Adventures of the Agronauts

 
 

Content Background

This section provides you with a printable version of the same content that your students will be learning during each Mission. Instructional graphics are included as well. If you need additional review on the content material for a particular Mission, the web resources provided for each Mission are a good place to start. And, feel free to email us with any content questions at agronauts@ncsu.edu.

Printable versions of each of the six Missions are available to download in either Word or pdf format.

Mission 1 (Word) (pdf)
Mission 2 (Word) (pdf)
Mission 3 (Word) (pdf)
Mission 4 (Word) (pdf)
Mission 5 (Word) (pdf)
Mission 6 (Word) (pdf)

For a printable version of all the glossary terms and definitions, please click here.

Mission 1
Mission 2
Mission 3
Mission 4
Mission 5
Mission 6

Mission 1

We need to learn more about how the Sun, Moon and Earth are alike and different so we can make the best decisions about how to grow plants on the Moon. You will find out how they relate to one another and report back on what you've learned to Commander Spud Goodroot.

Sun and Stars
The Moon
Earth Dances
Moon Dances
Moon Visits

Sun and Stars

The Sun is the brightest object in our sky and the largest object in our solar system. The Sun is actually a star that is 93 million miles (that's 150 million kilometers) from the Earth. The Sun is about 4.5 billion years old and is one of more than 100 billion stars in our galaxy. Our galaxy is called the Milky Way Galaxy.

The Earth and eight other planets move around the Sun in paths called orbits. Lighter objects orbit heavier ones, and the Sun is the heaviest object in the solar system. The Sun is more than 300,000 times heavier than Earth.

The Sun is very large compared to Earth. The diameter of the Sun is 100 times larger than Earth! And, even at that size, it is just a medium-sized star compared to others.

The Sun is very hot! The temperature of the surface of the Sun is about 11,000 ºF (degrees Fahrenheit). That's the same as 6093 °C (degrees Celsius). We will learn about temperature scales in another Mission.

The Sun is a ball of gas made mostly of two gasses: hydrogen and helium. The Sun is always working to change hydrogen to helium. The Sun makes the light that we see and the heat that we feel.

The Sun is one of many stars in our galaxy. Other stars in the sky are much further away from us than the Sun. Their long distance away from us is the reason they look like tiny points of light in the night sky.

We measure the distance of stars from Earth in light years. A light year is the distance that light travels in one year. Since light travels at a speed of 186,000 miles/second (300,000 kilometers/second), a star that is one light year away is actually 5.8 trillion miles (9.5 trillion kilometers) from us! The Sun is only 8 light minutes away. The closest star to us other than the Sun is Alpha Centauri, and it is 4 light years away. The most distant stars we can still see without a telescope are about 1000 light years away!

All the stars we see at night from Earth are also stars in our Milky Way Galaxy. There are over 100 billion stars in our Galaxy, but on an average dark night we can only see about 1000 to 1500 of them! Stars produce light and heat by changing hydrogen into helium, just like the Sun (remember, the Sun is a star, too!)

Constellations are patterns of stars in the sky that have names. Constellations can be used to help us figure out where we are on Earth compared to other objects in the sky. Constellations have been used for many years to help sailors navigate in the ocean and also to remember stories about heroes and myths. We see different constellations during different seasons as the Earth moves around the Sun.

The Moon

The Moon is the second brightest object in the sky after the Sun, but it is not a star. The Moon is about ¼ the diameter of the Earth and is made of rocky material. Most lunar rocks are between 3 and 4.6 billion years old. Many scientists believe that the Moon formed when the Earth ran into a very large object (perhaps as big as the planet Mars.) They think the Moon formed from the broken material. The Moon is the only natural satellite of the Earth and travels around the Earth in an orbit. The Moon orbits the Earth because it is so much lighter than our planet.

The Moon is about 240,000 miles (386,000 kilometers) away from Earth. The temperature on the Moon is much colder, but strangely also much hotter than on Earth. It can get as hot as 212 °F (100 °C) and as cold as -233 °F (-147 °C)! This large temperature range happens because the Moon has no atmosphere. On Earth, our atmosphere helps to control the temperature on our planet. Since the Moon has no atmosphere to help with temperature control, it is very hot where the Sun shines on the Moon and it is very cold where the Sun does not shine on the Moon! Because of the way the Moon rotates, the lunar South Pole never gets any sunlight.

