Space nutrition

National Aeronautics and Space Administration

Scott M. Smith | Janis Davis-Street | Lisa Neasbitt | Sara R. Zwart

Illustrations by Marco Zambetti | Graphic Design by Cory Duke
© Copyright 2012 NASA. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any 

form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the written prior permission of the author.

Printed in the United States of America.

ISBN: 978-1-4269-9788-4

Library of Congress Control Number: 2011918860

Written by: Scott M. Smith, Janis Davis-Street, Lisa Neasbitt, Sara R. Zwart

Illustrations by Marco Zambetti

Graphic Design by Cory Duke
1

Preface.....................................................................................................................................................................3

Section One............................................................................................................................................................5

Understanding Space Flight...................................................................................................................................5

Adapting to Space Flight.........................................................................................................................................6

Space History (and Present) ...................................................................................................................................8

Mercury ...............................................................................................................................................................9

Gemini ...............................................................................................................................................................10

Apollo ................................................................................................................................................................11

Skylab................................................................................................................................................................12

Apollo-Soyuz Test Project ..................................................................................................................................13

Space Shuttle ....................................................................................................................................................14

Shuttle-Mir Program...........................................................................................................................................15

International Space Station ................................................................................................................................16

Space Food .............................................................................................................................................................17

Space Walks: The Smallest Spacecraft..............................................................................................................22

Section Two..........................................................................................................................................................24

Research ..................................................................................................................................................................25

An Experiment is Born – Observation.................................................................................................................26

What’s a Hypothesis ..........................................................................................................................................26

Experiment ........................................................................................................................................................27

Data Collection and Analysis of Results..............................................................................................................27

Conclusions.......................................................................................................................................................28

An Example Observation and Hypothesis...........................................................................................................28

Space Flight Research...........................................................................................................................................30

Nutrition Research..................................................................................................................................................33

Assessing Nutritional Status...............................................................................................................................33

Nutrition and Bone.............................................................................................................................................34

How Stable Is That Food?..................................................................................................................................35

Research in Space vs. on the Ground: What’s an Analog?.............................................................................37

Bed Rest............................................................................................................................................................37

Under the Sea....................................................................................................................................................38

The Bottom (or Top) of the World! ......................................................................................................................39

Artificial Gravity ..................................................................................................................................................40

Around the Globe ...................................................................................................................................................42

Summary..................................................................................................................................................................42

Table of Contents
2

Section Three......................................................................................................................................................43

Space Flight Nutrition ............................................................................................................................................43

What’s so important about nutrition?..................................................................................................................44

Nutrients...................................................................................................................................................................46

Macronutrients...................................................................................................................................................46

Energy (calories).................................................................................................................................................46

Vitamins....................................................................................................................................................................48

Vitamin D...........................................................................................................................................................48

Vitamin K ...........................................................................................................................................................50

Other vitamins....................................................................................................................................................52

Minerals....................................................................................................................................................................53

Calcium (and Bones!).........................................................................................................................................53

Iron (and Blood!).................................................................................................................................................54

Antioxidants, Radiation, and Oxygen..................................................................................................................57

Radiation ...........................................................................................................................................................57

Oxygen damage (oxidation)................................................................................................................................59

Summary ...........................................................................................................................................................60

Section Four.........................................................................................................................................................61

Being Healthy Is Not Just About Nutrition .........................................................................................................61

Exercise Lab ......................................................................................................................................................62

Cardiovascular Lab ............................................................................................................................................63

Neurosciences Lab ............................................................................................................................................63

Behavior and Performance Lab..........................................................................................................................64

The Next Frontier—Exploration............................................................................................................................65

Glossary.......................................................................................................................................................................66

National Science Education Standards..................................................................................................................71

Science Content Standards K-12............................................................................................................................71

Space Nutrition Book Educator Guide ...................................................................................................................73

About the Authors......................................................................................................................................................78

About the Illustrator ...................................................................................................................................................81

Acknowledgments .....................................................................................................................................................81

...Table of Contents
3

The “Adopt-a-Classroom” project was started as a way to help bring upper elementary and intermediate 

school students closer to space research, and specifically to the Calcium Kinetics experiment that flew on 

Space Shuttle mission STS-107. The Space Nutrition newsletter was the focus of this project, and the first 

issue of Volume 1 was released in October of 2001. The newsletter was created by scientists in NASA’s 

Nutritional Biochemistry Laboratory. All of the newsletters are available online at: http://go.nasa.gov/QS1KW1. 

The first issue of Volume 2 of the newsletter was released in September 2002 and highlighted the 

importance of safety at NASA, in the context of a delay in the STS-107 mission. The monthly newsletters 

reflected our building excitement as the mission drew nearer. The January 2003 issue was sent out the 

week of the launch.

The tragic loss of Columbia and her crew on February 1, 2003, was devastating for those involved with the 

crew and the mission, as well as for the nation. We soon realized the impact that the newsletters had on 

the students and teachers that we interacted with. The cards and letters we received from students, many 

of which were described in the issues released following the tragedy, were a source of strength for us here 

at NASA, and we also worked to provide the students a sense of understanding of the tragedy, of where 

we were and how we were doing, and a broader vision for the future of space flight and the Space Shuttle. 

The bonds created, or perhaps just realized, in the wake of the loss of Columbia, have in part provided us 

the strength to carry on with this dream of space exploration. The final issues of Volume 2 reveal the initial 

forward movement.

In the years following those first two, the newsletter evolved to provide a monthly update of ongoing 

research activities related to nutrition and space, including flight and ground experiments. Many topics were 

covered, from general summaries of experiments and other Nutritional Biochemistry Laboratory activities 

to information about individual nutrients. Among the several aims of the newsletters, one aim was to 

provide a sense of the teamwork it takes for an experiment to succeed, the time required for planning and 

preparation, and the care and dedication needed to fly an experiment on the Space Shuttle or International 

Space Station. We also sought to provide information about nutrition, and how it affects life on Earth as well 

as during space flight. Highlighting the scientific research process and the amazing work going on in orbit, 

on both the Space Shuttle and the International Space Station, was also a key objective. In general, we 

wanted to provide a sense of participation for the students, to help them understand and appreciate how 

science might affect their lives and how they may someday wish to pursue goals similar to those of us here 

at NASA. For multiple reasons, the monthly newsletter production stopped in September of 2007. 

Preface
4

This book represents the spirit of the newsletter, formatted into a book with sections that describe the 

exciting world of doing nutrition research in space—Understanding Space Flight, Doing Nutrition Research in 

Space, and Space Flight Nutrition.

We hope that this book will engage and excite students, teachers, and parents about the work going on in 

our tiny corner of NASA. The final writing of this book was completed in 2011, the 50th anniversary of human 

space flight, the 50th anniversary of the Johnson Space Center, the 30th anniversary of the first Space 

Shuttle mission, and the year of the final Space Shuttle mission. We have been honored, awed, and humbled 

to have the opportunity to work with the space program over the years, in some small way. We hope that 

between the initial newsletters and this book, that readers will have the opportunity to share in our journey of 

scientific and space exploration.

...Preface
5

Section One

Understanding Space Flight
6

Adapting to Space Flight

When flying in space, the human body feels that it is in an environment very different from the ground. 

You spend your whole life on the ground with gravity—and in space, all of a sudden that changes. The body 

does a great job of quickly realizing this, and it starts to change to get used to this new world—a process 

we call adaptation. Adaptation to space flight affects almost every part of the body in one way or another: 

heart, muscles, bones, stomach, blood, even your inner ear (the part that helps you keep your balance). 

This can make the first few days of space flight very rough, sort of like living on a roller coaster!

Most of these changes don’t have a negative effect while you are in space, but some can have large effects 

when you land on Earth again. For example, your body needs less blood while you are weightless, probably 

because it is easier to get blood (and oxygen) to all parts of the body without gravity. This adaptation takes a 

week or two. During that time your body lowers the number of blood cells and the amount of fluid circulating 

in your blood vessels. Some of the fluid (that is, water) is shifted out of the blood vessels and into other 

areas of the body (like into cells) or out of the body (in urine). This works fine in space, but when you come 

back to Earth, your body won’t have enough blood, so we need to be careful that the astronauts don’t faint 

on their return to Earth’s gravity! To help prevent problems, about 45 minutes before returning to Earth, the 

astronauts drink a liter of salty solution to help them during and soon after landing. 
7

What is “adaptation”?

Adaptation is a process something undergoes 

to become better suited to a new environment.

What does it mean 

to “orbit”?

An orbit is the path an object takes around 

another object. We say that the Shuttle and 

International Space Station orbit around the 

Earth, and they do this once every 90 minutes.

Wheels Stop

Adjusting to Earth’s gravity after a space 

mission can be very hard, similar to getting 

off a roller coaster. One astronaut said 

that “gravity was no friend of mine” soon 

after landing.

The muscles also weaken during space flight. This is called 

“muscle atrophy.” We’re still working to understand the 

details of why this happens, but it seems that because the 

body doesn’t use muscles the same way in weightlessness 

as on Earth, the unused muscles will weaken. Although this 

doesn’t matter while an astronaut is orbiting the Earth, it is 

very important for walking around after landing. This is harder 

on crews on the International Space Station (ISS), who stay 

in space for months. The longer the flight, the weaker the 

muscles get. Astronauts exercise hard every day to try to 

avoid these changes. 

Understanding and preventing the negative changes 

that occur during space flight is an important job. 

Researchers at the Nutritional Biochemistry Laboratory at 

NASA’s Johnson Space Center in Houston spend a lot of 

time on this, because good nutrition may be one way to 

help keep astronauts healthy during space flight. In the next 

chapters, we will tell you all about the work going on in 

the Nutritional Biochemistry Laboratory, and also what 

good nutrition means to you!
8

The Space Nutrition Team – Lin, Tim, Thea, and Diego – are here to guide 

us through the history of space flight, and through the many historical aspects 

of space nutrition. This team was created and developed with the help and 

love of our illustrator.

8

Space History (and Present)
9

Did you know?

Russian cosmonaut 

Yuri Gagarin (depicted 

here) was the first 

human in space. 

He launched from 

Russia on April 12, 1961. 

Although he was in space for only a short 

time (108 minutes, to be exact!), this was a 

big step that paved the way for the future 

space programs.

Did you know?

The first American orbital 

flight, part of Project 

Mercury, was flown by 

John Glenn. His spacecraft, 

the Friendship 7, was 

launched on an Atlas 6 

rocket. He orbited the Earth 

3 times for a total of almost 5 hours in 

space. John Glenn was also NASA’s 

first astronaut to eat anything in space. 

Foods enjoyed by Mercury crew members 

included bite-sized cubes, freeze-dried 

powders, and semi-liquids in aluminum 

tubes that looked like toothpaste tubes.

Mercury

Mercury was the United States’ first space program that sent 

humans to space. Mercury astronauts were 

launched into space on either a Redstone 

or Atlas rocket, depending on how far 

they traveled. 

Alan Shepard was the first American 

in space. He took his first trip to space 

less than 1 month after Yuri Gagarin’s 

flight, and it lasted 15 minutes and 28 

seconds. That first flight was a suborbital 

flight, meaning that it did not orbit the Earth. 

The Mercury program ended with Astronaut Gordon Cooper 

completing 22 orbits around the Earth and staying in space for 

a whole day (a little over 34 h).
10

Gemini

The Gemini program, Project Gemini, was created to bring NASA one step closer to going to the moon. 

It included the first 2-person missions, and the first space walk by an American!

Foods used in Project Gemini were a little better than the original items developed for 

Project Mercury. They included foods like shrimp cocktail, chicken and vegetables, 

pudding, and apple sauce.

...Space History
11

Apollo

In 1961, when the U.S. had had about 15 minutes of space flight experience, President Kennedy challenged 

us to get to the moon by the end of the decade. With tremendous teamwork and an 

outstanding effort, in 1969 the Apollo 11 crew landed on the moon. At 4:18 p.m. EDT 

on July 20, 1969, Neil Armstrong radioed the first words from the Moon: “Houston, 

Tranquility Base here. The Eagle has landed.” Just under 7 hours later, he took the 

first steps out of the lunar module and proclaimed “That’s one small step for man, 

one giant leap for mankind.”

The Apollo astronauts were the first to have hot water in space, so the variety of 

space foods increased even more. On Christmas Day, 1968, the Apollo 8 crew ate a 

package of turkey and gravy and ate with spoons. The Apollo crews enjoyed bread slices 

with sandwich spreads and cheddar cheese spreads, and even frankfurters. Fruit juices were also added 

to the menu.

Did you know?

This figure depicts a very famous 

photograph. Neil Armstrong was not only 

the first person to step onto the moon, 

he was also the first lunar photographer, 

taking this picture of Buzz Aldrin, the 

second person to step onto the moon.
12

Skylab

The first space station built by the U.S. was Skylab, depicted in the figure below. The goals of the Skylab 

program were to prove that humans could live in space for long periods of time, and to 

perform scientific experiments. Astronauts on Skylab used specially made equipment to 

keep an eye on, and better understand, what happens to the body when it is exposed 

to weightlessness for a long time. They also measured radiation from the sun and 

observed the Earth from space. 

