Tankers. A new price category?

[charliem]

I have an idea and a question about its feasibility. I'm no space engineer, nor knowledgeable enough in this field to develop an answer, so I'd like to ask it here.

In a mission to the Moon about 3/4 of the mass lifted to LEO is fuel. Going to GEO the ratio is not that much better, and going as far a Mars is even worse.

To date we can classify launch vehicles in two categories by price: very expensive (for cargo) and extremely expensive (for humans).

When the cargo value is in the same range as the vehicle (or above) is sensible to make it as reliable as possible, and that implies cost, but lately we've been toying with the idea of fuel depots in orbit, and fuel is cheap, almost dirt cheap (and food, air, and other human consumables are not much more expensive).

Paying $200 M to deliver to LEO 20 mt of cargo which value is less than $200.000 looks plain dumb unless there's no other way.

Is there?

If we could determine a function for rate of success vs cost, and accepting cargo value is negligible against launcher value, should be possible to calculate the sweet spot where we can get the most mass in orbit for the least money.

Complex engines? Triple redundant avionics? 40% structural margins? Reusable hardware? Extensive monitoring? ... How much of that could we rub off?

So, summing up, my question is: How much could the cost of a launch vehicle be taken down if we accepted a significant decrease in its reliability? (how about 80% or 90%, 1 or 2 losses in every 10 launches?)

P.D. This post was inspired by the Mobile Hab for Mars exploration thread: http://forum.nasaspaceflight.com/index.php?PHPSESSID=2a77e4ff1052dcde92a028a415de5e02&topic=17360.msg417425#msg417425

[savuporo]

You probably want to read up on MCD ( minimum cost design ) ideas for space launch.
These tend to go towards ablative nozzles, pressure fed or low-cost pump designs ( piston pumps, flometrics style pistonless pumps) etc.

MicroCosm has been the recent proponent of the concept, with their Scorpius launcher plans.

Of course, they are always two years away from their first launch as many others.

[deltaV]

A malfunctioning fuel tanker rocket puts innocent buildings, satellites and people at risk, not just the fuel. A disabled tanker in orbit could explode from overpressure, scattering debris that put other spacecraft at risk. A malfunctioning navigation system could cause the rocket to shoot for the stars but hit London instead. Liquid oxygen is cheap but a worker killed in a liquid oxygen fueled fire is not. A cheap payload allows one to cut some corners, but many of the most expensive corners can't be cut.

That said a lot of people (myself included) guess that if there were a reliable market for propellant in orbit someone would find a way to provide it cheaper than current launchers.

[Jim]

A malfunctioning fuel tanker rocket puts innocent buildings, satellites and people at risk, not just the fuel. A disabled tanker in orbit could explode from overpressure, scattering debris that put other spacecraft at risk. A malfunctioning navigation system could cause the rocket to shoot for the stars but hit London instead. Liquid oxygen is cheap but a worker killed in a liquid oxygen fueled fire is not. A cheap payload allows one to cut some corners, but many of the most expensive corners can't be cut.

That said a lot of people (myself included) guess that if there were a reliable market for propellant in orbit someone would find a way to provide it cheaper than current launchers.

No, you don't understand the concept.  It is not a cheaper payload, but cheaper launch vehicle.  Also, the cheaper  launch vehicles aren't blowing up left and right.  They are just simpler.

[charliem]

A malfunctioning fuel tanker rocket puts innocent buildings, satellites and people at risk, not just the fuel. ... A cheap payload allows one to cut some corners, but many of the most expensive corners can't be cut.

Alright, some corners can't be cut, but most? ... I bet some could, and wonder how much doing those'd reduce the price tag.

Of course we are not talking about launching from Oklahoma, and of course you can't dispose of the Range Safety System, but what about triple avionics? Why not just one and accept some loss once in a while?

And why a 40% margin on structure, why not 15%?

Does anyone know which systems take the lion share in a MLV? For example in a Falcon 9 (they are less secretive than others), how much goes to the engines, avionics, tanks, piping, structure, quality control, overhead, recovering hardware, tracking, etc.

If engines were the most expensive part, how much could the cost of a Merlin be reduced if they did a disposable version?

If every risk were unacceptable no ship would ever fly.

[RocketmanUS]

If not mistaken margin for cargo is 1.2 and crew is 1.4

High flight rates for RLV's or disposable would lower per launch costs. So the tanker and cargo launchers should be the same to have higher flight rates.

For Atlas the RD-180 was said to be around $10M each and the launch of the smaller version of Atlas V was around $138M

[go4mars]

No, you don't understand the concept.  It is not a cheaper payload, but cheaper launch vehicle.  Also, the cheaper  launch vehicles aren't blowing up left and right.  They are just simpler.

What important design choices make a launch vehicle simpler/cheaper? 

[savuporo]

What important design choices make a launch vehicle simpler/cheaper? 

Propellant type, pump type ( or pressure fed). These are the primary variables.

EDIT: Number of stages, obviously. The size of the rocket. Beyond a certain size, it gets very expensive due to ground infrastructure requirements.

And its all driven launch rate ultimately anyways.  No rocket flying once a year is going to be cheap.

[kkattula]

What important design choices make a launch vehicle simpler/cheaper? 

Higher structural margin, alowing cheaper materials and manufacturing techniques.

Lower payload fraction. Burns more fuel per mass payload, but fuel is usually very cheap.

[pathfinder_01]

What important design choices make a launch vehicle simpler/cheaper? 

Higher structural margin, alowing cheaper materials and manufacturing techniques.

Lower payload fraction. Burns more fuel per mass payload, but fuel is usually very cheap.

and less labor needed to launch.

[Ben the Space Brit]

I must admit that when I think 'tanker', I am thinking more 'robot in-flight refuelling vehicle'; something like a Cygnus or ATV with pumping equipment so it can refuel an upper stage in orbit.  That would require a degree of engineering and ground checks before launch.

However, it occurs to me that, if we go down the depot route, all you really need is a payload tank attached to an instrumentation, power and propulsion unit like the ATV or Cygnus SM.  The pumping equipment will be on the depot platform.  The IFR version would only be needed to support a vehicle that, for whatever reason (most probably launch inclination) would not be able to rendezvous with a depot platform.

[kevin-rf]

and less labor needed to launch.

Ding Ding Ding we have the Winner!

The standing army is the real cost driver. The only way to drive cost down is to use less people, or fly more often with the same number people. The only other option is to only hire interns

[edkyle99]

If we could determine a function for rate of success vs cost, and accepting cargo value is negligible against launcher value, should be possible to calculate the sweet spot where we can get the most mass in orbit for the least money.

The answer depends on how much propellent is needed and for how many years.  The propellant delivery rate.

A limiting factor would be the cost of the missions that would use the propellant!  The propellant could be free to its users but the missions themselves (lunar or Mars landings, say) could still cost too much to fly very often.  As a result, the total propellant delivery rate will likely be too low to support development of super-monster rockets, which would be the most cost effective way to launch heavy payloads but only if they could fly constantly and fairly frequently. 

For most purposes, then, the cheapest way to deliver propellant would be to skip the high cost of rocket development and simply use existing rockets - preferably lots of them.  Their per-unit costs should decline as their flight rate increases. 

 - Ed Kyle

[douglas100]

Ding Ding Ding we have the Winner!

The standing army is the real cost driver. The only way to drive cost down is to use less people, or fly more often with the same number people. The only other option is to only hire interns

Or buy your launch from a country with lower wage rates. What? It's already happened?

[mmeijeri]

MicroCosm has been the recent proponent of the concept, with their Scorpius launcher plans.

Space Systems/Loral's Aquarius Launch Vehicle concept is another example. I'm not sure Microcosm's launchers are intended to be unreliable, I think they're merely simple and well-suited to mass-production. They're similar to Sea Dragon in that respect, though obviously very small instead of enormous.

Sea Dragon: simple and huge
Scorpius: small, simple, mass-produced
Aquarius: small, simple, mass-produced, unreliable

[wolfpack]

Private space companies SpaceX and Blue Origin seem to think that recovering the LV is the best way to reduce cost. Not dropping millions of dollars worth of hardware into the ocean is the best way to save millions of dollars!

[mmeijeri]

That's certainly true for precious cargo, like aerospace hardware or humans. But for bulk materials it's not inconceivable that mass produced, unreliable and expendable launchers would turn out to be cheaper. Given a market for selling propellant in orbit the market would discover what the most economical approach was.

[edkyle99]

That's certainly true for precious cargo, like aerospace hardware or humans. But for bulk materials it's not inconceivable that mass produced, unreliable and expendable launchers would turn out to be cheaper. Given a market for selling propellant in orbit the market would discover what the most economical approach was.

Why plan to build "unreliable" launchers?  I'm not sure how making a launch vehicle less reliable would save money.  I'm not even sure how to save money by making a launch vehicle less reliable! 

