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The Heavy-Lift Fetish

I've discussed this many times before, but Al Fansome has a useful comment over at Space Politics (scroll way down--it's in the forties):

Other than Bob Zubrin (e.g., the Mars Society), I don't know of any space advocacy organizations who have made super-heavy-lift a priority. The only reason that super-heavy-lift is a priority now is because Mike Griffin came in and made a command decision. He already knew the answer -- ESAS was a facade to justify the decision he had already made.

Let me try to give you a serious response to your question.

Have you thought about how all the truly GREAT engineering projects on this planet have been built?

Let me list a few obvious ones.

- The Pyramids
- The Great Wall
- The Empire State Building
- The Hoover Dam (or pick your favorite dam)
- The Eiffel Tower
- The Kremlin
- The U.S. Capitol Building
- The Statue of Liberty
- The Golden Gate Bridge

They all have at least ONE thing in common. The pieces of each & every one of these great engineering projects were transported to the final site in pieces, and then assembled on site.

Great engineering in enabled by low-cost transportation and the ability to assemble the technology on site.

We are KILLING ourselves by not taking the same approach to space.

Next -- think about standard home construction.

1) There are estimated to be more than 100 million homes in America.

http://www.census.gov/prod/1/pop/p25-1129.pdf+Number+of+houses+in+United+States&hl=en&ct=clnk&cd=2&gl=us

Of that number, the estimated number of mobile homes is ~9 million
http://www.census.gov/Press-Release/www/releases/archives/census_2000/001543.html

In other words, well over 90%, or over 90 million, of American "homes" (whether in single family dwelling, apartments, condos, etc.) are assembled by the same method that is used to assemble the great engineering projects. This choice is obviously driven by economics (nobody mandated this result.)

SUMMARY: The large majority of Western and Eastern civilization has been built using the approach of cheaply transporting the pieces of the construction project to the site, and then final assembly at that site.

So, why are we ignoring the dominant traditional approach that is used over the entire planet?

Why are we not assuming that the right way to build our space economy, and to develop the space frontier, is to develop & use reusable launch vehicles to transport things to space at very low costs, and then assemble the pieces on-site.

Mike Griffin gave a speech a couple years ago talking about constructing the great cathedrals in Europe. Well, those cathedrals were transported to the final site in millions of pieces, and then assembled.

We continue to treat space differently than earthly endeavors for contingent reasons of history, not rationality or technology. Thus we get the cargo-cult approach of ESAS, in which NASA attempts to replicate Apollo, except without either the associated urgency, or the budget.

[Update on Sunday afternoon]

Since some people seem to imagine that the oil rig is a useful analogy, let me expand on it. It actually is one, but not in a way advantageous to the heavy-lift fetishists.

Yes, it is assembled in port and then towed to its operational location. But this is in no way analogous to assembling on the ground and launching to orbit. This is because of the huge energy barrier between the two. It's no big deal to tow something from one place in the ocean to another--that's a very old technology, and an extensive transportation infrastructure exists with which to do so. Thus, it makes sense to assemble it essentially in the ocean, but near land, to take advantage of the local work force.

But note that what we don't do with oil rigs is assemble them in Colorado, and then build a humungous custom truck (and associated reinforced roads, with clearances) to move it to the shore and put it in the water. But that's essentially what people are proposing in saying that things should be fully assembled on earth, and then launched into space, on a giant rocket that flies just once in a while, at a very high cost (particularly after amortizing the development cost).

In space the oil rig scenario would be analogous to having an existing assembly facility in LEO (that had presumably been bootstrapped up), with a robust low-cost transportation infrastructure to get things to and from earth, and from point to point in space. The "oil rig" (or large telescope facility, or prop depot for use at L1) would be assembled there, and then a space tug would move it to its final destination.

This was in fact part of the original vision for the SSF in the eighties. The "dual truss" configuration was intended to act as an orbital assembly hangar. Unfortunately, we didn't have the transportation infrastructure to support it. But the fact remains that what we need is not heavy lift, but affordable, reliable and frequent lift. Once we get the latter, it will become clear how to best utilize it to accomplish our goals.

 
 

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39 Comments

Aaron wrote:

I don't know. Heavy (er) lift makes a lot of sense to me - provided your goal is to see large scale engineering in space - the sort of equipment mass needed to sustain a human presence.

Assuming you can't do general replecation using microscopic devices via nanotechnology (and until we can build a macroscopic van-Neumann replicator, there is no reason to assume microscopic ones are around the corner) then establishing a human presence in space requires establishing not only a biological ecosystem, but an industrial one as well.

This requires the transportation of at least a few tens of thousand tons of equipment mass to the in-situ resource destination of choice.

This in turn requires a whole lot of rocket no matter how you slice it. Once you've made the decision to establish a human presence, you can vary how you divide the required rocket mass into an unfathomable amount of small launches or a much smaller (but still immense by modern standards) number of larger launches.

But whatever you do, it'll look a lot different from what you need to launch and maintain a handful of microscopic communications sattelites and space probes, or what you need to shuttle personnel back and forth.


Aaron wrote:

PS - you need a lot more than a handaxe and a rifle to produce machine tools and bio-matter from de-volatilized oxides and trace gasses.

Aaron wrote:

PPPS - Economics doesn't drive demand for such large launchers now - but that's because economics isn't driving for a human presence in space right now. That's more on the level of our "national hobby" at present.

What economics demands right now is communication and observation sattelites pointed at earth. Dissappointingly, there isn't even enough demand for privately funded space telescopes or probes.

ken anthony wrote:

1) pieces...
2) transported to the final site...
3) assembled on site.

How heavy determines how big the pieces can be.

With regard to chemical non reusable rockets...
There's an optimum size which results in the lowest transport cost. I suspect this size is greater than current or even past capabilities.

Assembly cost is lowest on earth. For now, the cost is much greater in space.

No matter how heavy your lift capability, we are likely to always want to build things that must still be assembled in space due to their size. Orbital refueling also seems like a no-brainer to me.

RLVs will prove themselves one day. That day isn't here yet. Should we wait?

Conclusion: Does anybody expect NASA to make the right choices?

I think the argument is mute. We will use whatever capability we have and should design for what we have now or is near readiness. Bigger rockets are going happen incrementally in any case.

We should be concentrating on spacecraft and missions.
Industry will provide the rockets. NASA just hasn't realized yet that it's not in the rocket business anymore. Come to think of it, they shouldn't be in the spacecraft business either. Just come up with missions.

Carl Pham wrote:

Well...the problem with arguing by analogy is it can very easily be done the other way, like so:

Do we assemble submarines by sinking hull plates and piping and electronics et cetera, then assembling it all underwater and pumping the water out? Nope, we build it on dry land, then move it to its operating environment.

When we build an offshore oil platform, do we transport all the parts to the drilling site and assemble it in place? Nope, they're built on dry land and towed to their final location.

That is, here on Earth when the final operating environment is an unusually difficult place to build something, we do our best to build it where it's easier to do so, and transport it, even if that involves fairly massive transport logistics.

I'm not saying this is a correct argument, but it's no less correct than the argument made in the post. I think a convincing argument for the appropriate size of the next lift vehicle has to be made with direct reference to the conditions of orbital transport and assembly.

ken anthony wrote:

Carl, you rock.

Mike Borgelt wrote:

Robert Heinlein once invited us to think what an automobile would cost if raw materials were delivered to your homeand a few guys turned up to assemble it in your driveway.

I don't think the pyramids thing is a good analogy.

Build anything in a factory in the largest chunks you can reasonably transport. Look at how Boeing and Airbus build airliners.

Carl is right.

Doug Jones wrote:

Carl, the crucial difference in your analogies is the break between waterborne and other transportation. Large systems at sea can be built in a dock, then floated away. For *any* other means of transportation, build-on-site wins. Even bases at the south pole, arguably the most extreme non-marine environment on earth, are built on site with only limited use of modules larger than a shipping container.

LEO is more like a dry land site than the ocean, in that the assembly process can go on without worries about winds and waves tearing the construction project apart before it is complete.

An RLV with 1000 kg payload can help in outfitting a space station, but it is true that major components such as pressure hulls would preferably be launched on larger vehicles. On the gripping hand, this does not argue for heavy lifters lofting 100 ton lumps.

My humble opinion is that a limited number of EELV-class launches could lift the core of a propellant depot and assembly station, then additional components and all the propellants could go up on smaller RLVs.

Earthly airborne heavy-lift vehicles in the form of airships have been proposed and built many times, but never found a useful economic niche. I suspect that heavy-lift launchers are much like the Hindenburg, national prestige projects that operate at a loss.

Robert Horning wrote:

The assumption here that is made but not written about is the following:

At what point do you have a space launch system that the engineering and development costs are insignificant compared to operational costs and the raw materials of building/fueling the spacecraft?

Obviously building a launch system that will ultimately have only a few flights is not going to be in this sort of situation. Another huge issue is that a launch system that requires 10's of thousands of workers on the ground just to get the rocket up (aka the Space Shuttle) is going to be substantially more expensive than a vehicle like a 747 that has only a couple dozen crew members.

Before you start to think I'm comparing apples to oranges here with a Shuttle vs. 747, keep in mind that the amount of energy used for thrust to get a 1st class passenger from Los Angeles to Sydney is nearly identical as the Space Shuttle requires in order to get to low-earth orbit (per passenger). Both require professional operators flying the vehicles, but it is a heck of a lot cheaper to fly the 747 to Sydney. About the only major difference is that a 747 doesn't have to carry an oxidizer with the fuel on the trip. It would be interesting to speculate what the operational parameters of a 747 would be if the oxidizer was carried in separate tanks, including subsequent reductions in cargo/passengers. Such an aircraft wouldn't be completely impossible.

Heavy lift rockets like the Ares V simply will never have enough flights (barring something weird like NASA getting to mid-1960's level of federal budget compared to other programs) to justify the expense of making the rocket in the first place... other than as a pure prototype to push the boundary of rocket technology. Certainly not enough to justify its use as a transportation system.

In other words, flying 100-10 ton rockets would be considerably cheaper than 10-100 ton rockets just due to improvements in economies of scale and the ability to set up a fabrication line that can apply principles of mass production. Rocket fuel costs at the moment are so insignificant as to be simply fiscal noise, where more is spent by NASA on janitorial services than they spend on fuel for the Shuttle program.

Tom Hill wrote:

Similar to previous commenters, I say split what can be split (propellants, internal components, food, water, etc) and keep living spaces and major components whole. The exact balance of this will need to be worked, and doesn't drive the need for an ultra-heavy lifter, but would definitely cause a shift in today's approach.

Another note on the submarine analogy: Aircraft are built in a factory and then shipped. Wings, fuselages, engines, etc are not delivered to the end of a runway, assembled, and flown. The antarctica analog is pretty good, but you can build insulated, unpressurized living spaces much easier than you can build an integrated craft required for space. Anything technical (generators, etc) arrive at the South Pole in one piece.

A note on Bob Zubrin's heavy-lift thing: His original proposal saw Mars missions taking place while the shuttle was flying. It made maximum use of shuttle components, including off-axis mounted SSMEs that could use the launch pads. He hasn't updated the approach much since then.

DocBrown wrote:

Robert Horning Said

"About the only major difference is that a 747 doesn't have to carry an oxidizer with the fuel on the trip. It would be interesting to speculate what the operational parameters of a 747 would be if the oxidizer was carried in separate tanks, including subsequent reductions in cargo/passengers. Such an aircraft wouldn't be completely impossible."

A 747 weighs 393,263 lbs empty.
LA to Sidney: 12,065 km (great circle distance)
747 Max Range: 13,450 km

Fully tanked for a long haul (with reserve), it contains 395,523 lbs of Jet A. Max takeoff weight is 875,000 lbs leaving 86,214 lbs for passengers, cargo and oxidizer. With a full complement of 416 passengers at an FAA average winter passenger weight of 189 lbs this leaves only 7,590 lbs for fuel and oxidizer, let alone luggage.

So how much oxidizer do you need to burn this 395,523 lbs of Jet A?

The greenhouse gas industry informs us that burning a gallon of Jet fuel (6.7 lbs) produces 21.1 lbs of carbon dioxide, so you need 14.4 lbs of oxygen for every gallon of Jet fuel to burn the carbon.

But Jet fuel is a hydrocarbon, containing hydrogen and carbon. So we need more oxygen to burn the hydrogen (which will turn into H2O).

Jet A is similar to kerosene and contains approximately 26 Hydrogen atoms for every 12 Carbon atoms. Each carbon atom bonds with 2 oxygen, and each 2 hydrogen atoms bond with one oxygen, so hydrogen requires 1/4 as much oxygen. Therefore the oxygen required for burning hydrogen is 14.4lbs x 26/12 x 1/4 = 7.8 lbs. (I hope I haven't made a mistake here).

So for each 6.7 lbs (gallon) of Jet A, you need to carry an additional 14.4+7.8 = 22.2 lbs of oxygen.

So if we allocate the 395,523 lbs of fuel capacity to fuel units of 22.2lbs oxygen + 6.7 lbs Jet A = 28.9 lbs, we get 13,685 units, including 13,685 gallons of Jet A, compared to our previous capacity of over 59,000 gallons, or a reduction of almost 77%.

So let's eliminate all of the passengers and cargo and allocate the full fuel, passenger and cargo weight to fuel+oxidizer.

Thats 395,523 for fuel plus the cargo and passenger allocation of 86,214 gives 481,737 or 16,669 gallons of Jet A plus necessary oxidizer, totalling a reduction of about 72%.

I doubt if you would make it to Seattle, let alone Sidney. Plus you would have no reason to go.

ken anthony wrote:

What is the difference between a 100 ton rocket and a 10 ton rocket?

1) Smaller is less capable.

TRUE. 100ton can lift 10ton, but 10ton can not lift more than 10ton. There's no room to argue here. You have more flexibility in payload design with the larger payload.

2) It's cheaper to build 10 - 10ton than 1 - 100ton because of economy of scale.

I would say this is not true. Just because NASA doesn't work like a private company, doesn't mean a private company can't. 10 times production is not that great a scale to make that much difference. Most of your economy of scale comes from working out the production bugs in your first few products. The other saving is in bulk purchase of material, but in this case it's not going to be so great a difference.

3) Larger rocket requires larger ground crew.

Really? Why? Assuming a larger rocket is 3 stage instead of two, it requires more sensors and may take a bit longer to prepare for launch, but that does not mean it takes a larger crew.

4) Currently, the small rockets exist the bigger don't.

So designing a payload for a non existent rocket means your critical path is external; never a good idea.

Conclusion: In my mind, we should be designing for the rockets we have and let industry work on larger because they will (because point 1 should be obvious to everyone.)

The fact that NASA has decided to build a heavy lift vehicle has no impact on the argument above.

ken anthony wrote:

If you disagree with me regarding the savings in bulk purchase of materials. Please keep in mind that 10 - 10 ton rockets will use more material than 1 - 100 ton rocket which likely overcome any difference in bulk material cost.

Not only that, as a businessman, if I can't negotiate a good price for a single rocket (which uses a significant amount of material all by itself) buying more material isn't going to make that much of a difference.

Say I negotiate 10 to 20 percent off. Buying more might give me 15 to 25 percent off. Of course, I'd start with 30 percent off, but that's just me ;-) In any case, your smaller rockets are going to eat up that difference because they require a greater percentage of material for the same lift mass.

ken anthony wrote:

LEO is more like a dry land site than the ocean

Except that working in pressure suits and needing to brace yourself so the wrench doesn't turn you might overcome the nice weather.

Perhaps a large enough spacedock could mitigate that, but we are a long way from there.

Robert Horning wrote:

I don't get it in terms of why economies of scale aren't cheaper building 10 rockets vs. 1 single prototype.

Just as SpaceX is abundantly proving, getting a rocket built requires an incredible attention to even the smallest details, and it requires several flights to work things out... for even the best of the launchers. I could name examples of launch failures by ESA, NASA, and RSA that have all been spectacular, including some manned flights (unfortunately). I would dare say that in some ways NASA is finally getting the bugs worked out of the Shuttle system just in time to get it retired.

All of these early prototype flights, engine tests, and other similar development costs all are incredibly expensive, and you really don't get any launch system to pay for itself until well after it has been launched a couple of dozen time. *THAT* is the economy of scale that I was pointing out.

In other words, the Saturn V had only emerged from its prototype status after the completion of the Apollo 17 flight. Certainly the Ares V (VI?) will only have at best a dozen or so flights in its projected lifetime as well. I would love to seem any documentation at all that suggests a much higher launch rate for these big launch vehicles.

Yes, I can think of some vehicles that are built and developed as a singular example of that kind of vehicle and no other copies of that vehicle are ever built. Most of them are trans-oceanic ships, and even then there is a huge economy of scale in terms of producing multiple copies of the ship in a production line. Look no further than the U.S. Navy for good examples of this. Furthermore, ship-building has one huge advantage: having the vehicle travel from New York to Liverpool is not going to be the only trip that vehicle will ever make. Systems can and routinely are heavily modified during "sea trials" during the construction phase of those kind of vehicles.

So I still contend that it is by far and away cheaper to break up a 100 ton payload into 10 ton chunks and fly them into space in pieces. The reason I use the figure of 10-tons is that can be a good value for a payload that has some usefulness, and can also support manned spaceflight with life support equipment and re-entry gear.

Larger rockets, when evaluated individually and once they have been completely developed, are in fact cheaper to launch than smaller ones. But the problem here is where do you draw a reasonable line for something that is going to have a high enough flight rate to justify its cost to develop in the first place. I contend that the development costs of larger vehicles scales worse for its size, even if ultimately they are cheaper to operate on a per ton of delivered payload basis once those development costs have been covered.

That is why it isn't a simple 1:10 ratio that has to be considered erroneous and that a 10:100 ratio, while mathematically identical, takes into account these R&D costs a little bit better.

john hare wrote:

All the above arguements are valid and rational in both directions. The problem is that no rational designer of any structure on Earth starts by specifying a new transportation system. If you want to get something built, don't spend most of your budget reinventing the square wheel.

Even if they are gouging, (and they will) it would still be cheaper to pay for delivered components than to start all over. Offer $100M per astronaut delivered to ISS and returned over the next 15 years and you will get crew transport for less than the stick.

Offer $30K per kg of assembled, functional space structure that does X, and it will still be cheaper than the current plan.

Just pay somebody for results, and don't pay for promises. If a half century into the space age, we can't get the job done for a reasonable price and schedule, maybe we should wait until we can buy transport from Ethiopia or Iceland.

anon wrote:

On-orbit assembly will typically increase ops costs. Especially with the current NASA policies and practices. Current NASA flight crew and flight controller training and ops costs are driven by the following factors, in order of priority: Astronaut safety; train the astronauts and adjust ops and hardware as-needed to make the odds of a significant astronaut error approximately zero; train the flight controllers and adjust ops and hardware as-needed to reduce the odds of a flight controller error resulting in serious consequences to approximately zero; be ready for Apollo XIII, Part II: identify every 'credible' hardware or ops error that could occur in-flight and train the astronauts and flight controllers to deal with them (and develop special tools as-needed, especially EVA contingency ops tools). All of that is good, but does NASA take some or all of those areas too far to justify the costs versus the potential risks, and would non-NASA outfits do it the same?

ken anthony wrote:

Robert, you're talking about amortization of development costs. That's a different thing than economy of scale which is most effected by material and transportation costs.

Development costs are incurred up from mostly. Fewer flights does mean the allocation per flight is higher. One thing SpaceX (assuming they do succeed which I do) has shown is you don't need to blow billions to make a rocket.

Eventually, I believe they will also show that operating cost will be much lower as well. Finally, I expect the F9 heavy is not the end of the road and they will show the same reduction in costs (development, operational, etc.) for much bigger rockets when the market supports that.

ken anthony wrote:

up front, I meant. One day my fingers will connect with my brain.

Carl Pham wrote:

Thanks for the update in the original post, Rand. In case it's not clear, my comment was meant to point out the flaws in the argument by analogy, not make an argument one way or the other on heavy-lift.

To the extent I have an opinion on heavy-lift, I would venture to say it seems a little odd to imagine only one lift weight. After all, we have trucks in all sizes from very light-duty 1/4 ton pickups, with which one can deliver only a few bicycles, to enormous 60-ton triple tractor-trailer combinations. Each has its place. One would think that a fully mature orbital delivery system would have a variety of vehicles, from light- to heavy-lift.

Al Fansome wrote:

Interesting discussion here.

1) I agree with the Doug Jones' statement that a limited number of EELVs for large components, plus RLVs for things that can be broken down into smaller pieces.

2) Robert Horning argues the point that 100 10-ton ELVs is cheaper than 10 100-ton ELVs.

This argument can go either way -- in any case neither side can demonstrate more than a relatively small advantage over the other. For this reason, I suggest that Mr. Horning's comparison does not go far enough.

If you have a market larger enough for 100 10-ton ELV flights, then it is basically large enough to justify investing in an RLV.

The comparison then becomes ...

What costs more?

10 Ares V-class expendable LVs that can launch 100 tons per launch.

***OR***

One (1) RLV that launches 10 tons per launch and can repeatedly launch 100 times on short turn-around (say a week) before end of life?


3) On the Submarine/Oil rig/Car manufacturing analogy -- the appropriate comparison here is building a large structure in LEO, and then transporting it somewhere else in the solar system (GEO, Moon, Mars, Lagrange points, asteroids, etc.) using much-higher ISP systems.

On the issue that NASA can't do on-orbit assembly in a low cost manner --> I never suggested that NASA should be tasked with this responsibility.

NASA should get out of LEO .... and hand LEO off to private industry.

When we finally have RLVs, private industry will quickly (learn and) demonstrate how to do on-orbit assembly MUCH MUCH cheaper than NASA. In fact, industry only needs to look to the Russians for an example on how to assemble things on-orbit a lot cheaper.

FWIW,

- Al


Michael wrote:

Rand,
I think this is something of a false dilemma. When the kind of developments that you are talking about, and people like Space-X are actually working on, high reliability low maintenance rockets that can reduce the overhead cost per lauch by orders of magnitude and exploit economies of scale through frequent launches are actually produced, they will be just as applicable to all sizes of launch vehicle. Consider ocean going ships as an analogy. They have all of the characteristics that you want to see implemented in launch vehicles and they range in size from small craft that carry only a few people or a few hundred pounds of cargo to gigantic super tankers that can't even enter most ports. Each are used, economically, for the purposes for which they were constructed. Once we have spacecraft that have similarly economic usability, the debate between small and heavy lift capability will simply vanish. Undoubtedly there will be small rockets capable of putting just a few hundred pounds in orbit and large ones which will make the Space Shuttle or the Saturn V look small in comparison.

Rand Simberg wrote:

Neither I or (I think) Al is arguing that there will never be a role for heavy lift vehicles. But until there is sufficient demand for them to be operated cost effectively, they will make no economic sense. If we want to get into space affordably, we'll do so initially with high-flight-rate smaller vehicles, not low-flight-rate large ones. The first successful airliner was the DC-3, not the 747. There are good reasons for that, and they apply to space as well.

Rod K wrote:

The Berlin Airlift is another analogy. Not in building items at the destination but in the amount of stuff that can be shipped. And remember most of the mass that one needs in orbit is PROPELLANT. One can easily envsion an Apollo class Moon trip using a Delta IV as long as there is a supply depot in LEO.

http://en.wikipedia.org/wiki/Berlin_airlift#Berlin_Airlift

Al Fansome wrote:

RAND said: Neither I or (I think) Al is arguing that there will never be a role for heavy lift vehicles. .... The first successful airliner was the DC-3, not the 747. There are good reasons for that, and they apply to space as well.

I agree 100%.

- Al


kert wrote:

The biggest mistake of space history was ditching the Gemini lunar approach and building the Saturn V. We would not be having this argument here and some of us would probably sipping margaritas at Tranquility base lunar resort.

Andrew wrote:

OK, if it is better to build using small pieces, why are the pyramids build out of blocks of ton a piece. Using the above logic, wouldn't it have been better to build using smaller units, like bricks used to make houses today.

Isn't it all down to energy and the current level of technology. Look at what is happening in the shipping industry. Ships are getting larger. Trucks are not getting larger due to limits, not of truck tech (think mining trucks) , but the infrastructure e.g. width of the road and clearance under bridges, etc.

Imagine if the ISS was built out of 10m dia 100 ton modules launched on top of shuttle 'c' launcher instead of needing to fit in the shuttle. For the same volume, fewer launches.

Size has a certain logic, but in the end it comes down to energy/cost. For the pyramid, it was more hassle to cut smaller blocks instead of moving the larger blocks.

Andy

Robert Horning wrote:

The extended Gemini (aka "Big Gemini") was not something developed by NASA except as a thought on how to extend the technology of the Gemini vehicles to something a bit more relevant. For some details about this, see:

http://en.wikipedia.org/wiki/Big_Gemini

In truth, these spacecraft designs show more similarity to the Soyuz capsules than even Apollo. It should also be pointed out that the Saturn V and the Apollo spacecraft had their designs started well before the Gemini designs were even given a green light to get started in the first place. If anything, Gemini represented the next generation of spacecraft _after_ Apollo. Thus, there never really was a serious consideration about extending Gemini technology for lunar missions.

What is unfortunate is that NASA threw away not just one but two different spacecraft designs (Apollo, after making it through the Lunar exploration program and Gemini) in favor of a spacecraft that simply couldn't do the missions that the other spacecraft did (the Shuttle).

Unfortunately, the Congress in the 1970's wasn't in the mood to support more than one manned spaceflight program, and didn't realize what it was that they were throwing away... just to have some engineers try to revive those programs 40 years later at great expense.

I also think NASA is doomed to repeat history here again and again unless they make some major changes to their organizational structure... or perhaps that is simply government involvement in general.

----

In regards to the pyramid blocks and their sizes, there is a certain granularity that would be useful for construction in space. I'm not sure what the best size would be for components, and in fact it likely isn't the 10 ton size that would work. The Space Shuttle has a payload capacity of about 20 tons, to give a reference point here. It should be noted that there are several modules that have been built that could be attached to the ISS, but haven't been sent up simply due to budget cuts and delays due to the loss of the Columbia.

Certainly the Shuttle never achieved its promised flight rate of about 2 flights per month, which was one of the original goals NASA claimed back in the late '70's and early '80's in congressional testimony. Had the Shuttle been able to live up to that promise due to better engineering/design/making this a primary goal of the program, the picture for U.S. spaceflight would be quite a bit different.... and justify the 100+ astronaut corp that NASA currently has.

Daveon wrote:

What we do do with Oil Rigs is assemble them in Scotland or Norway or similar and then often tow them really vast distances with heavy tugs until they're in position. What they don't do is try to assemble them from small units in the middle of a hostile sea environment.

Take a look at the the history of the Sea Launch Rig and how far that thing has been towed around the world. It may have started life in the Pacific but it's traveled a lot further than that.

Daveon wrote:

Pressed send too soon:

While I know you made the point that towing rigs is using ancient technology, you're not quite right.

As BP and other companies are keen to tell you if you spend time in the ship building industry (where I started my career) the leap in technology deployed to move to North Sea Oil Operations was comparable to that needed to put people on the moon. Nobody had ever tried to extract oil from that depth of sea, nor in those conditions before. From rig design, through operations (diving in particular), they created a whole bunch of novel technologies and solutions - they weren't even entirely sure that you could tow and position rigs correctly.

This demonstrates two things, that we often underestimate just how hard a lot of things are and secondly that a lot of earth based analogies to space related endeavours don't work very well.

Even now, if a rig needs a major repair or work, it's frequently towed out of position and worked on in Dry Dock in Norway and Scotland rather than try and do anything in the North Sea.

Habitat Hermit wrote:

A bit off-topic but I'll add this on road trains:
"In 2006, a truck with 112 semi-trailers (at a length of 1,474.3 m (4,837 ft)) claimed a new record at Clifton, Queensland."

From Wikipedia.

Now is that an argument for heavy lift or for modularity? ^_^

Kelly Starks wrote:


Intersting how the HLV vrs LLV and lift lots of small peaces argument get so contentious. Youíld really need to trade study what you are lifting. On the ISS we did do assembly in peaces, but because the peaces were brought up scattered over years, it ment the platform had to be designed to be functional at each step of the assembly. Rethink the Submarine/Oil rig/home/Car manufacturing analogies assuming it has to be functional art each step. Also astronauts in the field have little dexterity, and virtually no tools to test the integration quality, etc. So its not like assembling things in a harbor or factory, but really is like assembling a submarine underwater from parts dropped off by a passing submarine.. And some parts donít dismantle well (Big engines, pressure vessels, etc.).

Actually there is probably a better argument for over sized cargo, then heavy weight, given most all of the weight is fuel and consumables that can be brought up in lots of little globs Ė of course the oversized vrs compact concept would just start another religious war.

;)


Oh I liked Andrews
>> OK, if it is better to build using small pieces, why are the pyramids build out of blocks of ton a piece. Using the above logic, wouldn't it have been better to build using smaller units, like bricks used to make houses today.
Counter analogy.

Hell the only reason we donít build homes in major subassemblies (if not complete) and ship them to the site for installation, is transportation and zoning limitations (the later more to preserve local carpenter jobs then anything else.).

I really think, given to start we really arenít going to get a fleets of different sized ships and small ships arenít proportionately cheaper then big ones, we build a pretty good sized ship. 18,wheeler to shuttle sized. Ability to lift outsized cargo externally would be a big plus. That should cover about anything from passengers and smallish sats, to space station and lunar base construction programs; and to get any economies of scale you need something that can serve most any current market. A 18 wheeler to space..

Fletcher Christian wrote:

Daveon: In my humble opinion you are using a false analogy. Take the bits of an oil rig out to sea and attempt to assemble it on site, and you will lose them. The sea is an extremely hostile environment, or can be at completely unpredictable intervals, and one more thing; unless you take measures to ensure that they do, things don't stay where they are put. Try letting go of a chunk of I-beam while you are holding it over the side of a boat, sometime, and you'll see what I mean. Or rather don't bother, because it is obvious what the results will be.

On the other hand, leave something in space (OK, minimal tethering would be needed in practice) and it will stay where it's put. What's the reason for the difference? Something so pervasive and so obvious that we forget about it - GRAVITY.

In addition, several people here have said that space is hostile. This statement is not original with me; but it's a darn sight less hostile than a lot of places humans have been. Sure, space doesn't give you anything - not even air to breathe - but in fact it's a pretty benign environment, especially if equipment is appropriately designed.

To illustrate this; one of the Apollo missions included a side trip to pick up some bits of one of the old Surveyor probes, after a 10-year wait. It was in pretty good shape. Now imagine what shape the same piece of equipment would have been in, if it had instead been dropped on to the bottom of the Gulf of Mexico.

Space won't forgive any mistakes; but unlike many other places people have been, it isn't actively trying to kill you.

Daveon wrote:

Fletcher: I think you misread me. That was the point I was making. That's the reason why we had to develop a lot of very, very cool technologies in the first place to build deep sea oil rigs.

I'll stick with the Space is Hostile camp though. Before we discuss that in more detail: Define what you mean by "pretty good shape".

kert wrote:

Robert, i wasnt talking Big Gemini, i was talking the 1961-'65 Lunar gemini on small booster ideas that were competing with Apollo, and got to its furthest development with Gemini-Agena tests ( docking pieces together in orbit .. gasp, what a concept ! )
http://www.astronautix.com/articles/bygemoon.htm

Tim Fowler wrote:


The Pyramids where constructed at the site, but the building blocks where large enough that moving them could reasonably be considered "heavy lift". To a lesser extent this also applies to a number of other items on the list.

Yes the pyramids heavy components didn't have to be moved a huge distance, but thats because they existed relatively near by. If we had a bunch of material which we could use to construct things in orbit than I'd agree with your point about heavy lift not being needed, but we don't.

You also use the example of oil rigs. Sure they assemble on site, but they move in really large components to do it. Have you ever seen the size of some of the assemblies they move in on "ice road truckers".

"Jody and Brett take on the challenge of removing the 66-ton derrick from the Langley site. The massive rig will have to be "two-trucked"--one truck will make the entire journey traveling backwards."

http://www.history.com/minisite.do?content_type=Minisite_Episodes&content_type_id=54708&display_order=2&sub_display_order=3&mini_id=54692

"Alex transports a desperately-needed piece of equipment to the mine; a 44,000-pound (20,000 kg) diamond-ore crusher."

"Jay takes a 95,000-pound (43,000 kg) diamond ore scrubber to the De Beers mine"

"Even though the derrick has been successfully moved from Aput to Langley, the crews cannot erect it until its 80-ton substructure is put in place. This equipment is split into two 40-ton loads and assigned to Alex and Bear."

"Heavy lift" or even "super heavy lift" doesn't amount to opposing construction in orbit. No one is proposing that large space stations be build on earth as one piece and then boosted in to orbit. Heavy lift is just a good way (or at least a less bad way then small rockets) to get a large amount of material in to space.

http://en.wikipedia.org/wiki/Ice_Road_Truckers

Nitori wrote:

Well is the HLLV better what really matters is the tonnage that can be moved overa given times vs the tonnage moved at any given moment.
I say lets compare four vehicles Ares V,Jupiter 232 aka DirectLauncher,F9-H, and shuttle II.
If Ares V can fly lets say twice a year this means 280 tons is moved into LEO.
But if Shuttle II or F9-H can fly 12 times a year and lift 25 to 30 times at a time they can lift 300 to 360tons into LEO vs Ares V's 280tons the RLV wins this battle.

The two vehicles combined could lift an impressive 600 to 740 tons of materials into LEO a year if they only manage to fly monthly.

The shuttle once flew nine times in one year so the goal of 12 flights a year for a next gen vehicle is perfectly reasonable and obtainable.
Now add the EELVs which can fly 5x each a year in their heavy configurations to that mass and the argument for Ares V becomes moot.

Now lets compare direct launcher's J-232 which lifts 110 tons at a time and likely could fly 4x a year this equals 440 tons per year it beats the either one of the two RLVs if they can only fly monthly.

Heavy lift can be a better or worse solution just like an RLV since in the end it all depends on flight rates. Ares V cannot fly often so it's a poor solution and funding a next generation RLV would be a better solution while Direct could be a good and fast solution to the cargo problem.

Fletcher Christian wrote:

Daveon, as far as I remember "pretty good shape" meant lightly pitted, no corrosion. Parts made of materials like plastic were in poor shape. On ethe other hand, remember that Surveyor was designed and built in the mid-60s, and had a design life much less than that 10 years. We could do better now, I'm sure.

As for "Space is Hostile"; well, a lot of what makes it so can be stopped with a sunshade. It is, in my admittedly unqualified view, a hell of a lot less hostile than is the North Sea in a force 10.

One thing that would be needed, and isn't often discussed, is a few observatories pointed at the Sun, and some sort of short-duration radiation shelter for when the Sun lets rip in our direction. Until a decent-sized colony with a couple of metres of dirt inside gets built; then we can stop worrying about that too, except for those actually working outside. Incidentally, the rad shelter could double as a water tank; just about all of Solar radiation is protons. The Moonbase residents would be rad shielded from the start; all you really need to arrange that is a shovel.

It might also be mentioned that a Mars surface colony would be just about as exposed to heavy-ion cosmic rays as anywhere in free space; Mars doesn't have a magnetic field to speak of, and we can't do anything about that - yet.

Nitori wrote:

One very amusing thing is the STS could have potentially move 270 tons a of mass into LEO over the course of a year which is nearly equal to Ares V.
I'm not counting Ares I since it's job can be done with an existing EELV such as Delta IV-H or the Atlas V 552.
Yes the 552's payload is smaller on paper then Ares I but it's injection orbit is much higher so the real payloads of the vehicles are actually very close.
So if NASA axed Ares and just ordered the OV200 series from Boeing which just might be able to realize the original proposed flight rate of 12x a year they could move a lot more payload per year.
The real numbers would actually be much higher since the shuttle can service a reusable solar electric or nuclear electric ion tug that could take cargo from LEO to the moon very economically.
Ion propulsion would only require 5,000 to 10,000kg of xenon gas vs 100,000kg of chemical propellants to move a 60ton mass from LEO to the moon and that number is if the tug is reused.

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