Author Topic: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion Thread 1  (Read 536034 times)

Online Brovane

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #580 on: 12/29/2017 03:00 AM »
Is this just a fit test with payload/fairing attached to verify the TEL and will it be removed before the static fire?

 
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Offline mme

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #581 on: 12/29/2017 05:31 AM »
Is this just a fit test with payload/fairing attached to verify the TEL and will it be removed before the static fire?
I bet they leave it attached. It's not a "real" payload. But I have no inside information.
Space is not Highlander.  There can, and will, be more than one.

Offline docmordrid

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #582 on: 12/29/2017 06:20 AM »
ISTM it gets either a ride to space or a Viking funeral. Either is preferable to an auto parts yard.
« Last Edit: 12/29/2017 06:24 AM by docmordrid »
DM

Offline zhangmdev

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #583 on: 12/29/2017 07:36 AM »
Will this static fire test be different? Longer duration? 20 sec? Or multiple times?
 

Offline topopesto

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #584 on: 12/29/2017 07:57 AM »
I'm very happy for this new news! I like to see the FH on the PAD 39A. The 2018 to start good!

Offline Ben the Space Brit

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #585 on: 12/29/2017 08:45 AM »
It amazes me how difficult it is to scale some of these pictures in my head. I didn't really understand how wide the FH payload fairing is until I saw that a Tesla Roadster can be fit in one horizontally rather than be flipped up so it points along the long axis of the fairing!
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Offline ricmsmith

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #586 on: 12/29/2017 08:59 AM »
Is this just a fit test with payload/fairing attached to verify the TEL and will it be removed before the static fire?

 

I'm almost certain they'll leave it attached, it's not a customer payload - just a mass simulator, it's not a point of failure during the static fire. In fact, fuelling and COPV issues aside, I don't think the static fire itself is going to be at all problematic, certainly not from a catastrophic failure point of view. Things are only really going to get interesting post launch. Can they control 27 engines across 3 cores and keep them balanced? Will there be unanticipated mechanical or (perhaps more likely) aerodynamic loads? Any of those could lead to mission failure.

I don't have any inside line on this, just my personal view.

Offline matt_ellis

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #587 on: 12/29/2017 09:17 AM »
Is this just a fit test with payload/fairing attached to verify the TEL and will it be removed before the static fire?

 

I'm almost certain they'll leave it attached, it's not a customer payload - just a mass simulator, it's not a point of failure during the static fire. In fact, fuelling and COPV issues aside, I don't think the static fire itself is going to be at all problematic, certainly not from a catastrophic failure point of view. Things are only really going to get interesting post launch. Can they control 27 engines across 3 cores and keep them balanced? Will there be unanticipated mechanical or (perhaps more likely) aerodynamic loads? Any of those could lead to mission failure.

I don't have any inside line on this, just my personal view.

I think the static fire test has the potential to be interesting for exactly the same reasons as you list for launch - getting all 27 engines to fire up in a balanced manor without RUD... (e.g. torque stresses ripping the rocket apart, not to mention 3 times the potential failure points of a standard F9) 

No doubt the SpaceX engineers have run numerous simulations and looked at data from the nearly 50(!) previous F9 launches, but I am sure there will be a 'Pucker Factor' on this test as well as the launch.

Offline JamesH65

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #588 on: 12/29/2017 09:21 AM »
Is this just a fit test with payload/fairing attached to verify the TEL and will it be removed before the static fire?

 

I'm almost certain they'll leave it attached, it's not a customer payload - just a mass simulator, it's not a point of failure during the static fire. In fact, fuelling and COPV issues aside, I don't think the static fire itself is going to be at all problematic, certainly not from a catastrophic failure point of view. Things are only really going to get interesting post launch. Can they control 27 engines across 3 cores and keep them balanced? Will there be unanticipated mechanical or (perhaps more likely) aerodynamic loads? Any of those could lead to mission failure.

I don't have any inside line on this, just my personal view.

My view on the multi engine control thing is it's not a problem. They already control 9 engines very successfully. There are of course some added complications (The three cores need to be synchronised to know what each is doing in order to compensate for things going on) , but they have had a long time to work through the control software and should have it pretty much good enough by now! As for aero loads, again, they have had years to work this out in CFD sims, which of course are not perfect, but pretty damn good.

