Although you just missed Pluto by a hair, I have a good lead for you! You're so close to catching that rascal!
I'm Jocelyn Bell Burnell and I work at Jodrell Bank Observatory and just picked up some funny radio transmissions. When I translated them, I discovered it was Pluto telling some little green men that his ship was damaged by a collison with some rocky debris.
To repair it, he needs to collect some fresh iron.
Where do you think Pluto's space depot is located?