 - Ed Kyle

[mmeijeri]

Why plan to build "unreliable" launchers?  I'm not sure how making a launch vehicle less reliable would save money.  I'm not even sure how to save money by making a launch vehicle less reliable! 

The Aquarius plan is to use a very simple single stage vehicle with very small margins, small enough that your vehicle can make it to orbit, but so small that one in three times it won't.

[sdsds]

I'm interested in the assertions about labor costs.

The trick for tankers will be to examine the flow of vehicles (reusable or expended) through the system and minimize the (mostly labor) costs to maintain that flow.  Personally I would target a system that launches every two weeks, where the staff for pad and control room operations consisted of only 10 workers and 4 managers working 40 hour work weeks.  Factor in on-going training, plus vacation and unplanned sick leave, and keeping a reliable launch tempo.  The result would need to be a fairly lean operation, with plentiful automation but also a fair amount of cross-training between positions.

I believe for the most part those workers need a bachelor's degree or equivalent and would expect around $90k in salary on average.  The overhead costs to employ them would likely double that, 14 * 90 * 2 ~= $2.5m per year.  If they performed 50 launches, that would be $50k per launch.

Is that estimate (a) reasonable; (b) off by a factor of 2 or more; (c) off by a factor of 10 or more?

[pathfinder_01]

I'm interested in the assertions about labor costs.

The trick for tankers will be to examine the flow of vehicles (reusable or expended) through the system and minimize the (mostly labor) costs to maintain that flow.  Personally I would target a system that launches every two weeks, where the staff for pad and control room operations consisted of only 10 workers and 4 managers working 40 hour work weeks. 

Another way and the best way in the short term is to use a rocket that has other users/uses. Say Atlas, Detla, Falcon 9, ect.  That way you don't need to build pads, ect.

For instance a propellant verions of Dragon or more likely Cgynus. Only trouble is that in the case of Cgynus the most it could deilver would be about 3 tons or so(enough for a SEP system maybe).

[Cherokee43v6]

Why talk about converting Cygnus or Dragon or building a dedicated tanker craft.

Why not come up with an RCS and a multiple restart system for the second stage on an F-9 or Taurus2 and stretch the tanks?  Instead of a payload, the nose fairing would cover a docking mechanism.  You would save weight all around, thus maximizing propellant delivered.  Right?

[douglas100]

In other words, the ACES approach (but not necessarily with cryogenic propellants.)

[pathfinder_01]

Why talk about converting Cygnus or Dragon or building a dedicated tanker craft.

Why not come up with an RCS and a multiple restart system for the second stage on an F-9 or Taurus2 and stretch the tanks?  Instead of a payload, the nose fairing would cover a docking mechanism.  You would save weight all around, thus maximizing propellant delivered.  Right?

Depends on what propellant you plan to use. Taurus II 2nd stage is solid. F9 uses Lox/Kerosene. While LoX/kerosene is a possible propellant for a depot so are Lox/methane, lox/Loh, Aragon, Xenon, Hydrizine and lots of others.

[sdsds]

the best way in the short term is to use a rocket that has other users/uses. Say Atlas, Detla, Falcon 9

Yes but none of those launch systems are willing to tolerate the loss of a vehicle.  So for any payload including a tanker they must charge at least the marginal cost of a fully reliable launch.  That eliminates the "new price category" premise of this thread.

[douglas100]

Something along the lines of the Beal BA 2 might be feasible. Fairly low tech but with a reasonable payload to LEO. All of this is dependent on a viable market emerging, of course.

[savuporo]

Why plan to build "unreliable" launchers?  I'm not sure how making a launch vehicle less reliable would save money.  I'm not even sure how to save money by making a launch vehicle less reliable! 

..really ? You could make any launch vehicle in existence today much cheaper by simply removing half of the people working on it, and skipping a ton of procedures ( not testing, verifying, or checklisting any bit of hw that goes on a rocket )

However, your reliability vs cost curve is going to hit a very bad spot, as the launch vehicles have not been designed for that.

If you design from the outset for mass manufacturing, regular mass manufacturing QA methods, low personnel overhead costs you could, in theory, have a rocket that starts out being 80% reliable and improves as you improve your manufacturing process.

That, by the way, is how a lot of new consumer tech enters the market. The yields on the first generation products are often crap.

WRT rockets, there is a historical precedent : V2 started out very unreliable, but they did improve it later on.

[charliem]

Why plan to build "unreliable" launchers?  I'm not sure how making a launch vehicle less reliable would save money.

It's not so much planning "unreliable" as not going the extra mile to maximize reliability.

If to increase it from, lets say, 80% to 98%, you have to double the price, that only makes economic sense when there are other costs beyond the launcher.

With 80% you get 80 payloads up for a cost of 100. Average cost 1.25

With 98% you get 98 payloads up for a cost of 200. Average cost 2.04

[edkyle99]

You could make any launch vehicle in existence today much cheaper by simply removing half of the people working on it, and skipping a ton of procedures ( not testing, verifying, or checklisting any bit of hw that goes on a rocket )

However, your reliability vs cost curve is going to hit a very bad spot, as the launch vehicles have not been designed for that.

If you design from the outset for mass manufacturing, regular mass manufacturing QA methods, low personnel overhead costs you could, in theory, have a rocket that starts out being 80% reliable and improves as you improve your manufacturing process.

I'm not sure I buy into this theory, at least not precisely as described.  In practice, any real rocket that proves unreliable, and by unreliable I mean 80% or less after a few launches, is quickly dropped from service.  Consider, for example, Altas Able, Juno's I and II, Vanguard, Europa, H-II, Delta III, Falcon 1, and soon probably Taurus.  Why not design the rocket to succeed from the outset?   

 - Ed Kyle

[93143]

Private space companies SpaceX and Blue Origin seem to think that recovering the LV is the best way to reduce cost. Not dropping millions of dollars worth of hardware into the ocean is the best way to save millions of dollars!

Sea Dragon was fully reusable, despite dropping into the ocean.  Nothing fancy, just built like a battleship...  and equipped with an inflatable drag enhancer on the tail...  Independent studies indicated extremely low cost to orbit.

[sdsds]

Why not design the rocket to succeed from the outset?   

I think the idea is to design a rocket that succeeds every time, on paper.  When fielded, though, the real-world manufacturing, assembly and launch processes might "fail" occasionally.  That is, they might let through an article that fails to meet its specification or that is exposed to environments outside what it is specified to tolerate.

Just one tiny example:  how many high altitude weather balloons are needed to give 99% confidence the flight will get through any wind shear, vs. the number of balloons needed to give 95% confidence of that?  (I suspect the number of balloons needed for 95% confidence is zero!)

[savuporo]

In practice, any real rocket that proves unreliable, and by unreliable I mean 80% or less after a few launches, is quickly dropped from service.  Consider, for example, Altas Able, Juno's I and II, Vanguard, Europa, H-II, Delta III, Falcon 1, and soon probably Taurus

All examples of rockets not following minimum cost design principles, and thus when working unreliably, hitting a really bad spot in cost vs reliability curve.
So in context of this discussion, really worthless.

[baldusi]

Why plan to build "unreliable" launchers?  I'm not sure how making a launch vehicle less reliable would save money.

It's not so much planning "unreliable" as not going the extra mile to maximize reliability.

If to increase it from, lets say, 80% to 98%, you have to double the price, that only makes economic sense when there are other costs beyond the launcher.

With 80% you get 80 payloads up for a cost of 100. Average cost 1.25

With 98% you get 98 payloads up for a cost of 200. Average cost 2.04

Now do your numbers again considering that the launch cost is just 20% of the whole mission cost.

[Jim]

(I suspect the number of balloons needed for 95% confidence is zero!)

Nope, it is in the 70's

[pippin]

Private space companies SpaceX and Blue Origin seem to think that recovering the LV is the best way to reduce cost. Not dropping millions of dollars worth of hardware into the ocean is the best way to save millions of dollars!

Sea Dragon was fully reusable, despite dropping into the ocean.  Nothing fancy, just built like a battleship...  and equipped with an inflatable drag enhancer on the tail...  Independent studies indicated extremely low cost to orbit.

Paper rockets have a habit of having extremely low cost to orbit, ESPECIALLY with "independent" studies which are usually made by consultants who don't actually have to fly the thing.

[pippin]

All examples of rockets not following minimum cost design principles

SpaceX would disagree.

From looking how all projects trying to reduce cost through what is deemed to be good practice in design-to-cost, I suspect that it's not as simple as it sounds to make a minimum cost design rocket.

I believe the problem is that margins have to already be very, very low to make it to orbit at all (or the rocket has to be really, really large which incurs i's own expenses) which kill a lot of your design-to-cost strategies, especially all these which try to eliminate processes for QA and testing  through e.g. standardization.
I've only followed it more closely with SpaceX but you could clearly see that while getting to actually launch they learned a lot about the weaknesses of their original KISS approach, from ablative nozzles, over pintle injectors, simple tanks without slosh baffles, in-the-loop control and simple staging to corroded nuts...

[charliem]

Why plan to build "unreliable" launchers?  I'm not sure how making a launch vehicle less reliable would save money.

If to increase it from, lets say, 80% to 98%, you have to double the price, that only makes economic sense when there are other costs beyond the launcher.

Now do your numbers again considering that the launch cost is just 20% of the whole mission cost.

Should we renounce to decrease that 20% to, say, 10%, just because it's too little?

To thrive in space we need find ways of cheapen every aspect of our missions, launch costs included.

I saw the first human step on the Moon live when I was a child. I'd very much like to see the first human step on Mars before I pass away. To achieve that we need: 1) A lot more money that we can afford right now, or 2) A much cheaper way to go there.

[edkyle99]

In practice, any real rocket that proves unreliable, and by unreliable I mean 80% or less after a few launches, is quickly dropped from service.  Consider, for example, Altas Able, Juno's I and II, Vanguard, Europa, H-II, Delta III, Falcon 1, and soon probably Taurus

All examples of rockets not following minimum cost design principles, and thus when working unreliably, hitting a really bad spot in cost vs reliability curve.
So in context of this discussion, really worthless.

"Minimum cost design", if you are talking about the classic "Big Dumb Booster" idea, has never been employed.  There are several reasons.  One reason is because the payloads cost more than the rocket - sometimes multiple times more than the rocket.  The Dumb rocket might be able to tolerate an above-average failure rate, but the payloads cannot.  Even if the payloads are propellant tankers, they still have great value in the context of a complex, costly mission buildup sequence.

Rather than developing a BDR, just fly Atlas 15 times per year instead of 5, year after year for decades.  The per-launch cost would drop by one-third or one-half, probably, and 98 percent of the payloads would get where they're supposed to go.

 - Ed Kyle

[baldusi]

You could get a lot better economics if you could slash the costs of transponders, avionics, thrusters, satellite buses, integration and testing. Let's put for example the WGS satellites. Those are fully developed, the factory is working, so an additional unit is almost pure cost. Yet, the participating countries have to spend over USD500 on each bird, plus LV. And then they will have to operate it. So the LV is about 20% or less of the project cost. If you have to add development it's closer to a 5%. So unless you can find a way to radically lower the cost of the mission, a LV that was free would mean a 20% discount. Interesting, but nothing that would explode a new industry.

[pippin]

Well, at _that_ extreme the assumption is obviously wrong. If a flight was close enough to free there are a lot of things _I_ would want to launch so there would indeed be a new industry exploding.
It's a bit of a chicken-and-egg: If you are at 200 M$ a shot you will only develop payloads that are worth that investment and if they should really pay offf they will likely be more expensive and so on...

The point is that I doubt that built-to-cost really gets you there, I don't think current rocket engineers are that dumb to let go for a massive cost reduction potential and while it may give you some savings to let go on reliability a bit I suspect that it will require more than that for _massive_ reductions.

It's just a feeling but I believe the real potential might lie in mass production as Ed writes - after all we've seen it when LVs were ICBMs and if you _know_ you have a case for massive mass-production you might also be able to get some economies of scale by investing in more scalable production facilities, do more automation and all these things that make planes and card affordable.

[93143]

Sea Dragon was fully reusable, despite dropping into the ocean.  Nothing fancy, just built like a battleship...  and equipped with an inflatable drag enhancer on the tail...  Independent studies indicated extremely low cost to orbit.

Paper rockets have a habit of having extremely low cost to orbit, ESPECIALLY with "independent" studies which are usually made by consultants who don't actually have to fly the thing.

Do you actually know anything about Sea Dragon, or are you just shooting from the hip?

I'm not in this for an argument; I just don't like getting hit with derisive generalizations from people who usually turn out to be posturing without data.

[93143]

Well, at _that_ extreme the assumption is obviously wrong. If a flight was close enough to free there are a lot of things _I_ would want to launch so there would indeed be a new industry exploding.

http://forum.nasaspaceflight.com/index.php?topic=21867.msg608276#msg608276

It's just a feeling but I believe the real potential might lie in mass production as Ed writes - after all we've seen it when LVs were ICBMs and if you _know_ you have a case for massive mass-production you might also be able to get some economies of scale by investing in more scalable production facilities, do more automation and all these things that make planes and card affordable.

Planes are about as expensive as rockets.

[mmeijeri]

Planes are about as expensive as rockets.

But you don't throw them away after a single use.

[Jason1701]

Planes are about as expensive as rockets.

But you don't throw them away after a single use.

Exactly, that's why we need a RLV.

[pippin]

Do you actually know anything about Sea Dragon, or are you just shooting from the hip?

Yes. And it's full of assumptions that are nice on paper but have never been even remotely tested. A lot of concepts look very good at that stage.
The biggest issue with SeaDragon is that it relies on a very low margin and tries to compensate this with massive scaling but this can go down the drain very fast if your margin doesn't come by.

[pippin]

Planes are about as expensive as rockets.

Depends on the plane.

But seriously: what's your point? An expensive plane can be profitable and an expensive rocket can be profitable, too. The point is that are a few dozen times more of them being built every year even though you don't throw them away after each use.

[93143]

That's the point.  You don't throw them away after each use.

You can get some economies of scale through mass production, but it's not going to bridge the cost gap between air travel and space travel by itself.

It's not necessarily just about reuse either - I read an interesting essay on launch costs recently in which the author decided that the lack of intact abort modes at all flight stages was a major cost driver.

[RanulfC]

Why plan to build "unreliable" launchers?  I'm not sure how making a launch vehicle less reliable would save money.  I'm not even sure how to save money by making a launch vehicle less reliable! 

If you design from the outset for mass manufacturing, regular mass manufacturing QA methods, low personnel overhead costs you could, in theory, have a rocket that starts out being 80% reliable and improves as you improve your manufacturing process.

That, by the way, is how a lot of new consumer tech enters the market. The yields on the first generation products are often crap.

As an FYI/Example; First Gen Plasma TVs had around a 50% manufacturing "failure" rate or higher and was "acceptable" at that time. Today's rate is less than 10% IIRC the last figure correctly and that's considered "quite-high" in the industry.

WRT rockets, there is a historical precedent : V2 started out very unreliable, but they did improve it later on.

Relevent article:
1993: "A Rocket A Day, Keeps High Costs Away"
http://www.fourmilab.ch/documents/rocketaday.html

Randy

[RanulfC]

Rather than developing a BDR, just fly Atlas 15 times per year instead of 5, year after year for decades.  The per-launch cost would drop by one-third or one-half, probably, and 98 percent of the payloads would get where they're supposed to go.
 - Ed Kyle

Careful Ed, "generalizations" have a habit of coming back on you

Increased manufacturing rates do NOT always maintain reliability rates and tripling the amount of Atlas CCBs built WILL introduce, (even encourage if you will) lower reliability overall. Increased workload, less time available for QA, increased pacing of assembly, check-out, and operations tempo will all contribute and you'll of course actually have to increase personnel for both manufacturing and operations which introduces training errors, management errors and other "personnel" problems that have been "reduced" under the current methods of operation.

Enough to cause the Atlas to suddenly be "unreliable"? Probably not, but it WILL lower your "98%" success assumption.

Randy

[pippin]

That's the point.  You don't throw them away after each use.

You have no proof for that, it's just your personal assumption. Do you have data?

So far, re-usability did not help getting costs down and again - rocket makers are not dumb.

Rockets are not the only example of high-value assets that get thrown away after a single use. There are other cases (e.g. in construction, manufacturing etc.) where perfectly fine equipment gets thrown away because it would be more expensive to refurbish it and to guarantee the quality you need with a second use or where you simply build something new instead of using something that exists just because it's cheaper.

A very different but hands-on example is that it's generally cheaper to tear down an old house and build a new one than to refurbish an old one and that's ESPECIALLY true for cost-optimized buildings like storages, factories etc.

Processes usually make for a bigger part of system costs than most people believe at first glance, _especially_ if you have high quality requirements due to low margins.
It can be much, much cheaper to build a new engine in mass production than to verify that used one will work again.

[charliem]

Going back to the root of my original post.

SpaceX does, and I suppose all the other mayor players also do, test multiple times each of the main systems of its launchers.

For instance every engine is fired first for a short period, then longer, then integrated, and again, etc.

That level of testing, piece by piece, once and again, has to be expensive.

What would be the consequences of relaxing it a bit, in costs and reliability? Anyone with an estimation?

In the long run RLVs may look a better promise than making cheap expendables, but those are not mutually exclusive strategies (and I think, just my opinion, that full reusability is going to take more time than what some people believe).

