Lots of talk about the launch criteria with respect to #Demo2 #LaunchAmerica today, especially as it relates to #lightning - and with good reason. (Photo: @NASA, Sam Walton)

One year ago, a #Soyuz rocket triggered lightning during its launch and was struck by a 140 kA positive stroke https://twitter.com/COweatherman/status/1133708452935680000?s=20

Back in 1969, #Apollo12 flew through some clouds that had weak electrical charge and was struck twice by #lightning, but the mission continued.

In 1987, an Atlas-Centaur rocket and payload were destroyed when its launch triggered lightning.

https://www.nasa.gov/audience/foreducators/9-12/features/F_Lightning_and_Launches_9_12.html

Many of our space launches occur out of Cape Canaveral, #FLwx. Florida averaged 228 total #lightning events per square mile last year per @VaisalaGroup NLDN - so Lightning Launch Commit Criteria ( https://ams.confex.com/ams/pdfpapers/164180.pdf) are important for the space ranges.

I've been in the room with the 45WS prior to a space launch. They're monitoring their #lightning detection network MERLIN ( https://ams.confex.com/ams/97Annual/webprogram/Manuscript/Paper306080/18ARAM-MERLIN%20Overview%20%282017%29.pdf), electric field mills, multiple upper-air launches, radar, and more...

As we get ready to #LaunchAmerica today, the safety of @AstroBehnken and @Astro_Doug are paramount, so if there is a chance that #lightning could negatively impact the flight, there won't be any hesitation to NO GO the launch.

@WHSVaubs @jamesaydelott a little background to lightning launch commit criteria for the space launch today :)