BAIKONUR, Kazakhstan (AFP) — An American astronaut and two Russian cosmonauts are set to blast off to the International Space Station Wednesday on a Russian-operated flight despite soaring tensions between Moscow and Washington over Russia's invasion of Ukraine.

National Aeronautics and Space Administration's Frank Rubio and Russia's Sergey Prokopyev and Dmitry Petelin are scheduled to take off from the Russia-leased Baikonur cosmodrome in Kazakhstan at 1354 GMT, according to Russian space agency Roscosmos.

Rubio will become the first United States astronaut to travel to the ISS on a Russian Soyuz rocket since President Vladimir Putin sent troops into pro-Western Ukraine on 24 February.

In response, Western capitals including Washington have hit Moscow with unprecedented sanctions and bilateral ties have sunk to new lows.

However, space has managed to remain an outlier of cooperation between the two countries.

Following Rubio's flight, Russia's only active female cosmonaut Anna Kikina is expected to travel to the orbital station in early October aboard a SpaceX Crew Dragon.

She will become only the fifth professional woman cosmonaut from Russia or the Soviet Union to fly to space, and the first Russian to fly aboard a spacecraft of SpaceX, the company of US billionaire Elon Musk.

With both flights set to go ahead, Russian cosmonauts and Western astronauts have sought to steer clear of the conflict that is raging back on Earth, especially when in orbit together.

Russia leaving ISS
A collaboration among the US, Canada, Japan, the European Space Agency and Russia, the ISS is split into two sections: the US Orbital Segment, and the Russian Orbital Segment.

At present, the ISS depends on a Russian propulsion system to maintain its orbit, about 400 kilometers above sea level, with the US segment responsible for electricity and life support systems.

However, tensions in the space field have grown after Washington announced sanctions on Moscow's aerospace industry — triggering warnings from Russia's former space chief Dmitry Rogozin, an ardent supporter of the Ukraine war.

Rogozin's recently appointed successor Yuri Borisov later confirmed Russia's long-mooted move to leave the ISS after 2024 in favor of creating its own orbital station.