Man-made satellites that have traveled around the Moon have found some evidence of ice scattered in some of the deep craters near the Moon's North and South Poles. This means that there is a form of water on the Moon.

Earth Dances

The Earth revolves around the Sun every 365 days, and this is why our calendar has 365 days in a year. That means the Earth, on its orbital path, moves completely around the Sun one time each year. So why does the Earth orbit the Sun? The motion happens because of something called gravity. Gravity is a force of attraction between two objects that have mass. The object with more mass pulls things towards it. Since the Sun has much more mass than the Earth, the Earth is pulled toward the Sun. Gravity is the same force that pulls us to the Earth and keeps our feet on the ground.

If the Sun is pulling the planets, why don't they just fall into the Sun and burn up? Well, in addition to falling toward the Sun, the Earth and the other planets are also moving sideways. Without that sideways motion, Earth would fall to the center; and without the pull toward the center, Earth would go flying off in a straight line. The two forces work together to create an orbital path.

The Earth also has an axis, and it rotates on its axis every 24 hours. This is why there are 24 hours in a day. Revolution is when the Earth moves in a circle around the Sun, and rotation is when the Earth spins on its axis. Because the Earth rotates one time every 24 hours, at any point in a day, half of the Earth is facing the Sun and half of the Earth is facing away from the Sun. In North America, we have daytime when our continent is facing the Sun. North America has nighttime when our continent is on the side of Earth facing away from the Sun. So, when it is nighttime in North America, it is daytime in places on the other side of the Earth.

If we stood in the same spot outside for an entire day, it would look like the Sun was moving across the sky. It is really the Earth that is moving! As the Earth rotates toward the Sun, we see a sunrise, and as it rotates away, we see a sunset. The Sun appears to be directly above us in the sky at noon.

So, we know that the Earth's rotation causes day and night. The Earth's revolution around the Sun also causes our seasons. The different seasons on Earth are caused by two things: the tilt of the Earth's axis and the angle of the sunlight when it hits the Earth.

The Earth is not positioned straight up and down - it is tilted at an angle. The closer the Earth is to the Sun, the warmer it will be. So, for example, when the Earth is tipped towards the Sun, the northern hemisphere has summer. Summer in the northern hemisphere brings longer days (over 12 hours of sunlight a day!) and shorter nights. The sunlight during the summer is also hitting the Earth head on, which heats that part of the Earth. At the same time of the year, the southern hemisphere is having winter, which means less hours of daylight. The sunlight is not striking the southern hemisphere head on at that time, which causes less heating of the Earth in the southern hemisphere.

Moon Dances

We just learned that when one half of the Earth is lit up by the Sun, the other half of the Earth is dark. The same thing happens with the Moon. When the Moon is orbiting around the Earth, we see different parts of the Moon at different times. This makes the Moon seem to disappear slowly and then reappear. There are eight phases of the Moon, and the Moon cycles through all eight phases every 29 1/2 days. This is almost once a month.

Phase 1
New Moon
Phase 5
Full Moon
Phase 2
Waxing Crescent Moon
Phase 6
Waning Gibbous Moon
Phase 3
First Quarter Moon
Phase 7
Last Quarter Moon
Phase 4
Waxing Gibbous Moon
Phase 8
Waning Crescent Moon


What about gravity on the Moon? Gravity helps to keep the Earth orbiting around the Sun. In the same way, gravity helps to keep the Moon orbiting around the Earth. Remember, smaller objects orbit larger ones. The Moon is smaller than Earth, so the pull of gravity from the Earth is stronger. Does the Moon have gravity? Could objects be attracted or pulled towards the Moon by its gravity? Yes, but the gravity on the Moon is only 1/6 of that on the Earth. So, on the Moon, you would only weigh 1/6 of your weight on Earth.

Moon Visits

When a satellite or spacecraft circles close to Earth, we say it is in Low Earth Orbit (LEO). Because these satellites and spacecraft are traveling so close to Earth, they must travel at very high speeds so that Earth's gravity does not pull them back into the atmosphere. Satellites and spacecraft in LEO can circle the entire Earth in about 90 minutes! This high-speed travel creates a state of free-fall, and things in free-fall are said to be "weightless". This state is also called microgravity environment. In microgravity, people do not feel the effects of gravity. This is the reason we see pictures of astronauts floating around on spacecraft. There is no gravity to keep them firmly grounded.

