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Dear rocket co, what is your opinion of the low cost Russian or Ukranian boosters?
Can SeaLaunch sustain current Zenit pricing? If demand grew significantly, could Zenit be mass produced with costs falling below current rates?
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My reply to author’s reply_
Firstly may I say thank you for replying to my questions. However as you will see below, I still do not agree with much of the plan.
Author’s reply;
(1) 'Build it and they (customers) will come' has already been tried. It's called 'Shuttle'. They did not come.
1. The Shuttle was a government program and was never aimed at making money.
(1 again) … and despite that, they STILL did not come. No, your business plan would not work; there just is not the traffic. What’s needed is cheap access to LEO that also offers something else not available today, like true heavy lift. Then you could do useful things like hoisting the ISS in a couple of lifts, or a manned expedition to Mars in the same. Yes you could do this with DH-1, but it delivers to orbit penny-piece loads that would make shuttle look like a heavy lifter, which means an AWFUL lot of assembly space walks in LEO— which is asking for disaster, quite apart from anything else. If you doubt this, look at the state of Shuttle today.
(2) Don't forget NASA promised Shuttle would deliver payload to LEO for $60/lb. The actual true cost is a closely guarded NASA secret, but it's certainly well over $10,000/lb and may be as much as $20,000/lb. (That's why it's a secret.)
2. In the book the Company sells launch vehicles at $250,000,000 a pop. As will be discussed in the epilog it takes ten years of operating the vehicles at a loss to get to low cost transportation.
(2 again) Sorry, I don’t believe your quarter billon dollar unit cost. I think you grossly underestimate development costs for one thing, and then the size of the potential buyer’s market for DH-1. If you picked up (directly or by vehicles sold to others) the entire market for payloads of the mass you promise, you would still only need maybe two or three for the whole world. On that basis your breakeven selling price is probably more like 2.5 billion dollars each*, say, which puts the probable cost/lb to LEO at $2,000 or so. Maybe more, unlikely to be less. Remember that fundamentally, cost/lb to LEO is the only thing that matters. Expendables would be a lot cheaper, but see below on that.
* You ignore the effect of amortization and interest (what you might call the financing cost) on costs, as I have above also. Real world, you (and I) could not do that, and over say ten years these might come close to doubling actual real folding money required. That might push cost/lb to LEO up to something more like $3,500, real world.
(3) In that light, TRC's promise of $200/lb to orbit (which, allowing for inflation, is just about the same as NASA’s famous $60/lb promise) must be taken with a gigantic pinch of salt. In the first place, it represents a price reduction from the real-life Shuttle cost of between 50 and 100-fold. The very best achieved today, by the Russians and ESA, is around $4,000 to $5,000, and these are not manned vehicles. But TRC promises a manned vehicle that's 20 to 25 times cheaper. Yeh, right. If I were you, I'd not be holding my breath.
3. We know that cost of many products has fallen dramatically over time if there is no fundamental reason why they can’t. The Saturn V used 22 lb of propellent per pound to orbit. Or about $5 a pound. That said no one knows how the possibility of low cost space transportation, will be achieved. The point of the book is to say; sell the vehicle not the services and used no new exotic technology in the vehicle.
(3 again) The cost of propellant/lb to LEO always has been an almost insignificant fraction of the total cost/lb. So? As for selling the vehicle … well, I’ve already stated that I don’t believe the market exists.
(4) What's more, the additional cost of man-rating a vehicle has been disregarded in all this, but you can generally assume it will increase design and build cost by at least 100%.
4. For a reusable it does not cost more because the reliability is need anyway.
(5) What's yet more is the additional cost of design and build to make a vehicle re-usable rather than expendable is also ignored. Another 100% on top again, please.
5. The development cost is set at $3-7,000,000,000 about that of a new jet transport. The technology proposed is less complex than a jet airliner and the vehicle is a lot smaller. The Falcon V under development by Space-X has twice the payload at a cost of $12,000,000 vs $250 million for the DH-1.
(4 & 5 again) Designing and building for man-rating and for reusability are not the same thing.
(5 again) If we take the median development cost, $5 billion, add on say $4 billion financing costs, we have spent $9 billion before we build a single production line vehicle.
Let’s say, in line with your belief, oh… 100 are ordered in the first decade and you want to break even by the end of that period. That means development and financing have to be able to write off some $90 million against every sale, which means you have a budget of $160 million for everything else in order to sell at $250 million/unit without loss— or profit either. Can you do that? On the other hand, suppose just 10 are ordered in that decade. In that case development and financing have to be able to write off some $900 million against every sale before you even start building the first “for sale” unit. And if my guesstimate of, say, 3 units turns out to be right, development and financing have to be able to write off some $2.7 billion against every sale before you even start building that first “for sale” unit. And of course, the fewer units sold, the more each unit will cost to make anyway as it becomes less and less practical to use production-line techniques; they’ll effectively be hand built, which is not cheap.
If you think you can make this thing profitable you're a braver man than I am, Gunga Din.
(6) What on earth is the point of a pilot in Stage One? I thought elevator operators had died out as a breed some time back. With its straight up, straight down flight path, I doubt it would take even a particularly expensive computer to do the job— say one of today’s laptops?
6. A pilot will make the stage more reliable and in the long run a piloted stage is going to be easier to license for launch near population centers.
(6 again) Read your answer to point (7) below; you’ve said it. Stage One, whatever it is, it is not an aircraft. A pilot will not make it more reliable, rather the reverse. He’d just be a liability. And I don’t fancy being the poor sucker who has to abandon ship (even if complete with parachute) at 200,000 feet. And which population centers were you planning to launching DH-1 near in any case?
(7) There is also no word about flying Stage Two in unmanned mode. But this is vital. As we have learned from the history of Shuttle it is clear that risking men on missions that don’t need men, such as delivering cargo pure and simple, is almost criminal. That’s apart from the obvious fact that an unmanned version could deliver more payload to orbit.
7. Unmanned aircraft are less reliable, unmanned space vehicles more so.
(7 again) You said it. So where’s the unmanned DH-1?
(8) Flying Stage One straight up and down again is an amusing notion, but an exceptionally inefficient way to get the payload into orbit. Existing launch vehicles follow the trajectory they do not for fun but because it is significantly more effective than this proposal. But what about recovering Stage One?……
8. The DH-1 is not a missile where max payload/min wt is important, for the DH-1 nothing matters but overall cost. The DH-1 losses only about 30-40% of it payload by flying the trajectory which is optimized for ease of recover of the first stage. The vehicle should not be compared to a optimized two stage but to a single stage. It has better payload and lower development cost than a single stage but retains much of the simplicity of operation of that of a single stage.
