Maximum upper-level winds will be from the west at 105 knots at 40,000 feet.On Wednesday, skies will begin to clear [...]. Maximum upper-level winds will be from the west at 130 knots near 40,000 feet.
From the launch forecast issued yesterday:QuoteMaximum upper-level winds will be from the west at 105 knots at 40,000 feet.On Wednesday, skies will begin to clear [...]. Maximum upper-level winds will be from the west at 130 knots near 40,000 feet.I know wind shear is a particular concern but is there also an upper limit on wind speed F9 can tolerate?
Are this micro and nanosatellites onboard of CRS-13 ?Violet 50 USA Cornell UniversityQBUS 3 2 USA Stanford UniversityLAICE 12 USA University Of IllinoisHARP 3 USA University Of MarylandOPAL 3 USA Space Dynamic LaboratoryOPEN 1 USA University Of North DakotaCPOD 1 3 USA Tyvak Nanosatellite CenterCPOD 2 3 USA Tyvak Nanosatellite CenterRANGE A 2 USA Georgia Institute Of TechnologyRANGE B 2 USA Georgia Institute Of Technology
Just as a remark: Violet has been cancelled and won't fly.
Upper levels winds are constraint base.
Sorry, I'm not familiar with the terminology, what does the following mean in the context of being able to launch or not:Quote from: ChrisGebhardt on 12/11/2017 03:24 pmUpper levels winds are constraint base.
Working with NASA since Jan. Equivalent risk established. All groups meeting for several months. 2 weeks before launch was when the decision had to be made.NASA went off on their own to come up with what they wanted to see for Falcon 9 reuse. NASA put on constraints. Only single reflight agreed to. Only a CRS-like mission is where that booster could come from. Decision was made so finely. Re-flgiht Readiness Review (RFRR). NASA was so late making decision because RFRR came in so only allow official decision.New booster could have effected the launch date.
From Updates thread: Quote from: ChrisGebhardt on 12/11/2017 03:31 pmWorking with NASA since Jan. Equivalent risk established. All groups meeting for several months. 2 weeks before launch was when the decision had to be made.NASA went off on their own to come up with what they wanted to see for Falcon 9 reuse. NASA put on constraints. Only single reflight agreed to. Only a CRS-like mission is where that booster could come from. Decision was made so finely. Re-flgiht Readiness Review (RFRR). NASA was so late making decision because RFRR came in so only allow official decision.New booster could have effected the launch date.If they can only reuse "CRS-like" boosters (presuming that means lightweight LEO mission, low reentry stresses on booster, probably LZ-1 only landings) with a single prior flight for CRS missions, then they don't have too many choices.CRS-8 was already reused, and CRS-9's core is spoken for. They are using the CRS-11 booster. The boosters for CRS-10 and 12 are available, as far as I know, and presumably the booster for the NROL-76 mission, and possibly the X-37B mission as well.
So... #SpaceX launch weather discussion time. Ground winds are the ONLY thing including in the 90% go prediction for tomorrow. BUT... upper levels winds need to be watched too - though they're not including in the official weather prediction. @NASASpaceflight 1/x
They're not included because the 45th weather squadron is not responsible for making a call on Upper Level wind acceptability for launch. That decision falls to SpaceX. @NASASpaceflight 2/x
So tomorrow, the 45th will monitor & report Upper Level Wind (ULW) speed and direction to SpaceX. SpaceX will then make the call on whether the ULWs are within acceptable limits for launch to proceed. @NASASpaceflight 3/3
Interesting... Why would SpaceX not release ULW limits to the 45th?
It's a moving target constraint depending on launch trajectory, payload, weight, vehicle performance, altitude of winds, direction of winds, speed of winds. Easier for 45th to just report what Upper Level Winds are to SpaceX & let them figure out if the winds are within limits.
Is it known or proprietary what upper level wind speeds would be a no-go call? educated guess? 100+knots?
SpaceX has never stated publicly what the Upper Level Wind speed/direction limits are for Falcon 9. And the wind speed limit is different based on direction of wind.
As far as the upper wind thing, its most likely not an absolute number, but rather the GRADIENT that's the problem.F9 has a lateral acceleration limit. Turbulence and wind shear causes this.If the wind smoothly accelerates from 0 to 200knots (over 40000ft), there would likely be no problem for F9.In the real world it doesn't work like that. There are sudden changes in wind.Its a bit complicated to translate into a simple upper wind speed limit number.And I wouldn't be surprised if SpaceX is fudging what they expect will be the ultimate safety limit vs a more conservative number they keep slowly stretching.SpaceX knows what its doing. Let them do it.
AIUI there is wind shear and just plain wind, they both have [different] limits (and certainly those limits are not fixed numbers, but rather depend on lots of details).
