# Speedrun to the moon in one lifetime?

Imagine you have a large population of adolescent humans (as large as you need) on a completely uncultivated Earth, initially containing no artificial structures whatsoever, only natural resources. Suppose, however, that these people possess the same amount of technical knowledge as we currently do today, and that they are completely united (no infighting, politics, etc.) in their singular goal of reaching the moon during their lifetime.

Starting with modern-day knowledge but no starting infrastructure, can a population of humans put a person on the moon within a human lifetime?

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– L.Dutch
Commented Oct 6, 2020 at 2:43
• Volume of moon's orbit/Volume of average human means that I could probably do it with around 10^30 humans. Commented Oct 7, 2020 at 3:10
• 1. What exactly is "put a person on the moon?" A) Dead body since launch, B) dead body after spacecraft crashes on the moon, C) person gets there and can do few steps but is left on the moon, D) person gets there and back again. The first one is much simpler than the last. 2. While I am not going to write an answer how to do it or research if it is really possible, consider that in a lifetime of a person we went from no airplanes to a man walking on the moon. With imperfect people fighting many wars and having to invent everything needed. I guess food is going to screw you, though. Commented Oct 7, 2020 at 7:06
• @ZizyArcher you have different categories, of course: organic goo%, recognizable corpse%, alive on impact%, alive after impact%, there and back%, no permanent injury%... Commented Oct 7, 2020 at 11:11
• Sounds like someone has been playing Factorio :) Commented Oct 7, 2020 at 19:47

# Impossible

This is an extension of, or complement to, L.Dutch's answer, which was first. I upvoted it. So should you.

I'm fond of reminding people that 99.99% of the technology we enjoy today was invented in the last 150 years. Based on that observation, one could jump to the conclusion that what you're asking is possible, perhaps even plausible.

But that would be a lie.

150 years ago was 1870. Take just a moment to consider just how much infrastructure existed world-wide in 1870.

Assumption #1: A "single lifetime" is an 85-year period, from the day our teens are theoretically useful 15-year-olds to their deaths at an average age of 100.

Assumption #2: We'll assume that the available humans are capable of working and thinking like 30-year-olds from age 15 all the way to age 100. This ain't true. Humans on average don't really become industrially productive until around age 25 (physical and mental maturity) and start winding down physically at 45 and mentally at age 65 (these are rough and optimistic averages, of course). But even assuming you could get all 85 years out of your team — my answer still stands.

## Infrastructure is, quite simply, the problem

Building any (and ONLY) one of the millions (not thousands, not hundreds-of-thousands, but millions) of components needed to successfully launch a crewed spacecraft equal only to Apollo 11 requires an industrial and technological pyramid of interconnected disciplines so vast that it's simply impossible for teenagers, no matter how smart or how unified, to complete in a single lifetime starting with (did I understand this correctly?) absolutely nothing.

Assumption #3: When you mean "no infrastructure," I assume you mean absolutely nothing. There are no utilities, no factories, no houses, no farms, no ditches... nothing. If I'm wrong with this supposition then you need to produce a SUBSTANTIAL AND HIGHLY DETAILED starting point for your humans.

Let's pick just one item: a single LS7400 NAND microchip, invented in 1966.1 That one object, the LS7400 NAND chip, required:

• A silicon foundry capable of at least 100µ geometries.
• A packaging and assembly facility.
• A testing facility.

Those three facilities, which can be combined under one somewhat large roof, require...

• Electron beams
• Photo lithography
• Robotics (crude compared to today, but nonetheless...)
• Computers
• Software

And a bazillion other things. I know you're not an electrical engineer, but that industrial and technology tree just became ENORMOUS... and we're only at the first level of very basic dependencies. Let's jump near the bottom of that tree (not the bottom, just near the bottom)...

• Electricity
• Water
• Sewage
• Vacuum tech
• Plastics
• Metallurgy
• Concrete
• Woodcraft...

All of which requires agriculture, mining, and logging, which requires more machinery, more tools, more factories, more industry.... Somewhere in that massive tree of dependencies are the industries that create hammers, screwdrivers, forklifts, cranes, furnaces (very precise furnaces, not just smelting).

If I tried to make this list comprehensive, I would literally (LITERALLY) write a book-sized treatise and the one and only thing I would have done is list the dependencies... I'd have actually explained nothing. A book.

• Tools
• Machines
• Buildings
• Animal husbandry (and you'll have to catch and train the horses... a LOT of them...)

And, of course, the millions (yes, millions!) of teenagers would need...

