The countdown to the dress rehearsal sets the stage for the launch of SpaceX Crew Dragon

four astronaut launch this weekend aboard a SpaceX Crew Dragon spacecraft tied atop a Falcon 9 rocket at Kennedy Space Center Thursday for a countdown to rehearsal as engineers reviewed preparations and kept an eye on offshore weather in the wake of State of tropical storm.

1-crew commander Michael Hopkins, Victor Glover, Shannon Walker, and Japanese astronaut Soichi Noguchi, wearing futuristic-looking SpaceX pressure suits, were pushed to launch pad 39A at Kennedy Space Center in white Tesla SUVs , just as they will be on Saturday, weather permitting, for a launch at 7:49 PM EST.

With the astronauts tied side by side, monitoring the high-tech touch-screen displays in the Crew Dragon capsule they called “Resilience”, SpaceX’s launch controllers monitored the practice countdown from Firing Room 4 in Launch Control. NASA Center three miles from Pad.

The next major milestone will come on Friday when NASA and SpaceX managers and engineers, following rigorous coronavirus protocols, hold a formal launch readiness review to make a final assessment of the team’s readiness for flight.

Meteorologists predict a 70% chance of acceptable weather Saturday night at the Kennedy Space Center. But the prospects are less certain when it comes to winds and sea states in the Atlantic Ocean along the northeastern trajectory that the Falcon 9 will follow pushing the Crew Dragon into the space station’s orbit.

Relatively calm seas are required for the recovery of the Falcon 9’s first stage, which the company plans to reuse for the next Crew Dragon flight in six months. And generally favorable conditions are needed along the entire flight path in the event of a malfunction that could force the crew to make an emergency crash.

“We are obviously observing the time, time is a big problem, time for more areas”, Kathy Lueders, NASA’s chief of space exploration, told Spaceflight Now on Friday. “The droneship we need where the first stage will land is actually headed today. And with the way the seas are and the way Eta is, we’re looking at how fast that droneship can distinguish it.”

If the droneship is not in station on time, the launch will most likely be delayed.

“The landing time for the first leg is a big deal,” Lueders said. “It’s the stage we’re going to use for Crew-2, so we care. Not that we never care about them, but this is an important stage.”

After passing through Florida on Wednesday, tropical storm Eta was expected to follow a path parallel to the east coast to North Carolina and then into the Atlantic. By Saturday morning, the center of the storm should be well offshore east of Boston.

SpaceX monitors data from approximately 50 buoys along the trajectory measuring winds and wave height, data that will be analyzed before a final decision to proceed with the launch.