BY SPACEFLIGHT NOW

July 21, 2000 -- Follow the flight of the Zvezda module as it heads for a rendezvous and docking with the international space station. Reload this page for the very latest on the mission.

MONDAY, JULY 17, 2000

NASA says the Zvezda service module is working fine as it remains bound for a docking with the International Space Station on the evening of July 25.

Over the weekend, Russian flight controllers finished checking out the 'Regul' telemetry system, which involved cycling through various software modes to ensure good command links from the ground, and analyzing the return link from the module.

No activity was performed Sunday, which was the first of three days set aside for troubleshooting, if required.

Earlier today, controllers tested the module's motion control and navigation system using onboard sun sensors. Last week the system was tested using the star sensors. These tests verified the full operation of the onboard software to manage Zvezda's guidance system. Also today, routine cycling of the five batteries began. The module was launched with five of eight batteries installed. The remaining three will be delivered and installed during the next Space Shuttle visit scheduled for September.

FRIDAY, JULY 14, 2000

The Zvezda service module on Friday moved ever closer to next week's rendezvous and docking with the international space station. Zvezda, successfully launched on Wednesday by a Russian Proton rocket, conducted a pair of engine firings to raise its orbit. The burns were performed two engines located on the back end of the module.

With Zvezda flying in an attitude with the forward end pointing in the direction of travel, the first burn was carried out at 1:09 a.m. EDT (0509 GMT), raising the orbit to 222 by 114 miles (358 by 183 km).

The second burn 45 minutes later at 1:44 a.m. EDT (0544 GMT) boosted Zvezda to an altitude of 224 by 167 miles (361 by 269 km).

Docking with the Zarya module of the international space station remains scheduled for July 25 at 8:46 p.m. EDT (0046 GMT on the 26th).

As is the case with any firing of the reboost engines, the solar arrays were positioned to minimize the effects of vibrations through the structure. After the burns, the solar arrays were moved back to their normal operating positions.

In addition to the rendezvous burns, the only other planned activity for the day was to verify the accuracy of the solar array drive motors in the backup mode. That was done by analyzing telemetry data gathered on each available communications pass through Russian ground stations.

The correction burn planned for Saturday was cancelled after Russian flight controllers analyzed the results from today's burns and determined no adjustment to Zvezda's orbit was required.

The only scheduled activity over the weekend is a thorough checkout of the "Regul" telemetry system that includes the receiver/transmitter, antenna and onboard computer. The test will involve cycling through various software modes to ensure good command links from the ground while analyzing the return link from the module.

Telemetry from the module continues to show that sensors are not detecting the deployment of a docking target that only would be required if a manual docking were needed. This will not affect the planned automatic docking July 25. As a reference point, Zvezda and the Zarya control module on the ISS use the same rendezvous hardware as on the Mir space station and all of its modules docked automatically.

Zvezda attitude control is being maintained by 16 of its 32 small control thrusters. The 32 thrusters, which produce 29 pounds of thrust each (roughly equivalent to the vernier jets on a space shuttle orbiter), are divided equally between two manifolds. Only manifold one is being used.

THURSDAY, JULY 13, 2000
1444 GMT (10:44 a.m. EDT)

All continues to go well aboard the Zvezda module. NASA sources have provided additional information on the possible TORU problem that cropped up yesterday.

Data radioed from Zvezda indicates pyrotechnics fired to release one of two TORU reflectors shortly after launch, but Mission Control never received confirmation it locked into space, sources said.

Russian officials believe a sensor or telemetry problem could be to blame, creating a false indication that the reflector is stuck.

Even if the reflector did not deploy, it should have no immediate impact with the module's link up with the space station since the TORU system is the backup docking system. The primary system -- the Russian automated rendezvous and docking system or KURS -- is reported healthy following the launch.

The Teleoperated Rendezvous Control System would be used by cosmonauts to manually connect Zvezda with the international space station should the automatic system fail.

WEDNESDAY, JULY 12, 2000
2115 GMT (5:15 p.m. EDT)

Russian and American flight controllers report Zvezda's first hours in space have gone very smoothly. In fact, officials are considering removing three days of contingency time originally built into the module's pre-docking schedule, sources say. If approved later this week, the new plan would see Zvezda dock with the international space station on July 23.

The only issue of note this afternoon is the possibility one of TORU's RF docking antennas might not be locked in its deployed position. The Teleoperated Rendezvous Control System would be used by cosmonauts to manually connect Zvezda with the international space station should the automatic system fail.

Otherwise Zvezda is in good shape with initial systems checks showing acceptable readings. The next significant milestones will be a pair of verification burns of the module's thrusters early tomorrow.

1025 GMT (6:25 a.m. EDT)

Russian flight director says Zvezda in good shape. William Harwood filed this report:

All of the Zvezda command module's solar arrays and antennas successfully deployed shortly after the spacecraft reached orbit today and chief flight director Vladimir Solovyev said no problems of any significance had been encountered during the module's initial orbits.

"Insertion went without any problems, there were no anomalies, all systems worked fine and all external elements were deployed," he said at a news conference. "We're happy, we checked out the attitude and no reboosting is required. We're happy with the dynamics of insertion."

Bob Castle, a NASA flight director observing the mission from the Russian control center near Moscow, congratulated his Russian colleagues on the successful launch.

"This is a key element of the international space station," he said. "The key element in my mind, because it allows us to put a crew aboard the station, something that we must do to continue the build up of the space station. It was good to hear the words of Vladimir Solovyev of how well the checkout is going."

Frank Longhurst, space station program manager for the European Space Agency, reported that Zvezda's German-built computer system was operating normally with no problems of any significance.

On a more sobering note, Yuri Grigoriev, deputy general designer with Zvezda-builder RSC Energia, said "due to lack of funding ... we'll have to change our plans" in the future.

"In the year 2000, we see no major problems," he said through an interpreter. "After docking of the service module, we plan to launch three or four vehicles, one Soyuz and two or three Progresses. This year looks OK. Speaking of the following year, in 2001, we plan to launch eight vehicles and I must say we have great problems with the funding and paying for construction of space vehicles. In the coming two months we'll try to resolve those issues together with the Russian Aerospace Agency.

"Then in the first quarter of the next year, we are planning to launch a Russian module, an airlock-pressurized docking module. And speaking of another seven or eight elements, unfortunately i have to say the works on those modules, those works are frozen. And so the program of the Russian segment of the international space station should be reconsidered and we should revise our plans and make adjustments."

0610 GMT (2:10 a.m. EDT)

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. Read our full story.

Also check out a QuickTime video clip of the launch.

0512 GMT (1:12 a.m. EDT)

The two power-generating solar arrays have been deployed from the Zvezda service module, which is now orbiting the Earth after an apparent smooth launch by the Proton rocket. The arrays give the module a wing span of 95 feet, tip-to-tip, and collect sunlight to recharge onboard batteries.

We will pause our coverage at this point. However, check back for a video clip and full story. Also, we will provide reports over the next two weeks as Zvezda heads for a rendezvous and docking with the international space station.

0511 GMT (1:11 a.m. EDT)

Solar array deployment aboard Zvezda now beginning. This will take about a minute to complete.

0509 GMT (1:09 a.m. EDT)

The KURS automatic docking system antennas are being deployed. Data from Zvezda shows the deployment beginning with pyrotechnic pins being fired.

0508 GMT (1:08 a.m. EDT)

Over the next few minutes Zvezda's solar arrays will be deployed.

0507 GMT (1:07 a.m. EDT)

T+plus 10 minutes. SPACECRAFT SEPARATION! The Proton rocket's third stage has completed its job today and released the Zvezda service module in orbit to serve as the home for future residents aboard the international space station.

0505:36 GMT (1:05:36 a.m. EDT)

T+plus 9 minutes. The third stage engine on the Proton rocket still firing to deliver Zvezda into low-Earth orbit. Engine cutoff is expected in 37 seconds and deployed of the module should follow 10 seconds later.

0504:36 GMT (1:04:36 a.m. EDT)

T+plus 8 minutes. Just over 90 seconds remaining in powered flight today for the Proton rocket. All continues to go very smoothly, NASA says.

0503:36 GMT (1:03:36 a.m. EDT)

T+plus 7 minutes. Data indicates the third stage engine is burning as expected. The pressures in the stage's fuel tank reported normal.

0502:36 GMT (1:02:36 a.m. EDT)

T+plus 6 minutes. The Proton rocket's second stage has been separated. Standing by for confirmation the single third stage engine is firing. Officials report the motion control system indicates a very stable rocket.

Also, Zvezda's onboard data recording system should be active.

0501:36 GMT (1:01:36 a.m. EDT)

T+plus 5 minutes. About 35 seconds remaining in the second stage burn for Proton.

