Astronaut Facts

Astronauts ['æs-trə-na:tz]

A person trained to work in a spacecraft.

Apollo 11 moon mission
Image courtesy of NASA

The name astronaut comes from the Greek words for “star-sailor.” Astronauts are most commonly associated with U.S. spacecraft. The word was formally adopted in 1958 by the National Aeronautics and Space Administration - otherwise known as NASA. Space travelers who fly for Russia are known as cosmonauts — from the Greek for “universe — sailor.” In China, space explorers are called taikonauts. This word is a blend of the Chinese word for “space” combined with the Greek word for “sailor.” Whatever we call them, they are great explorers and scientists.

Astronauts, cosmonauts, and many others have been important to the understanding we have of space. But in addition to learning about space, there have been a lot of other contributions to science and technology.


image courtesy of JPL

Before learning about the life of an astronaut it is important to know about the environment where astronauts work. Space is located approximately 76 miles above the Earth's surface, although the exact border between the Earth's atmosphere and the location of space is not well defined. Because it is above the atmosphere, there is no air - more specifically there is no oxygen.

image courtesy of JPL

We often hear people say that gravity does not exist in space. Gravity does exist and is the reason that the moon stays orbiting Earth or Earth continues to orbit the Sun. The gravity is weaker the further from an object you get. So because astronauts are miles above the Earth, there is less pull of gravity than if standing on the surface of the Earth. Scientists call it microgravity. Visit this NASA site to learn more about microgravity and how astronauts float in space. Visit the ScienceTrek site on gravity here.

Space is also not empty. There is a lot of distance between objects, but it is not empty. Stars, planets, moons, asteroids, comets, black holes, meteoroids, gaseous clouds, galaxies, and solar systems are among the objects found in space.

Space Isn't Like Home

Astronaut Shepard preparing for mission
image courtesy of NASA

Space is a dangerous place to travel, filled with unique challenges for working and living there. And yet, it somehow draws man to go there and explore this vast unknown. So what makes space so dangerous? Let's look at a few of the problems that scientists face in traveling and living in space.

The first big issue, which has already been discussed, is the fact that there is no oxygen in space. Astronauts just like all of us, need oxygen to breathe. So what do you do about getting oxygen? On Earth, we have plant life to recycle the gases around us and create oxygen for breathing.

tree leaves

The plants also remove carbon dioxide from the atmosphere in photosynthesis. In space, there are a few different methods for providing oxygen. The most obvious way is to carry tanks of oxygen with you. But how much is enough and what happens if it gets all used? Besides, pure oxygen is highly flammable, making it very dangerous to carry along. Interestingly enough, scientists use chemistry knowledge to create oxygen from the chemical reactions of the electrical generators on board the International Space Station — (ISS).

When humans breathe, they put off carbon dioxide as a waste product. Carbon dioxide gas is poisonous if there is too much of it. So there needs to be a way to get rid of the carbon dioxide that is exhaled in their breathing. Science has found ways to scrub the carbon from the breathable air. On Earth, we have plants that use carbon dioxide in their food-making processes to clean the air. Scientists have also found ways to use electricity to split water into oxygen and hydrogen — it is called electrolysis. At some point, scientists want to be able to use the leftover hydrogen and carbon dioxide to create water.

orbital debris around Earth
diagram of orbital debris around the Earth

Micrometeorites, orbital debris, and other particles are constantly flying past the astronauts' spacecraft, and the ISS, and when astronauts must perform a spacewalk, this material flies past their fragile space suits too. This matter can rip through delicate equipment or space suits causing damage or even death to an astronaut. Space is a dangerous place to go for a walk. Learn more about this danger here. Find out more about orbital debris here.

Extreme temperatures are another factor that makes space travel dangerous. On Earth, we have cool breezes and warming air from heat rising from the sidewalk to affect our temperatures. Because there is no air, temperatures are not impacted by air behavior. Consequently cold is really cold and hot is really hot. While the exact temperature is a complex question, it ranges from hundreds of degrees below freezing all the way to hundreds of degrees above freezing. Then there is the radiation - a kind of invisible wave of subatomic particles that can be dangerous to life and mechanical equipment. Much of this radiation comes from the sun.