Offline Ben the Space Brit

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #589 on: 12/29/2017 10:12 AM »
Is this just a fit test with payload/fairing attached to verify the TEL and will it be removed before the static fire?

The only reason to remove the payload before the static fire is to protect the customer's payload from any possible catastrophic failure during the test. That isn't a consideration for this flight.
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Online StuffOfInterest

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #590 on: 12/29/2017 10:15 AM »
Seeing all of the photos of the FH vertical left me with two questions, one that can be answered if someone has better eyes than me and one that probably can't be answered yet.

First, can anyone tell if the TE is providing support to the top of the side boosters or are they only supported by the attachment to the center core?  The pictures of the back side of the rocket are not very clear and although it looks like there may be something back there I can't tell for sure.

Second, I know the top support will fold forward to get out of the way of the grid fins.  Any speculation on if that support will fold while the center core is under thrust or if they will wait until staging to fold it?  When the side boosters go I presume the rocket will be above enough of the atmosphere that there won't be any significant aerodynamic load on the support so it may just make sense to let it stay out there until first stage thrust shuts off.  Less power in the retraction piston required.

Offline Johnnyhinbos

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #591 on: 12/29/2017 10:53 AM »
My guess is theyíll remove the payload prior to static fire. Why? Because thatís now SOP for their customersí payloads. So they will want to try to replicate that process as accurately as possible. Additionally, demating and mating a payload to a FH stack would be good practice as Iím sure there are subtle differences to the same operation for F9.

Regardless, weíll know soon enough. Which is amazing!
John Hanzl. Author, action / adventure www.johnhanzl.com

Online Chris Bergin

Yeah, I'm really not sure. Standard is to remove the payload, but yes it's not some expensive satellite....and they may want some three core ignition data on how the entire stack behaves.

I've seen notes claiming both scenarios, so I don't know for sure.

More people heading down to KSC today, so let's keep an eye on the rocket, in case they lower her off the pad, so we can at least warn people on a several hour car trip.

Online deruch

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #593 on: 12/29/2017 12:07 PM »
Yeah, I'm really not sure. Standard is to remove the payload, but yes it's not some expensive satellite....and they may want some three core ignition data on how the entire stack behaves.

I've seen notes claiming both scenarios, so I don't know for sure.

More people heading down to KSC today, so let's keep an eye on the rocket, in case they lower her off the pad, so we can at least warn people on a several hour car trip.

I really wish SpaceX (or somebody else who had cameras in the vicinity) would livestream the first Falcon Heavy SF, like what happened for the first Falcon 9.  Even with zero commentary, discussion, talking, etc.  That would definitely be lit.  [sorry, couldn't help myself there]

http://forum.nasaspaceflight.com/index.php?topic=20787.0
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Online envy887

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #594 on: 12/29/2017 12:13 PM »
My guess is theyíll remove the payload prior to static fire. Why? Because thatís now SOP for their customersí payloads. So they will want to try to replicate that process as accurately as possible. Additionally, demating and mating a payload to a FH stack would be good practice as Iím sure there are subtle differences to the same operation for F9.

Regardless, weíll know soon enough. Which is amazing!

SOP is to fire first, then mate the payload. They don't demate during a nominal flow.

Online Chris Bergin

Yeah, I'm really not sure. Standard is to remove the payload, but yes it's not some expensive satellite....and they may want some three core ignition data on how the entire stack behaves.

I've seen notes claiming both scenarios, so I don't know for sure.

More people heading down to KSC today, so let's keep an eye on the rocket, in case they lower her off the pad, so we can at least warn people on a several hour car trip.

