on the castle
You do not get or use a bucket on Astro Knights Island.
This means you have already completed the Arturus part of Astro Knights Island. Your spaceship should be parked on top of the castle if you return to the planet.
its on the island
There is no treasure chest on Astro Knights Island.
Big Nate Island was released in February, 2009, and followed by Astro Knights Island in June, 2009.The island after Big Nate island was Astro Knights island in June, 2009.
you beat the island
It's on the castle, climb it and you'll find the rocket.
Yes. (But you have already picked it up by now.)
on astro knights island
The following island was island nine, Astro Knights Island, in June, 2009
On every island you have to be the one to save whatever needs saving. That includes the kingdom in Astro Knights Island.
Once you have built a new spaceship on Astro Knights Island, it will park on top of the castle whenever you leave the island.