In order to spend a lengthy time in space, astronauts have to carry all their food, and all their water, find a way to get rid of human waste, prevent boredom, keep a routine of cycles because there is no day and night, and live in cramped quarters. Sleeping, eating, and personal hygiene present problems in space.

astronaut exercising in space
image courtesy of NASA

Because of microgravity, the muscles of astronauts become weakened. Astronauts' bodies go through some difficult changes while they live and work in space. Special equipment is needed to provide exercise opportunities in space. Blood pressure, bones, muscles, and many organs and systems go through changes during their time in place. Astronauts actually get 1-2 inches taller while living in space. They return to normal height when they return to Earth and have time to adapt to gravity. Visit this site from NASA to learn about living in space.

Space Exploration

footprint on the moon
footprint on the moon image courtesy of NASA

Despite all of the danger, scientists continue to go to space and to explore more and more and travel further and further. Let's take a short look at the history of space exploration.

Launch of shuttle Discovery
Launch of Discovery image courtesy of NASA
  • Early 1930s to 1950s - early rocket launches and experiments
  • July 11, 1948 - a rhesus monkey made a test flight
  • October 4, 1957 - Russians launch Sputnik I into space
  • November 3, 1957 - Sputnik 2 which carried a dog, Laika, into space
  • January 31, 1958 - U.S. satellite Explorer I put into orbit
  • October 1, 1958 - NASA created - National Aeronautics and Space Administration
  • 1959 -1967 Multiple unmanned missions to the moon - U.S. and Russia
  • April 12, 1961 - Russian Yuri Gagarin - first person to orbit Earth
  • May 5, 1961 - Alan Shepard - first American to travel into space
  • February 20, 1962 - John Glenn - first U.S. astronaut to orbit Earth
  • During the 1960s the U.S. set a goal to land on the moon
  • June 14, 1964 - first woman in space - Cosmonaut Valentina Tereshkova
  • November 28,1965 - Mariner 4 launched to fly by Mars and take pictures
  • July 20, 1969 - Neil Armstrong was the first man to step on the moon
  • 1960s to the present - unmanned spacecraft photograph and study the moon, Mars, Jupiter, Saturn, Neptune, Uranus, the moons and rings.
  • May 14, 1973 - Skylab - a space station was set up
  • May 31, 1975 - The European Space Agency was created - 11 European nations began a program to explore space
  • July 15, 1975 - Apollo Soyuz mission - a joint U.S./Russian project
  • April 12, 1981 - Shuttle missions began which allowed reusable spacecraft
  • June 18, 1983 - Sally Ride became the first American woman in space
  • May 4, 1985 - Magellan unmanned spacecraft launched to explore Venus
  • April 24, 1990 - Hubble Space Telescope sent into space
  • March 19, 1991 - Japan launches its first moon mission
  • 1994-1998 - Joint mission between the U.S. and Russia - astronauts and cosmonauts live together on the Mir - this program prepared the way for the ISS
  • July 4,1997 - Sojourner Mars Rover lands to begin the surface exploration
  • November 2, 2000 - first crew of the ISS begins working together
  • February 12, 2001 - NASA lands a probe on Eros - an asteroid
  • September 27, 2003 - Europe's first moon mission - European Space Agency
  • January 3 and another on January 24,2004 - Mar's Rover missions land
  • July 1, 2004 - Cassini-Huygens probe orbits Saturn
  • July 21, 2011 - last shuttle mission comes to an end
Pathfinder image the Mars landscape
Pathfinder image the Mars landscape image courtesy of NASA

Many nations and private businesses have all jumped into space exploration over the years. The International Aerospace Information Network maintains a list of national space agencies.

This is just a small bit of the history of space exploration. Many steps took place between each of these events to make sure that space travel was safe and that problems found in previous steps were solved. Lots and lots of flights orbiting the Earth, trips to the moon, and trips to the ISS make up the manned space flights. There were some sad losses to human life in this history. Additional unmanned flights have gone to many of the planets in our solar system and beyond. Today, space exploration continues to be an important topic and discussion is underway to plan a manned mission to Mars.

At one time early in the history of space exploration, the U.S. and Russia seemed to be in competition with one another to be first, best, longer, and more. This was at one time called the “space race.” In more recent years Russia and the U.S. have been working in cooperation with one another, teaming up to create the International Space Station.

Training to Be An Astronaut

Mercury mission crew photo
Mercury mission crew photo courtesy of NASA

In the early days of the astronaut program, all U.S. astronauts were chosen from the military. They chose men with engineering training and flight experience. NASA thought these qualifications would be a good beginning. Seven men were selected as the original U.S. astronauts: L. Gordon Cooper, M. Scott Carpenter, John Glenn, Alan Shepard, Virgil I. Grissom, Walter Schirra, and Donald K. Slayton.

