Just for the record ... I'm not trying to sell any one program. As Heruca has pointed out, Map Forge has an excellent set of tools for sci-fi type maps.
If you use FM8 or FM9 with the Fractal World Explorer (included in the FM8/FM9 package) and download and install the free CSUAC and the free Dundjinni Archives into FM8 or FM9, you'll also have an excellent set of tools for sci-fi type maps.
If you use CC3+ with Cosmographer (a separate ProFantasy add-in that must be purchased) and download and install the free CSUAC 2 and the free Dundjinni Archives into CC3+, you'll also have an excellent set of tools for sci-fi type maps.