The ISS will turn itself to position the European Space Agency's SOLAR instrument for a better view of the sun.
The instrument has been monitoring the sun's output since it was installed on one of the station's laboratory modules in February 2008, a release from ESA's Paris headquarters said Wednesday.
"That is quite an achievement," says Nadia This, operations engineer at the Belgian User Support and Operations Centre that controls SOLAR. "The instrument was designed to work for only 18 months."
SOLAR needs a direct view of the sun to take measurements but the space station's normal orbit obscures the view for two weeks out of every month.
"We want to record a complete rotation of the sun and that takes around 25 days," Nadia said.
SOLAR started recording a full rotation of the sun Nov. 19 and Saturday will spend two hours turning about 7 degrees so observations can continue.
It will hold this angle for 10 days before returning to its original attitude, ESA officials said.