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What wrong with the DH-1 heatshield? Every reentry vehicle except the shuttle uses an ablative heat shield. The ceramic blanket used by the DH-1 is based on the work of Paul Sawko of NASA Aimes for the shuttle. see US Patents 5,657,795 5,451,448. The ceramic blanket alone which can handle 2,500 F can just about handle the max DH-1 heat loads of about 2600-2800 F which are relatively low because the DH-1 has no sharp leading edges. Add something to the ceramic blanket which holds water as a hydrate as suggested in the book and you have ceramic heatshield which is light weight flexible and can take the heat and should stay well below 2,500 F.
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.
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.
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.
(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.
(3) In that light, TRC's promise of $200/lb to orbit (which, allowing for inflation, is just about the same as NASA’s $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.
(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.
(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.
(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.
(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.
(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 maned rated it will cost a lot more. An expendable stage also does not fit the proposed marketing plan.
(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 maned RLV might be different than the market for launch services, and if a number were sold, the market of services would grow.
(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.
(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 the 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.
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