[edkyle99]

Rather than developing a BDR, just fly Atlas 15 times per year instead of 5, year after year for decades.  The per-launch cost would drop by one-third or one-half, probably, and 98 percent of the payloads would get where they're supposed to go.
 - Ed Kyle

Careful Ed, "generalizations" have a habit of coming back on you

Increased manufacturing rates do NOT always maintain reliability rates and tripling the amount of Atlas CCBs built WILL introduce, (even encourage if you will) lower reliability overall.

Russia/USSR's R-7 reliability actually increased when its launch rate grew.  Reliability was best during the 1980s when R-7 flew nearly 56 times per year.  The same is true of the retired Atlas Centaur, which became more reliable during the 1990s when it flew more frequently than it ever had before.

 - Ed Kyle

[edkyle99]

Planes are about as expensive as rockets.

But you don't throw them away after a single use.

Because they don't reenter the atmosphere at Mach 23 during each flight.

 - Ed Kyle

[93143]

That's the point.  You don't throw them away after each use.

You have no proof for that, it's just your personal assumption. Do you have data?

Of course.  You should know this too.  Aircraft are reused multiple times.

QED.

Read what I type, not what you think I mean.

...

The reason aircraft are cheaper to use than rockets is that you don't have to build them new each time.  This is not the same thing as saying that the reason rockets are more expensive to use than aircraft is that you do have to build them new each time.  I didn't say that.

[Proponent]

"Minimum cost design", if you are talking about the classic "Big Dumb Booster" idea, has never been employed.  There are several reasons.  One reason is because the payloads cost more than the rocket - sometimes multiple times more than the rocket.  The Dumb rocket might be able to tolerate an above-average failure rate, but the payloads cannot.  Even if the payloads are propellant tankers, they still have great value in the context of a complex, costly mission buildup sequence.

To reiterate what others have said above BDR and MCD aren't the same.  Minimum-cost design's originator, Arthur Schnitt, did not suggest trading reliability for cost.  His point was rather that minimizing the cost of an expendable launch vehicle is not the same as minimizing its mass.  Hence, particularly for lower stages, he suggested the use of larger margins and heavier materials to minimize cost without affecting reliability.

EDIT:  "CDR" -> "BDR"

[savuporo]

"Minimum cost design", if you are talking about the classic "Big Dumb Booster" idea, has never been employed.

I'm not talking about BDR. Big, by its very definition can never be minimum cost, because of the associated infrastructure, and inherently lower flight rate for the same fixed size of the payload market.

Perhaps a better candidate for MCD rocket design would be a simple, low performance, small booster, that can still make orbit, not necessarily dumb though ( not dumb in the sense of integrating a ton of electronics and instrumentation sensors that have actually very little materials cost, so you can get good feedback loop about failure modes )

And to your second point, yes current payloads are very expensive comparatively, but this entire thread is based on the premise of emerging market of propellant tankers, or other bulk payloads.

[pippin]

The reason aircraft are cheaper to use than rockets is that you don't have to build them new each time.  This is not the same thing as saying that the reason rockets are more expensive to use than aircraft is that you do have to build them new each time.  I didn't say that.

OK, but what's the point then, if you do _not_ want to imply rockets should be reused, too?

[wolfpack]

So far, re-usability did not help getting costs down and again - rocket makers are not dumb.

I think we need to define re-useability. I agree completely that just because something is re-used does not in any way shape or form imply that it costs less. Shuttle was a perfect example. SRB's dropped in the ocean, had to be retrieved, disassembled, shipped to Utah, reloaded, reassembled, etc. The orbiter itself required that the engines be removed and reinstalled, new tires installed, often times TPS replaced among many other things. Yes it was mostly re-used. But it certainly cost a ton of money!

Compare that to SpaceX's *plans* (yes, I said plans) to flyback at least a first stage booster. I think that *could* reduce costs. No ocean recovery, no elaborate TPS. If they can simplify it down to basically flushing out the plumbing and reloading the propellants (heck, throw in a wash-n-wax too) then I think it will be cheaper. Time will tell.

[pippin]

Well, I didn't mean to imply it's impossible to bring down cost through re-use, I just believe it's quite some way left until somebody gets there.

But your example is a good one. Let's look at what that means, essentially what they have to do for the Grashopper:

You need:
- additional structure and fuel to sustain re-entry (even for the first stage, currently they are breaking up) and to RTLS
- You probably DO need some TPS
- You'll have much,much stricter range requirements when flying back the empty stage which can add significantly to cost and availability.
- You'll probably want to still disassemble the engines to re-certify them, after that you probably want to test-fire them again. I don't believe that margins in the current design are big enough that you can assume to be able to re-use them without further checks. If you have more operational experience with the engines _this_might be a good point where you may be able to relax requirements for a tanker. If you don't max out payload and you have a decent level of engine-out capability you might be able to live with losing an engine each flight on average or something like that if the payload is cheap enough.

[93143]

The reason aircraft are cheaper to use than rockets is that you don't have to build them new each time.  This is not the same thing as saying that the reason rockets are more expensive to use than aircraft is that you do have to build them new each time.  I didn't say that.

OK, but what's the point then, if you do _not_ want to imply rockets should be reused, too?

The point is that since airplanes are as expensive as they are despite mass production, mass production of rockets is not necessarily going to help a lot.

Now, it is reasonable to point out that rockets are less complex than airplanes.  But the manufacturing costs are still significant even at very high flight rates; assuming an 85% learning curve, you'd need to build several thousand rockets, maybe a couple tens of thousands, to reduce manufacturing cost to 10% of the cost of a one-off.  And an Atlas V is not a one-off; it's been launched 28 times according to Wikipedia, meaning that reducing its manufacturing cost to 10% of its present value would involve building about half a million rockets.

Best case is that the whole incremental cost of launching a rocket is manufacturing costs, which can then be moderately reduced - remember, rockets are already mass-produced, just not at a particularly high rate; they aren't custom-built prototypes.  If a large part of the incremental cost is due to other factors, even that moderate improvement is diminished.

Obviously reuse isn't the whole story; look at Shuttle.  But I do happen to think that reusability is going to be part of any truly cheap launch system.  Personally I'm a fan of Skylon, which is being designed for low operational overhead, low maintenance requirements and fast turnaround, as well as airplane-like failure characteristics (lose an engine and you have to abort, but "abort" means turn around and land, not explode).

You'll probably want to still disassemble the engines to re-certify them, after that you probably want to test-fire them again.

Eugh, no.  If I'm not mistaken, the SSME Block III (well along but never deployed; probably the starting point for RS-25E) was supposed to be robust enough and well enough instrumented that you could just leave it in the orbiter for about ten flights (and yes, it would have been cheaper to make than the Block II).  If SpaceX can't even do that, I'll be rather disappointed.

[jongoff]

That's certainly true for precious cargo, like aerospace hardware or humans. But for bulk materials it's not inconceivable that mass produced, unreliable and expendable launchers would turn out to be cheaper. Given a market for selling propellant in orbit the market would discover what the most economical approach was.

Why plan to build "unreliable" launchers?  I'm not sure how making a launch vehicle less reliable would save money.  I'm not even sure how to save money by making a launch vehicle less reliable! 

I'm with you Ed.  I used to be in the low-cost expendable camp (having done my undergrad studies in manufacturing engineering), but I'm now firmly in the high-flight-rate reusable camp when it comes to getting costs down.  When you have a market like bulk cargo and propellants, I can't think of a better possible starter market for RLVs.  High divisible cargoes, no mission-specific engineering, no payload insurance needed, payload integration becomes very repetitive, launch licensing becomes a lot easier, the ability to easily get up into the 50ish flights per year needed to get prices down... 

I could very well be wrong--so I'm quite open to seeing how the market goes once cargo/propellant needs like that get better established, but my intuition tells me that propellants and bulk cargoes will be delivered by reusable vehicles, not by "unreliable" mass-produced expendables.

~Jon

[mmeijeri]

I used to be in the low-cost expendable camp (having done my undergrad studies in manufacturing engineering), but I'm now firmly in the high-flight-rate reusable camp when it comes to getting costs down.

So am I, at least in the long run, but Ed asked for an explanation how sacrificing reliability could potentially buy you reduced prices and then went on to ignore the explanation.

  When you have a market like bulk cargo and propellants, I can't think of a better possible starter market for RLVs.  High divisible cargoes, no mission-specific engineering, no payload insurance needed, payload integration becomes very repetitive, launch licensing becomes a lot easier, the ability to easily get up into the 50ish flights per year needed to get prices down... 

That argument actually goes the other way, it shows how bulk cargo would be ideal for RLVs, not how RLVs would be ideal for bulk cargo. After all bulk cargo makes for ideal payloads for mass-produced expendables or HLVs too. It's no coincidence that SDLV proponents want an exploration program. They too know that propellant is the only affordable payload they could ever hope to have.

