Less than two days after Orbital ATK’s successful launch to the International Space Station, another rocket is headed the same way. Early Wednesday morning, a Russian Soyuz rocket will take off from Kazakhstan, transporting three new crew members to the ISS.

The trio launches tomorrow at 4:05AM ET

On board the flight will be NASA astronaut Shane Kimbrough, as well as Russian cosmonauts Sergey Ryzhikov and Andrey Borisenko. Once the trio launches Wednesday at 4:05AM ET, they’ll travel in space for a couple days, testing some upgraded systems aboard the Soyuz. Then on Friday, the capsule will hook up to the ISS at around 5:59AM ET, with the crew entering the station around two and half hours later.

The launch will bring the total number of people aboard the station to six — but not for very long. The three crew members already onboard the ISS are set to head home in less than two weeks on October 29th. Meanwhile, the newcomers will stay on the station for about four months, leaving sometime in late February.

Wednesday's launch was originally supposed to take place on September 23rd, but was postponed because of technical problems with the Soyuz. There were hints that a short circuit was to blame, but the Russian Federal Space Agency says it has fixed the issue. Now, since this launch is happening so soon after the Antares launch, it’s causing a bit of a traffic jam in space. The Cygnus cargo capsule that launched on the Antares will have to loiter in orbit for a little while until after the astronauts on the Soyuz make it to the ISS safely. Then on Sunday, the Cygnus will finally dock with the station.

If you’re on the East Coast and plan to pull an all-nighter, NASA’s coverage of the launch begins at 3:15AM ET.