The shuttle Discovery glided to a smooth dawn touchdown Wednesday to wrap up a near-perfect flight, leaving the Ulysses probe behind in space on a quest to study the uncharted poles of the sun.

With skipper Richard "Dick" Richards, 44, and co-pilot Robert Cabana, 41, at the controls, Discovery gracefully swooped out of the morning sky, settling onto concrete runway 22 on 6:57 a.m. with swirling puffs of blue smoke from its main landing gear tires.Barreling down the runway at some 200 mph, Richards pumped Discovery's beefed-up carbon brakes to bring the 100-ton orbiter to a stop in the final test of a four-day 65-orbit flight covering some 1.7 million miles since blastoff Saturday.

"Wheels stopped, Houston," Richards radioed mission control.

"Copy, wheels stopped, Discovery; The rest of your team is glad to have you back," said astronaut Brian Duffy from Houston. "Congratulations on a picture-perfect mission."

Richards, Cabana, flight engineer William Shepherd, 41, Bruce Melnick, 40, and Thomas Akers, 39, planned to fly back to their homes in Houston near the Johnson Space Center about six hours after landing.

Before re-entry, the astronauts received greeting from U.S. forces in the Middle East in a message faxed to the spaceship from mission control.

"Yours has been a most successful space mission in the continuing search for answers to make the world a safer and better place to live. Here on the Earth, we strive to ensure the same results. We salute you on a job well done - and happy landings," the message said.

Officials said Tuesday Richards and company had chalked up a near-perfect flight, a welcome shot in the arm for the beleaguered space agency after a summer of repeated shuttle launch delays and near-constant criticism over problems with the flawed Hubble Space Telescope.

The astronauts accomplished the primary goal of the 36th shuttle mission, NASA's first in nearly six months, when they successfully deployed the nuclear-powered Ulysses probe Saturday on a $750 million flight over the poles of the sun.

While Ulysses is not equipped with a camera, and while its orbit will never carry it closer than about 120 million miles to the sun, its instruments will give astronomers their first three-dimensional glimpse of Earth's star, its complex magnetic field and the tenuous solar wind.

If all goes well, Ulysses will begin a four-month pass over the sun's south polar region in May 1994. A similar pass over the north polar region is planned for 1995.