Space Shuttle Not Doing That Badly

Contrary to wire service reports, the shuttle Atlantis's docking with the international space station early Sunday was a straight-forward affair with no problems of any significance and flight controllers were elated with the results.

"The rendezvous went extremely well from our standpoint," lead flight director Phil Engelauf told reporters at a morning briefing. "The crew flew flawlessly, the vehicle performed flawlessly."

As expected, commander Terrence Wilcutt had no trouble carrying out the final stages of the rendezvous despite the failure of an up-pointing star tracker Friday that normally would have been used to get a navigational fix on the station prior to the final rendezvous sequence.

Instead, Wilcutt rolled the shuttle 90 degrees around 10:30 p.m. Saturday, took a fix with Atlantis's other star tracker - one that points to the shuttle's left — and rolled back to the normal orientation. The simple maneuver only had to be done once and there were no problems.

The Associated Press reported the rendezvous was "a complicated job made even tougher by a failed navigation device...Commander Terrence Wilcutt had to rely on a single star tracker for the rendezvous. Normally two star trackers are used, but only one was working aboard Atlantis."

Reuters reported Atlantis was "partially blinded with the loss of a key navigational tool."

In fact, the final stages of any space station rendezvous use just one star tracker: The upward pointing tracker that looks out along the shuttle's minus-z axis, the one that failed aboard Atlantis on Friday.

The only resulting change in Sunday's rendezvous was the addition of the single 90-degree roll to bring the station into the field of view of the left-pointing minus-Y star tracker for a quick navigational fix.

"Wilcutt flew as perfect a rendezvous as can be diagrammed on a drawing board," said one NASA official who asked not to be named. "It's just unfortunate that some don't understand the technical nature of how a rendezvous is actually executed."
Even with the additional roll maneuver, Wilcutt managed to complete the rendezvous using less fuel than anticipated, which may permit NASA managers to extend the flight by one day.

But a final decision to extend the flight from 11 to 12 days will not be made until early next week. Even so, flight controllers now project Atlantis will have enough propellant and electrical power to support the extra day.

"We successfully docked and in the process we managed to make some gains on our propellant margins and have continued to make some small gains on our power production margins, which give us a little bit more confidence in being able to add the 12th day to the mission," Engelauf said.

The only technical issue under discussion Sunday concerns a brief power surge in one of the shuttle's main circuits shortly after the ship reached orbit. The spike did not trip any circuit breakers, but flight controllers want to understand what caused it.

Atlantis' crew, meanwhile, is pressing ahead with the flight plan and gearing up for a spacewalk early Monday to connect electrically the new Russian Zvezda command module to the rest of the station. The astronauts will not actually open hatches and enter the station until Monday evening.

They did, however, open a hatch leading into a pressurized mating adapter - a tunnel connecting the shuttle and the U.S. Unity module - in order to draw an air sample through Unity's hatch before the station's air purifiers were turned on.

Engineers on the ground want to find out how much material "out gases" from station components between shuttle visits.

"Like in your car when it's hot in the summer and you open the door and you smell some chemical type smells that you didn't when it's cooler or the windows are open, that kind of thing," said station flight director Mark Ferring.

"The materials inside the spacecraft 'out gas' some of their chemicals into the air and over time, that accrues to certain levels to the point where it's above the point where our medical people want them to be," he said.

And Sunday night, U.S. station controllers will upload new software into Unity's flight computers that will enable the system to control a huge solar array package scheduled for attachment later this year.

For now, though, flight controllers are focusing on Atlantis' mission and work to outfit and activate the new Zvezda command module before arrival of the station's first full-time crew in November.

"It was really great to see that the station has changed since the last time we were there with the addition of Zvezda," Ferring said. "It really looks different.

"The assembly is starting to pick up speed and it's very exciting for us to see."

By William Harwood
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