U.S. President Barack Obama thanked the astronauts onboard the International Space Station Tuesday, saying he was extraordinarily proud of them.
A group of school children and members of Congress joined the president for a video conference call from the White House Tuesday with the space station's crew.
During the call, students asked the astronauts a range of questions, including whether they have discovered any life forms 355 kilometers above the Earth's surface and whether they play video games aboard the station.
The astronauts said there are no life forms yet but that they are continuing experiments; and they said they do have video games aboard, but there is not much time to play.
ISS Commander Mike Fincke ended the conference by saying the space station is an example of what humans can do when they come together "constructively, instead of destructively."
The U.S. space agency, NASA, says 15 countries are involved, both on the ground and in space, with the construction and operation of the space station.
Astronauts aboard the International Space Station performed three spacewalks on the current mission of the U.S. space shuttle Discovery.
The shuttle is scheduled to return to Earth on Saturday.
Some information for this report was provided by AP.