The Proton rocket roars away from the Baikonur Cosmodrome under the power of its six first stage engines roar to life. Photo: NASA

Running two years behind schedule, a heavy lift Proton rocket finally boosted the Russian Zvezda command module into orbit early today, opening a floodgate of stalled U.S.-Russian assembly missions. If all goes well, Zvezda will dock with the space station July 25 and the first full-time crew - a U.S. commander and two Russian cosmonauts - will float aboard in early November to begin full-time occupation of the orbital outpost.

From that point forward, humanity will have what NASA hopes will be a permanent settlement on the final frontier.

The 20-ton Zvezda - the Russian word for "star" - will serve as the station's command center, providing crew quarters, communications, power distribution, data management and the propulsion needed to keep the lab at the proper altitude.

Zvezda, in short, will be the backbone of the international station during the initial phases of assembly, clearing the way for NASA to launch a half-dozen major components over the next year that have been held up by Zvezda's long delay getting into orbit.

The milestone mission began at 12:56:36 a.m. EDT (4:56:36 GMT) when a heavy lift Proton rocket, built by the Krunichev State Research and Production Center in Moscow, roared to life, shattering the morning calm at the Baikonur Cosmodrome in Kazakhstan. The towering rocket quickly climbed away from its firing stand, arcing to the east through a slightly hazy sky as it thundered skyward.

"... four, three, two, one and liftoff, we have engine ignition and liftoff of the Proton rocket carrying Zvezda, the centerpiece of Russia's contribution to the international space station, setting the stage for permanent human presence in space," said NASA launch commentator Kyle Herring in the Russian mission control center near Moscow.

Emblazoned on the side of the rocket was a huge Pizza Hut logo, an all-too-visible reminder of the once vaunted Russian space program's dependence on foreign capital for critical funding.

Whatever NASA's discomfort at the commercial aspects of today's launch, the Proton's three stages appeared to work as advertised, including the four engines powering the rocket's second stage. Second stage engine malfunctions doomed two Proton's last year and an unexplained second stage fuel pressurization drop during launch of a modified Proton July 5 had NASA managers on the edges of their seats today.

Proton, sporting a Pizza Hut logo climbs away from pad 23 at Baikonur Cosmodrome in Kazakhstan with Zvezda. Photo: Pizza Hut

But to their collective relief, there were no apparent problems this time around and Zvezda was released into its planned preliminary orbit nine minutes 47 seconds after launch.

"The launch this morning was apparently flawless," said Herring. "By all accounts the climb to orbit using the Proton rocket was without incident. Zvezda, the service module, now on its own."

NASA Administrator Daniel Goldin, who watched the launch at Baikonur with other senior U.S. and Russian managers, grinned, gave a hearty thumbs up and began congratulating his companions when word of spacecraft separation was received. A few minutes later, Zvezda's two solar arrays unfolded, providing electrical power to recharge the module's batteries.

"And at 15 minutes 40 seconds into the flight, we now have received confirmation of both solar arrays being deployed on the Zvezda service module," Herring reported. "Those solar arrays stretching the wingspan of the module to about 30 meters, or 95 and a half feet. Telemetry on the ground showing the module is in excellent shape."

A news conference to discuss the launching will be carried live on NASA television at 2:30 a.m.

It will take flight controllers two full weeks to activate and check out Zvezda's systems and to maneuver the spacecraft into the proper orbit and orientation for docking with the international space station. For the final rendezvous and docking, Zvezda will play a passive role while the Russian-built NASA-financed propulsion module Zarya drives the space station gently into a linkup with Zvezda (see the mission preview below for complete details).

The first item on the agenda today is to activate the service module's guidance and control systems and to analyze telemetry to assess the health of the spacecraft. Main engine test firings are planned on flight day two "to make sure everything's looking good there," said NASA flight director Mark Ferring. Russian flight controllers also will assess solar array efficiency and use star trackers for the first time to determine Zvezda's position in space.

Early Friday morning (Eastern time), flight controllers plan to carry out the first of two sets of major rocket firings. This so-called "interval one" set of firings will put Zvezda in roughly the same orbit as the space station at an average altitude of roughly 222 miles. That is where the space station will be in two weeks as a result of natural braking forces produced by passage through the extreme upper atmosphere.

The Proton rocket completes pitch and roll maneuvers to align itself with the proper launch trajectory. The six engines are clearly visible. Photo: NASA

Depending on Zvezda's initial orbit, the service module may be boosted to a less ambitious 217 miles or so. In that case, the space station's rockets would be used to lower its altitude, meeting the new module halfway, so to speak. Either way, small rocket firings to fine-tune Zvezda's orbit will be carried out Saturday. At the same time, engineers will begin testing the module's Regul communications system.

"That's a relatively new command and telemetry system for them," Ferring said. "That was installed on the Buran space shuttle vehicle but it has not been used in any other program. So they're going to do an extensive test of the Regul system in orbit."

Flight days five through nine will be devoted to testing Zvezda's navigation system, its batteries, black-and-white television cameras and the rendezvous systems that will be used during final approach to the space station. On flight day 10, engineers will test the module's new solar arrays in a different command mode, switching from a course "solar sensing" sun-tracking mode to a more precise format that will track the sun based on the station's actual orientation in space.

"This is important because it's a lot more efficient method of producing power," Ferring said. "In solar sensing mode, when you go into eclipse when there's no sun, the solar arrays just stop tracking. When you pick up the sun on the other side of the orbit, they're pointing in the wrong direction and it has to slew back the other way. So you lose quite a bit of time for producing power."

After testing the docking systems on Zvezda and the space station, Russian flight controllers plan to fire the service module's main engines again July 23 to set up the final rendezvous, setting the stage for docking around 8:44 p.m. EDT on July 25 (0044 GMT on 26th).