Thanks Dwayne. One of Aerojet’s heartbreaking dead ends, along with NERVA and the AJ-260. Remarkable stuff.

Thanks for resurrecting this interesting bit of rocketry.

The M-1combustion chamber was tested on 28July1966 and generated 955,315 pounds of thrust for 3 seconds. This is the highest thrust achieved to date by a single hydrolox combustion chamber.

I did not know that the M-1 existed. One day I was doing research in the NASA HQ history archives on the F-1 engine. I pulled out a file drawer and there was a thick file on the M-1. It included photos of test stands, hardware, and illustrations (which are included in this article). It also included some technical reports, and an overall summary report.

One thing that really intrigued me was the fact that even though the program was canceled in early 1965, testing continued into 1966. I did not find any clear answers as to why that happened, but my guess is that the money was already allocated and NASA saw some value in getting the test data.

That, and my guess is that Aerojet wanted to run a few tests on that combustion chamber with the truncated nozzle after spending years developing the M-1 engine. I would. Nothing like lighting off a really big rocket engine on a test stand. Next best thing to launching it.

A combination of NASA money and Aerojet IRAD funds (which likely were mostly reimbursed to Aerojet by NASA) probably paid for those test runs.

That test happened about 15 miles from where I'm presently sitting.

I think that the image used as the opener for this article is a color painting, possibly in the lobby of Aerojet Rocketdyne HQ. However, I have not found it in color. If anybody has that color image, I would appreciate knowing. I would love to swap it out for the opener of this article.

It appears in this video:
https://www.youtube.com/wat...

Dwayne,

Thanks for all the articles on NASA’s moon missions and
plans. Love reading them.

On a completely different subject

I was watching a DVD collection I have on all of the
activities documented on the Apollo 15 mission using film (still and moving). I
saw a short but kind of violent upwards gaseous venting about the LEM, in the
blackness of space) during the lowering of the LRV, right at the beginning.
Didn’t something go wrong with the steering on the front end of that first LRV?
Could this venting have been part of the problem?

https://uploads.disquscdn.c...

Thank you Dwayne. Maybe you can clear up some confusion I have over the thrust of the F-1 vs. the M-1.
It is my understanding that the F-1 generated 1,522,000 lbf, thus with 5 burning generated over 7.5 million pounds of thrust for the Saturn V. What you have shown here is one M-1 generating 1.5 million pounds of thrust - same as the F-1. Am I mixing up units or something as they appear to have the same thrust.
Thanks in advance.

F-1 was kerosene and LOX.

M-1 was suppose to be LH2 and LOX.
The Saturn V used 5 F-1 in kerosene in first stage and 5 J-2 LH2&LOX in it's second stage:
https://en.wikipedia.org/wi...

It doesn't much sense using LH2 in first stage- even if you strap giant solid boosters to it.

Hydrolox is cleaner.

Really, humanity needs SLS propellants in Muskian Starships…I think a scaled up Saturn V-B design with an Atlas type thrust ring of M-1s would make for a fine wet stage workshop.

Here is why folks need to look at hydrogen again.
It is getting easier to come by:

https://phys.org/news/2023-...
https://phys.org/news/2022-...

More importantly—there is now an alloy that gets tougher as it gets colder:
https://phys.org/news/2022-...

Yes hydrogen takes up a lot of space—and you need metals to resist cold.

What do you need to put at least some big industry in space? A lot of floorspace that can resist the cold of deep space.

So, an M-1 with engines that can slide off Atlas style allow the rocket to BE the payload.

Bezos! Make this happen.

Wrong again. A. wet stage workshops are not needed. B. hydrogen makes for expensive rockets, and bad choice for booster stages. C. Atlas style boosters are a waste and obsolete technology.

You can't say SLS's solid boosters are clean.
In terms splitting water with less energy- that could
useful in terms making rocket fuel from water on the Moon.
Using LH2/LOX rockets work good for second stage and are good for first stage rockets with regards to Moon and Mars, as there very little gravity loss involved. But with Earth, you have start the launch phase with lots acceleration.

One could use LH2/LOX on first stage if you have some sort of assisted launch- like Mag Lev track.
But you might also use strap on rockets which are not solid rockets. Or NASA was planning replacing solid boosters for Shuttle with flyback liquid engine booster, but it didn't happen. Or like Delta-IV Heavy with it's two side booster which were LH2/LOX engines rather than using solids.
Or a problem with Shuttle flyback, is you didn't have falcon 9 showing how to actually make them reusable.

