Author Topic: General Falcon and Dragon discussion (Thread 13)  (Read 396563 times)

Offline macpacheco

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #600 on: 05/21/2016 03:06 am »
Just a reminder that SpaceX builds launchpads at a fraction of ULA/NASA costs.
They can afford to just throw it away and being anew if they think its better.
Trying to accuse SpaceX of falling prey to the Sunk Cost Fallacy makes very little sense. SpaceX is the epitome of doing things cost effectively, just saying.

Example, the Boca Chica Launch Complex is estimated at US$ 100 million total costs !
I would guesstimate LC40 costed less than the stated F9 FT first stage build cost.
« Last Edit: 05/21/2016 03:19 am by macpacheco »
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Offline The Amazing Catstronaut

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #601 on: 05/21/2016 05:19 am »
Just a reminder that SpaceX builds launchpads at a fraction of ULA/NASA costs.
They can afford to just throw it away and being anew if they think its better.
Trying to accuse SpaceX of falling prey to the Sunk Cost Fallacy makes very little sense. SpaceX is the epitome of doing things cost effectively, just saying.

Example, the Boca Chica Launch Complex is estimated at US$ 100 million total costs !
I would guesstimate LC40 costed less than the stated F9 FT first stage build cost.

Right. They could build a complex, abandon it and build another till the end of time with wanton abandon and it wouldn't cut into their profits in any critical way - and they have made a profit off all of their facilities so far, so such a scenario is rather unlikely.

SpaceX isn't very good at crappy economics.
« Last Edit: 05/21/2016 05:19 am by The Amazing Catstronaut »
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Offline Jim

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #602 on: 05/21/2016 01:14 pm »
Just a reminder that SpaceX builds launchpads at a fraction of ULA/NASA costs.


Wrong.  Don't lump NASA and ULA in the same group.  Complex 40 and 41 costs would be the same since Spacex has now upgraded to an EELV equivalent vehicle and if they added vertical integration hardware.

ULA pads were driven by vertical integration requirements and vehicle size.  The original F9 wasn't close to either.
« Last Edit: 05/21/2016 01:20 pm by Jim »

Offline Jcc

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #603 on: 05/21/2016 02:17 pm »
Well, I guess I'll let the question on potential use of F9DevR2 for in-flight abort go.  I really didn't get an answer that satisfies me.  But I think I might be rubbing people raw on this.

Knowing for a fact whether its possible to recover the booster would certainly affect the value of considering a F9DevR2.  Regardless, I don't personally care or prefer one choice over the other.  I really have just been asking the question sort of academically.  Its the making of the choice that matters more to me than what choice is made.

The response here smells a little of 'group think' to me.

What group?  And who is thinking?

Plain and simple, cheaper not to use F9R Dev2 than to use it at this point in history.

Probably a true statement.
Next, they have a choice between storing it in perpetuity, donating it to a space museum or cutting it apart for spare parts and recycling the metals. I would suggest the last option, if anything to prove you can, which may indicate an end of life path for reused stages. (Other than going expendable).
« Last Edit: 05/21/2016 02:22 pm by Jcc »

Offline woods170

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #604 on: 05/21/2016 08:10 pm »
I had a meeting with some of the conservators at Udvar-Hazy a couple of weeks ago, and in general conversation said, "I don't see any SpaceX hardware here." (thinking specifically of the line of 1/15 scale launch vehicle models in the Space wing.) They got very sour looks and said, "Bad topic." Turns out SpaceX is asking for substantial payments from the Air & Space Museum (at least, don't know if that's true for other museums or just the Smithsonian) for any of their old hardware. They're much more used to having people donate historically significant items to them.
What you was told is basically the same thing I was told last year when I had the chance to ask the Air & Space Museum a very similar question. Elon is clearly not in the business of giving away his old rocket & spacecraft hardware for free. I can understand that given the following example:
At our own little space museum over here in the Netherlands (and I don't mean ESTEC's Space Expo) we sought to obtain a (now defunct) piece of Columbus training hardware for our ISS exposition. Turned out that ESA had rented that particular piece of hardware from the manufacturer. Naturally the manufacturer was not interested at all in donating the training hardware to us. Despite the hardware being fully defunct they still expected us to pay a rather hefty sum of money to obtain the right to add it to the exposition. Given that our little museum works on a shoestring budget we declined.
« Last Edit: 05/21/2016 08:18 pm by woods170 »

Offline baldusi

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #605 on: 05/21/2016 08:39 pm »
The reason might be an accounting/taxation issue. If they keep those items at the production cost (including certification and such), to keep a certain equity amount in their balance sheet, then taking them out would have consequences.
Say that they need a certain equity because they need it when they bid to the government. If they had lots of profits, then they would probably like to reduce their income tax through such donations.
But if they don't currently have profits against which to offset those "losses" of the donation, Then taking them out would be a loss of equity. And in the short term impact their bidding strength and in the longer term force them to pay more income tax.
So I wouldn't be surprised if they had would be willing to donate in the future.