• Food
• Clothing
• Entertainment
• Health care
• Homes (with household goods...)
• Government...

Assuming most of them didn't die before developing the ability to grow, package, and distribute food to so large a group. And what did we get for that? One component out of millions, an LS7400 NAND chip.

## But, let's say that our intrepid teens number in the tens of millions and are, somehow and magically, already organized into teams of tens, fifties, hundreds, and thousands, such that each group knows exactly what they need to do each step of the way. What then?

Assumption #4: They're humans, meaning their memories aren't perfect.

Which is important because without infrastructure, there would be no books, no guides, nothing but their memories to guide them until they could create books...

I can't take it anymore. Just the task of developing the infrastructure from scratch needed to record the knowledge they have so they don't forget it might take more than a lifetime. You can't have just one copy of anything, so now you're inventing movable type, printing, binding, paper, glue, thread, machines, tools....

I'm sorry, and I beg you to forgive me, but you're asking a question from an entirely untrained perspective.

What you're suggesting is impossible.

1I designed 74BCT and 74ABT BiCMOS chips, which you'll find briefly described in that Wiki document, and the more complex MultiByte family of components based on that technology created by Signetics Corp, and then Philips Semiconductors. Geez, that was a long time ago. Feels like yesterday.

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– L.Dutch
Commented Oct 7, 2020 at 2:51

I don't think it's feasible.

First of all, for anything they need, they might know what they need to build, but they have no way to reach the place where the raw materials are located. E.g.

Jim: "cool, we need gasoline to supply our trucks to transport materials."

Pedro: "To make gasoline we need oil"

Alexa: "Where can we find oil, and how do we reach it with our bare feet?"

Then, more importantly, they have no way to communicate and coordinate efforts. Don't forget that the race to the Moon in the 60's was a coordinated effort of an entire country, with hundreds of thousands of people working together according to a plan, backed up by industries and an government already up to speed. There wasn't a rocket expert wannabe in each and every town in the US trying the feat on their own.

Without effective communication you cannot coordinate the effort. You will need more than a lifetime.

• Comments are not for extended discussion; this conversation has been moved to chat.
– L.Dutch
Commented Oct 5, 2020 at 18:52

It can't be done.

There's a famous phrase in project management, "Nine women cannot make a baby in one month." This is one of those cases where you just can't parallelize enough. The project management term you should be interested in is called the "critical path." This is the longest sequence of activities that have to be done in serial because one depends on the other.

For example, aluminum is a pretty critical component of spacecraft. Now for spacecraft, you don't just need aluminum. You need good aluminum. The trace materials must be immaculately controlled. You aren't looking for some backyard smelter. You're looking for a properly constructed industrial aluminum smelter, using the Hall-Héroult process. These factories are beasts. It is simply not reasonable to produce aluminum on a small scale. The US as a whole sports 14 of them, according to Wikipedia.

So how fast can you make one of these? This article from Iceland suggests that one might take 7 years to construct. Now these efforts are being run by project managers who are trained to build these things as efficiently as possible. There might be some potential to speed it up because it's of utmost importance, but we have to consider the supply lines. That was 7 year in a modern world with access to all of modern shipping, modern building materials, and modern construction equipment. All of these things need to happen before the smelter can be constructed.

And one of the major things that is needed is a steel industry. Not only do we need construction equipment, but simply put Aluminum needs power, and the electrical industry needs steel. The trashy steel from the 17th century isn't going to be sufficient to make electrical generators that can power the gigawatts needed to run an aluminum smelter. Yes, it takes gigawatts before you have a aluminum production scale that is really worth talking about (the Wöhler mechanism for extraction, done before full scale production in the 20th century was so painstaking that aluminum produced by it cost nearly twice as much as gold!). You need real generators which are going to withstand the load of powering these furnaces. And really, the only way to get that good of steel is to start with crummy steel, which is used to construct a crummy eletrical power plant, which is then used to produce a better steel, and a better power plant.

If I handwave a bit (because I'm having trouble finding resources), lets say the good steel plant and the good electrical plant take 7 years each, just like the aluminum plant. Now we're sitting at 21 years.

Now, how long is a lifetime? I think 60 years is pretty reasonable. I mean, you're being put on a strange planet without any medical facilities, so practically speaking it should be a whole lot shorter. But some of them might live to be 60. So we've used up 1/3 of our human lifetime on just constructing a steel plant, electrical plant, and aluminum plant.