(8 again) Close, but no cigar. You’re on the button about the over-riding importance of cost. But all you’re doing with Stage One is getting Stage Two above the atmosphere. You could achieve the same result with the benefit of adding significant forward velocity by abandoning Stage One and strapping a couple or more solid rocket boosters to Stage Two; I bet if these boosters were discarded and so written off after each launch, that would still work out cheaper than your Stage One. And you’d probably double your payload to LEO into the bargain.
(9) Don’t bother recovering Stage One. By making it expendable a fortune would be saved, as it would not have to be built for reuse. Recovering and refurbishing the Shuttle’s solid rocket boosters almost certainly costs more than letting them sink and building new ones. Which leads naturally to…
9. The first stage is very simple and would need little or no refurbishment between flights. An expandable stages of the same size will cost 2-5 million even from a company like Space-X and of course if it is manned rated it will cost a lot more. An expendable stage also does not fit the proposed marketing plan.
(9 again) I think you’d find that NASA sold (or were sold) on the Shuttle’s SRBs on the basis that they would be “very simple and would need little or no refurbishment between flights”. If you still believe that— or if you are falling for the same line again— I’ve got a bridge to sell you.
You want simple? I’ll give you simple. Solid rocket boosters (I don’t mean the ones stuck on Shuttle) would probably be significantly cheaper that your Stage One. Go work it out. But I’ve another idea. Stage Two could be lifted almost as high as Stage One manages (certainly over 100,000 feet, possibly 150,000 feet) by slinging it under a gigantic helium balloon. Don’t laugh. Why not? The balloon is of course expendable, but that’s peanuts. And you don’t have to bother with Stage One or solid rocket boosters, etc. at all. You’d save a very considerable fraction of your costs, and that gives you ‘simple’ in spades. Go ballooning!
(10) Recoverable launch systems (RLS) will only become cheaper than expendable launch systems (ELS) when there is far more traffic than today. And as already pointed out, there is absolutely no assurance that low cost to LEO will deliver more business in a short enough time to prevent the RLS makers going bust in the meantime. If NASA had not been a government agency, I think it’s clear that Shuttle would have bankrupted them long ago.
10. I have to agree, for a RLV to be economical there must be a lot more traffic, but there must be a lot lower launch cost in order to get more traffic. It is a classic chicken and egg problem. The book presents one proposed solution to the problem. The market for a manned RLV might be different than the market for launch services, and if a number were sold, the market of services would grow.
(10 again) That’s why the way to go is, firstly a seriously big low-cost booster, which could well be a resurrected Saturn, to get serious amounts of hardware up there such as space stations Mars and Moon missions and colonies, perhaps even the start of solar power satellites and eventually, O’Neal-type colonies. For all of these, and others what will appear once we start building a serious space infrastructure, DH-1 is far too lightweight. But the BDB is not man-rated; there is an urgent need for a new manned vehicle to replace Shuttle as soon as possible. Maybe that will be where DH-1 will have a place, or something similar— except there’s not enough time to wait without another way right away. That’s why I favor resurrecting the Apollo command module reconfigured to take up to 6 people and launching with a Adriane 5 or similar.
You might call this plan “Back to the Future” J
(11) No-one should ever forget that today we have the absurd situation where sending a given payload to LEO by Shuttle costs several time more than it did using Saturn (in constant dollars) over a third of a century ago. Since the instruction to the Saturn engineers was to get the thing to work never mind the cost, and the Shuttle was justified almost solely on the basis of its cheapness compared with expendable systems, it’s abject failure is clear to all to see, or should be.
11. The situation today is hard to understand and it is not just the US and NASA that have problems nobody has found a low cost solution to the problem of space launch. The book is an attempt to look at the reasons why space transportation costs have not fallen very far and proposes a possible solution. More importantly the aim is to educate, and perhaps contribute to better design solutions in the future. No more NASP or X-33 or Buran, billions spent with no results.
(11 again) I commend your mission to educate, but (as you probably figured by now) disagree with your proposed answer. And yes, everyone has problems finding a low cost solution. But you must admit that NASA, with their Shuttle, takes the biscuit, with a so-called “low cost solution” that is actually several time more expensive than the ELV it was built to replace. It would be funny if it were not so pathetic, and so sad.
(12) Certainly the day must come when re-usable SSTO systems will be the way to go into space, but that day is most certainly not yet. What NASA ignored when lobbying for funds for Shuttle, and what people like TRC continue to ignore, is that at the present state of our technology, the cost of designing and building a re-usable vehicle makes such a so-called cheap system horrendously expensive. Indeed it is far more expensive than an expendable system in terms of the only measure that matters, which is cost per kilogram of payload to LEO.
12. The day is not yet, but the book argues it not the technology that is postponing the day, it is pursuing the wrong markets and wrong technology that give space launch a bad name. It is certainty true that a reusable vehicle is not cheaper unless the market for launch services is large maybe 10-1000 times larger than existing markets. The book tries to show one way that it might be possible to drive down launch cost with out a large transportation market, by selling launch vehicles. Only about 5% about of fiber optic cable band width was in uses in 2001. It may have made no senses to build so much bandwidth, but the fibers networks were built and cost for bandwidth are falling and demand is growing.
Something like that is need for space transportation.
(12 again) But if there is no large transportation market, who’ll buy your launch vehicles in the first place? As I said earlier, 2 or 3 vehicles would more than fulfil foreseeable demand for the total world market, and that includes the fraction which is military or otherwise classified that you would not get a sniff at any case. Also, from my back-of-envelope calculations, your LEO payload is not enough to boost the typical mass of today’s GEO satellites to GEO orbit, so bang goes another half of your market.
Late last year I had an article published in ‘Spaceflight’ which is published by the British Interplanetary Society. To give you a better idea of where I’m coming from, I’ll copy it here:-
Cheap Access To Space
By Jim Mangles
In 2003 we celebrate the 100th anniversary of powered heavier-than-air flight. The progress of flight over that time was impressive. Indeed, 50 years after Kitty Hawk, millions had flown, jet engines were in daily use, and the sound barrier smashed.
