posted 12-20-2022 07:10 PM               

ISS Expedition 68: U.S. Spacewalk 83

NASA astronauts aboard the International Space Station (ISS) will conduct a spacewalk on Wednesday (Dec. 21) to install a rollout solar array to increase electrical power in support of operations and scientific research.

Expedition 68 crewmates Frank Rubio and Josh Cassada are scheduled to exit the Quest airlock at 7:45 a.m. EST (1245 GMT) to install an ISS Roll-Out Solar Array (iROSA) to augment power generation for the 4A power channel on the station's port truss structure.

This will be the fourth iROSA installed on the station out of a planned total of six. Overall, the iROSAs will increase power generation capability by up to 30 percent, increasing the station's total available power from 160 kilowatts to up to 215 kilowatts.

The iROSA being installed on Wednesday arrived at the space station on Nov. 27, following its launch the day earlier aboard the SpaceX's 26th Dragon resupply mission.

Rubio will serve as extravehicular crew member 1 (EV 1) and will wear a suit with red stripes. Cassada will serve as EV 2 and will wear an unmarked suit. The spacewalk will be the third in both Cassada and Rubio's careers.

posted 12-21-2022 08:26 AM               

Spacewalk Postponed Due to Debris Avoidance

While flight control teams were preparing for today's (Dec. 21) spacewalk, updated tracking data on a fragment of from a Russian Fregat-SB upper stage showed a close approach to International Space Station. Based on this new data, flight control teams directed the crew to stop spacewalk preparations as the ground team stepped into procedures to perform a Pre-Determined Debris Avoidance Maneuver (PDAM).

The maneuver used the Progress MS-20 thrusters to provide the complex an extra measure of distance away from the predicted track of the debris. Thruster firing was targeted to occur at 8:42 a.m. EST (1342 GMT). The crew was not in any immediate danger.

Without the maneuver, it was predicted that the fragment could pass within less than a quarter mile from the station.

NASA managers will assess the next possible opportunity to perform the day's planned spacewalk to install a new set of roll-out solar arrays to augment the station's power capabilities.

posted 12-21-2022 12:19 PM               

Spacewalk Rescheduled for Thursday

Frank Rubio and Josh Cassada are now scheduled to begin a spacewalk at 8:30 a.m. EST (1330 GMT) on Thursday (Dec. 22) to augment the International Space Station’s power generation system.

The spacewalk was postponed on Wednesday after it became necessary to fire the Progress MS-20 cargo craft's engines to maneuver the station to avoid an approaching piece of Russian rocket debris.

posted 12-22-2022 02:30 PM               

Spacewalkers install, unfurl 4th roll-out solar array

Frank Rubio and Josh Cassada began the spacewalk at 8:19 a.m. EST (1319 GMT), exiting the U.S. Quest airlock and quickly getting to work on their first assigned tasks. As Cassada set up a foot restraint at the end of the station's Canadarm2 robotic arm, Rubio configured the cables that they would later connect to tie the new array into the station's 4A power channel.

The two astronauts then worked together to free the iROSA from the platform on which it was launched and temporarily stowed on the station. Like the array that was installed on Dec. 3, the 4A iROSA was delivered to orbit by SpaceX's CRS-26 Dragon cargo spacecraft, which arrived at the ISS on Nov. 27.

After Rubio freed the last bolt holding the array in place, Cassada, now positioned at the end of the robotic arm, took hold of the assembly to carry it to its installation site. At the controls of the Canadarm2 was NASA astronaut Nicole Mann, with Koichi Wakata of the Japan Aerospace Exploration Agency (JAXA) coordinating her actions with Cassada outside.

Rubio transitioned along the truss to meet Cassada the P4 site. The two spacewalkers then unfolded the iROSA from its launch configuration and then secured the array atop a mounting bracket installed on an earlier EVA. Using a power tool specifically designed for astronauts to use on spacewalks, Rubio tightened the four bolts on the right and left sides of the iROSA to hold the assembly open.

After waiting for the space station to be in "eclipse," or when it was in the shadow of Earth, such that the existing solar array wings were not producing electricity, Rubio and Cassada then integrated the iROSA into the 4A power channel by attaching cables connecting the new array to the station.

At that point, all that was left to do was let the iROSA unfurl. With the release of two bolts, the potential energy stored by the rolled-up carbon composite booms caused the array to unroll on its own to its full 63-foot (19 meter) length with no motor needed.

The whole process took about 10 minutes. Cassada tightened two bolts to stiffen the array and its installation was complete.

Cassada and Rubio completed the spacewalk by cleaning up and taking inventory of their tools before reentering the airlock at 3:27 p.m. EST (2027 GMT), seven hours and eight minutes after they began the EVA.

Thursday's spacewalk was the third for both Rubio and Cassada. They now have logged 21 hours and 24 minutes working the vacuum of space.

The EVA was the 12th for the year, the fourth for Expedition 68 and 257th since 1998 in support of assembly and maintenance of the ISS.