Lesson Shielding from Cosmic Radiation:
Space Agency Scenario

Learning Objectives

After this lesson, students should be able to:

• Define different types of radiation, especially those in cosmic rays.
• Explain why shielding from radiation is important for astronauts traveling in space.
• Articulate how their role and responsibilities will contribute to the overall team accomplishing this mission.

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

Worksheets and Attachments

Introduction/Motivation

[Show the Shielding from Cosmic Radiation Presentation; narrate the following slides.]

Slide 2: Let’s start by thinking about a few things… What’s your favorite movie/book about space? [Let students offer answers.] What’s something about space that fascinates you? [Let students offer answers.] What do you want to do after high school? [Let students offer answers.]

Slide 3: Why do we go to space? [Let students offer answers. Potential answers: explore the unknown, scientific advancement, economic growth, national security, etc.] There are many different reasons humans want to go to space: to explore and learn about the unknown, to discover new worlds, to push the boundaries of scientific and technical limits, to develop new technologies and industries, to create economic growth, to foster peaceful connections with other nations, to provide and maintain national security, and to address fundamental questions about our place in the universe and the history of our solar system.

Slide 4: A major obstacle we face when we go into space is radiation. Although we have the technology to get rockets into space, we don’t have the technology to protect astronauts from radiation.

Slide 5 and 6: [Use following information sourced from NASA: https://www.nasa.gov/analogs/nsrl/why-space-radiation-matters]

What is Radiation?

Outside the protective cocoon of the Earth’s atmosphere is a universe full of radiation – it is all around us. Say the word "radiation" to three different people, and you'll probably get three different reactions. Your aunt may tell you how radiation destroyed her cancer. Your neighbor might mention the "duck and cover" procedures of his day. And your comics-loving friend will explain how gamma rays turned Bruce Banner into The Hulk. Radiation comes in many forms and is all around us, all the time. But what is radiation?

Radiation is a form of energy that is emitted in the form of rays, electromagnetic waves, and/or particles. In some cases, radiation can be seen (visible light) or felt (infrared radiation), while other forms—like x-rays and gamma rays—are not visible and can only be observed with special equipment. Although radiation can have negative effects both on biological and mechanical systems, it can also be carefully used to learn more about each of those systems.

What is Space Radiation?

Space radiation is different from the kinds of radiation we experience here on Earth. Space radiation is comprised of atoms in which electrons have been stripped away as the atom accelerated in interstellar space to speeds approaching the speed of light – eventually, only the nucleus of the atom remains.

Space radiation is made up of three kinds of radiation: particles trapped in the Earth’s magnetic field; particles shot into space during solar flares (solar particle events); and galactic cosmic rays, which are high-energy protons and heavy ions from outside our solar system. All of these kinds of space radiation represent ionizing radiation.

How much Space Radiation are Astronauts Exposed to?

Beyond Low Earth Orbit, space radiation may place astronauts at significant risk for radiation sickness, and increased lifetime risk for cancer, central nervous system effects, and degenerative diseases. Research studies of exposure in various doses and strengths of radiation provide strong evidence that cancer and degenerative diseases are to be expected from exposures to galactic cosmic rays (GCR) or solar particle events (SPE).

Milli-Sievert (mSv) is a form of measurement used for radiation. Astronauts are exposed to ionizing radiation with effective doses in the range from 50 to 2,000 mSv. 1 mSv of ionizing radiation is equivalent to about three chest x-rays. So that’s like if you were to have 150 to 6,000 chest x-rays.

Where Does Radiation Come From?

Radiation can be created by humans (microwaves, cell phones, radios, light bulbs, diagnostic medical applications such as x-rays) or naturally occurring (the Sun, radioactive elements in the Earth’s crust, radiation trapped in the Earth’s magnetic field, stars, and other astrophysical objects like quasars or galactic centers).

