2 p.m. CST, Thursday, November 18, 1999

Mission Control Center, Houston, Texas

Flight controllers in Moscow and Houston began the second round of deep-cycling of
the batteries inside the Zarya module last weekend, but stopped the procedure when
the first battery did not discharge properly. The deep cycling of the batteries is done
about every six months to maintain the units efficiency and lifetime to provide the
maximum electrical capability to station systems.

Battery number two completed a discharge-charge cycle, but failed to discharge on
the second cycle. At that point, controllers removed it from the electrical bus. The four
usable batteries are easily handling all electrical needs of the station and no power
problems are foreseen since the complex can operate on as few as three batteries.

While this in no way hampers station operations, some heaters on the Unity module
were powered off to minimize power consumption. The station currently is in near full
sunlight as it moves around the Earth, so no power problems or temperature issues
are foreseen. Troubleshooting on the battery two system – comprised of the battery
and its associated electronics – is underway and no conclusion has been made as to
what caused it not to discharge properly.

Battery three was cycled yesterday with no issues. Evaluation and analysis will be
conducted during the next day or so before a decision will be made regarding
resumption of cycling of batteries four, five and six. During the present battery cycling,
Unity’s early communications system is being used to supplement Russian ground
station commanding to Zarya’s batteries and other systems.

Meanwhile, ISS managers are reviewing details of a reboost plan for the ISS. The
reboost, scheduled for December 1, will raise the complex’s orbit to eventually place it
at the proper altitude for rendezvous with the Zvezda service module scheduled to
launch to the ISS early next year.

All other station systems are in excellent shape as it orbits at an altitude of 239 by
225 statute miles. Since the launch of Zarya last November, the ISS has completed
more than 5,686 orbits. Space Station viewing opportunities worldwide are available on
the Internet at: http://spaceflight.nasa.gov/realdata/sightings/

At the Kennedy Space Center, Florida, another piece of the station’s ‘backbone’
arrived for processing. One of the left-side 40-foot-long truss segments was shipped via
Super Guppy from Tulsa, Oklahoma, to Florida, arriving today. That makes three truss
segments on dock at KSC joining the Z1 truss element, first set of solar arrays, the
Destiny laboratory, two multi purpose logistics modules (Leonardo and Rafaello), and
the Canadian supplied remote manipulator system (station robot arm).

Due to the observance of Thanksgiving on Thursday, November 25, the next
International Space Station status report will be issued on Wednesday, November 24.
For further information, please contact the NASA Public Affairs Office at the Johnson
Space Center, Houston, Texas, 281-483-5111.

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