A successful, but late, N-1 rocket

[fasquardon]

So we've discussed the Soviet N-1 moon rocket before, but usually those discussions have focused on the rocket succeeding in the 60s, allowing the Soviets to either win the moon race or at least score a close second... What I'd like to do here, is ignore the 60s, and focus on the results of the N-1 becoming a successful rocket well after the US has decisively won the moon race.

As a possible PoD, let's say the 4th attempted launch on November 23 1972 is successful due to ground control separating the malfunctioning first stage early, meaning the upper stages are still on the way to orbit when the first stage explodes 107 seconds into launch.

Let's say this success is enough that the Soviets continue serious testing of the N-1, but not great enough to save the Soviet Lunar program. By 1975, let's suppose that the Soviets have a working Saturn V class rocket, but no program to use the rocket in.

What happens next?

Given how close the N-1 came to becoming the launcher for the Soviet space shuttle OTL, I would guess that Glushko, if he still gains overall control of the Space Programs of the SU, would be forced to use the rocket TTL as his shuttle launcher.

Given that the Soviets were, at the time, looking into making their smaller boosters more efficient and economical at this time, I would suspect that the smaller versions of the N-1, the N-11 and N-111, would have a chance to replace the Proton and R-7 rockets as well (OTL, what became Zenit was supposed to replace these two, though it became something in between an R-7 and a Proton in the end). Particularly if they could be automated to a similar degree to the Zenits.

I suspect that Glushko would seek to "upgrade" the N-1 with his own engines if he is forced to use it. The rocket getting RD-170 engines in the mid-80s could help with reliability simply due to reducing the engine count. I'm not sure if the RD-170 would have any other advantage over the NK-33 though...

I suspect that the American lead in H2/LOX propulsion would lead to the politburo insisting that the Soviet Space Program get into using liquid hydrogen themselves, just as OTL. That might result in the N-1 gaining some hydrogen upper stages.

Also, what might the Soviets do in the 70s and 80s if they're not spending pretty much their whole space budget on building a rocket for their shuttle? More probes? More interesting manned activity in space?

And what do the Soviets do if they have an Energia-class launcher (actually, the N-1 was supposed to have been more powerful than Energia) 13 years earlier than OTL?

fasquardon

 

[Bahamut-255]

There's a serious problem here. The N1-L3 Programme was finally approved in 1965 as a Counter-Measure against the US Apollo/Saturn Programme, thus once Apollo 11 succeeded the Political Desire to continue essentially evaporated. While it is true that the N1 had a number of applications it could be used for - Manned Lunar Missions, Large Space Station, Heavy Interplanetary probes, and EOR Manned Mars Missions - it was originally designed without a clear plan of what to use it for.

Furthermore, by the time the N1 was ready for its first Test Flight, it was an already-obsolete design. The Spherical Tanks were chosen for having the greatest volumetric efficiency, but made uprating the LV difficult at best (by LV Standards) so they had to get seriously 'creative' with squeezing more out of it. Closed-Cycle Engines, Supercooled Propellants, Material Changes where possible. The other downside was that by the top of the Block V (3rd Stage) the diameter was down from 15.8m to ~4.4m IIRC, meaning the dimensions of the payload could well have faced a serious constraint there.

But let's assume that yes, they do get a working N1 by the mid-late 1970's.

At this point the NK-15 would have been replaced by the NK-33 which was actually ready by the end of 1972 but there was no time to replace them on the N1-7L (the 4th and OTL Final Test launch). This combined with other modifications from lessons learned during the previous flights would get you at least the N1F Series. The problem now is, what to use it for? It's very poorly suited for any kind of Shuttle-Equivalent for the reasons I've given and I can't see it being used for that even if they give Buran the go-ahead. In fact, if Buran is approved then the N1, I think, is doomed.

So IMHO, to keep the N1, you can't have Buran. So now the question is, what do they do instead?

One answer was the L3M Programme. A plan developed by Mishin's TsKBEM Bureau to 'leapfrog' the US in the Manned Lunar Programme had been in the works at a low level for a time, the L3M-1970 and L3M 1972 for extended-duration Manned Lunar Exploration. And with either the N1F-Sr or N1M - both of which were rather similar in capability but different in payload dimension limits - to support that type of mission, there is a chance they could pull it off.