Earth’s biggest source of radiation is the Sun. The Sun emits all wavelengths in the electromagnetic spectrum (EM). The majority is in the form of visible, infrared, and ultraviolet radiation (UV). Occasionally, giant explosions, called solar flares, occur on the surface of the Sun and release massive amounts of energy out into space in the form of x-rays, gamma rays, and streams of protons and electrons. This is called a solar particle event (SPE). These solar flares can have serious consequences to astronauts and their equipment, even at locations that are far from the Sun.

Non-Ionizing versus Ionizing Radiation

Radiation can be either non-ionizing (low energy) or ionizing (high energy). Ionizing radiation consists of particles that have enough energy to completely removing an electron from its orbit, thus creating a more positively charged atom. Less energetic, non-ionizing radiation does not have enough energy to remove electrons from the material it crosses.

Examples of ionizing radiation include alpha particles (a helium atom nucleus moving at very high speeds), beta particles (a high-speed electron or positron), gamma rays, x-rays, and galactic cosmic radiation (GCR) from space. Examples of non-ionizing radiation include radio frequencies, microwaves, infrared, visible light, and ultraviolet (UV) light. While many forms of non-ionizing and ionizing radiation have become essential to our everyday life, each kind of radiation can cause damage to living and non-living objects, and precautions are required to prevent unnecessary risks.

Why is Ionizing Radiation More Dangerous than Non-Ionizing Radiation?

While non-ionizing radiation is damaging, it can easily be shielded out of an environment as is done for UV radiation. Ionizing radiation, however, is much more difficult to avoid. Ionizing radiation can move through substances and alter them as it passes through. When this happens, it ionizes the atoms (knocks electrons out of them) in the surrounding material with which it interacts.

Ionizing radiation is like an atomic-scale cannonball that blasts through material, leaving significant damage behind. More damage can also be created by secondary particles that are propelled into motion by the primary radiation particle.

The particles associated with ionizing radiation in space are categorized into three main groups relating to the source of the radiation: galactic cosmic rays, solar flare particles, and radiation belt particles (Van Allen Belts) trapped in space around the Earth.

What Is Galactic Cosmic Radiation?

Galactic Cosmic Radiation (GCR) is a dominant source of radiation that must be dealt with aboard current spacecraft and future space missions within our solar system. GCR comes from outside the solar system but primarily from within our Milky Way galaxy. GCR is composed of the nuclei of atoms that have had their surrounding electrons stripped away and are traveling at nearly the speed of light. Another way to think of GCR would be to imagine the nucleus of any element in the periodic table from hydrogen to uranium. Now imagine that same nucleus moving at an incredibly high speed. The high-speed nucleus you are imagining is GCR. These particles were probably accelerated within the last few million years by magnetic fields of supernova remnants.

In summary, GCR are heavy, high-energy ions of elements that have had all their electrons stripped away as they journeyed through the galaxy at nearly the speed of light. They can cause atoms they pass through to ionize. They can pass practically unimpeded through a typical spacecraft or the skin of an astronaut.

Are We Protected from Space Radiation on Earth?

Yes, but not entirely. Life on Earth is protected from the full impact of solar and cosmic radiation by the magnetic fields that surround the Earth and by the Earth’s atmosphere. The Earth also has radiation belts caused by its magnetic field. The inner radiation belt, or Van Allen Belt, consists of ionizing radiation in the form of very energetic protons—by-products of collisions between GCR and atoms of Earth’s atmosphere. The outer radiation belts contain protons and electrons. As we travel farther from Earth’s protective shields, we are exposed to the full radiation spectrum and its damaging effects.

In addition to a protective atmosphere, we are also lucky that Earth has a magnetic field. It shields us from the full effects of the solar wind and GCR. Without this protection, Earth’s biosphere might not exist as it does today, or would at least be limited to the subsurface. 

What Factors Determine the Amount of Radiation Astronauts Receive?

There are three main factors that determine the amount of radiation that astronauts receive or how radiation affects astronauts. 

