Expedition 67 in final stretch as European Robotic Arm commissioning continues

by William Graham

July saw Expedition 67 aboard the International Space Station reach two-thirds distance, with two months remaining until its longest-serving crewmembers return home and the rest of the crew transitions to the next increment. Over the course of the month, the crew has been continuing scientific research and housekeeping tasks around the station, while also receiving supplies from a Cargo Dragon freighter and performing a spacewalk on the Russian segment of the outpost.

Long-duration missions to the space station are designated Expeditions, with each expedition lasting approximately six months. Expedition changeovers usually coincide with Russian crew rotations, with each expedition ending when the outgoing Soyuz spacecraft departs. Crewmembers arriving on other spacecraft will typically join an expedition partway through, transitioning to the next expedition crew until relieved by their replacements.

Currently, the ISS is crewed by Expedition 67, which began in March when Soyuz MS-19 returned to Earth and will continue until Soyuz MS-21 leaves at the end of September. Expedition 67 is commanded by Russia’s Oleg Artemyev, who took over from Thomas Marshburn in May when Marshburn returned to Earth with the SpaceX Crew-3 mission. Artemyev is joined by fellow Russians Denis Matveev and Sergey Korsakov, US astronauts Kjell Lindgren, Bob Hines, and Jessica Watkins, and European Space Agency (ESA) astronaut Samantha Cristoforetti of Italy.

Four members of Expedition 67 in their living quarters — clockwise from top: Hines, Cristoforetti, Watkins, Lindgren (Credit: NASA)

The month began with four visiting spacecraft docked at the station. On the US Orbital Segment (USOS), Crew Dragon Freedom was at the zenith, or Earth-opposed, port of the Harmony module, connected via the Pressurized Mating Adaptor 2 (PMA-2) and International Docking Adaptor Zenith (IDA-Z) docking adaptors. This was the spacecraft that brought the US and ESA astronauts to the station in April and is remaining at the station during their stay to serve as a lifeboat and their ride home at the end of their mission.

On the Russian Orbital Segment (ROS), three spacecraft were docked. Soyuz MS-21 is at the nadir, or Earth-facing, port of the Prichal module, having arrived with the Russian crew in March. The Progress MS-19 and MS-20 cargo spacecraft were docked to the zenith port of the Poisk module and the aft port of the Zvezda module, respectively.

The crew aboard the International Space Station are always busy, carrying out a wide range of tasks to keep the outpost operational, performing research in its various laboratories, and maintaining their home in space. As the only seven humans aboard the station, the crew is responsible for anything and everything that cannot be automated or carried out remotely.

Early in the month, the crew demonstrated for the first time the use of the Nanoracks Bishop Airlock to dispose of trash. After astronauts loaded a bag containing about 78 kilograms of common trash into the airlock, the CanadArm2 robotic arm was used to unberth the airlock and position it for the operation – this step being necessary as the airlock empties into space through the same hatch that the crew used to load it while berthed.

The Bishop Airlock on the end of CanadArm2 during the trash dump. (Credit: NASA)

The bag was jettisoned successfully at 00:05 on 3 July, after which the airlock was re-berthed with the port-side Common Berthing Mechanism (CBM) of the Tranquility module. The crew subsequently oversaw the repressurization of the airlock and the vestibule between it and Tranquility, before opening the airlock and removing the hardware used to support the garbage jettison. The crew also took the opportunity to remove and replace a power distribution unit (PDU) in the airlock.

At any given time there are dozens of scientific experiments going on aboard the space station covering a broad range of fields. Some of these require little or no attention from the crew, while others will see the astronauts serving as researchers or research subjects. A key area of research is into how human physiology is affected by long-duration spaceflight – something that is vital for human exploration beyond Earth orbit.

One such experiment, Grip, sought to investigate how the crew’s ability to grip and manipulate objects would be affected by their time in space. Crew time over three days from 5 to 7 July was allocated to this long-running project, which is led by the European Space Agency. Astronauts perform a series of tasks involving holding and moving a test device while seated. Selected crewmembers are required to perform three sessions on Earth before their mission, at least two at different times during their stay in orbit, and four more times after their return to Earth.