Skylab-Sized Stations are another possibility. The N1 was suited to such a task and they did have plans for such a station known as the TKS Heavy Space Station which culminated into the MKBS Station - although these stations would need to be prepared in the N1 Facilities as opposed to Chelomei's OKB-52 Facilities - which enjoyed a self-contained Environmental Control System, independent Diesel Generators, and could check the payloads out completely prior to their launch, as it was used for Military Payloads - which could well harm its viability.

By not spending all their money on replicating the N1 (to an extent) they could have the funds for one or more of what's been described, but whether they'll have said funds at all is another matter.

I suspect that Glushko would seek to "upgrade" the N-1 with his own engines if he is forced to use it. The rocket getting RD-170 engines in the mid-80s could help with reliability simply due to reducing the engine count. I'm not sure if the RD-170 would have any other advantage over the NK-33 though...

The RD-170 developed 740,000 Kgf (~7,260 KN) Thrust through its four combustion chambers at Sea-Level with an Isp of 309s that climbed to 337s in a vacuum, versus ~1,510 KN and 298-331s Isp for the NK-33. That is quite a difference assuming he gets to make it.

 

[fasquardon]

Furthermore, by the time the N1 was ready for its first Test Flight, it was an already-obsolete design. The Spherical Tanks were chosen for having the greatest volumetric efficiency, but made uprating the LV difficult at best (by LV Standards) so they had to get seriously 'creative' with squeezing more out of it. Closed-Cycle Engines, Supercooled Propellants, Material Changes where possible. The other downside was that by the top of the Block V (3rd Stage) the diameter was down from 15.8m to ~4.4m IIRC, meaning the dimensions of the payload could well have faced a serious constraint there.

I am really not convinced that the difficulty of uprating the N-1 was a real disadvantage - if the Soviets aren't going to the moon, the N-1 is over-powered for any other conceivable job. Arguably, the N-1 would have gotten better if they'd downrated it. Particularly, IMO, by dropping the super-cooling.

As with the Saturn V, they had proven engine upgrades that never got the chance to fly, so there is performance to be gained by improving the engine thrust and chamber pressure. Also, they could move to waffle-grid tank walls, which would save weight. And they could certainly improve the performance of KORD (as well as the rest of the guidance and avionics) by a large margin. Improved quality control and more experience building and flying N-1s would also help raise reliability and allow them to take some of the redundant engine pairs off the rocket. So there is some scope for upgrades.

Also, the 2nd, 3rd and 4th stage could be replaced by hydrogen-LOX stages, which could, if desired, be used as a means of increasing the payload. (Though at that point, we're talking less about an N-1 and more an N-1 first stage being used as the booster for an entirely new rocket.)

Also, one could add in re-useability to the first stage (possibly even the higher stages too) which would decrease performance, but offer cost reductions.

With respect to the diameter of the top of the rocket - 4.4m is still fairly wide as rockets go. The Buran's cargo bay was 4.6m diameter. The N-1 could certainly manage wider payload shrouds.

The problem now is, what to use it for? It's very poorly suited for any kind of Shuttle-Equivalent for the reasons I've given and I can't see it being used for that even if they give Buran the go-ahead. In fact, if Buran is approved then the N1, I think, is doomed.

The engineers at the time seemed to have thought they could launch something like the US shuttle on top of an N-1. Now, the engineers at the time may have been wrong.

What in your view makes the N-1 so unsuitable? That the top of the rocket was too narrow?

The RD-170 developed 740,000 Kgf (~7,260 KN) Thrust through its four combustion chambers at Sea-Level with an Isp of 309s that climbed to 337s in a vacuum, versus ~1,510 KN and 298-331s Isp for the NK-33. That is quite a difference assuming he gets to make it.

The NK-33 had a better thrust-to-weight ratio. Otherwise the RD-170 is a superior engine.

I think the RD-170 was also designed from the start to have a longer useful life (so engines could be re-used). I'm sure I remember reading something about the NK-33 actually being fairly re-useable, but I have no idea where I read that and I have no idea if the engine would have a working life anywhere close to that of the RD-170.

Do you think switching to the RD-170 would offer great improvements to the performance of the first stage?

