Image: Crew and spacesuits
NASA
Station commander Bill McArthur and Russian cosmonaut Valery Tokarev stand behind NASA and Russian suits for spacewalks. For a time, equipment concerns left the station in a "no-go" condition for spacewalks, but NASA has come up with a contingency plan.
By NBC News space analyst
Special to MSNBC
updated 3/24/2006 2:44:29 PM ET 2006-03-24T19:44:29
Analysis

Two veteran spacemen are completing their six-month expedition aboard the international space station, and to report on their achievements, NASA conducted a news conference this week with top program officials and scientists.

NASA astronaut Bill McArthur and Russian cosmonaut Valery Tokarev have performed spacewalks, space redockings, experiments and observations substantially above the planned program, and a suite of hardware repairs that had hitherto not been considered feasible.

But from most of the post-conference news coverage, you’d think they had lost their spacesuits and broken the station’s driveway.

The headlines sounded pretty scary: “Spacewalks halted” ... “Spacewalks temporarily suspended” ... “Spacewalks put on hold.” But the truth is that no extravehicular activity has been delayed, by as much as a minute. The next outing on the schedule isn't until July. And even if an earlier spacewalk suddenly becomes necessary, the preparations would proceed at the normal pace.

The “problems” reported this week were the result both of normal space housekeeping and of heightened safety awareness by the space workforce — and there should be no complaints about that.

Here are the realities behind the scary headlines:

NASA officials have developed a contingency plan to address the safety concerns if they had to schedule an emergency spacewalk: If the handrails in space are found to be weaker than expected, spacewalkers would clip their safety harnesses to the stanchions at either end of a handrail, rather than to the handrail itself.

The overlooked story
Most of NASA’s press conference was devoted to details of what officials called the “very successful and rewarding” six months in orbit experienced by McArthur, 55, and Tokarev, 53, on what is obviously their last voyage in space. The crew was “a pleasure to work with,” chief flight director Sally Davis reported. “We got done all that we planned, and even more,” she said.

NASA’s mission manager for Expedition 12, Pete Hasbrook, said schedulers had planned to get seven to nine hours per week of science operations from the crew, squeezed into their heavy load of station maintenance and repair, plus two hours of daily exercise. “We achieved 13 hours a week” for scientific work, he announced.

That was mainly crew time spent to set up, adjust, observe or replace experiments, along with repairs as needed. Much of the science gear runs in automated mode — or is actually remote-controlled by ground scientists using the station’s revolutionary communications links. Out of a group of more than 100 principal investigators, three or four different scientists on Earth are usually simultaneously at work, on different experiments, day and night .

Two of the most important experiments dealt with protein crystal growth and with further investigation of human physiological adaptation to space conditions. Deputy ISS program scientist Julie Robinson gave preliminary results of both:

Keeping busy in orbit
Meanwhile, the crew was given a running list of one- to two-hour tasks to choose from during any spare time that opened up — sort of an orbital "job jar."

"Bill did 87 hours of work off of this list," Davis said. "That’s an additional two full weeks of work."

McArthur dove into all tasks requested of him. Davis recalled that her favorite quotation from his radio communications was about work: “The difference between a workday and a non-workday,” he explained, “is that I get to pick what work I do.”

One special Saturday activity McArthur concentrated on was the study of bubble formation and bubble control — which is a major problem in zero-gravity, because bubbles do not float to the top of the fluids in which they are suspended. During previous space biology experiments, Robinson noted, “bubbles can keep nutrients from spreading, so the cell cultures die” — an unwanted effect. McArthur tumbled himself as a “human centrifuge” to develop better ways to manually filter bubbles from fluids.

This was far from merely a scientific concern. Space station program official Kirk Shireman was asked what had changed to make the formerly troublesome Russian-built oxygen generator run so smoothly in recent months.

"The problems seemed to be related to clogging from bubbles in the water" to be broken down into hydrogen and oxygen, he explained, “and the bubbles are removed manually — so crewmen get better with experience.” In addition, he pointed out that the current unit was the first one from a new manufacturer, so it may have had some design improvements.

Repair crew at work
Continuing the tradition of space repair of equipment originally thought not to be fixable in flight, McArthur installed several spare parts on an air-quality analyzer, constructed a fix-it device for some misaligned connection pins by following instructions from ground controllers — and finally restored the equipment to full operation.

Another achievement came during a spacewalk last November , when McArthur and Tokarev wore NASA spacesuits that had been repaired in orbit. That outing marked the first-ever operation using that hardware without having an extra crewman to assist the two spacewalkers. (The two-person operation is far more common with Russian spacesuits, which are built for more autonomy.)

Aside from the crew activities, the station hardware also acquired new capabilities, Hasbrook reported. Among the most important improvements is the ability now for ground controllers to operate the Canadian robot arm attached to the station, without the need for onboard crew attention. Whenever the arm must be moved without bothering the crew, and especially during intense activity times such as crew handover, the new control mode will save a great deal of time and effort in space.

Correction: An earlier version of this story inaccurately attributed the details of the PromISS and FOOT experiments to flight director Sally Davis; it was deputy ISS program scientist Julie Robinson who provided them.

NBC News space analyst James Oberg spent 22 years at NASA's Johnson Space Center as a Mission Control operator and an orbital designer.

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