... oh and to contribute somewhat to the OP..

I believe if a clearly definable idea has been published then it has preceedence over subsequent missions or intended missions ofc.

However.... its like that old argument I used to hear... "Battlestar Galactica/Stargate Universe is such a rip-off of voyager in how they are alone and searching for home etc" - oh come on, you can't patent an IDEA - even Shakespeare got his influence (albeit plagiarised *cough*) from many of the Greek dramas of old...

Very good point nynik!