Now lets talk raw materials. You say the planet has natural resources. Unless nature has kindly tied them up in small crates of pre-refined materials, you're going to have to mine them. And you goign to have to do it starting with nothing. Not even pick axes. Needless to say, our ability to produce resources is going to be limited in this situation.

How limited? Well, much of mining before the industrial era is going to rely on beasts of burden. We won't have those, because we don't have time to domesticate any species. So we're going to have to use human power. Literally we will be dependent on slaves until we can get to mechanical power of the steam era.

So how long does that take? It's goign to take a long time. We're going to be working with clay, wood, and rock for quite a while before we acquire enough metal to enter, say, the bronze era.

And all of those were assuming that we had time to do these things. Maintenance of the H. sapiens body calls for calories. While we can initially support the populace on canabalism, taking advantage of your "as many humans as you want" rule, we're going to run out of them anyways. Human meat does spoil... Anyways, this process can take generations before we have enough understanding of the local climate.

So I chewed up 20ish years of the timeline with just a few technical structures that need to be built. 1/3 of the time has to be spent building just that one line of infrastructure. No computers, no hydraulics, no nothing. And, practically speaking, it is almost certain that your planet, no matter how driven, will not have the resources available in the modern world in just a single generation. So you should multiply that out.

Then, you have to raise the question of acquiring resources. This would easily take generations.

Then you have the pesky issue of survival. Unless your humans are waking up from stasis on a regular basis, your workforce is going to need to survive.

I would say no due to issues of food production.

The problem is not clearing enough land or having manpower.

The real problem would be in breeding good enough strains of crops and livestock to feed a large population, the situation would be different if they had seeds and draft animals with them but without that I would claim it is extremly unlikely.

• Good point, making significant progress in domestication is really hard to do in a single human’s lifetime. However, OP stated that there is no limit on the number of humans. Even if a hunter&gatherer society can only produce enough food surplus to allow 1% of their population to spend time on more important tasks it would still be enough. Commented Oct 4, 2020 at 16:25
• @Michael Alternative reading: no limit on the number of humans means an unbounded food supply. I just need to find a book on How to Serve Man. Commented Oct 4, 2020 at 16:54
• @CortAmmon The supply may be unbounded, but it will be scattered over an unbounded region. You don't have the infrastructure to bring the produced food to the places were it is needed. Commented Oct 4, 2020 at 19:09
• @Abigail "If brute force doesn't work, you're not using enough!" Commented Oct 4, 2020 at 19:12
• @Abigail well by that reasoning we can do it, just use enough population to fill a sherical volume up to the moons orbit, but I do not know if creating a flesh planet counts, there will be no surviviours for sure Commented Oct 4, 2020 at 21:19

No, even if you have a magic Wikipedia type thing for "Starting with modern-day knowledge... " rather than relying on people knowing stuff. (And most modern knowledge is, in fact, simply knowing how to use existing infrastructure.)

I see lots of other good answers, but it all really comes down to the basics: Food, shelter, water.

Most of your initial population are going to die in less than a year. They will either starve, have an accident, get a disease, get poisoned, or one of a bunch of other dangers will kill them. Without infrastructure a skinned knee will kill a bunch of people. There will not be any time to build up infrastructure, they will simply spend all of their time trying to stay alive, most will fail.

You said adolescents, too. Even if everyone has genius level intellect, and no mental issues, there is going to be zero experience at any of the things they "know" or read about, experience counts for a lot, especially when it involves physical interacting with stuff. e.g. You can read all you want about digging, but until you do it, you won't really understand some parts of it.

I will ignore the level of mind control required to make a group of people get along perfectly, and work toward a goal without friction. That alone might mitigate some of the problems with getting everyone food and shelter, lots of them will still die. Sanitation is no joke either, nor obtaining potable water for more than a dozen or so people.

No, even if a bunch of things go right, it would take generations, infrastructure is important. Possibly the most important thing.

NASA sent people to the Moon using different bases (launch was in Cape Canaveral, command in Houston). Each base had an enormous amount of infrastructure already in place.

Your people will have to build mines, labs, refineries, regular roads, rail roads etc. Even with all insfrastructure in place, that takes time. If you think it's slow because of governments, remember that in the US the bulk (if not all) of the infrastructure construction and maintenance work is done by efficiency oriented private contractors.

ll all your people have are rocks and sticks, then they have to go through the stone, bronze and iron age in a rush just to be able to start getting into the modern era. Which leads to the most pressing problem for them:

these people possess the same amount of technical knowledge as we currently do today

A lot of the knowledge which bridged the gap between the bronze and iron ages was lost. We are not sure today how the ancients made Damascus steel (and other forms of steel), and we have a good idea of how romans made cement but we can't know for sure. Lots of people even force themselves into thinking the pyramids of Giza are the work of aliens because caucasians nowadays can't figure how those stone blocks were stacked.

