Check the wiki, search for 'assignment chains' and you'll get a list of all the chains. Drill down into the specific chain and mission, and it has a map of the sectors where that mission will occur. No sense looking for that mission in, say Alpha Centauri block.
(OK, that's a guess from memory. It *may* in fact be available in AlCent space, but I don't know without looking, and for some reason the wiki tends to make Firefox on my computer do bad things, so I won't look for you.)