Help with Blastaway?

I need some help with the game Blastaway. When I start from the control rooms, I always end up getting to a screen with two glass doors on opposite sides of the screen. The problem is I don't have any keys to open these doors and I can't finish the level without a key. I'm pretty sure I've used minimal keys on the previous levels.
What am I missing?

@ktadd

Ah this has happened many times and yes it's frustrating but part of the beauty of the game! Basically you may have picked up all the keys but some where along the road/levels you used an extra key unnecessarily. So next time be very careful and very picky about searching the best paths forward and treat every key like your life depends on it