Author Topic: BO vs SpaceX - development methods  (Read 15732 times)

Online Confusador

  • Full Member
  • **
  • Posts: 200
  • Liked: 41
  • Likes Given: 186
Re: BO vs SpaceX - development methods
« Reply #20 on: 01/26/2016 03:55 PM »

SpaceX: established in 2002, first paid launch in 2010 (?) and that launch was to orbit, already is making profit.
Reusable orbital first stage.


That's interesting. Do you have official numbers backing up the claim about profitability?

Oh man, we're going to get into the accounting discussion again, aren't we.  Not really a good topic on this board if you're looking for precision (engineering on the other hand, we can do).  Neither company is profitable from an investor's perspective (they're both still in growth), but that's not really what we're talking about.  No SEC filings means we don't get good numbers, but I'd wager on 3 things about SpaceX:

1) Manufacturing and launch operations as a division are profitable, but
2) that money gets funneled into R&D which means the company as a whole isn't even though
3) they don't require cash infusions to continue operating.

Blue on the the other hand doesn't have any divisions that are profitable.  They only have R&D at this point, and although they are generating some revenue from it they still need support from Bezos to operate.  It will be interesting to see if they can transition this year to having profitable operations from science flights.

Offline nadreck

Re: BO vs SpaceX - development methods
« Reply #21 on: 01/26/2016 04:52 PM »

2) that money gets funneled into R&D which means the company as a whole isn't even though


Now that depends on the accounting, if you consider R&D to be all expense then no they are spending in total more than they take in. However, if you consider R&D a capital investment like building a factory or buying land that continues to have value after you have spent the money on it, then they are in fact profitable.
It is all well and good to quote those things that made it past your confirmation bias that other people wrote, but this is a discussion board damnit! Let us know what you think! And why!

Offline IRobot

  • Full Member
  • ****
  • Posts: 1293
  • Portugal & Germany
  • Liked: 284
  • Likes Given: 255
Re: BO vs SpaceX - development methods
« Reply #22 on: 01/26/2016 09:12 PM »
How much of an advantage does a clean sheet give you?
Depends on perspective. You are only looking at reusability.

BO started with a clean sheet focused on reusability.
SpaceX started with a clean sheet focused on price and reliability, with an eye on reusabilty (as a consequence of price focus).

Why don't you see multiple engine out capability in BO design? (At least on the current design).
Would it be because they narrowed down their focus on reusability?

Why don't you see vertical integration of production as a major objective for BO?

BO might change a lot in the upcoming years, but for now they seem focused on one requirement (reusability) while SpaceX is working on multiple fronts, because there was an excellent requirement analysis in the beginning.

Most projects fail due to bad requirement engineering, not because they don't start with a clean sheet.

Offline sanman

  • Senior Member
  • *****
  • Posts: 4420
  • Liked: 668
  • Likes Given: 8
Re: BO vs SpaceX - development methods
« Reply #23 on: 01/27/2016 02:20 AM »
Why don't you see multiple engine out capability in BO design? (At least on the current design).
Would it be because they narrowed down their focus on reusability?

Is multi-engine-out useful for suborbital when the capsule is separating at apogee anyway?
If engines go out, then you just have a lower suborbital trajectory.
Seems to me that the only reason they need LAS is in case the vehicle catches fire or explodes.

Quote
Why don't you see vertical integration of production as a major objective for BO?

It doesn't seem like they're in a production phase yet - they just have the one prototype vehicle, and aren't making multiple copies of it (yet). Maybe they want to really prove out that vehicle before deciding to make more of it. They don't seem to be iterating-as-they-go (ie. modifying while servicing customers)


Offline abaddon

  • Full Member
  • ****
  • Posts: 1720
  • Liked: 1197
  • Likes Given: 1030
Re: BO vs SpaceX - development methods
« Reply #24 on: 01/27/2016 01:53 PM »
Seems to me that the only reason they need LAS is in case the vehicle catches fire or explodes.
Or if the rocket fails lower than the minimum altitude for separation of the capsule and safe deployment of the parachute...