However we’re not likely to celebrate 2011 as the 50th birthday of manned space flight enthusiastically because there’s not likely to be much to celebrate. As things are, a few hundred people will have visited near-earth space and twelve landed on the Moon, but the last came home 39 years earlier. The most modern manned spacecraft will be a 40 year old design flying 7% as frequently, costing 16 to 33 times more than promised[1,2], and with a safety record that would ground any similarly performing aircraft[3]. Oh, and there’ll be a 15-year-late, over-budget space station with a tiny crew as it’s too expensive to have enough people up there to do more than keep it ticking over and, well, that’s about it.
Is this really the best we can do? Must we resign ourselves to a pathetic manned space effort that is both depressing for us, an insult to the early pioneers, and inspiring to no-one?
No! There is still time to make 2011 a worthy 50th anniversary.
The single most serious handicap facing manned spaceflight today is the extortionate cost of getting to LEO. If things had been as Shuttle had promised rather than delivered, it would be very different now. But now Shuttle’s failings make the need for a successor obvious and urgent.
Cheap access is the essential element missing from today’s arthritic manned space efforts, yet it is well within our grasp if we just looked in the right direction. Indeed, there’s no lack of proposed directions. Unfortunately almost all require long lead times, huge R&D budgets—and usually both. Shuttle itself was an expensive project that promised cheapness by frequent use. It failed to deliver for two reasons: firstly because it was technically impossible to turn a Shuttle around anything like fast enough; and secondly because there was just no demand for flights every few days at the prices Shuttle really cost.
I believe any attempt to replace Shuttle with a Super-Shuttle, space-plane or SSTO vehicle will fall foul of the same fundamental problems. This even applies to something so seemingly attractive as Bob Truax’s Sea Dragon Big Dumb Booster. Anything needing development from scratch should be put aside for now. It takes too long and costs too much; we’ll come back to build them later. Instead let’s get moving now with what we’ve got now.
But that’s a lot, if we just look.
Firstly, we should separate cargo launches from crew. It makes zero sense to risk people unnecessarily.
In 1968 NASA asked von Braun’s team to investigate development possibilities of the 118 tonnes-to-LEO Saturn V built for Apollo. Out of many ideas, here’s the biggest one—the V-D[4]. At 9,880 tonnes it’s a lot lighter than Sea Dragon’s 18,000 tonnes, but V-D could orbit 326 tonnes versus 450 tonnes. And no new ocean launch system is needed, just existing Florida facilities with a larger Transporter. Payload cost was estimated back then at $2,260/Kg, but there’s good reason to think a modern V-D would be cheaper by now—$1,000/Kg is a conservative estimate. At 10 to 20 times cheaper than Shuttle, this would cost less per mission than Shuttle.
Yes, Saturn is history, with drawings reputedly lost[5]. But even so we know we can build something like this; we did 36 years ago. In fact, we should be able to do better now, just so long as we can resist endless improvements. Good engineers know when to freeze designs.
An obvious question is, where do we find enough 326 tonne payloads?
Of course, we’d start with the 118 tonne version and grow with the traffic; still, who would want 326 tonne lifts? Apart from launching the entire ISS in one go, the answer is almost everything going up today, plus lots more that wouldn’t or couldn’t now. With vastly cheaper LEO delivery than anyone else, almost all today’s payloads will use what I’ll call Saturn-II. It can be used as a bus for many separate packages, including those for GEO and interplanetary missions.
And low cost delivery means lots more business. If it costs much less to orbit a package, the package does not have to be super-reliable as it’s cheap to replace. Thus the cost of space falls. Missions to Mars, Moon bases, and other over-ambitious manned missions today, now become quite reasonable.
Saturn-II is unmanned. So, we need a rapidly available, effective vehicle to get people to and from LEO safely.
I believe the safest and quickest answer is to rebuild Apollo; or rather, use the same geometry but completely redesign the interior[6]. It will need a launch vehicle, but suitable boosters are available today. For example, the USAF’s Titan 4 can hoist 17.7 tonnes to LEO and ESA’s Ariane 5, 18 tonnes. And there will be cheaper, better matched alternatives. Whatever is chosen has to be man-rated of course, but in any case Apollo-II will lift off with an escape tower, unlike Shuttle.
Apollo-II should be developed as soon as possible. NASA says 6 to 8 years, so it should be feasible in 2 to 4, as should Saturn-II.
These two old/new vehicles make it possible to build a future for manned spaceflight again, and they could be operational by 2011. However, there is one essential proviso. With its remarkable ability to bureaucratize, delay and vastly overspend, NASA must be excluded from all this.
Instead, I propose an entirely new CATS Corp. with the sole job of delivering people and things to LEO cheaply. Customers, including NASA, would pay for delivery just like they do for terrestrial delivery today. Then, from 100% Government ownership and initially using funds diverted from NASA as Shuttle runs down, CATS should soon become transformed into a normal company trading on the market.
At last space access would be cheap, self-financing and finally—glory be— beyond the vagaries of politicians.
[1] For simplicity, all prices are in 2002 US $’s
[2] The original mid-1965 Space Shuttle Mission Profile forecast first flight in 1975, building to 60 or more per year by 1978. If 60+ flights/year had continued to mid-2003, there would have been about 1,650 by then, with payloads costing $600 per Kg. In fact it first orbited in 1981 and had flown 115 times by mid 2003, including its 2 disasters. The true payload cost is hard to tie down, but lies in the range of $10,000 to $20,000 per Kg—far more than Saturn. Objectively, Shuttle has been a giant leap backwards.
[3] A man-rated launch system is one that is 99.8% reliable. Historically Shuttle is now 98.26% reliable and so technically is no longer man-rated.
[4] More information is available at [http://www.astronautix.com/lvs/saturnvd.htm]http://www.astronautix.com/lvs/saturnvd.htm
[5] Some in NASA say a complete set of Saturn drawings are held at the Library of Congress.
[6] More information available at [http://www.spaceref.com/news/viewsr.html?pid=9031]http://www.spaceref.com/news/viewsr.html?pid=9031
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But you *don't* need cheap launches for big stuff, for there'll be not much need for big stuff, at least in the beginning...
Say DH-1 is a given, you -expensively-launch *one* big 'empty' hull, and service/retrofit/man it *cheaply* with DH-1, AFTERWARDS... you can still make it economical.
Make, say, a Shuttle ET into a hotel/science station, big investment, only to get the empty tank up, sure, but if you can reach it cheap, once in orbit, that's not an issue, the big cruise-liners aren't cheap to build, but once they're built, the volume of *customers* make them profitable...
Hey, SIG (Space Island Group) could actually do what they envision, with a DH-1... Say 10 missions to outfit an empty tank, and then use it as a space-station/hotel...
