Mission 5: Living Things in Space

Mission 5 – page 1

Name: ______Teacher: ______

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.

Sections:

People in Space Bones and Muscles Human Bodies 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 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 need to stay in their space craft or have special suits that provide these things in the space environment. Mission 5 – page 2

Astronauts experience 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 Mission 5 – page 3

Mars, it could take almost 6 months! Can you imagine traveling non-stop on a school bus with six other people for 6 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 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 so that we better understand what happens to people in space. Mission 5 – page 4

Bones and Muscles

Spaceflight can have an effect on two important systems in the human body: the skeletal system and the muscular system. Put these together and it is called the musculoskeletal (mus cue low skel eh tuhl) system. Bones and muscles work together to help us stand and situp, move, and keep us warm.

The skeletal system is made up of the 206 bones in the human skeleton. Bones have many important functions for our bodies. Our skeleton supports us so that we can stand up and hold our body up. Some bones protect special parts of our bodies, like the ribs that protect the heart and lungs and the skull that protects our brain. Some bones even help us to hear, like the tiny bones in our ears. They are the smallest bones in our bodies.

Joints are areas where two bones fit together. There are special kinds of joints, and some of them move. Our fingers, toes, elbows and knees are all hinge joints. Hinge joints allow bones to move back and forth in one direction. Our shoulders and hips are examples of ball and socket joints. In our shoulders, one bone has a rounded end that fits into the other bone. Ball and socket joints allow the bones to move around more freely than hinge joints. Our wrists and ankles are examples of gliding joints. In a gliding joint, one part of a bone slides over another bone. Mission 5 – page 5 Mission 5 – page 6

Bones are living, changing things that need the right nutrients and exercise to grow and stay strong. Bones are made up of living tissues, like blood vessels and nerves, and also of certain minerals like calcium. Calcium is a mineral that is found in dairy foods like milk, cheese, and yogurt. We need to eat foods with calcium because it helps our bones to stay strong.

Bones also work with our muscles to help us move. Our bodies have 650 muscles that work with bones to help our bodies move. Muscles also do other things that keep our bodies working. Muscles move our jaws so we can chew food or talk. Muscles help to move food through our bodies. Our heart is a muscle, and it pumps blood through our bodies. Muscles also help us to breathe and to stay warm.

A muscle can pull a bone to move it, but that same muscle cannot push the bone back to where it came from. So, muscles work in pairs to move bones back and forth. In your arm, the top muscle flexes to bring your arm bone closer to your body. The lower muscle in the pair is relaxed. Then, when you want to put your arm down, the lower muscle flexes and the top muscle relaxes. Mission 5 – page 7

Human Bodies in Space

On earth, gravity pulls down on us. It keeps the bones close together at their joints. But in space, there is no gravity pulling down on the bones and joints. The joints of astronauts spread out a little more in space, and fluid goes between the joints in the spine. This makes the astronauts about two or three inches taller in space than they are on Earth! They do not stay tall forever. Once astronauts come back to Earth, they shrink back to normal height because of the gravity.

Have you seen athletes who train with weights and barbells? Athletes lift weights so their muscles will get stronger by lifting up against something heavy. On Earth, our bones and muscles have to work against gravity to lift our arm over our head, to sit up straight after lying down, to bend our knees to start walking, and even to hold our heads up! In a way, working against gravity to lift our arm is exercise that helps to keep our muscles strong and in shape.

Space is a microgravity environment, which means there is almost no gravity for muscles and bones to work against. So, when an astronaut wants to move her arm, her arm bones and muscles are not working against gravity like they do on Earth. Because the astronaut does not have to work her muscles against gravity, her muscles can weaken in space. Astronauts have to do special exercises to keep their muscles strong while in space. If they didn’t, their arms and legs would feel like jelly when they landed back on Earth and they might not be able to stand! Mission 5 – page 8

Astronauts' bones become thinner and less dense the longer they stay in space. Astronauts on the International Space Station tend to lose about two percent of their body's total bone mass for each month they spend in space. That's because bone is living tissue. Bones are always being broken down by some cells and rebuilt by others. Without gravity and regular exercise, that balance is upset and more bone is lost than is gained. Eventually, a loss of bone density can lead to bone fractures and breaks, especially when they come back to Earth where gravity puts a strain on their weaker skeleton.

Astronaut Terence Hendricks exercising in space. Picture from NASA.

