Author Topic: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion  (Read 431448 times)

Online Lar

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #500 on: 12/23/2017 03:22 PM »
You could have said the same about reusing the shuttle boosters (snip...)

It would be hard to prove now but I beleive I DID say exactly that, way back in the day.
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Offline Lars-J

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #501 on: 12/23/2017 03:42 PM »
Can someone explain why they didn't use the Tangent Ogive shape of the Ariane 5 booster?

Because that would make the booster hard to fly and land on its own. (Imagine trying to land a plane with a tail rudder permanently angled to one side)

Also it that ULA is moving away from booster nose cones like that (the upgraded Atlas V SRBs have plain conical nose cones), so the benefits of them are clearly not significant.

Offline zhangmdev

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #502 on: 12/23/2017 04:22 PM »
I remember someone said an SRB is virtually unsinkable after splashdown, if not retrieved those two giant steel casing floating around could be hazardous to shipping.

Online Space Ghost 1962

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #503 on: 12/23/2017 05:17 PM »
Can someone explain why they didn't use the Tangent Ogive shape of the Ariane 5 booster?
Flight frequency? Need? Development schedule overload? Lifetime of vehicle?

Never really thought that FH has gotten the same amount of attention that F9/BFS/BFR have had.

It started out as "Falcon 9 Heavy" as a simple expedite, in part to launch those Iridium missions like last night. (I wonder if they just had bolted together three F9 1.0's and flown them as if a single expendable booster no separation of boosters, and accept the non optimality to begin.)

Instead, more like BO, they've obsessed with single core performance with enhanced engines, and the FH program has evolved constantly til the point that SLC-4E's TEL, which was intended to fly it, couldn't.

FH has become one of the last steps of the Falcon launch vehicle family, probably done before block 4/5 because you'd want to have the vehicle operational so you can apply the flight history to the reuse improvements for them to both share the FH/F9 economics closely (very much unlike DIVH which was much more problematic).

Possibly if FH has more applicability (like in the case of lunar free return flights?),  the tangent ogive's might be factored in.

As for Ariane, it only flew/flies with the side boosters, so all considerations for the entire vehicle were from the start.

My only theory is for boundary layer/flow separation symmetry and controllabilty for landing (as it then becomes a "boatail" during entry and approach) and maintain known flight control algorithms from Falcon 9 S1.
Nope. What it would do is change the area affected by the larger grid fins, shifting the center line off center.

The vehicles already have to compensate for asymmetries, and on the F9 RTLS they have been using greater angle of attack on the boosters, which provokes a similar asymmetry, which the guidance software deals with as well as things like crosswinds.

They will have off kilter aerodynamics due to the strong asymmetry.
Not really.

Just shifts CP going up, shifts "ineffectual" area coming down (you could lengthen the fins still more to compensate if you needed even more control authority above transonic, but I doubt it -- it's not going to tumble ;) ).

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Also because reducing loads on the core may not be as important to this vehicle as it is to Ariane 5?
Reducing loads on the boosters means better mass fraction for all F9 boosters.

Side compressive loads on the booster core is the typical load holding the stack together, when you need it lower to max Q - the side TO cancels across the core's transverse loads bottom to top.

Also it that ULA is moving away from booster nose cones like that (the upgraded Atlas V SRBs have plain conical nose cones), so the benefits of them are clearly not significant.
The greater area/faster/longer duration of flight, the more it helps.

The benefit would be better mass fraction. If you fly enough, perhaps it matters. And its something you can do later if you want.

add:
Investigating the staging velocity and necessary choice implied, the height of the optimal tangent ogive would be above the core interstage, so perhaps there might be clearance issues with the core's gridfins that might complicate matters too.
« Last Edit: 12/23/2017 07:07 PM by Space Ghost 1962 »

Offline woods170

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #504 on: 12/23/2017 05:44 PM »
Because Ariane 5 doesn't care about recovering the side boosters?


Ariane 5 boosters are recovered.

Not quite correct Chuck. The booster for Ariane 5 have been recovered only a few times. It was for post-flight inspection to validate the design.

Standard MO for Ariane 5 boosters is to fall into the drink and sink.


But not reused?
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The possibility of refurbishing and reusing the recovered boosters has, however, been rejected. It is currently considered a non-cost-effective option because of the specific design and reliability complications that this would incur. It is currently planned to recover four boosters per year.
(from http://www.esa.int/esapub/bulletin/bullet85/gigo85.htm cited above by nacnud.)