I once calculated the performance of an Energia resulting from replacing the RD-170 with the high-thrust version of the NK-33 - I may have messed up my math, but as far as I could figure, it was pretty much a wash - the performance of the vehicle was similar overall.

Also, which engine was more expensive to manufacture? Fuel is darn cheap, rocket engines less so. If the more efficient engine is sufficiently expensive, it could still be the worse choice...

fasquardon

 

[e of pi]

Redesigning for the RD-170 would mean changing both the first and second stage thrust structures--both were using variants on the NK-15/33 and you'll need to cut the number of engines on each by a factor of four, while redesigning plumbing and the like. This is in a sense a simplification, but it'll mean a large and costly redesign and re-qualification to accomplish, and if the RD-170 doesn't actually offer much of a performance advantage over the NK-33, then why bother? (Of course, the answer could easily be "Glushko holds grudges and not-invented-here" syndrome, but at that point if you're redesigning so much, why not just make new tanks too?)

As for mounting Buran on it, I'm not sure about the feasibility without adding very large stabilizing fins to the N1 aft--the wings on Buran will move the center of pressure rather far forward without additional counterbalancing surfaces further aft. Given where it stages in the atmosphere, a similar issue may exist for the second stage, so that may also require large fins added, depending on which stages Buran retains and where it sits on the stack--on the top or beside the final stages.

 

[Bahamut-255]

I am really not convinced that the difficulty of uprating the N-1 was a real disadvantage - if the Soviets aren't going to the moon, the N-1 is over-powered for any other conceivable job. Arguably, the N-1 would have gotten better if they'd downrated it. Particularly, IMO, by dropping the super-cooling.

Propellant Super-Cooling was an addition to the N1F Series (AFAIK the first four launches didn't feature this) for the 10% Payload Increase needed for even the basic L3 Mission. The US Skylab was about 77,000 Kg and given that Soviet Equipment tended to be heavier for the same capability, about 95,000 Kg for their equivalent isn't unreasonable.

Though without something like Manned Lunar Missions or super-heavy GEO/BEO Payloads, I don't think the flight rate would be enough to justify keeping all the facilities for the N1 without an N11. And by the time the N1 could be made reliable enough for regular use - and thus give extra weight for an N11 - the UR-500/Proton had more or less cleared its State Trial Period having attained a reliability rating comparable to US LVs.

Also, the 2nd, 3rd and 4th stage could be replaced by hydrogen-LOX stages, which could, if desired, be used as a means of increasing the payload. (Though at that point, we're talking less about an N-1 and more an N-1 first stage being used as the booster for an entirely new rocket.)

Also, one could add in re-useability to the first stage (possibly even the higher stages too) which would decrease performance, but offer cost reductions.

Which is also what I meant by 'difficult to uprate'. As substantial changes like this do effectively amount to designing an entirely new LV with all the cost and risk associated with it. And after spending some 10 years getting the LOX/Kerosene Blocks A, B & V to work well...

Hence why using LOX/LH2 for just what went on top - i.e. Blocks G & D to S & R or Sr - of that tends to have more favour IMHO, being simpler to implement, and where the LOX/LH2 Benefit is much greater.

The NK-33 had a better thrust-to-weight ratio. Otherwise the RD-170 is a superior engine.

I think the RD-170 was also designed from the start to have a longer useful life (so engines could be re-used). I'm sure I remember reading something about the NK-33 actually being fairly re-useable, but I have no idea where I read that and I have no idea if the engine would have a working life anywhere close to that of the RD-170.

Do you think switching to the RD-170 would offer great improvements to the performance of the first stage?

~133:1 T/M Ratio IIRC, the highest number ever achieved. And the when the NK-33 was being designed, Kuznetsov had concluded that the only way he could assure them as Expendable Engines was by designing, building, and testing them as Reusable Units, he was able to get 1,200s firing time in multiple burns to the best of my knowledge.

The RD-170 was found to be capable of perhaps 3,800s firing time in its Ground Tests. That's up to 27 uses from it in Energia/Buran/Zenit.

I once calculated the performance of an Energia resulting from replacing the RD-170 with the high-thrust version of the NK-33 - I may have messed up my math, but as far as I could figure, it was pretty much a wash - the performance of the vehicle was similar overall.

Also, which engine was more expensive to manufacture? Fuel is darn cheap, rocket engines less so. If the more efficient engine is sufficiently expensive, it could still be the worse choice...

fasquardon

Well individually the NK-33 would be the cheaper engine, though far fewer RD-170s are needed. And high-altitude single-chamber variants for the Block B are also more than viable if you're replacing the Block A engines. Question here is: Is 6 RD-170s cheaper than 30 NK-33s?


One other thing to consider. What could they use the N1 for? How often? To the best of my knowledge, one critical reason that Energia/Buran was abandoned after Buran flew was that they had NO missions for it. And without that, there was little-to-no reason for them to keep it.

 

[fasquardon]

Redesigning for the RD-170 would mean changing both the first and second stage thrust structures--both were using variants on the NK-15/33 and you'll need to cut the number of engines on each by a factor of four, while redesigning plumbing and the like. This is in a sense a simplification, but it'll mean a large and costly redesign and re-qualification to accomplish, and if the RD-170 doesn't actually offer much of a performance advantage over the NK-33, then why bother? (Of course, the answer could easily be "Glushko holds grudges and not-invented-here" syndrome, but at that point if you're redesigning so much, why not just make new tanks too?)

Hm, good point.

As for mounting Buran on it, I'm not sure about the feasibility without adding very large stabilizing fins to the N1 aft--the wings on Buran will move the center of pressure rather far forward without additional counterbalancing surfaces further aft. Given where it stages in the atmosphere, a similar issue may exist for the second stage, so that may also require large fins added, depending on which stages Buran retains and where it sits on the stack--on the top or beside the final stages.

Is it possible to fold the wings on a 70-80 tonne orbiter? Or would re-entry stresses be too much for the joints?

The other alternative is to go with some sort of wingless lifting body design like Glushko first imagined (though his first design was fairly impractical).

Propellant Super-Cooling was an addition to the N1F Series (AFAIK the first four launches didn't feature this) for the 10% Payload Increase needed for even the basic L3 Mission. The US Skylab was about 77,000 Kg and given that Soviet Equipment tended to be heavier for the same capability, about 95,000 Kg for their equivalent isn't unreasonable.

18 tonnes heavier for the same capability? I have difficulty seeing it.

Though without something like Manned Lunar Missions or super-heavy GEO/BEO Payloads, I don't think the flight rate would be enough to justify keeping all the facilities for the N1 without an N11. And by the time the N1 could be made reliable enough for regular use - and thus give extra weight for an N11 - the UR-500/Proton had more or less cleared its State Trial Period having attained a reliability rating comparable to US LVs.

I think being used some sort of shuttle program would be needed to keep the N-1 flying regularly. I can't see anything else fitting the bill, and even then, because the Soviets would be less dependent on their shuttle, I really have difficulty seeing them ever flying something in the STS/Buran class regularly.

A big bus like the Buran has real uses, to be sure, but I really have difficulty seeing why you'd need more than 1 or 2 big bus missions in a year unless you are going into complete wank territory... And at that point, the launch rate is so low I think it would only be practical to keep it on as a prestige project.

So maybe keeping the N-1 and successfully using it to launch an alt-Buran would just lead to the Soviets abandoning that approach earlier.

With regards to the N-11 replacing the Proton, the political pressure to move away from toxic propellants was pretty strong. OTL, the thing that saved the Proton was how long it took to develop the RD-170 (so Zenit could fly) and the Soviet Union collapsing just as the Zenit was coming online... If the N-11 looked viable in 1975, I suspect we'd have seen the Proton phased out fairly quickly. Particularly if a higher degree of automation was found to be possible (reducing the number of staff needed on the launch pad was Zenit's biggest advantage).

I suspect that the N-111 will always be doomed with a PoD in the 70s. The R-7 is very established and can, in any case, be upgraded to lower costs/launch or increase capacity. And as you say, the highest stages of the N-1 are the ones most likely to be replaced by hydrogen-LOX stages - which means that the engineers would be expecting to lose most of the commonality between the N-1 and the N-111 by the 80s.

I wonder if the N-1 first stage could be turned into a re-useable stage-and-a-half launcher like the was proposed for Saturn V first stage? The payload fraction would be poor, but it might be a good way to get economies of scale...

And the when the NK-33 was being designed, Kuznetsov had concluded that the only way he could assure them as Expendable Engines was by designing, building, and testing them as Reusable Units, he was able to get 1,200s firing time in multiple burns to the best of my knowledge.

The RD-170 was found to be capable of perhaps 3,800s firing time in its Ground Tests. That's up to 27 uses from it in Energia/Buran/Zenit.

Very interesting...

Well individually the NK-33 would be the cheaper engine, though far fewer RD-170s are needed. And high-altitude single-chamber variants for the Block B are also more than viable if you're replacing the Block A engines. Question here is: Is 6 RD-170s cheaper than 30 NK-33s?

Well, prices for re-conditioned NK-33s these days seem to be around 1.1 million USD/engine, but I'm not clear if that includes reconditioning costs or not. For RD-180s, the half-size offspring of the RD-170, Energomash committed to provide 101 engines for a fixed price of 1 billion USD. So that is around 19 million USD per RD-170 equivalent pair. So 30 NK-33s cost around 33 million USD while 12 RD-180s (which I am assuming would cost the same as 6 RD-170s) cost around 114 million USD.

But... I have no idea if the prices for the surplus NK-33s reflects the cost of manufacturing new ones and assuming that two RD-180s are equivalent to 1 RD-170 may be a poor assumption.

Certainly, a big part of the costs of any rocket engine is the development cost - and the NK-33 was pretty much complete by the time the Soviets abandoned them - the ones being used today have proven quite reliable, considering they are over 40 years old. In contrast, the RD-170 had all its costs ahead of it in 1972...

EDIT: So calculating from the above prices and a total firing time/engine of 1200s for the NK-33 and 3800s for the RD-170, assuming total re-use of the engine and no reconditioning costs, the cost for each 125 second N-1 1st stage burn would be: 3.7 mil. USD for the NK-33 and 3.8 mil. USD for the RD-170. For the NK-33, that price/launch would drop significantly if the total firing time of the engine can be bumped up even another 50 seconds...

Of course, reconditioning costs are not negligible. I suspect the NK-33 having a shorter working life would mean its reconditioning costs were slightly lower than those of the RD-170, but that is going from a layman's understanding of American experience with completely different engines... So... My suspicions may be dead wrong.

fasquardon

 

[e of pi]

Another question is recovery--are you planning on recovering the first stage? I'd assume you have to be if you're going to use the RD-170s more than once. Parachutes, wings...? If you're recovering, that's yet more changes from the "stock" N-1--and more argument for building a new vehicle Glushko wants to do anyway--and if you're not then the number of reuses of the RD-170 vs the NK-33 is irrelevant anyway: anything more than the number required for testing and a single expendable use is only margin.

As for folding the wings...I'm not sure. The LKS proposal used them on some versions--probably with a similar aim of reducing center-of-pressure instability on the Proton LV--but as deployment events go, that's a biggie. It's not impossible to simply beef up the joints to take the load even of an 80 ton orbiter, but if I was faced with designing it, it's not an option I'd prefer.

 

[Archibald]

My TL just deal with that https://www.alternatehistory.com/forum/threads/explorers-ad-astra.366697/
NASA scraps the shuttle, USSR scrap Buran and Energia.
NASA place a handful of Saturn V in long time mothball - so USSR decides to keep the N-1 and iron out the kinks.
Glushko is out, Chertok replace Mishin at OKB-1.

November 1972 flight test still a failure as per OTL, but next test (vehicle 9L) in August 1974 works better and send a complete lunar stack - unmanned - up to the lunar surface the exact day Nixon resing in shame over the Watergate (August 9, 1974).
Next shot (10L) send an enormous (22 tons !) Mars rover to the red planet - although it fails on the surface. http://www.astronautix.com/craft/mars5nm.htm#more

As for long term payloads - the MKBS giant space station, a project much more ambitious than OTL Mir

 

[fasquardon]

Glushko is out, Chertok replace Mishin at OKB-1.

Hmm. I don't think I've seen Chertok used in an AH before. Interesting.

Another question is recovery--are you planning on recovering the first stage? I'd assume you have to be if you're going to use the RD-170s more than once. Parachutes, wings...? If you're recovering, that's yet more changes from the "stock" N-1--and more argument for building a new vehicle Glushko wants to do anyway--and if you're not then the number of reuses of the RD-170 vs the NK-33 is irrelevant anyway: anything more than the number required for testing and a single expendable use is only margin.

