Author Topic: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)  (Read 183029 times)

Online Robotbeat

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #20 on: 10/03/2013 03:18 am »
IMO one week would still be "rapidly".

Expendable orbital launchers have demonstrated sustained weekly turnaround, so its hard to see how reusable turned around in a week would be much of an improvement.
They did that with 50 different airframes a year. If you needed a week-long turnaround for reusable, you could still do a launch every day, you'd just need 7 different airframes (or if one per week, just one or two airframes).

If your launch vehicle lasted at least two years, that's two orders of magnitude reduction in number of airframes required. That's not significant??
« Last Edit: 10/03/2013 03:20 am by Robotbeat »
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Offline beancounter

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #21 on: 10/03/2013 03:50 am »
One of the benefits about shooting for rapid turnaround (which incidentally I don't think SpaceX really needs) is that it makes you question all the steps and actions that you have to take in the process. In questioning these, you can then identify unnecessary steps or improve inefficient ones.  This will have a direct impact on cost as well. 
I really think that's what they're doing not really aiming to do it, just so that it provides the impetus to facilitate improvement.  Of course I could be entirely mistaken.   ;D
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Offline ChrisWilson68

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #22 on: 10/03/2013 04:23 am »
One of the benefits about shooting for rapid turnaround (which incidentally I don't think SpaceX really needs) is that it makes you question all the steps and actions that you have to take in the process. In questioning these, you can then identify unnecessary steps or improve inefficient ones.  This will have a direct impact on cost as well. 
I really think that's what they're doing not really aiming to do it, just so that it provides the impetus to facilitate improvement.  Of course I could be entirely mistaken.   ;D

Time really is money.  If they can do single-digit-hour reuse, it can't help being very cheap.

Online Robotbeat

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #23 on: 10/03/2013 04:30 am »
One of the benefits about shooting for rapid turnaround (which incidentally I don't think SpaceX really needs) is that it makes you question all the steps and actions that you have to take in the process. In questioning these, you can then identify unnecessary steps or improve inefficient ones.  This will have a direct impact on cost as well. 
I really think that's what they're doing not really aiming to do it, just so that it provides the impetus to facilitate improvement.  Of course I could be entirely mistaken.   ;D

Time really is money.  If they can do single-digit-hour reuse, it can't help being very cheap.
...this is incidentally also true of development costs. There is sometimes a trade-off between development costs and operational costs, but if something costs, say, $20 billion in development costs, there's very little chance it will have low operational costs. That's why I tend to think that low-cost RLV development efforts have a greater chance of actually reducing operational costs versus expendable launch vehicles.
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To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline ChrisWilson68

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #24 on: 10/03/2013 04:42 am »
One of the benefits about shooting for rapid turnaround (which incidentally I don't think SpaceX really needs) is that it makes you question all the steps and actions that you have to take in the process. In questioning these, you can then identify unnecessary steps or improve inefficient ones.  This will have a direct impact on cost as well. 
I really think that's what they're doing not really aiming to do it, just so that it provides the impetus to facilitate improvement.  Of course I could be entirely mistaken.   ;D

Time really is money.  If they can do single-digit-hour reuse, it can't help being very cheap.
...this is incidentally also true of development costs. There is sometimes a trade-off between development costs and operational costs, but if something costs, say, $20 billion in development costs, there's very little chance it will have low operational costs. That's why I tend to think that low-cost RLV development efforts have a greater chance of actually reducing operational costs versus expendable launch vehicles.

I think that's a good point.  It's not a perfect correlation, because it's possible to skimp on development costs and end up with higher operating costs because of it.  But if your development costs are very high, then you're building something very complex, and that is very likely to be complex to maintain and operate.

Offline beancounter

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #25 on: 10/03/2013 05:53 am »
One of the benefits about shooting for rapid turnaround (which incidentally I don't think SpaceX really needs) is that it makes you question all the steps and actions that you have to take in the process. In questioning these, you can then identify unnecessary steps or improve inefficient ones.  This will have a direct impact on cost as well. 
I really think that's what they're doing not really aiming to do it, just so that it provides the impetus to facilitate improvement.  Of course I could be entirely mistaken.   ;D

Time really is money.  If they can do single-digit-hour reuse, it can't help being very cheap.
...this is incidentally also true of development costs. There is sometimes a trade-off between development costs and operational costs, but if something costs, say, $20 billion in development costs, there's very little chance it will have low operational costs. That's why I tend to think that low-cost RLV development efforts have a greater chance of actually reducing operational costs versus expendable launch vehicles.