Skylab had one of the best space food systems. One area on the station had space 

for a dining room and table. A refrigerator and freezer were also available for storing 

food, and therefore the menu could be more extensive. The Skylab astronauts could 

choose from 72 different food items, including steak and vanilla ice cream.

...Space History
13

Apollo-Soyuz Test Project

The Apollo-Soyuz program was the first joint space program of the U.S. and Russia, and resulted in one 

mission. The mission was 9 days (July 15-24, 1975), but a great deal of planning went into 

those 9 days. 

During the Apollo-Soyuz mission, a U.S. Apollo spacecraft launched from the U.S. and 

docked (that is, connected) with a Russian Soyuz spacecraft that had launched from 

Russia. Engineers had to design a special docking module that would fit onto both 

spacecrafts. The figure below depicts this mission, with the Apollo capsule on the left 

and the Soyuz capsule on the right. Photos of this event are unavailable, as there was 

no third spaceship to take the picture from!

The Apollo-Soyuz docking module was basically a 3-meter-long (about 10 feet) tunnel, and it served as an 

airlock between the two vehicles. This was required because the interiors of the two vehicles had different 

atmospheres, with different pressures and different mixtures of gases, and the airlock allowed the 2 crews to 

meet in space without a sudden pressure change.

The Apollo and Soyuz crews shared meals and performed experiments together. This program was a big 

success overall, and paved the way for the future when these nations would work together again in space.
14

Space Shuttle

The Space Shuttle was the world’s first reusable spacecraft. Shuttle missions were 5 to 16 days long, and 

had as many as 8 crew members. The part of the Space Shuttle that had wings was 

called the “orbiter.” Inside the orbiter was the crew compartment (that is, the place 

where the crew members worked, ate, and slept). The crew compartment had 

2 levels: the flight deck and the mid-deck (or middle deck). The flight deck was 

“upstairs,” and was where the commander and pilot (and 2 other astronauts) sat 

and controlled the flight, and could see out the windows. The mid-deck was 

“downstairs,” and was where most experiments were conducted, where the 

“kitchen” was, and where the bathroom was. 

Shuttle astronauts prepared their food in the galley on the orbiter’s mid-deck. 

The galley was a kitchen area, and had a water dispenser that could deliver warm or cool water. It also had a 

convection oven to warm foods. This oven was hot enough to warm foods, but it wouldn’t be hot enough to 

bake foods - like cookies! 

Astronauts on Shuttle flights had a 7-day menu cycle, which meant that the foods they ate were the same 

every 7th day. 

Did you know?

This is what some of the foods look like that we 

currently use. Many of the foods are packaged in a 

special container that can be used as a bowl after 

water is added to rehydrate the food. All of the foods 

are wrapped in special materials to make the foods 

last longer. Also, notice that the straws have a special 

one-way valve to prevent liquid from escaping when 

they are not in use.

>> The first Space Shuttle mission, STS-1, launched 

April 12, 1981. The longest Shuttle mission ever was 

17.5 days on STS-80 in 1996.

...Space History
15

Shuttle-Mir Program

The Shuttle-Mir Program was a series of space missions from 

1994 to 1998. It consisted of 11 Space Shuttle 

flights to the Russian space station Mir. 

The goals of this program were to learn 

how to work with international partners, 

gain experience in successfully living in 

space for many months, and conduct 

scientific experiments related to biology, 

weightlessness (also called “microgravity”), 

and Earth’s environment. 

The crew members aboard Mir had their choice of American or 

Russian food. Astronaut Andy Thomas described the food this 

way: “The Russian foods were really good. The Russian soups 

were just outstanding.” He went on to say “It was really a 

good selection of food, actually. The food is largely canned 

food and rehydratable foods, much like you might use on a 

camping trip or something like that, and I had more 

than enough to eat.” 

Did you know?

 >> Sergei Krikalev (depicted below) was the 

first Russian cosmonaut to fly on the Space 

Shuttle, in 1994. This mission was called 

STS-60, and the Commander for this flight 

was Charlie Bolden. Commander Bolden 

participated in experiments to study fluid 

balance in the body during flight. He went 

on to be appointed by President Obama to 

become the NASA Administrator in 2009!
16

International Space Station (ISS)

The International Space Station (ISS) is a giant environment for living and working in space. The ISS was 

built in sections called “modules” that were taken to space either in the Space Shuttles or on 

Russian launch vehicles. The first module was launched in 1998, and construction of the 

ISS was completed in 2011. Even though the ISS is traveling almost 200 miles above 

the Earth at 17,500 miles per hour, on a good night you can see it with just your eyes! 

Check out NASA’s Web sites for when the ISS might pass over your head!

Exploring space is a huge challenge. It requires teamwork from countries around 

the world. Just as the United States has NASA, other countries have their own space 

organizations. The international space station organizations represent 16 countries, called 

the international partners (IPs). For the ISS, the IPs are the Canadian Space Agency, the 

European Space Agency, the Japanese Aerospace Exploration Agency, the Russian Federal Space Agency, 

and the United States’ space agency—NASA. All of the partners work together to accomplish one task: 

learning more about space. 

The ISS crews are international as well. Six crew members live on the ISS, and they come from the U.S., 

Russia, Canada, Japan, and Europe. The U.S. and its IPs make new foods to try to increase the variety of 

foods available to crew members. 

The parts of the ISS were built in different countries. For example, the 

Canadian Space Agency built a robotic arm; the European Space Agency 

built the Columbus Laboratory module; the Japanese Aerospace 

Exploration Agency built an experiment module that is composed 

of three segments and is known as Kibo, which means “hope” 

in Japanese. The Russian Federal Space Agency built the 

Functional Cargo Block, FGB for short, known as Zarya 

(the Russian word for sunrise), and NASA built the lab module 

called Destiny. These huge pieces were never near each other 

until they were attached in orbit!

Did you know?

Since November 2000, astronaut and 

cosmonaut teams have lived on the ISS 

continuously. That really is quite amazing! 

...Space History
17

Did you know?

There are special rules for creating 

new space foods:

 • Minimize crumbs

 • Minimize packaging and trash 

volume

 • Minimize the weight of the food

Did you know?

“Dehydrated” means that the 

water has been removed and the 

solid matter has been left behind. 

“Thermostabilized” means that 

foods have been heated a certain 

way to destroy bacteria in the food 

that could make it spoil.

None of the U.S. space foods used today are 

served in tubes as they were on the early flights, 

like Apollo and Gemini missions.

Space foods on the International Space Station are either 

rehydratable, thermostabilized, or in natural form. A rehydratable 

food is one that is dehydrated, meaning all of the water has been 

taken out. You might be familiar with some of these, like packets 

of hot cocoa mix or dried noodle soups. To eat one of these items, 

you must rehydrate it, meaning you must add the water back. 

Thermostabilized foods are heated to high temperatures and 

packaged in cans or closed pouches. Examples of thermostabilized 

foods are canned ravioli and soups. We also use some foods in their 

natural form, that is, just like they are in nature (or at the grocery 

store). A food in its natural form is in a vacuum-sealed package, 

meaning all of the air has been removed so that it stays fresh for a 

long time. These foods include nuts and dried fruit.

The ISS crew members eat international foods, as the crew 

members are from many different countries. Right now, half of the 

space food items on board the ISS are American foods and half 

are Russian foods. Japanese, European, and Canadian food 

items are available also. The astronauts and cosmonauts have 

more than 300 food items to choose from. 

Space Food
18

...Space Food

Preparing food to eat in weightlessness is a challenge. Crumbs are not allowed, as they can float around the 

cabin and could float into someone’s eye (or nose) or into instruments, or clog air vents. Also, the food must 

not float away while an astronaut is trying to eat it, so packages and foods are designed to make this less of 

a problem in space. Another challenge for food system developers is trash. Wrappers and empty packages 

must be compressible to minimize the amount of trash on the spacecraft. The garbage truck doesn’t stop 

by the International Space Station, and there are very few opportunities to get trash off the vehicle. In fact, 

trash is disposed of only when space vehicles such as the Space Shuttle, the Soyuz capsules, and other 

cargo vehicles visit the ISS and then depart. This happens about once a month, and even these vehicles 

have limited amounts of space available, so trash must be as compact as possible. These are just a few of 

the challenges of developing space foods. The NASA Space Food Team does a great job of meeting these 

challenges, and of developing foods that the astronauts will like during their space missions. 

Food storage is a big issue for space travelers. Until recently, the ISS had no freezers or refrigerators for 

food, so the food has had to be “shelf stable” and not likely to spoil for at least 6 to 12 months. Food for a 

Mars mission will need to be stable for up to 5 years. Recently, a small refrigerator-freezer known as MERLIN 

(Microgravity Experiment Research Locker/Incubator) was flown to the ISS. It can be used to store a small 

amount of fresh food and drinks. This is especially helpful for drinks, which up to now have been pretty much 

room temperature. Nothing beats a cold glass of juice!

Taste and texture—how the food feels in your mouth—are very important for space travelers. Many taste 

tests are conducted on Earth when new foods are being developed for space travelers. When adapting to 

space flight, some astronauts have reported that their tastes changed, and that in space they tended to like 

spicier foods. One of the reasons for this is related to congestion that astronauts sometimes have, similar to 

when you have a cold and your nose is stuffy. Most of the ISS crew members say that this is troublesome 

only in the early days of flight, and that after a week or two, foods taste great.
19

Before each mission, astronauts select their favorite foods from the available flight foods, and they taste the 

foods they have selected to make sure that they really do like them. The most popular space food is shrimp 

cocktail, in part because of the spicy sauce!

Other challenges in developing space foods are making sure that they are tasty, have good nutrient content, 

and can be easily prepared. Another big challenge, especially as we begin to think about sending humans to 

the moon and Mars, is shelf life (how long the foods will stay fresh). Even for an International Space Station 

flight, the foods have to be able to sit on the shelf (a shelf in the pantry, not in the refrigerator or freezer) and 

still be tasty for at least 9 months. It will be even longer for a Mars mission. Can you imagine going to the 

grocery store, filling your pantry with food—and not going back to the store for a year, or 2 or 3? 
20

Food scientists in the Space Food Systems Laboratory at the Johnson Space Center have created another 

success story. They have developed special tortillas that taste good after almost a year. Tortillas in space 

work great for making sandwich roll-ups (a regular sandwich with two slices of bread would take three hands 

to make—otherwise one slice will float away!). The scientists keep these tortillas fresh with special packaging 

that includes an oxygen scavenger. An oxygen scavenger is a chemical that traps oxygen, and the lack of 

oxygen in the packaging prevents mold from growing.

Some space foods are irradiated. These foods are packaged and then exposed to a source of radiation 

that kills any mold or bacteria on the food, allowing it to be safe to eat for a long time. No radiation stays 

on the food. This is like when you go to the doctor to get an x-ray, once the x-ray is taken, there is no 

radiation on you. 

Did you know?

Some space foods are irradiated. 

These foods are packaged and then 

exposed to a source of radiation 

that kills any mold or bacteria on 

the food, allowing it to be safe to 

eat for a long time.

“Irradiated” means to expose 

to radiation.

...Space Food
21

There are many types of radiation besides x-rays. One type that is found in space is cosmic radiation. 

The spacecraft (and astronauts) are shielded from most of the harmful cosmic radiation. This shielding 

prevents astronauts from getting vitamin D from sunlight as they would here on Earth. We have to take 

extra care to make sure astronauts get enough vitamin D from foods. We’ll take a look at vitamin D later 

in the book.

Some forms of cosmic radiation do get through the spacecraft wall. In addition to being a concern for the 

health of the astronauts, this radiation is also a concern for the food. Radiation might affect vitamins and 

nutrients in the food before it is eaten, and the foods might not taste good, or might have fewer nutrients 

than we think. If this happens, we’ll need to find ways to better shield the foods, either by packaging each 

item in a new material, or by making new large protective containers that could be used for many food items.
22

Space Walks: The Smallest Spacecraft

Space walks, or what NASA calls “extravehicular activity” (EVA), are a 

very important part of many space missions. When astronauts need to go outside the 

Space Shuttle or International Space Station, they have to put on a special suit that acts like a personal 

spacecraft. The EVA suit provides pure oxygen for the astronauts to breathe, and is cooled with a special 

suit underneath that can have cool water circulating throughout it. During an EVA, astronauts can be in these 

suits for up to 10 hours.

Space Walks
23

Did you know?

There are more than 326 million trillion 

gallons (1 gallon = 3.79 liters) of water

 on Earth!

The Neutral Buoyancy Lab is 202 feet 

(62 meters) long, 102 feet (31 meters) wide, 

and 40 feet (12 meters) deep. It holds 6.2 

million gallons (230 million liters) of water, 

and the water in the NBL is recycled 

every 19.6 hours. The water is kept at a 

temperature from 82 to 88 degrees.

