Alice is like a magic potion that helps rockets go zoom really fast up into outer space! Rockets need fuel to blast off into space, and Alice is a special kind of fuel called a propellant. It's made up of two different parts that when mixed together, make a big boom that pushes the rocket up and away from Earth.
Think of it like a big balloon that you blow up and then let go of - the air rushing out pushes the balloon up high into the sky. Alice works kind of like that, except instead of air, it's a super powerful mix of chemicals that make the rocket fly. Without Alice, rockets would just stay stuck on the ground and never get to explore the cool things in space!