Astro, A.K.A. Experiment 552, is an illegal genetic experiment created by Jumba Jookiba. He is designed to suck the leaders of planets into its air bubbles and then go into an orbit around the planet. His one true place is orbiting the planet, fixing broken satellites, and now is as a spectacular amusement park ride where he orbited Earth, showing birds-eye views of Earth to amazed tourists.
Experiment 552 was the 552nd genetic experiment created by Jumba with Hämsterviel's funding. He was originally designed to suck the leaders of planets into its air bubbles and then go into an orbit around the planet. He then detached the air bubbles and left them drifting until someone found them. If those people are found, 552 would repeat the process on them. In this way, planets would only have their leaders for a very short time. Without any leadership, entire civilizations would collapse! By now, Jumba was getting ambitious. For Experiment 552, he wanted to cause mass panic out in space. So he experimented with asteroid dust and used it to create 552.
552 and the other first 624 experiments were deactivated and smuggled to Earth by Jumba during his mission to capture Experiment 626.
All of the experiment pods were released and scattered across the island of Kauai.
At an unknown point, 552 was activated, captured and named Astro.
In Astro's fake episode, Jumba discovers that 552 was activated almost at once as his pod fell towards Kauai, and that he was gotten into orbit around the Earth by sneaking a lift on the underside of Jumba’s ship during the events of The Asteroid. He realises that a Galactic Council representative is coming to check on the welfare of Stitch’s ohana and that 552 must be stopped before he tries to disable the ship. Once he gets all the experiments of the 5-Series to the ground, it was an easy capture; 552 can move quickly in the cold reaches of space, but his rock-like body makes him slower on Earth. Experiment 552 was then christened Astro.
Astro is a taller, brown, legless Stitch-like experiment with smaller ears with two long pointed horns, a ring with 15 stubs pointing out that grow into large arms ten yards long with transparent air bubbles at the end of them.
His entire body is encased in a living asteroid, into which he can fold away his head, arms and legs giving him the deceptive appearance of a plain asteroid. He sneaks up on ships this way, then lands on them and unfolds to tear apart essential mechanics in the ship.