To train for doing EVAs, astronauts need a place that simulates 

the space environment where they can wear their EVA suits. 

The Neutral Buoyancy (bo-yun-see) Lab is a giant swimming 

pool for diving that allows astronauts to train for space missions 

involving space walks. Full-scale models of the International 

Space Station and Space Shuttle are at the bottom of the 40-ft 

pool, and there is even a mission control center that directs 

the activities of the dives. When something is buoyant, it has a 

tendency to float or rise when submerged in water. What does 

it mean to be neutrally buoyant? It means to have an equal 

tendency to float and to sink. When an item is neutrally buoyant, 

it is very easy to move the item while it is under water—much 

like moving an object in space. 

Astronauts training in the Neutral Buoyancy Lab wear space 

suits similar to those used during space flight EVAs, and 

they breathe high levels of oxygen as they would on EVAs. 

Although we need oxygen to survive, too much oxygen can 

cause damage to cells in the body. We can measure the amount 

of damage by looking at chemicals in the blood and urine 

to see how much damage was done by the excess oxygen. 

Antioxidants are chemicals found in foods, such as vitamin C or 

vitamin E, that can reduce damage from oxygen. Colorful fruits 

and vegetables such as melons, grapes, peppers, tomatoes, 

and berries are rich in antioxidants.
24

Research

In this Section, Lin, Tim, Thea, and Diego—the Space Nutrition Team—help us understand 

more about the world of research – nutrition, and in general!

24

Section Two
25

Biochemistry is a fancy word for studying how living organisms work—all 

the way down to the chemicals in the cells that make up the body. 

Nutritional biochemistry is the study of how nutrients in food affect how 

our bodies work. Every cell in your body requires many different vitamins 

and minerals as well as energy to keep you alive and healthy.

In one sentence, the job of the Nutritional Biochemistry Laboratory is to figure out how much of each 

nutrient (the calories, protein, vitamins, calcium, other minerals...you name it) the body needs during space 

flight—in other words, the nutrient requirements for space flight. To figure out what the requirements are, the 

people in our laboratory do research. As we find out new information about these nutrient requirements by 

doing research, the information is handed over to specialists in NASA’s Space Food Systems Laboratory. 

They have the tough job of developing foods and menus that will not only meet the nutrition requirements, 

but also obey the many other special rules that are made for space foods. These rules are discussed in more 

detail in the Space Food section ahead.

Research 

So what is meant by the word “research”? To conduct research, scientists do experiments to learn about 

things in the world. Just as you do in your science fair experiments, researchers learn new things by asking 

questions, testing theories or hypotheses, observing how things happen, and making conclusions about 

things they learned. Once you know and understand how something works, you can predict how it will 

behave in the future. This process is called the scientific method. You use the scientific method if you’ve ever 

entered a science fair competition, and it is exactly what we at NASA use every time we do an experiment—

on the ground or in space. In the next few paragraphs, we’ll walk you through the scientific method and we 

will also describe how we used this process for one of our experiments. 

Research
26

...Research

An Experiment is Born – Observation

Observation is the first step of the scientific method. We propose experiments when we want to answer 

questions about observations we have made. The answers that come from doing experiments are more 

reliable answers than answers that are only an estimate, or a guess. Science is based on answering 

questions with evidence or confirmed information. The more evidence you have, the better your 

conclusions will be. 

What’s a Hypothesis?

A hypothesis is an “educated” guess. It could be a guess based 

on a previous experience or a similar situation. It’s more reliable 

than answering a question by saying “because I think so.” 

>> Example of an observation

Summertime is hot! When it is hot, people like to drink ice-cold 

lemonade more often. Let’s say you had a lemonade stand and you noticed 

that you had a lot more sales one week than you did the next week. You would 

then try to think of differences between the weeks that could explain the rise in 

sales, and there would likely be many. Maybe you would decide that the outside 

temperature made a difference and people are more thirsty when it is warmer. 

The next step is to test your hypothesis that warmer temperatures influence 

lemonade sales at your stand.

To test your hypothesis that temperature affects your sales, you could record 

(write down or enter into a computer) the outside temperature along with the 

number of sales each day. If you had an indoor lemonade stand, you could adjust 

the room temperature to be higher one week and lower the next week.

If you used a thermometer that was broken or didn’t work properly, then your 

results and conclusions would not be accurate.
27

Experiment

The experiment is the next step of the scientific method. An experiment is the testing of your hypothesis in 

a controlled manner. This means that you have a well-defined process or procedure for each step of your 

experiment, so that someone else could repeat it. There are several ways to perform each experiment. 

When scientists propose to do an experiment, their proposal is reviewed by other scientists who are experts 

in that area. These reviewers can suggest ways for the scientists who proposed the experiment to make their 

experiment better. The best experiments are well planned and reviewed many times by many people and 

groups. This is just one step in the process of getting an experiment from an idea to space and back!

Data Collection and Analysis of Results

At the end of your experiment, you always want to have some 

sort of measurable outcome. Collecting good information 

from your experiment is important. Using tools that 

have been calibrated, or checked to make sure 

they are accurate, is important. 

When you finish collecting information, or data, 

then you will want to determine what it all means. 

This process is called analysis. You could 

make a graph and plot daily temperature 

versus number of drinks sold, which 

would be an easy way for someone 

to quickly look at your data and 

interpret what, if anything, your 

experiment tells you the conclusion 

of your experiment. 
28

...Research

Conclusions

Drawing conclusions and reporting results of experiments is very important. Even if your experiment doesn’t 

give you data that tells you that your hypothesis is correct, the information is still valuable and others can 

learn from it. Writing a report of the whole process—observations, hypothesis, details of the experiment, 

showing the data you collected, and putting it all together in a conclusion—is something scientists do 

regularly so they can let others know what they are doing. It’s exactly what you would do for a science fair. 

Scientists publish their reports in scientific journals. If the project is related to studying bones, then a 

bone journal would be appropriate. If it’s related to leaves, then a plant journal would be appropriate. 

There are hundreds of scientific journals, and each has specific areas of interest. The Nutritional Biochemistry 

Laboratory does research in several different areas and has published reports of its research in many 

journals, for example the Journal of Nutrition and the Journal of Bone and Mineral Research.

Now, as an example, let’s walk through the first steps of an experiment we 

have done in NASA’s Nutritional Biochemistry Laboratory.

Our Observation

To evaluate a person’s health with respect to a specific nutrient, doctors or scientists will often collect 

blood or urine samples. To evaluate a person’s vitamin D status, we collect blood. We observed lower 

concentrations of certain vitamins, including vitamin D, in blood samples collected from astronauts after 

space flight than in blood samples collected from the same astronauts before flight. As you will learn later 

in this book, vitamins are important and they can do specific jobs in our body. If we don’t have enough of 

any one vitamin, that is, we are deficient in it, we can become very sick. The symptoms of the sickness will 

depend on which vitamin is missing. In general, a balanced diet can help prevent deficiencies. That means 

eating a variety of foods and food types, and even a variety of colors. 

Did you know?

“Deficient” means that you are 

missing something that is necessary.
29

Our Hypothesis

We didn’t know the exact reason why the astronauts’ vitamin D levels were lower after flight, but we 

hypothesized that the crew members were simply not getting enough vitamin D from their food or their 

environment. Our hypothesis was based on several pieces of information, so it wasn’t just a random guess 

but rather an educated guess. We knew that space foods are low in vitamin D. Vitamin D is not present in 

many foods naturally, except for fish such as salmon, and there are not many space food items that contain 

salmon or vitamin D. Also, vitamin D is a unique vitamin because your body can make it when you are 

exposed to the sun. Did you know that children who do not get enough vitamin D, either from exposure to 

sunlight or from their food, can have bowed legs or rickets because vitamin D is important for bone health? 

Getting some (but not too much!) sunlight exposure is important, as is consuming foods that contain 

vitamin D—like fish, milk, yogurt, and fortified cereals. 

Because astronauts are shielded from the sun by their space suits and the International Space Station itself, 

their bodies cannot make any vitamin D while they are in space. So, because their bodies cannot make 

vitamin D, the space food system is low in vitamin D, and their vitamin D status decreases after flight, we 

made an educated guess that the amount of vitamin D that they are currently getting in space is not enough 

to meet their needs. We then performed several experiments to test pills (supplements) containing 

different doses, or amounts, of vitamin D. You will learn more about these experiments in the vitamin D 

chapter later in the book.
30

Conducting experiments during space flight can be tough, especially nutritional biochemistry research. 

Obtaining some of the most basic measurements, even something as simple as measuring body weight, is 

challenging in a weightless environment. In fact, body weight is 

defined by Earth’s gravity. But your body has the same 

mass whether it is on Earth, on the moon, or 

in a weightless environment. We measure 

body mass (but not body weight) during flight 

using very special equipment, called a Space 

Linear Acceleration Mass Measuring Device, or 

SLAMMD, as we like to call it. Below is a depiction 

of one of the astronauts on the SLAMMD, which 

uses some basic math and science (physics) 

principles to determine the crew member’s 

body mass.

Working with fluids in space is difficult as well, 

especially when you are trying to transfer a fluid 

from one container to another. Pouring things is 

impossible (well, everything is possible, but let’s say that pouring things without a major spill is impossible). 

One of the main ways that we determine whether astronauts are healthy in terms of nutrition is to analyze 

blood and urine samples, both of which, as you know, are liquids. They are collected from astronauts before, 

during, and after space flight. 

The techniques used for blood sample collection during space flight are actually very similar to those on the 

ground. A small needle is inserted into a vein, and it is connected to a vacuum tube. The blood is pulled into 

this tube. Once in the tube, the blood usually needs to be processed. During processing the cellular and 

liquid components of the blood are separated from one another so that researchers can conduct tests on 

different parts of the blood.

Space Flight Research
31

Depending on the type of blood collection tube that was used 

(and specifically, what was in the tube) the liquid part of blood 

is called either “serum” or “plasma.” Most often, the blood is 

allowed to clot in the tube, much like when a wound forms a 

scab after you fall and scrape your knee. This produces serum, 

a straw-colored liquid that makes up a little more than half of 

the blood (most of the rest is red blood cells). Serum contains 

water, proteins, vitamins, minerals, salts, sugars, and lipids. 

The specific chemicals in serum provide a good indicator of 

whether or not our body systems are receiving proper nutrition. 

Scientists use a machine known as a centrifuge to separate 

the serum from the blood cells. A centrifuge is kind of like a 

carousel, only it is a smaller version that fits on a lab counter 

and spins much faster, typically rotating about 3000 times 

per minute! The centrifuge holds test tubes of blood in little 

compartments. After 15 to 30 minutes the centrifuge 

is finished spinning and the serum in each test tube is 

separated from the blood cells. Scientists can 

then use the serum to perform various tests. 

Did you know?

Not all astronauts are doctors – in fact, 

most are not medical doctors. Astronauts 

are trained to do medical procedures 

that might be needed in space flight. 

One such procedure is drawing blood for 

the “Nutrition” experiment.

>> Blood makes up about 10% of your 

body weight.
32

In July 2006, a centrifuge was launched on a Space Shuttle to the 

International Space Station (ISS). Having a centrifuge there makes it 

possible to separate blood cells and serum in space. Astronauts can 

collect blood samples from each other and scientists can use these 

samples to see what happens to the human body in space. 

The centrifuge in the ISS is about 12 inches across, relatively small 

compared to the largest centrifuges. In fact, NASA has one centrifuge 

here on Earth that is big enough to spin humans! (See the Artificial 

Gravity section.)

After the blood has been processed, it needs to be frozen, or else the 

chemicals we want to study will start to break down. The freezer in 

your kitchen uses gravity, and special technology had to be developed 

to make freezers work in space. On the ISS, we have a special freezer 

called a MELFI (Minus Eighty Laboratory Freezer for ISS). The lowest 

temperature that the freezer in your house can reach is about –20°C 

(–4°F). What temperature do you think the MELFI might be? Did you 

guess –80°C? This was our initial goal, but the freezer actually works 

better than that, and is usually –96°C. Obviously this freezer is very 

cold, which is important for keeping the chemicals in blood from 

breaking down.

Did you know?

A man by the name of Antonin 

Prandl invented the first centrifuge 

to separate cream from milk.

...Space Flight Research
33

Assessing Nutritional Status

In 2006 we started an experiment called the Nutritional 

Status Assessment Supplemental Medical Objective, or more 

simply the “Nutrition SMO,” or often we just call it “Nutrition.” 

This study was designed to evaluate ISS astronauts’ nutritional 

status during space flight. To do this, we have the astronauts 

collect blood and urine samples throughout the mission. 

After these are brought home, we analyze the samples for 

chemicals that tell us about the crew members’ bones, 

muscles, vitamins, and minerals. This type of testing is called 

“nutritional assessment”— we are checking, or assessing, 

nutrient levels in crew members during 6-month expeditions 

to the ISS. Knowing how nutrient status changes 

during these missions will help us better prepare 

for missions to the moon and Mars. 

