How to Make a Practical Rocket (N1 Edition)

(it was officially under consideration and intense evaluation as late as the end of '71, then was dropped from consideration--probably a contributing factor in holding onto the S-IC tooling into the summer of '72 then binning it).

Those are some interesting chapters. They put a different perspective on the politics going on around the shuttle program than what I've read previously.

Chapter 8 actually makes me wonder if the Americans wouldn't abandon the shuttle (for the 70s at least) in order to focus on competing with the Soviets with either Apollo-based hardware or a Titan IIIL+big Gemini+space station+OMB shuttle approach.

That is a good deal less interesting than the Saturn-shuttle, mind.

Looking at the Saturn-shuttle design sketches, I can't help but feel that development would present its own challenges and cost-overruns. Given that OTL's shuttle was at first intended to evolve past the TOAS approach, I have to wonder what "temporary" compromises would have been made with a Saturn-shuttle that the US would be stuck with for a generation to come...

I sort of suspect if Apollo hadn't been prevented from purchasing additional Saturn Vs in 1969 and NASA had stayed about 2% of the budget, you'd have seen something like this turn up on Apollo 20 and on. That takes some doing, but even a smaller series of AES-type missions could perhaps have been sustained every year or two in the 70s.

I suspect 1.5% of GDP is the upper limit of what is possible in the 70s.

Going from memory, I think NASA with a 3.4 billion USD budget could just about afford to keep the Saturn V in production, keep up AES-type missions to the moon and fund development of a minimal shuttle (glider type, probably with a Titan IIIL as launcher) but... I forget where I read the estimates of the cost of re-starting Saturn V production and the estimates for how much each Saturn V cost...

I have my doubts that NASA would go that way though, since it is basically pulling them in two mutually excluding directions (hence would be seen as inefficient). And from what I can remember of what moon shots cost, I'm not convinced that NASA could afford to do both a Saturn-shuttle AND an AES-type Lunar missions.

Quite. I tried to incorporate something like it into Dawn, but it ended up trying to take over and divert the timeline, so I'm planning on trying to write another short timeline on the topic. :)

I'm glad you decided against mixing the ideas. I think TLs are better with a certain degree of focus.

Though I am now thinking about what I could do with a Saturn-shuttle in a Yangel-ascendent TL...

fasquardon
 
Looking at the Saturn-shuttle design sketches, I can't help but feel that development would present its own challenges and cost-overruns. Given that OTL's shuttle was at first intended to evolve past the TOAS approach, I have to wonder what "temporary" compromises would have been made with a Saturn-shuttle that the US would be stuck with for a generation to come...

I realized well after writing this that I'd immediately started thinking of the "saturn-shuttle" as being the one with a winged first stage... Of course, it doesn't have to be winged, the basic throw-away 1st stage would not in fact present so many development risks (if any).

One of the other things I've thought about is that the external tank on the saturn-shuttle is much smaller than the one on the TOAS designs.

So not only does the saturn-shuttle have no o-rings, but it also has less to fear from foam strikes (or so I imagine) due to less tank surface area and less tank height above the orbiter.

The shuttle avoiding both of the calamities of OTL has huge implications for American space travel!

fasquardon
 

Archibald

Banned
New film showing N-1 7L in flight
https://www.youtube.com/watch?v=OZdcaub1BfU

And, even better - according to a space historian

According to a knowledgeable source I conferred with, this footage is not new. It has been around for quite awhile. I have heard, however, that there is a bunch of N-1 footage that is quite good but has never become public. A colleague of mine was shown some of it years ago by a retired Soviet general. Hopefully someday we'll get to see that footage.
 
Hmm. There seems to be much less turbulence in the N-1 launch than in the Saturn V launch.

fasquardon

That 'turbulence' I think is because the Saturn V Launch was shown at a later phase in its 1st Stage Burn, and part of the atmospheric interaction as its velocity climbed.

The N-1 Launch seems to have been shown at an earlier phase, definitely before the 100-second mark.
 
I have often wondered what aerodynamic penalty, if any, the N series designs would have to pay for that sloping breadth of the lower stages due to the stacked sphere design.