0500:36 GMT (1:00:36 a.m. EDT)

T+plus 4 minutes. The Proton rocket's payload fairing, or nose cone, has been jettisoned. Several communications antennas on Zvezda are now being deployed.

0459:36 GMT (12:59:36 a.m. EDT)

T+plus 3 minutes. Good pressures reported in the second stage fuel tanks. The stage's four engines continue fire.

0458:06 GMT (12:58:06 a.m. EDT)

T+plus 2 minutes, 30 seconds. Confirmation of first stage engine cutoff and separation of the spent stage. The second stage engines have ignited.

0458:06 GMT (12:58:06 a.m. EDT)

T+plus 90 seconds. The Proton rocket's six first stage engines still firing. Engine cutoff and staging will occur in just under 40 seconds.

0457:36 GMT (12:57:36 a.m. EDT)

T+plus 1 minute. All systems reported nominal aboard the Proton rocket.

0457:06 GMT (12:57:06 a.m. EDT)

T+plus 30 seconds. First stage performance reported normal. Pitch and roll programs have started.

0456:36 GMT (12:56:36 a.m. EDT)

LIFTOFF! Liftoff of the Russian Proton rocket launching the Zvezda service module -- creating a new home in space for humankind.

0455:36 GMT (12:55:36 a.m. EDT)

T-minus 1 minute and counting. Now 60 seconds from the historic launch of the Zvezda service module -- the initial crew living quarters for the international space station.

0455:06 GMT (12:55:06 a.m. EDT)

T-minus 90 seconds counting.

0454:36 GMT (12:54:36 a.m. EDT)

T-minus 2 minutes and counting. Ground recorders have been turned on to collect data during Proton's climb to orbit. All systems remain go for liftoff.

0453:36 GMT (12:53:36 a.m. EDT)

T-minus 3 minutes and counting. VIPs have gathered at the observation deck a few kilometers from the launch pad at Baikonur Cosmodrome.

Officials report Proton's control systems are verified ready for launch and the vehicle's steering jets are positioned for flight.

0452:36 GMT (12:52:36 a.m. EDT)

T-minus 4 minutes and counting. Onboard telemetry monitoring systems going to internal power for launch.

0451 GMT (12:51 a.m. EDT)

T-minus 5 minutes and counting. The final launch operations program is being initiated at this point in the countdown. Liftoff remains scheduled for 0456:36 GMT (12:56:36 a.m. EDT).

0446 GMT (12:46 a.m. EDT)

T-minus 10 minutes and counting. Ground support systems are now being verified ready for launch by Russian officials. Also, Zvezda will shortly switch from ground-fed power to its onboard batteries.

0441 GMT (12:41 a.m. EDT)

T-minus 15 minutes and counting. It will take the three-stage Proton rocket just shy of ten minutes to deliver the Zvezda service module into the planned orbit around Earth. See our launch timeline for a complete description of the events slated to occur.

Also at this time, Zvezda's telemetry monitoring system has gone active. This system will allow ground controllers the opportunity to oversee the other environments around the module during launch.

0436 GMT (12:36 a.m. EDT)

Now 20 minutes away from the launch of Zvezda bound for the international space station. The countdown is being controlled by the launch sequencer, which is programmed with the planned 0456:36 GMT (12:56:36 a.m. EDT) liftoff of the Proton.

In the past few minutes, the thermal control system was activated, the Motion Control System was turned on in its pre-launch mode and the final alignment of gyroscopes for the required launch azimuth occurred.

Also, fine tuning of the gyro-stabilized launch platform of the Proton's trajectory control system began.

0430 GMT (12:30 a.m. EDT)

Countdown activities are proceeding on schedule at Baikonur Cosmodrome's pad 23 as the Russian Proton rocket is readied for liftoff. Officials have announced the revised launch time based upon the latest tracking of the international space station's orbit. Liftoff is now slated for 0456:36 GMT (12:56:36 a.m. EDT).

Over the last several hours, the Proton's three stages were loaded with their supplies of nitrogen tetroxide oxidizer and Unsymmetric Dimethyl Hydrazine fuel. The service gantry was then retracted.

At this point there are no problems being reported and weather conditions are not a concern.

0400 GMT (12:00 a.m. EDT)

At long last, launch day has finally arrived for the Russian-made Zvezda service module, the next critical element of the international space station. The importance of tonight's launch -- now 56 minutes away -- cannot be overly exaggerated. The near-term future of human spaceflight rests atop the Russian Proton rocket at the Baikonur Cosmodrome in Kazakhstan.

