You have to beat all the 3 planets after you get the new spaceship from the Pewter Moon, then go to the asteroid city, and beat Mordred. You will automatically go back to the castle back at Arturus.
Fix the saucer, beat the three planets, and defeat the Binary Bard.
When you beat a planet (jungle, fire, ice), the space knight there goes with you. Sir Peleas is outside the door to the lair of the Fire Beast (robot dragon) and gives you the Ice Arrow to use against it.
Find the mystical weapon and the space knight, and beat the boss monster of each planet. On the jungle planet, you need to find the Laser Lance. On the other two planets, the knights provide the weapons. (see related questions)
if you don't talk to the princess just press on the door but if already talked to her you have to look up a walkthrough
Unless you want to dress up like Shark Boy on Shark Tooth Island, that's not how to beat the Space Sharks. (see related question)
beat the beast and let the knight join your journey
all you get is the island medallion and 100 credits
The 9th Island was Astro Knights island released in 2009. (see the related question)
The island with Poptropica's space program is Lunar Colony Island. (see related question) Unlike the earlier Astro Knights Island, this island uses more-or-less the real Moon, but with physics errors such as no gravity in one area.
well just beat the stupid thing ingnore her baby birdies
Wimpy Wonderland Red Dragon Island Counterfeit Island Mythology Island Astro Knights Skullduggery
well just beat the stupid thing ingnore her baby birdies