The International Space Station


The International Space Station is a large satellite that orbits the Earth at an altitude of between 300 and 460 km. It travels at a speed of 27,000 km an hour (17 000 mph). The space station serves as a laboratory for scientific experiments in many fields. The spacecraft is also used to make tests for future missions that will travel to Mars and other planets.

The International Space Station is not owned by a single country. It is a project carried out by the space agencies of many nations. Japan, Russia , the USA and European countries have sent astronauts and scientists to the space station in the last decade.

The first part of the ISS was launched into orbit by the Russian Soyuz spacecraft in 1998. Since then Russian and American spacecraft have been delivering modules to expand the space station. During this period of time crews have been constantly arriving and leaving the ISS. The space station, with its over 30 modules, is scheduled to be finished in 2012 and will stay in orbit until at least 2020

Before sunrise or after sunset you can see the ISS with the naked eye as a slow bight moving dot across the sky. The ISS is the biggest man-made object orbiting the earth, about as bright as Venus.


Experiments and research

Because of zero gravity scientists on the ISS can carry out experiments that cannot be done on Earth. They check out the effects that zero gravity has on plants and animals, or they can mix together fluids which react differently in space.

Scientists on Earth can watch the experiments or carry out new ones. They can also monitor the crew’s data. Even students around the world can take part in certain ISS experiments and compare results.

Living on the ISS for a longer period gives researchers an insight on how the human body changes when it is exposed to weightlessness for a longer time. This data is important in order to see how astronauts react when they go on a longer trip, for example ,to Mars. Such an expedition would take almost three years to complete.

Living on board the ISS

The atmosphere that is created on board the ISS is like the earth’s atmosphere.
The food that the astronauts eat is mostly frozen and canned. There are kitchen appliances, like warmers and refrigerators on board. Drinks are made by adding water to powder. Waste is collected in bags and then carried away by an air stream.

The space station gets its power from solar sails that turn the sun’s energy into electricity. They are much more efficient that than the solar cells on Earth. Some of the energy is turned into heat which keeps the space station at the same temperature all the time.

Oxygen is delivered to the ISS by spacecraft from earth. It can also make breathable air from recycled water .





A typical day for the ISS crew begins at six o’clock. After breakfast they have a conference with ground controllers before work starts. A lunch break and more work and exercises lead them up to 19.30. Then they have dinner, another conference and go to sleep at about ten.


Health risks and effects of long-term space travel

Although low earth orbit partly protects the ISS astronauts from radiation, they still are exposed to radiation levels that are five times higher than those in a passenger airplane.

There are a number of health risks in long-term space travel. Muscles and bones become weaker. Pumping blood into the heart slows down and the immune system weakens. To prevent this from happening, astronauts and scientists have to exercise regularly. For this purpose there is equipment for weightlifting, a stationary bicycle and a treadmill on board.

Microgravity is similar to what we experience when we get older. So scientists can get new insights on the aging process.


Related Topics




  • air stream = flow of air that leads into space
  • although = while
  • altitude = height
  • appliance = machine
  • break = pause
  • breathable = to be able to pass through into your lungs
  • canned = in a round metallic container
  • carry out = do
  • compare = check, contrast
  • complete = finish
  • constantly = always; without a break
  • create = make
  • crew = the people who work on board the spaceship
  • data = information
  • deliver = to bring to
  • dot = small spot, mark
  • effect = result, outcome
  • efficient = they produce more energy
  • electricity = the power we use to make light or heat up a room
  • equipment = machines for a certain job
  • exercise = to do sports or other activities to stay healthy; to move your arms and legs
  • expand = to make larger
  • expedition = trip
  • experience = to go through
  • expose = here: to be put under the influence or control of
  • fluid = liquid, like water
  • frozen = to be preserved a very low temperature
  • future = coming
  • ground controller = person who watches the space station from the Earth
  • insight = an understanding of something
  • long-term = for a long time
  • microgravity = no gravity at all; to feel completely without weight
  • mission = expedition, trip
  • monitor = watch
  • mph =miles per hour
  • naked eye = without a telescope
  • orbit = to go around
  • own = belong to
  • oxygen = a gas that is in the air, which we breathe and need to live
  • partly = somewhat
  • period = time
  • power = energy
  • prevent = stop
  • process = actions that are done to get a certain result
  • protect = guard, defend
  • purpose = reason
  • radiation = energy in the form of light or heat waves that you cannot see
  • recycle = to use over and over again
  • refrigerator = a machine that keeps food cool
  • researcher = scientist; a person who tries to discover new things about a certain field
  • sail = a large piece of material fixed to a long pole
  • satellite = a machine that goes around the Earth, moon or another planet; it is used to send data back to Earth
  • schedule = plan
  • serve = work as
  • similar = like
  • slow down = to become slower
  • space = the area outside the Earth; the planets , sun and stars
  • spacecraft = spaceship
  • speed = how fast something is
  • stationary = fixed to the floor
  • treadmill = a machine with which you can run on a moving belt and stay at the same place all the time
  • waste = materials that are left over, which you don’t need any more
  • weaken = to become weaker
  • weightlessness = something that seems to have no weight; it floats
  • weightlifting = to lift pieces of metal into the air
  • zero gravity = when there is no force that pulls you down