The International Space Station (ISS) seems to be showing its age. Or at least the older modules that have been in space since 1998. According to a high-ranking Russian space official, cosmonauts on board the ISS discovered new cracks in the Functional Cargo Block (FCB) module. Zarya (“dawn”). These cracks were found in seven of the module’s twenty windows and could eventually threaten the entire station.
The Zarya module was the first component launched for the International Space Station ISS. While funding was provided through a NASA subcontract with Boeing and the module is part of the U.S. section, the module itself was provided by the State Research and Manufacturing Center for Research and Production (KhSC) in Russia (a subsidiary of Energia Rocket and Space Corporation ) and Roscosmos was responsible for the introduction in 1998.
Zarya was also responsible for providing electrical energy, storage, propulsion and guidance of the ISS during the initial assembly phase. Unfortunately, after twenty-three years in space (and twenty-one in continuous operation), the module begins to suffer from its structural problems. And in space, the worst structural problem imaginable is finding cracks in the fuselage.
The Russian cargo module Zarya in orbit before integration into the ISS. Photo credit: NASA
The news on this matter came from Vladimir Soloviev, the general designer of Energia RSC – which designed and built all modules in the Russian segment. As Soloviev told the Russian news agency RIA Novosti:
“Superficial cracks were found in some places on the Zarya module. This is bad and indicates that the cracks will spread over time … In this context, we have introduced a new method of measuring the deflection of glass. They can of course be covered with sealed covers, but what’s the point of flying at the train station without a window? ”
Soloviev didn’t say whether or not the rifts pose a decompression stop, but he previously said that much of the ISS’s equipment is aging and at risk of experiencing an “avalanche” of failures beyond 2025. The operating license was extended to 2030 and funding was secured until the end of 2025. However, recent engineering issues lead some to conclude that the ISS may not last as long.
In September 2019, the crew of Expedition 63 registered a drop in internal pressure and spent the next year locating the source. The leak was ultimately traced back to the intermediate chamber of the Russian Zvezda module, which was repaired by March 2020. While this leak did not threaten either the station or the crew, another leak was later identified that was quenched – but not fully repaired.
Image of the ISS in orbit. Photo credit: NASA
Back in January, Soloviev reported that the leak caused a pressure drop of 0.4 millimeters of mercury per day. In terms of air pressure, 760mm is the same as the atmospheric pressure here on earth at sea level – or 101,325 Pascal (Pa). This results in a pressure loss of 0.005 Pascal (0.0005%) per day, which requires that the station is supplied with reserves that are both present on the ISS and are transported from the earth.
Last month, the ISS also suffered a software bug that resulted in the Nauka module’s engines being accidentally re-ignited a few hours after docking. This was responsible for temporarily driving the ISS out of position, forcing the Orbital Flight Test-2 (OFT-2) mission to be delayed. Last month, Roskosmos also reported a further drop in air pressure in the Zvezda service module.
Roscosmos has pledged to remain a partner in the ISS program through 2024 and has signaled that they may be ready to expand their participation beyond that. However, Russia has also expressed interest in building its own orbital space station to replace the ISS from 2025. Last year Russia said it would not sign the Artemis Agreement, which obliges it to participate in NASA’s Artemis program.
According to statements made at the time, Russia’s refusal was based on the fact that the agreements were “too US-centered” and political, but also deviated from the spirit of cooperation embodied in the ISS program. Russia has since announced a new partnership with China to create an International Lunar Research Station (ILRS), followed by the release of a roadmap and timeline for development – the International Lunar Research Station (ILRS) Guide for Partnership.
It’s sad to admit, but the days of the ISS are numbered. This certainly seems to be the consensus among NASA, Roscosmos, and the thirteen other member states that have participated in the ISS since its inception. But in its twenty-one years of continuous operation, the station has enabled all kinds of scientific research, experimentation, and breakthroughs.
As the only dedicated microgravity research environment, the ISS has enabled experiments in areas from astronomy and astrobiology to materials science, space weather and medicine. In addition to space agencies, commercial establishments, research institutes and universities have also managed to benefit from its continued operation. Above all, the station has repeatedly served as a means of promoting cooperation between nations and space programs.
Knowing that the ISS has not been around for long (so to speak) and is likely to be replaced by multiple space stations owned and operated by competing power blocs is certainly daunting. But before the ISS reaches the end of its service and leaves its orbit, hopefully those who helped make it a reality will find a way to keep alive the spirit of collaboration it embodies.
Further reading: Reuters, RIA