Mostly I was looking at costs in the event of 100% first stage recovery since it would give the more expensive but longer lasting RD-170 an advantage.

On a slightly different topic, do people think the N-1 was significantly less upgradable than the Saturn V? I notice that discussions on continuing Saturn V use touch on all sorts of upgrades that were considered - while clearly stage stretches and adding strap-on boosters is more difficult on the N-1, were all of the other kinds of upgrades to the Saturn V similarly less practical to apply to the N-1? And if the N-1 is just a beast to upgrade right across the board, what made it so?

fasquardon

 

[Dayton Kitchens]

Hmm. I don't think I've seen Chertok used in an AH before. Interesting.



Mostly I was looking at costs in the event of 100% first stage recovery since it would give the more expensive but longer lasting RD-170 an advantage.

On a slightly different topic, do people think the N-1 was significantly less upgradable than the Saturn V? I notice that discussions on continuing Saturn V use touch on all sorts of upgrades that were considered - while clearly stage stretches and adding strap-on boosters is more difficult on the N-1, were all of the other kinds of upgrades to the Saturn V similarly less practical to apply to the N-1? And if the N-1 is just a beast to upgrade right across the board, what made it so?

The huge number of first stage engines. Thirty IIRC as opposed to five on the Saturn V. And the Saturn V really only needed four. More engines is more things to go wrong.

 

[Bahamut-255]

The huge number of first stage engines. Thirty IIRC as opposed to five on the Saturn V. And the Saturn V really only needed four. More engines is more things to go wrong.

Actually at some 2,750 Tonnes give or take, and a T/M Ratio of about 1.26:1 at lift-off. The Saturn V needed all five of its F-1 Engines working to get off the ground in any appreciable time.

And this came from a difference in philosophy and circumstance. In the US, the F-1 had been in development since 1959 for if such an engine were ever needed, so it was already part of the way to being ready when the Saturn V was selected as the LV for Apollo/Saturn. The USSR had no such engine that could be ready in time so opted to mature the 150-Tonne Class engine instead, requiring a very large number but offering engine-out capability - up to four at the moment of launch in the N-1.

IMHO, it wasn't the engine count that was the problem, but the difference in funding, testing, quality assurance, and simple priority that brought down the N-1 IOTL.

 

[Archibald]

Well, Glushko refused to design a "Soviet F-1" because he felt storable propellants were better, while Korolev wanted LOX/kerosene. Korolev had no other choice to pick a jet engine manufacturer - Kuznetsov.
The great irony is that Glushko did build his F-1, storable engine - the RD-270 was tested after 1970.

 

[fasquardon]

The huge number of first stage engines. Thirty IIRC as opposed to five on the Saturn V. And the Saturn V really only needed four. More engines is more things to go wrong.

I agree on the last point, I'm not sure why that makes the N-1 less upgradable though?

fasquardon

 

[Michel Van]

on Payloads
The soviets had Post Apollo plans for N1F like launching A Mars Rover and Mars Sample Return mission, with mastodon probes of 20 metric tons weight
Large huge Space station build from Modules of 90 metric tons mass
on long term the L3M Lunar complex using hydrogen/oxygen upper stage they would send 3 cosmonauts for 45 day mission on Lunar surface
making the Apollo landings look like weekend camping trips.

Oh hell, president Reagan would be furious, if Soviets land on Moon in 1980s
and NASA got only the Space Shuttle...

 

[Dayton Kitchens]

on Payloads
The soviets had Post Apollo plans for N1F like launching A Mars Rover and Mars Sample Return mission, with mastodon probes of 20 metric tons weight
Large huge Space station build from Modules of 90 metric tons mass
on long term the L3M Lunar complex using hydrogen/oxygen upper stage they would send 3 cosmonauts for 45 day mission on Lunar surface
making the Apollo landings look like weekend camping trips.

Oh hell, president Reagan would be furious, if Soviets land on Moon in 1980s
and NASA got only the Space Shuttle...