Equally important to crew survival on long-duration missions far from Earth is ensuring the astronauts receive the food and water they need to survive without resupply missions. The Exposed Roots On-Orbit Test System (XROOTS) experiment is attempting to grow plants in space without soil. Throughout the month the crew regularly inspected the apparatus and recirculated fluids around it. At the end of the month, the crew proceeded to deactivate the experiment and began work to harvest its crop.

Water for such a long-duration mission would need to be recovered from the crew’s waste. The Forward Osmosis Membrane (FOM) experiment is testing new materials to help extract drinkable water to see how they perform in space.

On 6 July, the crew used the free-flying Astrobee robots to test the Smartphone Video Guidance Sensor (SVGS), a vison-based navigation system designed to determine the location and orientation of objects automatically. Three Astrobee robots, named Honey, Bumble, and Queen, are currently aboard the space station. These cube-shaped devices have been designed to help out with daily operations and research.

In addition to helping out the crew, Astrobees can be used for educational outreach programs, where students are given the opportunity to upload code that will control the robots aboard the station. In July, the Astrobees also participated in a Japan Aerospace Exploration Agency (JAXA) educational challenge within the Kibo module.

During Robo-Pro Challenge 3, teams of students from around the world will use the Astrobees, as well as Japan’s own Internal Ball Camera (Int-Ball) robot, to attempt to solve a series of problems. The scenario simulates an air leak following a collision with orbital debris, with students required to use the robots to illuminate targets, read and analyze information and finally report back to an astronaut. July saw the preliminary round of the challenge carried out on Earth, while the Astrobees were used for a dry run in space. The final round will be held aboard the space station in September.

Samantha Cristoforetti works with two Astrobees during previous research in May (Credit: NASA)

Another key area of research is materials science, with the microgravity aboard the station providing a unique environment in which the crew can study the formation and properties of different materials.

During the first half of the month, the astronauts used the Microgravity Science Glovebox (MSG) to carry out the Universal Intelligent Glass Optics (UNIGLO) experiment. This is a materials processing experiment using artificial intelligence to produce complex glass fibers in microgravity. After setting up the experiment and installing a preform – the rod of raw material from which the fiber is formed – several experimental runs were carried out over the period of a week, with the astronauts replacing the preforms as required between runs.

Optical fibers have been a major point of study aboard the station recently. In addition to UNIGLO, the crew has also been carrying out the Fiber Optic Production 2 (FOP-2) investigation. This builds on earlier research that suggests better quality fibers can be produced in space than on Earth. Like UNIGLOW, FOP-2 was carried out using the MSG, with the crew setting up the experiment on 18 and 19 July, before removing the calibration probe and installing initial preforms and spool modules. The astronauts swapped out the spools and preforms several times over the next few days.

Yet another fiber optic manufacturing experiment was set up in the MSG at the end of the month. Space Fibers 3 and FOP-2 are both aimed at studying the production of fibers from a material named ZBLAN — composed of zirconium, barium, lanthanum, sodium, and aluminum. The first sample run with the new experiment failed, and the crew engaged in troubleshooting efforts including replacing a data cable.

Cargo Dragon arrives at the ISS during the CRS-25 mission (Credit: NASA)

There was just one visiting vehicle movement in July: the arrival of a SpaceX Cargo Dragon spacecraft on 16 July. This marked the third visit to the station by Dragon capsule C208, which docked at the forward port of the Harmony module via PMA-2 and IDA Forward (IDA-F) docking adaptors at 15:21 UTC, having lifted off from the Kennedy Space Center aboard a Falcon 9 rocket 38 hours and 37 minutes earlier.

Dragon was carrying 2,630 kilograms of supplies and equipment as part of the Commercial Resupply Services 25 (CRS-25 or SpX-25) mission, including crew provisions and new scientific research. Dragon’s unpressurized Trunk section contained the Earth Surface Mineral Dust Source Investigation (EMIT), an externally-hosted payload that will be used to study the composition and distribution of dust in the atmosphere, which can have wide-ranging effects on the environment and climate.