Without Zvezda, long-duration stays by astronauts aboard the space station will not be possible any time soon. In addition, Zvezda is the key to continuing the next five years of constructing of the $100 billion research laboratory in the sky.

This launch day has been delayed for two years due to Russia's economic woes put the module's construction behind schedule. But now all appears in readiness as the Proton rocket sits fueled and ready for liftoff at 0456 GMT (12:56 a.m. EDT) today.

TUESDAY, JULY 11, 2000
1830 GMT (2:30 p.m. EDT)

Russian launch controllers are readying a powerful Proton rocket for blastoff at 0456:28 GMT (12:56:28 a.m. EDT) Wednesday from the Baikonur Cosmodrome in Kazakstan on a make-or-break flight to ferry the long-delayed Zvezda command module into orbit. Zvezda will serve as the central command center of the international space station, providing crew quarters and the propulsion necessary to keep the lab complex in orbit.

Forecasters are predicting low clouds and scattered showers at the Baikonur launch site with 20- to 30-knot winds expected by noon local time. But conditions are expected to be well within the unmanned Proton's launch constraints and there are no known technical problems that would delay liftoff.

Zvezda's launching marks a critical milestone for the international space station program. Zvezda is running two years behind schedule because of Russian funding problems and a successful launch, rendezvous and docking July 25 will open a floodgate of station assembly missions.

"It's ... the beginning of the real assembly of the international space station with 15 launches scheduled in the next calendar year," said Michael Baker, a veteran shuttle commander who serves as NASA's chief of operations in Russia. "There will be eight shuttle flights, five Progress flights and two Soyuz flights. And of course, the first crew will launch in late October, the first of November, to begin permanent human habitation."

If Zvezda fails to reach orbit, however, completion of the space station would be delayed at least three years. And that doesn't take into account the inevitable political fallout in a presidential election year. Whatever the outcome, there appears little doubt the future of the space station project rides on the outcome of Wednesday's launch.

Two Proton's failed last year when their second stage engines malfunctioned. Modifications were made and two Proton's -- one launched June 6 and the other July 5 -- successfully delivered satellite payloads to orbit.

But the most recent Proton suffered an anomaly during the climb to space last week and it is still not clear exactly what went wrong. Telemetry indicated an unexpected drop in the fuel repressurization system of the rocket's second stage. The anomaly had no effect on the rocket's overall performance and engineers with rocket-builder Krunichev say inspections and data analysis show Zvezda's Proton is healthy and ready for flight.

But the incident and uncertainty about the details have raised the anxiety level of NASA managers in the uncomfortable position of sitting on the sidelines during one of the most important launches of the space station program. Zvezda and its Proton rocket were built and paid for by Russia and NASA played no role in the decision to clear Zvezda's Proton for launch.

0900 GMT (5 a.m. EDT)

With less than 24 hours until the launch of the Zvezda service module atop a massive Proton rocket, Russian space technicians are making final preparations at Baikonur Cosmodrome's pad 23 for tonight's countdown. Liftoff remains scheduled for 0456:28 GMT (12:56:28 a.m. EDT) Wednesday.

Countdown activities will get underway in earnest at T-minus 8 hours, or 2056:28 (4:56:28 GMT) this afternoon, as the rocket's avionics are powered up and verified in good condition. About 40 minutes later Zvezda's command and control systems heaters will be turned on.

At T-minus 7 hours Zvezda's telemetry system will be powered on to provide ground controllers a window of opportunity to verify the module's onboard systems. Data recorders are started at this time, too. About 30 minutes later the telemetry system will be turned off and electric buses will be powered down.

Fueling of the three-stage Proton rocket is scheduled to commence at T-minus 6 hours, or 2256 GMT (6:56 p.m. EDT) as oxidizer begins flowing into the vehicle. This process will take two hours and 40 minutes to complete. Loading of propellant is expected to start at T-minus 4 hours, 20 minutes, or 0036 GMT (8:36 p.m. EDT), and take 70 minutes to complete.

A thermal conditioning process to prep Proton and Zvezda is scheduled into the countdown at T-minus 2 hours, 40 minutes, or 0216 GMT (10:16 p.m. EDT).

At launch pad 23 retraction of the service umbilical will occur at T-minus 70 minutes, or 0346 GMT (11:46 p.m. EDT). Also at that time, the cavities in Proton's propellant tanks will be ventilated and purged, the ground system electric bus will be activated and the launch sequencer will be programmed with the proper start time, which will be synchronized with Universal Time. Five minutes later the Proton's trajectory will be adjusted based on final updating.

