NASA cites progress in reducing air leaks on the ISS

WASHINGTON – NASA is downplaying concerns raised in a recent report about a long-standing air leak in the Russian segment of the International Space Station, saying it has recently reduced the leak rate.

A report from NASA’s Office of Inspector General released Sept. 26 said the ISS program in June classified a leak in a section of Russia’s Zvezda module “at the highest risk level in its risk management system.” NASA uses a system that rates both the likelihood and severity of a risk on a scale of one to five. The leak was rated a five in both cases.

That assessment came after NASA reported that the leak increased in February in an antechamber of the service module known as PrK, which separates a docking port from the rest of the module. The leak was first discovered in 2019 but had recently doubled. By April, the OIG report said the leak had grown to nearly 1.7 kilograms per day, the highest rate ever recorded.

At a Sept. 27 briefing before the launch of the Crew 9 mission to the ISS, NASA officials said there had been progress in reducing the leak rate. Robyn Gatens, director of the ISS program at NASA Headquarters, said recent repair work had reduced the leak rate by about a third.

“We will continue to work with them to understand the causes of the leak and how they affect the operations of the space station,” NASA Associate Administrator Jim Free said of working with Roscosmos to investigate the leak.

The root cause of the leaks remains under investigation, but “both agencies have narrowed their focus to internal and external welds,” the OIG report said, adding that similar leaks were not found anywhere else on the station.

Station staff keep the hatch to the PrK closed when not in use to mitigate the impact of the leak. If the leak worsens, a long-term solution would be to close the hatch permanently, but that would deprive the station of a docking port used by the Progress and Soyuz spacecraft.

“According to NASA, Roscosmos is confident that they will be able to monitor and close the hatch to the service module before the leak rate reaches an unsustainable level,” the report said. “However, NASA and Roscosmos have not reached agreement on the point at which the leak rate becomes unsustainable.”

According to the OIG report, the PrK leak was one of several challenges NASA faced in keeping the ISS operational through the end of the decade. It also cited potential supply chain problems in sourcing spare parts for ISS repairs, ongoing problems certifying Boeing’s CST-100 Starliner to provide redundant crew transport capacity, and growing risks from debris in orbit.

The report also identified problems with the end of the ISS itself. NASA awarded SpaceX a contract in June to develop a deorbit vehicle for the ISS based on the company’s Dragon spacecraft. The deorbit vehicle will provide the final push for a controlled re-entry into the station and will target a 2,000 kilometer long corridor in the open ocean.

However, the report says that the development of this deorbit vehicle involves budget and schedule risks that raise doubts that it will be ready by the end of the decade. It was noted that the current schedule calls for the launch of the deorbit vehicle five and a half years after the contract award, while the average time for major NASA space programs from award to launch is eight and a half years. According to OIG, NASA hopes that using a derivative of the existing Dragon spacecraft will shorten this timeline.

OIG also stated that the deorbit plans also assume that Russia will remain involved in the station and contribute two Progress vehicles. Roscosmos has agreed to cooperate on the ISS only until 2028, which officials said was previously linked to Russia’s policy of extending the station for four-year periods. NASA officials told OIG that they expect discussions with Roscosmos on deorbit plans to intensify in 2025 and 2026.

“However, without Russia’s commitment to the current deorbit plan, the ability to conduct controlled deorbit is unclear,” the report warned.

Related