Eu diria que Nebula 9 foi um aceno para Firefly , mas havia muitas referências a outros programas de ficção científica também.
De Le Geek :
Firefly references:
Nebula 9's Captain is called Max Reynard, in Firefly the name was Mal Reynolds
Lt. Chloe in Nebula 9, Zoe in Firefly
Creavers in Nebula 9, Reavers in Firefly
Nebula 9 was cancelled "over a decade ago, and only had 12 episodes at that"
Castle says "Shiny" a common phrase in Firefly for 'good' or 'cool'
Castle also says: "I'm a fan of good sci-fi. StarTrek, Battlestar, that Joss Whedon show,..."
referências Star Trek :
Jonathan Frakes (William T. Riker) not only directed the episodes, he also has a cameo.
[Source]
Armin Shimerman (Quark) also made an appearance
[Source]
Castle is doing a Captain Kirk impersonation
Castle is doing a Captain Picard impersonation
(Clique no link 'Le Geek' para mais referências a outros programas de ficção científica, filmes e cultura de fãs)