This is what I’m reading:

Two tribes become stranded on a dying planet (How/ Why?)

This event causes the two ‘tribes’ (races?) to go to war (How/ Why?…the only way i could see this plausibly happening is if one tribe blames the other for becoming stranded on the dying planet..?)

To avert/ stop the war an astrophysicist decides that terraforming(?) the planet will somehow accomplish this..(or is it a different planet? … That’s confusing…because they’d have to leave said dying planet to reach said ‘new’ planet, which means they’re not actually stranded…;) )

Regardless, what’s our hero’s MAIN action — to convince the Enemy that he can terraform a planet, or to terraform the planet? And more to the point, if it’s SECRET, i.e. the Enemy doesn’t even know about it, how could it be used as some kind of peace offering? In Red Mars (a novel, not a film… Yet…) it takes ’em decades, in fact centuries, to terraform Mars… The only way that the author, Kim Stanley Robinson, gets away with it is by the creation of a drug that extends the average human lifespan to 500 years plus…Your guy would have to have some pretty wiz bang method of terraforming planets for me to digest your premise… But who knows?

FWIW, Georgie Boy Lucas’s early drafts of Star Wars are a sprawling mess (not to suggest your screenplay, if written, is…) — if you haven’t read them I’d strongly recommend it — they seem way too focused on the sci-fi elements as opposed the final film’s story, which is simple and well refined, IMO. It can begin and end in getting the story in the longline — and as others have already mentioned, it’s confusing at the moment…

But good luck nonetheless 😉