A Canadian astronaut’s scheduled trip to the International Space Station is in limbo after the spacecraft he was to use failed and made an emergency landing in Kazakhstan.

A Soyuz booster rocket failed shortly after launching on Thursday, forcing two astronauts who were headed to the ISS to make an emergency landing instead. American Nick Hague and Russian Alexei Ovchinin were uninjured, Russian government officials said.

It was not immediately clear what caused the failure. Russia has launched an investigation and suspended all launches of manned spacecraft until the probe is complete.

David Saint-Jacques is scheduled to co-pilot the capsule Dec. 20 and become the first Canadian at the orbiter since now-retired astronaut Chris Hadfield returned to Earth in 2013.

Hadfield told CTV News Channel that he considered it “very unlikely” Saint-Jacques’ launch would go on as scheduled given Thursday’s failure.

“I really would be very surprised,” he said.

“If it’s something simple and easily fixable, then they could get back to flight fairly quickly – but things with rockets are hardly ever simple and easily fixable.”

Even if the Soyuz spacecraft is cleared for launch before December, Hadfield said, it could end up carrying astronauts from Thursday’s launch rather than the next scheduled crew.

“They might be the ones that go, or it might be some mixture. They might need different skills now,” he said in a Periscope video.

The Canadian Space Agency said Thursday that it did not know whether the failed launch would affect Saint-Jacques’ launch date.

“He’s supremely ready to go, and he’ll go as soon as the rocket’s ready,” Hadfield said.

Three astronauts are currently living in the ISS. Hadfield said Thursday’s developments meant they would know they are “in for the long haul.” The station’s supplies of oxygen, food and other consumables would be enough to last the astronauts for years, Hadfield said.

While there is another Soyuz capsule docked at the station, Hadfield said using it to send the current crew home would not be under consideration.

“If you abandon the space station, then there’s no one there to fix things as they fail – and they’ll eventually have a serious problem,” he said.

Saint-Jacques spent time in a Soyuz capsule in August, as part of a disaster training simulation.

Hadfield noted that the launch failure should not be seen as an indictment of the Soyuz rockets, calling mechanical failure part and parcel of space travel. He said failsafe systems operated properly by detaching the astronauts’ capsule from the rocket and returning them to the ground.

“All of the systems that were there in case of a rocket failure worked. It’s not what you want to happen, but it happens,” he said. “I’d fly on the next Soyuz if they asked me to.”

Gov. Gen. Julie Payette, also a former astronaut, called Thursday’s events “a tribute to well designed abort systems and perfectly executed emergency procedures.”

With files from The Canadian Press