The Stellosphere is a spaceship and serves as a home to the Callisto family. Crewed by the Callisto family and commanded by Miles' mother, Captain Phoebe Callisto, the Stellosphere's mission is to explore and connect the universe for the Tomorrowland Transit Authority.
Stella is the ship's main computer who assists and watches over the Callisto family throughout their daily lives aboard the ship. Her mainframe is located in the main power access room. From there she can operate, as well fly the Stellosphere entirely alone. But her primary duty is assistance and security. Throughout the ship, the Stellosphere is fitted with Voice Modulators which allows Stella to speak to anyone from any part of the ship. Set on the walls, her modulators are black wide monitors that display two white dots and a straight line that flashes vertical bars each time she makes a sound.
Despite being a computer that follows orders, Stella is capable of thinking for herself and offer suggestions without being asked. She is shown to have a calm, friendly, nurturing personality and overtime the Callistos have come to see Stella as a member of the family.
- Galactech Mode: When the Stellosphere suffered severe damage after passing through a portal that led to the Builder's homeworld, the ship was upgraded with a powerful energy globe known as Galactech, making the Stellosphere the fastest and most advanced starship in the TTA. When in Galactech mode, the Stellosphere becomes more faster and stronger than it usually is. It even changes appearance when in this state, along with everything else on board, like the Callisto's spacesuits. The Galactech can also self repair any damage to the Stellosphere, leaving it looking like new.
- Galactech Shields: When in very intense conditions, the Galactech shields are strong enough to withstand any harsh environments the Stellosphere encounters, such as the intense weather conditions of a Hot Jupiter. Once activated, the ship becomes covered from nose to tail in holographic armor.