I used to be able to stop the biggest asteroids in a single well timed blast. I think making the progress bar faster and so harder to max out, made this less common.
Turning them 180° is only effective while you have time, at the start. Small (ok, maximal) nudges to steer them off course was the intention.
I would offer powerups for this if I had the time. If I simply scaled the explosive charge across the board the smaller asteroids' speeds would be harder to modulate, and fly off too fast, potentially snowballing into more high speed fragments if/when they collide.
The tools are not enough to manage the problem. It is a survival game at the moment, I can last 500s, or 400s reliably, which is more than I imagined anybody would be willing to put in.
Maybe the asteroids could be uniformly smaller, they are 25 - 36 x 1,000,000 kg at launch. The mitosis was supposed to be "indefinite" so I ran with this.
Thanks for reviewing.