NASA: Engineering Design Challenges: Spacecraft Structures Educator Guide : 9781288297245 : 1288297246 : 13 Nov 2012 : The structural elements that hold together an aerospace vehicle must be strong and as lightweight as possible to minimize the fuel needed to reach orbit. NASA engineers continually strive to develop new materials and methods of structural design. In this challenge, students will undertake the problem of designing a strong but lightweight thrust structure that can withstand the launch of a bottle rocket by means of a wooden lever. By using simple materials such as craft sticks, cardboard, and a hot-melt glue, students strive to make their structure lighter while maintaining its strength. The goal is to construct a launcher that can withstand the force of repeatedly launching a one-kilogram bottle of water one meter into the air. The scientific focus is on understanding forces, structures and energy transfer.