Changes in astronaut bones and muscles are very interesting to scientists and doctors. The study of bones and muscles in space may one day help us understand bone and muscle diseases on Earth to try to keep them from happening. By studying astronauts, scientists have learned more about one disease of the bones called osteoporosis (ah stee oh pour oh sis). In osteoporosis, bones become thin and break easily. Older people, especially older women, can get osteoporosis when they do not exercise enough or eat enough foods with calcium. You are less likely to get osteoporosis if you build up enough calcium in our bones at a young age, from childhood to teenage years, and keep exercising and eating right when you get older. Mission 5 – page 9

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 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 grow 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.

Another 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. What a great way to recycle. Mission 5 – page 10

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

Crop Talk

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

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 spacecraft with all of the materials needed to build it. So, plants that are large when they are fully grown may not be the best choice for the first crops in space.

2. Time - If your plant is grown with seeds, how long does it take for the seeds to germinate? Does the plant have an annual, perennial or biennial growing season?

Do you think it would be most beneficial to take a plant that had a seed-to-seed cycle of a few months or to take a plant that grew for two years before making seeds? Mission 5 – page 11

3. Harvest Index - This is a measure of how much of a crop is usable, or in our case, edible. Determine how much of your crop would be edible. For example, if sunflowers are one of the crops you chose, only the seeds are edible. But, for some crops, the entire plant is edible.

For example, of the two plants below, the lettuce crop has a higher harvest index than the sunflower crop. Why? Because you can only eat the seeds of a sunflower, and you can't eat the rest of the plant. Only a small part of a sunflower is edible. However, you can eat all of the lettuce plant. So the lettuce crop has the higher harvest index.

Which crop has the higher harvest index - apple or potato?

Remember, you have to look at the entire plant when determining the harvest index of the crop. Apples come from apple trees, which can be huge! Since the apples are only a small part of the whole tree, the harvest index for an apple crop is low. A potato grows on a potato plant, which is shown below. The potato plant is medium-sized, and it is much smaller than an apple tree. So the harvest index for a potato crop is higher than the harvest index for an apple crop.

Mission 5 – page 12

Remember that we learned about composting and the need to recycle plant waste in space because there is not much storage room for waste materials. Composting is a great option, but it would be even better if people could eat the majority of the plant and its parts.

4. Nutrition - Where does your plant fit on the food pyramid? What vitamins or minerals does your plant provide for people that makes it nutritious?

It is very important that the astronauts who go on a long trip into space have the foods they need to keep them healthy. That is why the nutritional value of the crops you select is very important.

Of course, there are other factors that can be important about the plants we select to take to the Moon. Does it taste good? Is the plant a pretty color? Does it make flowers and fruits that might help keep the crew's spirits up and give variety in their diets? Can the plant be used for other things, like making medicines or other products? There are obviously many things that scientists are considering when thinking about the best crops to take along on our first attempts to live somewhere other than Earth.

You have done a great job learning about the Moon, about plants and what they need to grow, and now about special considerations of growing plants in space. Now, let's put together the many things we have learned and design a model for Commander Spud Goodroot! We are almost official Agronauts! Mission 5 – page 13

Putting it Together Report

Look back at the information you have learned in Mission 5 and write a report to Commander Spud Goodroot answering the following questions:

1. What do you think is the greatest benefit of taking plants into space?

2. What are the pros and cons of each crop you selected to research?

3. After learning more about the three plants you selected, do you think they would be good choices for the first crops to grow on the Moon? Why or why not? Record your thoughts in your Agronaut Log.

Congratulations! You have completed Mission 5! Mission 5 – page 14

Mission 5 Glossary

adapt to make suitable to or fit for a specific use or situation astronaut a person trained to travel in space cephalad fluid shift when fluid that usually pools in the feet is moved towards the torso and head causing the face to puff up and the legs to get thinner. There is no gravity to pull fluid towards the legs so the fluid shifts to be distributed throughout the body. circumference the outer boundary of a circle or spherical object colonize to migrate to and settle in; occupy as a colony dwarf varieties smaller, miniature versions of plants that are just as nutritious as the larger ones edible fit to be eaten as food habitat area or environment where an organism normally lives harvest index proportion of usable (edible) crop materials over that which cannot be used or eaten horticulturalist a person whose job is cultivating and growing fruits, vegetables, flowers, or ornamental plants kilogram a measure of weight, equal to 1,000 grams or 0.454lbs weight a measure of the heaviness of an object