Note that the slope is not so much just because the fuel sphere is above the larger oxygen sphere, but rather because the upper stage must nest atop the lower and must be smaller, so its oxygen sphere must have a lower radius. We could easily get away from two spheres per stage by putting the fuel in non-spherical tankage--I envision in the awkwardly shaped space below the oxygen sphere. But this would actually worsen the slope of a smooth conical line enclosing the second stage, if it too had an oxygen sphere "floating" on top of a cup of kerosene tankage! By bringing the centers of the two oxidant spheres closer together, the difference in radii reflecting the cube root of the differences in gross mass would be accented; given that one chooses to hold the cryogenic and dense oxygen in a sphere, the apparent drawback of doing the same for the fuel is offset.

If that is one supposes it is important to minimize the slope. Given that the craft will be plowing through significant atmospheric densities at multiples of the speed of sound I suppose that overall one wants something like a Sears-Haack body (V-2 was a close approximation, with the flame of exhaust substituting for the trailing pointy end) and a fair approximation is achieved with a pointy nose cone and either a purely cylindrical body for most bulk, or a gradually expanding one as with Saturn V. Having the bottom flare out so the whole thing looks like a golf tee turned upside-down would hardly be anyone's recommendation--or would it?

One approach to drag reduction tried on some ICBM models (submarine launched, actually IIRC) is putting a spike on a rather blunt warhead; apparently the shock wave forms around the tip of the spike, and the body of the missile within the shock wave cone can deviate pretty far from supersonic ideal streamline shapes and not make much difference. The N series layout might be just fine if the lower rim of the lowest stage lies within that shock cone, with the upper stages serving as the "spike". We might then actually want to go for a wider flaring, which could be achieved by monkeying around with the fuel tank shape.

Now if i understand supersonic drag at all correctly, what happens first is the formation of shock waves, since these produce irreversible heating of the air they draw a lot of power out of the motion of the object, which takes the form of powerful drag pressures on the surfaces where the shocks form--on a rocket, the tip. Then air flows between the forward shock or shocks at subsonic but high speed (bearing in mind the speed of sound is raised by the shock heating) so decent shaping and smoothing of the surfaces behind the shock tip is still a design consideration. Somewhere more or less attached to the back end of the object is a countershock; along its conical surface the air that has been shock-accelerated by the forward shock wave or waves and raised in temperature and density as well "snaps back" to approximately ambient conditions, but irreversibly heated a bit (cooler than what was flowing past the body but warmer than before the body came by) and I would guess retaining some transferred momentum along the body's direction of motion as well. so there would be a plume of air trying to follow the rocket up (or would be, if it weren't blasted down by the rocket exhaust!:p) That sort of turbulent tail following an aircraft happens at subsonic speeds too.

The slope of the lower portion outward would be draggy in the subsonic flow entrained, and also I'd think another shock wave would form on its edge--but this might be mixed up with the formation of the countershock. Also the rocket engines (24 on "standard" N-1, 14 on my midsize mini version, 8 on a standard N-2) mounted on the rim would change the flow pattern to be different than if some magic exterior force were dragging the rocket along somehow, and more like there was an afterbody. I don't know just what effect the lack of rockets in the middle of the bottom disk would have but I'd expect it to be a turbulent low-pressure zone.

It would seem the drag must be higher than if the whole rocket occupied a uniform diameter cylinder, but that would clearly depend on just how long and broad that cylinder would be. I suppose one reason multi-stage rockets tend to be so very slim is that when the lowest stage, which is generally largest, sloughs off, the remainder is much squatter in proportion, and goes at an even higher Mach factor before the air drag becomes negligible too, so while broader proportions might be OK, they apply to the upper stack, not upper plus lower.

I will mention that the conical form of the N series lower stages actually sidesteps that consideration, in three ways--first because in the conical lower stages the proportions remain the same there; second because the broad base of each one is narrower than the prior stage so overall, with the upper cylindrical part becoming an increasingly large proportion of the height, overall the form is narrowing or anyway getting no worse, and finally because the spread-out form holds more volume per unit length the farther down you go, so that the conical stages are considerably shorter than they would be if fixed at some intermediate diameter.

Also that a lot of Soviet designs seem to violate the Western ideal of a long slim form one way or another; consider the conical, and angularly scalloped, form of the classic R-7.

Suggesting that rockets need not be as skinny as Western models tend to be (at least when stripped of the boosters or parallel liquid burning stages they tend more and more to be launched with) seems borne out by the relatively broad and short forms of the STS and Energia propellent tanks; with the same tank being driven through the air all the way to full orbital speed, it doesn't get relatively shorter.

So-the N form looks as though it must create somewhat more drag than say a Saturn rocket. But does anyone know how much worse it is? A small increment as I would guess, or a lot more? And how would it compare to say the STS tank, with its added interference from the boosters and the Orbiter itself, or even bare?