With one hour prior to liftoff, the ground station data handling complex will be turned on and Zvezda's electrical buses and telemetry systems will be powered on for launch.

At T-minus 45 minutes, or 0411 GMT (12:11 a.m. EDT), Zvezda's launch sequence is initiated. Five minutes later the radio-telemetry system is activated.

The thermal control system goes active at T-minus 35 minutes, the Motion Control System is turned on in its pre-launch mode at T-minus 33 minutes, and the final alignment of gyroscopes for the required launch azimuth occurs at T-minus 32 minutes.

At 0431 GMT (12:31 a.m. EDT) at T-minus 25 minutes, fine tuning takes place of the gyro-stabilized launch platform of the Proton's trajectory control system in the horizon plane and line of the azimuth. The trajectory measurement system is activated five minutes later.

Zvezda's telemetry system goes activate at T-minus 18 minutes, and at T-minus 15 minutes, the onboard telemetry monitoring system starts and thermal monitoring of Proton's engines begins.

At T-minus 12 minutes, rotation of Proton's gyro-stabilized platform of the trajectory control system begins.

Ground systems will be verified ready at T-minus 10 minutes, or 0446:28 GMT (12:46:28 a.m. EDT). One minute later Zvezda switches from ground power to its onboard batteries.

At T-minus 8 minutes, steering jets on all Proton stages will be confirmed in the "zero position" for launch, ground command then receives "control systems ready" and "auxiliary systems ready" messages.

The final launch operation program is initiated at T-minus 5 minutes. A minute later the telemetry monitoring system switches to onboard power. Zvezda's telemetry system recording starts at T-minus 3 minutes, 30 seconds. Ground station recorders are powered on at T-minus 3 minutes.

At T-minus 2 minutes, ground command receives the "main block ready" command. At T-minus 1 minute, ground station recorders are started.

Ignition of the six engines on Proton's first stage begins at T-minus 2.5 seconds via a command from the time launch sequencer mechanism. Also at this time, Proton's control system switches to onboard power.

At T-minus 1.6 seconds, Proton commands the first stage engines to full thrust. Liftoff will happen at T-0, or 0456:28 GMT (12:56:28 a.m. EDT).

See our launch timeline for a chart and description of events to occur during the near-10 minute climb to orbit for Zvezda, the initial crew living quarters for the International Space Station.

Spaceflight Now will provide extensive live coverage during the final countdown and historic launch of Zvezda. Watch this page for ongoing reports and our live play-by-play description of the Proton's flight. In addition, we will offer a live QuickTime streaming video broadcast of the launch starting at 0430 GMT (12:30 a.m. EDT).

MONDAY, JULY 10, 2000

The stakes are literally sky high: Nothing less than the future of the international space station. That's what many believe is riding on Wednesday's launch of a long-delayed Russian command module called Zvezda. Read our story.

SATURDAY, JULY 8, 2000

The Russian Proton rocket, with the Zvezda service module loaded aboard, was transported via train from the vehicle assembly building to the launch pad Saturday in preparation for liftoff Wednesday morning.

The three-stage Proton was hauled horizontally to Baikonur Cosmodrome's pad 23 in remote Kazakhstan. Once at the launch complex, the rocket was erected vertically. While at the pad, a mobile service tower will enclose the Proton to provide access.

Launch activities are reported to be proceeding on schedule for liftoff at 0456:28 GMT (12:56:28 a.m. EDT) on Wednesday. The launch time will be refined based upon the radar tracking of the International Space Station.

FRIDAY, JULY 7, 2000
1140 GMT (7:40 a.m. EDT)

A senior official with the Khrunichev State Research and Production Center in Moscow said today an anomaly during launch of a Proton rocket July 5 was minor and would have no impact on plans to launch the Zvezda command module to the international space station July 12.

News reports in Russia about an apparent anomaly following a military Proton launch last Wednesday from the Baikonur Cosmodrome were "over dramatized," the Khrunichev official said, "but unfortunately, the public likes dramatic actions."

NASA sources said Thursday indications of low chamber pressure in at least one of the Proton's four second-stage engines were the result of a faulty sensor and not an actual hardware problem. At a news conference today, however, the Khrunichev manager, speaking through a translator, said there was, in fact, an actual drop in chamber pressure in the final moments of second stage operation.