Why bother? Seriously. There might be some minor learnings but if you're not even going to TRY to reuse them, it's just a big boondoggle.  Some contracts must have been let and then found to be too expensive to cancel, or something.

Recovery of the boosters proved to be extremely troublesome. The ELS package was experimental and unreliable. The very first recovery attempt failed completely because of that.

Even the planned four retrievals per year went away quickly after the first successful recovery validated the basic design of the boosters.

The fact that no humans were going to fly on Ariane 5 (after Hermes was cancelled) also aided the decision to not recover the boosters after the initial sets.
« Last Edit: 12/23/2017 05:50 PM by woods170 »

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #505 on: 12/26/2017 03:31 PM »
Usual amazing work by Oli Braun:

Quote
Some FH artwork :) available as high res prints anytime soon :) @NASASpaceflight @FHeavyBooster @SpaceXPad39A

https://twitter.com/oli_braun/status/945647229456527360

Usual amazing work by Oli Braun:

Quote
Some FH artwork :) available as high res prints anytime soon :) @NASASpaceflight @FHeavyBooster @SpaceXPad39A

https://twitter.com/oli_braun/status/945647229456527360

That guy is amazing
« Last Edit: 12/26/2017 04:03 PM by IanThePineapple »
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Online Johnnyhinbos

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #507 on: 12/26/2017 04:13 PM »
Wow - FH payload picture on the update thread. Thatís a First I believe! You can see the TEL inside. Does this mean a static fire with payload attached??
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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #508 on: 12/26/2017 04:18 PM »
https://twitter.com/elonmusk/status/943420026593337344

@elonmusk
Falcon Heavy at the Cape

As a tinker-toy construct, it seemed so obvious, but faced with the reality, I wonder how I ever thought this was going to work.  Imagining the staging is giving me the heebie jeebies.  Perhaps particularly after having reviewed Falcon 1 launches....

Wow - FH payload picture on the update thread. Thatís a First I believe! You can see the TEL inside. Does this mean a static fire with payload attached??

Possibly!

Either that or they're moving it there to free up space in the integration facility.
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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #510 on: 12/26/2017 04:29 PM »
Does this mean a static fire with payload attached??

Maybe just pictures before WDR?  Particularly if you can nab Zuma and FH on pads at the same time?

Offline WH2OPaddler

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #511 on: 12/26/2017 05:16 PM »
Now that the 1st FH is assembled, any word on when the static fire is planned?

Now that the 1st FH is assembled, any word on when the static fire is planned?

NET early January.

Offline russianhalo117

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #513 on: 12/26/2017 05:32 PM »
Now that the 1st FH is assembled, any word on when the static fire is planned?
First rollout may occur before the end of the year for a dry systems test with the fully integrated stack.
« Last Edit: 12/26/2017 05:37 PM by russianhalo117 »

Offline pospa

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #514 on: 12/26/2017 07:06 PM »
Great find. Higher res attached.

I would say we can also see for the first time FH integrated to TEL in the background darkness of HIF. :)
« Last Edit: 12/26/2017 07:11 PM by pospa »

Offline douglas100

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #515 on: 12/26/2017 07:43 PM »
Looks like there's another single core as well, parked to the right of the FH/TEL.
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Offline douglas100

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #516 on: 12/26/2017 07:47 PM »
Does this mean a static fire with payload attached??

Maybe just pictures before WDR?  Particularly if you can nab Zuma and FH on pads at the same time?

No reason why they can't do the static fire fully assembled. It's not like it's a customer's payload or anything. If they lose the vehicle on the pad then the loss of the Tesla is the least of their worries.
Douglas Clark

Offline cro-magnon gramps

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #517 on: 12/26/2017 08:06 PM »
I created a rough time line on Friday. The TEL integration was pre CHRISTMAS day with TEL fit check happening after boxing day. That led into a roll out around the weekend before NewYears Day. The static fire won't happen before ZUMA launches because they will be into pad Fit checks and the danger posed by an explosion on the pad at 39A. That leads to a Net  of Jan 11th to 15th for launch. AT LEAST that's my rationalization: :D
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Offline pospa

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #518 on: 12/26/2017 08:08 PM »
Looks like there's another single core as well, parked to the right of the FH/TEL.

That light ring is assembly jig only. No other boosters then FH in HIF right now.

Offline RocketLover0119

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Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
« Reply #519 on: 12/26/2017 08:17 PM »
Also tried my attempt at removing the darkness from the photo

Great find. Higher res attached.

I would say we can also see for the first time FH integrated to TEL in the background darkness of HIF. :)
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