Space station commander Kenneth Bowersox made his first public statements since the Columbia disaster during a radio exchange with former President George Bush and first lady Barbara Bush, who offered their encouragement.
"We're thinking about you and very, very proud of what you're doing," Barbara Bush echoed.
The short conversation took place after the Bushes were given a brief update on the Columbia investigation during a visit to NASA's Johnson Space Center in Houston, where the Bushes live.
"We're all doing fine up here. We're sad at the loss of our friends, but we're also concerned about all of you on the ground, the way you're reacting," Bowersox said. "We know that everyone down there shares a lot of pain. We believe we're going to be able to succeed and carry on."
The senior Bush was vice president when the space shuttle Challenger exploded seconds after liftoff from the Kennedy Space Center in 1986, killing its crew of seven.
The latest space station crew arrived in November and had been scheduled to return to Earth next month. But with the shuttle fleet grounded after Columbia's accident, they might remain in orbit until June. An unmanned supply ship is due at the station today. NASA said the space station crew was told about Columbia on Sunday.