I get that you dont want to fly a giant rocket full of liquid oxygen and other explosives into a thunderstorm or hurricane, but what are some practical reasons for postponing a launch due to weather. As I (hardly) understand once you get high up in the atmosphere there is high wind even on a clear day, does rain matter that much?
First of all, weather is much more than just rain.
One of the things that's monitored closely in the launch corridor are the upper atmospheric winds. Specifically the wind sheer in the upper atmosphere. Strong wind isn't typically a problem, but high wind sheer in the upper atmosphere can be problematic.
Additionally, they check the weather in the entire recovery corridor. That is, anywhere that the capsule could end up during an abort. They want to make sure that if the capsule ends up in the ocean, the weather permits recovery operations. An abort and safe splash-down doesn't do us much good if the astronauts then drown because recovery operations are impaired due to weather.
We're putting two lives on this rocket. A small delay is absolutely the right trade-off to reduce risk.
Recovery due to an in-flight abort would be difficult in rough seas and weather if they had to be plucked out of the Atlantic.
The aerostructure of the falcon 9 can only withstand so much side loading due to aerodynamic forces and wind before exceeding the operational limits of the rocket (body to keep it all from breaking apart, and the engines working hard to keep them on the correct trajectory).
Thank you for the answer. To those who downvoted- I normally don't comment on that, but damn it was an honest question and I admitted to having little knowledge on this and its not like I gave a hot take. Just wanting to learn something...
The issue isn't so much high wind but wind shear. Namely when you pass through a sharp change in air direction there's a bending force applied to the rocket that's proportional to the vehicle speed and atmospheric density. This can get very high and risk destroying the rocket.
On this note, does anybody know what the weather thresholds are that would cancel the launch? I mean, the current forecast suggests it will almost definitely be raining at 433pm Eastern, and wind will be around 10 mph. Is some amount of rain tolerable? How much wind is acceptable?
Nominally a 60% chance of a go for launch weather, but according to Ken the Bin on Ars Technica, the weather in the abort corridor is poor so he expects a postponement.
I live on Merritt Island. Our power has been out since 6:30 this morning due to intense storms in the area. That having been said, it is currently sunny and calm.
Given what the weather has been like since Sunday I could see it being postponed. I hope the weather holds and gives a window.
Typically that percent chance doesn't actually consider all the launch criteria as crazy as that sounds.
It misses the upper level winds, and for the human launch I wouldn't be at all surprised to find out that it is missing some weather criteria in the abort recovery zone as well.
