EAU CLAIRE (WQOW) - It's now been two decades since the first group of astronauts went to live and work long term on the International Space Station.
Since Expedition One got aboard the space station in November of 2000, it has been permanently crewed with up to nine astronauts from several different partnering countries, mainly the United States and Russia.
While the space race was part of what divided the two nations during the Cold War, the ISS has brought them together to further our understanding of space.
Dr. Paul Thomas, a professor of astronomy at UW-Eau Claire, said with the space station in operation for so long, it can be easy to take for granted what a tremendous achievement it is.
"There is a whole generation of people now, if you're a younger than 20 years old, you have never known a time when the human population wasn't seven odd billion on Earth and some in space and this all began with Expedition One," Thomas said.
Those aboard the International Space Station have been studying a wide variety of topics like meteorology, astronomy and the effects of zero gravity.