I think that's a good point.  It's not a perfect correlation, because it's possible to skimp on development costs and end up with higher operating costs because of it.  But if your development costs are very high, then you're building something very complex, and that is very likely to be complex to maintain and operate.

Ok good discussion however I'd still like to understand why people think a quick turnaround is required for any SpaceX scenerio.  Does SpaceX require a quick turnaround or is it only about driving improvement and cost reduction?
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Offline aero

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #26 on: 10/03/2013 06:59 am »
Quote
Ok good discussion however I'd still like to understand why people think a quick turnaround is required for any SpaceX scenerio.  Does SpaceX require a quick turnaround or is it only about driving improvement and cost reduction?

I can still only think of the one scenario, that of loading a large number of people aboard a Mars Colony Transport using smaller launch vehicles. Then, since the MTC would be reachable from only the one launch site because of its orbital inclination, they would need to launch in quick succession from that one site. Or lease more launch pads.

People are the only thing I can think of who use up consumables while waiting on orbit, and who are also likely to tell the whole Earth how unhappy the waiting is making them.
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Online LouScheffer

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #27 on: 10/03/2013 10:12 am »
  But if your development costs are very high, then you're building something very complex, and that is very likely to be complex to maintain and operate.

This is not true if the point of development is explicitly to make something easy to maintain and operate.  Look at a tablet or a cell phone; these things are hideously complex, and expensive to develop, but require no maintenance and minimal training. 

Offline Silmfeanor

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #28 on: 10/03/2013 10:23 am »
  But if your development costs are very high, then you're building something very complex, and that is very likely to be complex to maintain and operate.

This is not true if the point of development is explicitly to make something easy to maintain and operate.  Look at a tablet or a cell phone; these things are hideously complex, and expensive to develop, but require no maintenance and minimal training.

They don't have any moving parts either, or go through any sort of heavy environmental changes, or come in contact with LoX.

There is a fundamental difference.

Online LouScheffer

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #29 on: 10/03/2013 11:21 am »
  But if your development costs are very high, then you're building something very complex, and that is very likely to be complex to maintain and operate.

This is not true if the point of development is explicitly to make something easy to maintain and operate.  Look at a tablet or a cell phone; these things are hideously complex, and expensive to develop, but require no maintenance and minimal training.

They don't have any moving parts either, or go through any sort of heavy environmental changes, or come in contact with LoX.

There is a fundamental difference.
Sure, this was just an example showing design cost and complexity does not necessarily imply high maintenance.  But some of this was due to deliberately investing in technologies, such as ICs, that can be hard to make but low maintenance thereafter.

Look at the cars of today vs 50 years ago for a mechanical example.  They are much more complex, and more expensive to design, but in operation they require much less maintenance, have higher performance, and are easier to use.

Offline Lurker Steve

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #30 on: 10/03/2013 12:26 pm »
  But if your development costs are very high, then you're building something very complex, and that is very likely to be complex to maintain and operate.

This is not true if the point of development is explicitly to make something easy to maintain and operate.  Look at a tablet or a cell phone; these things are hideously complex, and expensive to develop, but require no maintenance and minimal training.

Actually, the only maintenance you can do on a tablet or cell phone is drop it in the recycling bucket at your local Best Buy. They aren't any more reliable, there just aren't any replaceable parts. Apple doesn't even want you to replace a simple item like a battery any longer. If you drop the phone and break the glass, you basically just bought a new/refurbished phone.

Your example with automobiles is also incorrect. Auto makers / dealers know that the repair shop is a significant revenue center for them. Nothing can be diagnosed / replaced without special tools. Cars were much easier to maintain / repair 20-30 years ago. The wear items haven't changed, and they still need to be replaced at the same frequency. It is just more expensive now, and the manufacturers are trying to get rid of the DIY guys.

Online LouScheffer

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #31 on: 10/03/2013 01:06 pm »

Your example with automobiles is also incorrect. [...] The wear items haven't changed, and they still need to be replaced at the same frequency. It is just more expensive now, and the manufacturers are trying to get rid of the DIY guys.