In time, military training became secondary to the capacity to learn and show academic ability. When an astronaut is selected, they must go through years of instruction to include earth science, meteorology, space science, other languages - including Russian, survival skills - including scuba training and swimming tests, medical training, jet flight, public speaking, weightless training, space station systems and much, much more. Above all, they must learn to work as a team with the others they serve. The final portion of their training is focused on their specific mission and the technology and science related to that mission.

STS-107 crew training
STS-107 crew training image courtesy of NASA

Most of the training is done at the Johnson Space Center in Houston, Texas, but time might also be spent in simulators and locations outside this location as necessary for the mission they will be assigned to do. Astronauts practiced walking on the “moon” in training for the Apollo Moon missions by going to Idaho's Craters of the Moon National Monument.

Astronaut Kelly in a training simulator
Astronaut Kelly in a training simulator image courtesy of NASA

Today there are two types of astronauts — pilot astronauts and mission specialist astronauts. The pilot astronauts are trained in piloting and flight and are concerned with the spacecraft and getting the rest of the crew and equipment to wherever that mission is headed — and back home safely. The mission specialists are the members of the crew that perform experiments, maintain equipment, and launch satellites. Mission specialists might be physicians, scientists, teachers, or engineers.


Astronaut on a spacewalk image courtesy of NASA

Sometimes astronauts are required to leave the safety of the spacecraft or the ISS and go out into space. They might need to repair something on their craft or they might be performing an experiment. For a spacewalk, they put on a special protective suit that maintains their body temperature, protects them from radiation, and provides an artificial environment for breathing. They are also tethered to their craft by a line so that they don't drift away. Learn more about spacewalks from NASA's website here.


A number of inventions that came out of the space program are helping us non-astronauts every day. You might find some of these to be surprising. Here are just some of the innovations that came through the space program that you, your family, or your friends may be using right now: scratch resistant lenses in glasses, satellite communications, improved cordless power tools, water filter systems, memory foam, CAT scanners - used in hospitals to diagnose, invisible braces, freeze dried food, cochlear implants — used to give hearing to the deaf, life shears — a kind of cutting tool used by emergency workers and firemen, ear thermometers, improved fire detectors, and pacemakers. These are just a few you might have come in contact with, but since 1976 there have been approximately 1400 inventions from the space program that have been used in industry, medicine, and the home. Here is a timeline from 2008 that shows how the various inventions from NASA have benefitted society.

solar powered satellite
solar powered satellite image courtesy of NASA

International Space Station

International Space Station
International Space Station image courtesy of ISS

The International Space Station (ISS) is an orbiting science laboratory and also a docking port for international space flights. It orbits the Earth about 240 miles from the surface. Astronauts and cosmonauts work together on the station and crews change about every six months with a rotating schedule that has been keeping the station functioning since November 2000. The station is constantly under construction and is currently the size of approximately two commercial airplanes. It is the largest piece of equipment to ever orbit the Earth.

The ISS is powered using solar panels to convert the sun's energy to usable electricity. Supply ships from Earth come on a regular basis to provide needed food, water, and other supplies necessary for life and for the ongoing experiments, repairs, and construction on the station. To see the current view of Earth from the ISS - click here.

Idaho's Astronaut

Astronaut Barbara Morgan
Astronaut Barbara Morgan photo courtesy of NASA

Barbara Morgan was chosen in 1985 as part of the “Teacher in Space Program” to train to be an astronaut. She was at that time, teaching at McCall-Donnelly Elementary in Idaho. In 1998 she was chosen by NASA to become a mission specialist. She became the first Teacher in Space on August 8, 2007; flying on board the Endeavor Space Shuttle. To learn more about Barbara Morgan, click here.

Lots of Help

It takes more than just the people aboard a spacecraft to run a mission. There are about 270 experts, the ground controllers, who work on the ground at the Johnson Space Flight Center. This earth crew is divided into different groups to make sure each part of a mission is well planned and carried out. The Flight Dynamics Department is responsible for orbital maneuvers. Payloads are in charge of the shuttle cargo. There is a department for Guidance, Navigation, and Control Systems. The communications group directly talks to the shuttle's commander. A flight director is the top authority for each shuttle mission.

1969 mission control room
1969 mission control room image courtesy of NASA

You don't have to be an astronaut or a part of the Earth crew to be a part of space exploration. Those who design and build the shuttles, space stations, rockets, computers, and navigation systems are a part of the exploration team. You can be a mechanical engineer, machinist, electronic assembler, manager, or part of the administrative support team. Aerospace Scientists can be astronomers, chemists, physicists, biologists, geologists, and botanists. If you think space is the place for you, click here to learn more about careers in space exploration. You'd be surprised how many people it takes to get a mission off the ground and to its completion.

