A 1d collision occurs between a rocket ship and an asteroid

Question

Question: A 1d collision occurs between a rocket ship and an asteroid. In the rest frame of the rocket ship, the asteroid is traveling at 0.81c. The asteroid has rest mass 3.4 x 107 kg and the rocket ship has rest mass 5.6 x 10⁸ kg.

Part A: What is the momentum of the asteroid in the ships rest frame O?

Part B: the rocket ship can withstand an impact with energy up to 2x10²³ J. does it survive?

Part C: after the impact, the rocket ship and asteroid can be treated as a single mass. What is the mass' velocity, relative to O, the rocket ships rest frame before the collision?

Please show me step by step or type in formulas used. I am so lost!!