While they were in space, astronauts collected 

their blood several times into test tubes. 

The tubes were centrifuged and then frozen in 

the MELFI until they were returned to Earth on 

the Space Shuttle. For the Nutritional Status 

Assessment experiment, we analyzed these 

blood samples to examine the effects of space 

flight on nutrients (vitamins and minerals), bones, 

muscles, and other body systems. 

Did you know?

Thea and her friend Lin are taking a tube of 

blood out of the centrifuge on the ISS.

Nutrition Research
34

Nutrition and Bone

Loss of calcium from bone is a serious concern for astronauts, and nutrition provides a number of potential 

ways to counteract bone loss during space flight, as well as in people on Earth. In 2010, Nutritional 

Biochemistry Laboratory scientists started to investigate, for the first time during space flight, the ability of 

nutrition to lessen bone loss of astronauts. The scientists made a hypothesis that a diet with a lower ratio of 

animal protein to potassium will lead to decreased loss of bone mineral during flight. 

This experiment, called “Pro K” (Pro is short for protein, and K is the chemical abbreviation for potassium), 

will help to determine the nutritional requirements and the type of food systems needed for future exploration 

missions. The information we get from this experiment will also help the bone health of people on Earth, 

because people tend to consume large amounts of animal protein and not enough fruits and vegetables. 

...Nutrition Research

Did you know?

Animal protein (meat and dairy foods) tends to be rich in 

chemicals that produce acid in the body, while foods rich in 

potassium (for example, bananas) tend to have chemicals 

that produce base, which can neutralize the acid.

When the overall effect of the diet 

is acidic, this can lead to bone 

breakdown, and we have seen 

this happen in research subjects 

who stay in bed for a long time.
35

How Stable is that Food?

In another experiment, called the “Stability” experiment, our lab 

investigated the effect of long-term storage on space foods. 

The reason we wanted to investigate this was that foods often 

wait a very long time (months, and even years) from the time they 

are prepared for flight until they are eaten. Foods become stale, or 

sometimes taste funny (or bad) when they are too old, and this taste 

is often caused by vitamins and other nutrients breaking down into 

other chemicals over time. If enough of a nutrient breaks down, then 

the food is no longer providing the nutrients we expected it to provide. 

It is possible that nutrient breakdown happens faster in the space flight 

environment than on Earth.

To test this, we studied nutrient stability in foods after they had been 

in space for days or months at a time. We sent up 4 bags, containing 

different types of space foods, to space on the Space Shuttle. 

The foods in the bags were rich in vitamins and other nutrients that 

we are currently studying at NASA. Items such as salmon, almonds, 

and broccoli with cheese were included. One of these bags was 

brought back home on the same Shuttle, while the other 3 stayed 

on the ISS. Another bag was brought home to Earth after 11 months 

in space, another after 18 months, and another after 29 months 

(more than 2 years!). We measured vitamins and other nutrients in the 

foods that had been in space, and compared the measurements to 

data from identical foods that we stored in the laboratory for the same 

amount of time. 

Did you know?

When you see an expiration date 

on a food purchased at the grocery 

store, it means that after that date, 

the nutrient content or the flavor or 

smell of the food is likely not good 

anymore. 

Eating food that is past the 

expiration date (or older than its 

suggested shelf life) could even 

make you sick, depending on the 

food item.
36

We found that storage on a spacecraft didn’t cause a faster breakdown of the nutrients than storage on 

Earth, but that over time, many of the nutrients do break down. Actually this finding was not too surprising. 

As you know, many foods have expiration dates, which are placed on their packages for you to be aware of, 

for just this reason. What this means, though, is that as we plan exploration missions far from Earth, we need 

to be very sure that the foods to be eaten on those missions have the right nutrients to keep astronauts 

healthy, and that those nutrients will be there at the end of the mission as well as at the beginning!

To help students become aware of the shelf life, or storage stability, of food, we placed several bags 

filled with space food, much like the ones flown on the Space Shuttle and the ISS, in classrooms across 

the nation. The students and teachers then conducted tests on foods similar to those in the packs flown 

in space.

Helpful Link

The results of the students’ testing may be found on the Stability Space Flight Testing blog: 

http://stabilityflightkitstudy.blogspot.com/ 

...Nutrition Research
37

Space vs. on the Ground: What’s an Analog?

An “analog” is something that is similar in some 

ways to something else. Doing research in space 

is very expensive and takes a very long time 

because not many people can be launched into 

space each year. For this reason, we do some of 

our research here on the Earth with analogs of 

space flight. These are called “ground analogs.” 

Some analogs, or models, are better than others.

Bed Rest

One of the most common ground analogs for the effects of space 

flight in humans is bed rest. Men or women volunteer to be research 

“subjects” or participants, and can spend anywhere from a few days 

to several months lying down in bed! During bed rest, your body 

doesn’t use muscles and bones for their usual functions of working 

against gravity and helping you stand up and move around. Bed rest 

subjects are in bed throughout the entire study. They eat and read in 

bed, and even use bed pans to go to the bathroom. They can take 

sponge baths, or if it is available, use an invention that lets a person 

shower while lying down. During bed rest, subjects lose muscle and 

bone just as astronauts do, although the speed of loss is slower 

during bed rest. This is probably because these bed rest 

volunteers still experience gravity while they are in bed, due 

to the fact that they remain on the Earth. Bed rest studies 

help scientists study changes that occur in the human 

body in space, and test ways to counteract these changes. 

Did you know?

Twice in recent years the bed rest 

studies in Galveston, Texas, were 

stopped earlier than planned, and just 

about everything at the NASA Johnson 

Space Center was shut down for several 

days. One time was when the Houston 

area was evacuated for Hurricane Rita, 

and once again when Hurricane Ike hit 

the Texas coast near Galveston. 

>> Tim can’t get up for a shower 

because he is a volunteer for a 90-day 

bed rest ground analog study at NASA. 

In these studies, the subjects are not 

allowed to get up for anything—for a 

full 90 days.

Research in Space vs. on the Ground
38

Ground analog bed rest studies require a great deal of work and many people. 

A lot of teamwork is involved to make sure everything gets done exactly as 

planned. These studies are difficult, but you can study more subjects, and 

collect more data, than is usually possible during real space flight.

The fact that we use bed rest as a way to study changes in bone, muscle, 

and other body systems should show you just how important physical activity 

is for good health. Sitting in front of a TV or computer too long will cause your 

bones and muscles to start breaking down too!

Under the Sea

Imagine your environment was in the ocean, 47 feet below the surface, for 2 

weeks, and you couldn’t come up for air! Several times in recent years 6 crew 

members (including astronauts, other scientists, and “habitat technicians”) 

have done just that. They lived in an underwater habitat called Aquarius off the 

coast of Florida for a week or two. The underwater project is called NEEMO, 

which stands for NASA Extreme Environment Mission Operations. The crews 

who live and work underwater complete many scientific experiments to help 

us figure out what happens to their bodies, and how “aquanauts” perform in 

an environment similar to space flight.

A unique aspect of living in the habitat is that the air pressure 

inside the habitat is increased because it is under water, so 

the aquanauts actually breathe more oxygen in one breath 

than when they are at the surface. In a nutrition experiment, 

we have studied the nutritional status of the aquanauts. 

Specifically we have studied the effects of a high-oxygen 

environment on molecules in the body such as iron, protein, 

DNA, and fats. We can investigate these effects by measuring 

chemicals in the aquanauts’ blood and urine to identify which 

molecules are affected. 

...Research in Space vs. on the Ground

Did you know?

A habitat is a place or 

environment where people 

(or other creatures) can live. 

An aquanaut is a scuba 

diver who can live inside 

and outside an underwater 

habitat for an extended 

period of time.

>> Diego and Lin are working 

outside the NEEMO habitat, 

and Thea and Tim are 

monitoring them from inside 

the underwater habitat. 

Living and working in 

extreme environments is a 

challenge that astronauts 

and aquanauts face. 
39

When the NEEMO crews live in the underwater habitat, they do not always have direct access to medical 

doctors to help with medical problems that might come up. Other scientists have tested the abilities of 

remote-controlled robots to perform medical functions to treat patients and the ability of aquanauts to use 

a computer program that can talk a crew member through the proper steps to treat a medical problem. 

These technologies will be important for the future of NASA, when we go to the moon and Mars! 

The Bottom (or top) of the World!

Antarctica is a good model of space flight for studying 

vitamin D. Vitamin D is a vitamin that your body can produce 

when you are exposed to sunlight. Similar to the situation 

in space flight, people living in Antarctica are not exposed 

to any sunlight for almost 6 months at a time during their 

winter months (February through September).

Each year, more than 800 scientists from all over the world 

journey to different research stations in Antarctica to study 

volcanoes, fish that don’t freeze, fern fossils, stardust, 

ancient bacteria, and more.

Did you know?

98% of Antarctica is covered by a thick layer of 

ice. The average thickness of the ice sheet is 

7,200 feet.

No one country owns Antarctica. The Antarctic 

Treaty, which has been signed by 45 countries, 

reserves that area as a zone for the peaceful 

conduct of research.
40

Artificial Gravity

When leaving Earth’s gravity, the body begins to adapt to a new environment, one where less muscle and 

bone is needed to help a person stand or move around, where the heart doesn’t have to pump as hard to 

get blood to the fingers and toes, and where astronauts can move up and down with a small push-off from 

the spacecraft floor (or wall, or ceiling...). 

To adapt to the new environment, the body changes itself. Some of these changes can be hazardous to the 

health of astronauts during their mission or even after they return to Earth (or land on the moon or Mars), 

where gravity is much greater. One possible way to minimize the effects of gravity on the body is to use 

“artificial gravity.” 

We recently completed a bed rest study in which we created artificial gravity by using a centrifuge, a device 

that spun people in a way that made them feel like they were standing up (even though they were lying down 

at the time). This device has effects much like those of amusement park rides that spin and make you feel 

like you are stuck to the wall. This spinning produces a force that imitates the gravitational pull of the Earth, 

the “force of gravity.” Because the “centrifugal” force produced on the body by the centrifuge isn’t the same 

as gravity, it is called artificial gravity. 

...Research in Space vs. on the Ground

>> Thea and Diego are participating in a 

study in which scientists are testing the 

effects of extra gravity (artificial gravity) on 

bones and muscles. This is a “human-rated” 

centrifuge that spins the subjects around 

while they are lying down. Because they are 

spinning, there are extra gravity loads on 

the body. You can feel artificial gravity if you 

spin around in a circle with your arms out. 

Your hands will start to feel heavier because 

you have put additional centrifugal forces 

on them. 
41

The bed rest experiment had people stay in bed for 21 days and 

split them into two groups, the control and experimental groups. 

Subjects in the experimental group were centrifuged for 1 hour 

every day, but those in the control group were not. We studied 

the bones, muscles, and other body systems of both groups to 

see if the spinning helped to reduce the negative effects of bed 

rest. Although this particular study showed that the centrifuge 

didn’t help bones, it did help muscles and the heart. In future 

studies scientists will try to determine what would help protect 

bones. These studies might include either applying a greater 

centrifugal force, achieved by spinning faster, or having subjects 

exercise while they are rotating. If artificial gravity is effective, 

someday a similar artificial gravity device may be flown in space, 

or we may even spin the spacecraft very carefully to create 

gravity inside for the space explorers.

Did you know?

Most scientific experiments have a 

control group and an experimental group. 

The experimental group is “treated” in 

some way—they may exercise, take a 

pill, or receive some other “treatment.” 

The control group does not receive the 

treatment, and the data collected from 

them are compared with data from the 

experimental group. In the bed rest 

experiment, artificial gravity was the 

experimental condition. We tested 

whether artificial gravity protected 

different body systems by comparing 

data from the experimental group to 

the control group.
42

Around the Globe

We have worked with scientists around the world to do space flight studies and ground-based analog 

studies. We’ve used bed rest to study bone and muscle loss with colleagues in Boston, Massachusetts; 

San Diego, California; Galveston, Texas; Toulouse, France; and Cologne, Germany! Can you point out these 

locations on the map below? We’ve also worked with scientists from Indiana; Gainesville, Florida; and as 

close to home as Houston, Texas; and as far away as British Columbia, Canada; Hamilton, New Zealand; 

Moscow, Russia; and Brisbane, Australia!

Summary

Doing experiments with all of these space analogs gives us a better understanding of the effects of space 

flight on the body. The knowledge gained from experiments performed during space flight and in analog 

conditions will allow astronauts to live and work for the long periods of time that it will take to fly to the moon 

or even farther—to Mars.

...Research in Space vs. on the Ground
43

Space Flight Nutrition

In this Section, Lin, Tim, Thea, and Diego— explore the nutritional requirements of space 

flight. The Space Nutrition Team will help you discover how important each nutrient is to health 

here on Earth and in space flight.