Your people will have to spend multiple lifetimes figuring out how to build ancient stuff before modern knowledge becomes useful again. By then, that modern knowledge might already be lost and will have to be rediscovered too.

• I intended their “modern knowledge” to be cumulative. Not only do they possess knowledge of modern technology, but everything before it as well - without background knowledge, much modern scientific “knowledge” wouldn’t be comprehensible anyways. Commented Oct 4, 2020 at 5:45
• "we have a good idea of how romans made cement" - and, bad news, it relies on volcanic ash. Unless there's been a recent eruption in the vicinity - or if the recipe turns out wrong - they'll even struggle to build a VAB. Commented Oct 4, 2020 at 8:06
• @JohnDvorak: Oh, the eruption doesn't have to be "recent". There are millions and millions of tons of pozzolanic earth lying around the Mediterranean. The problem is that hauling it over long distances is not economical. (The Romans did it, sometimes, when they felt it was worthwhile; for example, they exported some tens of thousands of tons of it from Italy to Palestine to build the breakwaters of port of Caesarea Maritima.) Commented Oct 4, 2020 at 12:38
• we might not know how ancient people did it, but we know to make steel. surely the steps to go from nothing to making steel, however long it takes, is known Commented Oct 5, 2020 at 1:26
• @shieldgenerator7 How long it takes is actually important, but one of the primary issues is that, unlike developing technology, implementing technology requires a bunch of laborers. To brainstorm and come up with new ideas, you can use the old many people supporting a few thinkers paradigm. But when you already know the tech, and just need to build it, all the people are going to be needed to build the stuff, and that leaves precious little extra for farming and otherwise keeping folks alive. Commented Oct 6, 2020 at 1:15

You could do it instantly (although you might think my answer is a bit cheap):

"Imagine you have a large population of adolescent humans (as large as you need) "

I will take enough adolescent humans that they cover the entire Earth and then pile up on top of eachother all the way to the moon.

Have a nice day.

• Is a planet (or star) which mostly consists of humans and has a radius all the way to the moon even possible? Commented Oct 5, 2020 at 10:38
• This answer would be better supported if you could provide an approximate count of adolescents this would require, accounting for mass compaction of the lower layers. Commented Oct 5, 2020 at 18:46
• – Mark
Commented Oct 6, 2020 at 2:31
• @DanielB A spherical shell between the earth and the moon is about 2.4e26 cubic meters. With each human occupying about 0.06 cubic meters, you'd need about 3.6e27 humans to fill that space, nearly a billion billion times the current population of the planet. This assumes no compaction due to pressure, so the actual figure will be somewhat higher (although humans are mostly water, so I 'd expect them to be relatively incompressible, but that's just a guess). Commented Oct 6, 2020 at 14:50
• @NuclearWang I think far before you reach that point, the moon's orbit will degrade enough for a "soviet russia" solution ("... the moon reaches you") to the OP's question. Commented Oct 6, 2020 at 20:56

### Yes - because you've cherry picked people that better than anyone on Earth currently.

I'll get into what I mean by cherry picking soon, but first Some simplifying assumptions I've made:

• You did say put a man on the moon in their lifetime. You didnt say it had to be one of the original settlers walking on the moon. Cherry-picking the best of Earth they'll live to their 90s on average +- 10yrs std dev, but 0.3% percent will live to they're 120, and the person they live to see put on the moon will be one of their grandchildren.
• Because we've cherry picked the best education, they're smarter earlier than average humans. A decent distribution of teens would be ideal, but the youngest should be perhaps 12. 120 - 12. That's just over 108 years to do it.
• You didn't say bring them back. It's probably also possible to bring them back within 100 years of dev, but having them die on the moon is much easier!

"they are completely united (no infighting, politics, etc.)".

Currently the people on Earth have divisions. These divisions have some advantages and many disadvantages. By uniting them - they can cherry-pick the best of each society on Earth and ignore all the negatives. No single society of humans on Earth will be as good as these people. They pick the best behaviours so as a consequence they live longer, they're smarter (they've picked the best education), stronger (they've picked the best exercise regime), etc because they're United. Uniting makes us better than just coordinated, it pools wisdom.

Also, complete unity implies they have communicated this goal within the population and gathered agreement. This implies some form of either communication or at least pre-planning in order to learn this fact.

