Документ1 Challenge
Ares version U.S. Space Academy (1.5 hour)
Spring 2013
Upon completion of this activity trainees will be able to . . .
1.
DESCRIBE: how heat tiles protect the orbiter.
2.
DEFINE: ablation, convection, conduction and radiation.
3.
DESIGN: a thermal protection system that uses these concepts.
Science Content Standards Grades 5-8

Science as Inquiry
Abilities necessary to do scientific inquiry
Understanding about scientific inquiry

Physical Science
Transfer of Energy

Science and Technology
Abilities of technological design
Understanding about science and technology
2 prefabricated test stands 2 propane tanks with igniters
Eggs – 1 per work group Mesh – large-hole steel and aluminum screen
Felt Cotton fabric and balls
Aluminum foil Joint compound (spackle)
Paper – poster board, thin, masking Lasagna
Cork Steel wool
Timer Safety goggles
Small bowls or plates Scissors
Ruler Pencils
Yarn
Data sheet Foam models – orbiter and capsule
INTRODUCTION


USSRC Proprietary

Документ1 Challenge
Ares version U.S. Space Academy (1.5 hour)
Spring 2013
P R O C E D U R E : :
PREPARATION
Gather the supplies. The box with most of the supplies for this session should be kept in the Habitat-2 briefing closet. Lay supplies out on a table for trainees to inspect and select from. There are 2 test stands – they need to be set up outside on the fire mats – a table is optional. Do not set burners in place until everyone goes outside.
The team will work in work groups that were created for other Engineering Challenge activities.
INTRODUCTION ( 20 minutes)
Discuss thermal protection systems.
The trainees may already know that the shuttle and other spacecraft travel at 17,500 mph (or 28,000 kmph). When the spacecraft reenters, it uses the air to help it slow down.
This heats the air immediately around the orbiter to temperatures of in excess of 3,000ºF
(1,649ºC), hot enough to melt steel.
On the orbiter thermal protection is provided by tiles – about 24,000- and NOMEX blankets. The tiles come in three colors – each one withstanding differing amounts of heat. White tiles can withstand heat up to about 1,200ºF (650ºC), black tiles up to 2,300
F (1,260ºC) and gray tiles up to about 3,600ºF (1,649ºC) . Location of tiles is determined by the amount of heat an area receives upon re-entry. White blankets made of coated
Nomex felt reusable surface insulation are used on the upper payload bay doors, portions of the mid-fuselage and aft fuselage sides, portions of the upper wing surface and a portion of the OMS/RCS pods and is protective up to temperatures of 700ºF (371ºC).
The shuttle TPS is reusable, and the tiles are like marshmallows made of glass—10% silica (sand) and 90% air—a marshmallow is essentially a ball of sugar puffed up with air—the TPS tiles are similar, microscopic air pockets make the glass block lighter than
Styrofoam but highly resistant to heat.
In the Apollo era, capsules did not fly in the same way during return. The capsule landed with a more ballistic fall that generated heat of 5,000-6,000 ºF (2,760 ºC). The interior of the command module must be protected from the extremes of environment that will be encountered during a mission—the cold of space (c.-280ºF / -173ºC) and the heat of the direct rays of the sun (280ºF / 138 ºC), and the intense temperatures of reentry
(5,000ºF / 2,760ºC). The interior remained a comfortable 70º F (21ºC).
The principal task of the heat shield that forms the outer structure is to protect the crew from the fiery heat of reentry—heat so intense that it melts most metals. The ablative material makes up the shield is a phenolic epoxy resin, a type of reinforced plastic. This material turns white hot, chars, and then flakes away, taking the heat with it.
The heat is absorbed and shed by the shield and does not penetrate to the capsule interior.
The command module enters the atmosphere with its base down; this is covered by the thickest part of the heat shield. The heat shield varies in thickness from ½ to 2¾ inches thick (1.3-7 cm) and weighs about 3,000 pounds (1,360 kg).
Inform trainees that either one of these forms of TPS would be a good idea for their challenge.
USSRC Proprietary

