Hands-on Activity Spacecraft Design:
Beat the Heat!

Learning Objectives

After this activity, students should be able to:

• Discuss why it is important to study other planets and discover more about our solar system.
• Describe the engineering challenges associated with sending a spacecraft to either Mercury or Venus.
• Explain how engineers protect spacecraft from the harsh conditions found on Mercury and Venus.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS: Next Generation Science Standards - Science

International Technology and Engineering Educators Association - Technology

State Standards

Materials List

For the test box:

• 1 thin piece of transparent Plexiglas for testing window (available at hardware stores)
• 1 medium-sized cardboard box, such as a copier paper box
• hairdryer
• duct or packaging tape
• paper towels or plastic liner, to catch drips in the bottom of the box

Each group needs:

• 1 thin square pat of butter
• plastic egg, or another small closed plastic container to represent a space capsule or probe

For the entire class to share:

• scissors
• masking tape
• glue
• construction paper
• aluminum foil
• toothpicks
• assortment of balsa wood, fabric and cardboard pieces
• assortment of Styrofoam cups
• thermometer to measure inside test box temperature
• oven mitt, to remove warmed space capsule form the test box
• timing device

Pre-Req Knowledge

A basic introduction to Mercury and Venus and their characteristics is helpful, such as provided in the associated Solar System unit lesson 3, Mercury and Venus. It may also be helpful to provide a brief review of heat transfer concepts, including conduction, convection and radiation.

Introduction/Motivation

For the past 60 years, humankind has explored and studied the solar system beyond its own planet Earth. Recently these investigations have been performed by satellites designed to go to other planets and send back information about the conditions found on other worlds. Many of these missions require the satellite to collect data on a planet's temperature, atmosphere and soil composition. By carrying out these explorations, we satisfy our desire to answer questions about the unknown, and we begin to better understand our universe and how it works. In addition, we can learn more about our own planet, Earth, by comparing the conditions found on other planets.

While many planets have been studied in detail since the launch of the first satellite in 1957, Mercury and Venus are two planets that are especially difficult to study and, as a result, are more unknown to us. In fact, only one satellite has ever flown to Mercury — Mariner 10 in 1974 — and only half of Mercury's surface has been mapped.  Also, although eight Soviet Venera spacecraft have landed on Venus, none have survived longer than about two hours in the harsh Venusian conditions!  

So why are these two planets so difficult to study? It is mostly because of their locations. Remember that Mercury and Venus are the two planets closest to the Sun, so their surfaces are extremely hot! Mercury has an average temperature of 800 ^oF (430 ^oC) during the day while Venus has an average of 900 ^oF (480 ^oC). Did you notice, even though Venus is twice as far from the Sun as Mercury, its average temperature is much hotter than Mercury's average? This is because Venus is surrounded by a thick atmosphere composed of carbon dioxide that creates a greenhouse effect. This means that it traps the heat and does not let it dissipate back into space.

In addition to the extremely hot temperatures, sending satellites to these planets requires a large amount of energy to slow them down as they approach the planets. As satellites get closer and closer to the Sun, they begin to speed up, just as an object speeds when dropped from a tall height on Earth. If the satellites did not have rocket engines to slow them down, they would zoom right past the planet and continue orbiting the Sun.

So how do engineers design a spacecraft to overcome these problems? This is the question you will answer today by creating a spacecraft design for a planet such as Venus and Mercury. On Venus, the temperatures are high enough to melt lead and the atmospheric pressure is 90 times that on Earth! Of the eight spacecraft that landed on Venus, four of them managed to take photographs (six, altogether) of the terrain surrounding their landing site because windows made of diamonds protected the camera lenses. Certainly, if we want to send a space probe to another planet, we would like it to last longer than two hours. So, engineers are continually testing ideas to make spacecraft able to survive harsh conditions that exist on planets such as Mercury and Venus.

Procedure

Before the Activity

• Gather materials.
• Construct a planet simulation test box. Choose a box size that can easily fit three or four student spacecraft, each containing a probe or space capsule, at a time. Replace one side with a thin piece of transparent Plexiglas (use duct or packaging tape to secure it). Make the following cuts into the box: a round hold to accommodate a hairdryer nozzle (to heat the inside air and increase the inside air pressure), a small round hold to permit insertion of a thermometer (to take the inside air temperature), a small hole or vent opening to keep too much pressure from building up, and a flap big enough to permit temporary access to easily move the spacecraft in and out (see Figure 1). As an alternative, use a toaster oven set at a very low temperature.

With the Students – Step 1: Design

1. Present the student challenge: Today your engineering team is challenged to design a spacecraft that can resist the harsh conditions found on planets such as Mercury and Venus. The longer your spacecraft survives the harsh conditions of the planet, the more time we have to collect information and data about the planet. Use your knowledge about the conditions found on Mercury and Venus to design a thermal protection system for a probe that will be sent there. This spacecraft must be carefully designed to protect the sensitive devices — such as a camera, antenna and sensors — that collect planet data. All the teams will test their designs to determine which design works best and why.
2. As a class, brainstorm ideas about how to best protect the precious spacecraft components from the hazardous planet conditions; namely the high temperatures and high pressures of Venus. (See the ideas provided in the activity embedded assessment portion of the Assessment section.)
3. Present the construction materials from which students may choose. Explain that after they have finished their design and are ready to build, each team will be given a slice of butter and a plastic egg. The butter represents the vital components of the spacecraft and the test box represents the harsh conditions found on Mercury or Venus. Their goal is to use the materials to design and create a thermal protection system to protect the butter from the very hot and high pressure conditions in the planet simulation test box.
4. Divide the class into teams of two or three students each. Direct the groups to choose an idea from the class brainstorming activity to use in the design of their spacecraft.
5. Ask each team to draw a sketch of how their spacecraft will look using the given materials.