[mmeijeri]

Because they don't reenter the atmosphere at Mach 23 during each flight.

Of course not, but it does explain the difference in economics.

[baldusi]

I could very well be wrong--so I'm quite open to seeing how the market goes once cargo/propellant needs like that get better established, but my intuition tells me that propellants and bulk cargoes will be delivered by reusable vehicles, not by "unreliable" mass-produced expendables.

The fact is that if you want an RLV not only will your fmr be bad, but you can only go to LEO. Ideally, low LEO. Thus, any reusable infrastructure would need a heavy use of tugs and depots. Orbital mechanics are easy for GSO and EML1/2. May be for any deep space. But LEO/MEO/SSO and such, get killed because nor only for the plane change, but for the nodal change cost. And I'm talking about the tugs and depots. The Van Allen Belt transits don't help, particularly with live cargo and SEPs.
So you sort of always will need some disposable parts in the foreseeable future. But as I stated before, you should worry about how to lower the cost of missions rather than launches. Think about avionics, propulsion modules, power distribution, integration, environmental testing, MMC, etc. Can you lower each of those to 50% of what currently cost? To 25%? To 10%?

[mmeijeri]

But LEO/MEO/SSO and such, get killed because nor only for the plane change, but for the nodal change cost.

We don't really need RLVs for launching large payloads to any of these orbits, EELV class launchers are fine for that. We do really need RLVs for transporting people to LEO. They would be excellent for propellant and supplies too, even if the RLVs are small.

[tegla]

The fact is that if you want an RLV not only will your fmr be bad, but you can only go to LEO. Ideally, low LEO.

What's wrong with RLV doing GTO?

[mmeijeri]

What's wrong with RLV doing GTO?

It would be much harder.

[A_M_Swallow]

The fact is that if you want an RLV not only will your fmr be bad, but you can only go to LEO. Ideally, low LEO.

What's wrong with RLV doing GTO?

RLV have a small payload.  On the same LV GTO payloads are smaller than LEO payloads, so that is a double reduction in size.

[93143]

Skylon's upper stage is optionally recoverable and reusable, and capable of putting over six tonnes into GTO in reusable mode.  Fluyt is reusable and can put Skylon's full 15-tonne payload anywhere in cislunar space - but of course it isn't strictly part of the RLV; it's a chemical tug based in LEO.

[baldusi]

The fact is that if you want an RLV not only will your fmr be bad, but you can only go to LEO. Ideally, low LEO.

What's wrong with RLV doing GTO?

The delta-v for GTO is a lot more than LEO. Given the rocket equation, making an RLV to LEO is very difficult. To GTO might as well be impossible with current technology. And I mean a fully returnable and easily launched vehicle.
Any realistic RLV would take two stages to LEO. The idea of a tug and depot system, is that once you have a stage that goes from LEO to GTO/EML1/TLI/TMI, there's no point on actually returning it to the surface. Just refuel it on LEO and send it up again. So you'd have a three stages to GTO, for example, but the third stage would only to LEO-GTO-LEO, never returning. You'd have to refuel it of course.

But LEO/MEO/SSO and such, get killed because nor only for the plane change, but for the nodal change cost.

We don't really need RLVs for launching large payloads to any of these orbits, EELV class launchers are fine for that. We do really need RLVs for transporting people to LEO. They would be excellent for propellant and supplies too, even if the RLVs are small.

The whole point of the thread was if cheaper launchers can be used for "low value" cargo, like fuel/water/oxygen. From there the discussion went to many people stating that they had moved from the "dumb but cheap" to the "expensive but fully returnable", after having more experience in the industry.
I like to point out that the launch cost is (usually) about 20% of the mission cost. So to really multiply the amount of missions (to justify a RLV), you'd have to lower all the areas.
The proposal underlying to both tourism and fuel depots, is that if you can make some parts of bigger missions standardized you'd save on all the mission phases.
Let's say for example tourism. If you have a fixed set of places to visit, and you repeat the mission every time on the very studied launch opportunities, and you have developed an architecture where your crewed vehicle flies many times without having to refurbish it. In other words, if you don't have to do integration testing again, and your payload doesn't need DDE&T (humans/fuel), and your mission planning is restricted to checking the known launch conditions, then you could lower your cost of that seriously (like to 20% of current costs), if you had enough amount of missions.
I state that even if you could lower your cost to 20% of current prices, the potential market is too small to justify the necessary development and construction of such an infrastructure. And that you couldn't go much lower than that.

[mmeijeri]

I like to point out that the launch cost is (usually) about 20% of the mission cost. So to really multiply the amount of missions (to justify a RLV), you'd have to lower all the areas.

Only if you are going after traditional EELV payloads, not for people (assuming you have reusable spacecraft), and not for propellant and supplies (assuming you have tugs). I see EELV class launchers and small RLVs as highly complementary, RLVs for cost-effectiveness and EELVs for "heavy lift" (20-30mT).

I state that even if you could lower your cost to 20% of current prices, the potential market is too small to justify the necessary development and construction of such an infrastructure. And that you couldn't go much lower than that.

Are you talking about the near to medium term? Because in the long term it seems almost certain we'll have RLVs. But in any event what you are saying merely points out why we don't have RLVs, not that they are physically impossible, or economically infeasible excluding development costs, or undesirable.

[jongoff]

The fact is that if you want an RLV not only will your fmr be bad, but you can only go to LEO. Ideally, low LEO. Thus, any reusable infrastructure would need a heavy use of tugs and depots.

Yes, if you're doing small deliveries to orbit, having a destination to deliver them to is definitely a nice to have...

Orbital mechanics are easy for GSO and EML1/2. May be for any deep space. But LEO/MEO/SSO and such, get killed because nor only for the plane change, but for the nodal change cost. And I'm talking about the tugs and depots. The Van Allen Belt transits don't help, particularly with live cargo and SEPs.

I recently figured out a great way to handle deep space departures from a LEO depot that can handle just about any declination, and pays a very minimal delta-V penalty (though it potentially adds a week or two of mission flight time, and an extra set of VAB transits).  Thanks to an old MXER tether article by Kirk Sorensen of all people (ironic because Kirk hasn't seen the light yet on LEO depots...)

And unless you mean transfer tugs, the D2S work we're doing at Altius is aimed at eliminating the need for prox-ops tugs.

On the SEP side of things...I'm actually with you on being a very big anti-fan of SEPs especially for use within cislunar space.  Maybe for missions starting at EML2, but their long transit times getting out of earth's gravity well combined with their very high unit costs make me think they'll end up on the bad side of the marginal cost equation once the price of prop in LEO drops past a certain point.

~Jon

[jongoff]

The delta-v for GTO is a lot more than LEO. Given the rocket equation, making an RLV to LEO is very difficult. To GTO might as well be impossible with current technology. And I mean a fully returnable and easily launched vehicle.

Unless you refuel the RLV upper stage in LEO.  The delta-V from LEO to GTO is much less than your typical RLV sees on its leg to LEO.  And it has a heat shield that could very well serve as an aerobrake.  It's not clear if it's better to do it that way than to build a dedicated GTO transfer vehicle (expendable or reusable), but when we're talking about using RLVs to deliver propellant per orbit, it's pretty much assumed that we'd be talking about a depot-centric architecture, at which point having some of the RLVs use propellant from the depot to boost a payload from LEO to GTO (or even all the way to GEO) isn't necessarily crazy at all.

Any realistic RLV would take two stages to LEO. The idea of a tug and depot system, is that once you have a stage that goes from LEO to GTO/EML1/TLI/TMI, there's no point on actually returning it to the surface. Just refuel it on LEO and send it up again. So you'd have a three stages to GTO, for example, but the third stage would only to LEO-GTO-LEO, never returning. You'd have to refuel it of course.

That's also a perfectly legit way of doing things.  How the trades turn out in any given case is probably highly dependent on assumptions, but having an in-space only tug stage is a good idea.  Depots are really key for allowing you to reuse in-space elements, which as you've pointed out, are some of the major cost drivers in any transportation architecture.

I like to point out that the launch cost is (usually) about 20% of the mission cost. So to really multiply the amount of missions (to justify a RLV), you'd have to lower all the areas.

The thing is that many of the other cost areas (insurance, in-space hardware fabrication, etc) can be impacted by the availability of cheaper, more frequent launch, and propellant depots.  If you don't have to relaunch your mission hardware every time (just new people, propellant, and provisions), you can start cutting overall mission costs rapidly.

The proposal underlying to both tourism and fuel depots, is that if you can make some parts of bigger missions standardized you'd save on all the mission phases.
Let's say for example tourism. If you have a fixed set of places to visit, and you repeat the mission every time on the very studied launch opportunities, and you have developed an architecture where your crewed vehicle flies many times without having to refurbish it. In other words, if you don't have to do integration testing again, and your payload doesn't need DDE&T (humans/fuel), and your mission planning is restricted to checking the known launch conditions, then you could lower your cost of that seriously (like to 20% of current costs), if you had enough amount of missions.

