Two NASA astronauts installed the seventh and final set of mounting hardware for new sets of solar arrays during a successful 6.5-hour spacewalk outside of the International Space Station.

Jessica Meir and Anil Menon on Thursday (Aug. 6), assembled the modification kit for one of the space station's eight power channels, which will allow for the future addition of a new ISS Rolll-Out Solar Array (iROSA). Since 2021, astronauts on prior spacewalks have deployed six of the iROSA assemblies, leaving now just two awaiting delivery to the station later this year.

Like building a giant erector set, Meir and Menon worked to assemble and bolt together the triangular brackets on the 3B power channel, located on the far right, or starboard (S6) segment of the station's backbone truss. Menon was positioned on an articulating portable foot restraint (APFR) atop a worksite interface (WIFEX), providing a stable angle to work from the truss.

Once the modification kit structure was built and secured to the 3B mast canister, the two spacewalkers routed cabling that will carry the electricity from the future iROSA into the 3B power channel and then covered the struts with multi-layer insulation to protect them from micrometeoroid strikes.

The iROSA wings sit forward of the legacy solar arrays, augmenting their electricity generation rather than replacing it. The station's eight original arrays began showing degraded power output as they exceeded their 15-year design life. When used in tandem with the new iROSA wings, the upgraded system will increase the station's electricity supply by 20% to 30%.

The other power channel currently without an iROSA deployed is 2A on the left, or port side, of the station.

"Anil, you can see the moon to the — well, I am not sure what way you're facing, but…," said Meir, taking a short break during the spacewalk to notice NASA's next destination for astronauts under its Artemis program.

"To my right. Yeah, I see it — thanks for the heads-up," said Menon. "I can see a future moon base there."

"I can see it, too!" Meir said.

Meir later turned her attention to Mars with her closing words of the day.

"On this day in 2012, NASA's robotic rover Curiosity successfully landed on the surface of Mars with the goal of understanding if the planet could have fostered life. Curiosity achieved that goal within a year," she said. "One day, humans will visit Curiosity, propelled by the groundbreaking science, technology demonstrations and operations conducted here on the International Space Station for almost 26 years now."

"Today, we made one more step toward expanding the ISS power system, further sustaining our human presence in low Earth orbit, as we prepare to take those next steps," said Meir.

Thursday's spacewalk began at 8:33 a.m. EDT (1233 GMT) when Meir and Menon switched their spacesuits to internal battery power. After collecting their tools and reentering the Quest airlock, the spacewalk, or extravehicular activity (EVA), concluded at 3:00 p.m. EDT (1900 GMT), 6 hours and 27 minutes after it began.

This was the 96th U.S. EVA and 281st spacewalk overall in support of the International Space Station's assembly, maintenance and enhancement. It was the first career spacewalk for Menon and the sixth for Meir, bringing her total time on EVA to 42 hours and 33 minutes.

This was the first spacewalk for the space station's Expedition 75 crew. There are two more U.S. outings scheduled for this month: EVA 97 will work to replace a space-to-ground antenna on Aug. 13, and EVA 98 will connect power channel cables and data relay systems as part of ongoing maintenance, including preparations for the station's future deorbit, as well as replace a navigational aid used for spacecraft docking on Aug. 25.

A spent rocket body hitting the moon made headlines this week, but the reality is that the unplanned collision by a SpaceX upper stage was just the latest in a long history of human-made objects meeting their end by impacting the lunar surface.

Astronomers around the world kept their telescopes trained on the moon early Wednesday morning (Aug. 5), when the rocket stage from a January 2025 U.S. commercial lunar landing mission was calculated to strike the celestial body. Though the fate of the SpaceX Falcon 9 part was unintentional — solar activity and gravitational forces caused the stage to slam into the moon — the impact offered a rare opportunity to try to observe the flash from the impact and the plume of lunar material it sent flying.

By noon (EDT) on Wednesday, there were no confirmed reports of the impact being caught on film, but a telescope in Chile spotted the debris plume, according to the Associated Press.

