Timing of rocket launch impacted by weather, 'orbital mechanics'

It was a major bummer for people anticipating Wednesday's historic rocket launch, but the decision to scrub the manned mission was done for very important safety reasons.

“There are a system of instruments called field mills, and they measure electricity in the atmosphere, and while we weren’t seeing any lightning, we did see some high registrations on those instruments that dictated that there was still electricity in the air,” explained NASA's Kyle Herring,  “and if we had launched into that condition, then we were basically launching a rocket into a situation where it could have initiated some triggered lightning. You don’t want that with any launch vehicle, you certainly don’t want that with a vehicle that has human beings on board.”

So why not wait until later in the day, when the weather was more cooperative?

NASA said it all has to do with "orbital mechanics" and the precise timing needed to rendezvous with another object already in earth's orbit — in this case, the International Space Station.

“Picture the space station in the center lane of a three-lane highway, and that launchpad has to be in that center lane because that rocket has to launch into that same exact plane, that the space station is in,” Herring said.

That means launching in a fixed time frame, on a fixed day.

NASA said the launch window is actually much smaller for a rocket compared to the space shuttle, which had a 10-minute launch window because the shuttle could hold more propellant.

"For smaller rockets with less propellant capability like the Crew Dragon capsule, it can only launch at the exact precise moment to be in the exact precise plane of the International Space Station,” Herring added.

The next launch attempt is scheduled for 3:22 p.m. on Saturday.