SpaceX FH : Falcon Heavy Demo : Feb 6, 2018 : Discussion Thread 2

[Lar]

Time to recondition a possible issue?

https://twitter.com/S101_Live/status/960945681224622080

One item the Launch Team will evaluate is whether there is enough of a favorable trend in the winds to justify loading the vehicle. There may not be enough time to re-condition over 900 metric tons of LOX between the end of today's & the opening of tomorrow's window. #FalconHeavy

[Danrar]

The scrub turn around after fueling would probably depend on how much LOX is tanked. The larger amount of LOX needed than you'd find on a single stick would mean you'd need to scrub before you use more LOX than you can produce in the next 20 hours or so.

The question is how much time would this buy them if they decided to start.

[mheney]

Question on behalf of young newbies (just shy of 40) like myself.

Were space launches always this finicky when it comes to wind and other mild weather phenomena, even in the mighty Apollo days?

Well, Apollo 12 launched through a thunderstorm.  That got a bit exciting.  They changed a lot of the launch rules after that.

Shuttle was finicky with weather.  But looking at the aerodynamics of that stack, it's understandable.

With this launch, you're flying a brand new configuration.  You don't want to push the envelope unnecessarily.  When you have flight data rather than model data on the 3-core configuration, you can tweak your launch parameters, but "better safe than sorry" is a sign of wisdom at this point.  You want to maximize your chances for success.

[the_other_Doug]

Shuttle days, for sure.  Apollo... well, look at the infamous Apollo 12 lightning strikes.

Yeah, well -- they figured that nothing short of a hurricane could stop a Saturn V.  And they did have launch rules that they would not launch when there was lightning observed within 5 miles of the pad.  They just didn't foresee the grounding effect of the Saturn's ionized exhaust.

As for high-level winds, I can recall in Apollo days some discussion of them, but never a launch scrub because of high-altitude wind shear.  And correct me if I'm wrong, but the larger or longer the vehicle, the more impact from upper-level wind shear, right?  So, I don't think the Saturn just powered through them because it was so big and powerful -- they would have torn apart a Saturn stack more easily than a smaller vehicle, IIRC.

Shuttles got delayed due to high-level winds many times, though.  Maybe Apollo just got lucky...

[Joffan]

Shuttle days, for sure.  Apollo... well, look at the infamous Apollo 12 lightning strikes.

SCE to AUX!

Saturn V was a battleship of a rocket, though. Perhaps a reasonable cost of space access precludes the ability to survive lightning strikes.

[Greg Hullender]

Question on behalf of young newbies (just shy of 40) like myself.

Were space launches always this finicky when it comes to wind and other mild weather phenomena, even in the mighty Apollo days?

Yeah. I watched lots of launches in school, back to maybe a Ranger launch in first grade. (Imagine the national mindset in 1964 if they stopped class for an hour to let first-graders watch the launch of an unmanned probe.) Every kid in America learned how to count down as easily as up, and the worst words you could hear (always getting a groan from the whole class) were "there's a hold."

I don't remember so many scrubs, though. Perhaps they had large launch windows since they were always going to low Earth orbit (even Apollo, since they had to hook up with the LEM and get situated before heading to the moon.)

[Jim]

Time to recondition a possible issue?

https://twitter.com/S101_Live/status/960945681224622080

One item the Launch Team will evaluate is whether there is enough of a favorable trend in the winds to justify loading the vehicle. There may not be enough time to re-condition over 900 metric tons of LOX between the end of today's & the opening of tomorrow's window. #FalconHeavy

If they haven't tanked and so there should be no need to re-condition LOX

[docmordrid]

@elonmusk
Launch auto-sequence initiated (aka the holy mouse-click) for 3:45 liftoff #FalconHeavy

https://twitter.com/elonmusk/status/960949244982018049

[the_other_Doug]

Shuttle days, for sure.  Apollo... well, look at the infamous Apollo 12 lightning strikes.

SCE to AUX!

Saturn V was a battleship of a rocket, though. Perhaps a reasonable cost of space access precludes the ability to survive lightning strikes.

They got lucky that Apollo 12 survived the lightning discharges.  The circuits that were directly exposed to the full strength of the discharges was literally fried.  It was very fortunate that this only included some external sensors and some RCS gauge sensors.  The problems they did have were caused by induced currents.

