International Space Station facts for kids

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International Space Station
A rearward view of the International Space Station backdropped by the limb of the Earth. In view are the station's four large, gold-coloured solar array wings, two on either side of the station, mounted to a central truss structure. Further along the truss are six large, white radiators, three next to each pair of arrays. In between the solar arrays and radiators is a cluster of pressurised modules arranged in an elongated T shape, also attached to the truss. A set of blue solar arrays are mounted to the module at the aft end of the cluster.
The International Space Station on 23 May 2010 as seen from the departing Space Shuttle Atlantis during STS-132.
Station statistics
SATCAT № 25544
Call sign Alpha, Station
Crew Fully crewed: 6
Currently aboard: 6
(Expedition 54)
Launch 20 November 1998 (1998-11-20)
Launch pad
  • Baikonur 1/5 and 81/23
  • Kennedy LC-39
Mass ≈ 419,455 kg (924,740 lb)
Length 72.8 m (239 ft)
Width 108.5 m (356 ft)
Height ≈ 20 m (66 ft)
nadir–zenith, arrays forward–aft
(27 November 2009)
Pressurised volume 931.57 m3 (32,898 cu ft)
(28 May 2016)
Atmospheric pressure 101.3 kPa (29.9 inHg; 1.0 atm)
Perigee 401.1 km (249.2 mi) AMSL
Apogee 408.0 km (253.5 mi) AMSL
Orbital inclination 51.64 degrees
Orbital speed 7.67 km/s
(27,600 km/h; 17,200 mph)
Orbital period 92.65 minutes
Orbits per day 15.54
Orbit epoch 7 July 2017, 13:10:09 UTC
No. of orbits 102,491 as of July 2017
Orbital decay 2 km/month
Statistics as of 9 March 2011
(unless noted otherwise)
The components of the ISS in an exploded diagram, with modules on-orbit highlighted in orange, and those still awaiting launch in blue or pink
Station elements as of June 2017
(exploded view)

The International Space Station (ISS) is a space station, or a habitable artificial satellite, in low Earth orbit. Its first component launched into orbit in 1998, the last pressurised module was fitted in 2011, and the station is expected to be used until 2028. Development and assembly of the station continues, with components scheduled for launch in 2018 and 2019. The ISS is the largest human-made body in low Earth orbit and can often be seen with the naked eye from Earth. The ISS consists of pressurised modules, external trusses, solar arrays, and other components. ISS components have been launched by Russian Proton and Soyuz rockets, and American Space Shuttles.

The ISS serves as a microgravity and space environment research laboratory in which crew members conduct experiments in biology, human biology, physics, astronomy, meteorology, and other fields. The station is suited for the testing of spacecraft systems and equipment required for missions to the Moon and Mars. The ISS maintains an orbit with an altitude of between 330 and 435 km (205 and 270 mi) by means of reboost manoeuvres using the engines of the Zvezda module or visiting spacecraft. It completes 15.54 orbits per day.

Building the ISS began in 1998, when a Russian and American space modules were connected with each other.


Unity-Zarya-Zvezda STS-106
ISS configuration in 2000: from top to bottom, the Unity, Zarya, and Zvezda modules

In the early 1980s, NASA planned Space Station Freedom as a counterpart to the Soviet Salyut and Mir space stations. It never left the drawing board and, with the end of the Soviet Union and the Cold War, it was cancelled. The end of the Space race prompted the U.S. administration officials to start negotiations with international partners Europe, Russia, Japan and Canada in the early 1990s in order to build a truly international space station. This project was first announced in 1993 and was called Space Station Alpha. It was planned to combine the proposed space stations of all participating space agencies: NASA's Space Station Freedom, Russia's Mir-2 (the successor to the Mir Space Station, the core of which is now Zvezda) and ESA's Columbus that was planned to be a stand-alone spacelab.

The first section, the Zarya Functional Cargo Block, was put in orbit in November 1998 on a Russian Proton rocket. Two further pieces (the Unity Module and Zvezda service module) were added before the first crew, Expedition 1, was sent. Expedition 1 docked to the ISS on November 2, 2000, and consisted of U.S. astronaut William Shepherd and two Russian cosmonauts, Yuri Gidzenko and Sergei Krikalev.


