BAIKONUR, July 7. /TASS/. The first manned transport spacecraft of a new series Soyuz MS with a crew of three onboard has separated from the third stage of the Soyuz-FG carrier rocket and is heading for the International Space Station (ISS), a spokesman for Russian state space corporation Roscosmos said.

"The spaceship separated from the carrier rocket, went into orbit and set its course for the ISS," the spokesman said.

The spaceship is scheduled to dock to the ISS’ Russian segment in a span of two days, at 07:12 a.m. Moscow time on Saturday. It will take a crew of Russian cosmonaut Anatoly Ivanishin, Japanese astronaut Takuya Onishi and NASA astronaut Kathleen Rubins to the International Space Station (ISS).

It will be the first spaceflight for Rubins and Onishi and the second one for Ivanishin, who spent 165 days in the ISS in 2011-2012. The three were initially planned to fly to the ISS onboard the last spacecraft of the previous series, Soyuz TMA-20M. However the program of flights was changed late in 2015 and the three crew members had to undergo a retraining course to be able to work with the systems of the modernized Soyuz MS.

Soyuz MS introduces a number of systems upgrades on the time-tested Russian spacecraft, primarily focused on the vehicle’s navigation, control and communications system. The modified systems were tested in an operational environment aboard two Progress cargo missions starting in December 2015 to fully check out all new components in space before committing to a crewed flight.

The MS modification replaces the old Kvant radio system of Soyuz with a Unified Command and Telemetry System and the new communications system enables Soyuz to use the Luch data relay satellites to keep in contact with mission control for the majority of its treks around the planet.

The Soyuz MS was to be launched back in May but was several times postponed. One of such postponements was due to software problems.

Ivanishin, Rubin and Onishi will conduct 39 experiments in such areas as space biology and biotechnologies. They will also conduct tests under the program of developing new polymeric materials capable of resisting fungal and bacteria colonies.