I have always been struck by the wording used in the book "Apollo" describing Skip Chauvin's thoughts of the time -- that he wasn't worried about rain; short of torrential downpours, the Saturn V wasn't affected by rain.

I bet the FH, as well as most of the other of today's vehicles, care about rain more than the Saturn V did...

[bdub217]

Remember that shuttle already had to deal with considerable launch weather constraints not just for launch, but also for an RTLS and TAL contingency abort. For the RTLS weather, they had to be pretty sure the winds would be remain acceptable through the abort window (20 - 30 minutes?) after launch.

Wayne Hale wrote a blog entry once describing how he nearly got fired by a military retread for scrubbing a launch on a beautiful sunny day in Florida due to TAL weather.

[Lar]

Time to recondition a possible issue?

https://twitter.com/S101_Live/status/960945681224622080

One item the Launch Team will evaluate is whether there is enough of a favorable trend in the winds to justify loading the vehicle. There may not be enough time to re-condition over 900 metric tons of LOX between the end of today's & the opening of tomorrow's window. #FalconHeavy

If they haven't tanked and so there should be no need to re-condition LOX

Yes, but that's not what this concern has to do with .... IF they start tanking (starts at T-45) then it is (possibly) a concern. With the current launch time of 3:45, they have to start tanking in about 1 hour... Agree that if they scrub before that it's not.

[Flying Beaver]

.... IF they start tanking (starts at T-45) then it is (possibly) a concern. With the current launch time of 3:45, they have to start tanking in about 1 hour... Agree that if they scrub before that it's not.

They precondition the RP-1 as well.

There must be a % of tanking where re-conditioning would take sub-24hrs to perform, Anything more and it's a 48hr recycle. So not a cutoff at the start of prop load.

[ZachS09]

How are the upper level winds looking now?

Are they still above the limits or have they calmed down?

[Danrar]

How are the upper level winds looking now?

Are they still above the limits or have they calmed down?

If they started the sequence then they like what they see.

[Mike_1179]

How are the upper level winds looking now?

Are they still above the limits or have they calmed down?

They said currently no constraints to launch, so no data to indicate winds are a problem NOW. As for winds at 15:45, they will likely have to wait for balloon data

[Nascent Ascent]

Has there been any info on whether the Tesla is equipped with cameras?  Any chance of images of the car in space?

[alexterrell]

Question on behalf of young newbies (just shy of 40) like myself.

Were space launches always this finicky when it comes to wind and other mild weather phenomena, even in the mighty Apollo days?

Yeah. I watched lots of launches in school, back to maybe a Ranger launch in first grade. (Imagine the national mindset in 1964 if they stopped class for an hour to let first-graders watch the launch of an unmanned probe.) Every kid in America learned how to count down as easily as up, and the worst words you could hear (always getting a groan from the whole class) were "there's a hold."

I don't remember so many scrubs, though. Perhaps they had large launch windows since they were always going to low Earth orbit (even Apollo, since they had to hook up with the LEM and get situated before heading to the moon.)

Another question: Is this being shown on main stream TV anywhere? Was Apollo shown live on mainstream TV?

I know the BBC is busy showing some minor football, but it seems no one wants to broadcast this live. OK - there are now webcasts, and I'm sure the news will have a report on it, but it's not got the interest the first space shuttle had. Or is that unrealistic? Do we compare it to the first Delta IV or the first Arianne?

[Semmel]

GO FOR PROP LOAD!!!!!!

whoooo! hope my little one sleeps through the next 2 hours. Would break my heart to leave him cry to watch this launch [1]. And I still dont understand why the launch radio is not streamed publicly. The poll is the best part of a launch, pre-launch.

Fingers crossed!

[1]: Obviously, I would do the opposite and watch a reply instead of letting him cry.

[sevenperforce]

Has there been any info on whether the Tesla is equipped with cameras?  Any chance of images of the car in space?

I spotted at least three cameras showing the Tesla on Elon's tweet.

[mlindner]

Another question: Is this being shown on main stream TV anywhere? Was Apollo shown live on mainstream TV?

I know the BBC is busy showing some minor football, but it seems no one wants to broadcast this live. OK - there are now webcasts, and I'm sure the news will have a report on it, but it's not got the interest the first space shuttle had. Or is that unrealistic? Do we compare it to the first Delta IV or the first Arianne?

Apollo was the most viewed thing on TV to ever be shown at that time. Estimated that a billion people watched it live.