Station commander Bill Shepherd speaks during the first news conference of his mission. Photo: NASA TV/Spaceflight Now

Learning from experience, U.S. and Russian flight planners are slowly zeroing in on more realistic schedules for the international space station's hard-working crew. But the commander says there's still plenty of room for improvement and in the meantime, patience is the watchword.

"We have got to really be patient about commands and directives that come from the ground, things that we tell the ground that we need or need to have done," station skipper William Shepherd told reporters Friday.

"Everybody had really high ambitions for our time, our first time on station, to get a lot done and we're certainly trying to salute that as best we can," he said. "We've been pretty busy cowboys and we've expressed that to the ground and the ground has modified the schedule.

"The schedule is still not perfect, we're having some really long days every once in a while, but it is getting better," Shepherd said. "I think it's a learning curve and everybody's on it right now."

Shepherd, Yuri Gidzenko and Sergei Krikalev, the station's first full-time crew, were launched aboard a Russian Soyuz ferry craft Oct. 31 and docked with the station two days later. Saturday marks their 37th day aboard the international outpost.

Charged with activating critical life support systems and getting the new station up and running, Shepherd and company have been putting in 16-hour days, struggling to overcome a string of technical problems and overly ambitious flight plans radioed up from Moscow and Houston.

Yuri Gidzenko and Sergei Krikalev at work in the Zvezda module on Friday. Photo: NASA TV/Spaceflight Now

At times, Shepherd has virtually pleaded with U.S. flight controllers to intervene in Moscow to reduce the exhausting workload.

"We don't have much free time right now," Krikalev said Friday. "But as Shep said, it's a learning curve, not only for the crew but also for the ground. Speaking about the schedule, it's not because people over book us, they just estimate time to do some tasks wrong. That's a learning experience."

Station flight director John Curry gave a simple example. A device called the Floating Potential Probe, designed to measure the station's electrical environment, was installed during a spacewalk by the shuttle Endeavour's crew Dec. 7. The station crew was asked to activate the system the next day.

"We had Windows 95 on some of the laptops on board - most people can appreciate this - and they were loading in Windows 98 today because the software needed to operate the Floating Potential Probe, we needed Windows 98 to be loaded," Curry said.

"It turned out, for whatever reason with that disk, it took two hours to get that software loaded. Those kind of things, it's hard to account for. But we learn lessons on how to do these things, and the next time they come around we budget better. So two hours is what we're going to budget the next time they're doing loading of software."

The Endeavour docked with the station Dec. 2. Over the past week, the shuttle's five-man crew installed a $600 million solar power array that clears the way for launch of the U.S. laboratory module, Destiny, next month aboard the shuttle Atlantis.

The space station's newly installed solar arrays backdropped by the Earth. Photo: NASA TV/Spaceflight Now

Endeavour docked to a downward-facing port on the station's Unity module. To make way for the orbiter, an unmanned Progress supply ship docked to a nearby port on the Russian-built, NASA-financed Zarya module had to be undocked and placed in a parking orbit.

The Progress M1-4 vehicle linked up with the station on Nov. 18. But its automatic KURS guidance system failed, forcing Gidzenko to carry out a manual, remotely piloted docking using the backup TORU system.

The original flight plan called for the Progress vehicle to deorbited shortly after undocking Dec. 1. But the Russians want to redock the craft, in part to test a software patch designed to correct the KURS guidance system problem.

But the KURS system cannot guide the spacecraft all the way to docking. One of its rendezvous antennas retracted as planned shortly before docking Nov. 18 and from 200 meters on in, Gidzenko will have to remotely pilot the spacecraft.

Assuming NASA managers go along.

Lead station flight controller Jeff Hanley initially said a deliberate manual docking violated NASA's flight rules because the TORU system has no backup. But it now appears the Russians will, in fact, attempt a redocking.

And they'll likely do it on Christmas day.

"That's mostly because of lighting conditions," Curry said. "On Christmas day, we're going to bring the Progress back to the station-keeping distance just to verify the KURS is, in fact, working with the patch that they put on there, that's the key mission objective.

"And then we'll have a second set of criteria to determine if we'll press with the final redocking."

The station crew needs the Progress primarily to increase the station's trash stowage volume. Krikalev said the risks associated with a manual redocking were outweighed by the benefits of having the vehicle in place.