Gently bouncing up and down in microgravity aboard the International Space Station, NASA's Jeffrey Williams delivered a message to the people of Earth.

"Monday, May 16, 2016, at 06:10 at GMT, the ISS will begin its 100,000th orbit as it crosses the equator," Williams said in a video, calling the feat a "significant milestone."

Nearly 18 years after its initial launch, the ISS has traveled 100,000 laps — 2.6 billion miles — around planet Earth, according to a statement from NASA.

Traveling at speeds of nearly 18,000 miles per hour, the craft takes about 90 minutes to complete one orbit. This means the astronauts living on-board experience 16 sunrises and sunsets in a 24-hour period.

Right now, there are six astronauts on the ISS: Williams, from the U.S.; Tim Kopra, also from the U.S.; Russian cosmonauts Yuri Malenchenko, Oleg Skripochka, and Alexey Ovchinin; and British astronaut Tim Peake.

Williams said in the video that the 100,000-orbit mark was a "tribute to international partnership made up of the European Space Agency, Russia, Canada, Japan and the United States."

He said more than 220 astronauts and cosmonauts from 18 different countries have been on the ISS since its "first element launch" in 1998.

Since humans began living and working on the ISS continuously in 2000, they've repeatedly pushed the boundaries of what's possible for life in space. In March, astronaut Scott Kelly returned from nearly one year in space, the longest-lasting space flight ever.

And last month, the current ISS commander, Peake, ran the London marathon from space, as the Two-Way reported. Harnessed to a treadmill to keep from floating away, Peake finished the race with an estimated time of 3:35.21.

As Williams said in his video message, this is just the beginning.

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