Challenger Center: Garriott Science Challenge

Structural Design: Is the International Space Station rigid or does it flex (bend)?

Engineers on Earth design very long or tall structures (bridges and skyscrapers) to withstand environmental forces such as changes in temperature, high winds, and even earthquakes - in addition to bearing heavy loads.

The International Space Station is a very long and wide structure traveling at 17,500 miles per hour in space (360 feet across by 290 feet long) designed by NASA engineers to be durable and flexible. The space station is carefully designed to withstand a variety of forces such as changes in temperature (as it enters day and night every 90 minutes it experiences extreme hot and cold), drag due to its orbital velocity and the position of the solar arrays, flexing during re-boosts which raise the stations' orbital altitude (which degrades over time due to drag), and vibrations caused by maneuvers to adjust attitude (or orientation) using spacecraft jets.

Richard Garriott completed an experiment that showed how much the International Space Station structure flexes over time. He used a video camera and laser to illustrate how the ISS bends due to movement onboard.
In the Garriott Engineering Design Challenge, students design a very long or tall structure that can withstand flexing. Students should apply a force such as wind or shaking, and show the structure can survive! Videos of student designs are posted on the Challenger Youtube Site.

Student Challenge!

Design an Earth-based structure that can withstanding flexing due to environmental forces. Your structure can be either a bridge or a skyscraper. Then apply a force such as wind or shaking to ensure your structure can survive. Submit a video of your experiment for our YouTube Channel. Students may choose the materials from which to build their structure. Examples of building materials include: wood (toothpicks, dowels, popsicle sticks), metal (erector sets) or plastic (Lego bricks, K’NEX).

Size Restrictions

No matter what material you use for your structure, it should be:
For a bridge: four times longer than the length of the longest construction material
For a skyscraper: four times taller than the length of the longest construction material.
For example, if you use 6-inch popsicle sticks, your structure needs to be at least 2 feet long/tall. This will force you to use joints.
Maximum length or height of your structure - no longer/taller than ten times the length of the longest construction material used.
For example if you use 6-inch popsicle sticks, your maximum length or height is 5 feet.

Essential Questions

Things to consider when building your structure:

What forces act on structures here on Earth? (gravity, wind, earthquakes, vibrations, loads, etc.)
What forces act on structures in space? (drag, flexing, temperature, etc.)
How does the Space Station bend/flex?
How can structures on Earth be built so they can withstand forces acting upon them (gravity, wind, load, earthquakes, expansion/contraction due to heating/cooling)?
Do the number and type of joints in a structure affect how well it flexes to withstand forces?

Your video entry should include:

A description of how you built your structure.
A demonstration of 1-2 forces acting on your structure (ex. Use a fan to simulate wind, use weights to measure the load the structure can hold, shake your structure, etc.)
An analysis of why your structure did or did not withstand the forces applied to it.
How is the design of your structure related to the design of the International Space Station.

Bonus: If your structure breaks or falls apart, redesign it to withstand the forces.

Bonus: Using a mathematical formula show the flexing of your structure, and how if you keep adding length or height, how much more flexing would occur before it breaks or falls apart.

Classroom Activities

Elementary

Middle/High School

Student Resources