The Moon was first visited by a Russian spacecraft called Luna II in 1959. The first time humans visited the Moon was on July 20, 1969 when Neil Armstrong was the first person to step onto the Moon. The last time anyone visited the Moon was in December 1972.

The Moon is the only extraterrestrial body that humans have visited. Many people want to go back to the Moon, and other people want to go to planets such as Mars or to other objects in the galaxy such as asteroids.

Mission 2

So now we know more about the Moon's environment. Since our goal is to grow plants on the Moon, we need to learn more about plants and how they grow on Earth. Then, we will start to put the information together!

Plant Parts
Making New Plants
Plants and Gravity

Plant Parts

In this section, we will learn the parts of plants. Plants have roots that support the plant and hold it in place. Roots also take in nutrients and water from the soil. The stem acts as a highway to move water and nutrients from the roots to other parts of the plant. Plants are called herbaceous or woody based on their stems. Herbaceous plants have soft stems that usually die back to the ground during the winter. Woody plants are tough and their stems do not die back to the ground.

Nutrients and water travel from the stems to the leaves. The leaves then use the water and nutrients along with sunlight to make food. The food is sent to other parts of the plant. The process in which plants make food is called photosynthesis. In photosynthesis, the leaves use carbon dioxide from the air, nutrients, water, sunlight, and a substance called chlorophyll to make their food, which is called glucose. The process of photosynthesis releases oxygen into the air. Did you notice that in order to make food, the plants use carbon dioxide? Humans breathe out carbon dioxide when we exhale. Then, when the plants are making food, they give off oxygen. Humans inhale oxygen and need it to live.

Leaves can come in many different shapes and sizes. They are designed to catch light and have many openings called stomata that let air and water come and go. You can only see stomata using a microscope. Leaves are covered with a waxy coating called a cuticle that protects them.

Making New Plants

When we think about how to grow new plants, most of us think of planting seeds. Each seed is really a tiny plant in a package. Seeds are protected by a seed coat that can be thick or thin. Seeds have all of the materials inside of them that they need to form leaves, stems, and roots. But, seeds stay dormant until the conditions are right for them to begin to grow, usually warm and wet. Germination is when a root and a shoot begin to grow out from the seed. This is the beginning of a new plant!

There are many things that can go wrong to cause poor germination. If a plant gets too much water, then it might not have enough oxygen to grow. Also, very dry conditions might mean that the plant cannot get enough water to germinate. If seeds are planted too far in the ground, they might use up all their energy before they can get to the sunlight.

Some plants have flowers. Flowers are not only pretty to look at, but they also help the plant make seeds. Flowers can be made up of different parts, but there are some parts that all flowers have. Sepals are the green petal-like parts at the bottom of the flower. Sepals help protect the flower buds. The main flower parts are the male part called the stamen and the female part called the pistil. The stamen is made of anthers and filaments. The anthers carry the pollen and are generally yellow in color. Anthers are held up by the filaments, a thread-like part.

The pistil is made of a stigma, a style, and an ovary. The stigma is the sticky surface at the top of the pistil that traps and holds the pollen. The style is tube-like and holds up the stigma. The style leads down to the ovary that holds the ovules. When pollination happens, pollen moves from the male parts to the female parts. Pollen grains land on the stigma. Then, a tiny tube grows from it and down the style into the ovary. The ovule then becomes the seed and the ovary becomes the fruit.

Pollen moves from the male to female plant parts with the help of insects, the wind, and animals. Since flowers can't move, they need to get pollinators to come to them some other way. That is one reason why flowers are bright colors and smell good. Flowers may be built so that wind is able to pollinate them or so that pollen can stick to the hair of animals as they pass by the flowers. Bees, butterflies, insects, and birds like the bright petals and sweet nectar of flowers. Some flowers open at special times for pollinators, such as plants that open at night and are pollinated by bats.



Some plants do not have flowers. Plants such as ferns, mosses and mushrooms make spores instead of seeds. Ferns make their spores under their leaves. They look like brown spots on the bottom of the leaves.

