Author Topic: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION  (Read 864599 times)

Offline WHAP

  • Member
  • Full Member
  • ****
  • Posts: 795
  • Liked: 104
  • Likes Given: 8
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1600 on: 03/02/2016 05:07 AM »
I'm struggling to understand the logic that says a multiple day delay is worth it for such a low probability of success for booster recovery.  Unless that isn't what's driving the decision here.

It has nothing to do with booster recovery. It has everything to do with not breaking the vehicle as it flies through high wind shear. Upper level winds are forecast to be too high for the vehicle structure to handle until Friday. And they must have enough confidence in the forecast not to want to waste time and effort on an earlier attempt that would likely scrub.

I never suggested that SpaceX should launch if the conditions exceeded the capability of the vehicle.  I questioned SpaceX's rationale for not making an attempt.

Subsequent posts provided supporting evidence for my argument.  The examples given were vehicles that tried to launch on a given day - including Falcon 9.  They didn't use forecasts, they used actual data on launch day to determine if they could meet their criteria.
We'll see if Friday if the forecasts were right.  You seem quite convinced they will not be.  Since I am not a meteorologist, I will defer to those who are.

Another misinterpretation.  I did not suggest that the upper level winds would not subside by Friday.  I questioned SpaceX's rationale for not making an attempt before then.  Unless someone releases balloons Wednesday and Thursday, we'll never know.
ULA employee.  My opinions do not necessarily reflect those of my employer.

Offline deruch

  • Senior Member
  • *****
  • Posts: 2250
  • California
  • Liked: 1753
  • Likes Given: 3779
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1601 on: 03/02/2016 05:41 AM »
I'm struggling to understand the logic that says a multiple day delay is worth it for such a low probability of success for booster recovery.  Unless that isn't what's driving the decision here.

It has nothing to do with booster recovery. It has everything to do with not breaking the vehicle as it flies through high wind shear. Upper level winds are forecast to be too high for the vehicle structure to handle until Friday. And they must have enough confidence in the forecast not to want to waste time and effort on an earlier attempt that would likely scrub.

I never suggested that SpaceX should launch if the conditions exceeded the capability of the vehicle.  I questioned SpaceX's rationale for not making an attempt.

Subsequent posts provided supporting evidence for my argument.  The examples given were vehicles that tried to launch on a given day - including Falcon 9.  They didn't use forecasts, they used actual data on launch day to determine if they could meet their criteria. (emphasis added)
But that potentially mis-characterizes the sequence of events.  How far in advance can accurate "high level winds and shear" projections really be made?  When the LV Co. & range set launch target/NET dates far in advance, it may not be worth it to delay the launch attempt based on more recent forecasting.  Especially if there's a chance that the vehicle can "find a path" through the shear to orbit.  But given the fact that SpaceX was already resetting the NET date due to the scrubs and that they had good up-to-date projections (assumption), it might make sense to forgo an otherwise available day.  Of course this depends on their confidence in the modeling, etc.
Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

Offline Lee Jay

  • Elite Veteran
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 6669
  • Liked: 973
  • Likes Given: 139
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1602 on: 03/02/2016 05:47 AM »
I'm struggling to understand the logic that says a multiple day delay is worth it for such a low probability of success for booster recovery.  Unless that isn't what's driving the decision here.

It has nothing to do with booster recovery. It has everything to do with not breaking the vehicle as it flies through high wind shear. Upper level winds are forecast to be too high for the vehicle structure to handle until Friday. And they must have enough confidence in the forecast not to want to waste time and effort on an earlier attempt that would likely scrub.

I never suggested that SpaceX should launch if the conditions exceeded the capability of the vehicle.  I questioned SpaceX's rationale for not making an attempt.

Subsequent posts provided supporting evidence for my argument.  The examples given were vehicles that tried to launch on a given day - including Falcon 9.  They didn't use forecasts, they used actual data on launch day to determine if they could meet their criteria.
We'll see if Friday if the forecasts were right.  You seem quite convinced they will not be.  Since I am not a meteorologist, I will defer to those who are.

Another misinterpretation.  I did not suggest that the upper level winds would not subside by Friday.  I questioned SpaceX's rationale for not making an attempt before then.  Unless someone releases balloons Wednesday and Thursday, we'll never know.

Maybe they have other things they want to accomplish between now and the next attempt, such as equipment maintenance or repair or the resting of their personnel.

Offline LastStarFighter

  • Full Member
  • **
  • Posts: 231
  • Europa
  • Liked: 71
  • Likes Given: 11
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1603 on: 03/02/2016 06:11 AM »
I'm struggling to understand the logic that says a multiple day delay is worth it for such a low probability of success for booster recovery.  Unless that isn't what's driving the decision here.