Quite possibly even further with a reusable system.  I'd be really surprised if a fully-reusable gas-and-go style reusable couldn't get a ticket price down to $1M or less to LEO.

I state that even if you could lower your cost to 20% of current prices, the potential market is too small to justify the necessary development and construction of such an infrastructure. And that you couldn't go much lower than that.

I politely disagree.  I think that many of those other areas of cost you talk about (the other 80%) can also be driven down once you have depots and RLVs.

~Jon

[edkyle99]

Hence, particularly for lower stages, he suggested the use of larger margins and heavier materials to minimize cost without affecting reliability.

So, a rocket with a minimum cost design lower stage would look something like this?



 - Ed Kyle

[baldusi]

I like to point out that the launch cost is (usually) about 20% of the mission cost. So to really multiply the amount of missions (to justify a RLV), you'd have to lower all the areas.

Only if you are going after traditional EELV payloads, not for people (assuming you have reusable spacecraft), and not for propellant and supplies (assuming you have tugs). I see EELV class launchers and small RLVs as highly complementary, RLVs for cost-effectiveness and EELVs for "heavy lift" (20-30mT).

There's a couple of points here. I'd like to separate lots of people to a single point (say, a Med Club at EML1), from fuel. Sending people to a single place in space might get very cheap. But let's analyze the costs. I'm not that experience and there might be cheaper was of doing this.
But as long as you launch rockets, you have to contend with range limitations. I.e. you have to send a small army of boats and crafts to make sure there's nobody in your flight path. You have to use and pay for the telemetry/radar stations/satellites. You have to make constant analysis of trajectories and possible collisions avoidance. You have to check the weather conditions (weather balloons, etc.). All this means lots of money. It's very little when launches are in the hundreds of dollars. But if you want to go towards single digit millions, all this starts to be a significant percentage of costs.
Then you'd have that mythical place in space. You'd need an MCC for that. And constant resupplies. The cost of a passenger to a station is not the crew transfer. Is that, plus the consumables, plus the spare parts, plus the ground controllers, plus the communication costs, etc. So even if sending a single person would cost 1M, it would cost significantly more per person.
But then there's the issue of fuel. Fuel has to be on an useful place. If not, you'd have to move your depot. Since even nodal point change is pretty expensive in delta-v terms, you'd have to launch fuel to move depot, move the depot, second launch to actually fill the depot for the mission, and then the third launch to actually launch the mission. So now you need three launches for one mission. Remember, all the stuff I named before. Those controllers and orbital engineers are not cheap. Nor the range services.
I'm not saying it's not possible to do it. I'm saying that you'd need to have the actual launch costs on the single digits percent of current costs. And that's incredible difficult to achieve. Even a Falcon 9 fuel is about 3% of the total launch cost. So lowering to less than 6% (very few industries have bigger fuel costs than that) of current costs seems plain impossible with current rocket technology.
Then there's a different issue that I would like to touch. Actually it's a sort of contradiction. On the one hand, once of the drivers of launch market is not USD/kg only. I'm sure a 1000tn to GTO launcher would be very cheap on that account. But who will be able to afford such a ticket? On the other hand, if you could launch 1kg for 5.000USD, you could do a lot of very interesting things. But because that is a small ticket. So the market should also be analyzed from the single ticket perspective.
But then there's the other issue of economies of scale above mentioned. I'm sure it's a lot simpler to achieve a low USD/kg for a "big" graft, than a "small" one. So I see that the only way to get low per passenger cost, will be by carrying a lot of people per flight. Ditto for the fuel. So I see the RLV actually being very big.
Do you see the dichotomy? The big market is small total amount of money, and the economies go to big amount of payload in single launch. In that sense I see the nanoracks to ISS as pure genius. But that's part of the problem I see in developing this market.

[charliem]

Economies of scale are a possible way to cut prices down but not the only ones.

Comparisons can help. I propose building and operating big crude oil tanker ships.

It is not uncommon that cargo value surpasses the cost of the ship. The number built every year is small so economies of scale are not possible, and the demand for their services is quite inelastic.

Even so their cost per tonne have been constantly decreasing for decades (partly because they have become bigger, but not only for that, also inside the same tonnage category).

Maybe we could learn one thing or two from shipyards and shipowners.

Listing all the things that have to be payed for (to take something to orbit) gives info about why that's so expensive now, but offers no clue about how hard (or easy) is going to be to cheapen it.

[baldusi]

Economies of scale are a possible way to cut prices down but not the only ones.

Comparisons can help. I propose building and operating big crude oil tanker ships.

It is not uncommon that cargo value surpasses the cost of the ship. The number built every year is small so economies of scale are not possible, and the demand for their services is quite inelastic.

Even so their cost per tonne have been constantly decreasing for decades (partly because they have become bigger, but not only for that, also inside the same tonnage category).

Maybe we could learn one thing or two from shipyards and shipowners.

Listing all the things that have to be payed for (to take something to orbit) gives info about why that's so expensive now, but offers no clue about how hard (or easy) is going to be to cheapen it.

Please stop using the oil market as an example. The amount of oil transported is huge. What you consider "few" tankers is actually a huge number. Since shipyards are sized for building one or even less tankers per year. And the tankers have operation lives of more than 20 years. Thus, cheap financing would lower the cost of transport (through it's effect on both amortization and financial burden).
What most people here seems to be failing to grasp, is that RLV/cheap rockets aren't only possible, but highly studied, and we have current examples. Take the Shuttle, or even the Delta IV. At 24 launches/year both LV would have been very cheap. The fact is that there's not enough payloads to reach those rates. Let me strengthen this point:
The LV cost problem is lack of payload quantity elasticity to price
If you want cheap LV you've gotta have orders of magnitude more payloads. As it's now, you could slash by half the cost of LV, and yet you wouldn't have many more payloads. What's worse, most of national defense markets in the world are much more politics sensitive than price sensitive. Russian National payloads will fly on Russian rockets, same for China and the US and, to an extent, India. The European seem to use a mix of Ariane 5 and Soyuz. But since they will have everything on Kourou, it's almost the same situation.
So even if you could launch at 20% of current costs, you'd only get into to "commercial" market. Which is very price inelastic (even though it's very price sensitive). Price sensitive means that a LV operator has to compete every single launch and very small percentages of discount can win or lose a launch contract. Price inelasticity means that even if the whole launches industry made huge reductions in price, there would be very little extra payloads.
So, my conclusion is, don't work on making LV cheaper, work on making payloads cheaper. Even current LV can have huge cost reductions from more payloads.

[charliem]

Please stop using the oil market as an example. The amount of oil transported is huge.

And why should I do that? That's a difference alright, but I see more similarities, and if similarities outnumber differences I don't see why not comparing.

And I think there's a much more relevant difference than the size of the cargo, that all those sea ships are reusable tens or even hundreds of times.

About similarities I see:

1) Quite few oil tankers are built every year. According to the CIA World Factbook the number of them in service (10.000 long tons and above) is around 4,000. If we accept 25 years as their mean life that implies that some 160 are made every year. The number of LV is in the range of dozens. Not that far.

2) For the biggest tankers the value of the cargo for one trip is higher than the cost of the hardware plus the cost of operation also for one trip. Not dissimilar than a launcher.

3) The cost per unit of big tankers is in the same range than LV, from tens to hundreds of millions.

4) The market for oil transport by sea is inelastic. No decrease in its price is going to make the world consumption increase significantly. About LV we don't know for sure.

5) Insurance amount to a significant part of the costs in both cases.

Take the Shuttle, or even the Delta IV. At 24 launches/year both LV would have been very cheap. ...
The LV cost problem is lack of payload quantity elasticity to price

Well, I'm not so sure. I remember reading that the big computer companies of the 50's said the whole world market was no bigger than a few tens in the foreseeable future. Then in the 60's repeated it, just giving the figure another zero, and even during the 70's, when PCs have already appeared some still affirmed that the thing would not sell more than a few thousands.

You can imagine that if todays computers were as expensive as those from the 50's they could have very well been right.

We can't see the future, and THAT is a well established fact.

As it's now, you could slash by half the cost of LV, and yet you wouldn't have many more payloads.

Well, at least this is something we are going to verify soon enough. SpaceX has more than slash it that half (Atlas V 401, 9.8 mt to LEO for $130-150 M, Falcon 9 block 2, 10.4 mt to LEO for $50-60 M). We'll see if they make the global launch market bigger or not.

So even if you could launch at 20% of current costs, you'd only get into to "commercial" market. Which is very price inelastic (even though it's very price sensitive). ...
So, my conclusion is, don't work on making LV cheaper, work on making payloads cheaper. Even current LV can have huge cost reductions from more payloads.

