At $410 million, Pirates of the Caribbean: On Stranger Tides holds the record for the most expensive movie ever made. But that lofty price tag is pocket change. Especially when compared to the over $100 billion spent on constructing the International Space Station (ISS). This makes the ISS the most expensive object ever built by humans.

How the International Space Station was conceived

First proposed in the early 1980s, the ISS was originally conceived as a joint project between the United States and Soviet space programs. Following the dissolution of the Soviet Union in 1991, Russia took over their role. Additional partners including Japan, Europe and Canada eventually came onboard. The European Space Agency alone represented the interests of 15 countries.

With five major space agencies collaborating, you can imagine the political and logistical challenges. “There was never really a strong push to abandon it but there were threats,” says Valerie Neal, a space historian at the Smithsonian National Air and Space Museum. “It was very nearly killed by a single vote at one of the committees of the U.S. Congress.”

Putting the pieces together

Despite the bumpy road to get the project approved and funded, the first module of the International Space Station was finally launched in 1998. More pieces were gradually added as assembly continued over the next decade. The station was ready for continuous occupation by 2000. Since then, it has been manned nonstop by a rotating international crew of between 3 and 6 astronauts and cosmonauts.

The orbiting space laboratory and the research

Orbiting roughly 250 miles above the Earth’s surface, the football-field-sized ISS serves as a high-tech microgravity laboratory. Experiments conducted on board have led to advances in medicine, technology, and our understanding of how the human body adapts to weightlessness.

For example, research on the ISS helped identify a salmonella vaccine. It also helped develop a new water purification system that can benefit remote regions here on Earth. Astronauts have also gained insight into how to prevent bone and muscle loss in space. This knowledge can be applied to tackling osteoporosis and aging back home.

“The space station builds understanding of how to operate far away from Earth—lessons needed for the Moon and Mars,” says Neal. She believes the costs, though massive, have been justified by the knowledge gained.

Future plans for the International Space Station

While NASA has Historic plans to retire the ISS by 2030, many argue it is a mistake to abandon this epic engineering achievement after investing so much in its construction and operation. The ISS has fostered unprecedented global cooperation in space exploration.

Its continuous human presence over the past two decades has also provided consistency for conducting research. Scientists contend that decommissioning the ISS would drastically reduce access to space-based microgravity research right when they are making major breakthroughs.

Regardless of its future, as the most expensive structure ever constructed, the International Space Station stands as an enduring symbol of what humans can accomplish through determination, teamwork and scientific imagination. The price tag is astronomical, but so too are the rewards.

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