While that communication is happening - you need to basically sort every required technology by its dependencies. This is a mammoth task. As an example of one tiny part of the tech tree:

• You need aluminium production for the craft.
• Aluminium production needs steel, power and Bauxite mining.
• Power needs copper, magnets, coal (or wood or wind or flowing water) and steel.
• Bauxite mining needs steel.
• Steel needs iron and coal.
• efficient iron and coal extraction needs steel and power
• inefficient iron and coal extraction needs geological mapping and rock or copper tools
• magnets and copper extraction needs steel and power.

Sorting just this tiny part of the tech tree puts the following work at the leaf nodes:

• Geological surveying (find magnetite, copper, iron, bauxite, and coal).
• Remember you have current knowledge. So you know what geological features to look for at the surface to predict near-surface ore deposits.
• Make simple stone tools for extraction of those resources when found.
• Remember you have current knowledge. You know good designs for an axe, a shovel, etc.

Once stone tools are made. Start extracting wood. Once copper is found and stone tools are made start extracting copper. Once copper is extracted start making copper tools. etc.

There are many things current knowledge gives that don't need "stuff" to be of benefit. You know manual handling so you wont put your backs out. You know first aid. You know good hygiene practices so you wont get as sick (even if you don't have soap yet - you know to boil something to disinfect it). You know to have sewage drain away from your drinking water. All these things that slowed the human race down wont slow you down.

There are many other tech trees that need to be worked on. You need tools to plot where the moon will be (telescopes and measuring equipment). You need cryogenic fuels, you need heat pumps to make the fuels cryogenic, you need space suits, you need buttons and electronics, you need batteries, you need fuel cells, there's probably another 50 tech trees, all having their own leaf nodes.

There's also survival tasks that need doing. Food, shelter, etc. With exceptional pre-planning (and/or good luck) this can start in a comfortable climate with ample food and clean water. You could also distribute groups of people based on natural resources to minimise the amount of farming needed.

With current knowledge you can take some shortcuts or take the easiest of several paths if needed - we may not need oil to get to the moon for example: Hydrogen fuel can come from electrolysis, plastics can come from processing plant matter.

• This answer would very greatly benefit from adding a proposed timeline. First you make pottery and wooden beams and such and this takes x time. Then you find a copper deposit and smelt the copper, and this takes y time. Then you find a way to draw the copper into wires and this takes z time. Then you find a way to coat the copper wires in an insulator coating and this takes t time. So it take x + y + z + t time to have electrical coils. Commented Oct 5, 2020 at 7:24
• The problem is the time needed. Simply bootstrapping your coal and steel industries (there's a feedback cycle between them: better coal mining lets you produce more steel, which lets you make bigger mining apparatus, which lets you...) is likely to take more time than you've got. Remember, the starting point for your coal mine is a person breaking off chunks of coal with a rock, and it's going to take months to upgrade that rock to a metal shovel.
– Mark
Commented Oct 6, 2020 at 2:29
• There are 7.6 billion people on the Earth right now and a whole 0 of them are 120 years old. There have been an estimated 108 billion people on the Earth EVER, and there is exactly 1 recorded case of someone who lived 120 years. No amount of cherry-picking is going to give you anything other than microscopic odds of getting a even single person to live to 120. Commented Oct 6, 2020 at 5:58
• @AlexanderJ93 all people recorded to have become more than 100 stopped being productive workers before their 70th birthday. Commented Oct 7, 2020 at 22:55

Impossible to sent by building an Apollo equivalent project in that timeframe. I agree with the tons of written stuff here explain why not. It is more possible to build a true monster-gigantic classic catapult at the highest mountain or by using round-spin force from a large set of air balloons to launch one human encapsulated at a protective shell than anything else.

While I'm inclined to agree with many of the responses, they omit one factor that may be important - the question doesn't ask us to re-create the Apollo mission, but rather to place one person on the Moon. There's no requirement for safety or repeatability, and so it would be possible to achieve the goal with a craft far more primitive than 20th-century space vehicles. If we were to make do with solid fuel rockets, manual piloting, breathing air out of sack, and a 1% success rate then the task would be very much easier. The specific impulse of a gunpowder rocket is about 80s, vs 360s for a liquid hydrogen rocket. The Apollo mission used a 2800-tonne rocket to transport 41 tonnes to lunar orbit. Assuming we discard everything that we don't absolutely need, we might need to take 100kg to the lunar surface. I confess that estimating the required size of a gunpowder rocket puts me slightly out of my depth but a guess of 20-40 tonnes seems plausible, and perhaps achievable if we were to circumvent any problem that we couldn't solve (e.g. high quality steel alloys can't realistically be created within a lifetime, so do without them).