There are still other ways to grow a new plant! A bulb is a tiny packaged-plant that has everything necessary to grow a new plant. Bulbs have carbohydrates to feed the plant and places for the roots to start growing. Everything is wrapped up very neatly in a tunic. The tunic protects the bulb from drying out. Inside the bulb are scale leaves. They are baby leaves that hold stored food for the bulb.

Other ways to grow new plants are with tubers and cuttings. A tuber is a fat stem that grows underground and is used for food storage for plants. A cutting is a piece of a plant's stem, root, or leaf that is planted and grows roots.

Plants and Gravity

So, do plants grow the same way in space as they do on Earth? Scientists are learning more about how plants grow in space every day. Gravity plays an important part in plant growth. Remember when we learned in Mission 1 about gravity, the force of attraction that keeps our feet firmly planted on the Earth? We know which way is down because of gravity's pull on us. Well, plants also use gravity to know which way is down. The root tips of plants have special starch grains inside called statoliths. These grains are heavy. They fall to the bottom of the root tip cells and act as a signal. They tell the plant which way is down. If you tip a plant on its side, the heavy grains in the root tip would again be pulled down by gravity, and this would tell the plant which way is down. The root would then start growing in that direction.

In the same way that roots use gravity signals to grow downward, shoots use these signals to grow upward. These plant movements are called gravitropism. Scientists want to understand the signals inside a plant that help the shoots to know to grow up and the roots to know to grow down. In spaceflight, where the plant does not have gravity to help the roots and shoots to orient, plants usually get confused and grow in a mixed-up way. In a microgravity environment, the starch grains should float around randomly, just like astronauts do. Instead, scientists have found that they bunch together. Why? It's part of the mystery. Maybe one day you will help to solve it!

Mission 3

We have learned about the Moon's environment and about the parts of plants. In this mission we will begin to learn what it takes to keep plants alive. Plants need seven important things in order to grow, and the next two missions are about these seven things. We will compare the Moon environment to the Earth environment. Does the Moon have all of the same conditions as Earth? If not, what do we need to think about to make sure the plants can grow on the Moon?

Soil and Plants
Soil on the Earth
Soil on the Moon
To Soil or not to Soil…

Soil and Plants

Plants and humans need three of the same things to live: air, water, and nutrients. The soil on Earth plays an important role in getting water and nutrients to the roots of plants. The soil also allows air movement around the roots. Remember, the roots take in water and nutrients from the soil and move them into the plant. Soil has other important roles, too. Soil keeps the roots of plants secure and supports plants so they can grow well. Some types of food that we eat everyday are even grown completely under the soil! Potatoes, radishes, and carrots grow and develop in the soil itself.

Soil on the Earth

The soil on Earth is made up of four main things. Rock particles broken down by wind and water make up the largest part of soil on Earth. Soil also contains water and air. Lastly, soil is made up of organic materials. Humus is among the richest and darkest of soils and develops from decaying plant and animal life. Humus is generally very dark and is a good fertilizer because of the nutrients contained in the decaying plants and animals. Humus can hold and release water and nutrients as needed. It also improves the soil so that air can move in the soil. It is crumbly instead of sandy, like a beach or clumpy like clay.

Soil can be described in terms of its texture. Texture refers to how much sand, silt, and clay is in the soil. Sand is the largest of these soil particles. Sand is very rough and does not hold nutrients that plants need to grow very well.

Silt is a medium-sized soil particle that feels smooth to the touch. Silt can hold a lot of water, and water moves easily through it. Large amounts of silt can be found where rivers empty into lakes because silt is washed downstream by rivers. Clay is the smallest or finest particle in soil. Clay is smooth and can hold many nutrients, but water and air do not move through clay very well.

Loam is soil that has the best mixture of clay, sand and humus for growing plants. In trying to get the right balance of nutrients, many people make their own organic material and add it to the soil. It is called compost. Composting is the natural breakdown of plants and other once-living materials. As the materials die and break down they release nutrients for other plants to use. Composting happens in nature when leaves on the forest floor decay and pass their nutrients on to the soil, but humans can also make compost. To make a compost pile, you add the right combination of dead leaves, lawn clippings, and food scraps. The compost pile must be stirred once in awhile so that air can help the material to decay. Tiny creatures called microorganisms, such as bacteria and fungi, break down the organic matter, and heat is produced when this happens. When a compost pile is working well, it can get very hot in the middle!

