Together with 4 other students, I set off to build a rocket with the goal of launching an egg to 1 km and having it return safely. Quickly, we introduced an extra challenge: there would be no parachute on board, but only a helicopter-style rotor to slow the rocket down. 

For all of us, this was the first rocket we designed. Therefore, a lot of mistakes were made, and the final rocket was far from stiff enough to survive a launch.