Offline the_other_Doug

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #606 on: 05/21/2016 09:11 pm »
The reason might be an accounting/taxation issue. If they keep those items at the production cost (including certification and such), to keep a certain equity amount in their balance sheet, then taking them out would have consequences.
Say that they need a certain equity because they need it when they bid to the government. If they had lots of profits, then they would probably like to reduce their income tax through such donations.
But if they don't currently have profits against which to offset those "losses" of the donation, Then taking them out would be a loss of equity. And in the short term impact their bidding strength and in the longer term force them to pay more income tax.
So I wouldn't be surprised if they had would be willing to donate in the future.

Yes, but you get around that kind of thing by placing the item in question "on loan" to the museum.  Thus it remains the property of the manufacturer, but is available for display.

I would imagine that such things might become a little more complicated if the manufacturer and the museum are in two different countries, though.
-Doug  (With my shield, not yet upon it)

Offline Lars-J

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #607 on: 05/22/2016 12:56 am »
All of that said, F9DevR2 simply doesn't fit properly on any of the F9 launch facilities any longer.  Because the latest version of the F9 has stretched tanks compared to those in the F9DevR2

The upper stage tanks were stretched, yes, but I don't think that the first stage were.

Yet several people have made this assertion, but I have yet to see any real source for it. Can someone cite some real evidence of a 1st stage tank stretch after v1.1?

Offline mvpel

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #608 on: 05/22/2016 01:02 am »
1.  No assumption, they are. 
I'd love to have the source/reference for that.  Really.

Jim's post, above.  ;)
"Ugly programs are like ugly suspension bridges: they're much more liable to collapse than pretty ones, because the way humans (especially engineer-humans) perceive beauty is intimately related to our ability to process and understand complexity. A language that makes it hard to write elegant code makes it hard to write good code." - Eric S. Raymond

Offline Lars-J

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #609 on: 05/22/2016 02:59 am »
1.  No assumption, they are. 
I'd love to have the source/reference for that.  Really.

Jim's post, above.  ;)
I'm afraid I'm going to need something more, since it appears to contradict other things we have heard/seen since the FT F9 arrived.

See image describing F9 FT changes - a first stage tank change or tank change is not listed:
« Last Edit: 05/22/2016 03:01 am by Lars-J »

Offline Mongo62

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #610 on: 05/22/2016 03:07 am »
I'm afraid I'm going to need something more, since it appears to contradict other things we have heard/seen since the FT F9 arrived.

See image describing F9 FT changes - a first stage tank change or tank change is not listed

One change not mentioned in that image is the location of the common bulkheads between the LOX and RP-1 tanks. With sub-cooling, the density of the RP-1 increases and the LOX/RP-1 volume ratio changes, hence requiring that the common bulkheads move to increase the volume of LOX and reduce the volume of RP-1.

I do not know this for certain, but it seems plausible that this might also require the locations of the propellant loading ports to shift as well.

Offline Lars-J

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #611 on: 05/22/2016 04:38 am »
See image describing F9 FT changes - a first stage tank change or tank change is not listed

One change not mentioned in that image is the location of the common bulkheads between the LOX and RP-1 tanks. With sub-cooling, the density of the RP-1 increases and the LOX/RP-1 volume ratio changes, hence requiring that the common bulkheads move to increase the volume of LOX and reduce the volume of RP-1.

I do not know this for certain, but it seems plausible that this might also require the locations of the propellant loading ports to shift as well.
Do we have any corroborating evidence that the common bulkhead has moved, other than a terse and possibly ambiguous Jim statement?

And propellant loading/dumping ports on the 1st stage are at the base.

Offline guckyfan

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #612 on: 05/22/2016 05:54 am »
One change not mentioned in that image is the location of the common bulkheads between the LOX and RP-1 tanks. With sub-cooling, the density of the RP-1 increases and the LOX/RP-1 volume ratio changes, hence requiring that the common bulkheads move to increase the volume of LOX and reduce the volume of RP-1.

I expect it to be the other way around. RP-1 is densified by cooling. However LOX is densified more than that and probably the RP-1 tank volume would increase. But I don't recall this ever mentioned before now.

Online oldAtlas_Eguy

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #613 on: 05/22/2016 03:03 pm »
It is more of a structural strength problem and US weight problem in using the v1.1 tank with FT engines. The tank cannot handle the higher loads of a 20mt heavier US and the 16% higher thrust FT engines without thrust limiting at liftoff. With the heavier US optimized for the FT 1st stage not the v1.1 1st stage the resulting vehicle may even have less performance than the original v1.1.

For a tank that costs <$8M it is not worth using it with engines that do not exist on it as it was to be used (only 3 normal thrust [non-FT]) and must be added. If you add 6 other FT engines then it is best to also replace the other 3 but to use the 9 FT engines you need to modify the thrust structure or replace it now that tank savings gets less and less and the headaches mount. You end with a Frankenstein one of a kind stage neither a v1.1 or a FT.

