Space shuttle Atlantis lifts off from pad 39B. Photo: NASA TV/Spaceflight Now

The shuttle Atlantis dodged coastal showers and blasted into orbit today, setting off after the international space station and kicking off the most ambitious shuttle launch schedule since the pre-Challenger era.

With commander Terrence Wilcutt and pilot Scott Altman at the controls, Atlantis blasted off on time at 8:45:47.066 a.m. EDT (0845:47.066 GMT), the precise moment Earth's rotation carried pad 39B into the plane of the space station's orbit.

"We have booster ignition and liftoff of the space shuttle Atlantis, opening the door to a permanent human presence in space," said NASA commentator Bruce Buckingham as Atlantis roared away.

Joining Wilcutt and Altman aboard the veteran shuttle were Edward Lu, Richard Mastracchio, Daniel Burbank and two Russian cosmonauts, Mir-veteran Yuri Malenchenko and physician Boris Morukov.

With its twin solid-fuel boosters spewing fire and thunder, Atlantis majestically climbed skyward and arced east over the Atlantic Ocean, disappearing behind off-shore clouds as it raced away up the East Coast of the United States. Eight-and-a-half minutes later, Atlantis slipped into its planned preliminary orbit.

At the moment of liftoff, Atlantis's unmanned quarry - the space station - was passing above Hungary near the Croatian border some 6,600 miles ahead of Atlantis.

The shuttle rises behind a cloud of stream from the main engines. Photo: NASA TV/Spaceflight Now

Over the next two days, Wilcutt and Altman will carry out a series of carefully timed rocket firings to catch up with the space station for a docking shortly after 2 a.m. EDT Sunday.

After a spacewalk Monday to connect electrical and data cables between the new Russian command module Zvezda and the rest of the station, the astronauts will spend at least five days moving equipment and supplies into the lab complex and activating critical life support systems.

If all goes well, the station's first full-time crew will arrive in early November and from that point forward, the orbital laboratory will be permanently staffed.

"We are going to have a world-class laboratory on orbit with a permanently manned presence in the very, very near future," said veteran shuttle commander Robert Cabana, a senior space station manager. "And it's going to be something spectacular."

Over the next 12 months, NASA plans to launch nine shuttle missions - eight of them devoted to space station assembly - tying a single-year launch record set in 1986. At that time, NASA planned to launch 16 missions in 1986, but the schedule was cut short by the Challenger disaster.

Building the million-pound $60 billion space station is "going to be as complex and difficult as anything we've ever done at NASA, including landing a man on the moon," said shuttle program manager Ron Dittemore. "It offers different challenges, but it's extremely complex."

Atlantis rolls on course for a 51.6-degree inclination orbit, heading northeast from Kennedy Space Center. Photo: NASA TV/Spaceflight Now

Added station program manager Tommy Holloway: "I sort of feel like a father - maybe that's really a grandfather - that's expecting triplets or something. It's really (a time of) great expectations. Very shortly, the space station's going to come to life and literally be born."

The 99th shuttle mission follows the successful but long-delayed launching of the Russian command module, Zvezda, in July and a Progress supply ship in August, kicking off the most ambitious 12 months of U.S.-Russian launch activity in station history.

"Beginning with the Zvezda launch a few weeks ago, we're beginning a year in which we should have about 15 launches, which is the most intense period of flight operations human spaceflight has ever undertaken," said James Vaan Laak, deputy space station program manager.

"We're very excited about that, but I think we're all very awed by the challenge it represents."

Atlantis will lock itself to a pressurized mating adaptor, or PMA, attached to one end of the multi-hatch Unity node, launched by NASA in December 1998. At the other end of the Unity module is another PMA that connects to the Russian-built NASA-financed Zarya propulsion module, launched in November 1998.

Zarya, in turn, is attached to Zvezda and the Progress 251 supply ship is docked to a port at the far end of the new command and crew module. Once docked, the 128,000-pound (58,000 kilogram) space station will tower some 130 feet (40 meters) above Atlantis's cargo bay.

A shockwave forms on the shuttle as it climbs to orbit. Photo: NASA TV/Spaceflight Now

The astronauts will not immediately enter the station or even open any hatches. First, Lu and Malenchenko are scheduled to stage a six-and-a-half-hour spacewalk early Monday to connect four power cables between Zarya and Zvezda and four video and data cables.

The spacewalkers also plan to hook up a fiber optic telemetry cable that will be used during future Russian spacewalks and re-position an orientation-sensing magnetometer on an extended boom near the rear of Zvezda.

"When they're working on the magnetometer boom, they'll be about 110 feet away from the space shuttle, which is twice as high as astronauts were when we worked on the top of the Hubble Space Telescope," said Mike Hess, a NASA spacewalk planner. "It'll be the equivalent of working on about the 11th story of a 13-story building."

Once the spacewalk is complete, the astronauts will float into the space station Monday evening to begin transferring supplies and equipment into the outpost. The goal is to outfit and activate the Zvezda module, which will provide the station's initial crew quarters and the propulsion needed to maintain a safe orbit.

To save weight, Zvezda was launched with many of its modular life support and control systems incomplete.

The twin solid rocket boosters separate to fall into the Atlantic Ocean. Photo: NASA TV/Spaceflight Now

The Progress 251 vehicle launched Aug. 6 and now docked to Zvezda's aft port, is loaded with some 1,313 pounds (588 kilograms) of gear, including components for an Elektron oxygen generator, a carbon dioxide air scrubber, laptop computers and components for the station's toilet.

Atlantis will carry another 4,817 pounds (2,186 kilograms) of supplies and equipment, including 722 pounds of Russian hardware, 858 pounds of food, 784 pounds of fresh water generated by the shuttle and 1.150 pounds of exercise equipment.

Two new batteries will be installed in the Zarya module - four were replaced during the most recent shuttle visit in May - and three batteries and their charge-discharge controllers will be installed aboard Zvezda, giving the module a full complement of eight.

Atlantis's crew will be hard pressed to completely unload both vehicles during the five days Atlantis is docked to the station and NASA managers are holding open the option of extending the mission by one day if power and propellant margins permit.

Assuming the flight is, in fact, extended one day, Atlantis will return to Earth two hours before dawn on Sept. 20.