A Series of Unfortunate Events

Click the arrow to watch the post-scrub media event. Video source: NASA YouTube channel.

Despite 70% chance of favorable weather, the elements conspired to delay today's Orion EFT-1 launch by 24 hours.

As reported by CNN:

NASA spent most of Thursday morning's nearly 2½-hour launch window trying to work out various obstacles and kinks before scrubbing the launch around 9:40 a.m. ET. The first delay involved a boat that came too close to the launch area; more delays came because of wind gusts.

When the countdown resumed, valves failed to open in the boosters, eventually leading to the scrubbing.

Fueling of the liquid oxygen (LOX) began 175 minutes before launch, and liquid hydrogen (LH₂) at 160 minutes. With a launch window of about 160 minutes, the tanks were filled with super-cold liquids from four to five hours.

Oxygen becomes a liquid at -297° F, and hydrogen at -423° F. It's suspected that the prolonged exposure to these liquids caused the valves to malfunction.