Flight controllers in Moscow and Houston have completed the formal checkout of the various systems on the Zarya module and reported it is ready for the arrival of Space Shuttle Endeavour and the next element of the International Space Station - the Unity connecting node.
Completing its first week on
orbit, Zarya was put through the final major systems checkout Friday
as engineers spent the day conducting the orbiter docking test, which
involved verifying a series of specific actions that will take place
prior to Endeavour's rendezvous with Zarya a week from tomorrow. Considered
a "dry run" of commands that will be uplinked during the final
hours of the rendezvous, this docking test included:
This test essentially completed the checkout of systems prior to the shuttle's launch next Thursday.
Additionally, controllers verified an update to the ground software of the air monitoring sensor. The humidity level inside the module was measured over the course of three successive orbits and was reported by the Russian flight director to be within normal parameters by the final check.
Meanwhile, International Space Station program managers are discussing with Russian officials the possibility of flying replacement hardware to Zarya aboard Endeavour next week because of a potential glitch with the energy storage and discharging capability of one of six batteries housed in the Zarya module. The batteries store electricity for operation of the module's systems while the Zarya orbits the Earth in darkness. Battery # 1 is apparently not discharging stored energy properly through automatic methods.
Although the battery is functional and can be operated manually through ground commands, a replacement charging device and a replacement battery controller may be stowed aboard Endeavour for potential replacement by Russian cosmonaut Sergei Krikalev during STS-88 while crew members work inside Zarya. Krikalev has replaced similar hardware on the Mir Space Station in the past.
Thursday, attention was focused on conducting a more detailed test of the Telerobotically Operated, or TORU, manual docking system to verify the signal strength from two small antennae on the exterior of Zarya. Russian flight controllers said data from the tests indicated that the signal strength was indicative of a deployed antenna, although it cannot be confirmed at this time that the antennae are, in fact, fully deployed. No additional tests are planned prior to the STS-88 shuttle mission, but photo documentation of the antennae is likely to be requested of the shuttle crew during the approach and berthing operations, and possibly during one of the three spacewalks planned for the flight, to visually verify the antennae position.
The TORU system is a manually operated docking system that serves as a backup for the Kurs automated docking system, which is the primary docking system to be used for the arrival of the Service Module in summer 1999.
Over the weekend, activities will focus on conducting systems health checks with all formal checkouts having been completed. No other major activities are planned before Endeavour's launch on the first International Space Station assembly mission.
During times when Zarya is not actively performing systems checks or other operations, it is put into a slow spin to conserve fuel and maintain moderate temperatures on the spacecraft.
Zarya is circling Earth once every 92 minutes in an orbit of 250 by 240 statute miles.
The next ISS status report is planned for Monday, November 30, or as developments warrant.
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