Although very expensive, space exploration is very important for our development as a society and may be very important for the continued survival of the human race someday. It is great that there is a place for astronauts of different countries to come together to learn more about the stars. I think that the teamwork will help us gain knowledge at a faster rate.
The International Space Station has been worth the billions of dollars invested in it because it has given us information on how long-term space living affects the human body. This information is invaluable for when the human race will travel long distances in space. It also has allowed us to find out how plants can be grown in space and how many, many things react to prolonged exposure to space.