And once there's a proven market or rather a *need* for more big stuff, investment in a heavy launcher will make more sense, too, and funding/loans will be much easier to get.
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I guess the question I would ask to Rocket Company is: how would you build anything in orbit? Would you launch DH-1s and convert their tanks into housing, as was originally planned for Skylab, then return the engines to the surface? I discussed this on another Forum in the New Mars Forums and think it would be hard to create any sort of destination in low earth orbit from 2.25 tonne chunks. How large of a unit could one get into orbit that way?
I have the same question for lunar explanation: can a 2.25 tonne plastic shell provide a useful habitat on the moon?
-- RobS
The short answer is: "No"
Building anything manned out of 2.25MT ton chunks is ridiculous... conversation reguarding which in "Earth to Leo revisited" page 4. If anything, a lunar module would probably be heavier.
I am also dubious of the "refitting of tanks" idea... the tanks aren't suited to micrometeoroid protection or long-term stress, not to mention that zero-G construction at the moment is essentially impossible. Astronauts don't build things, they assemble them.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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1. There is no market for dramatically increased launch capabilities.
It depends what you mean by ‘capabilities’.
If you mean more small payloads to LEO, like DH-1 offers, then I think you are right, there is no market. It is not coincidence that both ESA and the Russians have settled on boosters capable of placing about 10 to 20 tons in LEO, which makes it possible to put satellites of 5 to 10 tons in GEO—and that’s where the business is these days.
If you mean real heavy lift, see below.
2. For small 5-10k payloads Space-X, the Russians and Chinese may drive cost to $1000/lb.
Possibly, if they were going after the ‘tiny’ sector of the market. But they are not because there’s not enough business here.
3. Are large payloads need?
If you mean real heavy lift then of course, if we’re serious about building a space infrastructure, which means building a base on the Moon, another on Mars, space power satellites, space colonies—the whole shebang, in fact. Once there are the makings of a space infrastructure in place, then there may well be a place for a lightweight people-carrying SSTO (or near SSTO) like DH-1.
4. If large payloads are needed cost can not fall as easily, a few large expendable are not going to be low cost.
In fact, studies by TRW and others show that designing, building and launching a big ELV is not significantly more expensive than a small one. Only propellant cost goes up in step with the size of the vehicle, but propellant is a minute and insignificant fraction of overall mission cost. There is absolutely no doubt that the economies of scale are tremendous. Size matters, you might say.
This is what led Bob Truax towards his Sea Dragon concept, which must be the heaviest vehicle ever proposed to fly, intended to put 500 tons in LEO for about $500/lb. He also contemplated a larger (unnamed as far as I know) vehicle that could put 1000 tons in LEO for about $200/lb.
And of course the other beauty of ELV is that you don’t have to keep flying them to make them pay. They can just be built in the numbers required, when required,
5. If transporting people is still expensive, you still have a cost problem. New markets require lower costs for materials and people.
6. How low cost must fall and how little the investment needed could be, is the big question.
7. If the up front cost is 100's Billions it may not happen for a long time.
And if that’s the cost of being cheap, then ‘cheap’ will actually be enormously expensive. That’s the argument against anything fancy like space-planes, super shuttles, SSTO, etc. In the name of cheapness they would in reality cost a fortune.
Consider-- if we suppose it really took $100 billion to develop something like DH-1, and suppose 100 vehicles were sold in the first 10 years, and we wanted to recover development cost in that same 10 years (not unreasonable) then the development cost element of the sale price of each one would be $1 billion, before you did anything else like building the unit for example. If you had to add on financing cost, that might almost double it. So you could find you have to add almost $2 billion to each unit’s price before you even start building it. This might just possibly affect the number you could sell, don’t you think? It might just possibly affect the price you would have to charge per lb of payload if you gave up trying to sell the vehicles (due to the lack of buyers) and ran the lifting business yourself, don’t you think?
And if as I suggested earlier, the world market for a vehicle like this is probably at best only 2 or 3 anyway, then you’d be looking at a development plus financing cost of something like $60+ billion each.
I fear you’re going to have very few customers at the price/lb you’d have to charge. You’d make Shuttle look cheap! So you don’t even need three vehicles because there would not even be any business for just one… this is becoming a scheme that would bankrupt even Bill Gates.
To be fair to TRC, they don’t talk about $100 billion and neither do I. But see my earlier post, where I work out why their true cost/lb to LEO will more probably be $3,500 rather than the $200 they talk about themselves.
8. If only 1-5 Billion it will probably happen soon even if the first few tries fail.
It will not be that cheap, as I have shown earlier. But even at $1 billion it will fail because the market does not exist.
9. The Rocket Company tries to show that small payloads are sufficient, and that the cost of people and materials can be lowed together.
10. The solution proposed is to create a market for a small manned almost single-stage vehicle.
It does not exist, and will not exist ever, unless there is a space infrastructure first.
Think of the space infrastructure as the rough equivalent of the transcontinental railroad, plus San Francisco at the far end as a destination. Without that, it would have taken forever to settle the west.
Or look at it this way:
It’s clearly profitable for an airline to operate a regular service that offers to fly passengers between (say) New York and Los Angeles. It is just as clearly not profitable for an airline to operate a regular service that offers to fly passengers between (say) New York and the North Pole. Why no regular service to the North Pole? Simple. There’s nothing there. Until there’s something there, space is up against the same problem. What’s needed first is a space infrastructure, and DH-1 is far too itsy-bitsy to deliver one.
11. And the viability of the proposed solution to the high cost of space launch, hinges on two points, that there is a market for a manned RLV which cost around $250 million.
12. And that such a vehicle is technically and economically feasible.
Technical? Yes, although there are questions, such as why a pilot in Stage One?.
Economic? No.
I think the last point is one on which reasonable people will disagree, and I think the only way resolve the disagreement is to build the DH-1 or something like it.
So, are you ready to put up the $5 billion to find out?
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Launch Vehicle tanks weight about 0.5-1.0 lb/ft^3 so using an inflatable structure or an assembled tanks from parts, 5000lb is a habitation structure of about 5000-10000 ft^3.
Further the DH-1 is designed as will be discussed in later chapters to be flown with a max first stage fuel wt and an optimal trajectory can but up about 12,000 lbs in LEO at a higher cost.
If routine assess to space is available at lowcost we can learn to assemble large structures in space.
The south pole station was built with C-130 with a payload of only 12,200 kilograms to the pole.