Offline leaflion

  • Full Member
  • *
  • Posts: 102
  • United States
  • Liked: 52
  • Likes Given: 17
Re: BO vs SpaceX - development methods
« Reply #25 on: 01/27/2016 02:33 PM »
I do like their fin arrangement at the top, I would expect that that can replace grid fins. But that is not a huge difference.

Really? To me the New Shepard fins on the top are the most hack-ish and inelegant part of the design. This is what I expect to change the most for an orbital launcher, as this will really make the interstage structure a challenge if you are going to have a real 2nd stage and payload massing 100+ tons on top of it.

Grid fins are IMO the most elegant and ingenious part of F9 - wraps perfectly around cylinder shape, and provides all the glide control the stage needs for *very little* mass and few moving parts.

I fully expect Blue's orbital LV booster to have fins more in line with F9 rather than a giant ring fin structure with lots of moving parts.

The grid fins were just an afterthought, that's why they added them after they realized they didn't have enough cross-range.  I'm guessing Blue's fin arrangement, with ring fin and fins at top and bottom is aerodynamically stable while being more manueverable than F9.  With no decel or braking burn they have to be right over the pad when they start their landing burn relying completely on aero surfaces.  F9 mainly uses decel burn for this, with corrections by grid fins and braking burn.  So I think you are seeing different re-entry strategies driving different designs.

Grid fins are borrowed from the N-1 BTW.  Not that that really changes anything, although I get the impression a lot of people think spacex invented them.

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 6777
  • Germany
  • Liked: 1801
  • Likes Given: 1807
Re: BO vs SpaceX - development methods
« Reply #26 on: 01/27/2016 02:55 PM »
The grid fins were just an afterthought, that's why they added them after they realized they didn't have enough cross-range.

I very strongly doubt that. The fins were so quickly added that I am certain they were in development for a while, just not ready for the first flight.

Offline abaddon

  • Full Member
  • ****
  • Posts: 1720
  • Liked: 1197
  • Likes Given: 1030
Re: BO vs SpaceX - development methods
« Reply #27 on: 01/27/2016 03:59 PM »
Grid fins are borrowed from the N-1 BTW.
And Souyz, and smart bombs...
Quote
Not that that really changes anything, although I get the impression a lot of people think spacex invented them.
I get the impression that "a lot of people" is more like "maybe one or two".

Offline sublimemarsupial

  • Full Member
  • ***
  • Posts: 386
  • Liked: 258
  • Likes Given: 3
Re: BO vs SpaceX - development methods
« Reply #28 on: 01/27/2016 04:04 PM »
I do like their fin arrangement at the top, I would expect that that can replace grid fins. But that is not a huge difference.

Really? To me the New Shepard fins on the top are the most hack-ish and inelegant part of the design. This is what I expect to change the most for an orbital launcher, as this will really make the interstage structure a challenge if you are going to have a real 2nd stage and payload massing 100+ tons on top of it.

Grid fins are IMO the most elegant and ingenious part of F9 - wraps perfectly around cylinder shape, and provides all the glide control the stage needs for *very little* mass and few moving parts.

I fully expect Blue's orbital LV booster to have fins more in line with F9 rather than a giant ring fin structure with lots of moving parts.

The grid fins were just an afterthought, that's why they added them after they realized they didn't have enough cross-range.  I'm guessing Blue's fin arrangement, with ring fin and fins at top and bottom is aerodynamically stable while being more manueverable than F9.  With no decel or braking burn they have to be right over the pad when they start their landing burn relying completely on aero surfaces.  F9 mainly uses decel burn for this, with corrections by grid fins and braking burn.  So I think you are seeing different re-entry strategies driving different designs.

Grid fins are borrowed from the N-1 BTW.  Not that that really changes anything, although I get the impression a lot of people think spacex invented them.

Blue's crazy fin system won't work when they don't have the luxury of having a mass fraction of 0.7 or worse, its just way too much dry mass. They'll have to go to something more like F9 for their orbital vehicle, even if it is traditional fins rather than grid fins.
« Last Edit: 01/27/2016 04:04 PM by sublimemarsupial »

Offline Space Ghost 1962

  • Senior Member
  • *****
  • Posts: 2783
  • Whatcha gonna do when the Ghost zaps you?
  • Liked: 2907
  • Likes Given: 2249
Re: BO vs SpaceX - development methods
« Reply #29 on: 01/27/2016 04:34 PM »
Ahem.  There's another use of the "crazy fins" at the top of the NS booster.