They include:

• Altitude above the Earth – at higher altitudes the Earth’s atmospheric protection is no longer present and the magnetic field is weaker, so there is less protection against ionizing particles, and spacecraft pass through the trapped radiation belts more often.
• Solar cycle – the Sun has an 11-year cycle, which culminates in a dramatic increase in the number and intensity of solar flares, especially during periods when there are numerous sunspots.
• Individual’s susceptibility – researchers are still working to determine what makes one person more susceptible to the effects of space radiation than another person. This is an area of active investigation.

Slide 7: Show this video “Does Radiation Make Air Travel Dangerous?” - https://youtu.be/GoEk7Uu8a2M

Slide 8: Show this video “How Cosmic Rays and Balloons Started Particle Physics” - https://youtu.be/Asc-tArn0nk

Slide 9: So, what are we doing? In this set of activities, you will all join a space agency and create a spacecraft that will further our perceptions of space and earth! You will form two groups in a mock “space race” to send astronauts to space. Your mission is to design shielding to protect astronauts from the effects of radiation.

Slide 10: How will we do this? We are going to be sending up a payload to near space! You will be designing and constructing these payloads and measuring the radiation up in the atmosphere. But we’re also going to be shielding the Geiger counters from radiation, using various materials as the shielding. Your job is to determine which materials would work the best.

To test your payload, we are going to use high altitude balloons to study cosmic radiation on our astronauts and take basic measurements. This makes research much less expensive than using rockets or very high-altitude aircraft like the U2. However, high-altitude balloons cannot do everything that is needed, as they are limited to 120,000 feet or so, but they can still do quite a lot.

Slide 11: Given several different materials, cost sheets, and Arduino micro-bits, you will design a shield and measure its effectiveness using a Geiger counter Arduino attachment.

Slide 12: In this project, you each will assume a different role, including director, economic advisors, computer scientists, engineers, Research & Development (R&D) scientists, public relations (PR) personnel, and others. Together, your agency will design a payload with shielding material and a way to measure how effectively the shielding functions. In addition, a control payload needs to go along. The payloads will be loaded onto a high-altitude balloon and launched. The Geiger counters will collect radiation data and additional sensors will collect altitude data as the balloon travels to close to 100,000 feet. After the payload is recovered, you will get a chance to analyze the data collected. This data will show you how effective your shielding is against cosmic radiation. The knowledge that your project requires will come from research that you do -- research about cosmic rays and their effects on your body, materials used to block radiation, human space travel, computer programming, Arduinos, radiation sensors, high-altitude ballooning, and more!

I will now move you into your space agencies and assign a Director.  [Move students into different space agencies.]

Now that you are in your groups you each will need to take on a role in your agency. Take a look at the Space Agency Roles and Responsibilities Sheet and think about which roles you want to take on. Remember that you don’t need to have experience to take on a role. You can learn your role during these activities. So, think about doing something you haven’t done before! [Give students 5-10 minutes to read through Space Agency Roles and Responsibilities Sheet]

Now your space agency needs to elect your professionals. Talk amongst your agency and hold a quick vote of your agency members to assign each role career in the agency. If there are any issues, the Director will assign each member a role. [Give student 5-10 minutes to sort out their roles.]

Great! Next your agency needs to come up with a name. Your director will lead your agency’s discussion.  [Give student 5-10 minutes to decide on a name. Have each Director hand in an agency name to the teacher.]

We are now going to start familiarizing ourselves with our roles. Take a look at the Space Agency Roles and Responsibilities Sheet and start discussing with your agency what goals, design, budget, and logo plans you have. 

Lesson Background and Concepts for Teachers

The history of space travel is a vast topic, full of history, crucial decisions, and actions with consequences. There are several excellent books on the subject, some published by NASA, as well as documentaries, movies, and websites. We encourage you to select what works best for your students, whether that be a web tour, assigned reading, or viewing a film.