• "There's no requirement for safety or repeatability" Or indeed that they should be alive. Commented Oct 5, 2020 at 16:44
• Estimating the size of a gunpowder rocket is well within my capabilities, and the answer is that given a suitable quantity of unobtanium, putting 100kg on a Lunar impact trajectory will require roughly 125,000 metric tons of gunpowder. If you want your astronaut to survive landing on the Moon, that goes up to 2.6 million metric tons. When dealing with the rocket equation, low specific impulse is not your friend.
– Mark
Commented Oct 6, 2020 at 2:41
• You're simplifying the top 0.01% of the industry/technology pyramid and assuming that's all it needs to solve the problem. A comment made my @Mark for Ash's answer makes an awe-inspiring point: The first coal must be picked up off the ground or dug out of it with your hands. So would the first iron. It would take months to get to a decent pick and shovel and years (if not decades) to get to rudimentary steam engines because it takes the re-application of technology over and over to build ever more capable tools. Simplifying the top 0.01% doesn't reduce the time for the bottom 99.99%.
– JBH
Commented Oct 7, 2020 at 2:35

# Not in one lifetime, no

As others explained, this is impossible in one lifetime. There is simply too much dependence on technology that takes large amounts of time to step through even if you know what you're doing.

But what if we were to relax the "single lifetime" constraint and consider an inter-generational Moon% speedrun? How fast can you go?

## Progression

Assuming that the knowledge is properly preserved via hundreds of copies of a set of encyclopedias that these teens begin with and that the goal and unity is somehow preserved across generations...

To make this easier, we'll assume these adolescents have no natural predators and that they begin in an area with rich resources so there's no initial risk of starvation. We'll also assume instant skill and knowledge in all tasks from age 15 onward.

### Starting Point - Stone Age

You start with stone and wood tools. You can make fire. You make fur clothing in the first year and stick with fur for as long as possible. Stone age technology is basically there for free. Simple enough.

### Food Production

The first and largest hurdle to overcome is food production. Under a hunter-gatherer system, you simply won't have the surplus energy to do anything but survive. Domestication and breeding potentially requires hundreds of generations, and is too slow for a speedrun. Using beasts of burden for agricultural labor is therefore likely out of the question.

Your people are going to have to be primarily vegetarians living on low effort crops (e.g. zucchini, grapes) and mushrooms. Any meat in their diet is going to have to come from hunting, which should be limited to opportunistic hunting and absolute nutritional necessity. Grapes in particular are important, as you need something that ferments easily since you don't have refrigeration and can't necessarily count on boiling your water all the time.

This strategy doesn't free up very many people, but since everyone is united in the goal of going to the moon and you don't have to invest any time into research, this will still be enough to buy that small fraction of people time to work toward better infrastructure and technology. It will have to do until you can make machinery to automate food production.

Optimistically, you can graduate from hunter-gatherer to crude agriculture in a generation or two.

### Iron Age

You first need to make clay to create furnaces. Invest time into mining coal, as it is going to be more efficient for smelting than wood.

Skip the bronze age. There's nothing stopping you from making rudimentary steel at this point. Steel gives access to tools like saws, knives, and hammers, allowing for better wood tools and wood shelter, making farming a bit more efficient and freeing up labor. It also feeds into itself for increasingly better ability to smelt iron.

All of this mining and smelting is labor intensive and time consuming, but you don't have to waste time making weapons to kill each other with, so that helps considerably.

### Beginnings of Automation

With steel, you have all the tools you need to continue along the tech tree. You start with windmills and waterwheels to free up a few folks on the farm. You move on to making gears and high precision machinery. Rubber comes next, and soon you have bicycles as your main mode of transportation in less time than it would have taken to domesticate horses. There's a ton of other miscellaneous tech in this era I'm glazing over, but there aren't really any roadblocks at this point. The only limiting factor is time and inordinate amounts of manual labor.

### Steam and Electricity

Steam power, combustion engines, and electricity all move toward getting people off the farms and into making things for the rocket. Electricity enables radio communication and telephones. You begin making rudimentary robotics and the machines that make the machines that make the machines that make the machines that make the electronic circuits for the rocket.

Once you have industrial automation, your moon landing is only a lifetime away.

So my guess: it takes 10-20 generations (i.e. about 200-400 years) under ideal conditions. Under realistic conditions, you might beat history by 1000 years. Maybe.