Consider a Max-Q abort for whatever reason. That apparatus might shed enough aeroload to allow the survival of the booster following such separation. Both booster and capsule might then safely land.

Lack of such for an in-flight abort for the proposed F9/Dragon inflight abort doom's the booster.

Note also the additional drymass needed to accept such aeroloads, not only in the top mechanism that sheds / flow reconnects / maintains control, but the top dome and booster sidewalls.

The only advantage of such would be to allow casual abort for any reason (medical?) while preserving reusability.

If this is the case, as it might be for, say celebrity clientele, then drymass considerations are way, way north of what you all are considering.

Offline Roga

  • Member
  • Posts: 29
  • Liked: 19
  • Likes Given: 11
Re: BO vs SpaceX - development methods
« Reply #30 on: 01/29/2016 04:38 AM »
The difference between NS & Falcon boosters are an excellent teaching tool in the differences between suborbital and orbital flight. For the same reason, they are a poor way to infer the intentions of the designers. It's like saying passenger cars were designed from scratch to travel on roads, while semi trucks are clearly trains that have been adapted for road travel. Sometimes a cigar is just a cigar.


Offline TomTX

  • Member
  • Posts: 53
  • Austin
  • Liked: 25
  • Likes Given: 8
Re: BO vs SpaceX - development methods
« Reply #31 on: 02/12/2016 02:56 PM »
BO can't change the laws of physics.

BO's New Shepard is small, agile, weighs (probably) very little, goes straight up, and back down again.

I'm going to dispute that NS (probably) weighs very little.

F9 can throttle considerably deeper than NS, yet F9 cannot hover due to excess thrust:weight ratio. NS despite higher % thrust at min throttle does a nice little hover dance before landing. That says heavy.

Offline Kabloona

  • Senior Member
  • *****
  • Posts: 4321
  • Velocitas Eradico
  • Fortress of Solitude
  • Liked: 2554
  • Likes Given: 529
Re: BO vs SpaceX - development methods
« Reply #32 on: 02/12/2016 03:19 PM »
F9 can throttle considerably deeper than NS...

Huh? BE-3 can throttle from 110klbf down to 20 klbf. M1D cannot throttle anywhere near that low.

Quote
NS despite higher % thrust at min throttle does a nice little hover dance before landing. That says heavy.

No, it says that NS landing weight could be as low as 20klbf.

By contrast, F9 landing weight is probably in the 60-70klbf range, according to Hans K.

http://forum.nasaspaceflight.com/index.php?topic=36527.msg1361623#msg1361623
« Last Edit: 02/12/2016 03:38 PM by Kabloona »

Offline sublimemarsupial

  • Full Member
  • ***
  • Posts: 386
  • Liked: 258
  • Likes Given: 3
Re: BO vs SpaceX - development methods
« Reply #33 on: 02/12/2016 03:59 PM »

Huh? BE-3 can throttle from 110klbf down to 20 klbf. M1D cannot throttle anywhere near that low.


M1D can't, but F9 as a whole vehicle can, because it can already get to ~11% throttle by only using the center engine instead of all 9. As fraction of total thrust:

NS: 20000/110000 = 18%
F9: (170000*0.7)/(170000*9) = 7%

Which tells you that New Shepards mass fraction is way way worse than F9's if New Shepard can hover while F9 can not even though it can effectively throttle much lower.
« Last Edit: 02/12/2016 04:01 PM by sublimemarsupial »

Offline Kabloona

  • Senior Member
  • *****
  • Posts: 4321
  • Velocitas Eradico
  • Fortress of Solitude
  • Liked: 2554
  • Likes Given: 529
Re: BO vs SpaceX - development methods
« Reply #34 on: 02/12/2016 04:08 PM »

Huh? BE-3 can throttle from 110klbf down to 20 klbf. M1D cannot throttle anywhere near that low.


