SpaceX F9 : Starlink v0.9 : May 23, 2019 - DISCUSSION

[eeergo]

Elon is surely using short tons in his statement.  First, that's the convention - if he meant metric tonnes, he'd use that.  This can be ambiguous in speech, but this was written.  Just ask google  "18.5 tons in tonnes" to get 16.8 tonnes....

...That's not accurate. "Tons" is correctly and regularly used to mean metric units as well. Musk prefers metric.

So I acknowledge the units are more ambiguous here than we'd like, but I do believe he intended metric tons.

Tonne = Mg = 1000 kg
Ton = US (short) ton ≈ 907.185 kg (≠UK (long) ton ≈ 1016 kg)

[Elthiryel]

Later he sent a tweet himself.

https://twitter.com/elonmusk/status/1128834111878193155

[DaveGee66]

Later he sent a tweet himself.

https://twitter.com/elonmusk/status/1128834111878193155

Thanks - removed my post since it wasn't accurate.

[birdman]

So far SFN is the only source saying this and doesn't give any reason, just that the clocks are stopped... at T-2.5hrs I would wait until someone else confirms before assuming scrubbed.

[John Alan]

So far SFN is the only source saying this and doesn't give any reason, just that the clocks are stopped... at T-2.5hrs I would wait until someone else confirms before assuming scrubbed.

Agreed no other source has spoke up that I can find a the moment...
Winds aloft are "sporty" but have been failing all day...
My guess... they now plan to go later in the 90 minute window... and stopped the clock while they watch and decide.
IMHO... 

On edit... NEVERMIND.... (see update thread).... 

[Bubbinski]

So they scrubbed due to software issues, planning a software update and to try again in about a week. I have to wonder what would have happened last night if the upper level winds were within limits and they had launched. Or would the software issue have manifested itself before T-0?

[jjyach]

More likely they found a very remote chance of something happening in software that could have caused a problem.  Probably did one last dry run today, and decided they needed more safeguards.  By far not the first system to need an update on the pad.

[cppetrie]

I took that to mean satellite software update or deployment software on stage 2. Don’t think that would have impacted launch just deployment. Perhaps something to do with the unfolding of the cards timing

[DavidH]

I'm extremely excited to see this deployment. I hope there a several cameras to watch the spinning platter / spread card deck of satellite deployments. I'm surprised no one has built a simulation video of the card deck dispenser method.

Call this a request. I could imagine several techniques to satisfy the description of the card deck but my video skills are severly lacking to attempt such a sim.

[king1999]

I took that to mean satellite software update or deployment software on stage 2. Don’t think that would have impacted launch just deployment. Perhaps something to do with the unfolding of the cards timing

The tweet only mentioned satellite software.

[CyndyC]

'Spreading cards on a table' brought up multiple YouTube videos. The ones I browsed all stressed the application of the index finger alone, and application with decreasing pressure. So at satellite deployment presumably there will be a virtual index finger, the decreasing acceleration proportionate to the distance from the rotating core, unless the deployment is in vacuum. Does that sound about right so far? Below is one of the more compact videos

[kdhilliard]

GO Searcher and GO Navigator arrived at Port Canaveral just after dawn, at 6am EDT this morning.
Of Course I Still Love You is estimated to arrive at 9pm EDT tonight.

...

Interesting that they came all the way home instead of just pulling in to some place closer -- perhaps Wilmington, up the Cape Fear River.

[marsbase]

GO Searcher and GO Navigator arrived at Port Canaveral just after dawn, at 6am EDT this morning.
Of Course I Still Love You is estimated to arrive at 9pm EDT tonight.

...

Interesting that they came all the way home instead of just pulling in to some place closer -- perhaps Wilmington, up the Cape Fear River.

Crews probably have families in the Cape Canaveral area.

[Shanuson]

GO Searcher and GO Navigator arrived at Port Canaveral just after dawn, at 6am EDT this morning.
Of Course I Still Love You is estimated to arrive at 9pm EDT tonight.

...

Interesting that they came all the way home instead of just pulling in to some place closer -- perhaps Wilmington, up the Cape Fear River.

Crews probably have families in the Cape Canaveral area.

Where they would have been faster if the went to a closer port and took a car or flight.

To me this sound like they need to resupply or the expected delay is much more than 1 week and they can work on something on these ships now instead of just waiting.
Or they can't use a different port from some reason (legal? fees?) but they where using a different port (Jacksonville) for the first few drone ship missions.

[kdhilliard]

Now targeting May 23 for launch of Starlink from Pad 40 in Florida

I assume this is May 23, 22:30 Eastern => May 24, 02:30 UTC.

OCISLY departed Port Canaveral four days prior to the first launch attempt.  (May 11 21:00 EDT departure to support the May 15 22:30 attempt.)  Arriving back home this morning at dawn, they won't have much time to take care of everything before getting underway again to support Thursdays launch attempt, just three days from tonight.

Edit: OCISLY departed late afternoon, after only 12 hours in port.

[.Scott]

Responding to @envy887 (reply #299):

Angle of Attack (AoA) applies to a lifting surface - of which the Falcon, during liftoff configuration, has none.
If you want to say that it is a function of the air mass velocity and the aircraft velocity, then you also need to include the air craft pitch and other dynamics as well.
AoA is the angle between the wing chord and the relative wind across the surfaces of the wing.  In extreme maneuvers (spins and snap rolls), it can be vastly different from one wing to the other.

[drzerg]

Responding to @envy887 (reply #299):

Angle of Attack (AoA) applies to a lifting surface - of which the Falcon, during liftoff configuration, has none.
If you want to say that it is a function of the air mass velocity and the aircraft velocity, then you also need to include the air craft pitch and other dynamics as well.
AoA is the angle between the wing chord and the relative wind across the surfaces of the wing.  In extreme maneuvers (spins and snap rolls), it can be vastly different from one wing to the other.

this is not correct. because if so falcon will be flying vertically in space. and do not forget about wind change in different altitudes.

anything exept maybe a sphere will produce lift if fast enough.

[acsawdey]

Responding to @envy887 (reply #299):

Angle of Attack (AoA) applies to a lifting surface - of which the Falcon, during liftoff configuration, has none.
If you want to say that it is a function of the air mass velocity and the aircraft velocity, then you also need to include the air craft pitch and other dynamics as well.
AoA is the angle between the wing chord and the relative wind across the surfaces of the wing.  In extreme maneuvers (spins and snap rolls), it can be vastly different from one wing to the other.

No. Here's an old NACA report from 1951. Figure 11 gives coefficient of drag and lift vs angle of a attack for a rather rocket-shaped body at mach 3.85. It's pointier than a F9 with fairing, but I think you can see that it doesn't have to be a wing to have an angle of attack and lift.

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930086899.pdf

Bringing this back on topic, a sudden change in wind velocity means a sudden change in angle of attack and lifting forces acting on the rocket.

[Nomadd]

Responding to @envy887 (reply #299):

Angle of Attack (AoA) applies to a lifting surface - of which the Falcon, during liftoff configuration, has none.
If you want to say that it is a function of the air mass velocity and the aircraft velocity, then you also need to include the air craft pitch and other dynamics as well.
AoA is the angle between the wing chord and the relative wind across the surfaces of the wing.  In extreme maneuvers (spins and snap rolls), it can be vastly different from one wing to the other.

this is not correct. because if so falcon will be flying vertically in space. and do not forget about wind change in different altitudes.

anything exept maybe a sphere will produce lift if fast enough.

Actually, a sphere can have lift if it's spinning.

[billh]

Actually, a sphere can have lift if it's spinning.

You're just trying to throw us a curve...