The problems posed by cosmic radiation are well described in the following NASA education web page: https://phys.org/news/2017-09-space-risky-business-human-body.html

High altitude balloons can aid the study of cosmic radiation by making basic measurements and research much less expensive than using rockets or very high-altitude aircraft like the U2. However, high-altitude balloons cannot do everything that is needed, as they are limited to 120,000 feet or so, but they can still do quite a lot.

What types of materials best block space radiation (cosmic rays)? These include materials containing a great deal of hydrogen, such as plastics, and there is even a proposal to use certain radiation tolerant algae. A good reference is this NASA pdf file: https://www.nasa.gov/pdf/284275main_Radiation_HS_Mod3.pdf

The data collected by this payload are from Beta particles and Gamma rays. Note that the Geiger counter begins operating as soon as the battery is plugged into the Arduino. Every time the Geiger counter intercepts a Beta particle or Gamma ray, the SD card logs (a) the time (in milliseconds) since the battery was powered, (b) the intercept count, and (c) the counts per minute. It also logs two Geiger counter measurements: (d) the radiation dosage in terms of micro-Sieverts per hour (μSv/h) and (e) the radiation dosage error.

The radiation dosage is the measurement of most interest to this project. For example, background radiation dosages at the ground in Laramie, Wyoming where this project was tested (7,200 ft / 2220 m above sea level) were generally around 0.05–0.1 μSv/h. Higher in the atmosphere, radiation measurements from an unshielded Geiger counter can exceed 2.0 μSv/h, more than two orders of magnitude larger than at the ground.

The following resources may be helpful to add details to the various roles of the space agency:

1. Director - monitor agency’s progress and create a payload presentation (see Space Agency Roles and Responsibilities Sheet)
2. Engineer(s) - build the payload (see Payload Manual Guide)

Note: Engineer(s): Refer to the Types of Engineers and Salaries Sheet for students to familiarize themselves with what engineers do and approximately how much they are paid. [Optional: Although the type of engineers is not specified in this activity, students can be asked to pick the most appropriate engineer-type from the handout.] Additionally, Engineer(s) will benefit from having a copy of the payload manual to refer to for instructions and pictures, but if resources are short, one copy should be furnished for them to share and refer to as needed.

3. R&D Scientist(s) - research the available materials and the mystery element; research the best way to secure the payload and how the various materials perform at low temperatures (see Space Agency Roles and Responsibilities Sheet)
4. Computer Scientist(s) - program the Arduino to write on SD memory card (based on the tutorials they have completed; see Payload Manual Guide)

Note: The Computer Scientist(s) will need to complete a tutorial about Arduinos. Computer Scientist(s) must learn about and program an Arduino. Please see the Payload Manual Guide for full details regarding Hardware and Materials, Software and Coding, and Additional Materials. These are the names of the pertinent sections in the Payload Manual. At a minimum, the payload manual should be printed out so that all students can refer to it to gain an idea of the overall goal. Ideally, each Computer Scientist will have a copy, as the manual contains specific code. To get students started familiarizing themselves with an Arduino and programming it, ask that they watch tutorials about the matter. There are several out there. Here are a few we recommend:

https://www.arduino.cc/en/Tutorial/HomePage?from=Main.Tutorials

https://www.programmingelectronics.com/tutorial-3-arduino-ide-and-sketch-overview/ https://www.instructables.com/id/Learning-to-Program-the-Arduino-Part-1/

5. Economic Advisor(s) - track spending and revenue from social media; monitor budget (see Space Agency Roles and Responsibilities Sheet)

Note: Economic Advisor(s): must determine the price for the material “purchased.” Prices for raw material fluctuate daily based on several factors; more information may be found at this link: https://www.bls.gov/mxp/metal.pdf. To find the price of the material purchased on a given day, type in “price of aluminum (for example)” into the search bar. The results will show the price, which may be entered into the budget spreadsheet (see Space Agency Roles and Responsibilities Sheet) and multiplied to obtain the overall cost.

