MINSK (Reuters) - Russian space officials hope to resolve a communications problem on a Soyuz TMA-21 rocket in time for it to carry a Russian-American crew to the International Space Station in early April.
The launch was postponed from March 30 and there still remains the risk it may not go ahead before the April 12 anniversary of man's first space flight, Russia's space agency chief said Tuesday.
Roskosmos director Anatoly Perminov said technicians were working on a faulty transistor that forced the postponement.
If the launch cannot be held by about April 9, he said, it would likely be postponed until after the 50th anniversary of Soviet space pioneer Yuri Gagarin's April 12, 1961 flight, the first human Earth orbit.
Russia will be holding celebrations of the historic flight.
"We will not drive our horses," Perminov said, a Russian expression meaning rush into things.
"You cannot simply replace the transistor. You need to find out why it went out of order, and you need to check this transistor and the whole theory of such transistors before taking a decision about the launch," Perminov said.
He spoke on the sidelines of a visit by Russian Prime Minister Vladimir Putin to Belarus.
The Soyuz TMA-21 is to carry NASA astronaut Ronald Garan and Russian cosmonauts Andrei Borisenko and Alexander Samokutayev to the ISS after it blasts off from Russia's Baikonur launch facility in Kazakhstan.
The delay is likely to increase concerns about relying solely on Russia for rides to the station.
NASA, which is retiring its shuttle fleet after two more flights this year, has relied exclusively on Russian Soyuz craft for space station crew transport since late 2009.
Three members of the space station's current crew are to return to Earth in another Soyuz capsule Wednesday.
The Soyuz TMA-21 mission was named after Gagarin, a major figure in the Cold War space race between the United States and the Soviet Union.
(Reporting by Gleb Bryanski; writing by Steve Gutterman; Editing by Matthew Jones)