Russian and United States space officials said the crew made an emergency landing in Kazakhstan at an unspecified time.
An incident took place during the October 11 launch of a Soyuz spacecraft carrying two men to the International Space Station, with the status of the spacecraft and crew now unknown.
Hague and Ovchinin will open the hatch to their spacecraft at 12:45 p.m. EDT (1645 GMT), when they will be greeted by their three Expedition 57 crewmates: NASA astronaut Serena M. Auñón-Chancellor, European Space Agency astronaut Alexander Gerst and Russian cosmonaut Sergey Prokopyev.
Citing Russian military sources, it said four Mi-8 helicopters had been seen heading for the landing site via Kazakh airports. The launch appeared to be normal until around first stage separation, when the crew reported a "failure" with the booster and feeling weightlessness.
Russian and USA space officials said that the crew is heading for an emergency landing in Kazakhstan at an unspecified time.
"Search and rescue teams are en route to the landing location and we await further updates".
The Russia Soyuz rocket was carrying a Russian and U.S. astronaut on board.
Ovchinin spent six months on the station in 2016.
Relations between Moscow and Washington have sunk to post-Cold War lows over the crisis in Ukraine, the war in Syria and allegations of Russian meddling in the 2016 US presidential vote, but Russia and the USA have maintained cooperation in space.