Soil on the Moon

Now that we know more about soil on Earth, what about soil on the Moon? There are two types of terrain on the Moon: areas filled with craters (called the highlands) and smooth areas (called the maria). Craters are bowl-shaped marks on the Moon's surface that were made after the Moon was hit by large objects, such as meteors. The maria are craters that were flooded and filled with molten lava. The surface of the moon is mostly covered with regolith, a mixture of fine dust and rocky debris made by meteor impacts. Regolith can be called the "soil" of the Moon. The look and feel of regolith is different from place to place on the Moon and is deeper in some places than in others.

What about Moon rocks? The rocks of the Moon were formed when lava cooled and hardened many years ago. How are rocks on the Moon different than on Earth? Remember, the Moon has no atmosphere or weather. So rocks on the Moon are not eroded by wind, water, or ice.

To Soil or not to Soil…

Do plants really need to have soil in order to get water, air and nutrients? Maybe not. Many new vegetable farms are using a system to grow plants called hydroponics. In hydroponics, plants can get some things they need to live without the use of soil. The plant food in a hydroponic garden is given to the plants by mixing natural fertilizers in water to make a 'nutrient solution'. The plant roots may be put on a block or tube that allows air to flow around the roots. In aeroponics the roots are constantly sprayed with a nutrient-rich solution.

Mission 4

Commander Spud Goodroot is very excited about the information you will learn on Mission 4. We will continue our investigation into the 7 things that plants need to live. We have talked about water, nutrients, and air. Now we will talk about the remaining four things that plants need to grow.

Light
Me and My Shadow
Why Plants are Green
Heat
Time
Room to Grow

Light

As we learned in Mission 1, energy travels to Earth from the Sun in the form of light and heat. We learned in Mission 2 that plants use sunlight to make the food it needs through the process of photosynthesis. So, plants need light in order to live.

What happens when light from the Sun hits an object? Some objects are transparent, like glass, and the light travels through them easily. Some objects like paper are translucent. This means that light does travel through but the path of the light is distorted. And, some objects are opaque. Light does not travel through these objects.

Me and My Shadow

A shadow is an area where light cannot directly shine because an opaque object lies between the area and the Sun or source of light. A shadow is also the image cast by an object that is blocking rays of light.

Sometimes we can see very special, unique events in the sky when the Sun, Moon and Earth line up in a certain way. An eclipse is a shadow cast by one large object on another. A solar eclipse occurs when the Moon passes directly in front of the Sun and casts its shadow on the Earth in the middle of the day. In a lunar eclipse, the Moon passes through the Earth's shadow. During a full moon, when a lunar eclipse occurs, you can see the Earth's shadow move over the moon.


Why Plants are Green

Light can be refracted, absorbed, or reflected by an object. Refraction happens when a light ray traveling through air hits a different material. When the light ray hits the new material, its speed and direction will change. This can cause some things to look strange. For example, this happens if we look at a pencil through a glass of water.

The color that we see when we look at an object is the colors of light that the object reflects. Objects that are white are reflecting all of the colors of the spectrum and absorbing none. Objects that are black are absorbing all colors of the spectrum and reflect none. So what does that mean about all of the other colors we see? For example, when we look at Polly in a dark room with a flashlight, she appears to be red in color. Polly and other strawberries reflect red light and absorb the other colors of the spectrum.

If we put a blue light bulb in our flashlight and shine that blue light on Polly in a dark room, what color do you think she will be?

Polly will appear black. When you shine only blue light on Polly, there is no red light for her to reflect. So she appears to have "lost" her color. You can try this at home with apples and bananas using colored cellophane paper and a flashlight.

So now we know why plants appear to be green. They are reflecting green light and absorbing the other colors of light. When we try to grow plants in space, this information can be useful for scientists. Spacecraft are not hooked up to power stations and they cannot pull up to a gas station either. Spacecraft like the space shuttle have a limited amount of energy. If we need to run lights to grow plants on these spacecraft, that takes energy. But we may be able to reduce that amount of energy by only providing the plants one or two colors of light instead of all colors.

