NASA astronauts Josh Casada and Frank Rubio departed the International Space Station on Saturday for a seven-hour flight into space to install and deploy a newly deployed solar array recently delivered from a SpaceX cargo ship.
Casada and Rubio, both on their first spaceflights, began their spacewalk at 7:16 a.m. EDT (1216 GMT) on Saturday. The start of the flight was officially marked when the astronauts put on their space suits.
The astronauts moved from Quest in the space station’s airlock to the left or right side of the lab’s Sunbeam, where the station’s robotic arm positioned two new ISS Roll-Out Solar Array, or iROSA, modules at the start of this week after pulling them from a stump. SpaceX Dragon cargo pod. The Dragon spacecraft delivered solar arrays to the space station on Nov. 27, along with several tons of supplies and experiments.
The new solar panel covers were wrapped around rollers and rolled up like a yoga mat when attached to a mounting bracket on Starboard 4 or S4, the space station’s section of power pylon, which measures more than the length of a field football from end to end.
The astronauts first removed one of the two newly delivered iROSA modules from its mount by loosening the screws and launch rails. Cassada took a position on a stool at the end of the Canadian-made robotic arm and manually held the solar array coils as the arm moved it toward the S4 truss.
The two astronauts placed the iROSA module on a preassembled mounting bracket during an earlier spacewalk. They slotted the iROSA into its hinge, then installed screws to hold it in place. Casada and Rubio mated electrical connectors to connect the new iROSA module to the space station’s electrical system. Next, they installed a Y-cable to direct the power generated by both the newly installed solar panel and the original S4 solar panel to the lab’s power grid.
A stabilizing bracket connects the new arrays to the station’s feed troughs and rotary joints, which keep the solar wings pointed at the sun as the spacecraft circles the Earth at more than 17,000 miles per hour.
The International Space Station has eight power channels, each powered by electricity generated by a solar panel pavilion that extends from the station’s grid backbone. The new solar array, which was deployed on Saturday, will produce electricity for the space station’s 3A feeder rail.
The original solar arrays were launched on four Space Shuttle missions from 2000 to 2009. As expected, the efficiency of the station’s original solar arrays deteriorated over time. NASA is upgrading the space station’s power system with new solar arrays, costing $103 million, which will partially cover six of the station’s original eight solar arrays.
When all six iROSA modules are deployed at the station, the power system will be capable of generating 215 kilowatts of electricity to support at least another decade of science operations. The update will also house new commercial modules that are expected to launch on the space station.
The first pair of new solar arrays deployed on the space station were launched last year and are installed atop the station’s oldest original solar array array in the P6 truss section, located to the far left of the forward site power plant. Two more iROSA modules are scheduled to launch during SpaceX’s resupply mission next year.
The new solar arrays were supplied to NASA by Boeing, Red Wire and a team of contractors.
Once the new iROSA module was mechanically and electrically integrated into the station’s S4 gears, the astronauts released the clamps that held the deployed solar array in launch configuration. This allowed the covers to gradually open using the stress energy from the composite arms that support the solar cover. The timing mechanism design eliminates the need for motors to power the solar generator.
“It’s starting to move,” one of the astronauts said over radio control, causing support personnel in Houston to applaud.
“It’s amazing,” Casada said. “Yeah, it’s pretty cool,” Rubio added.
The carbon fiber support arms have been returned to their natural shape for storage during launch.
It took about 10 minutes for the solar array to fully unfold in its extended configuration, measuring nearly 63 feet long and 20 feet wide (19 by 6 meters). It is about half the length and half the width of the station’s existing solar arrays. Despite their small size, each of the new panels generates roughly the same amount of electricity as each of the station’s existing solar panels.
Once the blanket was deployed, the astronauts adjusted the tension screws to hold the iROSA blanket in place.
Then, the astronauts returned to the space station gears to rig another iROSA module, which will be installed on the left side of the P4 truss section during the spacewalk scheduled for Dec. 19.
With their tasks completed, Casada and Rubio return to the Quest airlock and seal the hatch. They began repressurizing the bladder at 2:21 PM EDT (1921 GMT), completing the spacewalk with a duration of 7 hours and 5 minutes.
Saturday’s spacewalk was the second of Casada and Rubio’s careers, and the 256th spacewalk since 1998 to support the assembly and maintenance of the International Space Station.
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