How does the M-1 control it's flight? Do the engines gimbal or are there verniers?
Also, since i'm building Zarya to a scale where the reentry module is 1.25 meters wide, would the upper stage be 2.5 meters or 1.875 meters?
EDIT: my current plan is to have the upper stage be 1.875, with the second stage being a 1.875-2.5m cone, and the first stage being 2.5-3.75m
The
first post to mention Zarya mentioned a 2 meter diameter for the capsule as I was recently reminded
here. OTL Soyuz is 2.17 meters; the extra 17 centimeters does not sound dramatic but assuming the capsules are the same proportions, represents a 25 percent increase in volume. That is, Zarya would have 80 percent the cubic inside its skin--maybe less habitable volume if the shell thickness is the same or greater as seems not unlikely. Also some pictures seemed to show a somewhat shorter-looking capsule, so the height might not be in proportion and the space inside more like the 66 percent that accounts for it being a strictly 2-cosmonaut vehicle only. I hope it is not much shorter in proportion because the linear dimensions inside will be tight enough; Soyuz return capsules are not famous for their spaciousness!
I'd have to review whether any mission has ever had two cosmonauts and no form of orbital module, counting that bizarre cylindrical fabric/cage airlock as one of those, sort of. Anyway they had an unsatisfactory experience with that thing (although it clearly would have been superior to the much smaller thing the first OTL Soviet spacewalker, IIRC Leonov, used to exit (and almost fail to) reenter his Voshkhod. I think the airlock is meant to be the same design but bigger.
I noticed your Kerbal models had a hatch on top of the reentry capsules, this would only be for missions where there were modules of some kind attached on the top.
I figure if someone made a mini-Zarya for just one person then the volume would be halved when the diameter was reduced to 1.6 meters, so 1.25 meters would probably be downright claustrophobic! I think I can visualize sitting not too terribly uncomfortably in within a meter-diameter sphere, especially if I were weightless, but it seems a lot to ask of a cosmonaut! There's a reason Mercury missions were never very long, whereas Voshkhod was a horrible kludge of an idea.
Looking at my little sketch of 2 stages of the spherical-tank rockets, I think there is just barely room for a third stage on the same lines before the cone constricts to 2 meters diameter; in reality if the sphere-tank format had been the model for M-1, I suppose the third stage would go over to cylindrical tanks and straight sides.
Hi guys,
Sorry, just a couple of clarifications on the M-1. First up I spotted an error in the Wiki, which showed the 2nd stage (Blok-G) VM-202 engine having a thrust of 50kN. In fact this should be 1100kN!
I've corrected this.
I was wondering about that, a lot. The Blok-G engine seemed downright superior to the D-Blok and almost precisely the same thrust so I wondered why carry over the old engine at all?
That the first stage would mass something like 4.6 times the second but use 12 times the thrust also seemed odd; now we see it much closer to being in proportion--still high, but you need extra thrust for initial launch, what with atmospheric drag, impediment of thrust, and the basic task of getting the whole stack moving briskly. I gather Soviet designers tended to favor using a whole lot of thrust for initial boost, leading to pretty high G's at lower stage burnouts, and chalked it up to that.
Also noted on the Wiki (which I must admit I'd forgotten) is that the "1st Stage" was originally intended to consist of 3 identical cores strapped together (Blok-A, B and V), each with 2x VM-12 engines. I did this to allow stages of reasonable length whilst keeping a maximum 4.15m diameter (imagine Soyuz/R-7 with 3 boosters and no central core). However, this isn't mentioned in the posts, and I'm not sure now if it was still needed (sorry, my notes got a little confusing!), as a quick check now shows the 1st stage being a cylinder 25m long at a 4.5m diameter, which isn't unreasonable. Monolithic would certainly be simpler for staging, so I could go either way.
Making a triplet of 3 Semyorka-style booster stages does seem kind of goofy; either we'd have three cylinders yoked together with an awkward gap running up the center, or they'd have a triangular inner portion of their circumferences allowing fluids to use that inner volume (which is not large, we could easily sacrifice it to keep the units cylindrical, as it would be full of essentially massless air--it isn't massless but it would not mass much and would presumably be vacated as the rocket rises). Then, we'd wonder, why have that triple partition in the middle at all, that's just useless mass separating identical components. Three seems awkward; it doesn't give any great options in an engine-out situation for instance.
