The space shuttle Atlantis lifted off at 9:30 am Friday from Cape Canaveral, Fla. on a clandestine mission that anonymous sources said might be deploying a satellite.
These sources say the satellite, named Lacrosse, can form radar images of key Soviet military sites. US intelligence officials could use the information to confirm Soviet compliance with arms control treaties and to help guide the new B2 stealth bomber.
The US Department of Defense has classified the mission of the 27th shuttle flight as top secret.
Strong winds along the shuttle's flight path caused NASA to postpone the launch, which was originally scheduled for Thursday. "The winds would have put too much dynamic stress on the shuttle," NASA spokesman Pat Philipps said.
A leaky tank in the ground system caused a further delay Friday. NASA temporarily halted fueling and sent out a special team to tighten a fitting on an oxygen tank.
Navy Commander Robert L. Gibson, the Atlantis crew commander, sat through seven postponements of the shuttle Columbia's liftoff in 1986. Other crew members include Lt. Col. Guy S. Gardner, Col. Richard M. Mullane, and Lt. Col. Jerry L. Ross of the Air Force, and Navy Commander William M. Shepherd. Gardner and Shepherd are on their first shuttle mission. The others have flown before.
"A very clean ascent for Atlantis; there were no problems encountered on the way to orbit," said Brian Welch, commentator at Mission Control in Houston said. The two solid fuel booster rockets successfully burned out two minutes and eight seconds into liftoff. Failure of a booster rocket joint caused the Challenger's destruction in 1986.
After Welch announced that the vehicle was in very clean shape, the Defense Department stopped publicly broadcasting conversations between the crew and ground control for security reasons.
Four hours into the flight, NASA reported that "all systems of the orbiter are performing satisfactorily." The next report will come 24 hours before Atlantis lands at Edwards Air Force Base, Calif. The government did not reveal the duration of the flight, but it is expected to last three to five days.