NASA STEM ACTIVITY

ON TARGET

The Artemis 3 mission will land the first woman and next 

man on the south pole of the Moon. Our orbiting platform, 

Gateway, will allow us to land in almost any location we 

choose using an ascent/descent vehicle – the human landing 

system. It is important that it lands in just the right spot for 

the safety of the astronauts and the success of the mission. 

On Target is an engineering design activity that gives you the 

opportunity to design your own model to land on a target. 

National Aeronautics and

 Space Administration

CHALLENGE

Modify a paper cup so it can zip down a line and drop a marble onto a target. Follow the engineering design process to: 

1. Modify a cup to carry a marble down a zip line.

2. Attach a string to tip the cup and release the marble.

3. Test the cup by sliding it down the zip line, releasing the marble and trying to hit a target on the floor. 

4. Improve your system based on testing results.

MATERIALS

• 9 feet (3m) of smooth line • Masking tape • Scissors

(e.g., fishing line or kite string) • A Paper clip • Target drawn on a piece of 

• Index card • 1 medium-sized paper cup paper

• A marble

BRAINSTORM AND DESIGN

Brainstorm and decide how you want to carry and launch the marble. Ask yourself: 

• How will you modify the cup so it can carry a marble down a zip line and also drop it onto a target?

• How will you remotely release the marble from the cup?

• When do you need to launch the marble so that it will hit the target?

CHALLENGE YOURSELF

How would you modify your cup? Be creative with 

what you have around the house.

Where is the best place for the marble? 

If you don’t have a cup, what else can you use? 

How about a paper tissue roll?

Take a look at the drawing for some inspiration and 

try something new! 

www.nasa.gov
BUILD

1. Set up a zip line. Tie 6 feet (1.8 m) 

of the smooth line to two objects 

(e.g., two chairs, or a table and 

chair). Make sure it is stretched 

tight and that one end is about 20 

inches (50 cm) below the other.

2. Figure out how to modify the cup 

to carry the marble down the zip 

line. Will it travel inside the cup? 

Outside the cup on a platform? 

Underneath? It’s up to you! 

3. Add a remote release. Decide 

how you will tip the cup at just the 

right moment to launch the marble 

toward the target.

4. Clip the cup to the zip line. Modify 

and decide how to hook the cup 

onto the zip line so it slides easily.

TEST, EVALUATE, AND REDESIGN 

Ready for a test run? 

Place the target near the end of the zip line. Send down the 

cup and try to hit the target with the marble, using the remote 

release. How close did you get? See a way to improve your 

design? Engineers improve their designs by testing them. 

The steps they follow are called the design process.

WHAT YOU LEARNED 

•	 Newton’s First Law: As it travels down the zip 

line, the marble builds up a forward speed. Once 

launched, it will keep going at that speed until a force 

acts on it, such as hitting the ground.

•	 Acceleration: Due to Earth’s gravitational pull, the 

marble’s speed increases as it falls.

•	 Vectors: The marble’s motion has both a horizontal 

and a vertical component, and these motions can be 

represented in a vector diagram.

•	 Trajectory: When an object that’s already moving 

horizontally is dropped (like a marble dropped from 

a cup moving down a zip line), it travels in a curved 

path, called a trajectory.

•	 Potential and kinetic energy: The marble’s stored 

(potential) energy changes to motion (kinetic) energy 

as it falls. 

•	 Measurement: You measure to make the zip line. 

You also measure the height from which their marble 

is dropped and how far it lands from the target.

IMPROVE YOUR IDEA 

For example, if your cup:

•	 Moves slowly: Check that the zip line 

is steep enough. Also, make sure the 

cup slides freely.

•	 Can’t keep the marble in: Roll up 

a small amount of tape to keep the 

marble from falling out accidentally. 

Also, adjust the tilt of the cup so it 

doesn’t tip the marble out.

•	 Doesn’t let the marble out: Roll 

small tubes of tape and build a chute 

to funnel the marble toward the 

opening. If necessary, adjust the tilt 

of the cup so the marble can roll out 

more easily.

•	 Misses the target: Since the marble 

is already moving forward along the 

zip line, it keeps moving forward as it 

falls. Make sure to take this forward 

motion into account as you choose 

a release.

www.nasa.gov NP-2020-04-2844-KSC