I'm honestly still new to the whole Twitter thing in general, but I'm trying out a few things.
1) If Lara trusted the Coalition, she’d work for them as a pilot flying the void between the worlds. She’d know what to think when they tell her a captain went rogue + killed the other pilots. But if Lara doesn’t fight with them, the captain might end the worlds.
2) Lara pilots her airship through the void between the worlds, scavenges in ancient ruins for lost artifacts, and always sticks her neck out for her tight-knit crew. Now she has to chase a military renegade through the void to prevent society’s destruction.
3) Lara Kavarin flies her ship through the void between the worlds, seeking lost treasures. Amerlaine Silver wants to unleash the horrors of the void to destroy society. Outmatched, Lara must stop her, or else the worlds will become a living nightmare.
Sounds like a space adventure, for sure! I agree with Michael that the premise and the stakes aren't really clear from any of these pitches. Really focus on the character and the conflict. We want a god understanding of who the main character is, the conflict she faces and what the stakes are.
I think your third pitch is definitely the strongest so far. I'm going to mess with a bit just to see what happens:
Treasure hunter Lara Kavarin flies her ship through the void between worlds. When she stumbles on (Government agent/rouge scientist, who is Amerlaine) Amerlaine Silver's plan to unleash the horrors of the void, Lara must stop her before her crew is (captured/murdered/turned into monsters) and the worlds are destroyed.
One quick note, I found the word "the" before worlds to be a little distracting. It seemed to interrupt the flow. If it is a title The Worlds, I would capitalize it.
Good luck!