Did you know that plants can also move? They usually do so by growing in a certain direction, towards light, water, gravity or even away from other plants. These movements and responses are called tropisms. Phototropism is when plants grow towards the light. Remember in Mission 2 when we learned about plants responding to gravity, or gravitropism?

Heat

Heat is another form of energy that comes from the Sun and is needed by plants to live. But, be careful…too much heat will kill plants! Plants generally like the same temperatures as humans. Temperature is a measurement of the amount of heat in or around an object. There are several temperature scales that measure heat in degrees. In North America, we typically use the Farenheit temperature scale when we talk about our local weather. Scientists in all countries use the Celsius temperature scale.

We have learned that light energy moves - its waves travel and can be reflected and bounce off of objects. Heat energy moves as well, and it moves in three different ways. Conduction is when heat is transferred from an area of high temperature to an area of cooler temperature by the movement of energy between the particles that make up those materials. When you put your hand against a cold window on a winter's day, the window sucks the heat from your hand by conduction. Another example is when a metal pot is on a hot stovetop. At first, only the bottom of the pot directly touching the stovetop is very hot. Then, the heat energy moves through the metal particles that make up the pot. Eventually the entire pot, and sometimes even the handle, becomes hot. This is conduction of heat through a material.

Convection occurs when a fluid, such as air or water, comes in contact with an object that is at a higher temperature. Have you ever looked at a hot cup of cocoa where the liquid meets the air? You begin to see circulation or swirled patterns appear. This circular pattern happens when the air near the surface of the cocoa gets warmed by the coffee and it rises. The surrounding cooler air falls to take its place and begins a circular motion. This convection pattern will continue until the two substances reach the same temperature.

Many weather patterns in the troposphere occur because of convection. Sea breezes are a good example. During the day, the land warms up faster than the sea. The air above the ground is hot, the air above the water is cold. The hot air above the land rises, and the cold air above the sea swoops in to take its place. This causes a wind to blow from the ocean toward the land, a sea breeze. At night, the situation reverses. The land cools down faster than the sea, so the air above the ground is colder than the air above the water. The hot air above the water rises, the cold air from the land rushes in, and you have a land breeze.

The third way that heat energy moves in through radiation, energy carried from the Sun to us by electromagnetic waves. To scientists, radiation means any kind of light ray, whether visible or invisible (like ultraviolet or infrared light). Hot things glow and give off light which carries the heat away, and that is just how the Sun heats the Earth. Radiation can be harmful in high amounts, and solar radiation is largely absorbed by the stratosphere, a layer of the Earth's atmosphere. The ozone layer is located in the stratosphere.

One neat thing about light and heat energy is that they can be changed into one another. Light from the sun can also warm our bodies when we are standing outside in the sunlight. And, heat from a fireplace also provides light in the flames.

Time

There are two more things that plants need to live and grow which may seem pretty obvious to us. One of those things is time. Plants live, grow, flower, and die in different time frames. Annuals are plants that complete their life cycles in one growing season. Biennials need two growing seasons to complete their life cycles. A perennial is a plant that lives for three of more years. It may grow new stems if it is herbaceous, or it may just live for many years (trees.)

Room to Grow

And last but not least, plants must also have room to grow both above and below ground so they can carry out the process of making food for themselves. If plants do not have enough room to grow, they begin to compete with each other for resources like nutrients and water. The stronger plants will take the nutrients and the other plants will wither and die.

Mission 5

We know about the Moon's environment. We know about plants and what they need to grow on Earth. Now, we want to send people and plants up to the Moon to grow and live. We will learn about what happens to both people and plants in the space environment and use that information to make decisions about which plants to take to the Moon.

People in Space
Plants in Space
Crop Talk

People in Space

On Earth, people need some of the same things that plants need in order to live and grow: air, water, food, and the right temperature. In space, a microgravity environment, people still need these same things to live but they may not be as available as they are on Earth. People who train to go into space are called astronauts. Astronauts have special suits that provide these things in the space environment.

