SCIENTIFIC EXPERIMENTS

During their stay on the ISS, astro­nauts carry out various experiments designed to study Earth from space. They also test and extend scientific and medical knowledge about the effects of spaceflight travel on the human body, animals, and plants.

The ISS is a science laboratory in orbit, with ongoing experiments in astronomy, physics, crystal growing, metallurgy, biology, and space engineering. Scientists in the space station can do research under the microgravity conditions that do not exist on Earth.

A new way to produce oxygen in space could be from plants, which release oxygen naturally during their food-making process, photosynthe­sis. One objective of sending astro­nauts to the ISS is to develop "space­gardening." A journey to and from Mars would take eighteen months – if astronauts are to build bases on Mars and stay there for months, they will need to make their own air. They could grow plants, both for food and to generate oxygen. The ISS has greenhouses in both the Destiny lab­oratory and in the Zvezda service module for plant experiments. The astronauts keep a record of the plants’ growth and harvest samples of their crops to send back to Earth.

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given off in small quantities by the human body, to prevent these gases from building up to unpleasant or dan­gerous levels.

Most of the oxygen inhaled by ISS astronauts is made by electrolysis, using electricity from the station’s solar pan­els. In the process of electrolysis, water is split into hydrogen gas and oxygen gas. Water is made of these two gases: each molecule of water contains two hydrogen atoms and one oxygen atom. Passing an electrical current through water causes these atoms to separate and to recombine as hydrogen and oxygen.