(CNN) -- The crew of the International Space Station marked the 10th anniversary of continuous human occupation of the orbiting science laboratory with a typical workday, pausing only briefly for a chat with NASA chief Charles Bolden and questions from international reporters.
"It's kind of mind-boggling when you stop and think about what you've done," Bolden told the crew. Bolden is a former NASA astronaut who flew on four space shuttle missions prior to the station's 2000 opening.
The football-field sized platform passed the 10-year mark early Tuesday, some 57,361 orbits of Earth after the first crew came aboard, according to NASA.
On October 25, the station eclipsed the previous record for constant human living in space, passing the Russian space station Mir.
Since the first module, the Russian-built Zarya, launched on November 20, 1998, 103 vehicles have traveled to the station, bringing 196 people to visit or live long-term and conduct science experiments and other work, according to NASA. The station has traveled more than 1.5 billion miles -- the equivalent of eight round trips to the Sun. Human habitation of the station began in 2000.
Bolden said the international flavor of the station's construction, supply system and staffing do more to prove that humans can get along than many earthbound diplomats, Bolden told the astronauts.
"You're part of an amazing legacy there on the station," he said.
People need look no further than the anniversary to recognize the station's most remarkable accomplishment, said astronaut Shannon Walker.
"Ten years of constant habitation in space is an amazing achievement in and of itself," she said.
But the station has also produced advances in science, medicine and environmental technology that are helping change life on Earth, according to NASA. The agency says more than 600 science experiments have been conducted aboard the station, with results helping produce new strategies to deliver cancer drugs, advances in vaccine development and a possible treatment for a form of muscular dystrophy, among other things.
The commemoration of the anniversary was clouded by the station's uncertain future. While the 15 nations involved in the space station program have agreed in principal to continue operating it for another decade, the United States is scheduled to retire its space shuttle fleet after two more flights -- cutting off a main supply route to get materials to the station.
While Russian spacecraft and commercial providers are expected to take up some of the slack and help keep the station operating for another 10 years, station crew members acknowledged that the shuttle's retirement will make the station's mission more challenging.
"I think it's not a real problem to supply the station with consumables and some other items, but I think it's a real problem to deliver the results," Russian cosmonaut Alexander Kaleri said during a news conference with reporters. "Now we can deliver only digital data, but sometimes it's necessary to bring back some physical items."