The one you use to get to space is the saucer Excalibur, which has crashed into the mud swamp past the mill. Get the hover board from the attic of the Mill and you can get to it. You will need a new green fuel rod and the coordinates from Mordred's missing journal page (they are X-56 Y-52).
(See related questions)
You do not get or use a bucket on Astro Knights Island.
There is no treasure chest on Astro Knights Island.
There are no bird eggs in astro knights island.
its on the island
How do you talk to the girl in the hay loft at astro knights island?
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.
on astro knights island
With Mordred
Astro Knights
it is in the left
It is on tp of the castle roof in astro knight island