There is no market? IBM thought the market for computers was what 8-12. Who said there is no market for computers in the home? $100 billion was spent on fiber optic cables and we are using what 5% of it. New markets do arise if only some one build new capability.
The Saturn V and the Energia were not low cost. Beal aerospace spent $200 million on a big dumb booster and gave up. No one has ever built a big dumb booster. And those who have tried know it’s not so easy. Why did Space-X, who has people from TRW go with a pump fed stage.
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Launch vehicle fuel tanks are not habitation modules... anything that people live in should be substantially heavier and/or shielded to resist micrometeor impacts and/or radiation. Then you have to also consider the docking hatches, which are pretty heavy with the adapter gear and sturdy high-torque construction, and all the attach points for things, plus plenty of other usual stuff that induces weight creep.
And I don't think most people realize just how hard it is to construct, not assemble, things in orbit. Let me give you a little taste...:
[http://www.astronautix.com/craft/issunity.htm]http://www.astronautix.com/craft/issunity.htm
"More than 50,000 mechanical items, 216 lines to carry fluids and gases, and 121 internal and external electrical cables using six miles of wire were installed in the Unity node. The detailed and complex hardware installation required more than 1,800 drawings. The node is made of aluminum."
This is for the little US Node-1, one of the smaller pieces of the ISS with a volume (sans adapters) of around 3000sqft. It weighs in at 11,600kg.
Astronauts do not build things in orbit. They assemble things in orbit built on Earth. This is not going to change any time soon even if you do lower the price of launch an order of magnetude or two.
Also, I am a bit puzzled at how your launch vehicle can have 240% better performance at a "higher cost" trajectory... anyway, that is still much too small. 5,000lbs is simply nothing for building stuff... I wouldn't start talking manned space station anything until it hits 20,000lbs.
And i'm going to have to weigh in that without a more concrete business case than "build the bridge and people will cross it" I doubt funding will be forthcoming... there is simply nothing you can do profitably in space with such a small vehicle with todays technology except ferry up bulk supplies to LEO... and for that, you need someplace to fly it to first.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Yes, Unity has "More than 50,000 mechanical items, 216 lines to carry fluids and gases, and 121 internal and external electrical cables using six miles of wire were installed in the Unity node. The detailed and complex hardware installation required more than 1,800 drawings. The node is made of aluminum." But did it HAVE to have all of that, or did it have this complexity because it was possible and because the thing was so dang-blasted expensive to launch anyway?
And "Astronauts do not build things in orbit. They assemble things in orbit built on Earth. This is not going to change any time soon even if you do lower the price of launch an order of magnetude or two." Who says? I am old enough to remember Skylab, and that WAS the original plan for Skylab; launch the mass with a Saturn I booster, go inside the tank and convert it to housing. If NASA had planned to convert a fuel tank into a space station in 1971, why can't we do it now? They switched when a Saturn V became available after Apollos 18+ were canceled. Clearly, the original plan did not include installation of 6 miles of wire or anything like that.
Yes, we will have to consider debris strikes; this wasn't much of an issue in the 1970s. Possibly a big kevlar umbrella could be opened in "front" of the nodule, just as Skylab astronauts opened an umbrella sunshade to protect Skylab from overheating.
To give people a feel for 5,000 to 10,000 cubic feet; a cylinder 20 feet (6 meters) in diameter and 20 feet (6 meters) long has a volume of 162 cubic meters or 5,717 cubic feet. That's 22% larger than the Unity Module (4 meters in diameter, 11 meters long, 132 cubic meters). The Unity Module's mass of 11,600 kg includes docking adaptors.
-- RobS
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Launch Vehicle tanks weight about 0.5-1.0 lb/ft^3 so using an inflatable structure or an assembled tanks from parts, 5000lb is a habitation structure of about 5000-10000 ft^3.
-- I don’t fancy living an orbiting balloon. How are you going to protect it from space debris and asteroidal collision, for example? Or what happens during a Solar flare? Better stick to using balloons nearer sea level as I suggested earlier, as a (much cheaper) alternative to Stage One.
-- Anyway, you have just described an empty balloon. Don’t you think it might need some things in it to make it habitable?
Further the DH-1 is designed as will be discussed in later chapters to be flown with a max first stage fuel wt and an optimal trajectory can but up about 12,000 lbs in LEO at a higher cost.
-- This sounds very odd, from what I read of the book so far. I suppose an all-automatic mission would help, but not that much surely? Why would you ever fly it with LESS than max First Stage fuel and optimal trajectory in the first place?
If routine assess to space is available at low cost we can learn to assemble large structures in space.
-- Firstly, it might be smarter to learn how to assemble large structures in space first, and only then think about routine delivery of itsy-bitsy payloads.
-- Secondly, the cheapest and most practical way to assemble large structures in space is to assemble them down here and then orbit them pretty much completed, using a BDB.
The south pole station was built with C-130 with a payload of only 12,200 kilograms to the pole.
-- 12,200 kg is about 5.35 times the DH-1 payload.
-- Assembly at the South Pole has its difficulties, but vacuum and zero gee are not among them. And there are still no regular scheduled commercial flights to the South Pole any more than to the North Pole. My point remains unanswered.
There is no market? IBM thought the market for computers was what 8-12. Who said there is no market for computers in the home? $100 billion was spent on fiber optic cables and we are using what 5% of it. New markets do arise if only some one build new capability.
-- Moore’s Law does not apply to space flight. Computers are an exceptional case. The price and demand curves for other things have not followed the almost unique example of computing. And if only 5% of fiber optic cable capacity is used, that’s a classic example of over-provision. Imagine how much cheaper it would have been to install a network that actually matched requirements.
-- New markets do arise if someone builds the capacity-- occasionally. “Build a better mousetrap and the world will beat a path to your door.” Usually they don’t and the capacity (or mousetrap) builder goes bust.
-- Of course, a large part of your trouble is that you don’t offer a better mousetrap. 5Klb in LEO is far too lightweight to boost a useful payload to GEO, and even the 12Klb to LEO you mysteriously pulled out of your hat earlier is not enough. But GEO is where people want their satellites to go. That needs at least 20Klb, better still 30Klb.
The Saturn V and the Energia were not low cost.
-- Compared with what we have today, Saturn V was, especially compared with Shuttle. If it was being built again today, Saturn V would be the cheapest launch platform around by a mile. And if you know how much Energia cost, you must be a rare individual. I’ve been trying to find out for some time; certainly the Russians are not telling.
