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Published:February 12th, 2007 13:39 EST
NASA Circuit Breaker Trip Early Sunday Caused a power outage on the International Space Station

NASA Circuit Breaker Trip Early Sunday Caused a power outage on the International Space Station

By SOP newswire

HOUSTON - An unexpected circuit breaker trip early Sunday caused a
power outage on the International Space Station. All systems were
back up by Monday morning with no impact to operations on board. The
safety of the Expedition 14 crew and the complex was never an issue.

The first indications of a problem came with the loss of
communications between the station and mission control just after
12:00 a.m. CST Sunday when an electrical switching unit experienced a
brief malfunction that appropriately caused a breaker to trip,
protecting the electrical system of the station much like a circuit
breaker protects electrical systems and equipment in a home.

Expedition 14 Commander Mike Lopez-Alegria and Flight Engineers
Mikhail Tyurin and Suni Williams - awake since mid-evening Saturday -
took immediate action and followed procedures on board to recover the
communications link with mission control, Houston, at about 1:35 a.m.

During the remainder of Sunday and through early Monday, restoration
of systems continued. The systems affected included:

One of two redundant communications systems

One of four gyroscopes used to maintain the station's position, or

Several scientific facilities, including the freezer containing
experiment samples

The Ku Band high data rate and television system

Several smoke detectors and various heaters that maintain a thermal
balance of external components, including the robotic arm and its
mobile base

None of these systems was permanently affected, and the equipment's
temporary shut down did not impact research work or upcoming planned

In addition to the recovery from the power outage, the crew also began
early preparations for the next spacewalk by Tyurin and
Lopez-Alegria. During that spacewalk scheduled for Feb. 22, the two
will free a stuck antenna on the ISS Progress 23 supply craft and
survey navigation systems for the European Automated Transfer
Vehicle's docking capability to the Zvezda Service Module. They will
try to secure or remove the antenna to preclude any interference
during undocking in April. The spacewalk will be the 10th for
Lopez-Alegria, which will be a U.S. astronaut record. The two will
wear Russian Orlan suits for the excursion out of the Pirs docking

Allard Beutel
Headquarters, Washington

Kyle Herring
Johnson Space Center, Houston