With the Students – Step 2: Build

6. Give each group a pat of butter and a plastic egg. Instruct them to place the butter inside the egg (representing a probe or space capsule) and build their spacecraft and thermal protection system to protect the butter when it's in the test box. Remember, the butter represents the vital components of the spacecraft and the test box represents the harsh conditions found on Mercury or Venus.
7. Give students some time to create their spacecraft with the given materials.

With the Students – Step 3: Test

8. Lay a plastic liner or paper towel in the bottom of the test box to collect any leaking melted butter.
9. Place several teams' spacecraft into the test box and use the hairdryer to raise the temperature and, if possible, the pressure inside the test box.
10. Have students use the thermometer to read the increasing temperature inside the test box.
11. Check the spacecraft after 2 minutes, 4 minutes, etc. Repeat the planetary simulation test with the next set of spacecraft. The spacecraft whose butter lasts the longest without melting is the best because it kept the precious cargo (butter) safest longest.
12. Observation notes: Before the end of the activity, students should realize that the butter is best protected if it does not touch the walls of its spacecraft. While waiting, explain to students that this is because the hot atmosphere begins to heat up the spacecraft walls first, then, if the butter touches the walls it begins to melt the butter by conduction. Instead, if the butter is suspended inside the capsule by string or toothpicks, the heat must conduct through the air to raise the temperature of the butter. This takes longer since air is a poor conductor and hence, the butter does not melt as fast.
13. To conclude, lead a class discussion, comparing teams' spacecraft results and discuss what materials and designs worked best to protect the butter from melting. See post-activity questions and activities in the Assessment section.

Vocabulary/Definitions

engineer: A person who applies her/his understanding of science and mathematics to creating things for the benefit of humanity and our world.

greenhouse effect: A process that traps heat inside the atmosphere due to solar radiation travelling through the atmosphere and heat radiation unable to pass out of the atmosphere due to atmospheric carbon dioxide and other gases.

spacecraft: A vehicle designed for travel or operation in space beyond the Earth's atmosphere or in orbit around the Earth.

thermal protection system: The part of a spacecraft that protects it from very hot external temperatures.

Assessment

Pre-Activity Assessment

Prediction: Ask the students:

• Which planet do you think is the hottest in the solar system? (Answer: Venus. Even though Mercury is closer to the Sun, Venus' dense atmosphere traps heat and raises the surface temperature to nearly 1300۫^oF [700 ^oC].)

Activity Embedded Assessment

Brainstorming: As part of the activity, lead a class brainstorm session to come up with creative ideas for how engineers might build a spacecraft so that it protects its vital internal components. How can we incorporate what we know about heat transfer (conduction, convection, radiation) to protect the interior from heat? (Possible answers: Build large radiators that absorb most of the heat instead of the interior components. Insulate the spacecraft with Styrofoam so that heat cannot penetrate inside. Put the spacecraft in a really cold part of the room just before placing it in the test box. Protect the internal components by not having them touch the space capsule walls.)

Prediction: As a class, examine each batch of spacecraft before they go into the test box. Ask the students:

• Which of these models do you predict will best protect the probe's internal data collection components (butter) from the heat and pressure on the planet (inside the box)? (Answers will vary.)

Post-Activity Assessment

Discussion Question: Solicit, integrate, and summarize student responses.

• How long did it take for your spacecraft to malfunction (that is, for the butter to melt)?
• Which spacecraft protected its internal components the best and why?
• How might you re-engineer your design so it lasts (protects the butter from melting) longer?

Re-Engineering: Ask students how they could improve their spacecraft design to work better, and have them sketch or test their ideas.

Safety Issues

• Use an oven mitt or make sure the space capsules have cooled before removing them from the test box.

Troubleshooting Tips

As an alternative to the test box, use a toaster oven set at a low temperature, being careful to not melt the plastic eggs.

Activity Extensions

Ask students to research the longest time a spacecraft has survived on the surface of Venus. (Answer: Venera 13 survived for approximately 127 minutes before its signal was lost.)

Engineers design instruments and devices to gather information about places that are too difficult or dangerous for people to go. What if you could not go in your basement, house, backyard, school or classroom for some reason? How do we collect data from deep in an ocean, volcano or space? How would you design something to go in without you and gather information so that you could tell the conditions inside? (Ideas: Robots with cameras and sensors, tiny camera on stick to slide in doors or windows, mirror to reflect images, telescopes, probes for oceans, volcanoes and space.) Assign students to write a paragraph describing an existing tool or device, and another paragraph to describe another tool or device that does not exist, but that an engineer could create.

References

Copyright

Contributors

Supporting Program

Acknowledgements

The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education, and National Science Foundation GK-12 grant no 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.