Offline edkyle99

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #614 on: 05/22/2016 03:13 pm »
All of that said, F9DevR2 simply doesn't fit properly on any of the F9 launch facilities any longer.  Because the latest version of the F9 has stretched tanks compared to those in the F9DevR2

The upper stage tanks were stretched, yes, but I don't think that the first stage were.

Yet several people have made this assertion, but I have yet to see any real source for it. Can someone cite some real evidence of a 1st stage tank stretch after v1.1?
Only the second stage was stretched, not the first stage.  The erector tower had a section added to adapt to the slightly-taller rocket.  This was discussed at length last year.

 - Ed Kyle

Offline BobHk

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #615 on: 05/22/2016 03:13 pm »
Just a reminder that SpaceX builds launchpads at a fraction of ULA/NASA costs.
They can afford to just throw it away and being anew if they think its better.
Trying to accuse SpaceX of falling prey to the Sunk Cost Fallacy makes very little sense. SpaceX is the epitome of doing things cost effectively, just saying.

Example, the Boca Chica Launch Complex is estimated at US$ 100 million total costs !
I would guesstimate LC40 costed less than the stated F9 FT first stage build cost.

Right. They could build a complex, abandon it and build another till the end of time with wanton abandon and it wouldn't cut into their profits in any critical way - and they have made a profit off all of their facilities so far, so such a scenario is rather unlikely.

SpaceX isn't very good at crappy economics.

https://www.youtube.com/watch?v=lnbOUgmazxE&feature=youtu.be

Take this as an indication of agility - quick and cheap build of SLC40 for Spacex

Offline douglas100

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #616 on: 05/22/2016 03:50 pm »
Just to point out that SpaceX hasn't actually built a pad from scratch yet. They have modified two existing pads and are working on a third modification currently. Only when the work in Texas is finished will they have completely built a pad. However I am making no claims about SpaceX's construction costs versus other launch providers.
Douglas Clark

Online LouScheffer

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #617 on: 05/22/2016 04:05 pm »
Well, I guess I'll let the question on potential use of F9DevR2 for in-flight abort go.  I really didn't get an answer that satisfies me.  But I think I might be rubbing people raw on this.
I think you are bugging folks by searching for a reasoning that is not publically available.

With only knowledge of how expensive technical decisions normally get made, I'd bet it was something like this one of these scenerios:

There was a meeting about "which booster for abort test?".  At this meeting, engineers outlines the pros and cons.  On the plus side, it already exists.  On the minus side, you'd need to retrofit the GSE, launch, re-fit the pad and re-qualify it.  They would have, or estimate at the meeting, the costs for this and any effects on follow-on schedules.  Also, the test is not as realistic with an old booster (does NASA care?).  Plus there may be operational problems, such as people trained for a 1.1 launch that have left.  Their replacements may only be trained for 1.2.  Another consideration, not known when they spec'd the F9DevR2, is that they have used boosters available.

Or maybe this all happened at the "GSE update for Vandenburg" meeting, when it was pointed out this would make using the F9DevR2 much harder.

At any rate, at some point they considered all these issues, and decided it was better to not use the F9DevR2.  Short of an insider, directly involved with this issue, writing some retrospective history of the F9, you are not likely to get a complete explanation.  It's also likely there is no "smoking gun" killer issue - any individual issue could have been addressed, but the combination of all the hassles made it  better to drop the F9devR2.  It may not be satisfying to you, but it's all you are likely to get.  Asking for more, as you yourself point out, is just bugging folks. 

Offline Lar

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #618 on: 05/22/2016 04:22 pm »
A bit less challenging each other would be good.  Also we don't need to dissect why Jim chose to be extraordinarily patient, either.
« Last Edit: 05/22/2016 08:40 pm by Lar »
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Offline the_other_Doug

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Re: General Falcon and Dragon discussion (Thread 13)
« Reply #619 on: 05/22/2016 04:38 pm »
So, an odd question -- an in-flight abort test is usually a max-Q abort test.  An abort at max-Q is the toughest one to pull off, for obvious reasons.  I recall that Mercury and Apollo weren't qualified to fly crews until they had passed a max-Q abort test.

So, let's assume that the Dragon 2 in-flight abort test will happen at max-Q.  To "test as you fly," they will need to have the rocket carry a dummy second stage between the first stage and the Dragon 2 trunk, right?

So... what I'm trying to picture is how the first stage will handle after a max-Q abort, and is there a sequence of dumping the dummy stage 2 and then a boostback burn that would allow the first stage to be recovered?  Will the likelihood that stage 1 will only fly on three engines make a difference?

Unless the dummy second stage is more aerodynamic that your normal flat-ended top end of a real stage 2, when you pull the trunk and Dragon off, at max-Q, will the booster and dummy stage 2 be controllable?  Even if the engines are shut down right after the Dragon and trunk clear their path?  Or is that a recipe for the stage coming apart, no matter what you do?

I guess I'm trying to get some idea in my head as to how likely it is the booster used for this test can be recovered.  Any thoughts?
-Doug  (With my shield, not yet upon it)

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