And the world was treated to the first recital of traditional Japanese music and poetry in space.
Monday marked the 49th anniversary of the first human spaceflight - by Soviet cosmonaut Yuri Gagarin on April 12, 1961 - and the 29th anniversary of the first shuttle launch.
In honor of Russia's Cosmonauts Day, Russian President Dmitry Medvedev called the residents of the International Space Station to wish them well. Three are Russian, two are American and one is Japanese.
"Space is something that unites all of us. It's a global issue," Medvedev told them.
He added: "Space is our highest priority, regardless of how hard the economic situation was in the country and will be, I'm sure."
Later in the morning, the two Japanese on board - the space station's Soichi Noguchi and visiting shuttle astronaut Naoko Yamazaki - took a call from Japanese dignitaries and schoolchildren in Tokyo.
This is the first time two Japanese astronauts have flown together in space. Yamazaki shared a haiku - or Japanese poem - she wrote after seeing Earth for the first time from space. Then, with Noguchi accompanying her on an electric keyboard, she performed a Japanese folk music springtime piece, "Sakura Sakura," which translates as "Cherry Blossom." Noguchi opened the piece with a few notes on a traditional wooden flute.
"This is probably the first time that you are going to hear the historic performance from space," Noguchi said.
The recital took place in Japan's big science lab, Kibo, or Hope. Yamazaki will depart the space station Saturday, along with her six U.S. shuttle colleagues.
One more spacewalk still needs to be conducted to finish installing a new ammonia tank, on Tuesday. The astronauts will place a big cargo carrier back aboard Discovery on Thursday, after it's stuffed with old equipment and trash. Then on Friday, the shuttle will be inspected for any signs of micrometeorite damage.
This survey of the shuttle wings and nose usually is conducted after undocking. But Discovery's main antenna is broken, and there would be no way to transmit all the laser 3-D images to Mission Control for analysis. NASA added a day to the shuttle's visit so the inspection could be carried out at the station and the data could be sent using station resources.
Shuttle inspections became mandatory in space following the 2003 Columbia disaster.
Columbia lifted off on the first shuttle flight on April 12, 1981.