Well, in my opinion current LV can have their cost reduced from more payloads, but "huge" reductions? I'm not so sure. More than just the frequency of flights have to change to see costs cut by ten or more.

And that's exactly were big oil tankers come into play, they have been able to reduce their prices almost continuously for the last 40 years even having to deal with an inelastic market (this one for sure).

[Xplor]

At the start of the international "commercial" launch era in the 1990's the price of launch dropped by a factor of 2.  The dot com boom promised a huge jump in payloads, not because of the reduced launch price but driven by the internet market demand.  Reality showed that the market was basically inelastic, no growth.  All that happened was launch companies around the world loosing a lot of money.

[oldAtlas_Eguy]

At the start of the international "commercial" launch era in the 1990's the price of launch dropped by a factor of 2.  The dot com boom promised a huge jump in payloads, not because of the reduced launch price but driven by the internet market demand.  Reality showed that the market was basically inelastic, no growth.  All that happened was launch companies around the world loosing a lot of money.

The Internet demand did show up but 20 years later. The big comm birds currently going up are related to internet demand. The NEXT Iridium constellation will have a much improved data capability. But alas what is happening is that the traditional comm birds are just being swapped for more powerful data birds, there isn’t a significant count increase just a operational mode change.

[pippin]

I don't think "big" comm birds right now can be seriously used for internet. GEO sats have way too much latency to be useful for that, for internet you need LEO or cable.
Latency these days is more of an issue than bandwidth.

[oldAtlas_Eguy]

I don't think "big" comm birds right now can be seriously used for internet. GEO sats have way too much latency to be useful for that, for internet you need LEO or cable.
Latency these days is more of an issue than bandwidth.

The IP (Internet Protocol) can handle latency better than other forms of communications since there is no actual time specification for how long a packet is to take point to point. There is only a timeout which is purely based on the local software which is usually on the order of 60s to 3min.

[oldAtlas_Eguy]

Sorry for the off topic. Back to topic.

I was curious about the sensitivity of per flight cost of RLV and ELV to observed reliability (not design) to see if there were possible local minimums that showed that a general level of reliability would produce better costs than a lower one or higher one.

Results:
For an RLV there indeed is a minimum (for the successful flight costs: a failure must be charged to the other successful flights increasing their costs) and in my cost model it occurred around a 92% observed reliability. The reason for this is that the vehicle designed for use 10 times was averaging only 6 uses because of a failure cutting the vehicle life short. Lower reliability such as 80% made it nearly an ELV.

For an ELV there is also a minimum (for the successful flight costs: a failure must be charged to the other successful flights increasing their costs) occurring at 50% observed reliability.

Using the same relationship between reliability and original hardware cost and operation costs the resulting best RLV cost per successful flight and best ELV successful flight is nearly the same, in my model $26M RLV and $21M ELV which is loosely based on FH costs. The only significant item here is that the ELV not being designed for return would deliver nearly twice the payload to orbit than the RLV:  ~$1,000/kg for RLV to LEO and ~$500/kg for ELV. A very high reuse RLV that has a high reliability might be able to compete with the ELV price, I will see what happens when the model uses higher design reuse numbers stay tuned. There is also the fact that schedules would be easier to keep with the higher reliability RLV vehicle than the very low reliability ELV. The last item due to the payload capacityies and the total number of flights to succesfully deliver a set amount of prop the flight rate for the higher reliable RLV and the low reliable ELV would be the same, you need 2 ELV for each 1 RLV flight to succesfully deliver prop.

[pippin]

IP can handle the latency, but it makes the whole communication look laggy and some application layer stuff, e.g. games, will not work at all.
TCP, to begin with, doesn't really like it, too.

It doesn't help if the protocol supports it well if it isn't suited for the application. I have used a high-latency network in the early days of 3G and I can assure you it doesn't make for a good user experience so it' something you can only sell in places where you don't have any alternatives for internet access.

But OK, 'nuff OT....

[Xplor]

I was curious about the sensitivity of per flight cost of RLV and ELV to observed reliability (not design) to see if there were possible local minimums that showed that a general level of reliability would produce better costs than a lower one or higher one.

Very interesting topic.  Are you aware of any operational data shows the payload cost vs. reliability?  It seems like there are so few vehicles and so many differences that it would be very difficult to decipher a trend.

[baldusi]

I will only state that you are discussing a supply solution to what's fundamentally a demand problem. For a fuel tanker there must be a fuel depot necessity. And willingness to pay the cost of transport. There's nothing of that. The comm market is very small. Even Iridium NEXT will need no more than eight flights. How many LEO constellation are really needed? Four? With an average life of ten years that would mean 3.2 launches/year. Now what else do you have?

I was curious about the sensitivity of per flight cost of RLV and ELV to observed reliability (not design) to see if there were possible local minimums that showed that a general level of reliability would produce better costs than a lower one or higher one.

I would love to see your model. But have you taken in consideration the cost of the payload?

[savuporo]

I will only state that you are discussing a supply solution to what's fundamentally a demand problem.

Hear hear.

Or, to put it more accurately, the world launch market is so far up the left hand peak of the price / demand curve, that no valleys are seen.

[baldusi]

I will only state that you are discussing a supply solution to what's fundamentally a demand problem.

Hear hear.

Or, to put it more accurately, the world launch market is so far up the left hand peak of the price / demand curve, that no valleys are seen.

One of the ways to find out if it's a problem of demand or supply, is to assume one is infinity quantity at zero (for supply)/infinity(for demand) price. So let's make the mental exercise of assuming free launches.
For any of current satellite systems, the cost of a satellite is so high that it wouldn't make more than a 30% price difference.
Why, because you have to use space rated elements, because everything has to be meticulously integrated and tested. Because every design has to be validated. And because you can't really have much commonality. I mean, a GSO sat can be very standardized. But even for SSO or Polar orbital satellites you have lots of different requirements.
But even if you could, and you assumed free launches and free satellites, you'd still rather have a couple of huge comm sat than thousands of small size. Because operations cost is almost lineal to the amount of sats that you put up.
And even if you had that for free, you have 720 orbital slots. If the satellites have a half life of 15 years, that would be 48 launches per year. Now a days you have around 20 or so. And that's not accounting that satellites might extend their lives to 20 years. But putting everything for free you'd still just double the number of launches.
There's only so much observation sats, and ditto for LEO constellations. If you make your numbers and everything save operation was free, you'd double, may be triple the amount of launches. And you're not considering the fact that every wannabe power likes to have their own launch vehicle and satellites.
What I'm trying to say here, is that you can't grow very much the LV market with current payloads (i.e. comm sats/earth observation sats). You've gotta create a whole new category of market. A need. A tanker is a solution, is an expansion of the supply. It doesn't creates demand.
Now, tell me that you have a business idea as ridiculous as making a golf course on the moon and charging 100M of affiliation fee, plus 100M for a two week stay, and the cheapest way is to do it with tankers, then that's getting close to a solution.
Build huge ships and make a "cruise" on a free lunar return trajectory? That's another idea. But whatever you propose has to make the need for extra launches. Current needs are less than current supply.
And let me state very clearly that the only reason that NASA and DoD are paying more each year has to be with their restriction to use US LV. Let them use Russian, European, Japanese, Indian or even Chinese launches, and your launch costs would be much lower.

[savuporo]

...What I'm trying to say here, is that you can't grow very much the LV market with current payloads (i.e. comm sats/earth observation sats). You've gotta create a whole new category of market. A need. A tanker is a solution, is an expansion of the supply. It doesn't creates demand.
Now, tell me that you have a business idea as ridiculous as making a golf course on the moon and charging 100M of affiliation fee, plus 100M for a two week stay, and the cheapest way is to do it with tankers, then that's getting close to a solution...

Very much right. There is an angle here though : current payload builders are NOT thinking in terms of cheap bulk payloads at all, just because such launchers do not exist. Hence, nobody comes up with these required ridiculous-but-may-actually-work business plans that would utilize such launchers.

Say that one would run numbers on a theorethical orbital 3D printing/manufacturing facility that requires tons and tons of bulk supplies of metal and plastic powders for the printers and SLS sintering machines, water and other bulk supplies. And it would actually have customers.
Right now, the business plan would have to include the design, development, tooling, manufacturing setup of the theoretical bulk launcher.
Its two leaps of faith in one business plan, that will never get funded by angels, VCs or anyone really.

The only remote possibility is that someone funds the launcher side with a "build it and they will come" mentality, and starts flying dummy or almost worthless payloads on it. And then has years of funding to keep it ticking like that without any real customers, allowing business plans to come forward.

[savuporo]

To put it very clearly, there is no current supply OR demand for bulk, maybe unreliable materials launches, including propellant.

The are no such launchers, and no applications demanding such launchers.

