The shuttle rose from its seaside pad under tight post-Sept. 11 security, carrying six astronauts and a 14-ton girder that will be installed on the international space station later this week.
The launch marked the debut of the shuttlecam, a color video camera mounted near the top of Atlantis' external fuel tank. The camera beamed down live images as the shuttle soared out over the Atlantic.
The camera developed by CrossLink Incorporated of Boulder, Colorado will film the first 30 minutes of its flight.
NASA also had to scramble late in the countdown to replace a couple fuses in a backup power supply on the aging launch platform.
Although it was raining and lightning advisories were in effect as the astronauts headed to the pad early in the afternoon, the sky quickly cleared.
"Atlantis is ready for you," launch director Mike Leinbach told the astronauts just before liftoff. "The weather is beautiful, and you guys have been in Florida far too long. So we wish you luck."
The Air Force chased after at least six stray planes. Fighter jets patrolled the wide no-fly zone around the pad, to guard against a possible terrorist attack.
NASA solved a heating problem in a critical water-drainage line earlier in the day before the launch of space shuttle Atlantis, delayed 1 1/2 months because of cracked fuel lines and a hurricane.
A little before sunrise, the National Aeronautics and Space Administration began fueling Atlantis for the first shuttle flight since June.
The on-board heater was running at too high a temperature Sunday, and engineers scrambled to evaluate the impact on the 11-day mission to add onto the international space station. If the temperature in the line were to spike dramatically, equipment could be damaged, possibly even Atlantis' electricity-producing fuel cells.
A red team dispatched to pad 39B overnight successfully resolved problems with a gaseous nitrogen heater in a ground system, NASA spokesman George Diller said, reports CBS News Space Analyst William Harwood.
Diller said engineers managed fixed the problem and came up with a workaround plan.
The trouble was with one of three lines used to flush out water that is a byproduct of Atlantis' fuel cells. The heater for this backup line, needed to prevent a freeze-up, appeared to be on the wrong setting because of a bad controller. Replacing the controller would have meant a delay of several days.
The space shuttle should have blasted off in August, but was grounded along with the rest of the fleet by hairline cracks in the pipes carrying hydrogen fuel to the main engines. Then, Hurricane Lili threatened Mission Control last week, forcing the unprecedented shutdown of the Houston control rooms.
Mission Control was back in operation by Sunday and everything finally seemed to be falling into place — until the heater acted up.
If water backed up in the line, Atlantis' fuel cells could become saturated and shut down. Without adequate electricity, the shuttle probably would not have enough power to make an emergency landing.
The space station and its three occupants were soaring 240 miles above the Pacific, west of the Galapagos Islands, when Atlantis finally took off at 3:46 p.m. The shuttle should reach the orbiting outpost on Wednesday with goodie bags of apples, oranges, grapefruit, garlic, onions, hot sauce and a pecan pie.
Astronaut Peggy Whitson, the lone American aboard the space station, is tired of eating out of cans after four months in orbit and put in an order for fresh and spicy food. She has one month remaining in her mission.
During their week at the space station, Atlantis' astronauts will conduct three spacewalks to hook up the $390 million girder. It measures 45 feet long and 15 feet wide and is crammed with wiring, plumbing, three radiators and a railroad cart.
CBS News Space Consultant William Harwood has covered America's space program full time for more than 15 years, focusing on space shuttle operations, planetary exploration and astronomy. Based at the Kennedy Space Center in Florida, Harwood provides up-to-the-minute space reports for CBS News and regularly contributes to Spaceflight Now and The Washington Post.