I lock a door and cross the sky, I shoot from start, I suddenly fly. Catch me with lightning if you can. What am I?

Capsules of time, I have helped safely stow. I make space with my head for new flowers to grow. I can hide or uncover what lies down below. The more you heave-ho, the deeper I go.

Push my button and I'm ready for battle. I'll bleed all over the battlefield for you, or at least till you are satisfied.

I can break the sound barrier, not to brag. If you want to try, just grab a wet rag.

Forwards I'm heavy, backwards I'm not. Whether steel or a feather, it matters not.