What if in ST Generations The saucer was not destroyed when the core breached? Would Starfleet have replaced the Stardrive?
Doubtful. For the resources needed to build a new one and make repairs to the saucer it would be just as cost effective to commission an entirely new ship.
Yes, replace the stardrive section with a big triangular-shaped hull that's about twice as big as the saucer, and has really long nacelles. And give it an advanced drive that can instantly transport the ship to just about any point in the multiverse. Kor
He said if the saucer hadn't been destroyed i.e. no crash. Repairing a bit of battle damage to the saucer definitely would have been more cost effective than building a new one. So yeah, had the saucer not been destroyed it's very likely they would have used it with a new stardrive.
The saucer hadn't crashed but still would've been hit with the full force of the matter/antimatter explosion from the warp core which probably wouldn't have been good for the structural integrity. The ship also took multiple hull shredding hits, in TUC the Enterprise-A only had one hull breach but was decommissioned following that battle.
The saucer wasn't really damaged all that badly. It just crashed. As opposed to the stardrive section, which was blown to bits. In-universe, it would have made more sense to just salvage the saucer (which they'd have to do anyway to get it off the planet), repair it, and reattach it to a new stardrive section that was undoubtedly being assembled at the time, as opposed to designing and building an entirely new ship.
If the saucer went to to a junk yard it may have been used to replace another galaxy class saucer that got trashed in the dominion war. We saw a bunch of Galaxies were in the war, would seem to make sense they they could uses the Ent-d's old saucer with repairs then building a new one since they need as many ships as they could get ASAP in the war.
I would think that if anything, the saucer would gave gone into the Fleet Museum. This is the saucer section of the U.S.S. Enterprise NCC-1701-D, the Federation's flagship, after all. The ship and her name have history.
The saucer would have suffer massive structural damage during the crash which would have been compounded by the landing - the saucer wasn't designed to support it's own weight so would have crushed the lower decks just be resting on the surface of Veridian III. Not to mention the massive systems damage from the impact and power surges. Given the stresses of spaceflight Starfleet wouldn't want to risk a saucer section that had suffered so much structural damage. They would have savaged what they could and scrapped the rest (assuming they didn't just destroy the saucer where it landed).
In the novel “Rogue Saucer”, which is set in TNG’s with season, just before “Generations”, Starfleet had just had the saucer undergo major refit and upgrades—-so much was done that Starfleet had the E-D flying around with a prototype saucer for a while, testing it while the main saucer was undergoing its refit. (It explains why the bridge looked so different from “All Good Things” to “Generations” and the change for Stellar Cartography.). So if the saucer only needed minor repairs, they could’ve just repaired it.
From the book jacket it was an experimental saucer designed to survive crash landings. I don’t recall if it was fully finished or just at the point where they could do the test to see if it could crash and then blast back into orbit.
That I do remember - it was pretty much unfinished beyond the basics needed for operations so if things went wrong they didn't write-off a full fitted out saucer section.
But the saucer was specifically designed as a lifeboat that was meant to land on a planet in an emergency and keep its structural integrity intact. https://i.stack.imgur.com/X93fW.png So I'm sure the saucer was salvageable.
Structuraly intact to act as life boat doesn't mean able to be salvaged and returned to active service. Doubly so when you consider the battle damage and the uncontrolled landing. The scenario from the Technical Manual shows a nice controlled approach looping back to decelerate and the SIF set to maxium. The Enterprise saucer had pretty much no helm control and landing wasn't their intend - it was the result of being blown off course by the stardrive section exploding.
Also I feel "landing on a planet" isn't the same as "crashing on a planet"? Like you can land an airplane or you can crash it, but only in one case you can reuse it right? Maybe their saucer could've landed safely and taken off again, but in Generations you see it totally go out of control and tear itself apart crashing through that planet.
Perhaps the saucer could have been salvaged and used for other things, like cadet training missions. Or it could be turned over to Starfleet colony support services and used that way. They could use it to establish a new colony and then the saucer could be dismantled and used to build the first buildings (we've seen this happen before).
Heck, if it's a saucer, why not put it on a planet inhabited by giants? They can place their tea cups on top of it.