43

Section Three
44

What’s so important about nutrition?

Eating nutritious food is important to help you grow strong muscles and 

bones, and to keep you healthy throughout your life. Like it or not, eating is 

something you really can’t live without, and eating right can help determine 

the quality of your life, whether you are a teen or an astronaut. 

The main job of NASA’s Nutritional Biochemistry Laboratory is to determine how much of each nutrient 

(vitamins, minerals, calories) astronauts need to eat while they are in space. Nutritional Biochemistry 

Laboratory scientists have a set of recommendations for what crew members should eat during space flight, 

and sometimes they change it because of what their research tells them. They also need to check to see if 

astronauts in space are getting enough, or too much or too little, of each nutrient. 

How do we know if the body is getting the right nutrients? Keeping track of what crew members eat tells 

part of what we need to know. We do this with a computerized questionnaire, which the astronauts on the 

International Space Station fill out once a week. Another part of our knowledge comes from collecting blood 

and urine samples before and after flight, and measuring biochemicals in them that tell us how well the 

astronauts are processing each nutrient. The concentration of each vitamin and mineral can be determined, 

and we can measure other biochemicals that tell us about muscle, bone, kidneys, and more! By putting 

together these two parts of our knowledge, we can look at the relationship between what the astronauts ate 

and how well their bodies used each nutrient. Then we can estimate whether they are getting enough, too 

little, or too much of each nutrient.

...Space Flight Nutrition
45

As we study more astronauts, we learn a little more about 

the effects of space flight on the body. Over time, we 

can learn enough to recommend diets that meet needs 

for specific nutrients, and the foods can be modified or 

new foods can be designed so they will provide the right 

balance of nutrients to the crew. It’s easy to see why 

nutrition is as important to you as it is to the astronauts!

Did you know?

Lin is completing her Food Frequency 

Questionnaire. We now know that she likes 

salmon because she ate it three times this week! 

Salmon contains a lot of vitamin D and important 

omega-3 fatty acids that will help protect her 

muscles and bones during space flight.
46

Our bodies need several categories of nutrients. Macronutrients are ones that 

we need a lot of, like fat, protein, and carbohydrate. Vitamins and minerals 

are micronutrients. We don’t need a lot of each one, but they are vital for our 

good health.

Macronutrients

Fat, protein, and carbohydrate provide the energy we need to grow and do things.

Energy (Calories)

Energy is what keeps us going. Every cell in your body needs energy to function properly. The food you eat 

provides energy, which is measured in calories. Balancing the energy you take in from foods you eat with 

the energy your body uses each day is important for good nutrition. Eating enough calories helps make you 

alert and able to do your schoolwork. Without enough calories, you will be tired and your muscles will not 

work well. However, too many calories can also be bad for your overall health. Balancing exercise and good 

nutrition is key to your overall health.

Nutrients

>> Thea and Tim know that eating too many 

calories can lead to gaining weight, and that 

playing basketball can burn calories that are 

not burned while sitting on the couch and 

watching television.
47

A healthy diet should include the right number of calories. 

In addition to the total number of calories, the source of calories 

is important. For a healthy diet, calories should come from the 

following sources: 50 to 60% from carbohydrate (found in foods 

like rice, breads, or pasta), 30% from fat (found in foods like 

whole milk, meat, and nuts), and 10 to 15% from protein (found 

in foods like whole grains, dairy products, beans, and meat). 

Food labels are a great place to learn about your favorite food. 

First, check the serving size and how many servings are in 

that package. Next, look at how many calories are in each 

serving, and what percentage of the calories come from fat, 

carbohydrate, and protein. For more information about the 

number of servings of foods you need each day, check out 

the new guidelines for healthy eating established by the 

United States Department of Agriculture at 

http://www.choosemyplate.gov/.

Did you know?

Fat has more than twice as many calories, 

per unit weight, as carbohydrate and protein.

>> Thea and Diego know that maintaining a 

healthy diet can help them perform better 

in school, give them energy to play with their 

friends, and maintain a healthy body.
48

Vitamin D

Vitamin D is unique in that it can be considered a vitamin or a hormone. A hormone is a biochemical that is 

made in one part of your body and acts on another part. Vitamin D can be synthesized (made) in your skin 

when you are exposed to sunlight. 

If you don’t get enough sun exposure, you need to get vitamin D from the foods you eat. Vitamin D is found 

naturally in fish. Milk and cereals (and some orange juices) are fortified with vitamin D. A fortified food is one 

that has had nutrients added to it. Just read the food nutrition label to find out if the food you eat has any 

added vitamin D. 

Vitamin D is very important for your bones, in part because vitamin D helps your body use the calcium in 

your diet. If you don’t get enough vitamin D, your body will be “deficient” in that vitamin and won’t be able to 

use calcium from food, and your bones will become weak. 

Knowing that vitamin D is synthesized in your skin after exposure to sunlight, you can imagine that getting 

enough vitamin D from the sun would also depend on the time of year and where you live. Do you think 

living in Texas or in Alaska would be better for skin production of vitamin D? Often, people who live in places 

where there is less sunlight have to use artificial light that helps their bodies make vitamin D.

Vitamin D is like many nutrients: although getting too little of it is bad for your health, getting too much can 

also be bad for you. This usually happens only if you take too many vitamins. Luckily, the body won’t get too 

much vitamin D just from sun exposure. However, too much sun can cause health 

problems like sunburn, or even skin cancer.

Vitamins

>> The Space Nutrition crew is enjoying a quick game of 

volleyball in the sunshine, and all the time their skin is making 

vitamin D for strong bones. They also know not to spend more 

time than 5-10 min in the sun without sunscreen because of the 

risks for skin cancer.
49

Remember, astronauts are not exposed to the sun during space flight, 

because the windows of the space vehicle block the specific types of 

rays that help make vitamin D. The foods on board a spacecraft do 

not contain enough vitamin D to make up for the lack of sunlight. 

Even when they are taking extra vitamin D, International Space Station 

crew members often have a lower amount of vitamin D in their blood 

after flight than they did before flight.

NASA’s Nutritional Biochemistry Laboratory scientists are trying to 

find the amount of vitamin D that could be used to prevent vitamin D 

deficiency in astronaut crews. This is very important for astronauts who 

will be in space for long missions on the ISS or even on the moon, and 

it is even more critical for missions to Mars. To study vitamin D and 

the lack of sunlight, we travel literally to the end (or the bottom) of 

the Earth! The amount of sunshine a person in Antarctica receives 

during the winter, which is zero, is similar to the amount in space flight. 

Nutritional Biochemistry Laboratory scientists have performed studies in 

Antarctica to determine how effective different amounts of supplemental 

vitamin D would be in space.

Did you know?

A fortified food is one that has 

had nutrients added. If you look 

at a Food Nutrition Label and 

see vitamins and minerals in the 

ingredients list, this means they 

have been added to the recipe.

Vitamin D deficiency, long thought 

to be rare, is turning up in kids in 

America. Be sure to get enough 

vitamin D in your diet or to get out 

in the sun for short periods!

Milk and orange juice may be 

fortified with vitamin D, meaning 

that vitamin D is added to them. 

This makes them good dietary 

sources of vitamin D.
50

Vitamin K

When you get a cut, the blood eventually stops flowing because a blood clot forms. This process is known 

as “coagulation” (pronounced ko-ag-you-lay-shun). Vitamin K is very important in this process. Vitamin K 

represents just how exciting the field of nutrition can be. We are still learning more about what vitamin K does 

in the body, and how important it is for all of us—even astronauts. 

In addition to its role in blood clotting, vitamin K is very important for bone health. Current research 

indicates that vitamin K helps bones make proteins that hold calcium in place. Some scientists in Europe 

(the Netherlands) have investigated whether vitamin K can help protect against bone loss in astronauts. 

The story of vitamin K has an unusual cast of characters. 

Bacteria...they are a normal part of your digestive tract. Although having bacteria in your intestines may 

sound gross, it is very important, especially when it comes to vitamin K. The bacteria in your large intestine 

actually make vitamin K, some of which can be absorbed and used by your body! 

Rats....dead ones to be exact...and you thought the bacteria part was gross! What do dead rats have to 

do with vitamin K? They are a good example of why vitamin K is 

important. Some types of rat poison are made from a chemical 

called warfarin that blocks the action of vitamin K in the body. 

Rat poison works because the rats eat the poison and end 

up not having enough vitamin K for their blood to clot normally. 

They die from internal bleeding. This helps 

show you just how important 

each vitamin is!

...Vitamins
51

As with most vitamins, the best food sources of 

vitamin K are vegetables. Vitamin K-rich foods are the 

dark green and leafy kinds—like spinach, kale, and 

broccoli. Just a few bites of spinach has all of the 

vitamin K you need in a day (and a lot of other vitamins 

as well). Vegetables are an important part of an 

astronaut’s diet, and of yours. You can eat spinach as 

the green part of your salad, instead of lettuce. Give it a 

try....it worked for Popeye!

Did you know?

Vitamin K is essential for blood clotting. Scientists in 

Copenhagen, Denmark, discovered this and named the 

vitamin for its role in “koagulation.”

Vitamin K is important for both you and animals 

including rats! Chemicals such as warfarin that look 

like vitamin K can actually make vitamin K less 

available in the body, and as a result blood clotting is 

less effective. If too much of the drug is given (as is 

the case with rat poison), the result is that the animal 

dies because its blood cannot clot properly. 

>> Tim’s body will absorb the vitamin K from the 

spinach he is eating. Other nutrients his body will 

absorb from spinach are iron, folate, and vitamin A.
52

Other Vitamins

Every single vitamin is crucial for your body to function. Vitamin K and vitamin D were mentioned above 

because of their role in bone health, but we also need to be very sure that astronauts get enough of all of 

the other vitamins. The other vitamins sometimes have complicated names, like thiamin, riboflavin, niacin, 

vitamins B-6 and B-12, folate, biotin, and pantothenic acid—or they may simply be letters, like vitamins A, 

C, and E. Vitamins A, D, E, and K are fat-soluble vitamins, meaning they dissolve in your body’s stored lipids 

or fats. The other vitamins mentioned are water-soluble, meaning that they are not stored in your body, and 

after they are eaten, may be washed out of your body with other bodily fluids. Missing one single vitamin in 

your diet could be catastrophic to your health. 

An example of the havoc wreaked by missing one vitamin is the fact that millions of sailors died in the 

18th century from a disease called “scurvy.” Scurvy is caused by missing vitamin C in your diet. After this 

catastrophe, many ships carried oranges to alleviate the lack of vitamin C in sailors. Today, many foods are 

fortified with vitamin C, and fresh fruits that supply vitamin C are readily available, but scurvy could still occur 

if these foods are missing from the diet. We learned an important lesson from those early sailors. 

Another example is a disease called “pellagra.” Thousands of deaths occurred from this disease in the early 

1900s before doctors figured out that it was caused by a lack of niacin in the diet. Now, niacin is added to 

many foods you purchase in the grocery store. Read the food nutrition label on foods such as cereal and 

instant oatmeal to find out if you are buying foods with niacin added.

Even though we know about these diseases now and which vitamins we need to include in the space food 

system, we need to make sure that the vitamins remain stable and will still be in the food by the end of a 

3- to 5-year trip to Mars. Stability studies done during space flight and on Earth have provided (and will 

continue to provide) valuable data to determine the shelf life of nutrients in the food system.

...Vitamins
53

Calcium (and Bones!)

Calcium (kal-see-um) is a mineral our bones need to grow 

and be strong. Calcium is found in many of the foods and 

beverages we eat and drink. Did you know that milk, broccoli 

with cheese, and pizza are loaded with calcium? If we don’t 

eat enough calcium, our bones become weak. Healthy bones 

have millions of tiny holes in them that are part of the bones’ 

framework or structure that helps make them strong and 

keep our bodies standing up. The part of the bone that has 

these holes is called “cortical bone.” Without calcium, the 

tiny holes start to become larger. This can cause the bone 

to become very brittle, and can lead to a disease called 

“osteoporosis” (os-tee-oh-por-oh-sis). Although osteoporosis 

usually occurs in older people, not getting enough calcium 

can be bad for anyone! Calcium is needed for other things 

besides bones. We need calcium for strong muscles, healthy 

blood, and healthy teeth and gums. How much calcium 

do we need? People 9 to 13 years old need to eat 1,300 

milligrams (mg) of calcium each day. For young people 

9 to 13 years old, your percent daily value (% DV) 

numbers for all the foods you eat in a day 

should add up to at least 130% DV for 

calcium each day.

Did you know?

People with osteoporosis have extremely weak 

bones that can be very painful. They have to 

be careful because they could break a bone 

just by falling down.

>> Tim may need to include more foods with 

calcium in his diet. What else can he do to 

develop strong bones? One way astronauts 

keep strong bones during space flight is to 

do “resistive” exercise, such as using a muscle 

or a machine or device to resist the force of 

another muscle. Participating in activities like 

playing hopscotch and jumping rope can help 

make your bones strong.

