If a solution to the joint assembly is not found, the system could hinder the future assembly of the station, especially with regards to the addition of the European and Japanese scientific laboratory modules expected to be installed on the next two shuttle missions.

However, NASA officials state that many options are available to them to work around the problem. In fact, according to the Houston Chronicle newspaper, NASA space station program manager Mike Suffredini states, “I really don't think we are in any situation we can't recover from. It's just a matter of time. We have an obligation to try to get our partners to orbit as quickly as we can."

The solar joint assembly, which was installed during the June 2007 mission of space shuttle Atlantis and its STS-117 crew, was manufactured by the Boeing Company.

Earlier, ISS commander Peggy Whitson tested the shavings taken from the defective SARJ to see if they were, indeed, metallic. Whitson placed a magnet under the paper holding the shavings. They were indeed of a ferrous (iron) composition—thus, metallic. Such information allows investigators to delete some possible sources of the problem with the SARJ.

Back on the ground, Boeing engineers are assisting NASA engineers with determining what can be done to solve the problem.

Both SARJs rotate so that the solar panels are always facing the Sun in order to generate electricity from the sunlight coming in from Earth's star. If one SARJ is not working at nominal conditions, there may not be sufficient electricity generated to run the new scientific laboratories scheduled to be installed in upcoming shuttle missions.

As of the moment, NASA has stopped the rotation of the bad SARJ mechanism, which will reduce the power capacity of the station. The SARJs rotate 360 degrees in order to keep the Sun facing the solar panels.

In any case, the spacewalkers—Scott Parazynski and Doug Wheelock—on the third spacewalk, October 30, 2007 during flight day eight, are continuing with their work with installing a solar power tower (P6 truss) to the P5 truss on the space station. They are removing protective covers from the girder of the tower, along with installing bolts to secure the tower to the station and connecting wires to power the 240-foot solar panels that will be unfurled later during the spacewalk.

Later, on Thursday’s fourth spacewalk, NASA astronauts will look into the SARJ problem, both the faulty one on the port side and the correctly working one on the starboard (left) side of the station. In order to inspect the joints, NASA has extended the mission by one day, making it a fifteen-day mission, now scheduled to land at the Kennedy Space Center on November 7, 2007.

The third spacewalk, as with all of the other spacewalks, are televised live on NASA TELEVISION. The fourth spacewalk is scheduled to begin at 4:28 a.m. EDT (Eastern Daylight Time), 8:28 GMT (Greenwich Mean Time), on Thursday, November 1, 2007.

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