EMIT was extracted from Dragon’s trunk along with a replacement Battery Charge/Discharge Unit (BCDU), using the CanadArm2 robotic arm with its Dextre attachment. Extraction was completed on 22 July, with EMIT and the BCDU orbital replacement unit (ORU) being installed on ExPRESS Logistics Carrier 1 (ELC-1) on 24 and 25 July respectively. The station’s crew is responsible for unloading and loading Dragon’s pressurized capsule, which will be recovered at the end of its mission and therefore provides an opportunity to return cargo to Earth. Dragon is expected to depart the space station in August.

At the time of Dragon’s docking, preparations were already in full swing for an extra-vehicular activity (EVA) from the Russian side of the station, which was performed by Oleg Artemyev and Samantha Cristoforetti on 21 July. This was the latest in an ongoing series of spacewalks that have served to commission the Nauka module and its European Robotic Arm (ERA) and was made using Russian Orlan-MKS spacesuits.

Cristoforetti and Artemyev work outside the station during their EVA (Credit: NASA/ESA)

Artemyev and Cristoforetti began their spacewalk from the Poisk module at 14:50 UTC, spending seven hours and four minutes working outside the station. As well as carrying out work on Nauka and the ERA, they also deployed ten small satellites: eight YuZGU-55 experimental satellites for the Southwestern State University (YuZGU) and a pair of Tsiolkovsky-Ryazan spacecraft built in partnership between YuZGU and the Ryazan State Radio Engineering University. These satellites had been delivered to the ISS aboard the Progress M-19M and M-20M cargo spacecraft and were released by hand by Artemyev from a position on the outside of the Poisk module.

With the EVA completed, the crew removed batteries from the spacesuits, inspected and stowed the tethers and tools used, and dried out the spacesuit water lines to ready them for storage. A conference call was also held to debrief on the work that was done during the spacewalk.

Cristoforetti became the first non-Russian to participate in a Russian spacewalk since US astronaut Michael R. Barratt in June 2009 as part of Expedition 20. She was also the first non-Russian to perform a spacewalk from the Poisk module – Barratt’s two EVAs were made from the former Pirs airlock module and within a depressurized section of the Zvezda module, to prepare a docking port for Poisk’s arrival.

The involvement of Cristoforetti in this spacewalk was part of the partnership between the European Space Agency and the Russian Federal Space Agency, Roscosmos, that saw the European Robotic Arm launched along with the Nauka module last year. The arm, which will be able to move between base points on the Russian segment of the space station, is expected to be instrumental in fully commissioning the Nauka module.

The ERA attached to Nauka (Credit: ESA/NASA)

The partnerships at the heart of the International Space Station project have been strained in recent months following Russia’s invasion of Ukraine, with many of the other partner nations having enacted sanctions against Russia or provided assistance to Ukraine in the ongoing war. As July drew to a close, the Russian government announced that it planned to leave the project after 2024.

It is not yet clear whether Russia intends to follow through on this announcement, if so when exactly it would take effect and what the impact would be for the ISS as a whole. A Russian withdrawal is likely to hurt its own space program as much – if not more – than its partners as it will likely take Russia far longer to regain what it is giving up.

While Russia plans to launch its own space station into a polar, sun-synchronous orbit, the first module will not be ready for launch until 2027 at the earliest – assuming its development stays on track. Nauka finally reached the ISS last year, having originally been slated to join the outpost as early as 2007, and while this is an extreme example of how schedules can change in the course of spaceflight megaprojects, Russia will need to devote considerable financial and technical resources to stand any chance of launching its new station on schedule.

In either case, Russia has committed to the ISS until at least the end of 2024. The announcement that they would leave “after 2024” does not rule out extending their participation beyond this date.

Looking ahead to the next month, August will see the end of the CRS-25 mission with the Cargo Dragon spacecraft returning to Earth. In addition to their regular duties and scientific research, the crew will be preparing for another Russian EVA to be performed by Artemyev and Matveev towards the middle of the month.

(Lead photo: The Earth seen from the ISS as it passes over the Persian Gulf in July. One of the USOS solar arrays and the JAXA Kibo module are visible in the foreground. Credit: NASA)

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