, so Mars will then be closer to the Sun. They plan on achieving this by using hydrogen bomb plans stolen from Earth scientists to cause the two planets' orbits to swap, using specifically placed atomic explosions on both worlds. Martin also learns the Martians have Earth accomplices in the forms of the traitorous Dr. Harding (Stanley Waxman), and two gangsters, Roth (John Crawford) and Shane (Ray Boyle), who bedevil him and his associates, Sue Davis (Aline Towne) and Bob Wilson (Wilson Wood).
The Martians set up a base in an underground cave that can only be reached from underwater, where they begin constructing their bomb; and make a remotely-controlled robot to supplement their human associates in acquiring supplies and funds to complete the project. Eventually, Larry and his comrades gain the upper hand: Marex kills Harding when he attempts to surrender, Roth and Shane are killed when Larry turns the robot against them, and the Martians are brought down in flames in their rocket ship after a furious stratosphere raygun battle with Larry in his own spacecraft. Marex's Martian aide, Narab (Leonard Nimoy) survives the crash and tells Larry where to find the underwater cave with the activated bomb in it. Larry arrives in time to defuse the bomb just seconds before it would have exploded.
Zombies of the Stratosphere was scripted as a sequel to the successful "Radar Men from the Moon", which introduced an original semi-superhero, Commando Cody, played by George Wallace; and interrupted production on a planned TV program also built around that character, titled "Commando Cody: Sky Marshal of the Universe", with Judd Holdren now starring as Cody. Then, just as filming began on this serial, the name of the hero was changed from Commando Cody to Larry Martin; but he retains all the same sidekicks (also renamed), high-tech props and laboratory facilities that Commando Cody had in the previous serial, Radar Men from the Moon".
An addition to the Rocket Man back-pack and helmet, used for the first time in this serial, is a two-way radio about the size of a lunchbox; Larry Martin wears it hanging heavily from his belt when dressed for flying. This radio is also seen in some stills of Cody in Commando Cody: Sky Marshal of the Universe. As most flying sequences are reused stock footage from earlier Rocket Man serials, the radio usually disappears when Commando Cody is in flight. Martin also uses an ordinary police revolver instead of the ray gun favored by Cody in earlier and later serials.
Zombies of the Stratosphere was budgeted at $172,838, although the final negative cost was $176,357 (a $3,519, or 2%, overspend). It was the cheapest Republic serial of 1952 and was filmed between April 14, and May 1, 1952. At seventeen days, this is tied with King of the Carnival for the shortest filming period of all Republic serials. The serial's production number was 1933.
Zombies of the Stratosphere reuses the "Republic Robot" (somewhat resembling a walking silvery hot-water heater with two ribbed arms that terminate in pincers), along with stock footage of it in action (such as the Bank Robbery by Robot scene from Mysterious Doctor Satan) and black-and-white footage from a Republic full color Roy Rogers film. The serial is also heavily padded with footage from their King of the Rocket Men (1949), to which this is a pseudo-sequel. Although the Zombies serial has Martians as the villains, they are not the same Martians as shown in the earlier Republic serial The Purple Monster Strikes. The Robot was first seen in Undersea Kingdom (1936) and prominently featured in Mysterious Doctor Satan (1940).Dale Van Sickel as Larry Martin (doubling Judd Holdren)
All the special effects in Zombies of the Stratosphere were produced by the Lydecker brothers, Republic's in-house physical and model effects team. Their flying effects, using a dummy running along a wire, were first used in Republic's Darkest Africa (1936) and with greater impact in their Adventures of Captain Marvel serial (1941).
Zombies of the Stratosphere's official release date is July 16, 1952, although this is actually the date the sixth chapter was made available to film exchanges. This was followed by the release of Commando Cody: Sky Marshal of the Universe, which had been filmed around the productions of Zombies (three episodes before, the remaining nine afterwards) as a projected twelve-part TV series but which was theatrically issued instead. In this latter film, Judd Holdren played a masked Cody and Aline Towne appeared again as Joan Gilbert.
A 70-minute feature film version, created by heavily editing down the serial footage, was released on March 28, 1958, under the new title Satan's Satellites.
Zombies of the Stratosphere was one of two Republic serials later colorized for 1990s television broadcast.
During 1991, the serial was released in original full length and black-and-white on two videodiscs from The Roan Group; in 1995 by Republic Pictures Home Video in the U.S. on VHS edited to 93 minutes and colorized; as a 2-DVD set from Cheezy Flicks Entertainment in 2009 at full length and original black-and-white.
Critics and viewers found the serial to be relatively dull and unimaginative, not as interesting as Radar Men from the Moon. The use of stock footage from earlier serials is not quite as overwhelming as seen in the earlier or later Cody outings, as greater emphasis is placed on fistfights rather than scenes using the rocket back-pack. Holdren's performance is often stiff and amateurish, especially when compared to the professionalism of the old Republic pros who surround him on screen. Cline describes this serial as just a "quickie."