So could make something like Falcon Heavy, though bigger, and use LH2/LOX rather than Kerosene.
Anyhow, I thought Blue Origin, New Glenn changed plans and is going to use Liquid Methane and LOX on first stage and LH2/LOX on the second stage- which I think is good idea.

Close to what I have been thinking about! A big outer first stage ring of engines and smaller inner second stage ring and a single center third stage engine on a Chrysler SERV type vehicle. The super heavy has 33 engines and 17 million pounds of thrust using raptors so a larger version of the SERV, using a 2 million pound thrust range hydrogen engine is interesting to think about. With an outer ring of 8 and an inner ring of 4 smaller approximately half a million pound thrust engines and a last single central engine that would all add up to around 19 or 20 million pounds of thrust.

The concept being that the structure containing propellants is a large part of the actual payload so only the engines are returned for reuse, this would make for a huge wet workshop.

Climate Change is driving a big push for green hydrogen and ammonia to replace fossil fuels and Space Solar power is the ultimate solution. Studies have shown that building the Space Solar components in factories on the Moon, while a much larger initial investment and more time consuming, end up costing far less than launching directly from Earth. These giant wet workshop crew compartments would be the critical piece of hardware in creating a cislunar infrastructure.

We could have a sit-down with Bezos. As soon as he gets his problems with unions figured out. His workers started to unionize after he thanked them for making his billionaut suborbital tourist ride possible.

They are unanimous in their hate for me--and I welcome their hatred.

And no more cowboy hats.

No, because the hydrogen comes from reformation of methane, it is not cleaner.

There is no point to wet workshops. A tank has one job, and it makes up so much of the dry mass of a stage it must be optimized for that task, this means it is not a good hab. The best way to make a hab now known is and non-metallic inflatable.

It isn’t always going to come from wells….we are getting closer to getting it from sea water

And when we get there, the problem will be the concentrated brine to disperse. Nothing is for free, and most thing we might do are not worth doing -- especially what is done to soothe the moral vanity of the Greens.

I tried to post a link to an article about getting hydrogen from oil well byproducts but it died in the spam filter. It is on New Atlas and titled, "Light powered catalyst makes profitable hydrogen from stinky waste".

We will always make plastics and lesser products from petroleum and the energy industry knows this but they want to continue to make huge profits burning it.

They are unanimous in their hate for me--and I welcome their hatred.

Before building big industries in space, you need to prove manufacturing in space can make money, which means starting at a small scale. Should that be doable, wet workshops from hydrogen sustainer stages still won’t get you much floor space - far better to send up panels that can be densely packed and then assembled in space, or invest in vehicles such as Archinaut and SpiderFab - or better yet, both. Then we aren’t limited to the high cost, refurbishment time, limited volumes and limited launch rate of something like the SLS.

Chicken and egg again.
The reason I still want government and old space in the lead is as a spearhead.

Here is my scenario:

SLS evolves to side mount as Space Force funds a Buran type Shuttle 2. This has jets and is just another airplane…allowing flights to airports to show the flag even without actually having a spaceflight.

SLS launches station modules. Buran 2 sends 15-20 tons of raw goods up (leaving SLS cores occasionally as wet stations) and the orbiter flies down with 20 tons of processed goods…not just a sample from ISS…that has failed to inspire.

You have to have a big, CES level of goods to get real investment from industry.

As it is, they think they can sit back and just let Elon do everything. The problem is…he does too much…and is too easily distracted…and Bezos is too much of a tightwad.

We have to act as if these two men don’t exist…and demonstrate to everyone else in industry—in a big way mind you—that space manufacturing can really deliver the goods….then the floodgates open.

Your scenario is unrealistic. The USSF is not going to do that. If anything, they’ll buy spaceplanes from the multiple companies currently working on them, or fund something like Skylon, not an SLS-launched Buran imitation. There will likely never be a station launched by the SLS, nor will core stages become wet workshops. Full stop.

Industry is not going to be thrilled with a launch system that costs billions in transport, is already fully booked with a tiny number of government flights, cannot fly on a regular schedule, and is costly to improve. There are a growing number of companies investing money in space manufacturing - I know of at least half a dozen - so no one is waiting on Musk to do everything. I see no evidence to back your assertion that he is easily distracted, and hit pieces are not persuasive.

No, I don’t think ‘we’ do. Inexpensive transport to and from space - which the SLS by definition can never manage - is paramount to enabling the further industrialization of space. So is the construction of space stations by commercial entities with far lower prices, and numerous technical and operational improvements, over the ISS, which is woefully inadequate to meet the needs of firms looking to build things in space. It’s usable, but only just. There are at least five companies in the process of designing space stations, not including partners and subcontractors.