It has nothing to do with booster recovery. It has everything to do with not breaking the vehicle as it flies through high wind shear. Upper level winds are forecast to be too high for the vehicle structure to handle until Friday. And they must have enough confidence in the forecast not to want to waste time and effort on an earlier attempt that would likely scrub.

I never suggested that SpaceX should launch if the conditions exceeded the capability of the vehicle.  I questioned SpaceX's rationale for not making an attempt.

Subsequent posts provided supporting evidence for my argument.  The examples given were vehicles that tried to launch on a given day - including Falcon 9.  They didn't use forecasts, they used actual data on launch day to determine if they could meet their criteria.
We'll see if Friday if the forecasts were right.  You seem quite convinced they will not be.  Since I am not a meteorologist, I will defer to those who are.

Another misinterpretation.  I did not suggest that the upper level winds would not subside by Friday.  I questioned SpaceX's rationale for not making an attempt before then.  Unless someone releases balloons Wednesday and Thursday, we'll never know.

I agree. Seems odd to not at least attempt. Scrub the launch 8 hours before if that balloon looks bad but seems odd not to try on Thursday.

Online woods170

  • IRAS fan
  • Senior Member
  • *****
  • Posts: 8240
  • IRAS fan
  • The Netherlands
  • Liked: 4417
  • Likes Given: 1382
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1604 on: 03/02/2016 06:55 AM »
I agree. Seems odd to not at least attempt. Scrub the launch 8 hours before if that balloon looks bad but seems odd not to try on Thursday.
It only seems odd to you because SpaceX works with professional meteorologists, and you don't.

Offline Jet Black

SpaceX are doing what they do with the approval of SES and the range. That's what's important here.
For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled. -- Richard Feynman

Offline cuddihy

  • Full Member
  • ****
  • Posts: 831
  • Liked: 152
  • Likes Given: 165
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1606 on: 03/02/2016 11:06 AM »
I agree. Seems odd to not at least attempt. Scrub the launch 8 hours before if that balloon looks bad but seems odd not to try on Thursday.
It only seems odd to you because SpaceX works with professional meteorologists, and you don't.

Exactly. High altitude wind shear 2 days out is one of the weather effects the WeatherGuessers have maximum confidence in as its a big-scale and predictable effect. It's not microclimate stuff.

Offline gospacex

  • Senior Member
  • *****
  • Posts: 3028
  • Liked: 537
  • Likes Given: 604
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1607 on: 03/02/2016 12:41 PM »
I'd put SpaceX's foray into sub-cooled LOX in the same category as the high fineness ratio issue.  Some decisions increase operational cost and aren't worth the effort.

While SpaceX could decide against subcooling, SpaceX could not avoid making the rocket longer when their engines become more powerful.

Even disregarding the need to change factory tooling and GSE to increase stage diameter, this would also make their rockets not road-transportable. How would they get to McGregor then? A complete non-starter.

Offline kenban

  • Member
  • Posts: 12
  • Ohio
  • Liked: 2
  • Likes Given: 0
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1608 on: 03/02/2016 12:42 PM »

I never suggested that SpaceX should launch if the conditions exceeded the capability of the vehicle.  I questioned SpaceX's rationale for not making an attempt.

Subsequent posts provided supporting evidence for my argument.  The examples given were vehicles that tried to launch on a given day - including Falcon 9.  They didn't use forecasts, they used actual data on launch day to determine if they could meet their criteria.

Except what you are asking for is impossible.  SpaceX cannot make a launch attempt every day of the week.  The range has required rest periods.

Offline Lee Jay

  • Elite Veteran
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 6669
  • Liked: 973
  • Likes Given: 139
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1609 on: 03/02/2016 01:04 PM »
Even disregarding the need to change factory tooling and GSE to increase stage diameter, this would also make their rockets not road-transportable. How would they get to McGregor then? A complete non-starter.

How do you figure that?  The first stage is only 41 meters long.  We ship 53m wind turbine blades over the road all the time (literally by the thousands), and their maximum chord length is about the same as the stage 1 diameter.  I drove past one on the way to work just the other day.
« Last Edit: 03/02/2016 01:09 PM by Lee Jay »

Offline edkyle99

  • Expert
  • Senior Member
  • *****
  • Posts: 12735
    • Space Launch Report
  • Liked: 3659
  • Likes Given: 731
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1610 on: 03/02/2016 01:14 PM »
F9v1.1 and FT have a very high fineness ratio.  So this vehicle may be more susceptible to structural wind shear effects compared to others.

Can you explain? I understand fineness when applied to an airplane, but a rocket is... a cylinder, how can the fineness ratio be so different compared to Falcon 9 v 1.0 or to the ULA rocket?
Just means length to diameter ratio. It's long and skinny.
And bendy.  Bending modes are an issue with every rocket, but this one is probably the bendiest.

