A Yearlong Odyssey: MS-22/23 Prepares to Return Home

As humankind prepares to go further than ever before as part of the Artemis program, space agencies across the world have prepared a series of complex missions to test the limits of the human body. This has produced some of the most dramatic, record-setting space flights that have tested our species’ ability to survive in the harsh environment of space. This past year, however, saw an unexpected addition to the list of record-setting flights – Frank Rubio and the crew of MS-22’s stay on the International Space Station, cementing them on the leaderboard for long duration expeditions at 371 days. This record, however, is not without its own caveats – a disabled Russian spacecraft and ISS operations in jeopardy are only some of the events that resulted in three men staying in space for well over a year.

The International Space Station, at its core, is a proving ground for new technologies supporting human life on and off Earth. While many of the experiments run on station help to monitor our planet and measure our changing world, a sizable chunk is dedicated to studying the long-term effects of spaceflight on humans. Space is a grueling environment for human habitation – temperature flux, radiation and muscle loss are only some of the challenges faced by astronauts as they complete their missions. As humankind prepares to go back to the Moon as part of Artemis, one of the key roles the ISS has played has been studying the impacts of this harsh environment on the human body. One of the most notable experiments conducted was the ISS Year Long Study, also known as the Twins in Space Study. NASA astronaut Scott Kelly, along with Russian cosmonaut Mikhail Korniyenko, spent 340 days onboard the ISS as part of a dedicated psychology and physiology mission. In 2019-2020, Artemis II Mission Specialist Christina Hammock Koch set the record for longest spaceflight by a woman at 328 days. Mark Van de Hei surpassed Kelly’s record with 355 days, which was held until Frank Rubio’s flight as part of Expedition 67/68/69.   

On September 21st, 2022, Soyuz MS-22 launched to the ISS as part of a standard 180 day rotation, with crew members Sergey Prokopyev, Dmitri Petelin and Francisco Rubio. The original all-Russian member crew was named in May 2021. American astronaut Frank Rubio replaced Anna Kikina as a part of the Soyuz-Dragon crew swap system of keeping at least one NASA astronaut and one Roscosmos cosmonaut on each of the crew rotation missions. The mission docked on schedule hours after launch to the Rassvet module on the Russian Segment, and the crew were welcomed by their comrades in orbit. For the first two months of their time in space, the mission was relatively uneventful. Science and spacewalks continued, and the crew of the expedition carried on as normal. On December 15, 2022, a camera on the exterior of the station detected a stream of particles emitting from the Service Module of the Soyuz MS-22 vehicle. This anomaly was concurrent with a loss of pressure in the vehicle’s coolant loop, a vital component for temperature regulation while in space. Work immediately began on isolating the cause, and measuring the impact of such an event. With the loss of coolant, heat became one of the primary issues facing the crew. Temperature sensors immediately noticed a spike in temperature onboard Soyuz MS-22, prompting the crew to seal the hatches. According to tests conducted on the ship’s systems, the temperature in the orbital and descent modules in the first days after the incident reached 30 °C (86 °F), and in the service module 40 °C (104 °F), but by January 2023, the temperature in the whole ship had stabilized at about 30 °C. After the coolant loop had bled dry, closer inspection could be conducted on the vehicle to determine its status. Using the European Robotic Arm, ISS controllers and astronauts onboard began a survey of the spacecraft. Roscosmos Director of Human Spaceflight Sergei Krikalev reported on December 22 that they had identified a several-millimeter-wide hole in the spacecraft, and assessments were underway.

At the same time, conversations in both Houston and Moscow began to assess the safety of the Soyuz vehicle for return, and how severely this would impact operational practices onboard ISS. For as long as the station has been permanently crewed, mission planners have ensured that every astronaut has a way home in the event of an emergency. In short, this means for every astronaut or cosmonaut on station, there is one seat in a spacecraft that is reserved for them – a guaranteed ride home. As the MS-22 situation continued to unfold, however, it would become clear that the spacecraft would not be a safe ride for the crew. Temperatures continued to remain high onboard, and mission planners began to draw the conclusion that the vehicle might present temperatures that could injure the crew on free flight and re-entry. On January 11th, 2023, Sergei Krikalev announced that Roscosmos would fast track the launch of Soyuz MS-23, and bump the scheduled crew to Soyuz MS-24, slated for launch in early September. He said “barring an emergency onboard the ISS, the capsule would not be safe for crew to return in”, leaving the crew without a ride home as they waited for their replacement vehicle. 

ISS controllers, despite the adverse circumstances, continued to work to ensure all of the international crew was safe. Frank Rubio’s custom-molded seat liner onboard Soyuz was relocated to the Crew-5 Dragon, in the event of an emergency onboard the ISS. This was done out of absolute precaution, and to protect the lining from deformation in the high heat environment of the Soyuz. On February 11th, 2023, Progress MS-21, a cargo ship also docked to the station and developed a similar leak, prompting immediate fears of mass quality control issues across the Russian space industry – a worry for international partnerships dependent on Russian parts. Progress MS-21 had been already loaded with waste, and was undocked from the station on February 18th. On February 24th, Soyuz MS-23 launched from Baikonur Cosmodrome to the ISS, providing the necessary replacement for the damaged MS-22. The two Soyuz vehicles remained docked for roughly one month, as the crew offloaded cargo from Soyuz MS-23 and loaded downmass equipment into the departing Soyuz. With the arrival of MS-23, the crew of MS-22’s stay on the ISS was effectively extended by another 6 months. 

MS-22 would depart from the ISS on the 28th of March, for an uncrewed landing on the Kazakh Steppe several hours later. The heat onboard the spacecraft, while higher than nominal, would have certainly been uncomfortable for the crew – but not deadly. Internally, the spacecraft reached a temperature of 122ºF as it descended. This kind of uncrewed return was the second of its kind, with Soyuz 32 returning uncrewed from the Salyut 6 space station in 1979 after an engine issue forced a swap. On September 15, Soyuz MS-24 was launched to the ISS with Oleg Kononenko, Nikolai Chub and Loral O’Hara – joining the crew of Expedition 69, and beginning the transition to Expedition 70. The crew of MS-22/23 has continued their stay in space, with the crew surpassing 365 days on September 21, 2023 – the third-longest continuous stay in human spaceflight history. NASA and partner agencies have been eager to use this opportunity to work with the crew to study long term effects on the human body, something that will be paramount in the years to come with the Artemis Program’s long term goals. But there is an undertone of discomfort – a reminder that space is a harsh and unforgiving environment. In an interview with the New York Times, Rubio said: “One thing that I’ve tried to do, and I hopefully have achieved – I certainly haven’t done it perfectly – is to just kind of stay positive and stay steady throughout the mission despite the internal ups and downs. You just try to focus on the job and the mission and remain steady, because ultimately every day you have to show up and do the work.” However, the end to MS-22/23’s time in space is coming soon, as the crew is scheduled to return on September 27 after 371 days in space, firmly cementing themselves as the third-longest spaceflight in human history. 

With Frank Rubio, Sergey Prokopyev and Dmitri Petelin’s return to Earth planned for September 27, and the crew of Soyuz MS-24 now safely on station, the focus turns to the future of Russian spaceflight and ISS operations. The European Space Agency, NASA, JAXA and CSA have made continued commitments to sustained operations, and are actively working towards the transition to commercial destinations in Low Earth Orbit through the Commercial LEO Destinations program. This, however is not without concerns, and hinges heavily on the Russian segment’s continued support. Reliability on the part of Russian-built components is declining, and the instability of the Russian government threatens to derail political operations on the station. Throughout the last several years, Russian political figures have been willing to make blatant threats to interrupt operations on the station, throwing away more than 25 years of political cooperation in the face of nationalism and the unprovoked war in Ukraine. Politicians have also repeatedly claimed that the station would no longer be a worthwhile economic investment past 2024, and have waffled on the idea of constructing their own station – the Russian Orbital Station. The engineering side also faces an unstable future, as issues continue to crop up on the aging station. Cracks found in various Russian modules have prompted numerous investigations, and a failure to cooperate on investigations has led the ISS partners to be wary of one another. Year-long segments on the Russian side may also become more common, as the cash-strapped Roscosmos attempts to maintain operational cadence onboard the station. Oleg Kononenko and Nikolai Chub will remain on station as Loral O’Hara rotates home at the end of her 6 month stay in space with a short duration crew. If the mission lasts the projected 300-365 days, Kononenko will have spent a total of 1,036-1,101 days in space, exceeding the current record of 878 days by Gennady Padalka. He will also become the first person to stay 1,000 days in space, a record set out of unfortunate necessity for Roscosmos.

For now, the situation on the ISS has returned to some sense of normalcy. Operations continue as systems are upgraded and the 25-year-old station eyes commercial expansions. Crews continue to rotate through the largest orbiting laboratory ever constructed, as humankind prepares to go back to the Moon and on to Mars. The undertone of systematic problems remains, a reminder that not everything is perfect. Cracks, defects and potentially life-threatening issues creep into everyday life, as more and more stopgap measures are introduced to continue operations. For the crew of Soyuz MS-22/23, however, the first breaths of fresh air are only a few days away, an end to a year long odyssey in space.

Edited by Emily B and Beverly Casillas