Minerals
54

Reduced gravity (microgravity) in space produces less 

pressure on your bones because you are not using them to 

hold your body up against the gravitational force of Earth. 

This causes them to not be as strong as they are on Earth. 

Astronauts lose bone during space flight. Simply eating 

more calcium is not going to help their bone loss because 

their body’s ability to absorb calcium is decreased during 

space flight. 

Scientists are researching ways to provide astronauts with 

the right amount of calcium that will keep their bodies healthy 

when we send them on exploration missions.

Iron (and Blood!)

Iron is a very important mineral that has many functions in 

your body. Iron works with proteins in the body to produce 

energy from fat and carbohydrate in your diet. In fact, if you 

don’t eat enough iron, you will get tired more easily and you 

may not be as alert during school. 

Iron is also important for transporting oxygen in blood to all 

of your tissues and organs. Iron is stored in erythrocytes 

(uh-rith-row-sites), the red blood cells. About two-thirds 

of the iron in the body is stored in erythrocytes. The rest 

circulates through the blood bound to another protein, called 

transferrin, and some iron is stored in tissues. Many proteins 

in cells use iron for important cellular processes. 

...Minerals

Did you know?

A milligram (mil-li-gram) is a measurement 

of the amount of a mineral in the food you 

eat. If you look for calcium on a food nutrition 

label you will not see it listed in milligrams. 

Instead, you will see it listed as the percent 

of daily value (% DV). The % DV listed on a 

food label is the one for adults For young 

people 9-13 years old, your % DV numbers 

for all the foods you eat in a day should add 

up to at least 130% DV each day for calcium.

Almost 99% of the calcium in our bodies is 

found in our bones.

Vitamin D helps the body absorb calcium 

from the diet.

Women have to really watch their calcium 

intake because they are more likely to 

develop osteoporosis than men.
55

Erythrocytes act like a delivery truck full of oxygen that delivers 

oxygen to the areas in the body that need it. Iron deficiency 

can happen because of a lack of iron in the diet, or excessive 

bleeding. The disease that is the result of a severe iron deficiency 

is called anemia.

Iron-deficiency anemia impairs brain development in infants and 

kids. Although iron deficiency can be reversed by adding more 

iron to the diet, scientists are not sure whether the effects on 

the brain can be reversed. So... it’s important to include iron-rich 

foods in your diet, such as meat, eggs, dried fruits, pumpkin, 

and fish.

Did you know?

>> Can you tell the difference between 

Lin and Diego? Which student had 

iron-fortified cereal for breakfast? 

What types of foods do you eat that 

contain iron? Iron is found in meat, 

eggs, dried fruits, pumpkin, fish, and 

iron-fortified cereals. If you read the 

food nutrition label, you will find the iron 

content of the foods you are eating. 

>> Where are these oxygen molecules 

headed? What does the truck 

represent? What mineral helps 

get oxygen to the areas in your body 

that need it?
56

Space flight has many effects on the body, and the iron and 

blood changes are some of the most unique. Astronauts have 

fewer blood cells during space flight, but this does not seem to 

be related to not getting enough iron in their diets. In fact, we are 

concerned that astronauts might get too much iron during space 

flight. This is the opposite of concerns for people on Earth, where 

too often people don’t get enough iron in their diets. This is very 

important, especially for growing kids.

...Minerals

Did you know?

The iron in red blood cells is what gives 

blood its red color.

Vitamin C increases your body’s ability 

to absorb iron from the diet. So...next 

time you eat some oatmeal or cereal, 

put some strawberry slices on top to 

increase your absorption of iron!

>> Tim is pumping iron. Is this the same 

kind of iron that is found in the foods 

you eat to maintain your good health?
57

Radiation

Everything around us is made up of very small particles called 

atoms, which are constantly moving. The atoms in an object can be 

packed very close together or be relatively far away from each other. 

This packing determines which state the “matter” of an object is in—

solid, liquid, or gas. Solids have atoms that are very close together; 

an example is a rock. Liquids have atoms that are also close together, 

so they are also hard to compress. Gases have atoms that move freely, 

and in fact the atoms try to spread themselves out. Some atoms in 

solids, liquids, or gases aren’t as “calm” as others. These “nervous” 

atoms are unstable, and when moving around, they give off energy. 

We call this energy “radiation.” As they move, the atoms try to become 

calm again, or become stable. 

Believe it or not, we are surrounded by 

radiation all the time. Radiation comes from 

outer space, the sun, the Earth, and even 

from our own bodies! Radiation can also 

come from cellular phones, televisions, 

microwaves, glow-in-the-dark watches, 

high-voltage power lines (these are lines 

that distribute electricity to your home), and 

many other items. Radiation can be very 

helpful to us—it can be used to fuel power 

plants, to produce medical x-rays, or to 

treat cancer. 

Did you know?

Just as length is measured in a 

unit called a meter, radiation is 

measured in a unit called a rem. 

One-thousandth of a rem is 

called a millirem (similar to how 

one- thousandth of a meter is 

called a millimeter).

Most Americans are exposed to 

about 360 millirem of radiation 

per year. Check out http://www.

epa.gov/radtown/enter-radtown.html 

to learn about your exposure 

to radiation.

UV radiation from the sun can be 

beneficial, as when sunlight makes 

plants grow, or harmful, as when 

overexposure to the sun’s rays 

causes sunburn.

>> Sometimes, in a visit to the doctor 

or hospital, we may find that we 

need to have an x-ray. This helps the 

doctor to look inside our body and 

help heal what might be wrong.

Antioxidants, Radiation, and Oxygen
58

Too much radiation exposure can be bad for our health 

and for the environment. The radiation given off by the sun 

can be quite dangerous to humans on Earth when they 

are exposed to too much sun. In space, the astronauts 

are outside the protection of the Earth’s atmosphere, so 

they are exposed to more radiation than we are here on 

Earth. Astronauts wear spacesuits that protect them from 

many dangers in space, one being radiation. During space 

walks, astronauts must wear face shields in their helmets 

to protect themselves from the large amount of ultraviolet 

(UV) radiation. UV radiation can cause damage to the skin, 

commonly known as sunburn. On Earth, the ozone layer 

and lower atmosphere help to protect us from some of the 

UV radiation given off by the sun. Some of the UV light filters 

through the atmosphere and still reaches us here on Earth, 

which is why we protect ourselves with sunglasses and 

sunscreen with sun protection factor (SPF) 15 or higher.

...Antioxidants, Radiation, and Oxygen

Did you know?

Energy produced by the sun has many different 

wavelengths, and only a few of them are visible. 

Ultraviolet light cannot be seen by humans, but 

it can damage your skin. Prolonged exposure can 

wrinkle skin after many years, or skin cancer 

may form.

SPF (sun protection factor) is a number on a 

scale of 2-100, and describes a product’s ability 

to block out the sun’s burning rays.

>> The Space Nutrition Newsletter team members 

want to stop the free- radical thief from taking 

their body’s vitamin E. Eating a diet rich in 

antioxidants, such as foods containing vitamin C, 

is a good way to stop free radicals from forming.
59

Oxygen Damage (Oxidation)

Have you ever wondered why an apple turns brown after being 

cut? The brown color is caused by a process called oxidation 

(ox-ih-day-shun). Oxidation happens when oxygen molecules 

react with other molecules such as protein or fat, and damage 

their structure. Just as apples can be damaged, our bodies can 

also be damaged by oxidation. Why is oxidation a bad thing? 

The process of oxidation produces molecules called free radicals 

that can damage cells in our body. A free radical acts sort of like 

a thief. It is a molecule that is missing an electron, and therefore 

steals electrons from healthy (normal) molecules. Years of exposure 

to free radicals may cause serious health problems, such as cancer 

or heart disease. 

Oxidation in our bodies can be caused by environmental factors 

such as exposure to air pollution and cigarette smoke, and 

overexposure to sunlight. 

How do we stop oxidation? Antioxidants are substances that 

slow or stop oxidation in our bodies. If you sprinkle a cut apple 

with orange juice, then it will not turn brown. This is due to the 

fact that orange juice and all citrus fruits are a great source of 

antioxidants, such as vitamin C. Natural foods with a lot of color 

are usually good sources of antioxidants. Here are a few that 

can be found in the diet: beta-carotene (mangos, carrots), zinc 

(milk, nuts, shellfish), vitamin C (oranges, strawberries), flavonoids 

(green tea, apples), vitamin E (avocados, nuts, seeds), and 

selenium (seafood, lean meats).

Did you know?

The number of food components that act 

as antioxidants is greater than 4000.

A good source of the antioxidants called 

polyphenols is dark chocolate.

Space flight exposes astronauts to 

oxidation from the sun’s radiation and 

from high concentrations of oxygen in the 

atmosphere of the spacecraft and the 

EVA suit.
60

Summary

Many nutrients are required by our bodies. Some provide energy, like protein, carbohydrate, and fat. 

Others, like vitamins and minerals, carry out important activities to help in almost every aspect of your 

body’s daily chores. Knowing some of these details might help you understand why a balanced diet is 

critical, to make sure you have all of the nutrients you need to keep you healthy. Too little, or often too 

much, of any single nutrient can cause health problems. Balance is the key!

...Antioxidants, Radiation, and Oxygen

>> The foods you eat at every meal should 

include antioxidants. Look at what you are 

eating. Do the colors of your foods look 

like a rainbow? A variety of colors at every 

meal are a good indication that you are 

getting enough antioxidants.
61

Being Healthy is Not Just about Nutrition 

(Even Though We Like to Think it is)

The Nutritional Biochemistry Lab is part of a larger group of research laboratories working to understand 

the changes in the human body as it gets used to weightlessness.

Section Four
62

Exercise Lab

Exercise affects almost all systems of the human body, in people on Earth as well as in astronauts during 

space flight. Exercise is one of the most common means of trying to counteract, or reverse, the negative 

effects of space flight on the heart, blood vessels, muscle, and bone. The Exercise Physiology Laboratory 

at the Johnson Space Center is a team of scientists and engineers who are trying to understand the effects 

of microgravity (weightlessness) on human performance (or fitness), and to develop exercises to help keep 

astronauts healthy during and after their missions. The Exercise Team at NASA builds exercise equipment 

that will work without gravity, and does tests to be sure that the exercises that crew members do in 

reduced-gravity environments will help keep them healthy.

Exercise and nutrition are important components of a healthy lifestyle, whether you live on the ISS or here 

on Earth. Developing good eating and exercise habits when you are young will help you keep healthy as you 

get older. 

What you do when you are 10 to 20 years old can have big 

effects on how healthy (or sick) you are when you get older. 

Bone is a great example of this. If you eat and exercise 

right through your teen (and pre-teen) years, you’ll be 

less likely to get osteoporosis when you are older. 

Osteoporosis is a disease that makes the bones get very 

weak and brittle, and break easily. It is usually thought of 

as a disease of the elderly, but prevention of this disease is 

best started in the first 10 to 15 years of your life!

...Being Healthy

>> Lin is riding her bicycle. She rides it at least 3 times a 

week to make sure her bones, muscles, and heart remain 

healthy. What exercises do you do each week to stay 

healthy? Do you have physical education class in school? 

What else can you do to keep your body healthy?
63

Different types of exercises can help different parts of the body. Aerobic exercises, like running on a treadmill 

or riding on a bicycle, can help to keep your muscles from losing strength and help to keep changes from 

occurring in your heart and your blood circulation. Weight lifting, a form of what is called “resistive exercise,” 

can also help to keep you from losing bone strength.

Cardiovascular Lab

The circulatory or cardiovascular system is made up of the heart, blood vessels, and blood. The blood 

vessels that carry blood away from the heart are called arteries, and those carrying blood to the heart are 

called veins.

Many changes occur in the cardiovascular system during space flight. The heart does not have to work 

against Earth’s gravity to supply blood and oxygen to the body. Not having to work so hard can weaken 

the heart muscle and can reduce its ability to provide blood and oxygen to the brain when the astronauts 

return to Earth. This can cause light-headedness and reduce the astronauts’ ability to walk or exercise. 

The Cardiovascular Laboratory at the Johnson Space Center is a team of scientists and engineers who are 

trying to understand the changes in the cardiovascular system that are caused by microgravity and find ways 

to improve the astronauts’ ability to adapt to these changes, both during and after space flight.

Neurosciences Lab

Have you ever spun yourself around to make yourself dizzy? The nervous system (nerves, brain, eyes, 

and inner ear) is affected when you spin around. This system is also affected by lack of gravity. 