Beal aerospace spent $200 million on a big dumb booster and gave up.
-- Beal’s vehicle was not a BDB. For a start, it was not nearly big enough, by a long shot.
No one has ever built a big dumb booster. And those who have tried know it’s not so easy. Why did Space-X, who has people from TRW go with a pump fed stage.
-- No one has ever tried, so how can they know?
-- No one has ever tried to build a reusable either, so how do you know it’s easy, or cheap, or both? (Except Shuttle—which is really only a semi-reusable, or more accurately, semi-refurbishable—if you insist. And that was and is neither cheap nor easy… to say the least.)
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JimM: You wrote, "I think your question is based on a misconception, which is that a satellite in GEO is stationary. But it is not, it is orbiting at exactly such a velocity that is keeps pace with the surface of the earth approximately 5.6 earth radii below it."
Well, not quite, but to tell the truth, my premise was a gut feeling that: to accelerate to LEO orbital velocity and then decelerate to GEO orbital velocity would use more fuel, than accelerate-only to GEO orbital velocity. It seemed only logical, but my motivativation wasn't that. It pleased me to accept it as a lucky bi-product--of launching-direct to GEO for the purp[ose of simplifying assembly-in-orbit, using remote-presence robots as astronaut substitutes. So, even if the total fuel requirement for a Mars departure from GEO turned out to be more than from LEO (still hard to believe) the simplified assembly would be worth it, for my scenario.
Thanks a lot for the trouble went to to. I'll do a printout for future reference.
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"...but to tell the truth, my premise was a gut feeling that: to accelerate to LEO orbital velocity and then decelerate to GEO orbital velocity would use more fuel, than accelerate-only to GEO orbital velocity."
However, as I hope I have shown, transferring from LEO to GEO orbit does not involve decelleration, but instead acceleration.
Remember, velocity is a function of speed AND direction, not speed alone. In the special case of circular velocity, which is what we are looking at here, radius can be said to stand in for direction (to simplify things) and the radius of a GEO orbit is clearly much greater than that of a LEO orbit.
So, speed may be lower, but velocity is greater.
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Umm, velocity is a directionless vector, it doesn't matter which way it's going. It takes accelleration to go from LEO to GEO because you're climbing out of Earth's gravity well. When in orbit, moving towards Earth will cause you to accelerate, Moving away from Earth will cause you to decellerate, accelerating along your orbit will cause you to move out and decellerating on your orbit will cause you to fall inwards.
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How to make A 10,00ft^3 habitat
first inflatable shell 5000lbs
second inflatable shell inside first shell 5000lbs
2x5000lb of foam between the shells
airlock module 5000lbs
total 25,000lbs
Many thing from cars to rocket engine weigh less than 5000lbs. 5000lb is a pretty big module, such modules could be designed to be assembled in space with no small parts like screws or bolts need.
Most payload in the future is going to be propellants, supplies like food, and people maybe 90% if the rest takes a bit of engineering to get it down to 5000lb modules so be it.
As to the market-
Forsyth had once heard Herbert Kromer, a Nobel Laureate in physics, expound his favorite proposition or lemma, “The Futility of Predicting Applications,” which stated that “the principle applications of any sufficiently new and integrated technology always have been and will continue to be applications created by the new technology.” Put simply, with any sufficiently new technology, we just don't know what use it will really be until after it is brought into being. Forsyth believed that low-cost space transportation – and he still wasn't sure what “lost-cost” was, perhaps $500 a pound, $200 a pound, $50 a pound, whatever – would lead to more than incremental change. It was going to be one of those innovations which would have a big impact on life as we know it. Just how big, he really couldn’t say. And whether the eventual applications included space tourism – which had become popular of late, or solar power satellites, or space colonies, or material processing, or extraction of resources from the asteroids, or something completely undreamed of, the trick was to find a way to bring about low-cost space transportation before you knew what to do with it.
The last forty years had seen a lot of futile effort by space enthusiasts to find the one magic product or market which would justify building a truly commercial space industry. Well, it hadn't been found and frankly, he was tired of waiting for it. And if you accepted Kromer's lemma, it couldn't be done that way anyhow. Even if you guessed correctly what it was that would create a huge growth in demand for launch services as costs came down, that demand wouldn't – and couldn’t – come into being until the cost did come down. What was needed was the classic “self-reinforcing spiral” that Bill Gates knew so well.
The Rocket Company Chapter 3. The Quote of Herbert Kromer is from IEEE Spectrum in the last couple of years.
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Building a mode of transportation without profitable destination is economically illogical, a catch 22 if there is one.
I agree. For years, I have been ranting about chickens and eggs here at NewMars. . .
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"I would like to add that Kromer is a physists and not an economist... nobody will invest in such a vehicle unless it has a purpose. This is a pretty solid law of economics, that the certainty of return on investment is a substantial barrier to said investment. Building a mode of transportation without profitable destination is economically illogical, a catch 22 if there is one."
-- I presume you meant to say, "LACK of certainty of return…" In which case, hear, hear. I was trying to make the same point whan I talked earlier about scheduled commerical flights to the North Pole, or rather the lack of them.
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Yeah, sorries my year of economics talking, shoulda clarified.
I would like to add that the launcher cost for most space projects is only a portion of the cost of the actual payload usually. The cost of making a large object out of many payloads will be much greater compared to a large object launched in few payloads by nature of the need for assembly. This directly counteracts the decrease in launch costs, and would be a much bigger problem for the DH1 with its really really small payload.
5,000lbs really is not much material... all those zeros make it sound big, but even the Gemini one-and-a-half man capsule weighed almost 9,000lbs and the Apollo CM without the service module - just the capsule - weighed over 13,000lbs.
You can't send a manned vehicle up in two launches!
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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5,000lbs really is not much material... all those zeros make it sound big, but even the Gemini one-and-a-half man capsule weighed almost 9,000lbs and the Apollo CM without the service module - just the capsule - weighed over 13,000lbs.
The Apollo Command Module was 30.3 MT at launch. So it was about actually 67,000 lbs, or 14 launches.
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Not sure i'm down with the whole giant balloon idea... It may work just fine for small payloads to LEO, but may present scaleability concerns to lift a rocket able to put five tons to GEO.
-- Well, the balloon idea occurred to me as I considered what TRC wants Stage One to do, which is basically be an elevator: straight up, then straight down again. So, why not use balloons, I thought, and forget about getting the balloon back for reuse?
