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Astronauts: Facts

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 that 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.

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 obit 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.

Image courtesy of JPL

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

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. 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 the 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 the 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 left over hydrogen and the carbon dioxide to create water.

Space Walk

Micrometeorites, orbital debris and other particles are constantly flying past the astronauts' spacecraft, 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 lengthy time in space, astronauts have to carry all their food, 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.

Image courtesy of NASA

Because of microgravity, 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

Space Shuttle launch
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.

  • 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.
  • Moon Footprint
    Image courtesy of NASA
  • 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
Mars Scape
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 7
Image 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.

Image courtesy of NASA

In time, the 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.


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.

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.


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 which 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.


Image courtesy of NASA

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.

International Space Station

International Space Station
Image courtesy of NASA

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

Barbra Morgan
Image 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

NASA Space Command
Image courtesy of NASA

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 is 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.

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.

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