The Neurosciences Laboratory at the Johnson Space Center investigates the effects of space flight on 

the nervous system. “Neuro” comes from “neuron,” the Greek word for nerve. “Neuron” is also an English 

word for nerve cell. The nervous system controls all actions of the muscles, including those that result in 

movements of the eyes, head, and body. Scientists and engineers in the Neurosciences Laboratory measure 

changes in what the eyes see, what the brain tells the muscles to do, and how the muscles respond to this 

information before and after space flight.
64

The Neurosciences Laboratory also studies the effects of space flight on 

the neurovestibular system (NVS), the nerves and organs that keep the 

body in its proper orientation. The inner ear is a very important part of the 

NVS. Organs in the inner ear help us to keep our balance by telling the 

brain about the motion and position of the body. Without gravity, the NVS 

needs to readapt, and the brain has a hard time figuring out which way is 

up. Scientists and engineers work together to develop training programs to 

help the NVS so that astronauts can stay in space longer.

Behavior and Performance Lab

Do you think you could share your classroom with 2 of your closest 

friends for 6 months, 24 hours a day, away from everyone else you know? 

Would you be homesick? Would you worry about your family? Would you 

get tired of working in the same room with your friends every day? 

The members of the Behavior and Performance Lab try to understand 

what the astronauts will experience emotionally while they are in space. 

They work with other medical team members to determine the stresses 

involved with each mission into space, such as differences between crew 

members, the isolation of being in space, and the work required of the crew 

during their mission. Scientists develop techniques that help astronauts 

deal with the stress of being away from home and working with the same 

people every day (all day) for weeks to months at a time. Some of the 

techniques that astronauts are encouraged to use are making phone and 

video calls to family members, and participating in a hobby during the 

flight (activities like playing the guitar, reading books, or watching movies). 

Exercise is another great way to help reduce stress, and it helps your 

muscles too!

>> Tim is dizzy from spinning 

around and then standing up. 

This is the same type of effect 

that reduced gravity has on 

the neurovestibular system. 

Tim is dizzy because the fluid 

in his ears has been affected 

by his movement as he travels 

in circles.

...Being Healthy
65

The Shuttle and International Space Station fly in what we call “low Earth 

orbit,” meaning that they are about 100 to 150 miles from the Earth’s surface. 

In the big picture, there’s a lot more out there to explore.

The moon was our first stop, and that was about a 3-day trip. NASA is starting to look outward even farther, 

and is contemplating someday going off to check out an asteroid, and then perhaps going on to Mars. 

Given the technology we have today, and the nature of travel to other planets, a trip to Mars is expected 

to take about 6 months for travel to get there, about 18 months for a stay on the planet surface, and then 

about another 6 months to get back. In total, this is about 30 months, or 21⁄2 years. This is a much bigger 

challenge than our current missions (which were by no means “easy”). Imagine how much food you would 

eat in 21⁄2 years, or how much water you would drink. These are just two of the issues that we in nutrition 

think about now. Future exploration will require planners to consider even more—everything from clothes to 

oxygen to exercise will have to be very carefully planned. There’s no store or restaurant along the way where 

you can pick up anything you forget. These will be difficult missions, but they represent the next major leap in 

human exploration. 

>> Our Space Nutrition team—Lin, Tim, Thea, and Diego—have 

enjoyed sharing their space adventures and look forward to learning 

about the challenges and exciting opportunities that future space 

exploration will bring.

The Next Frontier—Exploration
66

adaptation – the process of adjusting to the environment or to specific conditions (in space flight, 

adaptation is the process of adjusting to the lack of gravity and being in a closed environment).

airlock – an air-tight chamber or room that allows passage to or from the vacuum of space. 

On the International Space Station, the airlock module is named “Quest.”

Apollo – in ancient Greek mythology, the name of a god. In space flight the Apollo missions were a series of 

manned and unmanned space flights to and from the moon.

aquanaut – an underwater explorer. In the U.S. space program, aquanauts are the research subjects 

participating in studies in an underwater habitat.

astronaut – a space explorer. In space flight this is the name given to U.S. space explorers; the Russian 

counterparts of astronauts are called cosmonauts.

bed rest – a type of study often used to simulate weightlessness and evaluate effects on the body. 

biochemistry – the chemistry of living matter.

blood serum – the clear yellow liquid that can be separated from blood cells when whole blood clots. 

Blood serum is tested to understand what is happening to the human body before, during, and after 

space flight.

coagulation – formation of a blood clot.

Columbia – poetic name for the USA. In the U.S. space program Columbia was the first Space Shuttle 

orbiter to orbit and return to Earth. On February 1, 2003, the Space Shuttle Columbia disintegrated over 

Texas during its return to the Earth’s atmosphere, resulting in the death of all seven crew members.

Glossary
67

convection oven – an oven equipped with a circulating fan that intensifies the amount of heat in the oven 

and decreases the normal cooking time. In space flight a convection oven is used to reheat food in the 

kitchen area of the spacecraft.

cosmonaut – a space explorer in the Russian space program. (Space explorers from the U.S. and other 

nations are called astronauts.)

deficit – a lack or shortage.

docking or docked – attaching or attached to a site such as a pier. In space flight this is the joining of one 

space vehicle with another or with a space station in space.

EVA – extravehicular activity. In space flight, this is the term for space walks. EVAs are used to repair or 

construct parts of the space vehicle.

Gemini – in astronomy, a constellation (the Twins); it is used in astrology for people born between May 21 

and June 20. In space flight, Gemini was a U.S. program in the 1960s, in which two-person space vehicles 

were flown to prepare for the Apollo moon landings.

habitat – a place or environment where people (or other creatures) can live. 

International Space Station – a giant environment for living and working that orbits the Earth once every 

90 minutes. The ISS was built in sections called “modules” that were taken to space either in the Space 

Shuttles or on Russian launch vehicles.

medical monitoring – the measurement of physiological data before, during, and after space flight to 

ensure optimal astronaut health.

Mercury – the United States’ first space program in which humans were sent to space. Mercury astronauts 

were launched into space on either a Redstone or Atlas rocket, depending on how far they traveled.
68

MERLIN – the Microgravity Experiment Research Locker/Incubator, a small refrigerator/freezer for the ISS.

mid-deck – one of the 2 levels (flight deck and mid-deck) of the crew compartment on the Space Shuttle 

orbiter. The mid-deck is “downstairs,” and is where most experiments are conducted, where the “kitchen” is, 

and where the bathroom is.

Mir – the first Russian space station.

Mission Control Center – the center that controls activities of space flight, or dive activities for the 

NEEMO program.

muscle atrophy – a process by which muscles weaken during space flight.

NEEMO – NASA Extreme Environment Mission Operations. These missions are conducted in an underwater 

habitat off the coast of Florida on the bottom of the ocean (about 50 feet below the surface).

neuroscience – the science of studying the nervous system. The Neuroscience Laboratory at NASA’s 

Johnson Space Center studies changes in what the eyes see, what the brain tells the muscles to do, and 

how the muscles respond to this information before and after space flight.

Neutral Buoyancy Laboratory – a giant swimming pool for diving that allows astronauts to train for space 

missions involving space walks.

nutritional biochemistry – the study of how nutrients in food affect how our bodies work. Every cell in your 

body requires many different vitamins and minerals as well as energy to keep you alive and healthy.

nutrients – energy (carbohydrates, fats, proteins), vitamins, and minerals that are needed for growth and 

development and that are required from the environment.

...Glossary
69

NVS – the neurovestibular system, which includes the nerves and organs that keep the body in its proper 

orientation. The inner ear is a very important part of the NVS.

orbit – the path an object takes around another object. The Shuttle and International Space Station orbit the 

Earth, and they do this once every 90 minutes.

orbiter – a vehicle that can travel around the Earth. There are some sub-orbital vehicles that can provide 

seconds to minutes of weightlessness, but they do not travel around the Earth. Six Space Shuttle orbiters 

were built: Enterprise (never flown in space, was used for testing landings), Columbia, Challenger, Discovery, 

Atlantis, and Endeavour. 

osteoporosis – a disease that makes the bones get very weak and brittle, and break easily.

planetary travel – travel between planets, such as Earth and Mars.

Progress cargo vehicle – an unmanned Russian resupply vehicle that delivers supplies or food to the ISS. 

There are 3-4 Progress flights per year. It does not return to Earth – instead, it is packed with waste and used 

goods from the ISS and burns up upon reentry into the Earth’s atmosphere.

rehydratable – a food that is dehydrated, meaning all of the water has been taken out. Water can be added 

back to the food to rehydrate it before it is consumed.

solar – relating to the sun.

shelf-stable – refers to a food item that is not likely to spoil for at least 6 to 12 months.

Space Shuttle – a NASA reusable launch vehicle that included an orbiter capable of orbital flights. The first 

Shuttle launched in 1981 and the last Shuttle mission flew in 2011. 

space flight – travel through outer space.
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space walk – NASA calls space walks “extravehicular activity” (EVA). It is a very important part of many 

space missions. When astronauts need to go outside the Space Shuttle or International Space Station, they 

have to put on a special suit that acts like a personal spacecraft. The EVA suit provides pure oxygen for 

the astronauts to breathe, and is cooled with a special suit underneath that can have cool water circulating 

throughout it. During an EVA, astronauts can be in these suits for up to 10 hours.

SPF – sun protection factor. The SPF number is listed on sunscreen containers to let you know how much 

ultraviolet radiation can reach your skin. The higher the number, the more protection the sunscreen provides.

Stability – a study conducted by the Nutritional Biochemistry Laboratory to determine the effects of 

long-duration space flight on nutrients in space foods. Foods can become stale, or sometimes taste funny 

(or bad) when they are too old, and this taste is often caused by vitamins and other nutrients breaking down 

into other chemicals over time. If enough of a nutrient breaks down, then the food is no longer providing the 

nutrients we expected it to provide.

thermostabilized – heated to very high temperatures to destroy bacteria and then packaged in cans or 

closed pouches. Examples of thermostabilized foods are canned ravioli and soups. 

ultraviolet (UV) radiation – a type of radiation from the sun that can cause damage to the skin, commonly 

known as sunburn. On Earth, the ozone layer and lower atmosphere help to protect us from some of the UV 

radiation given off by the sun. Some of the UV light filters through the atmosphere and still reaches us here 

on Earth, which is why we protect ourselves with sunglasses and sunscreen with sun protection factor (SPF) 

15 or higher.

...Glossary
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Science Content Standards K – 12

Unifying Concepts and Processes - As a result of activities in grades K-12, all students should develop 

understanding and abilities aligned with the following concepts and processes:

» Systems, order, and organization

» Evidence, models, and explanation

» Constancy, chance, and measurement

» Evolution and equilibrium

» Form and function

Content Standard A - Science as Inquiry:

Grades 5-8:

» Abilities necessary to do scientific inquiry

» Understandings about scientific inquiry

Content Standard B - Physical Science:

Grades 5-8:

» Properties and changes of properties in matter

» Motions and forces

» Transfer of energy

Content Standard C - Life Science:

Grades 5-8:

» Structure and function in living systems

» Reproduction and heredity

» Regulation and behavior

» Populations and ecosystems

» Diversity and adaptations of organisms

National Science Education Standards
72

Content Standard D - Earth and Space Science:

Grades 5-8

» Structure of the Earth system

» Earth’s history

» Earth in the solar system

Content Standard E - Science and Technology:

Grades 5-8

» Abilities of technological design

» Understandings about science and technology

Content Standard F - Science in Personal and Social Perspectives:

Grades 5-8

» Personal health

» Populations, resources, and environments

» Natural hazards

» Risks and benefits

» Science and technology in society

Content Standard G - History and Nature of Science:

Grades 5-8

» Science as a human endeavor

» Nature of science

» History of science

Adapted from National Science Education Standards, © Copyright 1996 by the National Academy of Sciences.

...National Science Education Standards
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Space Nutrition Book 

Educator Guide

Some strategies for teaching and learning using Space Nutrition are listed 

below. Some strategies are used before reading to prime students and get 

them ready to learn, other strategies are useful in processing the information 

given the reader. Lastly, some strategies help students hold on to the learning 

by reflecting and retaining the information.1

Getting Reay to Learn: Priming

A Taxonomy of Words for Space Nutrition: Rothstein, E. & Lauber, G. E. (2007). Writing As Learning.

Second Edition. Thousand Oaks, CA: Corwin Press.

» Begin by folding a sheet of notebook paper into two columns by using a “hot dog“-style fold. 

» Use the letters A-M and N-Z to identify each category for your words, skipping lines between letters.

» Build your Taxonomy of Words for Space Nutrition by adding new words to the list before, during, and 

after reading, using each letter of the alphabet as a category heading.

» Display the words on a classroom Taxonomy of Words for Space Nutrtition drawn on large chart paper.

» Use the words for quick reference when writing about, discussing, or working with The Space Nutrition 

Newsletter: The Book.
74

Anticipation Guide: Nessel, D. D. & Graham, J. M. (2007). Thinking Strategies for Student Achievement: 

Improving Learning Across the Curriculum K-12. Second Edition. Thousand Oaks, CA: Corwin Press.

» Create a set of questions from a portion of Space Nutrition on specific points you want to emphasize. 

» Make sure the questions can be agreed/disagreed with by the learners. 

» Make no more than 5 questions.

» Present the questions to the class. Ask them to quietly agree or disagree with the questions.

