A Russian Soyuz booster arrived at the launch pad on the Kazakh steppe on Sunday, making its final stop before the liftoff on Wednesday with three people aboard the International Space Station.

A Soyuz-2.1A rocket took off from an assembly building at sunrise on Sunday for a railway trek at the Bikonur Cosmodrome in Kazakhstan. Upon arrival at the Soyuz Pad, the hydraulic cylinders were lifted into position around the launcher by a three-stage rocket vertical and gantry arms.

In the final hours before launch, ground crews began final testing, engine preparations, and closeouts before the Soyuz rocket was filled with kerosene and liquid oxygen propellants. The lift was set for EDT (0545 GMT; 10:45 am Baikonur time) at 1:45 a.m. Wednesday.

Two Russian astronauts and a US astronaut will launch the Soyuz MS-17 spacecraft into orbit, a two-orbit orbiter with the space station. Assuming a timely launch, the crew capsule will be connected to the space station’s Rasvet module at 4:52 a.m. EDT (0852 GMT).

The launch from Bikonor was the moment the space station flew directly over the spacecraft in Central Asia.

Commander Sergei Rykov will board the middle seat of the Soyuz MS-17 spacecraft’s three-hour space station. Raikov, 46, is a former MiG-29 fighter jet of the Russian Air Force and an expert on a former aircraft when it entered orbit for 173 days in 2016 and 2017.

Russian astronaut Sergei Kud-Sverkov will take the Soyuz left-hand seat and act as primary flight engineer. Kud-Sverkov, 37, is the first astronaut to join the Russian Cosmonaut Corps in 2010 after working as a rocket engineer at Energy, Russia’s main contractor for the human spaceflight program.

NASA astronaut Kate Rubins will take a seat in the right seat inside the Soyuz crew capsule. Born in Connecticut and raised in California, Rubins will begin his second exploration of the space station in 2016 on his 42nd birthday after a 115-day mission. He holds a PhD in Cancer Biology, worked in public health, and studied infectious diseases before being selected as a NASA astronaut in 2009.

The three-member team will be joined by space station commander Chris Cassidy and Russian Kromats Anatoly Ivanishin and Ivan Wagner for the week-long hangar. Cassidy, Ivanishin and Wagner return to the landing on October 21 with the help of a parachute from Kazakhstan. Their Soyuz MS-16 spacecraft has been in orbit for more than six months.

Rishikov, Kud-Sverkov and Rubins will spend six months working on the space station. They return to Earth on April 17th.

Four more astronauts will be launched from NASA’s Kennedy Space Center in Florida aboard the SpaceX Crew Dragon spacecraft from November to mid-November. That would increase the size of the space station crew to seven.

More photos of the launch pad of the Soyuz rocket are posted below.

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