Module Launch vehicle Launch Date Separate View View with station
Zarya Proton-K 1998-11-20 Zarya.jpg Zarya.jpg
Unity Space Shuttle Endeavour 1998-12-04 ISS Unity module.jpg Sts088-703-019e.jpg
Zvezda Proton-K 2000-07-12 ISS Zvezda module-small.jpg Unity-Zarya-Zvezda STS-106.jpg
Destiny Space Shuttle Atlantis 2001-02-07 ISS Destiny Lab.jpg Sts098-312-0020.jpg
Quest Space Shuttle Atlantis 2001-07-12 ISS Quest airlock.jpg ISS on 20 August 2001.jpg
Pirs Progress M-SO1 2001-09-14 Pirs docking module taken by STS-108.jpg S108e5628.jpg
Harmony Space Shuttle Discovery 2007-10-23 Harmony Relocation.jpg ISS seen from STS-122.jpg
Columbus Space Shuttle Atlantis 2008-02-07 Columbus module in orbit.jpg
Kibo(ELM) Space Shuttle Endeavour 2008-03-11
Kibo(PM) Space Shuttle Discovery 2008-05-31
S6 Truss and Solar Arrays Space Shuttle Discovery 2009-03-15
Poisk Progress M-MIM2 2009-11-10
Tranquility and Cupola Space Shuttle Endeavour 2010-02-08 Tranquility-node3.JPG
Rassvet Space Shuttle Atlantis 2010-05-14
Leonardo Space Shuttle Discovery 2011-02-24 Leonardo PMM module.jpg

Life in space

Bedtime The scientists living in the space station have to get used to all kinds of changes from life on Earth. It takes them only 90 minutes to orbit (go around) the earth, so the sun looks as if it is rising and setting every 45 minutes. This can be pretty confusing, especially when you are trying to decide when you should go to bed! The astronauts try to keep a 24-hour-schedule anyway.

When it really is bedtime, they have to sleep in sleeping bags that are stuck to the wall. They have to strap themselves inside so they will not float away in the middle of a nice dream.

Zero gravity
In space there is no gravity (this is called zero gravity). To help prepare astronauts experience zero gravity, NASA trainers put the astronauts in the water. Because water makes you float, this is a little like experiencing no gravity. However, in water you can push against the water and move around. In zero gravity, there is nothing to push against, so you just float in the air. Another way of training is going in a plane and making the plane fall to earth very quickly. This lets people experience zero gravity for a very short time. This training can make people quite sick at first.
Since in zero gravity, the astronauts do not use their legs very much, they need to get lots of exercise to keep them from becoming too weak (without gravity, astronauts can get big upper bodies and skinny legs. This is called chicken-leg syndrome). Lots of exercise is needed to keep the astronauts healthy every day.

Eating in space style is pretty hard, too. Water and other liquids do not flow down in space, so if you spilled some milk in a space station, the milk would float around everywhere! Liquids ruin electric equipment, so astronauts have to be very careful in space. They drink by sucking water out of a bag, or from a tube stuck to the wall. They can not put their food on plates because it would just float right off, so they put it in pouches and eat from the pouches. The food is usually dried, because crumbs are very messy things that can ruin the equipment.
Sometimes fresh fruits and vegetables are sent up to the astronauts, but it is very expensive and hard to send it, so they have to prepare a lot of food before they go.

Using the bathroom in space
Actually, in space, the bathroom should probably be called the restroom instead, because you really can not take baths there. Instead, astronauts use squirt guns to take a shower! One person squirts himself with a gun while other people stand outside with a water vacuum to get rid of all the water that floats out of the shower. This is quite hard, so astronauts usually just take a "sponge bath" with a wet cloth.
Toilets can be another problem. Toilets are supposed to use gravity to work. When you flush the toilet, gravity makes the water go down. Since the astronauts on the ISS do not feel any gravity, the toilet must be attached to the astronauts and gently suck away all their waste.

Images for kids

International Space Station Facts for Kids. Kiddle Encyclopedia.