M1D can't, but F9 as a whole vehicle can, because it can already get to ~11% throttle by only using the center engine instead of all 9. As fraction of total thrust:

NS: 20000/110000 = 18%
F9: (170000*0.7)/(170000*9) = 7%

Which tells you that New Shepards mass fraction is way way worse than F9's if New Shepard can hover while F9 can not even though it can effectively throttle much lower.

I wasn't talking about mass fraction. I was commenting on this statement by TomTX:

Quote
I'm going to dispute that NS (probably) weighs very little.

I guess it depends on your definition of "little," but landing weight could be as low as around 20klbf based on BE-3 throttle lower limit.

If TomTX was talking about mass fraction, that wasn't clear. Kevinof, who made the original statement that NS "weighs very little" was talking about absolute size, not mass fraction.
« Last Edit: 02/12/2016 04:17 PM by Kabloona »

Offline sublimemarsupial

  • Full Member
  • ***
  • Posts: 386
  • Liked: 258
  • Likes Given: 3
Re: BO vs SpaceX - development methods
« Reply #35 on: 02/12/2016 04:09 PM »

Huh? BE-3 can throttle from 110klbf down to 20 klbf. M1D cannot throttle anywhere near that low.


M1D can't, but F9 as a whole vehicle can, because it can already get to ~11% throttle by only using the center engine instead of all 9. As fraction of total thrust:

NS: 20000/110000 = 18%
F9: (170000*0.7)/(170000*9) = 7%

Which tells you that New Shepards mass fraction is way way worse than F9's if New Shepard can hover while F9 can not even though it can effectively throttle much lower.

I wasn't talking about mass fraction. I was pointing out the error of this statement by TomTX:

Quote
I'm going to dispute that NS (probably) weighs very little.

I guess it depends on your definition of "little," but landing weight could be as low as around 20klbf based on BE-3 throttle lower limit.

Its not an error. Relative to its takeoff weight, NS does not weigh very little, speaking in terms of rockets.

Another way to put it - in terms of mass fraction, it is "heavy"
« Last Edit: 02/12/2016 04:12 PM by sublimemarsupial »

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32440
  • Cape Canaveral Spaceport
  • Liked: 11186
  • Likes Given: 331
Re: BO vs SpaceX - development methods
« Reply #36 on: 02/12/2016 04:13 PM »
Its not an error. Relative to its takeoff weight, NS does not weigh very little, speaking in terms of rockets.

takeoff weight has no bearing on matter. 

Offline sublimemarsupial

  • Full Member
  • ***
  • Posts: 386
  • Liked: 258
  • Likes Given: 3
Re: BO vs SpaceX - development methods
« Reply #37 on: 02/12/2016 04:14 PM »
Its not an error. Relative to its takeoff weight, NS does not weigh very little, speaking in terms of rockets.

takeoff weight has no bearing on matter.

Thats the textbook definition of mass fraction. Of course it has bearing on the matter.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32440
  • Cape Canaveral Spaceport
  • Liked: 11186
  • Likes Given: 331
Re: BO vs SpaceX - development methods
« Reply #38 on: 02/12/2016 04:20 PM »

Thats the textbook definition of mass fraction. Of course it has bearing on the matter.


Mass fraction has no bearing on the matter either.  The topic is at landing, not launch and not in flight.  20klb is lighter than 70klb, and hence not "heavy".
« Last Edit: 02/12/2016 04:21 PM by Jim »

Offline Kabloona

  • Senior Member
  • *****
  • Posts: 4321
  • Velocitas Eradico
  • Fortress of Solitude
  • Liked: 2554
  • Likes Given: 529
Re: BO vs SpaceX - development methods
« Reply #39 on: 02/12/2016 04:22 PM »
Its not an error. Relative to its takeoff weight, NS does not weigh very little, speaking in terms of rockets.

takeoff weight has no bearing on matter.

Thats the textbook definition of mass fraction. Of course it has bearing on the matter.

You're dragging me into your discussion of mass fractions, which I'm not disputing.

Kevinof simply stated earlier that NS "weighs very little." Then TomTX argued the point with a mass fraction argument that has only a tangential relevance to Kevinof's observation.

NS does indeed "weigh very little" in comparison to F9, whether fueled or dry.

Tags: