In the original Japanese version of the series, Fireball is the lead character. However, in the American version Saber Rider is the lead character.
In the original Japanese version, Saber Rider is from England, Fireball is from Japan, Colt is from the United States, and April is from France. In the U.S. version, Saber Rider is still from England, but the other three are all American. However, you can still see their respective flags on their spacesuits.
The planet Yuma is named for Yuma, Arizona, which was a famous town in the days of the Old West in the United States.