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That number rings a bell… yes… yes… $100bn is the cost of the ISS.

In that light, SPS is so cheap how can anyone say no?

But that's only part of it, as I pointed out.

Any anyway, who says it's 100 times more expensive?

Yes, it certainly would be pricey to start with, but with real mass production (in space, on the moon) with real low-cost heavy lift (yes, BDB!) and all the rest of it, it won't be more expensive for long.

And we have the first real breakthrough into space on a sustainable, economic basis.

(Serving sugestion:- don't let NASA near this.)

Yes, all of the above, and we can see already why DH-1 will fail on at least four out of these five conditions.

The 'better mousetrap' or the 'build it and they will come' pitch will not do and certainly will not convince anyone, such as a bank, billionaire, etc., in the project-funding business to invest a single penny. (Billionaire do not normally becoe billionaires by being carelss with their money) I'm far from being in the project-funding business, and certainly TRC does not convince me, even though I ardently want space travel moving forward again.

With TRC, the wish is father of the silly idea.

I hold the veiw that until manned spaceflight can be conducted for profit, it will never get anywhere.

The most worrying thing about manned spaceflight today is that we have to go around thinking up reasons why people should invesst money in it. Most advanced technologies have obvious and profitable applications so the venture capitalists and banks are normaly not so hard to convince. But apart from what are really nich applications like weather and TV satellite in GEO-- where the venture money has been forethcoming--there are almost zero examples of space being used to make money.

Unfortunately weather and TV satellite in GEO do not require people in space; indeed they would probably be more of a nusance than a help Similarly, they don't need RLVs either, as this thead has been showing recently.

There are only two COMMERCIAL, FOR PROFIT ideas I've hear mention of that sound as if they might just be good reasons for manned spaceflight.

Unfortunately, both have serious, possibly killer, flaws.

1: Space tourism.

Doubtless there is a market of very rich people who would pay millions, and an even larger group of not-so-rich who would pay many thousands, for a journey into space and a stay at a spce hotel, and cruises around the moom, and so on.

(Yet fundamentally, this is another 'build it and they will come' project--like Shuttle, or even DH-1. Worrying, don't you think?)

However it would take literally tens upon tens upon tens of billions to create a spce infrastructure that caters to this need. I can't see any capital provider looking at such a venture seriously in the conceivable future. Taking space's history of cost escallation into account, he'd think somewhat along the following lines--

Expenditure
Projected capital cost: $30bn (2004 money)
Development time: 20 years
Probable actual capital cost: $60bn (2004 money)
Interest accrued on capital (by completion) at 10%: $60bn (2004 money)
Debt at completion: $120bn (2004 money)
Annual capital repayments over 24 years: $5bn (2004 money)
Average annual interst on debt at 10%: $6bn (2004 money)
Annual operating cost: $6bn (2004 money)

Thus, average annual expenditure for first 25 years: $17bn (2004 money)

Income
Market A, the super-rich: 1000 @ $5M = $5B per year (2004 money)
Market B, the less rich: 10000 @$500,000 = $5Bn per year (2004 money)

Thus average annual income for first 25 years: $10bn (2004 money)

Thus average annual PROFIT/(LOSS): ($7Bn LOSS) (2004 money)

Of course, as the venture accrues debts, the debt interest due would grow, so things would just get worse year by year. In 25 years, the accrued losses and interest on them would have amounted to somewhere around $300bn. The original $60bn would be as nothing before this mountain of debt. The only question is, when do we recognise the business is bankrupt and close it down? Obviously the logical day to do that is the day before day One. Strangle it at birth, IOW.

So let's see. I'm supposed to find $60bn to finance this venture, which won't be operational for 25 years, then watch another $7bn (plus interest) indebitness increase annually for another 25 years until I owe something like $300bn. Is this someones idea of a joke?

… at which point you would politely be shown the door, with the parting words, "Don't call us,we'll call you."

2: Space Power.

As we face an ever-growing risk of a serious disruption to oil supplied, the practicallities and the economics and the necessity of SPS seems poised to become much better than they have up to now.

SPS is a project that would cost far more than space tourism to get started, but sands every chance of make profits in the long term. Nowever the money needed (2,3,4,5 hundred billion dollars?) is way beyond the pockes of private investors. It HAS to be funded by government. That's the difficulty, and it's not minor.

