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What exactly is a rocket launch window and how is it determined?

Weather, destination and orbital mechanics all play a role

Launch scrubbed; SpaceX to try again Saturday
Launch scrubbed; SpaceX to try again Saturday

BREVARD COUNTY, Fla. – After much anticipation, SpaceX delayed its historic Crew Dragon launch Wednesday about 15 minutes before liftoff because of weather concerns.

Countless hours of planning and preparation go into a single rocket launch. Hundreds plan visits and gather to watch the moment a spacecraft takes off. But how is an exact launch schedule determined?

It all comes down to a science, but because the specifics are different for each mission, there’s not a one-size-fits-all answer.

A launch time is the ideal time to start a mission to get the spacecraft into the correct orbit and the launch window can be instantaneous or last a few hours, according to NASA. The longer the launch window, the higher the potential for using more fuel as the vehicle would need to adjust to get back on track. NASA says the launch window is influenced by many factors, like where the spacecraft is going (the International Space Station, for example), the type of rocket and the goals of the mission.

Weather also plays an obvious role, as was evident in Wednesday’s launch attempt. The 45th Space Wing Weather Squadron gives a weather forecast at the launchpad, but with astronauts on board, there is more to consider. It’s important to also factor in weather forecasts and sea conditions for an abort landing, since the crew would need to be rescued from the water in those instances.

[WATCH BELOW: Digital Journalist Emilee Speck explains how SpaceX chose its launch time]

[RELATED: What happens if NASA astronauts need to abort?]

Daily forecasts are released leading up to the launch and even more frequently the day of. The call for go or no-go can be made almost right up until launch time. More information on forecasting launch and landing weather conditions can be found here.

Wednesday’s launch window was instantaneous -- it was either launch on time or not at all that day, but we won’t have to wait long for the next attempt. The next launch opportunity for the Falcon 9 Crew Dragon is set for May 30 at 3:22 p.m.

[READ MORE: Here are 14 weather reasons SpaceX would not launch the Falcon 9 Crew Dragon]

This historic launch will send astronauts to space from American soil for the first time in almost a decade.

You can catch the Demo-2 mission through News 6′s virtual watch party on ClickOrlando.com. News 6 will have reporters back out at the Space Coast providing live coverage as astronauts Doug Hurley and Bob Behnken head to the ISS. Both President Trump and Vice President Pence are expected to be back in the Sunshine State for the launch, as well.

Stay up-to-date on all space news at ClickOrlando.com/space.


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