Документ1 Challenge
Ares version U.S. Space Academy (1.5 hour)
Spring 2013
Conduction, Convection, Radiation: Tell the trainees that they will be designing a
Thermal Protection System of their own, but before they do, they should know a few things about how heat and thermal protections systems work. Review definitions of:
Conduction: Heat travels through Solids by conduction. Some objects are better conductors of heat than others. During the design challenge, more contact between objects means more heat transfer through conduction.
One example of conduction is accidentally leaving a metal spoon in a pot of boiling soup—while initially cool to the touch, the handle can burn you if the heat is allowed to travel up the length of the spoon.
Convection: Heat moves through Fluids through convection. “Fluids” means any matter that conforms to the shape of its container—(liquids and gasses, like water or air). As the fluid warms, it expands—the same mass now takes up a greater volume—meaning it becomes less dense. The warmer, less dense material rises or floats to the top of the fluid and the denser, cooler fluid moves down to take its place. During the challenge, convection can help to carry heat away.
These convection currents are responsible for weather patterns and are how hot air balloons function. As a side note, convection cannot happen in microgravity . Without gravity nothing rises or sinks, regardless of relative density. Special fans are required to cool computer equipment and to warm food, as air of different temperatures will not circulate on its own.
Radiation: Heat also travels in waves, or through radiation. Radiant energy (like from a r r a d i i a t t o r r ) is how energy from the sun warms the Earth despite the 93 million miles of the vacuum of space that lie in between.

If you are near a hot object and you touch it and get burned, that is C o n d u c t t i i o n .
.

If you feel the warm air currents rising from it, that is C o n v e c t t i i o n .
.

If you are near enough to the heat source to feel the warmth on your skin, even though the air is still, that is R a d i i a t t i i o n .
.
Thermal Protection Systems (Challenge Intro):
Tell the trainees that they will be building a thermal protection system out of the materials available on the table. Pick up one of each material and hold it for trainees to see and name it. All materials are already cut to size except the yarn. The abilities of each design will be tested with the blowtorch.
TPS size requirements:
The trainees’ shields can be no thicker than a standard pencil: ¼” (7 mm.). An easy way to test this is to see if the shield will fit under a ruler balanced on two pencils. Each shield will be secured to the test stand and a raw egg placed behind it on the stand. The shields will be subjected to 3 minutes of heat from the blow torch. Eggs will then be removed from the stand and cracked to see how much damage was done by the heat.
USSRC Proprietary

Документ1 Challenge
Ares version U.S. Space Academy (1.5 hour)
Spring 2013
:
Build Credits:
The “company” that can build a working shield for the least expense (the “lowest bidder”) is at an advantage.
Groups receive any unused credits times 2
(If they used 75 points of their 100 build credits, they have 25 points left over.)
25 unspent points x 2 = 50 points to start
Survival:

Award 200 points for survival if the inside is uncooked and the shell is unscorched

Award 100 points if the shell is lightly scorched, and/or the inside has a cooked mass smaller than your pinky fingernail.

