President Bush is wishing the crew of the Space Shuttle Discovery a safe and successful mission. Tuesday's launch is the first U.S. manned space flight since the Shuttle Columbia burned-up on re-entry in 2003.

Like many Americans, President Bush stopped what he was doing Tuesday morning and watched on television as the Space Shuttle Discovery rose into the sky over Florida.

Watching from a private dining room off the Oval Office, White House Spokesman Scott McClellan says President Bush applauded the successful launch and reflected on what an exciting day it is for all Americans.

"Our space program is a source of great national pride, and this flight is an essential step toward our goal of continuing to lead the world in space science, human space flight and space exploration," said Mr. Bush.

Mr. McClellan says the president gave thanks to the men and women of the U.S. space agency who have dedicated themselves to putting the space program back on track following the loss of the Columbia crew two years ago.

President Bush says the space agency's long-term mission is to land astronauts on Mars. He wants scientists to build a base on the Moon as a staging-area for a Mars mission.

Critics say the costs of a mission to Mars will undercut funding for scientific experiments on the international space station and necessary maintenance on the Hubble space telescope.