"This rare occurrence has decades of history, going back to the Apollo era," wrote Jared Isaacman, NASA's administrator, in a post to his social media accounts. "The reality is that meteoroids strike the lunar surface hourly, with impacts comparable to this upper stage occurring roughly every six days."

Inventorying the impacts

The moon is peppered with the scattered metal remains of missions that missed their mark, came down too quickly or were purposefully sent careening into the regolith to learn more about the makeup of Earth's natural satellite.

In fact, the very first mission to successfully fly by the moon was intended to be an impactor. The former Soviet Union's Luna 1 probe was designed to hit the moon but instead zoomed past its target and entered orbit around the sun on Jan. 2, 1959.

Luna 2, launched nine months later, became humanity's first object to reach the lunar surface, purposefully slamming into Sinus Lunicus ("Bay of Lunik"), along the southeastern edge of Mare Imbrium, on Sept. 14, 1959.

The U.S. followed suit, though not as NASA intended, with the Ranger 4 probe impacting the far side of the moon on April 26, 1962. The mission had included an impactor, but both it and its lander failed to operate due to a failure to deploy the spacecraft's solar arrays.

Once humans began arriving on the moon with NASA's Apollo program, scientists found another reason to direct spent rocket and spacecraft stages into a collision course with the surface. Beginning with Apollo 11 in 1969 and concluding with Apollo 16 in 1972, seismometers were placed on the moon to measure natural "moonquakes" and the effects on the moon when the missions' Saturn SIV-B stages and Apollo lunar module descent stages made hard landings.

The data collected helped geologists learn more about the interior makeup of the moon, including that a rocky mantle exists under the outer crust.

After Apollo, planned impacts (and missions) slowed down, if not outright stopped, but the SpaceX collision on Wednesday was not the first in more than 50 years. Between 1993 and today, 11 probes — four from China, three from Japan, two from the U.S. and one each from India and the European Space Agency (ESA) — were intentionally deorbited at the end of the end of their missions around the moon.

Some of these impacts were performed to discard the craft, but others — like Lunar Prospector, LCROSS and Chandrayaan-1 — helped confirm the presence of water by examining the resulting plume.

Unintentional collisions are fewer in number, as are rocket stages, but are not unprecedented. A rocket body that hit the moon's far side in March 2022, leaving behind a small double crater, was later identified as a Long March 3C rocket that launched China's Chang'e 5-T1 mission around the moon in 2014.

Litter versus liability

Without a large human population on the moon, the risk that these planned and unplanned impacts present at current is minimal. But the concern rises as NASA and other world space agencies, as well as commercial interests, begin to increase the pace on establishing their now-planned sustainable facilities for astronauts to live and work on the lunar surface.

"The future lunar base will incorporate reusable spacecraft that not only deliver astronauts and payloads, but also become part of the infrastructure itself," Isaacman said in his post, referring to how reuse can be a way to reduce the number of vehicles needed to be discarded of on the moon.

The Artemis Accords, an internationally agreed-upon set of standards led by NASA and currently signed onto by 70 countries, also includes a provision for its members that spacecraft and their associated rocket components must be disposed of safely.

The next crew, spacecraft and rocket to fly to the International Space Station are on schedule to meet their mid-September launch date, mission managers and the astronauts told reporters on Monday (Aug. 3).

SpaceX's Crew-13 astronauts — commander Jessica Watkins and pilot Luke Delaney of NASA, mission specialist Josh Kutryk with the Canadian Space Agency and mission specialist Sergey Teteryatnikov of Russia's federal space corporation Roscosmos — will become only the second crew to fly aboard the Dragon spacecraft "Grace" when they lift off no earlier than Sept. 12 from Space Launch Complex-40 at Cape Canaveral Space Force Station in Florida.

They will then dock with the space station the following day to begin a seven-month stay on the orbiting outpost, as part of the Expedition 75/76 crew.

