The Progress video camera views the station while trying to align itself under automatic control. Photo: NASA TV/Spaceflight Now

Improving communications between U.S. and Russian flight controllers remains a major challenge for the international space station team as both sides struggle to iron out differences in operational philosophy.

Not to mention coping with a language barrier and the physical distance - 9,000 miles and nine time zones - between the U.S. and Russian flight control centers.

Case in point: A recent, seemingly unilateral decision by Russian controllers to park an unloaded Progress resupply ship in orbit for a possible redocking early next year, a move NASA managers had said would not be considered because of safety issues.

The Progress M1-4 spacecraft docked to the station Nov. 18. Cosmonaut Yuri Gidzenko, using a television camera and a joystick in the Russian Zvezda module, manually guided the supply ship to a linkup after the supply ship's automatic navigation system failed.

The Progress must be undocked from the Zarya module's downward facing port Dec. 1 to make way for arrival of the shuttle Endeavour the next day. Endeavour, scheduled for launch Thursday evening, will dock with a downward-facing port on the U.S. Unity module.

The Russians originally planned to deorbit the Progress immediately after undocking, but they now plan to place it in a parking orbit instead while engineers assess the possibility of redocking it early next year to give the station crew more volume for trash storage.

NASA managers had said repeatedly that a redocking was out of the question because of the problem with the automatic guidance system and the lack of a backup for the manual system used by Gidzenko. They clearly were caught off guard when the Russians unexpectedly told the station crew the new plan was under consideration.

Today, astronaut Robert Cabana, a senior station manager, said the redocking will only occur if an engineering analysis shows it is, in fact, safe to proceed.

Russian engineers believe the vehicle's initial docking problems were caused by a software problem in the automatic guidance system. That problem apparently can be corrected.

That's the technical side of the story. From a management perspective, improving communications between both control centers to make sure everyone is on the same page is paramount to U.S. managers.

"When you consider what we did, the number of flights it took to stow all that equipment up there, put the station together and then throw an international crew on it and work between the two control centers, I think things are going amazingly well," Cabana said.

"The thing that we've learned most is better communications with our Russian colleagues. The team is working much better in the control center. And we knew it was going to take getting the crew up there and working on these issues to resolve a lot of them. It's difficult to plan everything out perfectly.

"I think the realtime ops are going extremely well," he said. "We sill need to improve our planning process a little bit and the communications between our control centers in the day to day planning of the flight."

Station commander William Shepherd agreed, telling a reporter today "things are not perfect, but they're going pretty smooth compared to where we started seven or eight years ago on this program. It's still a challenge, it's probably one of the bigger ones we've got, but I think our progress has been pretty exceptional."

He said engineers and managers on both sides have "different expectations about how it's all going to work."

"The biggest challenge is to try and make that be a reality and meet everybody's desires and wishes as to how it's going to come together," he said. "Quite often, people in Houston or in Moscow want to do things differently and finding some common ground where everybody's going to be at least satisfied has been a real challenge."

An artist's illustration of Endeavour docked to the space station with the new solar arrays unfurled. Photo: NASA

In the meantime, NASA is pressing ahead with a steady stream of station assembly flights and all systems are "go" for Endeavour's launching Thursday night to deliver a $600 million set of solar arrays to the orbital outpost.

In January, NASA plans to launch the U.S. laboratory module, Destiny, followed by a crew rotation/logistics mission in February, additional supplies in April and the joint airlock module in May.

"If you sit back and look at it, these are really exciting and challenging times for each of us," said shuttle program manager Ronald Dittemore. "The complexity of the flights continues to increase as station assembly progresses.

"STS-97 may be the 101st space shuttle mission, but it is still a mission that will be full of space firsts, as will every space station flight," he said. "The crew will attach the heaviest, largest and most complex piece of station hardware launched so far. Once deployed, the wingspan of the solar arrays will be twice the length of the shuttle, making the station the third brightest star and from our point of view, the most beautiful."

Said Cabana: "I think this is an extremely exciting mission and I can't wait to see those solar arrays deploy. If this flight goes as well as our last one did, I think we're going to show we really know what we're doing and we're going to have great success in the years ahead."