On Tuesday, September 29, the Russian State Space Corporation (Roscosmos) announced that astronauts aboard the International Space Station (ISS) had found the source of a suspected leak. Expedition 63 crew – NASA astronaut and commander Chris Cassidy and Russian cosmonauts Anatoly Ivanishin and Ivan Vagner – had been looking for this leak since August and determined it was “beyond expected levels”.
Roscosmos also said in a statement that “it has been determined that the spot is in the Zvezda (star) service module, which contains scientific equipment.” They also pointed out that the loss “is not dangerous to the life and health of the ISS crew and does not prevent the ISS from continuing manned flight.”
The leak was isolated on Monday night (September 28) thanks to the efforts of the crew and analyzes conducted by the ground mission control teams. It started with leak checks conducted in the US segment of the station, which included US, European and Japanese modules. Commander Cassidy, Ivanishin, and Vagner were then tasked with moving into the Russian segment to collect data from various locations.
They proceeded to close the bow and stern hatches and the Zvezda passages that connect to other modules, then used an ultrasonic leak detector to collect the data. Meanwhile, US and Russian specialists took pressure measurements throughout the night to try to isolate the source of the leak. Having done this, the crew reopened the hatches between the US and Russian segments and resumed normal activities.
The size of the leak has since been attributed to a temporary temperature change aboard the station, but the overall leak rate has apparently remained unchanged. Sergei Krikalyov, the executive director of Russia’s manned space programs, pointed out that it will take some time to find it, but that the ISS always has a slight air leak due to the air purification system:
“These losses are predictable. What’s happening now is more than the normal leak, and of course, if it lasts long, it will require extra air supplies to the station … [The source is] not for sure. We have time. The loss obviously exists. It’s not good that it’s there, but it’s not essential “.
Since then, Roscosmos has released new information, saying they should further isolate the escape location. According to their latest findings, it is located in the transfer chamber, one of the four sections of the Zvezda service module. They also reiterated that “the loss does not pose an immediate danger to the crew at the current loss rate and will only result in a slight deviation from the crew schedule”.
This isn’t the first time astronauts aboard the ISS have had to contend with losses at the station. In August 2018, Expedition 56 crew members found a hole in the wall of a Russian-made Soyuz space capsule that had docked at the ISS. Although Roscosmos announced in 2019 that it had determined the source of the leak, it has not yet made the information public.
Meanwhile, the ISS received an unmanned Cygnus freighter over the weekend, launched from NASA’s Wallops Flight Facility in Virginia. This cargo includes a new space toilet – the Universal Waste Management System (UWMS) – and a series of science experiments and technology demonstrators designed to advance everything from medicine to nutrition in space.
These include the ammonia electrooxidation experiment, which can transform ammonia into drinking water and electricity; the Plant Habitat-02 experiment, which will grow radishes aboard the ISS; the Onco-Selectors survey, which will test cancer treatments in microgravity conditions; a 360-degree camera that will record footage for NASA’s VR ISS Experience; and the Rhodium Space Rhizosphere experiment which will test how different soil types behave in microgravity conditions.
The ISS crew is also awaiting the next launch of Expedition 64 astronauts who will replace them aboard the station. This crew will consist of cosmonauts Sergey Ryzhikov (commander) and Sergey Kud-Sverchkov (flight engineer 2) and NASA astronaut Kate Rubins (flight engineer 1). All are currently at the Baikonur Cosmodrome in Kazakhstan and are preparing for the launch on Wednesday 14 October.
Further reading: Phys.org