"We expect a very busy mission with lots of station maintenance, both internal and external, with a few EVAs [extravehicular activities, or spacewalks] on the docket," said Watkins, who is the only member of Crew-13 to have flown into space before and will become the first active NASA astronaut to fly on Dragon twice. "[We also expect] visiting vehicle capture and stowage operations, lots of science — very interesting science experiments that will be flying with us as well — and plenty of outreach."

Kutryk will be the fourth Canadian to serve on an ISS crew and the second from his country to fly this year, after Jeremy Hansen launched around the moon on the Artemis II crew in April.

"Personally, myself, I grew up on a cattle farm in Canada. It's a long way from being here with this mission in front of us, but the one thing that has resonated at every twist and turn in that journey has been the complexity of these missions and the enormity of the teams that go into pulling missions like this off," said Kutryk. "So, we need to say thank you to everyone."

Cybertrucks, spacesuits and mudflats

"Every time we do a human spaceflight mission, it gives us an opportunity to strengthen our understanding of low Earth orbit. It gives us an opportunity to broaden our international relationships and an opportunity to showcase to the world what we can do in low Earth orbit for human spaceflight," said Joel Montalbano, NASA's deputy associate administrator for human spaceflight.

During the mission, Watkins, Delaney, Kutryk and Teteryatnikov will take part in research to combat heart disease and Parkinson's disease by studying human stem cell-derived tissues. They will also explore crop production that's important for longer-duration spaceflight missions, and help improve scientists' understanding of blood flow abnormalities that are seen on long missions. The crew will also test new diagnostic medical equipment for keeping an eye on their overall health.

First, though, they must get to space.

"Final integration of the Dragon is complete. The capsule was stacked on the trunk just last week and mission preparations are proceeding well for a mid-September launch," said Dana Weigel, NASA's manager for its low Earth orbit program. "Falcon 9 booster maintenance will kick off this month. That same booster was flown on Crew-12. We are not tracking any major issues for this mission campaign."

This Friday (Aug. 7), the crew will don their SpaceX suits — the first "Rev. 3" models with improved donning and doffing capabilities, as well as adjustments to account for spinal growth on orbit — and get their first chance to board "Grace," their ride into orbit and back. This "test drive" will help them gain some muscle memory — some familiarity within the the vehicle mission — and provide them a very big psychological boost, managers said.

"Grace" will also sport new metal "mud flaps" for its Draco abort thrusters, replacing earlier carbon fiber models. In addition, should the crew encounter an emergency before launch, they will be evacuated from the launch pad area for the first time by Tesla Cybertrucks operated by SpaceX, reducing conflicts when SpaceX and NASA want to launch crewed flights at the near or same time.

"There was a lot of certification that had to go into making sure those Cybertrucks would start up with a gloved hand. There were a lot of tests in terms of making sure you could egress the vehicle with a bulky suit on," Richard Jones, deputy program manager of NASA's commercial crew program, said in a response to a question from collectSPACE and Space.com. "All of those things were proven to be already intact, and they're going to configure those Cybertrucks to be ready."

Departures and arrivals

The four members of Crew-13 will be sharing their time on the space station with outgoing and incoming Russian Soyuz crews, who will launch and land with members of Delaney's astronaut candidate class, "The Flies," selected in 2021.

"It's really exciting to see the class fly," said Delaney. "We're going to be meeting Anil [Menon] up there. He's part of our class. Deniz [Burnham] will come up right behind to replace him. Working closely with both of those two throughout astronaut training, it's really just satisfying."

"I'm slightly hoping we get delayed a little bit, so we have some overlaps, so that way we can have three Flies back to back, he said.

For Kutryk, some timing just cannot be controlled.

"It's about midway through — pretty much perfect timing. That's sarcasm," said Kutryk, referring to the upcoming birth of his third child, who is expected to come into the world while he is on the space station.

"It's been done a couple times before," he said, referring to NASA astronaut Mike Fincke and Randy Bresnik, who both had children born while on the ISS. "I think that my family is ready. I have a wonderful, huge support network, from my wife outwards, around us, and we're looking forward to that challenge and to the uniqueness of this experience."