Why the Inspiration4 all-civilian mission has a better chance of launching

Without space station docking weather constraints have more flexibility

CAPE CANAVERAL, Fla. – Usually, when NASA launches a spacecraft to the International Space Station, the launch window is instantaneous. If the weather or anything else isn’t good right at that very second, it doesn’t go.

But this time, for Inspiration4, it’s not NASA launching and the four civilians are not going to the space station. After launching from Kennedy Space Center the spacecraft will pass the ISS and orbit the Earth for three days before returning.

When NASA started sending American astronauts back to space from American soil on an American rocket last year, the launches looked very different, compared to the days of the Space Shuttle.

The SpaceX capsule cannot land on a runway or in the desert in an emergency as the Shuttle could.

The capsule splashes down somewhere in the ocean and then just floats and bobs with the astronauts inside until rescuers -- typically the men and women of Detachment-3 at Patrick Space Force base -- come to get it.

NASA has a complicated set of weather rules for a crewed rocket launch, involving wave height, wind speed, lightning, clouds and rain up and down the East Coast and across the Atlantic that decides on any given launch day if it’s safe to fly and safe to rescue if needed.

On launch day, NASA monitors weather at 50 different locations from Cape Canaveral, up the eastern seaboard and all the way to Ireland.

Stephen Payne, former Space Shuttle test director in charge of contingency planning, said the decision to launch is never clear cut.

“If the entire path has heavy winds and high seas, that’s an easy decision,” Payne said. “If the path is clear but there’s a patch that’s not so good, perhaps you can adjust your abort range to cut it before or sometime after to avoid that piece. So there’s no real cut and dried answer. There’s a lot of things that have to go into the equation.”

After NASA’s Demo-2 mission with astronauts Bob Behnken and Doug Hurley, NASA eased some of those rules.

The chances of bad weather scrubbing a launch went from 1 in 7 to 1 in 4.

This time though, NASA is not making the rules; in fact, the U.S. space agency is largely uninvolved.

Inspiration4 is entirely a SpaceX mission, meaning the private company is responsible for rescuing the four civilians at sea if the automated capsule triggers an emergency ejection from the rocket.

That also means it’s up to SpaceX when to launch.

This time, the flight path does not take the capsule up to the International Space Station. The Inspiration4 crew has no destination, except space. For three days, the four civilians will just orbit the earth 360 miles up, higher than the space station.

If the waves in the Atlantic Ocean are too big and would make an emergency rescue too dangerous, Spacex could -- if it really wanted to -- change the flight path. Or the private company just launch another time.

SpaceX is planning to launch after 8 p.m. Wednesday.

SpaceX said mission managers will determine a five-hour launch window based on predicted weather conditions at Kennedy Space Center, along the flight path, and at potential emergency landing sites off Florida.