The launch could occur as early as 8:02 p.m. But the action will begin hours before that.

If the schedule is similar to SpaceX’s earlier NASA astronaut flights, then about three and a half hours before the launch, the crew will begin donning their customized SpaceX spacesuits. Once technicians have confirmed the suits are properly fitted, the four astronauts will say goodbye to their families and be transported to the launchpad.

Approximately two and a half hours before the flight — around 5:30 p.m. Eastern time — the crew will board the Crew Dragon capsule. SpaceX technicians will then complete a number of procedures before sealing them inside the spacecraft, a process that could take about an hour.

About 45 minutes before the scheduled launch time, SpaceX will start loading propellent into the rocket and begin making final checks of the spacecraft’s systems and the weather to decide whether it is safe for the mission to launch.

Once the rocket launches, the capsule will begin a series of steps to be lifted to orbit, including separating from the rocket’s first and second stages. In the hour or so that follows, the spacecraft will fire its thrusters, setting it on the course it will follow until the astronauts return to Earth on Saturday.