Astronauts experience a changes in their body systems while in space. One change is a fluid shift. On Earth, our heart pumps blood up to our brain and then Earth's gravity pulls the blood back down. But in space there is no force pulling the blood back down. This causes a cephalad fluid shift, which is also called "puffy face syndrome." The extra fluid will make the face swell and become puffy. In addition to puffy faces, astronauts also get "chicken leg syndrome." This happens because the fluid is not being pulled down toward the legs, and their legs seem to shrink. The fluid shift can cause some feelings of congestion, but most astronauts adapt to this in a few days and then feel fine.

A joke that some people tell about space travel is, "There is not much space in space!" What this means is that there is not a lot of room on spacecraft for things or for people. Astronauts who go into space on the space shuttle live in an area about the size of a school bus. And, there are usually 6-7 astronauts on board for each trip into space. Some trips are very short, two weeks or less. But, in order to set up a habitat for humans to live on the Moon or on another planet like Mars, astronauts would have to travel and stay in space for a much longer period of time. For example, just to get to Mars, it could take almost 9 months! Can you imagine traveling non-stop on a school bus with six other people for 9 months?

Scientists on Earth want to know about what happens to living things in space. So, while astronauts are in space, they perform many experiments for scientists on small animals like mice, fish, microorganisms, and yes - on plants! And, all astronauts are experiments themselves. They keep details of their activities and monitor their physical fitness as well as other things so that we better understand what happens to people in space.

Plants in Space

You already know that plants provide people with many things we need: air, clean water, food, medicines and fibers. If we are ever going to colonize on another planet or the Moon, we will need to have plants with us. But how would we take them? Let's think about the challenges of growing plants in space.

Remember that one of the things plants need to live is room both above and below ground to grow so they can carry out the process of making food for themselves. Based on what you have learned about the limited amount of room on a spacecraft, do you think that astronauts could launch with or grow stalks of corn, which can be 7 feet (2 meters) high? Probably not! Scientists have developed some dwarf varieties of plants such as wheat, tomatoes and rice that are just as nutritious as normal varieties on Earth and will only grow to about 12 inches (25 centimeters) in height.

The other factor that would prevent us from taking off and launching with large-sized plants is weight. It is very expensive to launch a lot of weight into space. As a matter of fact, a $2 burger on Earth would cost you almost $3500 in space! That's because it currently costs $22,500 to launch one kilogram (or $10,000 per pound) into space. Instead of launching thousands of burgers for a long trip into space, astronauts and scientists are learning how to grow food for longer trips.

We have also learned about composting, which is a very important idea for scientists who are studying how to grow plants in space. Remember, there is not much room in space. That means there is not much room for scraps and trash, either. The great thing about plants is that they can be turned into compost and used over and over to replenish the nutrients in the soil. This practice would help cut down on the waste in space!

Last but not least, plants provide other benefits to the astronaut crew. They are in space for a long time, and it helps them to stay happy and excited about their work when they are able to see something green and growing. Can you imagine not seeing grass, trees or plants for months, or even years?

Crop Talk

In this section, students select three crops they might want to take to the Moon and research some of their characteristics.

You are going to investigate the following things about the plants you selected and record your findings in the table you created. There are several places that can help you determine the answers you need about your plants. Your teacher can help you find resources on the internet. Here are a couple:

USDA Nutrients List for Common Foods
http://www.nal.usda.gov/fnic/foodcomp
Data/SR15/wtrank/wt_rank.html

NC Cooperative Extension - Resources on Crops
http://www.ces.ncsu.edu/resources/crops/

Whole Foods Market Fruit and Vegetable Nutrition Info
http://wholefoodsmarket.com/healthinfo/list_library.html

Space Food and Nutrition
http://spacelink.nasa.gov/products/Space.Food.
and.Nutrition/

Watch your Garden Grow - University of Illinois Extension
http://www.urbanext.uiuc.edu/veggies/index.html

You can also ask people who work with plants, like farmers or horticulturalists at a plant nursery. Many times, packets of seeds can be found in grocery stores and home supply stores. These packets often will have information about how to grow the plant and the characteristics of a fully grown plant.

1. Size - How tall are the plants you selected when they are fully grown? How large is the plant in circumference?

When we are thinking about which crops to grow on the Moon, size is an important issue to consider. If we wanted to grow pine trees, our plant growth chamber would have to be very large! And, we would have to launch the spac