"700 Waivers, Deviations And Exceptions"

When the space shuttle Columbia disintegrated over Texas February 1st, the single program most immediately affected was the International Space Station. So dependent on frequent shuttle flights for replacement parts and personnel, as well as new equipment and waste retrieval, the $30 billion ISS has been living on the edge.

The three-person crew has been reduced to two. That saves on supplies, but doesn't do anything to replace the equipment already onboard when it fails. The shuttles won't fly again until at least late next year. So what if something breaks?

The ISS crew has a way back to Earth, of course. There's an emergency taxi waiting for them just outside the door. But before the shuttles fly, will there come a time when the risks simply pile up beyond acceptable levels?

As the Washington Post reports, NASA last week released an 84-page report on the implementation of recommendations from the Columbia Accident Review Board (CAIB). ]

It says NASA employees are now going over a growing list of more than "700 waivers, deviations and exceptions," hoping they won't find reason to repeat one of the most stinging criticisms of the shuttle program: an "accumulation of risk over time."

With a long, hard glance back in time to last February, they're looking for issues "that carry safety risks of a catastrophic nature," the NASA report said. Depending on what they find, there could be changes to modifications in the space station itself or NASA could simply change the rules.

In essence, NASA engineers and scientists are looking at six different systems, identified less than two months after the Columbia disaster, that could wear out, break down or become depleted. In a striking resemblance to the Russian Mir project in its later days, the ISS crew has already been forced to implement workaround measures to some problems. But there are others where the crew has barely held ground and there are issues that have grown worse.

The More Things Change?

Case in point: ISS managers have until February to decide on a spacewalk that will require both crew members to be outside the station at the same time. Both crew members. As in, no one left inside. They're supposed to make ready for the arrival. They have to consider contingencies like, what happens if the command and control computer malfunctions or even locks up? The entire station is run from that one system. It's recently developed a reputation for periodically displaying the ISS equivalent of the "blue screen of death."

What happens if the power goes out? What about sudden and unexpected changes in the station's attitude? Who'll watch for trouble ahead by monitoring the station's essential systems? What happens if problems develop with the airlock?

A lot of things can go wrong in the span of a six-hour spacewalk.

The Post reports a flight surgeon at Johnson Space Center was aghast when he heard of the plan. The paper quotes him as saying, "Those of us who care for the astronauts don't understand why they're willing to take this kind of risk. What's so important that we have to do this now?"

Space station manager William Gerstenmaier, along with NASA Administrator Sean O'Keefe, acknowledges the two-man spacewalk would increase the overall risk. "We took a look at it from an overall cursory view to see if there were any major show stoppers that would prevent us from [doing the spacewalk], and we didn't find any," Gerstenmaier told the Post earlier.

"We do recognize that there are several failures that could occur that could cause [the] station to go into a loss of attitude," Gerstenmaier said. But he figures that's not an unrecoverable problem.

It's been six months since the ISS team switched to a two-man crew and NASA officials say they're a lot more confident about what they can do without the third crew member.

"I don't think there's any additional risk with a two-man crew versus a three-man crew," Gerstenmaier told the Post. "What we've seen through this actual mission is that our response time with [a two-man] crew is totally satisfactory," he said.

But time is considered one of the station's worst enemies. Things wear out. And the current schedule of Progress launches just aren't enough to keep pace. Essential repairs may become critical repairs before parts can be sent up on the Russian resupply rocket. Two months ago, Congress's General Accounting Office said the situation has caused a number of safety issues, including:

• delays transporting more shielding to protect the station against debris floating in space
• Failure to replace a failed gyroscope -- one of four that keep the station stable
• Failure to analyze the cause of the gyro failure.
• a power-distribution box that failed to meet requirements for vibration endurance
• a robot-arm workstation which, as installed, has wires smaller than specified
• radiator glitches
• problems in the onboard heart defibrillator

If that's not enough, the Post reports there's a growing fire danger. With trash piling up and Progress flights infrequent, some of the fire detection and extinguishing ports are blocked by stowed equipment and debris. The Post also reports concerns that a portion of the water supply may be contaminated with carbon tetrachloride. That's a bad thing.

Given that NASA's own mid-level scientists objected to the idea of this ISS mission in the first place, there now calls for abandoning the space station until the shuttles fly again, almost a year from now.

FMI: www.spaceflight.nasa.gov/station