Legacy companies are too lethargic and expensive to serve as a spearhead, and the government has better roles for it than trying to mimic the Soviet Union or the Communist Party of China. Writing and enforcing appropriate regulation, funding basic research, providing law enforcement and judicial services once sufficient numbers of people are living in space; these are all suitable and desirable. Living in the 1960s is not.

ISS is still larger than these private stations…and floorspace there isn’t going to produce in bulk…you have to make industry sit up and take notice. Maybe a law requiring a dollar invested in space for every dollar invested in X.

publiusr, think about the cost of transport to and from a factory. High transport costs (along with an environment not intended for manufacturing, which I’ve already agreed the ISS is a poor fit for) mean that you can only afford to make very expensive products, which means a higher upfront cost. I do not understand why you insist on bulk manufacturing from the start, yet turn around and argue for transport architectures that make that impossible.

As it happens, look up the company Gravitics. They are working on Starmax modules that, in a handful of launches, can offer far more space than the ISS can ever dream of. Vast is similarly designing a large station, and one that can provide artificial gravity.

A law requiring a dollar invested in space? How authoritarian of you. Join us in the 21st Century, publiusr. Quite a bit has happened since 1975, and you’re missing out by remaining nostalgic for the past.

I’m talking about human nature, Nate.

Unlike Starship, which is going to be finicky for awhile…a Buran type Shuttle 2 with J79s for not just self ferry…but show off at air shows…fly-overs…that’s going to be a hit even when it isn’t strapped to Energia 2. It can have some of those products in.

I see Shuttle 2 as a salemen. Now, if at some point in time you can make Energia 2 and RLV…fine.

Musk doesn’t like wings—I don’t like trying to fly a bunch of resonating tankage….leave that as a wet workshop…no landing legs, no heat-shield. Stage and a half. I’m agnostic on the strap-one.

You said start small with manufacturing. ISS already did that. Larry DeLucas tried—in vain mind you—to get people to notice his work—-but how many air-shows have the crowds in their thrall?

I’m trying to get you guys to look over the fence on this.

Again—-you have to act like Bezos and Musk don’t exist…because you don’t know what tomorrow will bring…so we should support institutions and not individuals. A Buran type Shuttle 2 on an SLS mod will keep the powers that be happy…the blue suits will have something with wings to fly besides Branson’s contraption…but the important thing is having “mass quantities” of goods to shove into the faces of the Wall Streeters. Those damn suits are like dogs that won’t eat a pill until you shove their face into the bowl.

No, there is no justification for a "Buran type Shuttle 2" on anything. And a Shuttle flying around solo is idiotic. Again, no need for a one of a kind PR vehicle.

Also, the blue suits are not in charge anymore and those bluesuits in the past that were in charge didn't have an affinity for wings on a spacecraft. This is reality, not somebody's incorrect perception

There is no reason to "act like Bezos and Musk don’t exist". SpaceX stands on its own. Musk has been doing less and less with the company and it has a competent president. SpaceX can exist without Musk.

I hope so...I understand space investment is downward
https://spacenews.com/space...

I’ve tried responding to this twice and my comments won’t post, so I’ll say this:

Think about incentives, and think about what can be affordably produced in space at various costs per pound. A cost of $12,000/lb means a product should be multiple times more pricy so a company can stay in business; dropping to $500/lb, or $100/lb, means far more business cases can close. Think about development cycles, and what it means to wait years in between payload deliveries, which if the SLS is the launch vehicle of choice, are unavoidable even with increased flight rates. Until you can answer those challenges, this discussion will just go in circles.

I'm talking capability. You want folks who build rockets to be as healthy and as well supported as anyone who builds payloads---redundancy. Right now the next SLS cores are nearing finish. Not rebuilding---reloading.

A system that can only launch every couple of years, at billions a pop, is not much capability viewed in isolation, and viewed against competition, is not much redundancy either. Again, think about what can be affordably produced in space given the cost of launch. If you want mass manufacturing, it's absolutely imperative that you have both very low costs, and frequent flights, with plenty of downmass. Realistically - so no Buran clones or Energia IIs - can you envision the SLS managing any of those? I cannot.

You know what an egg tooth is right?

It is an expendable evolutionary asset that plays a part in breaking through.

What has support across multiple states? SLS. That's your egg tooth.
I can see it---and maybe Buran2--getting Space Solar Power started.

Now what is Starship? That's the chick's wings.

It is going to be awhile before that chick flies right? But you need that egg tooth NOW.

Musk doesn't like SPS...but if we can get Solar Power launches under the belt---and he gets Starship as dialed in as he does Falcon....I see Starship doing the lions share of powersat lofting once you have institutional inertia behind it.

Right now, we have divided gov't...so neither side can do everything they want to do. If they could, the fiscal hawks of the right would have killed SLS---and those on the left may have done so as well--but since they hate Elon---they may love SLS as a union rocket.

All politics are local--so SLS has broad support.

It is one of those few things that can find greater votes ACROSS party lines than any other concept can find WITHIN party lines. The right wants to kill Medicare. They can't. The left wants to extend it---they can't. But like F-35....which will cost us 1.5 trillion total--SLS has reach across the board.

Folks here have gone hoarse screaming for SLS to die---and what has that gotten you?

Nothing.

So take a cue from Shakespeare and understand THE PLAY IS THE THING.

The right knows folks are fed up with forever wars--so there will be no B-17 Keynesian build up that can grow us out of this. The folks on the left have to sell being Green without looking like fools in going for gas stoves.

But space based solar power can get aerospace into the lucrative energy sector--so that's growth for them. The defense firms should jump at that. The left will have their green agenda in part---and right now Green Banks could fund that where they don't fund drilling---and an Elon-free union rocket will sell them. The fiscal hawks and the fringe on the other side won't stop this bi-partisan movement of the margins.

This buys time for Musk's system to grow.

Starship comes to the fore--and is what truly brings launch costs down for space solar power.----but the vested interests have their legacy---some photo-ops with SLS, or whatever.

I am talking politics here...there are certain things you have to do---egos that need stroking....it is all part of a dance, see?

To compete successfully against ground-based power sources, space solar needs very cheap transport to space. Without that, and possibly without in-space manufacturing, it's a nonstarter. Launching with the SLS means orders-of-magnitude higher costs, and many years of waiting, versus going with commercial launch.

Space has never once been important enough to the electorate for it to be a major campaign issue. Not since the dawn of the space age. Ask the average man on the street, and he won't know or care about Artemis. The SLS matters to a handful of people in Congress, some space fans, and the corporations building it - I don't see how it can ever engender a fraction of the support and excitement Starship can. If you want widespread public excitement, the public has to be able to go.

I think your salient assumption is that the government will remain at the forefront of spaceflight for many years to come. I believe that the government will be involved, certainly, but it will not be dominant. Congress and the general population simply do not care enough. They'll get what they want, and they'll become irrelevant in the process. You certainly won't get what you want, supporting the program of record.

Also: for once, can you answer questions directly instead of dodging them and effectively repeating yourself?

Got it! Thank you.

"Had it been built, the M-1 would have been a monster, the most powerful rocket engine ever developed. It would have fueled the upper stages and possibly even the first stage of rockets to follow the Saturn V."

The future is the full-flow hydrogen oxygen rocket engine, in this thrust range, powering VTVL reusable two-stage rockets like the Starship. All the major players will be building their own or licensed versions of these "Monster" Launch Vehicles.

Great article, thank you!

They are unanimous in their hate for me--and I welcome their hatred.

Considering SpaceX's drive to increase Raptor's thrust, prioritizing it well above specific impulse, and the endless headaches with SLS's hydrogen systems, with the vehicle only getting off the ground due to a crew being sent out to the pad to make the fixes necessary to get it fully fueled...I really don't see much of a future for hydrolox booster engines of any combustion cycle. And even the upper stage benefits hugely from the denser, moderately-cryogenic liquid methane.

We spent half a century obsessing over hydrogen's specific impulse. Today, the orbital launch market has been dominated and vastly expanded by a launch system that burns kerosene, from a company that has never used hydrogen and has no plans to start doing so.

Hydrogen burns cooler…less trouble with burn throughs.

The Energia RD-0120s had smooth development compared to hydrocarbon engines.

RD-0120 development is irrelevant to this conversation.

No, most players don't need "monster" launch vehicles. And "licensing" is not possible.
Also, cost matters over thrust and specific impulse and this drives rockets away from hydrogen, especially for booster stages. Hydrogen might have a place in a integrated fluid vehicle such as ULA proposes but the same can likely be done with methane.

SpaceX seems to think they need a monster. Licensing is possible. Thrust is what matters if you want to go to space and getting there is what costs. Methane actually is the worst of both kerosene and hydrogen as it is not very dense, much like hydrogen, but not nearly as powerful. The main problem with methane is that when you burn it you are producing carbon and that is not going to continue.

They are unanimous in their hate for me--and I welcome their hatred.