STS-86 Atlantis shuttle on crawler
STS-86 Atlantis shuttle on crawler image of NASA

Top 10 Questions

Thanks to Amy Ross, Space Suit Designer, NASA; and Duane Ross, Manager for Astronaut Candidate Selection and Training, NASA for the answers.

  1. Is it cool to work in space?

    I can't think of anything cooler than working in space. If you are on the international space station going around the Earth, all you have to do is let go and you just kind of float around and use your fingertips to push from one side to the other. You could look out one window and see Earth, and look in another direction and see the stars. (From Daniel at Collister Elementary School in Boise)

  2. How old do you have to be to go into space?

    It varies. Right now, when you go into space, you have to have a degree in engineering, science or math. So, the key for anyone who wants to go into space is to stay in school, do well, and to be involved in a lot of activities. We look for well-rounded people to send into space and the ages have ranged from 26 to 46. We have even sent people into space that are 70 years old. (From Hannah in Illinois)

  3. How do you eat in space?

    You eat in space a lot like you eat on the ground. You just have to be very careful how you get food from your plate to your mouth. If you scoop it too fast, it'll fly off your spoon and may hit you in the face. Foods that crumble are usually avoided as pieces may fly about. So, peanut butter is spread on tortillas instead of bread. (From Melanie at White Pine Elementary School in Boise)

  4. How long do astronauts have to train before going into space?

    Astronauts have to do a lot of training before going into space. Initially, there is a basic program that is two years. There they learn how to fly, learn about the systems aboard a spacecraft, to speak Russian, to do spacewalks, to operate robotic manipulator arms, etc. Then, once you are assigned to an international space station mission, there is an additional training for that mission that takes two and a half years or more. So basically, it can take around five years from the time you walk in the door. (From Chloe at Owyhee Harbor Elementary School in Boise)

  5. How many female astronauts are there?

    The first group of women to be selected for the space program was a group of six for the astronaut class of 1978. Since then, we've selected about 52 women to participate in the space program. They are from all different backgrounds and some have trained as pilots, some are scientists, and some are engineers. (From Katherine at Dalton Gardens Elementary School in Dalton)

  6. Why do astronauts get weaker in space?

    We use a lot of muscle just to stand up and move around. The Earth is a massive planet that creates gravity. The gravity makes you work when you stand up and move about. When you go into space, there is only a little bit of gravity, microgravity. Your muscles don't have to work very much, and if you don't work your muscles, they get weaker. We use resistant exercise equipment on the space station to help the astronauts' muscles stay strong. (From Bregan at Owyhee Harbor Elementary School in Boise)

  7. Why do astronauts wear suits?

    The space suits keep the astronauts alive. Space is a vacuum, meaning there is no air. The suits provide the astronauts with air and pressure so they can stay alive. Space can also be very hot or very cold. The suits help to provide protection from the extreme temperature variations. There are also tiny bits of debris flying around in space at very high rates of speed, 17,500 miles per hour! An astronaut wouldn't want a hole in their suit, which could happen when they are hit by the debris. So, the suits protect them from that too. Another reason for the suits is that they allow the astronaut to be able to move around and get the work done that is needed. (From Adriana at Cynthia Mann Elementary School in Boise)

  8. How often can you go into space?

    You can go into space fairly routinely. We've had astronauts who have flown into space as many as seven times. There isn't a limit, and if you have a reason to do so, you could go quite a few times. It also depends on how long an astronaut stays in space. Are they on a two-week shuttle mission, or have they gone to the international space station where they could stay for a year? You can't do as many long duration missions. Astronauts also have to worry about other things, like radiation from the sun. There are many factors that determine how many times people can go into space. (From Katie at Dalton Gardens Elementary School in Dalton)

  9. Why is there gravity on Earth but not in space?

    Actually, there is gravity everywhere. On Earth, the mass of the earth pulls us toward Earth. It's the mass of the Earth that allows us to have the gravity we have. When you are in space, or on a space station, you would be falling around all the time. It's like if you were in an elevator that is falling - it would feel like you were weightless. (From Henry at Roosevelt Elementary School in Boise)

  10. Why do people go to the moon?

    Some people go to the moon because they like to explore. They want to see what's there. On a more practical side, we learn a lot when we go to the moon. We learn about the origin of the moon, where it came from, how it formed, and what it's made out of. (From Madison at Cynthia Mann Elementary School in Boise)