CAPE CANAVERAL, Florida The U.S. space agency said on Tuesday it was confident Russia's Soyuz capsules remained safe to use, even as investigators probed an uncomfortably fast and off-course landing of one of the spaceships over the weekend.
The capsule, carrying a NASA astronaut, Russian cosmonaut and South Korea's first astronaut, landed nearly 300 miles (483 km) short of its target just north of Arkalyk, Kazakhstan, and out of sight from recovery teams.
Russia's Interfax news service quoted an unnamed Russian official as saying the returning International Space Station crew was endangered during the Soyuz landing in which they were subjected to about 10 times the force of Earth's gravity -- nearly three times what would normally be expected.
"I don't see this as a major problem, but it clearly should not have occurred," said NASA space flight chief Bill Gerstenmaier.
Space station commander Peggy Whitson and cosmonaut Yuri Malenchenko were returning from a six-month mission aboard the station. They were joined in the Soyuz capsule by a South Korean guest researcher who launched a week earlier in another Soyuz with the replacement station crew.
Upon landing, Malenchenko called the Russian flight controllers on a satellite telephone to notify them that the crew was safe, and rescuers reached the spacecraft after about 45 minutes.
The second spaceship remains docked at the orbital outpost and Gerstenmaier said the capsule was ready to use if the station crew needs to evacuate.
"There is no immediate implication to the Soyuz vehicle on orbit. If we need to return for an emergency case, we can get in the Soyuz and come home," Gerstenmaier told reporters on a conference call.
The next space station crew is not scheduled to launch to the outpost until October, leaving ample time to determine what went wrong during Saturday's landing and to make any repairs, including fixes to the Soyuz in orbit, Gerstenmaier said.
"I have complete confidence in what the Russians are doing. They are treating this with the same diligence that we would," he said.
It was the second consecutive botched Soyuz landing and the third since the ships, which have been flying since the mid-1960s, have been used to ferry crews to and from the space station.
When NASA's three remaining shuttles are retired in two years, the Soyuz will be the only means to transport people to the $100 billion international outpost.
Investigators will analyze flight computers aboard the capsule involved in Saturday's rough landing to determine what happened during the descent.
Gerstenmaier said the investigation likely would take several months.