» Ask tables of students to discuss their answers, using facts to defend their choices.

» Read the selected portion of the text.

» Again, present the questions to the class. Ask them to quietly rethink their former decision.

» Ask tables of students to discuss their answers, and defend their choices. If they have changed their 

answers, ask them to explain why.

Key Word Prediction: Nessel, D. D. & Graham, J. M. (2007). Thinking Strategies for Student Achievement: 

Improving Learning Across the Curriculum K-12. Second Edition. Thousand Oaks, CA: Corwin Press.

» Choose a topic from Space Nutrition.

» Choose 8-15 words from The Space Flight Glossary that coincide with the chosen topic.

» Display the words and the topic for the students to view.

» Have students predict the relationship of the words to the topic.

» Have students read the designated portion of The Space Nutrition Newsletter: The Book.

» Students then discuss the relationship of the words to the topic based on their reading. 

» Were their predictions correct?

List, Group, Label: Nessel, D. D. & Graham, J. M. (2007). Thinking Strategies for Student Achievement: 

Improving Learning Across the Curriculum K-12. Second Edition. Thousand Oaks, CA: Corwin Press.

» Choose a specific set of vocabulary words from Space Nutrition.

» Have tables of students group the vocabulary words, using whatever method they choose.

» Extend the activity by having students label the groups of words. 

» Have groups of students discuss why they chose each label.
75

Unpacking the Meaning: Processing

Key Word Notes: Nessel, D. D. & Graham, J. M. (2007). Thinking Strategies for Student Achievement: 

Improving Learning Across the Curriculum K-12. Second Edition. Thousand Oaks, CA: Corwin Press.

» Chunk a portion of text from Space Nutrition into 4 sections. Each section should be able to be 

completely read in about 2 minutes.

» Each student should design a layout for Key Word Notes on their paper as follows:

» Have each student read the chunked text labeled section one, and take notes from their reading in box 

1 of the Key Word Notes, using 3-5 words that resonate with them from the text. 

» After a specified time limit, have the students stop and discuss what they read with other students at 

their table, using the notes from box 1. 

Key Word Notes for (topic here)

1.

3.

Summary:

2.

4.
76

» Begin reading again with section two, taking notes in the box labeled 2 and stopping after a specified 

time to discuss your notes with your table. 

» Continue onto sections 3 and 4. 

» After the text is read, put it away.

» Without looking at the text, have students summarize their reading in the summary box on the Key 

Word Notes. 

» Have students share their summaries with their table.

» Display the Key Word Notes pages for the class to read and share.

Holding onto the Learning: 

Retaining for Mastery

Assessing student knowledge acquisition using strategies other than formal testing:

» Flow Map: from David Hyerle’s “Thinking Maps,“ 2007, Thinking Maps, Inc.

» Using sequencing, formulate a flow map to show the progression of human space flight.

» Design a flow map to show the steps of the scientific method. Where would you place each of the 

steps of the experiments provided in The Space Nutrition Newsletter: The Book on the flow map?

» Again, a taxonomy of words can be used as an assessment of learning, and so can words that have 

been internalized during discussion.

» Squared Away2: What are you squared away on? What is still rolling around in your head? What will you 

make a point of doing?

» Develop projects from this publication. Have the students conduct a Gallery Walk2 and give affirmations.

» Devise studies based on the scientific method, such as the lemonade study. Have student groups 

display the study they developed.

» Develop a radio show based on nutrition and space. Deliver it to your school in the morning 

anouncements each morning. Written scripts can be displayed.

» Conduct lessons for children in previous grades on nutrition, space, and how nutrition affects their 

performance in school. Display the lesson plans.

» Put on a play for your school that includes skits, songs, and dances based on the book. Let groups 

choose topics based on their interests and strengths. Display the scripts, along with pictures from 

the dramatization. 
77

Some questions for reflection: from Dr. Yvette Jackson‘s “The Pedagogy of Confidence: Inspiring High 

Intellectual Performance in Urban Schools,“ March 2011, Teacher’s College Press.

» What else does this remind you of?

» Where else have you heard this information?

» Where else might you use this information?

» How can you apply this space research to your life?

» What type of pattern do you see between food intake and exercise, and physical health?

» How would you feel about what you read if you were an astronaut?

Some ways to use this book:

» Good health and nutrition studies

» Exercise precursor

» Interdisciplinary studies in health, physical education, and science standards 

Extra activities:

» Make an antioxidant fruit salad: 

http://www.nasa.gov/centers/johnson/slsd/about/divisions/hacd/education/kz_facts.html

» Understanding the science behind radiation levels:

http://www.epa.gov/radtown/enter-radtown.html

» Food planning and ideas for nutrition for specific audiences: 

http://www.choosemyplate.gov/

For more information on education and NASA please visit www.nasa.gov. 

1

From the National Urban Alliance for Effective Education Pedagogical Flow Map. © Copyright NUA, 2009, all rights reserved. 

2

From the National Urban Alliance for Effective Education. © Copyright NUA, 2009, all rights reserved. 
78

About the Authors

Scott M. Smith

Dr. Smith has been a member of the NASA Nutritional Biochemistry Laboratory team since 1992. 

The primary goal of this group is to determine the nutritional requirements for extended-duration space 

flight. This involves conducting both operational and research activities. Operational activities include the 

assessment of nutritional status of crew members on missions to the International Space Station. Dr. Smith 

has been the principal investigator for experiments on International Space Station missions, Space Shuttle 

missions, and joint U.S./Russian missions to the Mir Space Station. He has also led many ground-based 

research projects, including studies of vitamin D supplementation in the Antarctic and extended-duration 

bed rest studies. He is co-author of dozens of scientific publications, including the book Nutritional 

Biochemistry of Space Flight, available via open access at: https://www.novapublishers.com/catalog/

product_info.php?products_id=20061 

Dr. Smith participated in the definition of the current nutritional recommendations for extended-duration space 

flight, and is Co-Chair of the Multilateral Medical Operations Panel - Nutrition Working Group, which includes 

representatives of the 5 ISS partner space agencies: Canada, Europe, Japan, Russia, and the U.S. Dr. Smith 

has served on the Editorial Board of the Journal of Nutrition. He is a member of the American Society for 

Nutrition, the American Physiological Society, and the International Academy of Astronautics.

Dr. Smith received a B.S. in biology and a Ph.D. in nutrition, both from Pennsylvania State University. After 

completing a postdoctoral fellowship in North Dakota, he moved to Houston in 1992 to work at the Johnson 

Space Center.

Janis Davis-Street

Dr. Davis-Street is the Associate Manager of Health and Productivity in Chevron’s Corporate Health and 

Medical department. The Health and Productivity group provides targeted interventions for identified health 

risks and designs health education and health promotion programming for employees, with a focus on 

prevention of injury and disease. Key focus areas include a global cardiovascular health program, onsite 

fitness centers, and prevention of office-based repetitive stress injuries.
79

Dr. Davis-Street has served as a member of the National Business Group on Health’s (NBGOH) Racial/Ethnic 

Health Disparities Advisory Board and is a current member of NBGOH’s Global Health Benefits Institute. 

She obtained her M.S. in nutrition from the University of Alberta and her Ed.D. in health education from the 

University of Houston. Before working at Chevron, she spent 15+ years as a nutritionist at the Johnson 

Space Center, where for much of her tenure she partnered with Dr. Smith and others to support K-12 

education outreach efforts. At JSC, Dr. Davis-Street was involved in nutrition research on International Space 

Station missions, Space Shuttle missions, and joint U.S./Russian missions to the Mir Space Station. She also 

participated in the experiment design and evaluation of several ground-based research projects, including 

extended-duration bed rest studies and exercise countermeasure protocols.

Dr. Davis-Street is a Certified Health Educator Specialist whose interests include corporate wellness, health 

and productivity, health disparities, and the roles of nutrition and exercise in preventing chronic diseases such 

as osteoporosis, cardiovascular disease, diabetes, cancer, and obesity. She has co-authored more than 20 

peer-reviewed scientific papers in the areas of nutrition and space flight.

Lisa Neasbitt

Ms. Neasbitt is a Science Consultant for AUSSIE Professional Development in Manhattan, New York; a 

Mentor for the National Urban Alliance in Syosset, New York, and a Data Consultant for the College Summit 

working with Bill and Melinda Gates Foundation to encourage a college bound culture for seniors in high 

schools across the nation. 

Supporting NASA education, Ms. Neasbitt designed elementary and middle-school science, technology, 

engineering, and mathematics educational materials concerning the U.S. Vision for Space Exploration. 

Before she joined the NASA education team, Ms. Neasbitt’s previous work experience included science 

and technology facilitation in public schools; internal facilitation for Federal Teaching and Learning Grant 

recipients; curriculum correlation for textbook publishers; and curriculum development, publication, and 

instruction for the Michael Dell Children’s Museum. Lisa has been the recipient of many local, regional, state, 

and national science education distinctions. She was nominated by her students for Educator Astronaut, and 

was an Educator Astronaut applicant. 
80

Having science curriculum and instruction experience totaling over 20 years, Ms. Neasbitt holds a B.S. from 

Texas A&M University, and has conducted graduate studies at the University of Houston, the University 

of Houston − Clear Lake, and Texas A&M University. She holds a lifetime Texas teaching certification 

in elementary and science education. A member of the Association for Supervisory and Curriculum 

Development, the National Science Teachers Association, and the National Association for Bilingual 

Educators, she has presented educational materials published with NASA in over 75 workshops nationally 

and internationally. 

Ms. Neasbitt served on Houston Mayor Bill White’s Wellness Council, representing the NASA Johnson 

Space Center Human Research Program Education and Outreach Project. She initiated and sustained 

NASA partnerships with the Houston Independent School District and major league sports teams including 

the Houston Dynamo, the LA Galaxy, and the DC United, as well as government agencies including the 

Food and Drug Administration, Health and Human Services including The Surgeon General, The President’s 

Council on Physical Fitness and Sports, and the United States Department of Agriculture.

Sara R. Zwart

As a member of the Nutritional Biochemistry Laboratory at the Johnson Space Center, Dr. Zwart has been 

involved with research investigating relationships between nutrition and physiological effects of space 

flight, including bone and muscle loss, changes in iron metabolism, and oxidative damage. The Nutritional 

Biochemistry Laboratory is charged with defining the nutritional requirements for extended-duration space 

flight. Operational and research activities are being conducted to define the impact of space flight on human 

physiology and nutritional requirements. 

Space flight studies include nutritional assessments during long-duration space flight and modification of the 

diet to help prevent bone loss associated with space flight. Ground-based research is used to understand 

the role of nutrition in ground-analog studies that simulate varied aspects of space travel. These include 

rotating cell culture models, NASA Extreme Environment Mission Operations (NEEMO) undersea missions, 

extravehicular activity analogs at the Neutral Buoyancy Laboratory at the Johnson Space Center, bed rest, 

and Antarctic winter. 
81

Dr. Zwart earned her Bachelor of Science degree in biological sciences from the University of Notre Dame 

in 1999, and her doctorate in nutritional sciences from the University of Florida in 2003. She joined the 

Nutritional Biochemistry Laboratory at NASA’s Johnson Space Center in 2003 as a National Research 

Council Post-doctoral Fellow, and then began as Research Scientist in the laboratory in 2005. She is now 

Senior Scientist and Deputy Manager for Nutritional Biochemistry. 

About the Illustrator, Marco Zambetti

Currently a Creative Director at Tietronix Software, Inc., an information technology company, Marco Zambetti 

is involved in the art production for serious games and interactive applications, as well as promotional and 

informational material.

Originally from Italy, in 1979 Mr. Zambetti moved to the United States where, after a period of doing odd 

jobs as an illustrator and portrait artist, he landed a position as a graphic designer at a large computer 

manufacturer. There, from the summer of 1984 to the fall of 1988, he produced numerous computergenerated graphics and animated videos. In 1988 he accepted a position as a staff artist/animator at NASA’s 

Johnson Space Center, where he produced videos aimed at informing and educating the public on the 

activities and goals of the space program.

Mr. Zambetti attended the University of Milan department of physics (1974-1975), the Los Angeles Trade 

Technical College commercial art department (1982-1984), Boston University department of computer 

science (1985-1986), and the University of Houston − Clear Lake (2006-2011). He has a Bachelor of Arts in 

applied visual arts and a Master of Science in mathematics. 

Acknowledgments

The authors and illustrator are indebted to many who have helped with this project, and with providing 

a better understanding the role of nutrition and space flight. We thank Jane Krauhs for her outstanding 

editing on this project, and Cory Duke, who lent her outstanding graphics talent to the book. Our illustrator 

recognizes and thanks Anna Glanton, Angelica Zambetti, and Alexandra Zambetti for their assistance 

with inking and coloring of the images herein. Finally, we thank NASA‘s Human Research Program, and 

specifically the Human Health and Countermeasures Element, along with the Human Adaptation and 

Countermeasures Division, for their support of this endeavor.
82