LESSON PLAN: NASA'S RETURN TO FLIGHT: TESTING INSULATING MATERIALS
Background, Activities and Critical Analysis
By Rene Flores, Educational Specialist at the National Aeronautics and Space Administration Johnson Space Center in Houston, Texas.

Subject(s): Physical Science, Physics, Technology

Time: 10-30 min Prep Time, 3 classes of 45-minutes

Lesson Objectives: Students will:

• Understand the basic components of the space shuttle stack.
• Understand the chemical fuel makeup and storage used on the external tank of the space shuttle.
• Be able to list pros and cons associated with using liquid fuel propulsion.
• Be able to discuss the findings of Columbia mission accident.
• Be able to discuss the safety improvements that have been made to NASA's "Return to Flight" Discovery mission.
• Understand the insulating qualities that must be considered in choosing the right insulation for space travel.

Overview:
On Feb. 1, 2003, the space shuttle Columbia broke up during re-entry over Texas, en route to landing at Kennedy Space Center. All seven crew members aboard perished. The Columbia accident revealed a major problem with the insulating foam used to connect the shuttle's external tank to the orbiter. Investigators found that foam falling off the tank had damaged Columbia's left wing, letting superheated gases into the orbiter upon reentry Redesigning the external tank became priority No. 1 as the agency prepared for the shuttle's return to flight.

As NASA's Return to Flight mission STS 114 approaches, the main change exists on the "bipod fitting" that connects the external tank to the orbiter. This mechanism is susceptible to icing due to the cold temperatures in which the liquid hydrogen and oxygen fuel must be stored. Engineers needed to find a way to prevent this icing from occurring; up until the Columbia accident, the critical connection points were protected with thick sheets of foam.

The experiment in this lesson allows you to step into the role of a NASA engineer to determine the best material for insulation. Since weight is always a concern for NASA, your insulation should be low-cost and as light as possible.

Materials:

• Four 2 or 3 pound coffee cans with plastic lids
• Four thermometers
• Four smaller cans to fit inside coffee cans
• Water
• Hot Plate
• Three insulating materials
• Funnel
• Articles for background reading
• Student Handouts: Image of the Space Shuttle Stack, Vocabulary list, Data Table

Various Insulating Materials:

• Corrugated cardboard strips
• Fiberglass
• Feathers
• Foam stuffing
• Pieces of Styrofoam
• Old clothing strips
• Shredded newspaper
• Aluminum foil
• Sawdust

To make these lesson plans better

Correlation to National Standards

Procedure

A. Online Articles for Lesson Objective Reading

Basic components of the space shuttle stack
The space shuttle stack consists of three main parts: the orbiter which houses the crew; a large external fuel tank which feeds into the main engines; and two solid rocket boosters which, during the first two minutes of launch, provide most of the shuttle's lift. All of the components are reused with the exception of the external fuel tank which burns up in the atmosphere after each launch. For further information on basic shuttle components, visit http://spaceflight1.nasa.gov/shuttle/reference/basics/index.html.

Chemical fuel makeup used on the external tank of the space shuttle
The fuel used for the space shuttle consists of liquid hydrogen and liquid oxygen as the oxidizer, which provides the propulsion for the shuttle. This combination provides the most efficient propellant for liquid rockets but falls into the cryogenic (super cold) category, which means both liquids must be stored at temperatures about 200 degrees below zero and both require delicate handling, special chilled storage tanks and strict temperature requirements to maintain their liquid form. More information on the external tank can be researched at the following Web site: http://spaceflight1.nasa.gov/shuttle/reference/basics/ssme/index.html.

Pros and cons of using liquid fuel propulsion
There are some distinct advantages and disadvantages to using liquid propellants over their solid counterparts.

The main advantages of using liquid propellant are they:
1) typically have higher impulse ratings than solid rockets, which makes them essentially more efficient, and
2) in cases of emergencies all liquid engines can be shut off before the fuel is all used up. This is very different from a solid rocket which, once ignited, cannot be shut off until all of its propellant has been consumed.

The disadvantages are:
1) the strict temperature requirements,
2) engines that are fueled by liquid tend to require many intricate pumps, and
3) liquid fuel usually requires a spark of some sort to start the combustion process.

More information can be found at: http://www.space.edu/projects/book/chapter6.html.

Columbia STS 107 results and safety improvements made to NASA's Return to Flight Mission
The Columbia accident revealed a major problem with the insulating foam used to connect the external tank to the orbiter. Investigators found that foam falling off the tank had damaged Columbia's left wing, letting superheated atmospheric gasses into the orbiter upon reentry After many safety improvements, NASA is aiming to launch the next shuttle within a launch window of May 22 to June 3, 2005. The enhancements designed to ensure the safety of the crew and the shuttle can be found at NASA's Web site: http://www1.nasa.gov/returntoflight/system/rtfupgrades_partI.html.

B. Testing Insulating Materials Experiment

This experiment allows students to take on the role of shuttle engineers to protect the orbiter from icing during launch. NASA now knows that the liquid fuels used must be contained in very cold temperatures. Therefore, in order to protect the shuttle, NASA engineers need a good insulating material. This experiment allows students to find the material that works best.

This experiment is a modified version from the NASA Explores Web site at http://nasaexplores.com.

1. Break students into four groups.

2. Assemble three insulation testers (coffee cans with lids) using a different type of insulation in each container. One should be used as your control and should not contain any insulation. For assembly: Place the smaller can into the coffee can. Put the insulation chosen around the smaller can. Cut a small hole in the coffee can plastic lid. Insert a thermometer through the hole, and put the lid on the coffee can. The thermometer should be inserted into the middle of the smaller can.

3. Use a hot plate to heat enough water in a beaker to fill all four small cans. Heat the water to 90-100º C.

4. When the water is hot, remove the plastic lid from the coffee can and use tongs or a hot pad to pour the hot water through a funnel and into the small can. Do not get the insulation wet. As soon as the hot water is poured into the small can, insert the thermometer and put the plastic lid back on the coffee can.

5. Record the initial temperature of the hot water on the data table provided.

6. Continue recording the water temperature every 5 minutes for 30 minutes.

7. Repeat with the other three insulator testers.

C. Discussion and Conclusion

After conducting their experiment, students will share their results and compare them to the results of other groups.

Students should discuss:
1) What went well and what problems did they confront?
2) What changes would they make to the experiment if they had to do it again?
3) What new insulating materials would they like to try?
4) Is the insulation that achieved the best results low in cost and as light as possible?

Extension Activities
For further information on the shuttle's return to flight or many other space-related topics, NASA provides live videoconferencing programs through its Digital Learning Network at http://nasadln.nmsu.edu/dln/.

Correlation to National Education Standards:
Science: 3b, 6a
Math: 5a, 6b, 6c, 12a, 22b
Technology (ITEA): 20c, 20d, 20e

About the Author: Rene Flores serves as an educational specialist and on-camera host for NASA's Digital Learning Network. Through NASA he has been able to connect and provide lessons for students across the nation. He comes from San Antonio, Texas, where he taught earth science at Christa McAuliffe Junior High School in the Southwest Independent School District. There, he served as Science Department chairman and established a partnership with NASA through the Middle-School Aerospace Scholars Program. He also has been invited to serve as a speaker on the education panel for the national conference of the American Astronautical Society.

To find out more about contributing to this site, contact Leah Clapman at extra@newshour.org.