Signs have appeared that the Korean who is slated to become the first Korean in space, Ko San, will be replaced by his female backup Lee So-yun.
Sources close to the situation said Sunday that Lee was transferred to the official boarding team Friday to begin training there in place of Ko, adding Lee could replace Ko in the Russian Soyuz mission.
Lee is confirmed to have undergone onboard training Friday with two cosmonauts who trained with Ko at Moscows Gagarin Center.
Ko was selected as his countrys first to travel in space. Both he and Lee received separate training with different Russian crews, but their roles have since changed.
They are also known to have unable to leave the center Saturday or Sunday, the last two days which they were allowed out, due to a ban by the Russian side.
Baek Hong-ryeol, head of the Korea Aerospace Research Institute, recently visited the center and coordinated the training with the Russian side. Officials from Koreas Education, Science and Technology Ministry also summoned emergency meetings successively from Thursday.
If Lee goes into space instead of Ko, the likely reasons are Kos health or a mistake in the course of training.
But experts say the project to produce Korean astronauts will proceed without fail even if the astronaut is changed. Lee has been undergoing training for unexpected occurrences.
The Russian side will hold final tests March 17 and 18 and select either Ko or Lee as the first Korean to board Soyuz on March 19.