Author Topic: SpaceX Falcon 9 (F9-23 : S/N 1021) KSC Reuse Testing Coverage  (Read 79043 times)

Online CorvusCorax

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #40 on: 04/20/2016 03:37 PM »
Well, considering they still regularly do full thrust full duration burns at Mc Gregor, they should know what a flame trench needed for that has to go through.

It's of course possible that the pad 39a flame trench isn't rated for that abuse, but if I remember right they did make modifications to it, so it could be. What better way of putting the pad infrastructure through its paces than a full duration burn.

Or 10 of them.

That would be an awesome tourist spectacle!
By the way, does the cape has anything similar to rocket cows? Rocket alligators maybe?

Offline rpapo

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #41 on: 04/20/2016 03:42 PM »
Rocket alligators maybe?
See at about 1:20 into to this video:
« Last Edit: 04/21/2016 11:51 AM by rpapo »
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Offline neoforce

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #42 on: 04/20/2016 03:43 PM »
Isn't there a second benefit of doing multiple static fires at 39A?  In addition to testing the stage, it  gives a very thorough workout of the ground support equipment prior to first launch there. 

Offline Jim

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #43 on: 04/20/2016 04:47 PM »

It's of course possible that the pad 39a flame trench isn't rated for that abuse, but if I remember right they did make modifications to it, so it could be. What better way of putting the pad infrastructure through its paces than a full duration burn.


Hold downs are more of a consideration.  Launch pads typically don't deal with an almost empty stage at full thrust.

Online abaddon

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #44 on: 04/20/2016 05:22 PM »
Hold downs are more of a consideration.  Launch pads typically don't deal with an almost empty stage at full thrust.
So maybe they're thinking 10 static fires of 18s in duration each, or whatever.  Similar total burn time, less head load on everything, and the rocket would still be relatively full after 18s of burn.

Offline Herb Schaltegger


It's of course possible that the pad 39a flame trench isn't rated for that abuse, but if I remember right they did make modifications to it, so it could be. What better way of putting the pad infrastructure through its paces than a full duration burn.


Hold downs are more of a consideration.  Launch pads typically don't deal with an almost empty stage at full thrust.
There's a bit of info in L2 about this subject.
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Offline Meltro

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #46 on: 04/20/2016 05:40 PM »
Hold downs are more of a consideration.  Launch pads typically don't deal with an almost empty stage at full thrust.
So maybe they're thinking 10 static fires of 18s in duration each, or whatever.  Similar total burn time, less head load on everything, and the rocket would still be relatively full after 18s of burn.

You're assuming they're going to top it off, which is possible, but even if they do you're still missing a second stage worth of fuel and a payload. Some quick and dirty calculations suggest that without the second stage and payload, you're adding in the realm of 50% to the strain on those hold downs. If it's a mostly empty stage, we're talking anywhere from 300% on up to the increase in strain, each hold-down taking up to 325,000 lbf of tension, over 162 tons a piece. Even if the hold-downs could take that kind of strain, I have to wonder what the attachment points on the thrust plate are rated for.

EDIT: I realize the thrust plate does take the full force of the engines and weight of the rocket, I'm just wondering how much the load paths are affected.
« Last Edit: 04/20/2016 05:59 PM by Meltro »
Right you are, Ken

Offline Saabstory88

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #47 on: 04/20/2016 05:49 PM »
Would the hold-down mechanisms be significantly different than at McGregor? One the one hand, specialized components can be used for different tasks. On the other hand, having the same type of hold-downs across facilities reduces the variety of devices to be made and maintained. The hold-downs and McGregor can handle long duration burns sans payload and upper stage, so that should at least answer the question of whether or not the vehicle can handle the loads, right?

Offline Jim

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #48 on: 04/20/2016 06:07 PM »
Would the hold-down mechanisms be significantly different than at McGregor?

Yes, McGregor doesn't need a launch release.  Stages can be bolted down vs a release mechanism

Offline rcoppola

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #49 on: 04/20/2016 06:10 PM »
What are the chances, knowing they were going to be doing this kind of testing at 39A, that they built in the ability to bypass the launch release hold-downs and bolt the stage to the plate as they do in TX?
« Last Edit: 04/20/2016 06:12 PM by rcoppola »
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Online abaddon

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #50 on: 04/20/2016 06:16 PM »
You're assuming they're going to top it off, which is possible, but even if they do you're still missing a second stage worth of fuel and a payload. Some quick and dirty calculations suggest that without the second stage and payload, you're adding in the realm of 50% to the strain on those hold downs. If it's a mostly empty stage, we're talking anywhere from 300% on up to the increase in strain, each hold-down taking up to 325,000 lbf of tension, over 162 tons a piece. Even if the hold-downs could take that kind of strain, I have to wonder what the attachment points on the thrust plate are rated for.

EDIT: I realize the thrust plate does take the full force of the engines and weight of the rocket, I'm just wondering how much the load paths are affected.
Unless we expect SpaceX to add a new second stage to the recovered booster for the purpose of the 10 static fires, I am not sure I see much of a difference between a "regular" static fire (~3 seconds, engines allowed to ramp up to full thrust) and a slightly longer static fire.  Obviously the peak force would be applied longer, but it should not be greater than that experienced by a normal static fire.

