Thank you!
It's a modeled object, done in an old program called Truespace. I've looked at the "save as" options, and I don't see .obj listed. Can the program you're using open .cob files?
The model is still a "work in progress" (both versions) as I still need to figure out / finalize the saucer details. I've managed to not really show much of the saucer in any pics of the ship for that reason. Once that's done, I'll be more than happy to send you a copy.
Funny enough, I DO own a copy of TrueSpace! I've used it to create few Doctor Who based freebies (a Davros chair and the 4th Doctor's console) with the Poser community. I think the last couple of releases (version 6 and newer) included what was a third party "plug-in" to both import and export .OBJ files. But since I have the program itself, there's no need to convert and export.
Certainly, finalize your design. I just love that "Japanese" version! I can easily imagine it suspended by wires, streaking across that royal blue star studded backdrop, chemical rockets spewing flame that arcs upward as well as the spent vapors and smoke, all the while the Navy anthem playing like one hears in nearly every Godzilla flick.