The Hot Shot, All-American Earthling, de facto leader of the kids. He was skilled at gymnastics and martial arts.
Played by Walter Jones.
- Ace Pilot
- Badass Normal: As the only bog-standard human among the kids, he's also the only one without any "powers", though his martial arts prowess helps make up for it.
- Belligerent Sexual Tension: His interactions with Catalina and later Suzee usually come off as this.
- Bullying a Dragon: Loves to torment Radu, who comes from a super strong species that could easily turn him into paste. Fortunately for him, Radu is too much of a Nice Guy to ever actually do so.
- Fantastic Racism: Against Radu, since his father was killed in the war against the Andromedans.
- Hot-Blooded: "Harlan Band leaps before he looks."
- Humans Are Leaders: Immediately assumes this position among his alien classmates without consulting them first, though none of them seems to object really. In the episode where he and Radu swap species (long story), Radu is the one who immediately assumes command, and again, no one really objects.
- Jerkass: Sometimes it's hard to believe the other kids even like him.
- The Leader: In his own mind, and the other kids do usually reluctantly treat him as their unofficial leader. Sometimes he lives up to the concept.
- Leeroy Jenkins: He leaves the plans to Catilina or Suze. He'd rather jump in.
- Small Name, Big Ego: "Harlan Band thinks he knows it all."
- Team Normal: Again, the only human child on The Team.
An Insufferable Genius with rainbow hair from Titan, Saturn's largest moon. Has the ability to produce supersonic screams. She has a friend named Suzee, who exists in another dimension. The other crew members think she doesn't exist and think she is just an "imaginary friend," at least at first.
Played by Jewel Staite.
- Cloudcuckoolander: "Catalina is talking to the wall."Catalina: She's invisible!
- Deadpan Snarker
- Insufferable Genius
- Make Me Wanna Shout
- Multicolored Hair
- The Smart Girl
- Teen Genius
- Tsundere: Type B, towards Harlan.
- Wrench Wench
A young man from Andromeda who possesses Super Strength (while being, in a reversion of the associated trope, short, slight, and not in the least bit imposing or aggressive) and super hearing. Because of their abilities, Andromedans were enslaved by an evil alien race called the Spung, the show's version of Star Trek's Klingons. Radu faces prejudice from Harlan early in the series, due to the fact that Harlan's father was killed by Andromedans during a war.
Played by Kristian Ayre.
- Beware the Nice Ones: Generally very kind, shy, and gentle, but he can rip you apart if you get him angry enough.
- The Big Guy
- Interspecies Romance / Star-Crossed Lovers: With Elmira, though it never gets to get farther than a kiss.
- The Lancer
- Mr. Fanservice: Sweet and shy despite his Proud Warrior Race, and with enough guilt and self-effacing tendencies to make him a massive woobie. The episode where he turns into a human is very popular.
- Nice Guy: Very nice.Harlan: Did you know that when you enter a room, the hair on the back of my neck stands up?Radu: Yes. I hear it.Harlan: That's gotta bug you right?Radu: Well, um, I'm not thrilled about it, but...
- Pint-Sized Powerhouse: Though he's not a midget, just shorter than you'd expect (the actor is only 5'5", to boot). Word of God is that the Andromedans have extremely dense molecular structures, which is why they're so strong, but also makes them short.
- Star-Crossed Lovers: With Elmira, which is awkward because her race used to keep his race as slaves. He also gets Ship Tease moments with Suzee in season two.
- Super Senses: His hearing, thanks to spiral-shaped ears.
- Super Strength: "Radu's really super strong."
He hails from Uranus, and has an antenna which creates electricity and a high metabolism. Really hates it when people make jokes about his home planet. Perpetually depressed, but in a Played for Laughs way.
Played by Rahi Azizi.
- Deadpan Snarker: If there's a sardonic comment to make on a situation, he will be the one making it.Harlan: I'm tired of running from the Spung! This time they're going to know they've been in a fight!Bova: Oh, yeah, they'll be scraping us off their windshields saying, "Some fight, huh?"
- The Eeyore: "Bova acts likes nothing's funny."
- Kid-Appeal Character
- Lightning Can Do Anything
- Odd Friendship: With Rosie. Tips over into Ship Tease occasionally (like when she mistakenly assumes he's giving her a shoulder rub at one point).
- Personality Powers: He's cloudy and creates lightning.
- Planet of Hats: Uranians are a pretty pessimistic bunch, both from being so far from the sun and from people making fun of their planet's name.
