Astronauts install a new solar array outside the International Space Station – Spaceflight Now

NASA astronauts Josh Cassada and Frank Rubio headed off the International Space Station on Saturday for a seven-hour spacewalk to install and deploy a new solar array recently delivered by a SpaceX cargo ship.

Cassada and Rubio, both on their first flights into space, began the spacewalk at 7:16 am EST (1216 GMT) on Saturday. The start of the excursion was officially marked when the astronauts changed their spacesuits to batteries.

The astronauts moved from the space station’s Quest airlock to the starboard, or right, side of the laboratory’s Solar Power Armor, where the station’s robotic arm positioned two new ISS Roll-Out Solar Array units, or iROSA, earlier this week after removing them from the trunk of a SpaceX Dragon cargo capsule. The Dragon spacecraft delivered the solar arrays to the space station on November 27, along with several tons of supplies and experiments.

The new blankets of solar panels were wrapped around spools and unrolled like a yoga mat once installed on a mounting bracket on the starboard section 4, or S4, of the space station’s power truss, which measures more than than the length of a football field from the end. to end.

The astronauts initially worked to remove one of the two newly delivered iROSA units from its carrier by releasing bolts and launch restraints. Cassada positioned himself on a footrest at the end of the Canadian-built robotic arm and held the spools of the solar panels in his hand as the arm moved him toward the S4 frame.

The two spacewalkers placed the iROSA unit on a mounting bracket previously placed during a previous spacewalk. They unfolded the iROSA unit on its hinge, then installed bolts to secure it in place. Cassada and Rubio attached electrical connectors to connect the new iROSA unit to the space station’s electrical system. They then attached a Y-cable to route the power generated by both the new deployable solar panel and the original S4 solar panel to the lab’s electrical grid.

The mounting bracket connects new arrangements to the station’s power channels and rotary joints, which keep the solar wings pointed toward the sun as the spacecraft circles Earth at more than 17,000 mph.

The International Space Station has eight power channels, each powered by electrical power generated by a wing of solar panels that extends from the station’s spine. The new solar array deployed on Saturday will produce electricity for the space station’s 3A power channel.

The original solar arrays were launched on four Space Shuttle missions between 2000 and 2009. Unsurprisingly, the efficiency of the station’s original solar arrays has degraded over time. NASA is upgrading the space station’s power system with the new $103 million deployable solar arrays, which will partially cover six of the station’s original eight arrays.

When all six iROSA units are installed 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 upgrade will also accommodate new commercial modules planned for launch to the space station.

The first pair of new deployable solar arrays were launched on the space station last year and were installed on top of the station’s oldest set of original solar arrays in the P6 truss section, located at the far left of the post’s power truss. advanced. Two more iROSA units are scheduled to launch on a SpaceX resupply mission next year.

The new solar panels were supplied to NASA by Boeing, Redwire and a team of subcontractors.

Once the new iROSA unit was mechanically and electrically integrated into the station’s S4 truss, the astronauts released the clamps that held the coiled solar array in its launch configuration. That allowed the blankets to gradually unroll using tension energy in the composite arms that support the solar blanket. The deployment mechanism design eliminates the need for motors to drive the solar array.

“It’s starting to move,” one of the astronauts radioed to mission control, drawing applause from the support team in Houston.

“That’s incredible,” Cassada said. “Yeah, it’s great,” Rubio chimed in.

The carbon fiber support arms were rolled up against their natural shape for storage during launch.

The solar array took about 10 minutes to unfold to its fully extended configuration, stretching out about 63 feet long and 20 feet wide (19 by 6 meters). That’s about half the length and half the width of the station’s current solar arrays. Despite their smaller size, each of the new arrays generates roughly the same amount of electricity as each of the station’s existing solar panels.

Once the blanket was deployed, the astronauts tightened the tension bolts to secure the iROSA blanket in place.

The astronauts then returned aboard the space station truss to prepare another iROSA unit, which will be installed in the left-side section of the P4 truss for a spacewalk tentatively scheduled for December 19.

With their tasks completed, Cassada and Rubio returned to the Quest airlock and closed the hatch. They began repressurizing the airlolk compartment at 2:21 pm EST (1921 GMT), completing the 7-hour, 5-minute spacewalk.

Saturday’s spacewalk was the second in the careers of Cassada and Rubio, and the 256th spacewalk since 1998 in support of the assembly and maintenance of the International Space Station.

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Follow Stephen Clark on Twitter: @StephenClark1.