Russia’s Roscosmos state space corporation announced today that the launch of Soyuz MS-02, scheduled for Friday, has been postponed for technical reasons. A new launch date will be announced later. This is the second flight of this new version of the Soyuz spacecraft. The first also was postponed close to launch.

Roscosmos posted the news on its website, saying (using Google translate): “Roscosmos decided to postpone the planned September 23, 2016 launch of the spacecraft ‘Soyuz MS-02’ for technical reasons after routine tests at the Baikonur Cosmodrome. The launch date of the spacecraft will be announced later.”

Soyuz MS-02 will take three crew members to the International Space Station (ISS): NASA’s Shane Kimbrough and Roscosmos’s Andrey Borisenko and Sergey Ryzhikov. When they do launch, they will join three ISS crew already aboard: NASA’s Kate Rubins, JAXA’s Takuya Onishi, and Roscosmos’s Anatoly Ivanishin.

This is second flight of this new version of the Soyuz spacecraft — Soyuz MS — which replaced the Soyuz TMA-M series. The first Soyuz was launched in 1967 and it has gone through several modifications over the decades, each with its own designation. The MS version has improved solar arrays, a new digital computer, and a new docking system among other upgrades.

The first Soyuz MS launch, Soyuz MS-01, also was delayed. The reasons were never officially speciified, but indications were that it was an issue with the docking system. Originally scheduled for June 24, it launched on July 7 instead. Because this is a new version of Soyuz, the decision was made to take the longer 2-day trajectory to ISS to check out the spacecraft instead of the abbreviated 6-hour route used in recent years. Soyuz MS-02 also will take the 2-day path.

Soyuz spacecraft have been the only means for taking crews to and from ISS since the United States terminated the space shuttle program in 2011. NASA is engaged in public private partnerships with SpaceX and Boeing to build new “commercial crew” vehicles — Crew Dragon and CST-100 Starliner, respectively — that NASA hopes will begin routine flights in 2018 (test flights may occur next year). Until then, Soyuz is the only one. Soyuz is launched from the Baikonur Cosmodrome in Kazakhstan.