US Spacewalk 99: Astronauts Install Camera, Docking Port Retroflector, On The ISS

NASA astronaut Jessica Meir and ESA (European Space Agency) astronaut Sophie Adenot completed U.S. Spacewalk 99 Tuesday (Sept. 1), a historic sixth all-female spacewalk in human spaceflight history. Beginning at 1240 UTC, the 6-hour, 49-minute extravehicular activity (EVA) focused on station navigation, scientific maintenance, and infrastructure upgrades.

The primary task was installing a new retroreflector on the Harmony module Node 2’s forward port to support spacecraft docking and rendezvous operations. The older reflector that they replaced had become coated in thruster residue from earlier spacecraft arrivals and departures.

The duo also replaced a high-definition Camera Port 3 (CP3) camera on the station’s truss. "And it's off!" reported Meir after freeing the spent camera assembly that was swapped out for spare. Her words were met by applause in Mission Control at NASA's Johnson Space Center in Houston.

"That worked, great!" she said.

Adenot (EV-1) continued an ongoing scientific study by swabbing areas on the exterior of the airlock and her gloves for possible microorganisms. Meir, meanwhile, rode one end of the Canadarm2 robotic arm to a site near the Alpha Magnetic Spectrometer (AMS), torquing 46 bolts in preparation for future maintenance of the particle physics detector.

Meir (EV-2) also relocated power and thermal jumper cables and an articulating portable foot restraint for use on a later spacewalk.

Mission Control deferred installing the remaining guide studs for the spectrometer’s replacement radiator so engineers can develop a plan to finish the work during a future spacewalk. As the crew fell behind the timeline, the mission control team also shifted completion of the remaining jumper cables and other noncritical tasks to a later date.

During the excursion, Adenot experienced a temporary left-arm mobility issue caused by a glove heater harness. Meir took a look at Adenot’s suit and determined the glove heater harness was likely getting caught and causing limited movement in the left shoulder joint. Unzipping the joint seemed to resolve the issue ahead of the crew entering the airlock.

There were some other tasks planned, time permitting, but toward the end of the EVA, Adenot reported losing mobility in her left shoulder joint. Erring on the side of caution, Mission Control called for Adenot to wait where she was until Meir could follow her back to the airlock.

Once there, Meir was able to unzip a portion of Adenot's extravehicular mobility unit's (EMU's) upper arm assembly to inspect what was happening. In doing so, she freed the kink that had limited Adenot's motion.

"I think it was where the cable got caught in between the shoulder MLI [multi-layer insulation] and the rotation [joint]. I don't think it was held up by anything but some friction," said Meir.

The two Expedition 75 crewmates then proceeded back into the airlock to complete the EVA at 2029 UTC.

Meir completed her seventh spacewalk, moving into third place among NASA women astronauts for total EVAs, trailing only Peggy Whitson (10) and Suni Williams (9). Adenot completed her third spacewalk, becoming the first French woman to perform an EVA. Tuesday's mission was also the 284th spacewalk in support of space station assembly, maintenance, and upgrades.