Design a Thermal Protection Shield
Design a Thermal Protection Shield
With Space Shuttle no longer available to service the International Space Station rockets are being used. The Ares rockets have been developed to do this task.
Ares 1 is going to be used to put the Orion crew exploration vehicle into a low Earth orbit from where it can either connect to the International Space Station or rendezvous with a rocket for an ongoing journey to the moon.
Aerospace engineers need to take into account the heat generated when the space craft move through the atmosphere at extreme speeds, both during launch and at re-entry, as without proper thermal protection the space craft could be destroyed.
Insulating blankets, foams and tiles are used to protect the spacecraft. Your task is to design a thermal protection system.
Before starting the design think about the methods of heat transfer and how they work. How will you minimise heat being transferred to the inside of the spacecraft?.
RESOURCES
You must make up a test stand to enable rapid alignment to be achieved when testing all the heat shields.
You will need for each group:
•Two 7cm x 7cm pieces of copper gauze 16 wires per inch (ebay)
•A test model, I used brass threaded rod, nuts and washers but had to buy on ebay as I could not source locally. I have made test rigs using steel and this just increases the time to fail as steel is not such a good conductor as copper.
•A 7cm x 7cm piece of aluminium foil.
•Marabu™ fun and fancy window paint.
•Smart colour from Mindsets.
•A stopwatch
ACTIVITY 1
Students will need:
•A 7 cm x 7 cm piece of copper mesh
•A test rig on which to mount your heat shield (see figure 1)
•A design sheet on which to record your design and ideas as to why it is a good design (see final page).
Nuts and washers
Colour Changeto hold
DowellingStickershield in place
Figure 1 The thermal protection system (TPS) model
Think:
Which part of the test rig represents:
•The inside of the space capsule?
•The outside of the spacecraft?
•The skin of the spacecraft?
(See figure 2)
Figure 2 Relationship of TPSmodel to the spacecraft
Thermal Protection Shield
Bunsen Flame
Using the information you have been given design and make your thermal protection shield
•Use the 7 cm x 7 cm piece of copper mesh to design a heat shield.
•Record your design giving reasons for your choices.
•Your time is limited to 10 minutes.
•Attach the heat shield to the test model using the nuts and washers on the test model.
•Bring your model with its heat shield to the front for testing when you are finished.
Three people need have stop watches and so they can time how long the heat shields last for. The heat shield fails when the part of the screw thread next to the dowel changes colour.
Alignment of the test model with the flame is critical. Your teacher will do this and your teacher will set up the carry out the test. You could observe the shield using the thermal Imaging camera.
How might this help inform your next design?
ACTIVITY 2
Improving the thermal protection shield
You will need:
•7 cm x 7 cm piece of copper mesh
•7 cm x 7cm piece of aluminium foil
•Test model
1Construct an improved heat shield by reflecting on your first design and thinking what could have improved it. Use the same materials.
2Attach the heat shield to the model using the nuts and washers as before.
3Test your design.
4Make a poster commenting on your designs and how good they were.
How well did your design work?
TEACHERS’ NOTES
This activity is based on an activity from NASA but has been adapted to make it reusable so it takes less technical time to prepare. The web site is:
Scroll down to thermal protection system to find the guide from NASA.
A Bunsen burner replaces the propane gas canister.
When you have a base constructed line up the assembly as shown below and check you get repeatable failure times with no protection in the range 3-6 seconds for your test model. Adjust the spacing between the top of the flame and the test model to achieve this. To make the results repeatable I used the Bunsen burner fully on.