I don't think this is true.  When's the last time you tested the compression and changed your rings?  This used to be common.   How about re-grinding your valves, then shimming them to correct clearances?  Lubricating your u-joints?(this used to be every 1500 miles)    Brakes last longer than they did, and you don't need to adjust them (they are self adjusting).   Tires last much longer, too.  Even changing your oil has decreased for every 2500 miles to every 7500.  I'd guess overall the wear items last 3x longer than they did in the 1960s.  Cost, over the life of the car, assuming all maintenance is done by professionals, would be an interesting comparison...

Offline Jim

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #32 on: 10/03/2013 01:19 pm »

I don't think this is true.  When's the last time you tested the compression and changed your rings?  This used to be common.   How about re-grinding your valves, then shimming them to correct clearances?  Lubricating your u-joints?(this used to be every 1500 miles)    Brakes last longer than they did, and you don't need to adjust them (they are self adjusting).   Tires last much longer, too.  Even changing your oil has decreased for every 2500 miles to every 7500.  I'd guess overall the wear items last 3x longer than they did in the 1960s.  Cost, over the life of the car, assuming all maintenance is done by professionals, would be an interesting comparison...

Those items were replaced by CV joints, timing belts, water pumps, navigation system updates,etc.  The same maintenance costs are still there, just on different and more expensive items. 

Offline Jim

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #33 on: 10/03/2013 01:20 pm »
    Quote from: LouScheffer on October 01, 2013, 10:55:57 PM

1,  I didn't say they don't worry.   What I said is much stronger - they DO worry, they have analyzed the problem (see b below), they concluded it was not a serious problem, and they have experimental evidence to prove it.

2. An interesting assertion - every planner guide quotes a typical GTO mission.   The Atlas V guide says, for example, "The short-coast mission is the standard mission design for GTO launches".  Now of course this is just a template, and every launch will differ in the fine details, but for this argument you can substitute "any launch where the second upper-stage burn occurs at low altitude".  There are many such launches, as this is the usual way to launch GTO missions from Florida.

3.  This is wrong on two counts.  It is very relevant, and it's certainly possible, and probably mandatory, to analyze the effects should a second stage explode during operation.
Quote

4. Wrong again - look up the definition of a hypervelocity collision, where the kinetic energy of the collision exceeds the chemical energy of the constituents.  One kg of hydrogen/oxygen can release 27 MJ.  This is the energy of the same one kg travelling at 5.2 km/sec.  For the ASAT test above, the closing velocity was more than 10 km/sec; for the Iridium/Kosmos collision, the closing speed was 11.7 km/sec.  So a worst case explosion has much less energy than a worst case collision.  In terms of the material, the satellite itself is the same as might be involved in a collision.  Most of the rest of the mass is tanks, which are large and light and will decay out of orbit very quickly.

5.  Common sense isn't.


Let's count the ways that the above is wrong.

1.  USA-193 was a specific event with a spacecraft and not applicable to other scenarios.   The military analyzed one problem.  It is no where close the same thing

2.   Still doesn't account for GTO missions with more than 2 burns.  Also, the second burn may occur at a low altitude but the apogee is higher.

3.  Wrong again on both accounts.  It is not anywhere close to the same, there are many difference.  And, no, not only are potential explosions are not analyzed, it is almost impossible to do it because of the variation.    Why do you post things that you know nothing about.

4.  a.  Wrong again.  There are elements of launch vehicle and spacecraft that could self propel such as prop and pressure tanks.   The launch vehicle will break up will have larger intact pieces than a collision.
b.  No, the launch vehicle has denser hardware such as the engine, the thrust section, the payload adapter, etc

5.   Common sense is not on your side, here and other places.  The risks and consequences of breakup due to a bad engine start out weigh any benefits in trying to complete the mission.
« Last Edit: 10/03/2013 01:41 pm by Jim »

Offline cambrianera

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #34 on: 10/03/2013 01:31 pm »
Actually, the only maintenance you can do on a tablet or cell phone is drop it in the recycling bucket at your local Best Buy.

False, I've personally disassembled and reassembled some of my cell phones.
Easy internet guides are available http://www.ifixit.com/Device/Samsung_Galaxy_S_III and also spare parts.

They aren't any more reliable, there just aren't any replaceable parts. Apple doesn't even want you to replace a simple item like a battery any longer. If you drop the phone and break the glass, you basically just bought a new/refurbished phone.
False, reliability is up; cell phones resurrected the gorilla glass (oooold invention, never fully utilized) yust to improve reliability. About non replaceability, that's what Lou said; if you don't want, no maintenance is needed.

