MOSCOW, April 27 (RIA Novosti) - Spacecraft...

until a reusable shuttle comes online.

"Before the new Clipper space shuttle is there to take over, we will have to master new digital control systems that we are now installing on Soyuz [craft] instead of analogue parts," Energiya Chief Executive Nikolai Sevastyanov said.

He said only Russian-made systems will be used to upgrade the Soyuz TMA, and that the digital version will be cheaper, lighter and more spacious.

The three-seater Soyuz TMA capsule was the sole vehicle to carry crews to the International Space Station after U.S. shuttle flights were suspended over the Columbia disaster in February 2003, to resume only two-and-a-half years later.

Russia"s next-generation reusable Clipper shuttle, which seats six, is expected to replace the veteran Soyuz by 2015.