KOROLYOV, Russia -- U.S. and Russian officials gathered Monday at mission control here to mourn the crew of the shuttle Columbia and pledge continued international cooperation in space exploration.
Russian space officials said they would shelve plans to carry more tourists to the international space station and would use their spacecraft only to deliver long-term crews. They also offered to build spacecraft to help make up for the loss of shuttle flights during the investigation.
During the memorial ceremony in Korolyov, just outside Moscow, U.S. astronauts and Russian cosmonauts observed a moment of silence for the seven Columbia astronauts, whose pictures were displayed on the big screen in the control room.
"We are deeply mourning," said Russian cosmonaut Valery Tokarev, who flew aboard the shuttle Discovery in 1999 with Rick Husband, Columbia's commander. "Rick Husband was a great friend and an excellent pilot."
The U.S. Ambassador to Moscow, Alexander Vershbow, told mourners that the two countries - space-race foes during the Cold War - should continue their cooperation on the international space station.
"The space community that gathered here today will carry out the pledge of our presidents ... to work together as we deal with the aftermath of the accident, ensuring that the joint work on the international space station continues," Vershbow said. "It's challenging work, it's dangerous work, it's honorable work."
Russian space officials said they could keep the station manned by using Russian spacecraft instead of shuttles - provided the United States and other participants in the 18-nation project help pay the additional cost.
Russia must send two Soyuz capsules and three Progress supply ships to the station each year under an agreement with other partners in the project. Without shuttle missions, four or five Progress ships would be needed, said Yuri Semyonov, head of the state-run RKK Energia company, which builds the spacecraft that fly to the orbiting complex.
"We will need money for that," Semyonov said. "If we get the money, we will mobilize all our resources and provide the spacecraft."
A Progress cargo ship that blasted off Sunday is scheduled to dock Tuesday, bringing fuel and supplies for the crew.
Valery Lyndin, a mission control spokesman, said that leaving the station unmanned would be hazardous because there would be no crew to spot and fix problems.
Semyonov said Russia will consult with its partners on revisions to the flight schedule. He said Russia had planned to send another space tourist to the station in April, but would now drop the idea.
Mikhail Sinelshchikov, a Russian space agency official in charge of the manned space program, said Monday that Russia would stop sending paying tourists and crews on short-term visits to the station while shuttle flights are suspended.
In the past, U.S. shuttles have ferried long-term crews to the 16-nation space station, while Russian rockets have carried visiting crews in fresh Soyuz craft that they leave behind as emergency escape vehicles. An American and a South African have paid a reported $20 million each to fly to the space station aboard Russian rockets.