Researchers from governments, industry and educational institutions can use the facilities on the ISS. But why would they want to? The ISS is used mostly for scientific research in the unique environment of microgravity. Gravity influences many physical processes on Earth. For example, gravity alters the way that atoms come together to form crystals. In microgravity, near-perfect crystals can be formed. Such crystals can yield better semi-conductors for faster computers or for more efficient drugs to combat diseases.
Another effect of gravity is that it causes convection currents to form in flames, which leads to unsteady flames. This makes the study of combustion very difficult. However, in microgravity, simple, steady, slow-moving flames result. These types of flames make it easier to study the combustion process. The resulting information could yield a better understanding of the combustion process, and lead to better designs of furnaces or the reduction of air pollution by making combustion more efficient.
Long-term exposure to weightlessness causes our bodies to lose calcium from bones, tissue from muscles, and fluids from our body. These effects of weightlessness are similar to the effects of aging (decreased muscle strength, osteoporosis). So, exposure to microgravity may give us new insights into the aging process. If we can develop countermeasures to prevent the degrading effects of microgravity, perhaps we can prevent some of the physical effects of aging. The ISS provides long-term exposure to microgravity that could not be obtained by using other spacecraft.
The ISS allows us to test ecological life support systems that are similar to the way that the Earth provides life support. We can grow plants in large quantities in space to make oxygen, remove carbon dioxide and provide food. This information will be important for long interplanetary space voyages, such as a trip to Mars or Jupiter.
Orbiting above the Earth's atmosphere and equipped with special instruments and telescopes, the ISS crew can observe and take various measurements of the Earth's surface (amount of vegetation, temperature, water) and the Earth's atmosphere (carbon dioxide content, lightning strikes, hurricane development). Crew members can also use telescopes to observe the Sun, stars, and galaxies without distortion from the Earth's atmosphere.
For details on specific projects and experiments, you can check out the ISS Facility and Experimentation Web site. Now let's take a look at the future of the ISS.