Orbital RLVs are better off in that regard : they always have humans as payloads as the market to rely on. That demand and market undoubtedly does exist, and business plans hedge on estimated the size and price elasticity curves of that market.

For "bulk" or "tanker" launches, both sides do not exist. Very hard to break that without either public funding on one side, or really really massive business plan trying to break both sides at once.

[baldusi]

That was a bit what I was trying to make. Exploration is not a viable market now a day (unless the 10B+ billionaires of the world suddenly decide to spend money on it for the sake of it). Communication and Earth Observation are probably at 25% of their maximum even if launches and satellites were free. And in any case we are are seeing the market moving towards fewer and more capable birds rather than smaller and cheaper. And many of the increases can't be launched by the same vehicle given national interests.
So if you want cheap LV you have to find or invent an economically viable necessity. Try tourism, energy, manufacturing or whatever you can think of. Just remember, a 40' container cost 2.5USD/kg to move across the globe. So don't even start to talk about mining other objects unless you find a source of monopoles or a clump of antimatter. Anything else is too expensive. And don't do the circular fallacy of saying that you make fuel/food on the Moon or Asteroids for exploration, since the exploration itself isn't economically viable. And if you are thinking about space tourism, let me remind you that if a ticket was 100k/passenger, and SpaceX was transporting 5000 passengers per year (ten times the total passengers ever), they would still have less revenue than four CRS flights.
I would love there to be a market. But I think even something as sophisticated as crystals for semiconductors can be done more cheaply on the Earth. I would love to be able to pay just 100k for a Zond like flight to the Moon. But there just isn't a market for that yet.

[oldAtlas_Eguy]

There are cheaper US LV's but they are not certified to carry NASA and DOD payloads yet. That's the rub for entry LV's, getting certified in order to get government payloads.

BTW COTS being a contract for succesful delivery of, relative to launch costs, low cost supplies is structured such that attempts are not paid for just success. No certification neccesary for the launch of one of a kind costly payloads, since the supplies are neither one of a kind or costly.

[oldAtlas_Eguy]

The first results I reported were on a log/log relationship between reliability and manufacturing/launch processing & ops.

I checked to see what effect the basic relationship with reliability has with the conclusions:

For RLV

Case 1: log/log – this model has a minimum per successful flight cost in the low 90% observed reliability.

Case 2: linear/log – this model has a minimum per successful flight cost in the mid 90% observed reliability close to 95% and probably will be below 95% for most specific situations.

Case 3: log/linear – this model has a minimum per successful flight cost in the mid 90% observed reliability close to 95% and probably will be below 95% for most specific situations. Although this looks to be the same as case 2 this model produces a minimum at reliability consistently higher than case 2.

Case 4: linear/linear – this model does not have a local minimum. It shows that for an RLV the highest obtainable reliability will be the lowest cost, which sort of goes against first impressions.

The RLV cost model definition:

Manufacturing cost:
=((1-.95)/(1-Reliability))*$95M – logarithmic relationship;
=($95M/.95)*Reliability – Linear relationship
[Note: both models are pined at 95% observed reliability to a cost of $95M. Observed Reliability is the number of successful flights to the total number of flights, not the design reliability.]

Launch Processing & Ops cost:
=((1-.95)/(1-Reliability))*$20M – logarithmic relationship;
=($20M/.95)*Reliability – Linear relationship
[Note: both models are pined at 95% observed reliability to a cost of $20M or ~20% of the total launch costs at the 95% case which the model is pinned to. Observed Reliability is the number of successful flights to the total number of flights, not the design reliability.]

Average number of successful flights per vehicle:
[Design life]*Reliabilty^[Design Life]
[Note [Design life] in the model is set at 10. Also if you have a better more accurate mathematical model of this it would be appreciated.]

Additional loss of use of vehicle due to early loss prior to design life retirement:
=(1-Reliability)*(SUM[x from 1 to [Design life] ]([ Launch Processing & Ops cost]+[Manufacturing cost]*([Design life] – x)/[Design life])/[Average number of successful flights per vehicle]
[Note: For a service that only gets paid when the payload is delivered (the pure commercial model) in this case prop at the depot, the additional costs of loss must be added to the cost of the successful flights.]

Total cost per successful flight:
=([Manufacturing cost]/[Design life])+[Launch Processing & Ops cost]+[Additional loss of use of vehicle due to early loss prior to design life retirement]


For ELV:

Case 1: log/log – this model has a minimum per successful flight cost at 50% observed reliability.

Case 2: linear/log – this model has a minimum per successful flight cost at 50% observed reliability.

Case 3: log/linear – this model has a minimum per successful flight cost at 50% observed reliability.

Case 4: linear/linear – this model does not have a local minimum. It shows that for an ELV the no matter the reliability the costs are the same. This is an improbability and shows that the linear/linear model does not reflect reality invalidating this case for both the ELV and RLV scenarios.

The ELV cost model definition:

Manufacturing cost:
=((1-.95)/(1-Reliability))*$95M – logarithmic relationship;
=($95M/.95)*Reliability – Linear relationship
[Note: both models are pined at 95% observed reliability to a cost of $95M. Observed Reliability is the number of successful flights to the total number of flights, not the design reliability.]

Launch Processing & Ops cost:
=((1-.95)/(1-Reliability))*$20M – logarithmic relationship;
=($20M/.95)*Reliability – Linear relationship
[Note: both models are pined at 95% observed reliability to a cost of $20M or ~20% of the total launch costs at the 95% case which the model is pinned to. Observed Reliability is the number of successful flights to the total number of flights, not the design reliability.]

Additional loss requiring replacement flight:
=(1-Reliability)*([Launch Processing & Ops cost]+[Manufacturing cost])
[Note: For a service that only gets paid when the payload is delivered (the pure commercial model) in this case prop at the depot, the additional costs of loss must be added to the cost of the successful flights.]

Total cost per successful flight:
=[Manufacturing cost]+[Launch Processing & Ops cost]+[Additional loss requiring replacement flight]

[baldusi]

Just to start, when you want to know how many launches you can expect form a launcher given:

p: Success Probability
Dl: Design Life

Then it is
Expected Life = Dl x p ^ Dl + [(1-p) x SUM (n=0 to Dl-1){n x p ^ n}]

Here is where I would ask you to start a new thread on Policy or somewhere like that, starting with your previous post. Because if we are going to develop an economic model, it will get long.

First thing to define here is if you are going to do an integrated analysis, where you make both payloads and launcher (i.e. govt style) or are you trying to fit a launcher in the market.
In the first case, you'd want to minimize the total present value cost, but that means adding the average cost of the payloads to each failure.
In the second case, you'd need a demand curve that's dependent on the reliability and service price, but then again, you'd have to derive a demand curve that includes payload cost, operation, insurance and lost revenue.
Generally when you start an economic analysis you try to make a very simple model, and then start adding things. Yours is a good point to start a discussion.
One of the things that I would think on first approach, is that you have to take into account the development cost, as a function of the desired reliability, expected launch rate, design life and desired launch cost, at the very least.
The difficulty is in defining the model. Then finding the optimum is basic calculus (basic if you are used to bordered hessian and dynamic problems, that's it). How would you like to go forward?

[oldAtlas_Eguy]

p: Success Probability
Dl: Design Life

Then it is
Expected Life = Dl x p ^ Dl + [(1-p) x SUM (n=0 to Dl-1){n x p ^ n}]

Thanks for the equation correction the RLV cases only showed movement to lower reliability values for the local minimum cost in case 1,2,&3 (81%,89%,89%) but no basic differences for the conclusion that for RLV’s designing with good reliability is best in the long run economically.

My goal for the model was to see if the basic premise of lower reliability is better from a cost per successful flight is correct or not. For RLV not really, for ELV probably yes but it will probably still be more expensive than a cost efficient RLV or end up breaking even on a $/kg to LEO.

[baldusi]

My point was that you have to add the payload cost. This is not only the hardware, but the whole operation and lost profit. Which again will run the operations towards high reliability.
Now, this doesn't means that having a fault tolerant architecture where the individual parts are less reliable but the overall mission is highly reliable might not be a possible solution.

[oldAtlas_Eguy]

My point was that you have to add the payload cost. This is not only the hardware, but the whole operation and lost profit. Which again will run the operations towards high reliability.
Now, this doesn't means that having a fault tolerant architecture where the individual parts are less reliable but the overall mission is highly reliable might not be a possible solution.

For the cost model the payload was propelant. A low cost item that would be contained probably in a stretcehed US to eliminate the need for a seperate container and set of systems. So there is no cost of payload per say just the booster. Unfortunately this would also be a single use LV, something that at this time is definitly not an economic possibility.

Yes in the end I believe higher reliability will in general be better economically especially for RLV's.

I think SpaceX has persued the redundancy method both electronic and engines as about as far as the current tech alows while still keeping costs low. Although there may still be more that could be done.