Astronautics Activity Badge - Option two
Build a scale model of or about the topic, either from a commercial kit, or from plans available from the Internet or model clubs and shops.
Rocket kits - something like http://www.modelrockets.co.uk/shop/schoolscoutcadet-packs/enhanced-20-4fnc-twenty-ez2build-rockets-p-3284.html
Kits come complete with everything required to build rockets.
Don't forget to ensure you have a launcher or two