-- Now it’s true Stage Two would be imparted enough vertical momentum by Stage One to keep it from falling back into the atmosphere before it had reached enough horizontal velocity to stay up on its own, but you could compensate for loosing that if using balloons by firing Stage Two at, say, 10 degrees up from horizontal until it has the necessary velocity to stay up, But still… anyway, TRC’s flightpath is a hack-handed trajectory for getting to orbit. Straight up, then straight alongways. Yeh. I don’t think.
I think there are only two routes currently practical to making a true RLV, barring the introduction of a next-generation super composit and/or the perfection of friction-preheated Scramjets.
-- Don’t hold your breath waiting for these scramjets. I’d reckon we could be up to 50 years away from a serious application like that.
Option #1: Heavy TSTO spaceplane, …..
-- As I see it, the overwhelming requirement is not SSTO, spaceplanes, or anything like that, but Cheap Access To Space – CATS. As I have been known to say before now, if that means chariots drawn by squadrons of white swans, or using the rising morning dew to lift your spaceship, I don’t care.
-- All that matters is cheapness. Everything else is just a distraction from the single and sole essential requirement, which is CATS. In this, technically sweet spaceplanes using yet-to-be-invented technologies are nothing more or less than a pointless distraction. Any and all of them would cast billions and billions to develop, take decades to get operational, and cost the earth to operate. We’ve already been that way. It’s called ‘Shuttle’.
-- The thing is, we have all the technology we need right now. All we have to do is stop trying for something better and just get building.
-- Always remember, the perfect is the enemy of the good enough.
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Shuttle is a disaster, but it isn't a spaceplane; its a conventional rocket with an airplane-shaped upper stage with a trio of experimental rockets in the back. It was all that could be afforded at the time, so a truely reuseable vehicle was abandoned. In fact, I believe its quite possible that the Shuttle debacle came about because it would be a gravy train that its been for an army of engineers, which has been rolling for nearly 30 years and will keep an entire generation of them employed from college to retirement... This, Shuttle's true purpose, has suceeded beyond their wildest dreams, each deadly disaster reinforcing the conviction to keep flying no matter what.
Cheap access to space with reasonable masses, volumes, and reliability are very important, but with conventional expendable rocket technology will eventually reach a high minimum cost due to the fact that you don't get the big rocket back. The economics of reuseability are not a pipe dream, a true RLV that can deliver substantial masses on a regular basis without needing a support staff of 100,000 will probably win out in raw costs over a regular rocket. Somthing like the DC-X or a modernized Shuttle LSA that could deliver 10MT to orbit weekly can move 500 tons a year for years with only one vehicle. Expendable rockets will never be build-in-your-garage "simple" or "cheap" or "dumb" and whatnot, even SRBs... they are complex and expensive contraptions, and throwing them away costs a fortune. This is okay for a low flight rate where development costs and availability are at a premium, but it will one day be a brick wall to the development of space.
Do we need this today? No... Would it be nice? Yeah, especially for delivering cargo/fuel/crews and for making us more competitive in the launch market vs. cheap foreign boosters. Will we need it later? Definatly... The technology is not that far off, we could do it today, though it would be a large investment.
And of scramjets, ehhh I don't know about 50 years... the USAF thinks they can make a hypersonic bomber in a decade or so using scramjets, though it is a valid question if they can reach the Mach 20+ region needed for efficent spaceflight any time soon.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Shuttle is a disaster, but it isn't a spaceplane; its a conventional rocket with an airplane-shaped upper stage with a trio of experimental rockets in the back.
-- Shuttle isn’t a spaceplane, true. What it is is a rocket that takes wings up with it for the sole purpose of bringing them back again. The Flying Brickyard is really an abortion of a vehicle—a horse designed by a committee, which is known as a camel.
-- It would have been far better to stick with ELVs, like the Russians did (and have shown was the correct route) as with Shuttle we just got ourselves the worst of both worlds.
-- For as long as I can remember, it has been a sort of article of faith that RLV must be cheaper than ELV. The thing is that it is Just Not True! There are several reasons why it is Just Not True, but they really all boil down to what you might call the Concorde Syndrome.
-- Concorde was recently taken out of service because it was proving too expensive and difficult for British Airways and Air France to maintain in operation, despite effectively being given the aircraft free by the government who had swallowed the entire development and construction costs. This was the only way any airline could afforded to fly Concorde; at true cost (that is, including development and construction amortisation) no airline would have flow it for even one day. A large part of Concorde’s cost problem was its very short production run. If two or three or more hundred Concordes had been sold then there might have been a very different story.
-- So has it been for Shuttle. If there had been a hundred or more Shuttles required; if the thing had flown on time; if it have been designed and built on cost; if there had been anything like the demand that NASA had forecast; if it had been able to be turned around and re-flown with the frequency forecast… but none of that happened. The sad truth is that the whole concept was based on a fallacy, and to this day most people don’t seem to see that.
-- Reusable systems (be they spaceships, aircraft, or anything else) are only cheaper than expendable systems if they are going to be used frequently enough or if enough of them are needed, or both, to absorb their very much higher design, development and construction costs. NASA based their justification of Shuttle on all the wrong assumptions, in particular that the traffic demand would justify reusability. In other words, “Build them and they will come.”
-- However the traffic never came close to justifying its costs, and so the Shuttle is inexorably inflicted with the Concorde Syndrome. In large measure due to it costing so much to develop, the Shuttle starts out into the marketplace with a price tag for lb/LEO very much higher than forecast, which apart from any other reason resulted in much less business than forecast. So the traffic does not cover the vehicle’s cost, hence the vehicle’s cost/lb go up. So there is even less traffic, and the cost/lb goes up again. As a result there is even less traffic … Today we have the absurd situation where sending a pound to LEO by Shuttle costs (in constant dollars) several time more than it did using Saturn over a third of a century ago. Since the commission to the Saturn engineers was to get the thing to work and never mind the cost and the commission to the Shuttle engineers was to build a system that cost much less than Saturn, it’s abject failure is clear for all to see, or should be.
-- All-in-all, Shuttle has proved an excellent way to throttle the US manned space programme. To go for another so-called cheap re-usable launch system that would inevitable end up being extremely expensive, unreliable and late would probably kill off US manned space flight completely.
-- Things are that serious. Learn the lesson that RLVs are NOT cheaper than ELVs or die as a spacefaring nation. That serious.
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A "railroad to space" when you get your train back (and to the station to boot!) would be pretty nice for getting lots of people and stuff into orbit; it worked pretty well here on Earth for the American development of the West.
