Kouta is a bit of an enigma. He and Shipon have developed a romantic relationship but there's still a lot about him that is not known. He has an older sister who runs an astrological observatory in Japan. He consistently achieves rank C in every class, without exception, regardless of how easy or hard the subject is. And when he was warned of the possibility of Ayaka attacking Shipon during training, he displayed extraordinary piloting abilities beyond what his ship should have been capable of handling.

Shipon's best friend at the Stellvia foundation. They met on the shuttle up to the station from Earth, and found themselves rooming together and in the same class as well. Though Alisa is nowhere near Shipon in academic or piloting ability, she finds Shipon to be an inspiration to improve herself, and counts herself as Shipon's #1 fan.

A transfer student from the Ultima foundation, Rinna considers Shipon to be her chief rival as well as a good friend. Rinna is a few years younger than Shipon and most of the other students, but because there are few children at Ultima (it being the newest of the foundations, and still incomplete), she had little to do with herself but play with simulators. As a result, she's far better at piloting and zero-G movement than most people years older than her.

One of the older students in Shipon's class, Yayoi had been in Stellvia's training program 2 years before, but left after a flight training accident. She was saved by Machida Ayaka... but it turned out the "accident" was also intentionally caused by Ayaka in the first place.

Recognizing the signs of another "accident" when Ayaka took Shipon out to train alone, she warned Otoyama Kouta of what might be about to happen. Kouta was able to prevent another trajedy.

Despite the attacks on herself and Shipon, Yayoi defended Ayaka when it looked like she might face explusion from Stellvia. Why she was willing to do this has not yet been explained.

One of the Big Four of Stellvia, older students who are at the top of their classes, Ayaka is competative in the extreme. She has something of an inferiority complex which drives her to be the absolute best, and she can't tolerate seeing others better than her.

2 years in the past, when Yayoi was her classmate, she arranged an accident to ensure her own position at the top of the class. Things went a little out of hand, however, and it looked like Yayoi might lose her life, so Ayaka rescued her. Yayoi was hospitalized and traumatized, and left Stellvia for a time. Now with Katase Shima looking like she would surpass Ayaka as well, the same thing almost happened. Had Yayoi not returned to Stellvia and recognized the danger Shipon might be in, Ayaka might have seriously injured or even killed her. Due to Yayoi's defence, Ayaka was not expelled from Stellvia, but was suspended for a time.

Head Teacher of Stellvia's Space Academy. He is also the one who conducted the entrance interview for Shima. He is avuncular and usually takes the optimistic view of events. Richard also encourages his peers to put more trust in the prep students when events put them in critical situations.

A teacher at Stellvia's Space Academy who appears unemotional and calm all the time. Usually, Hutter plays the Devil's Advocate against Richard James' optimism. He is revealed to have a more exotic origin later on in the series.

A teacher at Stellvia's Space Academy who appears to be teaching a science subject. He is particularly obsessed with Astroball, (a game that has some similarities with hockey), which he played in his student days at Stellvia. Passionate and determined, Jinrai becomes more than a mere teacher later on in the series.

Instructor in charge of Pilot Training at Stellvia. She used to be an elite pilot, and spent some time wallowing in despair after losing the "elite" tag. However, she has since recovered from that (after an incident on a space station that was under construction) and chose to become an instructor at Stellvia.

Another of Shipon's classmates, JJ (as he is called) is loud and enthusiastic. He is not very good in his studies nor pilot training and sometimes get needled because of it. Neverthless, he is not one-dimensional and eventually starts dating Akira later on in the series.