Whitson, Tani Repair Problem To Power Generation System
Let there be light... onboard the International Space Station,
that is. Early Wednesday afternoon, Expedition 16 Commander Peggy
Whitson and Flight Engineer Dan Tani finished a seven hour, 10
minute spacewalk outside the ISS, to make repairs on the starboard
side of the truss structure.
NASA reports the spacewalkers successfully removed and replaced
a Bearing Motor Roll Ring Module (BMRRM) that experienced
electrical failure December 8. The BMRRM, or "broom," drives the
solar arrays as they tilt towards the sun, maximizing power
While the panels continued to produce energy, the faulty motor
prevented the panels on the station's right side from tracking the
sun, curbing the station's power-generation capabilities.
Mission Control reported good electrical continuity to the new
BMRRM. While spacewalkers were still outside, flight controllers
completed a planned three-degree rotation and then did a 360-degree
rotation of those solar wings. NASA engineers pronounced the
repairs a success, stating the station's right-side solar power
module is now generating enough power to support the planned
deliveries of the Japanese "Kibo" science module to the station in
March and April.
"Yee haw," said Whitson, when Mission Control told her the
repair was successful. "Thanks a lot."
"Great. Fantastic," echoed Tani, reports The Houston
The excursion was somewhat riskier than other spacewalks, as the
astronauts had to work in close proximity to the high-voltage solar
panels. The spacewalkers could only work while the station was in
darkness... as when sunlight hits the panels, dangerously high
levels of electricity spike through the cables they had to
The motor is part of the Beta Gimbal
Assembly, which experienced electrical failures December 8.
Including pauses for the daylight parts of orbit, the removal and
replacement of the BMRRM took about three hours.
The second major task of the spacewalk was inspection of the
starboard Solar Alpha Rotary Joint (SARJ), which causes the
starboard solar wings to rotate in a paddlewheel-like motion to
keep the arrays pointed toward the sun. Previous inspections
revealed contamination and debris inside that joint. Eight SARJ
covers were removed for Wednesday's inspection.
Station Flight Engineer Yuri Malenchenko helped the crew with
suiting up and provided other support. Astronaut Tom Marshburn was
the ground intravehicular officer. He was in the station flight
control room in Houston's Mission Control Center, acting as
Once tasks their tasks were completed and after cleanup the
spacewalkers re-entered the Quest airlock and closed its hatch. The
beginning of repressurization at 1206 EST marked the official end
of the spacewalk.
(Photo courtesy of NASA TV)