-- Because a transcontinental railroad was the sine qua non of 19th Century western development does not automatically make spaceplanes the sine qua no of 21st Century space development. I would expect spaceplanes, VTOL SSTO vehicles, or whatever to develop naturally to fill an existing market need when that market has been developed by other means.
-- It would be… no, it has been extremely foolish of us to hang the entire future of manned space on the performance of marginal “reusable” semi-spaceplane that has effectively to be refurbished after each mission. I hope we are all agreed that the Shutle has been an abortion that has only one clear achievement under its belt— the stalling of manned space for about a quarter of a century.
I disagree that space ships are "not aircraft" or whatnot, they very much are, the gravity & atmosphere of the Earth, …
-- That’s like saying an aircraft is an automobile because it spends part of its life traveling along a paved surface that resembles a road; or an ocean-going surface ship is an aircraft because most of it travels through the atmosphere, not the ocean.
… you aren't going to launch fifty 5MT satelites to GEO on a Sea Dragon
-- Why ever not? Sea Dragon puts the 50 in LEO, which are then launched on their transfer orbits to GEO one at a time so as to match their station at GEO. It’s simply an extension of the existing method used to launch two separate GEO-bound satellites launched by one booster such as Ariane V. It’s quite easy, actually, and happens all the time.
… and what if you only need to move 200MT?
-- Two possibilities present themselves.
-- First, wait until other payloads come along to take the total manifest up to 500 tons. This would be the cheapest option.
-- Second, pay a surcharge to cover the cost of the missing payload so your 200 tons can be launched right away. This would obviously cost more than the first possibility, but is still much cheaper than any available alternative. (Actually, it would alway be a good idea to bring the payload mass up to 500 tons with water. Water will be in perpetual short supply and highly saleable up there in LEO, I'm sure.)
-- Of course, if the only alternative was Shuttle, say, the 200 ton payload would have tp be broken down into Shuttle-digestible chunks—seven trips, perhaps? Then if it was a spaceplane, none of which seem to be able to handle payloads exceeding 10 tons, that would mean at least 20 trips. And of course TRC’s DH-1, with its itsy-bitsy 5,000lb payload, would need to make 80+ trips. (And you could be 300 tons of water down. What do you bet you could sell that water up there for enough to offset the cost of launching your own 200 ton payload. Effectively, FREE to LEO!)
-- Then you’d have to add on all the additional trips needed to get the assembly crew up, provide them with living accommodation up there, rotate them up and down (doubling the number of trips by Shuttle, etc. would be a reasonable guess) Of course none of these extra trips are needed with BDB … Sorry, one big lift wins by a mile, even if the launch vehicle was half empty.
More routine flights …
-- Until there is enough demand, what for?
… with smaller vehicles is a requirement for this sort of travel …
-- Given that BDB is unmanned, a small man-rated vehicle and launch system is indeed what is needed.
… nor is using a capsule + parachute route good enough either for people...
-- Why not? As a crew recovery system, it’s got a better safety record than Shuttle.
… the vehicle has to return to a launch site in essentially flyable shape quickly and reliably with short turn-arounds for large scale manned flight…
-- What large-scale manned space flight is there going to be until BDBs put the infrastructure in place up there on the first place?
… and not all payloads are big.
-- So they go onto the manifest for the next available BDBs ‘common carrier’ bus. (It’ll be so cheap it should capture just about all the existing launch market and create an even bigger one by virtue of its cheapness.)
2: Will never be routine enough...
-- That’s the point of BDB. It isn’t routine! It’s launched when it’s needed, not according to a schedule like an airliner.
when considering large spans of time with lots of available business, the development cost becomes much less relivent versus operational costs,
-- Only if you have the traffic. Shuttle proved you can’t count on the traffic just turning up. My point now is that there never will be the traffic until you build the space infrastructure, and that’s where you need the BDBs. Trying to build the infrastructure in penny pieces is just ludicrous. If you doubt this, look at the farce which is ISS.
… launching of large expendable vehicles will always be a signifigant undertaking that cannot be simplified as much as a good RLV could on a per-flight basis …
In fact I don’t see why not. A real BDB like Sea Dragon would be vastly simpler vehicle (that’s what the ‘D’ stands for) than any conceivable spaceplane; so it’s far less likely to go wrong.
, if for no other reason that RLVs are smaller and you must build a new vehicle for each flight.
So the RLV will be so few in number you’ll never get the economies of large scale production runs; it’ll be like each one is hand-built cost-wise. Meanwhile the ELVs will get these economies from larger production runs, and anyway it’s a much simpler vehicle to build.
I also think that because of all the stuff that is needed for a large launcher, that it will probably never be able to trump a true RLV fleet in operations:
-Saturn V/Sea Dragon/EELV/etc... Large assembly structure because of the volume of fuel required for weight efficency. Large roll-out vehicle or ship, launch table, and careful allignment thereof. Often requires a large launch skyscraper really and definatly a large assembly building. (Shuttle also requires all these things, which makes me deem it not an RLV.) In order to increase launch rate, many of these facilities will have to be duplicated and operated in parallel.
-- Sea Dragon would be built in a shipyard and launched from the sea, not unlike a underwater-launched missile, except it would launch from the surface, so none of this new support stuff would be needed. Saturn-V would take back the VAB and Pad 39. It’s all there waiting, once Shuttle gets kicked off the site.
RLVs can scale in parallel easier than ELVs, so in the long run they can be cheaper per-pound than even the biggest of ELVs.
-- True in principle but pointless in practice, because the Business Will Not Come. Instead it will just turn out to be a second fabulously expensive failure, like Shuttle—and this time, it would killed manned spaceflight for good. Unless, of course, BDB’s enable the space infrastructure to be built first.
If you can make a space RLV able to carry 20MT a flight 100 times a year, then Sea Dragon would be competitive... but if you had twenty such vehicles or whatnot, then Sea Dragon or whatever megarocket wouldn't be able to keep up.
-- Again, this scenario is based on the better mousetrap fallacy. The cargoes did not turn up for Shuttle and they will not turn up for your RLV until there is somewhere to deliver them to. For that, your RLV will have to wait until BDB has enabled such places to be created.
I'm also dubious of any ocean-recovery mechanism in general...
-- Sea Dragon’s recoverable First Stage, I remind you, is basically a sturdy pressure vessel built in a shipyard. It is not a series of relatively flimsy rings held together by O-rings, etc. Anyway, recovering Stage One is not essential for Sea Dragon viability.
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