6. PR Team - design logo(s); publicize on social media (see Space Agency Roles and Responsibilities Sheet)            

Note: The PR Team will create a poster with their agencies logo on it and continue to update their social media accounts.

Agency’s “earn” money based on “advertising” through social media. [Our school set up two Instagram accounts and encouraged the student body to “like” their posts. For every like, the agency “earned” money.] For exact amounts, please see the Space Agency Roles and Responsibilities Sheet. The PR team creates posts and photos for the accounts and builds excitement from the rest of the school. The PR team communicates with the economic advisor to report current stats regarding “likes” and so forth that could be incorporated into the budget and result in that agency being able to “purchase” more supplies.

Associated Activities

• Shielding from Cosmic Radiation: Part 1 - Building the Payload - Students embark on an ambitious design project to build a payload that measures the effect of shielding from cosmic radiation via a high-altitude balloon launch test.
• Shielding from Cosmic Radiation: Part 2 - High-Altitude Balloon Launch Test - Students embark on an ambitious design project to measure the effect of shielding from cosmic radiation via a high-altitude balloon launch test. Students prepare their payloads for launch, making sure batteries are charged, payloads are complete, flight predictions have been made and approved, etc.
• Shielding from Cosmic Radiation: Part 3 - Post-Launch Analysis - Students examine the radiation data collected from a balloon launched into near space to see if cosmic radiation shielding designs worked. Students explain their findings, which might require some research to show if this observation is correct and why.

Lesson Closure

By the end of this lesson, you all should be able to define different types of radiation. You will select your role in the space agency. Start discussing with your agency what goals, design, budget, and logo plans you have. You will need to design a payload that will test shielding from radiation, strategize how to build the payload, make trade-off decisions based on budget, and evaluate the payload design. The next activity will be to design and build the payload while staying within your budget and within the time allowed to test your design on launch day.

Vocabulary/Definitions

Arduino: Microcontroller using open-source hardware/software that fits this project perfectly due to its weight and ease of use.

atmosphere: A layer of gases that protects and surrounds the Earth.

electromagnetic radiation: ER comprises the waves of the electromagnetic field, which includes visible light, x-rays, infrared, and gamma rays. Gamma rays are a component of cosmic rays.

Geiger counter: A device used to detect and measure ionizing radiation.

particle radiation: Particle radiation is made up of alpha and beta particles. An alpha particle is basically a highly ionized helium atom. A beta particle is just a free electron. Alpha particles are deadly but stopped much more easily than beta. We are working with cosmic radiation, which is composed primarily of beta particles.

Assessment

Pre-Lesson Assessment

Think-pair-share exercise: Ask students the question “What obstacles do space agencies face when sending astronauts into space?” Allow two minutes for individual thought; two to three minutes to discuss ideas with elbow partner; and five to ten minutes for each pair to share their ideas with the entire class.

Lesson Embedded (Formative) Assessment

Writing: Ask students the questions: “What is radiation, what are the different types, and why is it relevant?” Students use this prompt to write a one-minute paper.        

Post-Lesson (Summative) Assessment

Space Agency Debrief: Short formative assessment asking students about the goals of the mission and their roles within their respective space agencies.  

Lesson Extension Activities

Data spreadsheets from previous launches using different types of test radiation shields and Geiger counter measurements will be made available for additional data analysis and discussion.

Additional Multimedia Support

The WYSpaceGrant YouTube channel has videos of previous high-altitude balloon launches that could be used to catch students’ attention and also provide an example of what high-altitude ballooning is. The videos may be accessed at this link: https://www.youtube.com/user/WYSpaceGrant/videos.

Copyright

Contributors

Supporting Program

Acknowledgements

Much of the equipment and training to develop the Wyoming NASA Space Grant balloon program were provided by StratoStar.

This material was developed based upon work supported by the National Science Foundation under grant no. 1821566—the LIFT (Learning to Integrate Fundamentals through Teaching) Project, Wyoming NASA Space Grant Consortium, University of Wyoming. Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.