- Shock and Awe
Cheerful young girl from Mercury who is hairless and has hot pink skin. She can create heat and always has a "sunny" attitude about everything.
Played by Paige Christina.
- Bald Women
- Beware the Nice Ones: Even more so than Radu. She's the sweetest, nicest, cheeriest little thing you will ever meet, but she does come from a species that can scorch anything just with a touch...
- Blessed with Suck: In one of the show's promos, Rosie notes that her optimism is mainly because she doesn't have much of a choice. If she even so much as thinks about getting upset, her body overheats.
- The Chick
- The Cutie
- Cheerful Child: "Rosie's cheery, bright, and sunny."
- Genki Girl
- Playing with Fire
- Meaningful Name: "Rosie" ties into the reddish-pink colour of roses, complimenting her pink skin.
- The Medic: Even by way of Heal It with Fire occasionally.
- My Blood Runs Hot
- Nice Girl
- Odd Friendship: With Bova.
- Personality Powers: She's sunny and creates heat/fire.
- Pink Is Feminine: Aside from her skin, her fire is pink too.
- Planet of Hats: All Mercurians are sunny and optimistic, with a huge smile constantly plastered on their faces. Rosie is downright placid compared to her parents.
- The Pollyanna
The resident robot and ship's avatar. She's a little screwed up, thanks to Harlan stepping on and cracking her jewel. It's not clear how much of her personality was like that before the jewel cracking, though.
Played by Anik Matern.
Theresa James "T. J." Davenport
The kids' teacher at the Academy, who accidentally gets stuck on board the ship after having to go search for them when they sneak out of her class onto the Christa.
Played by Cary Lawrence.
- Belligerent Sexual Tension: With Commander Goddard.
- British Stuffiness
- The Comically Serious
- Crouching Moron, Hidden Badass: On the very very rare occasions she avoids fainting or panicking, she can be surprisingly effective.
- Fainting: Near constantly.
- Gender-Blender Name: ..."James"?
- Stern Teacher
- Stiff Upper Lip: She... tries to project this image, but generally fails spectacularly.
- Team Mom: She tries to be this to the kids, but they usually don't buy it.
Commander Seth Goddard
The kids' second teacher, an officer and veteran of the Spung War that was busted in rank after an incident with a space pirate.
Played by Paul Boretski.
- Badass Teacher
- Belligerent Sexual Tension: With Miss Davenport.
- Catchphrase: "Space hates... <x>!"
- Demoted to Extra: Suffers an accident that leaves him in a healing coma for most of the second season as part of Nickelodeon wanting to make the show Younger and Hipper.
- "Metaphor" Is My Middle Name: According to Word of God, his middle name literally is "Danger".
- Reasonable Authority Figure: He's more willing to put up with the kids' antics than Miss Davenport is, and more palatable to them in how he gets them to behave. Probably because he's essentially a rebel himself, and also treats them more like his officers than like kids.
- Reassigned to Antarctica: After the Noodle Incident with said space pirate he was busted in rank and sent to the Academy to teach.
- Skunk Stripe: Two grey ones, on both temples.
- Team Dad: Succeeds at this better than Miss Davenport does at being Team Mom.
A young Spung Oracle girl who runs away from her people to escape their control over their women, and ends up meeting and helping the Christa's crew. Was going to eventually become a main character, but the network kiboshed it and shoved in Suzee instead.
Played by Katie Emme McIninch.
- Cute Monster Girl / Green-Skinned Space Babe
- Defector from Decadence
- Interspecies Romance / Star-Crossed Lovers: With Radu, eventually.
- Mad Scientist's Beautiful Daughter
- My Species Doth Protest Too Much
- Non-Mammalian Mammaries: She's a lizard woman with curly hair and breasts. Don't ask too many questions.
- Rebellious Princess
- Star-Crossed Lovers: With Radu, which is awkward because her people used to keep his people as slaves.
- Waif Prophet
A Spung commander and space pirate, who first encounters the Christa while trying to retrieve the escaped Elmira, and eventually develops into one of the series' major villains.
Played by George Takei.
- Actor Allusion: When Harlan informs him that the hull of the Christa is made from a material that, if the ship is destroyed, will destroy Shank's own ship from the resulting explosion, Shank laughs off the "obvious bluff". He would know; he was there when the guy who first thought it up came up with it in the first place.
- Big Bad
- Large Ham: Not surprising, considering who plays him.
- Third-Person Person
Catalina's "imaginary" friend, who turns out to really be an alien girl living in a different dimension. If you took all of Catalina's personality traits and set them on HIGH, you'd get Suzee.
Played by Rebecca Herbst.