"We've got a full understanding of the problem," he said. "It was a minor problem, we've never encountered such a problem before. Space Center Khrunichev is positive we'll have no problem with the launch (of Zvezda). We support the launch and the State Commission made the decision that the space rocket Proton is ready for launch of the service module from Baikonur."

Elaborating on the July 5 anomaly, he said "we did have below nominal pressure in the final stage of the second stage (firing), but it didn't affect the overall operation. The fact that the satellite was inserted into space and got into the right position is good proof it didn't affect the overall mission. It's not related to the modifications that were performed on the Proton launcher. It's a minor (issue) and it doesn't have an effect on the whole program."

He was referring to modifications ordered in the wake of two catastrophic Proton failures last year in which second stage malfunctions doomed two satellites. Since those failures, two Protons have been launched with unmodified second stage engines and two more with modifications supported by NASA.

The Zvezda module is scheduled for launch next Wednesday atop a modified Proton. The module has been fueled and attached to its Proton launcher and if all goes well, the spacecraft will be moved to its launch stand Saturday at the Baikonur Cosmodrome in Kazakhstan for final preparations.

"We are extremely delighted that we are on the eve of the launch of the service module," said astronaut Michael Baker, director of NASA operations in Russia. "The service module will mark the cornerstone of the start of permanent human habitation aboard the international space station for all humankind.

"It's also the beginning of the real assembly of the international space station with 15 launches scheduled in the next calendar year," he added. "There will be eight shuttle flights, five Progress flights and two Soyuz flights. And of course, the first crew will launch in late October, the first of November, to begin permanent human habitation. And we are ready to proceed."

FRIDAY, JULY 7, 2000
0220 GMT (10:20 p.m. EDT)

Russian space officials believe an anomaly detected during a Proton rocket flight Tuesday night was a sensor problem, clearing the way for next week's launch of the Zvezda service module to the International Space Station aboard the same type of unmanned booster.

The Proton did complete the launch successfully, placing a Russian military satellite into space. However, post-flight examination of data from the launch revealed a chamber pressure problem in the rocket's second stage. Two launch failures last year were caused by engine problems on that stage of the Proton.

After discovering the problem, officials delayed fueling Zvezda Wednesday morning while rocket-maker Khrunichev conducted an analysis.

"Service module fueling was delayed about eight hours while Khrunichev analyzed the data regarding fluctuating chamber pressures in the second stage," a NASA source says. "They proceeded to fuel with what they considered to be a clean vehicle after determining it was a telemetry issue, a sensor, rather than a vehicle issue."

Even so, the source said, "NASA is going to be talking to Khrunichev on Friday to get the story one more time to make absolutely sure they are confident."

At the Baikonur Cosmodrome in Kazakhstan fueling of Zvezda was completed Thursday morning. The module was then transported to the Proton assembly building and mated to the rocket in the past several hours. Rollout to launch pad 23 is scheduled for dawn on Saturday. Liftoff remains scheduled for next Wednesday at 0456 GMT (12:56 a.m. EDT).

WEDNESDAY, JULY 5, 2000
1000 GMT (6 a.m. EDT)

With the successful launch last night by an upgraded Russian Proton rocket, technicians at the Baikonur Cosmodrome in Kazakhstan have begun fueling the Zvezda service module for its journey into orbit next week, NASA spokesman Carlos Fontanot reports from Moscow.

Tuesday's Proton flight, which placed a military data relay satellite into space for the Russian Ministry of Defense, was a crucial milestone in the long-awaited launch of Zvezda. The Proton was making the second of two required qualification flights for the improved RD-0210 engine. The rocket's second stage uses four of the powerplants while the third stage has one.

Space officials said the engine had to complete two successful launches before it could be used by the Proton to loft the precious Zvezda. Following a senior-level review meeting, officials opted to delay fueling Zvezda until after the Proton had completed its second test flight.

So after a flawless launch on June 6 and last night's mission, the engine and Proton are cleared to ferry the next piece of the International Space Station into low-Earth orbit.

Zvezda will serve as a propulsion module to keep the station boosted to a safe altitude above the planet while also acting as the initial crew living quarters.

Once the fueling is completed, the module will be attached to the Proton rocket's third stage sometime tomorrow. The assembled vehicle will then roll to the launch pad no sooner than Friday. Liftoff remains scheduled for next Wednesday, July 12 at around 0456 GMT (12:56 a.m. EDT).

Stay with Spaceflight Now for continuing coverage of the much-anticipated launch of Zvezda, restarting the construction sequence for ISS.