I'd be interested in a proof that the angle off the centerline could actually be greater, since that might allow for moving the kerosene fuel into complex-form non-spherical tanks under the oxygen sphere, and select a slope that right-sizes the upper stages, while allowing the broader based first stage to atmospherically brake and then parachute and rocket to a soft landing on the downrange steppes, to be recovered and reused.
 
I've read that the aerodynamics of the STS were absolutely terrible, but I have never seen numbers comparing the losses to air resistance of the STS versus, say, a Saturn V.

My instinct is that the N-1 has a less efficient shape than the Saturn V, which is a shame, because I find the N-1 a beautiful looking rocket (one reason why I always get involved in discussions of how to save it).

Unfortunately, I've never seen any numbers for how much energy the N-1 would lose to drag.

I don't think that atmospheric resistance is a significant problem during a launch though.

Also that a lot of Soviet designs seem to violate the Western ideal of a long slim form one way or another; consider the conical, and angularly scalloped, form of the classic R-7.

The N-1 and the Soyuz-scale R-7 are both unusual for Soviet rockets though. (And are both Korolev designs.) Other Soviet rockets tend to look more conventional.

Incidentally, anyone know what would happen if you put strap on tanks on the N-1 that gave it a cross section like the Soyuz rocket? I am thinking of it being a late improvement, after they've decreased the chances of engine shut downs, so they had the engine capacity to use more fuel and oxidizer. (Given how KORD worked, I cannot see how it would be a good idea to put booster stages like the Soyuz rocket had on an N-1, though if anyone can see how booster stages on an N-1 could work, I'd also be interesting to hear if they'd be useful.)

fasquardon
 
I've read that the aerodynamics of the STS were absolutely terrible, but I have never seen numbers comparing the losses to air resistance of the STS versus, say, a Saturn V....Unfortunately, I've never seen any numbers for how much energy the N-1 would lose to drag.
See here for some example numbers. The answer is that Shuttle is several times worse than Saturn V, but that the difference are also dwarfed by gravity drag losses and of course the main burn. I don't have numbers from N1, but I doubt it'll be out of that ballpark...

I don't think that atmospheric resistance is a significant problem during a launch though.
Pretty much, yeah.
 
See here for some example numbers. The answer is that Shuttle is several times worse than Saturn V, but that the difference are also dwarfed by gravity drag losses and of course the main burn. I don't have numbers from N1, but I doubt it'll be out of that

Huh. So the STS loses less energy to drag than any system that isn't a Saturn V on that list. Not what I would have expected.

I bet scale has something to do with the big boosters being less drag-limited.

fasquardon
 
...
My instinct is that the N-1 has a less efficient shape than the Saturn V, which is a shame, because I find the N-1 a beautiful looking rocket (one reason why I always get involved in discussions of how to save it).
I've obviously picked up an admiration for it myself. "Beautiful" is still not a word I'd pick for it. It looks goofy to me, but in a way that seems classically Russian as an onion dome church tower. And I love it for that! (And other things, that I've expressed at length in various places).
..The N-1 and the Soyuz-scale R-7 are both unusual for Soviet rockets though. (And are both Korolev designs.) Other Soviet rockets tend to look more conventional.
I get the same impression of a lovable doofyness and distinctly Slavic look from the Proton. I only hate Proton for the propellants it is designed to use, and could hardly use any alternative given the philosophy of its design (which relies on the fact that hydrazine and N2O2 oxidant require similar proportions of volume for a properly matched mix, hence tanks of similar volume. It also relies on none of its propellants being cryogenic).

The UR-700 on the other hand is simply an abomination before the Lord!:eek:
Incidentally, anyone know what would happen if you put strap on tanks on the N-1 that gave it a cross section like the Soyuz rocket? I am thinking of it being a late improvement, after they've decreased the chances of engine shut downs, so they had the engine capacity to use more fuel and oxidizer. (Given how KORD worked, I cannot see how it would be a good idea to put booster stages like the Soyuz rocket had on an N-1, though if anyone can see how booster stages on an N-1 could work, I'd also be interesting to hear if they'd be useful.)

fasquardon

I tend to quail at the idea of boosters attached to the sloping sides of the lower stages, but really I guess there is no reason they couldn't be attached, especially if they are liquid fueled but even solids can exhaust through a nozzle at an angle to their axis. Not that the Soviets are likely to use solid boosters anyway (though Gnom of course proves that they could, as do the Soyuz and proposed TKS launch escape systems, as well as the Soyuz and TKS landing rockets. Except for Gnom's these are all very short burning rockets of course, and even Gnom's would burn a lot more briefly than American or European or Japanese solid boosters.

