20 years ago today, just two days after leaving Earth, an astronaut and two cosmonauts arrived at the International Space Station. The station has been occupied every day since then.

The crew of Expedition 1 consisted of American Bill Shepherd, the mission commander, and two Russians — Yuri Gidzenko and Sergei Krikalev.

When they arrived, the station was a barebones operation — only three modules and some solar panels had been put together. During Expedition 1’s four and a half months in orbit, though, another module and some giant solar panels were added to the complex.

Since then, the station has been expanded even more. It’s by far the largest object ever placed in space. It circles Earth 16 times a day, at an average altitude of about 250 miles. It hosts many research projects, including several that look out into the universe.

About 240 people from 20 countries have visited the station, with up to six living and working there for months at a time.

The station has been approved to continue through 2024. And NASA and other space agencies are talking about keeping it in orbit even longer — extending an occupation that began 20 years ago.

Script by Damond Benningfield

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