I was wondering if you'd simply want to gang the three around the second stage so all four units have their bottoms on the ground--but then I saw that if the central, second stage had the same diameter as the outer ones it would wind up being only 2/3 as long!
Not to worry, I thought, the third stage will fill in the gap--nope, not even close. Clearly to do this the central stage would have to have a smaller diameter, which works I guess for three outer stages, and might for four, and perhaps five, but not six. It is a very odd layout regardless. I of course wondered why not just make the second stage identical to the three outer boosters, except it has a single upper-atmosphere/vacuum optimized engine instead of two lower-atmosphere ones. But a quick visit to Silverbird calculator showed the error of that--the payload to 250 km from Baikonur (aka Tyurtam) was drastically lower with the bigger central stage.
So we are left with arranging the three boosters on the ground by themselves, and putting the second stage where it belongs up higher. Since the boosters are presumably three rather than integrated into one stage because they are at maximum diameter (and maybe length) for Soviet rail transport, I don't see why not make the upper stage the same diameter for uniformity of tooling.
The straightforward way to arrange three booster stages is to run them in a line; this would make the rocket look pretty American unfortunately.
Grouping them in a triangle would be possible and cool-looking I guess. We might then just as well upgrade to four in a square (the only way to do four I guess)--five in a pentagon or alternatively in a cross. Six in a hexagon would leave a hole through which a standard diameter stage would slip right down into unless we filled it with a seventh booster.
I looked at that; that is 7 of your boosters instead of 3, with another stage just like them on top of the central booster (with two of the upper atmosphere engines instead of lower atmo versions, but the vacuum ISPs given are the same and presumably the weights are similar--I guess the high altitude version might be heavier due to a longer nozzle, but not by a lot I suppose) and finally the second stage you have on the Wiki as a third stage. Silverbird estimates some 28 tons to that standard 250 km, 55 degree inclination orbit. I caution I didn't use any weights for fairings, and I suppose the central booster stage needs some reinforcement, and maybe the two uppers do too since the payload is triple or more the given M-1 Zarya load to standard. Also for the stage masses as given for M-1 Silverbird gives 10 tons (without the "Signal" third stage, which appears to be the same exact stage Mishin added to the R-6 to launch the first series of one-cosmonaut Zaryas) not the 8 you cautiously give. Reducing the 28 ton estimate proportionally brings it down to just 22.4 tons.
Still, such a modular system clearly can overlap Minerva turf and surpass the Proton. Possibly by optimizing the sizes of the two upper stages better, the optimized payload can be more than 23 tons, perhaps even surpass the Silverbird estimate and reach 30 tons. At the other end of the scale I figured, not too surprisingly, that a single one of your M-1 boosters, topped by a second stage just 1/3 the mass of your given second stage, would put some 3 tons in orbit. So on a somewhat smaller scale, the three-booster model of M-1 suggests that Mishin's rockets can offer the sort of flexibility Minerva does the Americans, with various mixes of boosters--1, 3, 4, 5, and 7, and trimming upper stages of standard diameter to optimize toward various goals.
That would not enable a Lunar mission more ambitious than a flyby in a single launch of course.
Incidentally, the potential conical shape of M-1 (and quite possibly the OTL R-7 boosters and N-1) would be inspiration from Helmut Groettrup's rocket designs in the 1950s, e.g. the
G-4.
Mark Wade says that the G-4 "inspired" both the Semyorka and N-1, but in the latter case I don't see how, except that perhaps the Soviets got used to the conical idea. A specific stroke of genius Wade attributes to Gröttrup is the matter of moving the oxygen tank up to the top of the stage to get it away from the engines and other infrastructure at the bottom, which apparently suffered from being chilled by the LOX. Especially given the conical structure (which has no apparent reason in the G-4 except one might guess aerodynamics) that means the greater volume of propellant, and the one that needs insulation, is being squeezed into the narrower part of the enclosure, raising the surface area to be insulated (or alternatively the rate of heating hence boil-off of the LOX, and putting the frost zone it creates higher up where chunks of ice falling off can do more damage a la STS Columbia. I'm not saying the man was stupid; presumably benefits offset these obvious costs.
