SpaceX seems to be ready for the launch of its iconic spacecraft, the Crew Dragon, on Wednesday.

The only obstacle, however, seems to be the weather. The original plan was for Douglas Hurley (Crew Dragon commander) and Robert Behnken (joint operations commander) to head to the 39A launchpad at around 1:15 p.m. Eastern Time on Wednesday. They will be taking their seats inside the Crew Dragon at around 2 p.m. By 4:33 p.m., take-off would have occurred, coordinated with Earth’s rotation so that the launchpad is properly partitioned. These plans may be amended given the weather outlook.

On Monday, engineers at SpaceX continued with preparations for the launch of the Crew Dragon. Two astronauts will be sent along, making this the first piloted spacecraft to be sent from the US in the past nine years.

There are two important preparations SpaceX is making in partnership with other space organizations like NASA. Recently, the Falcon 9 launch vehicle was deemed ready for take-off post a launch readiness review conducted by SpaceX and NASA.

The second preparation was done to ensure that the two astronauts are ready for flight. Arrangements were made to welcome them into NASA’s laboratory complex.

Everything that could be controlled is under control. Monday’s discussion verified that all the technical aspects were taken care of. Now, the team is only hoping that the weather conditions would also improve.

They seem to be in luck. Mike McAleenan, the launch weather officer at SpaceX with the 45ht Weather Squadron, said that weather is also showing signs of clearing up. This is a much more optimistic prediction than the forecast that there is 60% probability of the launch being hindered by the weather. McAleenan said that this probability is now likely at 40%. Although it is raining more and there might be some thunderstorms on Wednesday, the cloudiness is significantly lower.

The spacecraft will be flying along the Atlantic Ocean. As a safety measure, the commanders can ditch the Crew Dragon in the case of a disaster like the failure of the launch vehicle. However, the situation down there is still uncertain and McAleenan said nothing about it either.

Nevertheless, the spacecraft has an in-built emergency abort system. Hurley and Behnken will equip it around 40 minutes before the propellant is loaded into the tank.

There are several weather-related factors that are analyzed before the schedule of a take-off. SpaceX, with its highly advanced weather detection system, will use a variety of tools- such as weather/climate models, data from high-altitude balloons, wind, rain and water wave data, and ground-trace buoys- for this multivariate analysis.

As stated by Hans Koenigsmann, vice president of build and flight reliability, the last weather appraisal will be done before this emergency abort system is armed. If there are serious doubts about whether the conditions will favor the launch, the propellant loading will be canceled and the liftoff will be rescheduled.

Koenigsmann said that they always conduct these checks up until the very last minute, going “all the way down to the wire.” The judgement about the suitability of the launch is left to McAleenan. However, they will not be following this procedure this time as it would put the crew at unnecessary risk.

For the launch of this flight, the last check will be made 45 minutes before the propellant loading. It will also be done four and six hours before this, but the final decision would have been made by the time they are arming the abort system.

In the event of a postponement, the next launch timings are 3:22:41 p.m. Saturday and 3:00:07 p.m. Sunday. These are determined by the space station’s orbit and how well (and quickly) the spacecraft can reach the laboratory complex at NASA.

McAleenan said that these two dates seem much less risky, especially in the Atlantic, than the 27th, although anything can happen in the next day.