It looks that way because you only considered one factor ISP. The insulation and lack of density of Hydrogen cut into the performance of the rocket. ISP is a bit like fuel efficiency in and of itself sounds great but you have to look at the whole system. A small car might have the best fuel efficiency but be the worse choice for transporting large numbers of people(many trips needed) or an heavy trailer.

Anyway Kerosene while dense cokes the engine and does not store well in space. You can clean out the engine but it is better not to gunk it up in the first place if your rocket is meant to be reusable. Methane burns clean. Kerosene also tends to separate in orbit. It can last hours but not a good choice of propellant if you need days or weeks in space. Methane is a better choice than either Kerosene(Separation) or Hydrogen(Boil off/Metal embrittlement) when it comes to long term storage in space.

Basically because Methane and Oxygen are mild Cryogens that are liquids at the same temperature an Lox\Methane rocket can have a better Dry weight than an Lox\Loh rocket. In addition it is denser than Hydrogen again improving dry weight. The net effect is that a Lox\Methane rocket can do 99% of what Lo\LOH can do for less.

The endless replay of "lack of density" does not seem to have been a problem for various launch vehicles from going to the Moon and launching big birds into GEO for half a century. It is not a car. And while 99% sounds good, the Isp of Methane is a little over 360. For Hydrogen it is well over 400.

And the central problem is decarbonizing space launch.

They are unanimous in their hate for me--and I welcome their hatred.

Wrong again. None of those vehicles used hydrogen for the first stage/booster. One all hydrogen vehicle was developed this century and it was heidously expensive even though it was designed with CAIV. One of the vehicles you refer to is converting its first stage from kerosene to methane.

None of what I said was inaccurate. What is "heidously"?

They are unanimous in their hate for me--and I welcome their hatred.

In this case VERY and the Delta V heavy is very expensive compared to Atlas or Falcon 9 for lifting payloads.

Delta IV wasn’t really fat enough for hydrogen—you need at least SLS size for that—but while D-IV wasn’t big enough for hydrogen—it was unwieldy compared to Atlas V. Take a D-IV size rocket…but fill it with Atlas’s kerosene in it—and that’s Falcon.

It is not like paying more for a pound of sugar at the store. Some people want it to be, but that is not reality. Hydrogen is not egregiously more expensive to use than methane and the higher Isp and no carbon make it the winner. If Elon said he was switching to hydrogen tomorrow all his fans here would cheer and act like they never said anything bad about it.
They are unanimous in their hate for me--and I welcome their hatred.

No, it much more expensive and paying more for sugar per pound is a waste of money. You have to be careful when you optimize for just one variable in an complex problem(Space Travel or Global Warming). In this case ISP. ISP isn't everything and Hydrogen production can produce more carbon than Methane for two reasons. The source of Hydrogen on earth is usually oil because it takes less energy to break an Carbon Hydrogen bond than a Oxygen Hydrogen bond. The source of Methane is usually a well and can be made carbon neutral by turning existing CO2 in the air into Methane.

So there isn't much of a green excuse here. And spaceflight is no where near the biggest source of CO2 production. How many electric cars could be subsidized for the cost of 1 SLS rocket and reduce overall CO2 production that way. Trust me thousands of gas burning cars off the road would reduce C02 emission much more than trying to reduce it for spaceflight.

This is why reducing the cost of spaceflight matters. Lowering costs means we can do the same or more for less money. You can then apply that savings to other things like global warming, healthcare, or even something spaceflight related.

Yes, you would like it to be about sugar, just like I mentioned, but it's not. The "green excuse" comes into play when Space Solar Power is agreed upon by all the major governments as the solution to climate change and that all launches of Super Heavy Lift Vehicles, and there will be tens of thousands, will burn hydrogen. And that hydrogen will not release carbon (green hydrogen). Everything else in your reply was just a distraction.

They are unanimous in their hate for me--and I welcome their hatred.

"but it is not going to happen." <-- For rational economic actors, it has already happened.

Because they were willing to spend inordinate amounts of time/money and accept far narrower margin, meaning higher risk, for the sake of that higher Isp. Now a more intelligent choice is being made, optimizing overall system performance, not mindlessly pursuing Isp alone.

"And the central problem is decarbonizing space launch." <-- An idiocy. What is vital is making it inexpensive and reliable enough to be ubiquitous, a packet service.

SpaceX needs a monster because they have goals that nobody else has.
Methane is the best of kerosene and hydrogen. It is has higher ISP than kerosene and higher density than hydrogen. It is like LOX and doesn't need insulation like hydrogen.
Hydrogen is made from methane.