It appears that the International Space Station is showing its age. Or, at least, the older modules that have been in space since 1998 certainly are. According to statements made by a senior Russian space official, cosmonauts aboard the ISS have discovered new cracks in the Functional Cargo Block (FCB) module – aka. 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. While funding was provided through a NASA subcontract with Boeing and the module is part of the US section, the module itself was built by the Khrunichev State Research and Production Space Center (KhSC) in Russia (a subsidiary of Energia Rocket and Space Corporation) and Roscosmos was responsible for launching it in 1998.
Zarya was also responsible for providing electrical power, storage, propulsion, and guidance to the ISS during the initial stage of assembly. Alas, after twenty-three years in space (and twenty-one in continuous operation), the module is beginning to suffer from its share of structural problems. And in space, the worst structural problem imaginable is to find cracks forming in the fuselage.
The Russian Zarya cargo module in Earth’s orbit before being integrated into the ISS. Credit: NASA
News of the issue came from Vladimir Soloviev, general designer of Energia RSC – which designed and built all of the modules in the Russian segment. As Soloviev told the Russian news agency RIA Novosti:
“Superficial fissures have been found in some places on the Zarya module. This is bad and suggests that the fissures will begin to spread over time… In this regard, we have introduced a new procedure for measuring the deflection of glass. They, of course, can be covered with sealed covers, but what is the point of flying at the station without windows?”
Soloviev did not say whether or not the cracks posed any decompression danger, but he did say previously that much of the ISS’ equipment is aging and in danger of experiencing an “avalanche” of failures beyond 2025. As of December 2018, the ISS’ operation authorization was extended to 2030, and its funding was secured until the end of 2025. However, the recent string of technical problems is leading some to conclude that the ISS may not last that long.
In September of 2019, the crew of Expedition 63 recorded a drop in internal pressure and spent the next year trying to locate the source. The leak was eventually traced to the intermediate chamber of the Russian Zvezda module, which was repaired by March 2020. While this leak did not threaten the station or crew, another leak was identified later that was staunched – but not repaired entirely.
Image of the ISS in Earth orbit. Credit: NASA
Back in January, Soloviev reported that the leak is causing a pressure drop of 0.4 millimeters of mercury per day. In terms of barometric pressure, 760 mm is the equivalent of the atmospheric pressure here on Earth at sea level – or 101,325 pascals (Pa). That works out to a pressure loss of 0.005 pascals (0.0005%) a day, which requires that the station be pressurized with reserves, which are available on both the ISS and are transported from Earth.
Last month, the ISS also suffered a software glitch that caused the thrusters on the Nauka module to inadvertently reignite a few hours after it had docked. This was responsible
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