Rocket Catcher Challenge for Grades K-5

Companies like SpaceX and Blue Origin are trying to make spaceflight cheaper by designing reusable rocket boosters. Instead of crashing or burning up in the atmosphere, these rockets must land gently and without damage so they can be reused. This means that engineers must carefully steer the rockets back to Earth while keeping them upright. Some rockets land upright on the ground (Figure 1), and some are even caught by towers that grab them in midair (as shown in the video)!

Image Credit: Blue Origin

Figure 1. The booster from Blue Origin's New Shepard NS-25 flight after landing in the desert.

https://www.youtube.com/watch?v=nVNIoQUcFI4

This engineering challenge is inspired by real-world reusable rocket landings like those shown above. Your students' goal is to build a device that can "catch" a falling rocket (a paper or cardboard tube) so it lands vertically. They can also modify the rocket and add features like fins, a nose cone, hooks, or other attachments. The farther they can drop their rockets and successfully catch them, the higher their scores. They can only use certain simple materials, like paper and tape, and each material has a "cost." Figures 2 and 3 show a few example designs. These designs are just ideas to help your students get started. They can come up with their own ideas and build something totally different!

Image Credit: Ben Finio / Science Buddies

Figure 2. Example devices designed to catch a falling rocket (shown alongside the rockets).

Image Credit: Ben Finio / Science Buddies

Figure 3. Example devices after the rockets have landed. 

There are many physics and engineering principles you can connect to this project. 

• This project uses the engineering design process, which includes steps like doing background research, defining criteria, and brainstorming before you start building anything. Iteration, or repeating some steps more than once, is a normal part of the engineering design process. Your students' devices might not work well on the first try, and that is OK! They can test their designs, learn from their mistakes and failures, and use that information to improve their designs.
• A falling rocket has both kinetic and potential energy. That energy does not disappear when the rocket hits the device. According to conservation of energy, it needs to go somewhere! It can transform into other forms, like acoustic energy (sound), thermal energy (heat), or elastic energy (bending, stretching, or compressing materials). 
• A falling rocket experiences aerodynamic forces. Drag acts opposite the direction of motion, and lift acts perpendicular to the direction of motion. This may be confusing at first because we normally think of lift as acting up when referring to something like a flying airplane. But in this case, since the rocket is falling down, drag acts upward (opposite the direction of motion), and lift acts sideways! A rocket's shape, including any attachments like a nose cone or fins, will influence the aerodynamic forces on it and its aerodynamic stability (whether it tends to fly straight or tumble as it falls).
• Different materials have different material properties, like density, stiffness, and strength. Different materials that rub against each other also have different coefficients of friction. Your students need to take these material properties into account when building their devices. A device that is too weak may break when the rocket crashes into it. A design that is too springy may cause the rocket to bounce back out after landing.