I really wish SpaceX (or somebody else who had cameras in the vicinity) would livestream the first Falcon Heavy SF, like what happened for the first Falcon 9.  Even with zero commentary, discussion, talking, etc.  That would definitely be lit.  [sorry, couldn't help myself there]


http://forum.nasaspaceflight.com/index.php?topic=20787.0


Good call. I'll ask them as they absolutely have all the cameras for it.
« Last Edit: 12/29/2017 12:33 PM by Chris Bergin »

Online FutureSpaceTourist

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #596 on: 12/29/2017 01:24 PM »
Quote
A quick check of the coast reveals no #FalconHeavy on pad. Although up in the late night hours, it appears to possibly be back in the barn. Is it all good or adjustments needed? Nobody knows yet. @SpaceX

https://twitter.com/julia_bergeron/status/946737095565107204

So FH spent less than a day at the pad doing fit checks.

Is that what people expected? Good news, or not?! I donít know what the procedures would be for something like this. Assuming there were some snags to fix, would they try and do that with FH at the pad or would it go back to the HIF first?

Offline Ben the Space Brit

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #597 on: 12/29/2017 01:27 PM »
I imagine that there will be more appearances of the vehicle at the pad. After all, they have to complete the launch campaign for Zuma before SpaceX's East Range team doing any serious work with the FH demonstration flight. I imagine, for now, they're going through connection tests and taking the opportunity of having an FH assembled to make sure the umbilicals and command and control data lines all work properly for a three-core stack.
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Online dnavas

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #598 on: 12/29/2017 01:53 PM »
I think the static fire test has the potential to be interesting for exactly the same reasons as you list for launch - getting all 27 engines to fire up in a balanced manor without RUD... (e.g. torque stresses ripping the rocket apart, not to mention 3 times the potential failure points of a standard F9)

I think it also wise to remember that all companies have an operating philosophy, and that when operation falls outside of well-practiced norms, bad things can happen.  SpaceX is more of a design, test, and fix company than is standard in the industry (at least, from what I've seen), and that suits them because it allows them to try things other companies won't.  Other companies have designed rockets with higher "throw weight to orbit" [dodging 'payload'] where two human beings were going to be part of that "throw weight" on first launch -- that requires a different operating philosophy.  I don't want to be distracted by better or worse, it's just different.  The real problem for SpaceX is that there hasn't been a test of all 27 going off outside of sims, and sims don't tend to model random corrosion problems in nuts (for example).  What is it that they've missed?  Untested is always dangerous.

I'm short, and a little past middle-aged, but I'm not that short or that old (or that wise), and I don't run around forests fronting my direct objects, so I'll try not to act as if I am, but ...  But, if I had to lay down odds for full mission success, they would not be extraordinarily high.  Their first stage landings, which are amazing, were "hard fought".  And two of the first three Falcon 1 launches had problems with stage recontact.  The entire launch regime has "new" written all over it.  Because, hey, while we're at it, why not just go interplanetary....  I'm sure that SpaceX believes there is a reasonable chance of success here, but there's also a reason why they're not launching a "pay"load.

I really, really want to see a success here.  I'm going to be completely distracted from work until launch.  As an engineer, I'll worry about what's being forgotten or overlooked even if I will be concocting plans for building a moon colony and launching a Stanford Torus in my head.  I really hope a successful launch proves every fear I have wrong.  But it seems to me that an ounce of humility goes a long way until then.  The thing I know is, whether the first rocket fails or succeeds, there will be one that works.  Whatever bad thing happens, that thing will get fixed.  Because that's what SpaceX does.

["The cave.  Remember your failure at the cave!"  Urk .. Damn.]

Offline Johnnyhinbos

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #599 on: 12/29/2017 02:06 PM »
Personally I give this mission high probably of success. This is not the SpaceX of Falcon 1, nor is it the SpaceX of the first landing attempts, or of the rammed 2nd stage, or of the LOX curfuffle last year.

This is the SpaceX of now - a SpaceX that has solved booster return, stage separation, densified props, fairing separation, TEL protection, precision RADAR distance measurement, engine relights, ... (I can go on, but you get the idea).

SpaceX has fought hard to learn hard lessons - and these lessons are directly applicable to the FH.

And as a side note - itís also the same reason I marvel when people place New Glenn in the mix as if itís a done deal. BO has a huge and daunting task ahead of itself before the have a dependable orbital class launcher. Iím sure theyíll succeed, but SpaceX has already put many of these lessons behind them and will keep pushing forward while BO has still to learn those same lessons...
John Hanzl. Author, action / adventure www.johnhanzl.com

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