In this image from NASA TV, the international space station begins the process of opening new solar wings while orbiting Earth on Friday. (NASA TV/Associated Press)

NASA and astronauts aboard the International Space Station extended the station's new set of solar wings successfully on Friday, a process that will double the amount of electricity available for science experiments on the orbiting outpost.

To NASA's relief, both wings went out smoothly, one at a time. Nothing hung up, and none of the panels stuck together as they had in the past.

"It's just really amazing," said Mike Fincke, the space station's skipper. He said there was "a shout of triumph" aboard the linked station-shuttle complex once the two wings were fully extended.

The structure holding the two starboard solar arrays, which stretched to 73 metres after they were fully extended Friday, was delivered to the space shuttle Discovery on Tuesday and installed on Thursday.

NASA had concerns about the unfurling of the arrays, a process that has caused problems in the past. During Discovery's October 2007 mission, one of the port-side array's solar wings tore when the wires that guide the solar panels got snagged as it was being unfurled. That problem came as a result of earlier difficulties folding the array when it was moved from one part of the station to its current location on the port side of the station.

As a precaution, NASA said Friday morning Mission Control had deployed the arrays a short distance to confirm they were working properly.

NASA began extending the first array at 11:06 a.m. ET. Astronaut John Phillips allowed the wing to open halfway, then paused for almost an hour to judge how the process was progressing and so the panels could soak up sunlight and be less likely to stick.

The second wing opened just as easily. A slight crinkle was spotted near the bottom, but flattened when the wing was stretched out.

When fully functioning, the two solar wings will double the electricity available for space science operations, from 15 to 30 kilowatts. Altogether, the station's full complement of arrays will generate as much as 120 kilowatts of usable electricity, enough to power 42 2800-square-foot homes.

The space shuttle Discovery arrived at the station on Tuesday and will be departing next week after an eight-day stay.

The astronauts are also scheduled to install a replacement part for the station's new water recycling system. That part failed after the space shuttle Endeavour departed in December.

Discovery needs to be gone from the space station before a Russian Soyuz rocket blasts off March 26 with a fresh station crew.

With files from the Associated Press