Search-and-rescue teams were headed to the area where the capsule was expected to come down for what a NASA TV announcer said was likely to be a "hard landing".
NASA Television reported that the spacecraft was in a ballistic descent after apparently separating from the Soyuz rocket, making a return to Earth rather than heading to the International Space Station.
But they got into trouble and were forced to make an emergency exit.
It comes weeks after a hole was discovered in the International Space Station amid talk from the Russian space authorities of deliberate sabotage.
They were to dock at the orbiting outpost six hours later, but the booster suffered a failure minutes after the launch. "The teams are en route to the landing site".
"We had an interruption on today's launch", a NASA commentator reported.
"Teams have been in contact with the crew".
They set the trajectory for the flight, and if they aren't running at full capacity could send the rocket in completely the wrong direction.
Once separated during an emergency landing, the module will fire its parachute and float back to Earth.
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