NASA has insisted tensions linked to the war in Ukraine had no impact on International Space Station operations or the planned return of an American astronaut aboard a Russian capsule later this month.

Mark Vande Hei is due to fly to the Baikonur Cosmodrome in Kazakhstan aboard a Russian Soyuz capsule with cosmonauts Pyotr Dubrov and Anton Shkaplerov on March 30 after 355 days in space, a new US record.

There have been fears that soaring tensions between the US and Russia over Ukraine could leave the 55-year-old stranded on the outpost.

But speaking to reporters Monday, Joel Montalbano, NASA’s ISS program manager, said: “I can tell you for sure Mark is coming home on that Soyuz. We are in communication with our Russian colleagues. There’s no fuzz on that. The three crew members are coming home.”

“There’s been some discussion about that, but I can tell you we’re ready. Our Roscosmos colleagues have confirmed that they’re ready to bring the whole crew home, all three of them,” he continued.

Over the weekend, Russian space agency chief Dmitry Rogozin warned again that Western sanctions on Russia could cause the ISS to crash, by disrupting the operation of spacecraft vital to keeping the platform in orbit.

But on Monday, the Russian news agency TASS reported: “Russia’s space corporation Roscosmos has never given its partners the slightest chance to doubt its reliability” and Vande Hei would go home as planned.

Montalbano added that there had been no changes in day-to-day activities.

“All these activities have continued for 20 years and nothing has changed in the last three weeks: our control centers operate successfully, flawlessly, seamlessly.”

While the US side of the ISS supplies power and life support, the Russian segment is vital for propulsion and attitude control — interdependencies that were woven into the project from its inception in the 1990s.

The US is exploring means to keep the station in orbit via propulsion from Northrop Grumman and SpaceX ships, but this hasn’t happened yet.

Crew swaps involving Russian cosmonauts going to Hawthorne, California to train on SpaceX vehicles and American astronauts traveling to Star City in Russia to train for Soyuz are still planned “at this time,” said Montalbano.