I read Howl's Moving Castle before I saw the film adaptation of it, and while I do like the film, I prefer the book. It's difficult to tell just from the description you've given how similar Howl is to your character, but I will say that it's impossible to create a completely unique character, so as long as your character has some things that set him apart from Howl (and I can already see from the astronaut point that he has) you should be fine
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SOPHIE: BtN's resident whimsical insomniac fairytale-junkie!
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“
Hope is the thing with feathers"
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Emily Dickinson
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