Author Topic: SpaceX: General Falcon and Dragon discussion (Thread 4)  (Read 756389 times)

Offline MP99

Flight 7 is the 3rd CRS flight. It could have a single Merlin 1D in the center position. This would enable gathering flight data on the Merlin 1D performance without posing significant mission risk. There could be as many as 3 flights of F9 prior to FH with 1Dís. It is also possible that the stretched tank version may not even fly on the first FH. This would still give FH a 32-38MT capability even with short tanks and active propellant cross-feed. I believe that from a business standpoint of managing yearly outlays and trying out one thing at a time to manage risks it is a possible scenario. With the longer tanks being done post 2013 when a increase in capability of both F9 and FH would be a feature to keep SpaceX ahead of the pack in $/kg to LEO and the ever slowly increasing weight of payloads.

Gwynne actually equivocated while discussing if cross-feed would be on the first FH flight.  At the time (this was at the Space Access 2011 Conference in early April) she may have been expressing a personal rather than "official" opinion, since this presentation took place a day or two after the press conference.  But I think upon reflection that SpaceX has realized if they fly w/o cross-feed on the first flight, they'd basically have to fly another test with, doubling their costs and taking an extra few months to a year to get to where they want to be.  So it really makes no sense to test w/o it.

The flip side of that is that even without crossfeed, FH has enough capacity to carry all existing payloads at a price no existing launcher can match. There are no payloads, existing or planned, that are too heavy for a FH without crossfeed that could be lifted by a FH with crossfeed. By putting crossfeed in the critical path for FH testing, they're potentially delaying operational capability for the FH if anything goes wrong with crossfeed, at no incremental market gain.

So the contrary view is that they'd be better off introducing FH without crossfeed to gain market share as rapidly as possible, then introduce crossfeed later as an upgrade when there could be a market for it.

Don't forget that SpaceX must have a successful flight with both a performance upgrade and a PLF before they can undertake the SES launch, which is early 2013 and directly after the FH demo.

I wonder if SpaceX are planning to make FH the test / demo flight for all the features required by SES, including core with 9x M1D & the PLF. (Or is the "2011" MDA flight going to demonstrate the PLF in 2012?)

If FH must fly before SES, then ISTM they must pare this flight down to the essentials, which means no cross-feed, and maybe no core stretch.



Another thought re cross-feed. Assume the demo flight doesn't have it, and the first few paid flights don't need it. Could they fly one of the early FH missions with cross-feed active, but not detach the outriggers when they burn out? It would be a partial test, at the cost that the outriggers would be hanging in the latter part of the first stage burn. I'm not sure if FH needs to be designed to cope with this load path anyway during the short period between outrigger burnout and separation.

cheers, Martin

Offline Nomadd

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #41 on: 06/21/2011 01:32 pm »
ess 2011 Conference in early April) she may have been expressing a

Another thought re cross-feed. Assume the demo flight doesn't have it, and the first few paid flights don't need it. Could they fly one of the early FH missions with cross-feed active, but not detach the outriggers when they burn out? It would be a partial test, at the cost that the outriggers would be hanging in the latter part of the first stage burn. I'm not sure if FH needs to be designed to cope with this load path anyway during the short period between outrigger burnout and separation.

cheers, Martin

 I'd always wondered about the loads at separation. But somehow I doubt if they'd care for the idea of dragging two dead cores along. The only reason would be to be sure crossfeed worked right before you dropped the cores. The problem is, if it didn't work right, it would mean you'd still have fuel or O2 in one or both cores and you'd have to drag that extra weight along if you didn't drop them.
  I wonder if they'll be able to kill crossfeed if anything goes wrong and stage later or just use all three cores to salvage the mission. Might make a difference between a shortened satellite or whatever mission and launching into the ocean.
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Offline kevin-rf

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #42 on: 06/21/2011 01:41 pm »
Might make a difference between a shortened satellite or whatever mission and launching into the ocean.

I think you would still end up in the ocean in that case. The margins are not usually there, just look at the last Orbital launch where a fairing separation failure resulted in the vehicle to heavy to even be able to make orbit. I suspect dragging the outriggers along, or canceling cross feed early result in a similar swan song.
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Offline go4mars

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #43 on: 06/21/2011 02:48 pm »
The crossfeed FH is grossly over-sized for existing payloads, but that would give you a lot of mass for recovery hardware.

Exactly.  I think a lot of folks underestimate this reasoning. 
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Offline Jorge

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #44 on: 06/21/2011 03:06 pm »
We don't know what discussions SpaceX has had with potential customers.  There may be payloads planned for the near future that require crossfeed. 
Doubtful. Almost anything that big will take a long time to develop and cost a lot of money. If there are customers who want that kind of payload, it's extremely unlikely they will commit significant money until there is high confidence in F9-H ability to meet the claimed numbers. That suggests that serious engineering on this kind of payload would not have started yet, and any flight would be years away.

Multiple heavy comsats could work, but there's little motivation for that. Launching them singly on a regular F9-H would still be cheaper the current market rate, and launch costs isn't really a driver for those payloads even now.

Elon did say he's got potential customers for the FH flights two to four that they're talking with.  Can't for the life of me think who they might be unless it's Bigelow and/or NASA.   

Me neither. But Bigelow just announced the BA-2100 which is too big (65 tons) for the FH even with crossfeed, and their next smaller module can fly on an FH without crossfeed. And NASA is designing for SLS (70+ tons).
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Offline Lurker Steve

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #45 on: 06/21/2011 03:11 pm »
On the topic of SpaceX employees I've been having a bit of fun reading spacex employee reviews from GlassDoor.com

http://www.glassdoor.com/Reviews/Space-Exploration-Technologies-Reviews-E40371.htm

As always take these with a hefty lump of salt and these reviews always trend to the negative. Some of these reviews may indicate the normal problems of a quickly growing company.
I think the negative reviews fit within what Gwen and others have said about SpaceX, specifically how "fitting in" is key and people who don't won't be staying long. For good or ill that's how they tick.

Should we be suprised about the Low pay comments ? If Elon really wants the best and brightest, his wages shouldn't be at the low end of the scale.

Promoting technical people who have no management skills into management roles is a typical problem with growing companies. Many skilled technical people need to stick with what they are good at, and stay away from management roles. I seldom find good engineers that are good managers. Having High School "clicks" isn't productive.

Offline mrmandias

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #46 on: 06/21/2011 03:55 pm »
Another possible wrinkle in this is stage re-use: The crossfeed FH is grossly over-sized for existing payloads, but that would give you a lot of mass for recovery hardware.

True, but the more effective SpaceX gets at reducing engine costs through mass production, the less benefit to recovery and reuse.  Of course there's a lot more to the rocket than just the engines, but the engines are commonly thought to be the easiest component to reuse.

Offline mrmandias

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #47 on: 06/21/2011 04:00 pm »
Should we be suprised about the Low pay comments ? If Elon really wants the best and brightest, his wages shouldn't be at the low end of the scale.

SpaceX probably isn't paying chicken scratch, but I bet the big payola comes in the form of stock options.  That fits with Musk's Silicon Valley start-up model.

The problem is that most start-ups don't have SpaceX's eleemosynary aspect.  Dangling stock options to tempt employees to work like dogs for mediocre pay isn't really consistent with your CEO telling everyone who'll listen that he is willing to forego profits to get to Mars.

Offline Blackjax

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #48 on: 06/21/2011 04:40 pm »
I'm seeing a lot of comments puzzling over why SpaceX needs the extra lift capacity.  Is it possible that they are doing that because it allows a larger variety of secondary payloads to be able to launch on any given flight?  Wouldn't this help them service the market better because they would be able to offer a very robust & flexible secondary payload service and possibly launch those payloads on more aggressive timelines than might be possible otherwise?  Another possibility might be that it enables them to operate with much higher margins for engine out scenarios to help boost the reliability picture they present to prospective customers. 

Offline Jason1701

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #49 on: 06/21/2011 04:51 pm »
Should we be suprised about the Low pay comments ? If Elon really wants the best and brightest.

You're extrapolating from a single data point. If one person thinks he doesn't get paid enough, and says so on the internet, that doesn't mean any others feel that way.

Offline Antares

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #50 on: 06/21/2011 04:55 pm »
Dangling stock options to tempt employees to work like dogs for mediocre pay isn't really consistent with your CEO telling everyone who'll listen that he is willing to forego profits to get to Mars.

Careful.  They'll sue you ;)
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Offline oldAtlas_Eguy

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #51 on: 06/21/2011 05:48 pm »
As I briefly touched on before the core configuration flying Merlin 1Dís including the FH, is controlled by SpaceX available funds to do pad mods (VAFB and Cape), tank redesign, FH design (flight software and flight modeling in detail and three core engine tests on VAFB pad), and when the 1Dís enter production:

1) Pad mods: VAFB pad is being built to handle the longer tanks and higher thrusts of the Merlin 1Dís, the Cape processing building is too short to handle longer tanks. So when longer tanks fly out of the cape and possibly even FH is solely based on when SpaceX starts doing the pad mods at the Cape, which is another monetary outlay not in SpaceXís budget because the performance of the Merlin 1Dís was a pleasant surprise and not a planned one. If anyone has any information of when Cape pad mods would start this would cut down on speculation?

2) Tank redesign: Another engineering effort and possible retooling in order to manufacture longer tanks. The aerodynamic and flight control elements of using a longer tank must be examined and modeled in detail as well for single core F9. Some of the modeling could be covered by the FH work lowering costs. This is another un-budgeted item and is not required and is a low risk item for introduction at a later time when SpaceX has more money. If anyone knows if the engineering effort and retooling for longer tanks has started or when it will start this too will cut down on speculation?

3) FH design: It will probably make sense to do this only once with longer tanks up front. Actual tank length is a function of engine performance. Actual Merlin 1D performance is still a question mark but we have a min and max value of expected (>=130,000lbf and <=140,000lbf).

4) Production Merlin 1D availability: Indications are that SpaceX has a good handle on what the production engines will be performance wise but there is still some variableness in the numbers until such time a production 1D is tested on a stand. The other item is when 1Dís will be available for incorporation onto a F9. The current info is the 7th F9 flight, but since the date of the flights keep moving to the right even that may be wrong.

There are many unfilled holes in the schedule of when and in what order efforts will take place. SpaceX has put out its first draft of the FH specs but we donít know how much of that is backed by hard engineering performance numbers. The assumption is that cross-feed will work as envisioned, the tanks will be stretched and the Merlin 1Dís performance will be 140,000+lbf. We have seen already how SpaceX has struggled to meet its goals with the current F9 version. So what will the first FH look like and what will incorporate, we only have speculation at this point.
« Last Edit: 06/21/2011 05:53 pm by oldAtlas_Eguy »

Offline Nomadd

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #52 on: 06/21/2011 06:29 pm »

Promoting technical people who have no management skills into management roles is a typical problem with growing companies. Many skilled technical people need to stick with what they are good at, and stay away from management roles. I seldom find good engineers that are good managers. Having High School "clicks" isn't productive.


 Elon isn't the only one who disagrees with you. I've seen many good companies go to hell because they started hiring management "professionals" with no experience in the field they were managing. 
 I'll always be in favor of bringing management from the ranks.
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Offline Nate_Trost

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #53 on: 06/21/2011 06:49 pm »
Bringing a non-technical manager in to manage engineers is a disaster. But bringing in an experienced engineering manager from another technical field is a better bet than trying to promote engineers with no aptitude (or even worse, lack of any real desire) to manage.
« Last Edit: 06/21/2011 06:50 pm by Nate_Trost »

Offline Lurker Steve

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #54 on: 06/21/2011 07:01 pm »
Should we be suprised about the Low pay comments ? If Elon really wants the best and brightest, his wages shouldn't be at the low end of the scale.

SpaceX probably isn't paying chicken scratch, but I bet the big payola comes in the form of stock options.  That fits with Musk's Silicon Valley start-up model.

The problem is that most start-ups don't have SpaceX's eleemosynary aspect.  Dangling stock options to tempt employees to work like dogs for mediocre pay isn't really consistent with your CEO telling everyone who'll listen that he is willing to forego profits to get to Mars.

What good are stock options in a private company ?

Offline Lurker Steve

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #55 on: 06/21/2011 07:04 pm »
Should we be suprised about the Low pay comments ? If Elon really wants the best and brightest.

You're extrapolating from a single data point. If one person thinks he doesn't get paid enough, and says so on the internet, that doesn't mean any others feel that way.

There were about 5 or 6 comments on this "Glass Door" site. Most of them mentioned the low wages compared to the rest of the industry.  Perhaps these comments are coming from ex-SpaceX employees.

Online Robotbeat

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #56 on: 06/21/2011 07:05 pm »
Should we be suprised about the Low pay comments ? If Elon really wants the best and brightest, his wages shouldn't be at the low end of the scale.

SpaceX probably isn't paying chicken scratch, but I bet the big payola comes in the form of stock options.  That fits with Musk's Silicon Valley start-up model.

The problem is that most start-ups don't have SpaceX's eleemosynary aspect.  Dangling stock options to tempt employees to work like dogs for mediocre pay isn't really consistent with your CEO telling everyone who'll listen that he is willing to forego profits to get to Mars.

What good are stock options in a private company ?

SpaceX representatives have mentioned an IPO.
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Offline Lurker Steve

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #57 on: 06/21/2011 07:14 pm »
Bringing a non-technical manager in to manage engineers is a disaster. But bringing in an experienced engineering manager from another technical field is a better bet than trying to promote engineers with no aptitude (or even worse, lack of any real desire) to manage.

I didn't say non-technical, but managers need to know how to manage people. The best technical people are wasted in management roles, because they don't (or at least shouldn't) have time to use their technical talents. Managers spend their time acquiring and managing the resources that their staff require, filter out the noise / BS from above, and basically let the engineers do their job. If a manager still thinks they have time for actual engineering, they are wrong.

Online hop

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #58 on: 06/21/2011 08:42 pm »
I'm seeing a lot of comments puzzling over why SpaceX needs the extra lift capacity.  Is it possible that they are doing that because it allows a larger variety of secondary payloads to be able to launch on any given flight?
Doesn't really add up IMO. The biggest GEO comsats are ~6-7 tons. FH is claimed to be ~19 tons to GTO.

Secondary payloads have a lot of constraints. Anything decent sized not going to GEO will probably want to be in a specific orbit that isn't compatible with a GEO launch. Secondaries also add complexity and risk, which is not something people with big expensive payloads are going to be enthusiastic about. Big payloads are relatively rare and take a long time to build, so there aren't that many opportunities to launch more than one at at time.

Note that Arainespace is trying to get away from multi-payload launches with Araine 6. They do it on Araine 5 because it's too big, not because launching multiple payloads at once is desirable. Araine 5 ECA has been able to put a ~10 ton payload into GTO for a long time, but no one has built one. That suggests launcher capacity isn't limiting the market for huge comsats.

Offline go4mars

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Re: SpaceX: General Falcon and Dragon discussion (Thread 4)
« Reply #59 on: 06/21/2011 11:20 pm »
I'm seeing a lot of comments puzzling over why SpaceX needs the extra lift capacity. 
Doesn't really add up IMO. The biggest GEO comsats are ~6-7 tons. FH is claimed to be ~19 tons to GTO.

Secondary payloads ... also add complexity and risk...Big payloads are ... rare and take a long time to build

Personally, I think that excess capacity will be usually used for reusability hardware.  Chutes, a few mm of Pica-X, internal tank cables/bracing, etc.   

my WAG: Flying regular-sized satellites on a FH will be the rule, rather than the exception.  The first 20 flights might all not be reusable (try though they may), but flight 21 of FH, they might recover an intact stage.  Then boom; launch costs go down like the value of the US dollar.  For flights that require 40 or 50 tonnes, the recovery hardware gets stripped off and it's a regular expendable again.  Ta-da.   


the more effective SpaceX gets at reducing engine costs through mass production, the less benefit to recovery and reuse.

Hope for the best, plan for the worst or the best.
« Last Edit: 06/21/2011 11:25 pm by go4mars »
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