MOSCOW (AP) — A software glitch on a Russian spacecraft heading to the International Space Station has delayed the arrival of three astronauts, including an American.

NASA said the crew was in no danger, and the U.S.-Russia space partnership was strong despite tensions over Ukraine.

The Soyuz spacecraft carrying Russians Alexander Skvortsov and Oleg Artemyev and NASA's Steve Swanson blasted off successfully early Wednesday and was scheduled to dock six hours later. Because of the glitch, the trip will now take two days.

Since the 2011 retirement of the U.S. space shuttle fleet, NASA has depended on the Russian spacecraft to ferry crews to the orbiting outpost and is paying Russia nearly $71 million per seat. This cooperation has continued despite tensions over Russia's annexation of Crimea and U.S. calls for harsher sanctions on Russia.

NASA Administrator Charles Bolden repeatedly has said that the conflict in Ukraine would have no effect on the U.S.-Russian partnership. As recently as Tuesday he reiterated on his blog that while NASA continues to cooperate successfully with Russia, it wants to resume launch crews from U.S. soil. NASA is trying to speed up private American companies' efforts to send crews into orbit, but it needs extra funding.

The Soyuz booster rocket lifted off at 3:17 a.m. local time Wednesday (2117 GMT Tuesday) from the Russian-leased Baikonur cosmodrome in Kazakhstan. It reached orbit about 10 minutes later.

NASA and Roscosmos, Russia's space agency, said shortly before the scheduled docking that the arrival had been delayed. A 24-second engine burn needed to adjust the Soyuz spacecraft's orbiting path "did not occur as planned."

The docking of Soyuz TMA-12M at the space station is now scheduled for 7:58 p.m. EDT Thursday (2358 GMT).

Roscosmos chief Oleg Ostapenko said on Wednesday the problem was in the ship's orientation system. The crew took off their spacesuits to prepare for the long flight, Ostapenko said in remarks carried by Russian news agencies.

Later Wednesday, NASA said in a press release that "initial information indicates the spacecraft was not at the proper attitude, or orientation, for the automated thruster." The space agency said Russia had confirmed that two maneuvers were completed to put the capsule on course.

Until last year, Russian spacecraft used to routinely travel two days to reach the orbiting laboratory. Wednesday would have been only the fifth time that a crew would have taken the six-hour "fast-track" route to the station.

The new crew will join Japan's Koichi Wakata, NASA's Rick Mastracchio and Russia's Mikhail Tyurin, who have been at the station since November. The new crew is scheduled to stay in orbit for six months.

NASA said the delay was not expected to change plans to launch a supply ship to the space station from Cape Canaveral, Fla., on Sunday night.

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AP writer Vladimir Isachenkov contributed to this report.

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NASA: http://1.usa.gov/1gUPUHl