This was a winter birthday, which meant everything had to work indoors in a not very big living room. Space turned out to be the perfect answer: dark cloth, silver, and one big cardboard box.
The rocket took me two evenings and it was worth every minute. Children queued to sit inside it. It stayed in our hallway for a month afterwards.
Everything else was paper lanterns and star confetti, which cost almost nothing and made the room feel completely transformed.
Tip
Start the rocket a week before, not the night before — cardboard painting needs drying time. Supermarkets will usually give you a big box for free if you ask at the desk. Keep the room dim: it hides every imperfection and doubles the atmosphere.