Princess Aurora

Her home world was destroyed by the animoids when she was a girl. Every one on her planet was killed except for her. Before her parents died they put her in a rocket ship allowing her to escape her planet's destruction. She later came into the care of the Emperess and lived in peace for many years, until the hoard of mutants had reached her new home. She was chosen by the Emperess to journey to the Dekos star system to find and stop the source of the mutating energy.


Jesse Dart
He is the most powerful cyborg in the galaxy and is chosen to protect the Princess on her mission. His superhuman physical abilities in combination with his violent impulses and distain for authority make him very difficult to control. Soon after he received his cybernetic enhancements he became bored and seeked new things to amuse him. With his all mighty Astrobat he wreaked havok and destruction across the galaxy. Because of this, the Emperess had him imprisoned in an impenitrable dome on the moon. There he remained until he was later freed by Princess Aurora to join her on her mission to the Dekos star system.


Porkos
He is the second spaceketeer to join Princess Aurora. His name is a play on the name of Porthos from the Three Muskateers and due to the fact that he is quite hefty and is constantly eating. He is also very clumsy and usually ends up upside down in his cockpit. My understanding is that he is meant to be the comic relief aspect of the show. I guess in japan, fat equals funny, but in America , even to a ten year old watching the show, it's just plain stupid.


Arimos
He is the third spaceketeer to join the quest, his name is also taken from the Three Muskateers. He is the most intelligent member of the group and is often the one who solves the problems that they meet on their quest, when these problems require logic and not just might.


The Emperess
The emperess of what, it is never made quite clear. One can assume she is the emperess of her world and perhaps other worlds as well. She is the one who discovered the source of the mutating energy and sends the princess on her quest along with Jesse Dart to aid her. When Jesse becomes to unrully for the Princess to control by mere force of will, the Emperess gives Aurora a special circlet to control him.


Professor Schnitzel
He is the professor responcible for imbuing Jesse with his cybernetic abilities. He chose Jesse among countless applicants for his cybernetic program. He often regrets granting such superhuman abilities to such a disrespectful and undisciplined creature.


The Mutants
Although the mutants behave in evil and destructive ways, they were once peaceful creatures, and only act otherwise because of the evil energy from the Dekos system. The Emperess believes that once the mutating energy is nullified, the creatures will return to their former peaceful selves. It is because of this belief that Jesse and the other Spaceketeers must protect the princess, while at the same time do as little harm as possible to the mutants they encounter.