The side effects are good, however. Apart from what it does to get out of the clutches of OPEC, it also gives us a solid, enduring space infrastructure as a major spin-off. And space tourism might be economic too, as another sort of spinn-off.

Or the NASA quote is high. NASA is not famous for doing thing cheaply.

This was  (is) not obvious from a search of TRC for specific impulse values. I see the RL-60 is said to manage 468 Isp(vac) in its Martian version, but that was not what I was looking for before, and by the time TRC gets to its Mars mission, it’s fast heading towards cloud-cuckoo land for other reasons anyway.

In fact, TRC mentions the RL-60 several times earlier without mentioning its performance  at all!

An exhaust velocity of 4400 mps gives an Isp(vac) of 447.
An Isp(vac) of 433 gives a exhaust velocity of 4250 mps.
An Isp(vac) of 465 gives a exhaust velocity of 4550 mps.
Since the SSME only manages 450 or so, then 433, which I remind you was derived from the other information supplied, seemed (seems) perfectly reasonable—and 465 did (does) not.

OK, so…

delta V = Isp(vac)*g*ln(MR) = 465*32.2*ln5.8 = 465*32.2*1.758 = 26323 fps

…which is just about enough to almost get clear of the super-marginal  area for orbital flight, but only if we ignore all the other problems I pointed to.

Anyway, it starts to get into real trouble when the other problems concerning getting DH-1 to orbit that I mentioned but put to one side are brought into play.

For just ONE thing, the high-altitude atmosphere DH-1 has to fly through at the start of its Stage 2 powered flight is going to have the same sort of effect as a 2 to 4% engine performance degradation. That is to say, it is equivalent to an Isp(vac) fall-off  between 9.3 and 18.6, giving an effective Isp(vac) of between 455.7 and 446.4.

Let’s get more precise:

(1) delta V = Isp(vac)*g*ln(MR) = 455.7*32.14*ln5.8 = 455.7*32.14*1.758 = 25746 fps
(2) delta V = Isp(vac)*g*ln(MR) = 446.4*32.14*ln5.8 = 446.4*32.14*1.758 = 25223 fps

In other words, the higher Isp(vac)  makes no fundamental difference.  There is far too little spare delta V for the other requirements and reasons I listed before; it is still super-marginal for achieving orbit.

THUS: DH-1 is not a viable launch system with a 5,000 lbs payload, or any payload close to it.

I can think of a number of ways to sort this problem, starting with using Stage 1 like a conventional booster instead of wasting it playing elevators. But we can come on to that topic later.

The "burden of proof" I do believe is entirely on you as to why the difficulty in launching a rocket doesn't scale with the size of the vehicle...

I believe five of my earlier posts in this thread, of May 19 2004 @ 04:29, May 20 2004 @ 18:05, May 21 2004 @ 03:35, May 21 2004 @ 18:04 and May 21 2004 @ 19:56, have already addressed most of the points you bring up now, and for that reason I do not intend to duplicate my efforts now.

Instead I will try to confine myself to as few supplemental notes as possible.

On Saturn V:

“Astronautix says that each Saturn-V shot costs about $2.22Bn each, not counting development costs”

I can’t quickly find this ref. in Astronautix, but from other sources (I had reason recently to research this topic rather thoroughly) I believe this is a misleading number. My Information is that Saturn V delivered one lb to LEO for about $2,250 in 1968 money, which would be roughly $8,500 in today’s money. That’s including all development costs. So it’s about $2Bn (2004 money) per launch of a full 240,000lb payload.

However, if Saturn V were still in production, and had been developed as it was intended to be by von Braun and his team back in 1970 or so, the throw cost/lb would have fallen between 7 and 10-fold by now; the cost lb/LEO would be somewhere between $850 and $1200 and the cost per launch would be somewhere between $250M and $500M. The topic is a big one and a confusing one, because various planned future versions were differently sized, with payloads in some cases reaching over 600,000lb (300 tons!) to LEO.

On BDB:

Saturn V is not a true big dumb booster.

For one thing, it’s far too ‘high tech’!

Experience shows that launching a large rocket is extremely expensive compared to a smaller one.

Quite true with conventional design. Quite false with BDB design.

The point about BDB is that is it’s not conventional. True BDB design discards high tech, every last tiny %age performance gain design, in favor of low cost design at every turn.

I’ve already said you can go and find out what I’m going on about in detail at "LEO on the Cheap: Methods for Achieving Drastic Reductions in Space Launch Costs" by Lt. Col. John R London III (Air University Press, Maxwell Air Force Base, Alabama) (It's available from Amazon, or you can download it in pdf format from http://www.dunnspace.com/index.htm)]htt … index.htm)

SeaDragon, because of its massive size and need to be ocean-worthy, would be no different .

You are 180 degrees entirely wrong.

What you say would be true only if ships that sail on the world’s oceans are more expensive than aircraft, weight for weight. Sea Dragon is built in a shipyard, of one inch thick boilerplate steel. So:

(1) It’s built like a ship, not an aircraft.
Hence it’s cheap; dirt cheap.
(2) It’s launched from the ocean.
Hence there’s no fancy launch pad, ground crew, etc., etc. And of course this is easily doable without people fussing around the vehicle. Ballistic nuclear subs can do it from under the ocean. Sea Dragon would be sitting on the top.
(3) The bigger a vehicle like this is built, the cheaper it gets per orbited lb.
(4) The bigger it is, the lower the structure weight per orbited lb.
(5) Getting rid of turbopumps in favor of pressure feeding greatly simplifies design and construction.
(6) The cost of design is pretty much constant, whatever size
(7) The cost of navigation and other control systems is constant, independent of size.
(8) Etc., etc., etc.,…

Sea Dragon is entirely different. It’s a real, affordable way to the heavens at last. But it requires a paradigm shift to see this. Can you manage that?

Caveats:
(1) BDB is strictly cargo: no people on board.
(2) A capsule-technology vehicle is the quickest, cheapest and safest way to create a replacement man-carrier to replace Shuttle. Existing boosters are available for such a system. Therefore it should be done now on a crash basis.
(3) Spaceplanes will come one fine day, but it will take far longer and cost far more than you have been seduced into supposing, and the traffic would not bear the cost for many years yet. The technology is decades away from being ready. After the Shuttle fiasco, going for a spaceplane now would be a strategic disaster of the first order for manned space.

OK, I looked at your stepped DH-1s from ELO to GEO. Compared with the 'traditional' refueling at LEO and moving the payload to GEO in bits, there is only a marginal delta-vee improvement, of the order of one or two earth-to-LEO fueling trips at best. In fact, given the quick way I worked it, you're talking rounding error. Like I said, Newton is not mocked.

Now for your whopper:

Nope. (We already covered this.)

Because as Progress shows,even if you were right up to this point, it's going to take 36 x 2.5 or more flights, just to have all the kit you need on the ferry ship to do the transferring. That's 90 flights.

Conservatively, double all the other flights for similar reasons. You're now over 110 flights.

(And where is the pilot going to wait for the two years or more all this will take? In his itsy-bitsy cockpit on his refueling DH-1? I fancy not. Have you given any thought to his-two-year-long life-support requirements, apart from anything else? I fancy not. How about a movie called, "Mutiny on the DH-1"?)

Last time I looked, you said 30,000lbs. I don't know where you got that from, never mind 50K. I'll stick with 30K thank you because ironically 50K would be too heavy for most GEO purposes(g)

Anyway ...

110 earth to LEO trips @ $17M = $1.870B = $62,000/lb.

Congratulations! Once again you've made Shuttle look cheep!

As I feared, it is you that does not understand Newton, or the rocket equation. Staging does NOT improve the performance of a given rocket, as you and TRC seem fondly to imagine. Staging lets two (or more) rockets do more work than one rocket. But the individual rockets don't get any better, as DH-1 is supposedly going to do.

... you said. Sorry, that was tosh and remains tosh. In any case, even if it were possible to take 30,000lb payload from LEO to GEO, how do you get your 30,000 lb payload up to LEO in the first place?(g)

(DH-1 x 2) payloads is 10,000lbs. That's what you can get to GEO, and it's still not enough to get any GEO business, so by the time you're finished, you'll still need 65 or so ground launches to get a serious GEO payload up there.

As I said, this is where TRC finally parted company from reality. Newton will still not be mocked.

The Soyuz comes in a variety of weights, but the basic three-man command module (ie., the living module for a crew of up to three) masses in at about 8 tonnes. (That's almost 9 US tons, BTW)
I do not believe that DH-1 could provide a life support 'module' for three astronauts for any less mass than this.If it could be done for less mass, the Russians would have done it.

As a cross-check, the Apollo three-man Command Module weighed in at about 6 tons, from memory, but that had life support for no more than an hour or two; most of its life support came from the Service Module. Take away the CM heat shield and add life support and 8 tonnes sounds like the right ballpark.

And take a look at this:
http://www.astronautix.com/craft/apouec … ouecsm.htm
5 crew, 16,800kg.

With a DH-1 payload capacity of 5,000lbs, as I said earlier you'd be lucky to be able to keep the pilot alive, never mind passengers.

Thank you for pointing out Progress to me. You're quite right about ISS being refuelled by this. What you overlooked, however, is that it points out that by the time you install all the tankage and pumps and other controls, etc. to handle the propellant, the mass of propellant deliver is clearly going to fall from 5,000lbs per trip to LEO to something more like 2,000lbs, if that.

Thus the number of earth-to-LEO journeys has just jumped up from 65 to something more like 160 or so per GEO mission.

The payload that can be carried by Soyus varies a lot depending on which mission you look at, but it would be reasonable to say about 8,000 kg average. That's about 17,600 lbs.

At $30m/launch, that's roughly $1,700/lb to LEO, half the cost/lb of DH-1.

Soyuz can carry three people. Your people-carrying ability of DH-1 is hoplessly, laughably, over-optimistic.

Q.U.E.D.

I'm not doom-saying, I'm just realistic. You should try it some time. A lot of the problem with manned spacefight--from the very beginning--is it's been populated with people who don't like to have their dreams brought back down to reality.

For just one example, Shuttle's $60/lb to LEO promise

But apart from the fact that an opinion can be a “reason or an argument”, all I was doing here was countering your opinion that some people claim that “We don't do it that way so it can't be done.” This is a pointless discussion if you can’t comprehend that.

(BTW Where did you get this mysterious 2.2 tons from? Last time I looked your payload was 5,000lbs which is 2.5 US tons. OTOH if you want to go metric, that’s fine but please tell us.)

Not so much heavier. Maybe 7,000 or 8,000lbs. Work it out. And anyway, how do you get an 8,000lbs load up to LEO in the first place? All you can lift to LEO in DH-1 is 5,000 lbs, remember? And you’re still going to need 22 refueling missions.

And, as I said before, “To achieve this takes about 82,000lbs of propellant, all of which would have to be brought up to the GEO-bound DH-1 from Earth by other DH-1s.”

Now you’re kidding us. It would clearly be cheaper, simpler and more reliable to stick with existing ground-launched ELVs than this ridiculous vessel, neither fish nor fowl.

That would work just great once you’ve got your solar power station operational. Small snag: Most SPS’s are supposed to be out at or beyond GEO. How many hundred thousand DH-1 launches (all without the benefit of an H2/O2 splitter) to get the SPS up and running, do you suppose?

Or maybe you’re planning an orbiting nuclear power station? Apart from all the tree-huggers  screaming at you, how do you propose to get the reactor up there, because as sure as God makes little green apple, it ain’t gonna be by DH-1. And I think even I might object to an operational nuclear power station in LEO.

To the best of my knowledge, you’re wrong.

Yes, this was where The Rocket Company parted company with me. The rules of orbital mechanics are the rules, yet somehow TRC seems to imagine they don’t apply if you join two DH-1s together. A.C. Clarke once wrote a short story called “The Cold Equations”. You should fetch it out and read it. In real life, it’s ‘half the number of launches for 50% LESS payload’. Oh, and that’s not just an opinion. Sorry about that, but Newton will not be mocked.

It’s earlier in this thread—possibly the ‘first’ one before it ‘broke’.

No, it’s more expensive than any current manned space vehicle except Shuttle. And as we know, Shuttle is hardly a paragon of cheapness. And DH-1’s tiny payload capability makes it pretty much useless, what’s more. It’s kinda like going back to Mercury. Yes, that’s it, it’s the first retro spacecraft.

Beside the point. The WHOLE commercial argument for DH-1 is that is cheap. But, as I have shown, it is not. Having a crew just makes it more expensive.

Also, if we have learned one lesson from Shuttle surely it is that is criminally stupid and pointless to have people on board when they don’t actually have to be there. TRC does not seem to have learned this, however.

Huh?

No, I mean running either a profitable business like airlines are sometimes(g) or useful (depending on your POV) military purposes like jet fighters, etc.

I can’t see anyone buying DH-1 and hoping to make a profit. At least, not if they’ve done their sums right. And as for military uses, if it has any significant ones, TRC won’t be allowed to sell it. As already set out here, it’s well nigh useless for GEO satellites, and beyond GEO it’s just a joke, really. Sorry, but there you are.

…and before the truck was invented they made do with mule trains, each mule carrying what? 150lbs? 200lbs? What has this got to do with the price of fish?

You’ve got this back to front. “We don’t do it that way BECAUSE it can’t be done” would be a more accurate summary of my view of your project.

Delta-V from LEO to GEO is approx. 4km/sec. If you want to return your DH-1 to LEO after depositing a satellite at GEO, you’re going to need twice that delta-V if it’s all done by rocket burns. That’s approx. 8km/sec (all of the 8km/sec you so proudly announce here) which is about the same as was required to get DH-1 from Stage One burnout and separation to LEO in the first place. To achieve this takes about 82,000lbs of propellant, all of which would have to be brought up to the GEO-bound DH-1 from Earth by other DH-1s. Allowing for spillage, etc., that means another 20 or so earth-to-LEO launches. (We'll just ignore the fact that no-one has even attempted on-orbit refueling so far, and I'm certain it'll turn out to be a highly non-trivial excercise.) Add to that the certain need for an astronaut handling crew (Basically gas station attendants) which must mean another 2 or 3 earth-to-LEO trips at least and we’re at about 22 trips, let’s say. However GEO satellites don’t typically weight 5,000lbs but at least 20,000lbs. So we’re going to need at least 88 earth-to-LEO trips. Plus when you get all these four payloads to GEO you’re going to need another crew to assemble them all together (you can’t do this earlier) check out the joined up satellite and make sure it works. Another DH-1 to LEO, another 22 earth-to-LEO fuelling trips for the assembly crew, thanks. Plus, of course, four trips to deliver the components for the satellite and another for the assembly crew. (I'm ignoring the need for somewhere for the crew to wait around for a year or so while their ship is refuelled. I suspect being crammed into DH-1 might get rather tedious afer a while.) So what’s the total? A mere 115 trips!

At DH-1’s $200/lb to LEO, your 20,000lb GEO satellite would have cost a mere $2,875/lb to GEO which is not bad admittedly. However if the true cost to LEO for DH-1 is more likely to be $3,500/lb as I have shown earlier, the true cost to GEO would have been in excess of $50,000/lb.

One possible area for cost reduction is returning DH-1s to LEO or (more likely) earth by atmospheric braking. I guess this would reduce the delta-V requirement from 8km/sec to about 5km/sec, and so the refuelling missions (including gas station attendants) from earth to LEO to about 14 (from 22) so total trips to LEO are now a piddling 65 and the cost to GEO for the payload would be about $28,000/lb.

Whether it takes 115 or 65 trips to get that satellite to GEO, can you imagine any customer crazy enough to go along with a harebrained scheme like this? Do you really imagine you could fly as many missions as this without something going wrong, screwing up your whole schedule (at least)? Even without any failures, even with almost instant turnaround on the ground and remembering you have to launch so as to allow orbit matching, how long to do you imagine it would take to launch, rendezvous, dock, etc. 65 flights? A year? Two? And if you needed 115 flights?

Especially since in comparison with existing commercial GEO launchers DH-1 is far more pricy?

Get real!

Of course the same killer problems apply to any mission for DH-1 to the Moon, Mars, or indeed anywhere beyond LEO.

Not until it’s had 22 refuelling visits from the ground it can’t.

Spacecraft are not aircraft. Your Stage One pilot remains effectively useless. I don’t say putting people in space is pointless, but proposals like DH-1 just make the case for manned flight that much harder to justify.

It would be even easier to use if it just sat unmoving on the ground, and would be about as useful. Think balloon!

There are things to do with fighters and passenger planes. Not DH-1. (See above)

Thanks for pointing me at this.

The information is interesting and very useful. However, I'm not sure Mini MagOrion is likely to be a fully functional system ready for use on the scale required here any sooner than laser induced fusion, and fusion has a number of attractions, everything else being equal. For one thing it's characteristic Isp should be higher, and for another the exhaust should be a lot cleaner-- and easier to defocus, helping keep the treehuggers (relatively) quiet.

But these are relaively minor points. One way or the other, this is the way to colonise the Solar System, I'm sure. But you'll never do it with DH-1, delivering its baby-sized helpings to LEO.

To make the atomic spaceship a reality, you don't need a toy, you need the big dumb booster!