I guess it is possible SpaceX is planning on putting a second stage slated for whatever flight the reflown booster will be assigned to for the series of "ten" static fires, but that seems less likely to me.

Offline OxCartMark

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #51 on: 04/20/2016 06:27 PM »
I suspect as posted above that SpaceX has given this some thought and has a solution that mirrors their TX experience.  Or not, I don't know.

What about the water deluge?  That's something that doesn't usually need to be recycled quickly.  What is the replenishment rate?  And of separate curiosity, what is the source, 39A well or KSC well system or municipal water supply?  Does the water have an adequate place to go once its sprayed about or does it require manual pumping to remove it?  Or are there retention ponds that it flows to that would quickly fill to capacity and need a significant period of time for the water leach into the ground?  Any limitations in the ability (if there is any system at all) to skim hydrocarbons from the water?

What is the total deluge time for a full water tower?  How long is the deluge activated for before and after a firing?

Then with this information the next thing I'm wondering is how many tanking events will be needed based only on loss of propellant supercooling during water management.

Offline The Roadie

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #52 on: 04/20/2016 06:29 PM »
Well, considering they still regularly do full thrust full duration burns at Mc Gregor,
Do you have any links to more than one at full duration? The FB group I help administer has some very nearby sources, and they're not seeing any after the first. Full duration engine tests on the single engine test site to the southeast, yes.

After getting data on one FD test in McGregor, and now more than one successful launch, they might have enough data on the performance to not invest the propellant on each and every core for full duration. I'm not seeing them omit the pad-based hot fire as ULA does, but full duration might be a thing of the past in McGregor, to the delight of the Rocket Cows and disappointment in the locals who enjoy the tests with their beer.
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Offline Meltro

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #53 on: 04/20/2016 06:30 PM »
I guess it is possible SpaceX is planning on putting a second stage slated for whatever flight the reflown booster will be assigned to for the series of "ten" static fires, but that seems less likely to me.

Y'know, that 'second stage' could be just a giant concrete block if they wanted. Fill 'er up, give it a hat, and keep it fed during firing = no additional strain on hold downs. It's not glamorous, but vs re-engineering the whole pad...
Right you are, Ken

Offline Jim

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #54 on: 04/20/2016 06:36 PM »

and keep it fed

That requires re-engineering

Offline StuffOfInterest

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #55 on: 04/20/2016 06:39 PM »
I'm not sure about needing a weighted mass simulator to test from the pad but I could see them bringing in a dummy upper stage for one simple reason.  If the rocket has an upper stage on it they can use the transporter-erector to move the rocket to and back from the pad instead of having to use a crane.

Offline Meltro

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #56 on: 04/20/2016 06:43 PM »

and keep it fed

That requires re-engineering

Fuel pumps don't have enough flow to keep it supplied? I know the fueling process takes a while, but I'd assumed they had a bit of leeway on how fast they pumped it in.

I'm not sure about needing a weighted mass simulator to test from the pad but I could see them bringing in a dummy upper stage for one simple reason.  If the rocket has an upper stage on it they can use the transporter-erector to move the rocket to and back from the pad instead of having to use a crane.

Thought about that, but the dummy would need to weigh as much as a loaded stage, and I think the TE moves the rocket dry.
Right you are, Ken

Offline StuffOfInterest

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #57 on: 04/20/2016 06:45 PM »
I'm not sure about needing a weighted mass simulator to test from the pad but I could see them bringing in a dummy upper stage for one simple reason.  If the rocket has an upper stage on it they can use the transporter-erector to move the rocket to and back from the pad instead of having to use a crane.

Thought about that, but the dummy would need to weigh as much as a loaded stage, and I think the TE moves the rocket dry.

Sorry, by dummy I meant to the correct size not weight.  Just something for the TE to grab on to.

Offline Kaputnik

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #58 on: 04/20/2016 07:05 PM »

and keep it fed

That requires re-engineering

Fuel pumps don't have enough flow to keep it supplied? I know the fueling process takes a while, but I'd assumed they had a bit of leeway on how fast they pumped it in.

I'm not sure about needing a weighted mass simulator to test from the pad but I could see them bringing in a dummy upper stage for one simple reason.  If the rocket has an upper stage on it they can use the transporter-erector to move the rocket to and back from the pad instead of having to use a crane.

Thought about that, but the dummy would need to weigh as much as a loaded stage, and I think the TE moves the rocket dry.

The stage empties itself in about two and a half minutes, vs half an hour to load prop. No way can the pumps keep pace with it.
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Online rds100

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Re: SpaceX Falcon 9 (F9-S1-0023) KSC Reuse Testing Coverage
« Reply #59 on: 04/20/2016 07:05 PM »
How about building some relatively simple and cheap S2+payload mass simulator / dummy and launching the recovered stage with it, instead of a real S2? Why risk a real S2 and real payload on the first refly?
Would that make sense?


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