According to Carl Sagan's official biography, Mikhail Gorbachev was interested in a joint manned mission to Mars with the U.S. in the late 1980s and started to propose it to Reagan during a summit meeting. Reagan was warm to the idea until Gorbachev mentioned Carl Sagan being a big supporter of it.

Reagan instantly cooled to the idea as Carl Sagan and his wife had three times refused invitations to dine with the Reagans at the White House.

 

[Dathi THorfinnsson]

The huge number of first stage engines. Thirty IIRC as opposed to five on the Saturn V. And the Saturn V really only needed four. More engines is more things to go wrong.

The number of engines is only a problem if all are required to work. If the N-1 had a better system (more sophisticated electronics than were available in the USSR at the time) to allow and compensate for single engine-outs, the number of engines could actually be a benefit (redundancy) rather than a drawback.

 

[Dayton Kitchens]

The number of engines is only a problem if all are required to work. If the N-1 had a better system (more sophisticated electronics than were available in the USSR at the time) to allow and compensate for single engine-outs, the number of engines could actually be a benefit (redundancy) rather than a drawback.

I remember. The computer shut down the engine opposite any of them malfunctioned to maintain thrust symmetry.

This had disadvantages as well though. It meant that when one engine went out another was automatically shut down. Do that too many times and you could end up without enough thrust.

On the upside two of the N-1 malfunctions proved the launch escape system worked...........

 

[fasquardon]

The number of engines is only a problem if all are required to work. If the N-1 had a better system (more sophisticated electronics than were available in the USSR at the time) to allow and compensate for single engine-outs, the number of engines could actually be a benefit (redundancy) rather than a drawback.

Or using better electronics could provide the opportunity to remove engines and simplify the plumbing... With thrust upgrades, improved engineering and better electronics, you might even be able to bring the engine total down to the 24 engines of the 1962 design.

Reagan instantly cooled to the idea as Carl Sagan and his wife had three times refused invitations to dine with the Reagans at the White House.

Hah! So Carl Sagan may have stopped men from reaching Mars (yet).

fasquardon

 

[e of pi]

Mostly I was looking at costs in the event of 100% first stage recovery since it would give the more expensive but longer lasting RD-170 an advantage.

Re-usability is certainly nice, but "how" is the big question you run right back when you just completely assume it. There's a lot of ways to do it, many feasible at least for lower stages in the 60s and 70s, but it's another modification beyond the base N1.

On a slightly different topic, do people think the N-1 was significantly less upgradable than the Saturn V? I notice that discussions on continuing Saturn V use touch on all sorts of upgrades that were considered - while clearly stage stretches and adding strap-on boosters is more difficult on the N-1, were all of the other kinds of upgrades to the Saturn V similarly less practical to apply to the N-1? And if the N-1 is just a beast to upgrade right across the board, what made it so?

There's a few different ways to upgrade a rocket, but N-1 is limited on most of the standard ones. Stretching has already been discussed, and without that simple thrust improvements only offer gravity loss reduction instead of allowing a higher gross liftoff mass. Adding strap-on boosters is the second, and N-1's geometry makes that a little complex, as does its horizontal processing. The third big one is improved stages substituting into an existing vehicle, like Titan replacing Transtage with Centaur. The different diameters of the front and end of every stage on the N1 adds complexity to designing new stages to fit into the stack, and again the horizontal processing strikes. A fourth big one is cost reductions, like the reduced complexity of the J-2S compared to J-2--a change which eliminated a variety of subsidiary systems on the launcher--or changing production processes to minimize cost. N-1's launch site assembly meant it was going to be a bit of a pain to assemble no matter what, and the 30 engines leaves only so much room to improve and remove complexity without dramatic overhaul of the thrust structures.

In short, the N-1 really is a lot harder to uprate than the Saturn V.

 

[Dayton Kitchens]

Or using better electronics could provide the opportunity to remove engines and simplify the plumbing... With thrust upgrades, improved engineering and better electronics, you might even be able to bring the engine total down to the 24 engines of the 1962 design.



Hah! So Carl Sagan may have stopped men from reaching Mars (yet).

fasquardon

Or Reagan did. Depending on how you looked at it.

Sagan reportedly felt he couldn't be in Reagan's presence without voicing his disapproval of Reagans nuclear weapons policies yet also felt it would be impolite to insult Reagan at a White House dinner Sagan and his wife had been invited to.