[sarex] SARJ Takes Charge, Arrays Track Sun

Arthur Rowe azrowe80 at verizon.net
Wed Dec 13 19:13:32 PST 2006

> *SARJ Takes Charge, Arrays Track Sun*
> The International Space Station’s newest set of solar arrays is 
> tracking the sun tonight, following partial retraction of a similar 
> array that’s been the station’s primary power plant for six years. 
> This event sets the stage for two challenging spacewalks by the 
> STS-116 crew to rewire and reroute the station’s power system.
> The Solar Alpha Rotary Joint (SARJ) and the new set of arrays are a 
> part of the P3/ P4 truss segments that were installed onto the station 
> in September during the STS-115 mission. The rotary joint enables the 
> solar arrays to follow the sun and generate the maximum power 
> possible. Activation of the SARJ occurred shortly before 8 p.m. EST, 
> and a few minutes later the Mission Control Center in Houston notified 
> the crew that the arrays were following the sun.
> Throughout the day, the STS-116 crew and flight controllers worked 
> together to solve problems that prevented the P6 truss port solar 
> arrays from folding properly. The retraction activities of the arrays 
> began at 1:28 p.m. More than 40 commands were sent to furl and unfurl 
> the arrays in an attempt to properly align them. When the efforts 
> concluded about 7:50 p.m., 13.5 of 31 bays had been folded, leaving 
> the port arrays in a safe position that allowed the activation of the 
> P4 rotary joint.
> The crew also received word that Thursday’s spacewalk will take place 
> as planned despite the problems retracting the P6 solar array. Mission 
> Specialists Bob Curbeam and Christer Fuglesang, who conducted the 
> mission’s first spacewalk, are scheduled to begin Thursday’s orbital 
> stroll at 3:12 p.m. They will begin efforts to rewire the station, 
> bringing power generated by the P4 arrays on line for use by the 
> station's systems and prepare for more arrays to be added next year.
> In preparation for the spacewalk, Curbeam and Fuglesang will again 
> "campout" in the station’s airlock. The pressure will be lowered in 
> the airlock to the pressure normally found on Earth 10,000 feet above 
> sea level during the overnight campout. The procedure protects against 
> decompression sickness as Curbeam and Fuglesang go to the even lower 
> pressure of spacesuits on Thursday.
> For the latest news and information on the International Space Station 
> and the Expedition 14 crew, please visit the main station page. + Read 
> more <http://www.nasa.gov/station>

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