Award 0 points if the shell is cracked or blackened, or the egg has a cooked mass inside that is larger than your pinky fingernail.
D E M O s s : : Allow each work group to select one material. Move outside to test stands.
Show the trainees the test stand including where and how their shield will be attached and where the egg will sit. Place materials one at a time in stand and burn so that trainees can see how some materials will respond to heat and fire. Inform trainees that their completed TPS will be heated for three (3) minutes.
Build (20-25 minutes): Return to the classroom and give students their data sheet.
Explain that trainees have a budget of 100 credits to purchase materials. They will be responsible for keeping track of what was spent on the data sheet. Left-over credits will apply to their score, but they should build with the intent of protecting the egg. When trainees are done, have each group report on what materials they used and how they believe the TPS they built will work. Have them tally their remaining points.
T e s s t t : : (20 minutes): Take trainees outside to test their TPS. Place eggs and TPS, time for
3 minutes. When eggs are cool, crack all and check the interior. See above for scoring.
Have trainees complete their data sheet and give to Crew Trainer prior to leaving.
Discuss what worked and what did not.
*Safety notes:
Be sure to set the orange cones to keep trainees back.
NEVER burn TPS indoors.
In care of rain, stands can be set up under the roof by sick bay.
If there is lightning, the trials cannot be done. Ask Crew Trainer to help you gently store them in the closet and arrange another time for the trial. Trainees may not be available and you may need to get results to them.
References:
Boeing employees: Carista Brake and Jason Powell
Melissa Snider
Mary Mast
From Julie Clift, Earth to Orbit http://edc.nasa.gov/
Jason Jirsa. Education Specialist, USSRC. 2005. jasonj@spacecamp.com
USSRC Proprietary

Документ1 Challenge
Ares version U.S. Space Academy (1.5 hour)
Spring 2013
Reading
Mathematics
Reading
Mathematics
Reading
Mathematics
Mathematics
Science
Science
GRADE 5
1. Demonstrate reading vocabulary knowledge, including recognition of multiple-meaning words.
4. Use a wide range of strategies and skills, including using text features to gain meaning; summarizing passages, and drawing conclusions to comprehend fifth-grade informational and functional reading materials.
6. Use text features, including indexes, tables, and appendixes, to guide interpretation of expository texts.
Number and Operations
2. Solve problems involving basic operations on whole numbers, including addition and subtraction of seven-digit numbers, multiplication with two-digit multipliers, and division with two-digit divisors.
3. Solve word problems that involve decimals, fractions, or money.
G RADE 6
4. Recognize the use of text elements, including implied main idea, explicit cause-effect relationships, and persuasive techniques, in sixth-grade informational and functional reading materials.
17. Use listening skills for remembering significant details, directions, and sequences.
Number and Operations
1. Demonstrate computational fluency with addition, subtraction, multiplication, and division of decimals and fractions.
2. Solve problems involving decimals, percents, fractions, and proportions.
Algebra
3. Solve problems using numeric and geometric patterns.
G RADE 7
15. Demonstrate listening skills, including identifying the main idea, detail, purpose, and bias in group discussions, public speeches, and media messages.
Number and Operations
1. Demonstrate computational fluency with addition, subtraction, and multiplication of integers.
G RADE 8
Number and Operations
1. Use various strategies and operations to solve problems involving real numbers.
Physical Science
1. Identify steps within the scientific process.
 Applying process skills to interpret data from graphs, tables, and charts
 Measuring dimension, volume, and mass using Système International d'Unités (SI units)
Identifying examples of hypotheses
7. Describe states of matter based on kinetic energy of particles in matter.
 Explaining effects of temperature, concentration, surface area, and catalysts on the rate of chemical reactions
G RADES 9-12
Physical Science
5. Describe physical and chemical changes in terms of endothermic and exothermic processes.
6. Identify characteristics of gravitational, electromagnetic, and nuclear forces.
7. Relate velocity, acceleration, and kinetic energy to mass, distance, force, and time.
 Describing action and reaction forces, inertia, acceleration, momentum, and friction in terms of Newton’s three laws of motion
12. Identify metric units for mass, distance, time, temperature, velocity, acceleration, density, force, energy, and power.
Biology
1. Select appropriate laboratory glassware, balances, time measuring equipment, and optical instruments to conduct an experiment.
 Describing the steps of the scientific method
 Using appropriate SI units for measuring length, volume, and mass
Physics
4. Describe quantitative relationships for velocity, acceleration, force, work, power, potential energy, and kinetic energy. http://www.alsde.edu/html/CoursesOfStudy.asp
USSRC Proprietary