In a spacewalk yesterday, astronauts Steve Swanson and Richard Arnold worked with a robotic arm, dubbed "Canadarm," to get the S6 truss that will hold the arrays maneuvered into place and bolted onto the space station. From inside Discovery today, the astronauts sent instructions to the truss to unfurl the attached solar arrays, which are 230 feet long when spread open and weigh nearly 5,000 pounds on Earth.
The solar arrays are designed to gather energy through 32,800 solar cells and then transfer that power through the truss to the space station's batteries. Unfurled and with data and power cables attached and tested, the arrays are expected to begin delivering energy to the space station sometime today, according to Debbie Nguyen, a spokeswoman for the National Aeronautics and Space Administration.
Nguyen said there was a holdup with the unfurling process when one of the 30 solar panels stuck to another panel. The astronauts, however, waited about 30 minutes while the heat of the sun warmed the arrays and pulled them apart.
With the truss and solar arrays in place, the space station now is 81% complete, according to Nguyen.
She added that the solar arrays will produce enough energy to power 42 2,800-square-feet homes. That will double the amount of power that goes to science experiments onboard the station.
It also means that the space station can now support a crew of six to eight astronauts. Right now, there is a crew of three aboard the station, but that number will be bumped up to six later this year because of the extra energy capacity, said Nguyen.
"This was a vital piece of hardware we installed today," she added. "It was vital for this mission."
The space shuttle Discovery docked with the space station on Tuesday afternoon.
NASA said that a robotic arm on the space shuttle, as well as one on the space station, played critical roles in yesterday's installation of the truss. Mike Curie, a spokesman for NASA, told Computerworld on Thursday that the astronauts simply couldn't have done the work without the use of robotics.
"We rely heavily on the combination of robotics and astronauts to accomplish these tasks," said Curie. "Without Canadarm 2 and the original Canadarm on the shuttle, we wouldn't be able to move these heavy objects. We would never be able to complete the space shuttle without these robotics. They're essential to the construction of the International Space Station."
Last fall, NASA said the future of space exploration will depend on humans and robots working hand in hand as manned and unmanned missions head back to the moon and to Mars and farther expanses of space.