Your example with automobiles is also incorrect. Auto makers / dealers know that the repair shop is a significant revenue center for them. Nothing can be diagnosed / replaced without special tools.
Then? Manufacturers with bad performance on reliability or maintenance/repair costs regularly hit the dust

Cars were much easier to maintain / repair 20-30 years ago.
False, never been so easy to mantain/repair; as to DIY possibilities that was at least 30-40 years ago.

The wear items haven't changed, and they still need to be replaced at the same frequency.
False, ie I was used to replace myself spark plugs every 15000 km, now after 100000 km they are spotless.

It is just more expensive now, and the manufacturers are trying to get rid of the DIY guys.
Depending on manufacturers, some yes, some not

All in all, your observations about what LouScheffer said are meaningless (and OT).
What is important is that SpaceX is designing rockets in a different way, looking less at performance and more at cost, with a drive for continuous improvement that is common in consumer design and production, uncommon in aerospace.
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Offline Lurker Steve

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #35 on: 10/03/2013 01:41 pm »

I don't think this is true.  When's the last time you tested the compression and changed your rings?  This used to be common.   How about re-grinding your valves, then shimming them to correct clearances?  Lubricating your u-joints?(this used to be every 1500 miles)    Brakes last longer than they did, and you don't need to adjust them (they are self adjusting).   Tires last much longer, too.  Even changing your oil has decreased for every 2500 miles to every 7500.  I'd guess overall the wear items last 3x longer than they did in the 1960s.  Cost, over the life of the car, assuming all maintenance is done by professionals, would be an interesting comparison...

Those items were replaced by CV joints, timing belts, water pumps, navigation system updates,etc.  The same maintenance costs are still there, just on different and more expensive items.

It was a common maintenance item to have to replace and properly set the gap and timing on the points in the distributor, but that is nothing compared to the cost of having to replace the "computer" on a modern car's electronic ignition. Also, more modern cars have aluminum heads, which are more prone to warp if the car overheats, leading to an expensive head gasket replacement (and all that value work at the machine shop). I have a 328i in my driveway as evidence. You can't really do a proper brake job anymore, since the factory rotors are too thin, and they didn't leave enough metal to machine them down, Hence the rotors need to be replaced each and every brake job.

Offline Jim

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #36 on: 10/03/2013 01:49 pm »
improvement that is common in consumer design and production, uncommon in aerospace.

That is untrue.   Look at every launch vehicle.  The Atlas V's and Delta IV's that are flying now are not the same as the ones that first flew.  The fact that Atlas V hasn't done a V1 to V1.1 (aside from the re-usability items) means that LM properly selected the engine and tanks sizes in the first place.  But that didn't mean they haven't done upgrades.  There was new avionics, new interstage adapters, helium tanks, etc.

Delta IV upgraded its engine. 

Offline cambrianera

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #37 on: 10/03/2013 01:58 pm »
improvement that is common in consumer design and production, uncommon in aerospace.

That is untrue.   Look at every launch vehicle.  The Atlas V's and Delta IV's that are flying now are not the same as the ones that first flew.  The fact that Atlas V hasn't done a V1 to V1.1 (aside from the re-usability items) means that LM properly selected the engine and tanks sizes in the first place.  But that didn't mean they haven't done upgrades.  There was new avionics, new interstage adapters, helium tanks, etc.

Delta IV upgraded its engine.

Why you quoted cutting away that purposedly underlined word?
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Offline R7

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #38 on: 10/03/2013 02:12 pm »
Why you quoted cutting away that purposedly underlined word?

Continuous improvements appear to cause continuous shifting to the right, so is it given that aerospace customers really appreciate that? Continuous service, ah that would be something.
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Offline cambrianera

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Re: SpaceX Falcon 9 v1.1 DISCUSSION AND UPDATES (THREAD 4)
« Reply #39 on: 10/03/2013 02:20 pm »
Why you quoted cutting away that purposedly underlined word?

Continuous improvements appear to cause continuous shifting to the right, so is it given that aerospace customers really appreciate that? Continuous service, ah that would be something.

Found the word? Good....
And agree on service, because I never said SpaceX is better, only time will tell; what I said is they are different.......
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