Clearly any boosters attached to an N rocket base would have to finish their burn before the first stage does, or with it. Which implies though doesn't strictly require that their length be confined to the height of that stage, suggesting a rather squat form for their tankage or grain.
 
The UR-700 on the other hand is simply an abomination before the Lord!:eek:

The more I read about the development of the Proton and the development of the engines that would have powered the 1st stage of the UR-700, the more I think that actually building that rocket would have lead to disaster.

I tend to quail at the idea of boosters attached to the sloping sides of the lower stages, but really I guess there is no reason they couldn't be attached, especially if they are liquid fueled but even solids can exhaust through a nozzle at an angle to their axis. Not that the Soviets are likely to use solid boosters anyway (though Gnom of course proves that they could, as do the Soyuz and proposed TKS launch escape systems, as well as the Soyuz and TKS landing rockets. Except for Gnom's these are all very short burning rockets of course, and even Gnom's would burn a lot more briefly than American or European or Japanese solid boosters.

Clearly any boosters attached to an N rocket base would have to finish their burn before the first stage does, or with it. Which implies though doesn't strictly require that their length be confined to the height of that stage, suggesting a rather squat form for their tankage or grain.

The slope being steep enough to make it difficult to jettison strap-on boosters or drop tanks without damage to the 1st stage occurred to me also.

I don't think they'd even try solid booster rockets. The Soviets don't seem to have mastered high-energy solid fuels early enough to be tempted to use in space-going rocketry.

Like I say though, any sort of booster sounds like a bad idea. Drop tanks might be more practical though. My thought was that they might prove an economical way to increase the fuel & oxidizer load (and thus delta V) of the first stage.

"More practical" in this case does not mean "practical" though. It might just be easier to re-design the first stage around cylindrical tanks at the point when engine reliability had risen to the point where such a redesign would be useful.

fasquardon
 
So The Kremlin's Nuclear Sword on google books mentions the "little civil war" in chapter 5 "beyond parity". According to it, Ustinov and Yangel were part of the faction in the Soviet military-industrial complex who favored developing land-mobile solid fueled nuclear missiles with more advanced avionics (made possible by the integrated circuit's development) which could be programmed to guide the missile to different targets (allowing the Soviet strategic forces to be pivoted to target the USA or China depending on the circumstance).

Ustinov's faction was opposed by Chelomei, most of the RSVN's command structure and defense minister Andrei Grechko.

From the sound of it, if the Gnom had any potential, Ustinov would have backed it come hell or high water (and indeed, Ustinov did secure funds for the development of solid fueled land-mobile missiles when the Little Civil War ended in a compromise peace in 1969). So maybe Gnom didn't proceed because it could not live up to its promises?

On the other hand, it does sound like if Gnom had fulfilled its promises in the mid 60s, Yangel and Ustinov would have triumphed against Chelomei and Grechko.

As I stated in another thread the early Protons were very unreliable and this led to some catastrophic failures and extensive contamination of the steppe.

What actually made the early Protons so unreliable? Bad luck? Bad management? Bad design? Something else?

fasquardon
 
New aircraft designs just about always have a rate of crashes far worse than they wind up suffering in their careers. This is a combination of inexperience of structural details, their interactions, and operation. Saturn largely avoided this only by means of testing everything, at great cost and taking considerable time, and even so, "Pogo" was a serious problem.
 
New aircraft designs just about always have a rate of crashes far worse than they wind up suffering in their careers. This is a combination of inexperience of structural details, their interactions, and operation. Saturn largely avoided this only by means of testing everything, at great cost and taking considerable time, and even so, "Pogo" was a serious problem.

So you reckon any Soviet launcher in the same weight class as the Proton would have a similar early reliability record?

fasquardon
 

Archibald

Banned
What actually made the early Protons so unreliable?

A very, very rushed development. AFAIK Proton development was authorized in 1962 with the first flight happening in 1965 and the bugs were not ironed out. Then because the Proton was a major asset in the Soviet robotic lunar program there was no time to make a break and fix the flaws. Only after loosing a great number of lunar spaceships and Mars probes did the Soviet leadership allowed a six-month break to cure the design mistakes. After that the Proton flew much more reliably.
 
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