When a top-secret anti-gravitational experiment goes awry, a whistle blowing scientist is pressed back into service by the military. She must then expose a military contractor cover-up while finding a way to halt the effects of the riff before it goes planet-wide.

Dpg's suggestion is good except it would be better to make the scientist more proactive, like in your original logline.

When a secret anti-gravitational experiment goes awry, a rogue scientist must be recruited to contain the damage before it destroys the planet.

When a secret anti-gravitational experiment goes awry, a rogue scientist must be recruited to contain the damage before it destroys the planet.