far-trader
SOC-14 10K
Yeah, IIRC the primary hull in TOS was detachable for emergency use only - i.e., it was a one time deal.
And it got used in a novelization iirc.
I was kind of surprised it wasn't used in Wrath of Khan (? I think that's the one they just let it burn up in atmo wasn't it?).
One of the tech manuals describes it as a "lifeboat" measure. No thrusters, just a dead stick landing on a long flat place so the crew can be quickly evacuated to a presumably handy type M world to await rescue.