Space station Alpha crew gears up for shuttle visit
BY WILLIAM HARWOOD
Posted: February 1, 2001
Space station flight director Jeff Hanley said today recent data from the floating potential probe, an instrument installed during a shuttle mission in December, shows charge buildups in the range of eight to 10 volts.
Data from the instrument stopped flowing shortly after it was installed, but Hanley said it is once again functioning and engineers are analyzing the results.
"This arcing business is a theoretically predicted phenomenon under certain ideal conditions," Hanley said. "The FPP data we are gathering, we are hopeful will demonstrate that the phenomenon as it is modeled on the ground thus far is modeled too conservatively and in fact, it is not as pronounced an effect. That's our hope.
The station is equipped with two so-called plasma contactor units, or PCUs, that emit a stream of xenon atoms into space to prevent large charges from building up. Data from the floating potential probe shows the PCUs reduce the already low voltage by three to five volts.
"All indications are the PCUs are doing their job," Hanley said. "We've taken data both with the PCUs on and off and we do see a difference."
Station commander William Shepherd, Yuri Gidzenko and Sergei Krikalev are gearing up for arrival of the space shuttle Atlantis late next week and installation of the $1.38 billion Destiny laboratory module.
Atlantis is scheduled to depart on Feb. 16. About one week later, around Feb. 24, Shepherd and company will strap into their Soyuz ferry ship and move it from the Zvezda command module's aft port to a downward-facing port on the Zarya module.
An unmanned Progress supply ship, tentatively scheduled for launch around Feb. 26, will dock at the command module's aft port two days later.
Along with preparing the station for arrival of Atlantis' crew, the Alpha astronauts are continuing work to inventory on-board supplies and equipment.
Hanley said more than 10,000 individual items are on board, the vast majority of which feature barcodes for use with a computer database listing each item's identity and stowage location.
But Hanley said several thousand items - 20 percent or so - were launched before the current inventory system was perfected.
"That includes some individual pieces of equipment and some bags these things were stowed in. So the crew is pulling these things out, they're going through where these things are stowed, they're actually applying bar codes to the bags and items and then logging that into their inventory management database. That takes a good amount of time to do
"We've given them blocks of time over the last two or three weeks to devote to doing nothing but that."
Otherwise, he said, the station is in generally good health. One of the Zvezda module's batteries requires a bit of manual care to stay properly charged, but so far it is carrying its load as required.
Russian engineers are still troubleshooting apparent communications problems with on-board Russian spacesuits. Hanley said engineers suspect the problem involves interference inside the Zvezda module where the suits were inspected and tested.
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