1999 International Space Station Status Report #46

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1999
Report # 46 
 9 a.m. CST, Wednesday, November 24, 1999 
 Mission Control Center, Houston, Texas 
 
 The International Space Station celebrated its first year in orbit
Saturday with no problems affecting the overall operation of the complex
in orbit.

Routine battery cycling and preparations to raise the International Space
Stationís altitude have been the focus of the last week as flight
controllers monitor systems aboard Zarya and Unity.

With batteries 1 and 2 still disconnected from the electrical bus,
engineers cycled the remaining batteries with no issues.  The four
batteries currently getting their charge from Zaryaís twin solar arrays
are handling all electrical needs of the station.

Battery 2 was taken off line early last week when it did not discharge
properly.  Plans are in work by Russian controllers to possibly recover
partial use of battery 1, but those efforts are in the early stages of
development.  The ISS actually can operate with no problems on as few as
three batteries.

Also in planning is the full discharge-charge of the four usable batteries
in a procedure called ëbattery restoration.í  This is done about every six
months on each battery system to maintain the unit and its associated
electronics lifetime to provide the maximum electrical capability to
station systems.

A software patch soon will be uplinked to allow for additional data
readings to be available from Zaryaís systems through Unityís early
communications system via the NASA Tracking and Data Relay Satellite
System.  The majority of these additional ëparametersí center around the
battery systems to allow more insight on electrical currents, voltage and
resets.

ISS flight dynamics experts have developed a reboost procedure that will
be carried out next week to slightly raise the stationís overall altitude
in preparation for the arrival of the Zvezda service module early next
year.  Details of the burn plan using Zaryaís control thrusters are still
being finalized, but the result of the burn will minimize, or even
eliminate, the need for an additional orbit adjust burn prior to Zvezdaís
launch.

Here on the ground, mission operations personnel are in the process of
upgrading the Mission Control Center software, which has no impact on
station operations.

The International Space Station continues to operate in excellent shape as
it orbits at an altitude of 236 by 226 statute miles.  Since the launch of
Zarya a year ago Nov. 20, the ISS has completed more than 5,764 orbits.
Space Station viewing opportunities worldwide are available on the
Internet at:  http://spaceflight.nasa.gov/realdata/sightings/