If you do space science, it's difficult to imagine its application beyond research-related fields (though I'm no expert, and as somebody who can defend an English degree, there are people who can talk up the qualities of that degree I'm sure).
However, speaking as the person who edits a ton of science grants, it would be badass as fuck to get your masters/Ph.D in a space science.
Ironically enough, however, I don't imagine mortuary science being a dead practice, or one with little demand. (Again, I have no basis for that claim, other than the fact that everybody dies.)