Consider using robots instead if you wish to pursue this setting seriously. Robots could actually do all of this within a human lifetime since they don't need to eat and can craft things at a high precision without tools.

• Making steel is not that hard plenty of people today know how to di it even using primitive methods. Plus building blast furnaces is about knowledge technologically it is not that hard so you may be able to skip many steps in development.
– John
Commented Oct 8, 2020 at 1:49
• Bronze is really hard to make, mostly because one of the components is rarer than gold. skip straight from copper to iron, iron is extremely abundant.
– John
Commented Oct 8, 2020 at 14:49
• @John What you're saying about bronze is not true. Bronze is Copper and Tin, which are 70 and 2 ppm of the earth's crust, respectively. Gold makes up only 0.005 ppm. If you're concerned about rarity, you can easily use brass instead of bronze since zinc is more common than copper at 75 ppm. Historians consider both alloys roughly interchangeable. Commented Oct 8, 2020 at 15:21
• Yeah I was off about the rarity, but it is still to rare to rely on large scale. Zinc is not a solution because refining zinc is very difficult, to the point that you basically have to have large scale steel production first. Honestly there is no reason not to start smelting iron immediately it is not terribly difficult if you know how to do it.
– John
Commented Oct 8, 2020 at 15:32

Yes, possibly, if you don’t drop all of your people off at the same time.

Let’s consider one person’s lifetime to be equal to 100 hundred years as a rough approximation. Now that we a solid timeframe we can break our task down into two phases:

1. Get to a 1869 tech level
2. Condense the time to go from a 1869 tech level to a 1969 tech level

For phase (1) it is helpful to look at situations where roughly 1869 tech had to be replicated, having very little of the tech readily available. Fortunately, we have just such a situation to use as an example: the development of the United States, and the western expansion of the US. It’s not a perfect match, but it may be close enough for us to get some numbers out of it.

It took nearly 400 years to go from discovery to 1869 tech, of course some of that time was spent developing the tech...

Below is a supply list of things (other than food) and their weight for the Oregon trail for a family of four:

• Bedroll 15
• Blacksmithing Tools 200
• Books 75
• Medicine 10
• Cast Iron Stove 300
• Chair 20
• Cookware & Eating Utensils 75
• Granny’s Clock 15
• Gun Making Tools 200
• Keepsakes 40
• Mirror 15
• Gunpowder 80
• Tent & Gear 150
• Tools 50
• Toys 15

This was used to established new towns, and should be a fair approximation of what is needed for a roughly 1850 tech level, provided the people know what to do.

So, how do we go from naked people to blacksmithing and gun making tools? We build it up of course. Start with 15 people able to kill rabbits with rocks and make either flint knifes or bows (preferably both). Give them two weeks, by which time they should be able to feed themselves and maybe 1 other person. Drop off another 15 basket weavers, they are going to be slower than the bowers. Wait a month, introduce 15 new hunters and 15 potters. Keep on introducing new people and base technologies at a steady rate.

You should be looking to double your population at each step, with prior step able to feed and integrate the next. They shouldn’t all have the same time interval (you’ll need to introduce farmers, they’ll need at least a year, possibly two to make the step from hunter gather, to create and store enough food for the step).

You want to get to about a 100,000 people. Once you’ve reached that point, you should have a good spread of farmers and machinist, tools, tailors and everything else you need. Then it’s simply a matter of growing your population and building the tools to make the tools.

I think it’s doable, but you need specifically trained people and probably 20 years to do it (unless you can simply drop them off at the right time all at once).

Sure

The moon is 384,000 km away.

A human has about 50 kg of water.

A sphere of radius 400,000 km (rounded up, accounts for radius of Earth, and maybe you want to be on the dark side) has a volume of $$\frac{4}{3}\pi r^3$$ has a volume of 267946666666666666666666666.66667 cubic meters, which is under 10^27 tonnes of water.

20 humans weigh more than a tonne. So 2 * 10^28 humans will form a sphere large enough to swallow the moon.

Now at that mass, water being incompressible is an approximation. That is 2% of the mass of the sun, so the result will be a brown dwarf or something more exotic (a lot of oxygen!)

But at that size, the moon will be well within the Roche limit of the post-planet, and will disintegrate; if man can't go to the moon, the moon will come to the many thousand km deep ocean of dead corpses.

Barring something like that, you run into the problem that the basis of industrial society -- domesticated crops and livestock -- takes thousands of years to tech up. You can't fast forward it that much, because it takes generations of work. Such high-density crops and lifestock are in turn needed to maintain the population densities required for myriads of other technological advancements on the way up to a moon shot.