But I checked a description of the N-1 and indeed as common sense indicated, the oxygen tank, being the larger one, is on the bottom, undoing the concept of Gröttrup's that Wade highlights as crucial and one would infer, "inspirational." With spherical tanks it has to be that way.
Well, one could imagine the lowest stage reversing it, making the cone taper with its projected point on the bottom instead of the top, then if the upper stages are LOX-down, the whole rocket would be more of a spindle shape, which I think might make for improved supersonic aerodynamics, approximating a
Sears-Haack Body. Sort of! Putting the first stage booster LOX tank on the top would define the maximum radius of the body, and since the second stage is necessarily lower in mass (by far, typically) its spherical oxy tank, which is the next "checkpoint" in the radius, will be significantly lower in radius, meaning to fit neatly in a proper S-H body it would have to be a certain distance up from the "equator" of the first stage LOX tank. Maybe this works out OK because the radius of that big tank will account for some of the upper half of the S-H body, then a gap for the upper stage engine(s) and clearance, then the radius of the second stage LOX tank...it might work out OK or we might even have the upper half of the body being stretched longer than optimal rather than too short as I first feared. The taper by then ought to fit the second stage fuel tank pretty well I guess, and if not we can fudge it one way or the other.
The upper stack beyond the second stage seems not too likely to fit neatly in the S-H envelope though; I would guess at some point you'd want to stop tapering and go with a uniform cylinder from there up, or anyway slow or suspend the taper for a while. So you'd still get extra shock waves, maybe overall worse than a simple cylinder would have given.
So inverting the first stage to conform with Gröttrup's notion would only seem advisable if the shock effects we avoid on the bottom offset the extra ones we probably get up top; since the top is going to bear the brunt of the impact of shock waves, I'd suspect not. Note how this notion also puts the second stage engines and so forth between two LOX tanks! Although there would be a good gap between them.
Raising the LOX tank a la Gröttrup also defies thermodynamics a bit in that you're putting the coldest thing up high, where the chilled air from it flows down and chills everything below while bringing in fresh warm air to continue boiling the LOX; putting it down low seems sensible--also it's dense stuff while kerosene is less so, so in terms of stacking masses putting the LOX below the fuel seems to make more sense too.
So anyway, given that Korolev OTL and perhaps Mishin here defies the single greatest accomplishment of Gröttrup that Wade cites, it seems like a stretch to say that the G-4 inspires the N-1 at all. Except maybe in the limited sense that conical rockets seemed less outlandish to Soviet designers familiar with Gröttrup's work than they would to Americans.
But of course, the American general public, as opposed to professional rocket engineers, were exposed to ideas of how rockets should look in the "Collier Space Program" and Disney's related efforts to popularize Von Braun's vision, and those vintage 1950s illustrations typically did show big-bottomed conical, half-spindle in fact, giant rockets with spaceplanes on top, more like the N-1 than the Saturn V!
Oh well, whatever the antecedents might be, the question now is which of these approaches (or a third) is most sensible for Mishin to have pushed through in the mid-60s. If you, the author nixonshead, like the Gothic look of the N-1, you are not alone! OTOH your onboard tech advisor with actual academic certification in rocket history and/or design (I believe e of pi has an actual rocket design degree, but I can well believe Workable Goblin does too, or anyway has a whole lot of serious academic technical history under his belt I can only envy) points out the drawbacks, technically. You probably aren't planning to have Mishin succeed in any scheme to make the first stages recoverable and reusable (if this were possible the transportation hurdles would presumably be well overcome--it's going to take some combination of airship or helicopter to go get spend stages from the steppes for sure) so there goes one of the possible advantages of the big-bottomed arrangement.
The modular scheme is probably a bit less mass-efficient, but I've suggested how Mishin might be able to sell it as the basis of a Soviet answer to Minerva, enabling a range of launch options with common hardware. If the modules are sized to fit on the railways then the logistics of producing them are largely solved.
Vice versa--if you settle on the tapered stages with spherical tanks, and we dismiss all notions of Soviet airship cargo haulers, which is only sensible given the limited deviation of this TL from ours--you are then pretty much stuck with the idea that the big stages are being produced right there at Tyuratam. Which is perfectly well in line with how the Soviets tended to do things; I think that is indeed how they made the N-1 OTL after all.
That would imply that it would be very difficult to launch an M series rocket from any other site than Tyuratam.