The first Space Mouse was a comic book character published from 1953 to around 1956 by Avon Publications. "Space Mouse" was also the name of a 1959 Universal Studios cartoon featuring two mice and a cat named Hickory, Dickory, and Doc. A second Space Mouse character was published by Dell Comics (and later by Gold Key Comics) from 1960 to around 1965.
In 1959, Western Publishing Company held the license to produce comics based on the properties of Walter Lantz, such as Woody Woodpecker, Chilly Willy, and Andy Panda. Western realized that they were paying a lot of money to Lantz for the rights to his characters, but they weren't getting as many different titles out of the arrangement as they would have liked. Western's execs instructed their senior editor, Chase Craig, to launch another comic book based on a Lantz property. He looked over the available characters and decided that none of them could sustain their own series
Chase then spotted a press release from Walter Lantz Productions that indicated they were producing a cartoon short entitled "Space Mouse". He imagined a Buck Rogers style strip, starring a mouse in a space suit, and felt it would make a great comic. Chase called Lantz's office and had them send over a copy of the "Space Mouse" storyboard. It turned out that the cartoon was not what Chase had been expecting at all. It was merely the title of the first cartoon in an intended series, starring Earth-bound characters named Hickory, Dickory, and Doc. Believing that a sci-fi mouse was still a great idea, Chase got together with his writers and artists and began working on the comic book he had in mind.
At that time, Dell Publishing paid Western to prepare and print the contents of their Dell Comics line, while Dell controlled the distribution. Throughout the years of their business arrangement, almost all of their comics featured licensed material. However, a small battle was going on between the two companies over the ownership of properties appearing in the non-licensed comics. Dell claimed to own them because they were financing the books. Western felt that these were creations of their employees, and thus belonged to them.
As a result of these squabbles, there were periods when Western decided they would not create any new characters, and Space Mouse was conceived during one of those periods. Not wanting to find himself in the middle of an ownership fight, Chase decided to simply turn the concept over to Walter Lantz. After a few pages of the new strip were completed, Chase took them over to Lantz's office and asked for permission to publish the comic as a Lantz property. Lantz, who would own the copyright, of course agreed.
from Four Color #1244, Nov. 1961. Art by John Carey