A large percents of technology is actually building the tools needed to build better tools. Building each iteration of tooling takes a huge amount of effort. We amortize this over huge numbers of people and years.

Knowing what to do each step (and note, no human alive knows all of the steps, or even knows all who would know all of the steps) would save some effort, but you still need human hands to manipulate materials, purify better ones, and iterate an ungodly number of times.

Without sufficient population density (afforded by the earliest steps), time spent carrying each technological improvement to all of the people who need it explodes.

Technology might look like magic and tricks. But much of it is a ridiculous numbers of layers of extremely specialized expertise and technology woven together into a world-wrapping supply chain.

They would have to start by making houses by each other, forming a little kingdom like place but not really one yet. They would soon be able to make fire and bows and arrows to start hunting all withing the first few days.

After that they might start professions, so that way others can work on more things like getting to the moon. The first thing that they will need is iron to make steel if they want to make this rocket.

They might be able to make the fuel after a couple of years, but they will still need things to make the rocket itself out of.

They will start to mine for iron to make the rocket out of. But they will need a whole lot of it.

By chance, they could get some from asteroids that crash around their pretty big kingdom. That could be their first way of getting iron. But they would need that iron to help them get more iron.

With help from the asteroids that they may find, they should be able to get all of the iron that is needed to make one rocket after a decade or two.

The next step will be to make the rocket. They would need to spend a long time just to get the rocket together, and they would have to spend so much time doing the math if they want to rocket to work.

To get a human onto the moon they would also need to make them a space suit which would take some time.

So they would have to start spending a long time to make steel after they get all of the iron that they need. But they should be able to get enough steel but it would be near the end of the lifetime.

They would have to then put the rocket fuel into the rocket and that will be hard to do, and they will have to work on the button that will launch it.

So they're also put some food into the part of the rocket that the person will be staying in. But I'd say that at the end of the lifetime they should have made the rocket and gotten the person in their. I'd say that the lifetime may end while the rocket is in space, but if they do it fast enough, they might be able to go to the moon and back before the lifetime ends.

The lack of infrastructure would condemn your attempt.

And no, "infrastructure" does not just mean the obvious constructed stuff like roads, waterworks, etc. Cultivated, gene-specialized-by-very-long-selective-breeding plants. Remember that corn, wheat, tomatoes, potatoes, even apples DO NOT EXIST in a "completely uncultivated Earth" ALL of these are the result of many,many,many generations of selective breeding by farmers, over thousands of years. The original apple is a sour berry the size of your fingernail. The original corn looks like a stalk of grass!

Ditto for domesticated animals. You will have no horses, no chickens, no cows. Their wild equivalents will be there, but they will not have the placid, easily tameable nature of the domesticated version, even if raised in captivity from birth. (ask any cassowary farmer how tame they are, compared to turkeys)

Your people will get hungry for at least the first several dozen years, and won't be eating or farming comfortably for the first several hundred years.

The high-yield corn and wheat that allows a very small number of farmers to feed a huge number of other people is just as much a product of technology as a steam-powered locomotive!

And simply having the knowledge of corn does not enable you to plant it, just as knowing how to build a steam engine does not give a naked man with no tools, the ability to build it.

If you lower the planet's gravity then the task becomes much easier.

For example titan has a mass of 0.0225 Earths and surface gravity of 0.138g. This gives it an escape velocity of 2.64 km/sec and an orbital velocity of 1.87km/sec. This means that the WW2 era V2 rocket would be an orbital class rocket and you could send any WW2 era plane into orbit with a solid rocket motor strapped to the back.

Given that WW2 technology is difficult to achieve there are other ways of getting to orbit.

1. You could do it with large fireworks that require 14th century Japanese technology (Paper and gunpowder.)

2. You could make a rocket out of cast iron that runs on Hydrogen Peroxide and Ethanol. This is achievable by an Iron age civilisation.

You would have to deal with humans living on a 0.138g world. It might be fine. We know that 1g is good and 0g is bad for humans, but we have no data on what happens to humans between 1g and 0g so 0.138g might be enough gravity to have healthy humans. If you want titan to be a reasonable temperature then just move Saturn closer to the sun.

• Titan is not orbiting Jupiter. This would invert the challenge, getting to Earth from the Moon. But WW2 era rockets are not much easier to achieve than Satun Vs, see the other answers. Commented Oct 6, 2020 at 8:25