Some more background information on this fun series, which today ends the serial.
Taken from wikipedia.
Even though dismissed by modern critics, this was a fun ride for me and many other young kids of our time. Today's cool is tomorrow's pool. Meaning: it ain't as hot as you thought, cause you're old.
Not really. Technology changes. People change.
You can't expect a series made in a few days to stand up to one that is made over months like today's extremely expensive works on TV and in the motion pictures.
I think they did pretty darn well for the time period. And there's a lot of second and third rate movies today that won't stand up to this one.
-- John --
However those numbers are interpreted, in practice the budget for this serial was so tight that no stunt double was used for lead actor George Wallace. His nose was broken by accident while filming an energetic fight scene with actor Clayton Moore. Wallace was also suspended in mid-air, lying on a board with the rocket suit's jacket closed around it, in front of a rear projection screen for the in-studio shot flying sequences. Wallace performed his own stunt flying take-offs by jumping onto a springboard that would send him up and over the camera rig set-up.
This serial is heavily padded with footage first filmed for the earlier King of the Rocket Men, to which this was a pseudo-sequel. A repainted Juggernaut vehicle from the much earlierUndersea Kingdom serial is also reused here as Retik's lunar tank. Radar Men from the Moon shows outer space as brightly lit and the characters walking on the Moon in normal Earth gravity and daylight without pressure suits. His laboratory building is actually a Republic Pictures office building with a prop "Cody Laboratories" sign.
Two different aerodynamic helmets were used with the Commando Cody rocket backpack, with the lighter weight version being used only in the stunt sequences; the single-hinged visors of both helmets were always getting stuck open or closed.
§Release§TheatricalRadar Men from the Moon's official release date is January 9, 1952, although this is actually the date the sixth chapter was made available to U. S. film exchanges.
This was followed by a re-release of Perils of Nyoka, re-titled as Nyoka and the Tigermen, instead of a new serial. Republic's next new serial, Zombies of the Stratosphere, which also used the Cody flying suit and related stock effects footage seen here, followed in the summer.
This serial was re-released on September 30, 1957 between Republic's re-releases of the similar Zorro's Black Whip and Son of Zorro. Previously, the final original Republic serial wasKing of the Carnival released two years earlier in 1955.
§TelevisionRadar Men from the Moon was one of twenty-six Republic serials re-released on television in 1966 as 100 minute TV films under their Century 66 project; the title was changed to Retik the Moon Menace. In 1979 Firesign Theatre used segments of this and other serials in their made-for-TV parody comedy movie, J-Men Forever. 
§Mystery Science Theater 3000In 1989 the serial regained notoriety as the first shorts shown by the cult series Mystery Science Theater 3000. The first eight-and-a-half chapters of this Commando Cody serial were lampooned before their main feature-of-the-week (only half of the ninth installment was shown, with the in-show excuse being "the film broke").
Critical receptionWilliam C. Cline dismisses this serial as just a "quickie" in his 1984 book In the Nick of Time. 
CopyrightBecause of a failure to renew copyright, Radar Men lapsed into the Public Domain in 1979.
Check out my own Rocketman, whose adventures are totally different from the movie serials or the more recent rocketmen. Taken from a movie idea I pitched to major motion picture studios back when, I have modernized him further and taken him in two different directions...today and an alternate future where the Nazis have won the Second World War.