 - Ed Kyle
« Last Edit: 03/02/2016 03:33 PM by edkyle99 »

Offline Kim Keller

  • Full Member
  • ****
  • Posts: 920
  • Not OldSpace, Not NewSpace - I'm ALLSpace
  • Location: Wherever the rockets are
  • Liked: 2102
  • Likes Given: 112
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1611 on: 03/02/2016 01:50 PM »
SX has pulled F9-22 off the pad.

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8646
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1114
  • Likes Given: 243
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1612 on: 03/02/2016 01:59 PM »
SX has pulled F9-22 off the pad.
How long till someone posts they are using high winds as a cover for a problem with the rocket?
3...2...1.......
If you're happy and you know it,
It's your med's!

Offline CorvusCorax

  • Full Member
  • ****
  • Posts: 425
  • Germany
  • Liked: 448
  • Likes Given: 338
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1613 on: 03/02/2016 02:08 PM »
SX has pulled F9-22 off the pad.
How long till someone posts they are using high winds as a cover for a problem with the rocket?
3...2...1.......

If I were a mod, I would move any self-fulfilling prophecies like that to the party thread - along with any potential answers ;)

Edit: also - as they are obviously using the horizontal integration building to cover the rocket now , it shouldn't be exposed to any winds at all unless someone left the doors open ;)
« Last Edit: 03/02/2016 02:11 PM by CorvusCorax »

Offline JasonAW3

  • Senior Member
  • *****
  • Posts: 2438
  • Claremore, Ok.
  • Liked: 395
  • Likes Given: 11
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1614 on: 03/02/2016 02:15 PM »
SX has pulled F9-22 off the pad.

As tall as that bird is, it's no wonder.  High winds could cause undue stresses on the structure, even with it attached to its' gantry.
My God!  It's full of universes!

Offline Lee Jay

  • Elite Veteran
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 6669
  • Liked: 973
  • Likes Given: 139
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1615 on: 03/02/2016 02:26 PM »
While we wait, I thought I'd share a website I got from a friend.

https://www.windyty.com/

Mess with it a little, especially the bar at the bottom.

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8646
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1114
  • Likes Given: 243
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1616 on: 03/02/2016 02:36 PM »
I thought the wind issue was upper level winds, not ground winds. Still, it makes sense to move the rocket and payload inside. No sense exposing it to the elements. Particularly that horrible Hydrogen and Oxygen combination that is so common in Florida.
If you're happy and you know it,
It's your med's!

Offline llanitedave

  • Senior Member
  • *****
  • Posts: 2145
  • Nevada Desert
  • Liked: 1319
  • Likes Given: 1552
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1617 on: 03/02/2016 02:47 PM »
I agree. Seems odd to not at least attempt. Scrub the launch 8 hours before if that balloon looks bad but seems odd not to try on Thursday.
It only seems odd to you because SpaceX works with professional meteorologists, and you don't.


Setting up the range and GSE personnel for a launch attempt is expensive.  Why expend the resources if there's not a decent chance of getting off the ground?  Who's money are we burning?
"I've just abducted an alien -- now what?"

Offline Kabloona

  • Senior Member
  • *****
  • Posts: 4303
  • Velocitas Eradico
  • Fortress of Solitude
  • Liked: 2532
  • Likes Given: 524
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1618 on: 03/02/2016 02:56 PM »
While we wait, I thought I'd share a website I got from a friend.

https://www.windyty.com/

Mess with it a little, especially the bar at the bottom.

Nice tool, but it doesn't seem able to report wind speeds over 29 m/sec, unfortunately.

I selected the "10km" layer over the Cape and played with the "time" bar at the bottom. But I could not get the windspeed scale to exceed 29 m/sec. And the chart Elon tweeted yesterday showed about 70 m/sec at 10km. Obviously a big difference. So the tool seems to work better at lower altitude where wind speed is less.
« Last Edit: 03/02/2016 03:01 PM by Kabloona »

Offline CorvusCorax

  • Full Member
  • ****
  • Posts: 425
  • Germany
  • Liked: 448
  • Likes Given: 338
Re: SpaceX Falcon 9 FT - SES-9 - March 4, 2016 - DISCUSSION
« Reply #1619 on: 03/02/2016 02:57 PM »
While we wait, I thought I'd share a website I got from a friend.

https://www.windyty.com/

Mess with it a little, especially the bar at the bottom.

That's an awesome tool. Especially since you can both switch through the different altitude levels and the multi day forecast. (and zoom for a global view)

Checking the difference between yesterday and Friday actually shows very little difference in high altitude winds over Florida. The 30k ft jetstream is still blowing full force over the coast, but yesterday and today that's contrasted by very low winds in low and medium altitude.

On Friday there will be much stronger winds in lower altitudes as well - in the same direction. So the sudden "sledgehammer" shift in wind speed and direction should not be as extreme.


Tags: