There are a lot of good comments here. So let's assume unlimited money starting in 1960. Here is what I think we would have. 1. Super efficient plasma propulsion. There are already a lot of prototypes of this already today, but they haven't been heavily invested in. The tech for it is well within our capabilities, and with this propulsion travel times in the inner solar system at least become reasonable. Ie, weeks between earth and its neighbors rather than months. 2. Reliable reusable heavy lift rockets. Starship is amazing, however if there has been real investment we could've had something similar decades ago. 3. Separate launch and travel vehicles. The process of getting off of earth is very different from the process of flying in space. Vehicles today need to be able to do both, which is inefficient. Having dedicated space vehicles, built in space, optimized exclusively for space travel, would be a game changer. 4. Lots of space stations. You launch from earth to a station, then either stay there or transfer to a ship going elsewhere in space. 5. Asteroid mining. Moon bases/mining. Colonies on Mars and maybe Venus (floating cities in the air). Maybe some outposts in the asteroid belt. 6. Likely manned expeditions to the outer solar system and possibly very small scale research outposts there. However it is unlikely we would have the tech to make travel times there reasonable.

If we can include unlimited political capital, we'd be using fission powered drives in space.

> unlimited political capital unlimited money can pay the bribes for this!

Uhhh excuse you. They are called tips/gratuity

It's called lobbying. And yes, it's bribery. 

How can you use fission for propulsion? Don't you need to be pushing against something physical to accelerate? (Possibly a stupid question)

Fission is the energy source. You use that energy to speed up your propellant. A high-thrust option is to heat hydrogen and let it expand in a rocket nozzle. Hydrogen, being the lightest atom, achieves the highest velocities at a given temperature. Ion thrusters provide a lower thrust but they are more propellant-efficient. They need a lot of power.

There have been a few different attempts at doing this since 1970. Three that I know. One was by the British

You do indeed need something to push against, in conventional rockets that is the fuel they bring with them. The hotter they can get that fuel the faster it'll go the other way, the more you push yourself the way you want to go. How you heat up said fuel isn't really important, in convention rocket engines that is a chemical reaction, how exactly one uses a fission engine I'm not sure, but it will need a kind of fuel to shoot backwards. It might be ions like in an electric rocket engine, or a superheated gas, or the fission products itself.

>how exactly one uses a fission engine I'm not sure, You run liquid hydrogen through a stack of uranium. Uranium heats the liquid hydrogen, it rapidly changes into a gas - expanding much as it would if it were combusted with liquid oxygen - and is expelled out through the nozzle. From there, the operation is identical to a traditional chemical rocket: bells are sized and shaped to match the expansion of the gas for the environment it is in, some of the expanding gas is shunted off to run the pumps, to keep the liquid hydrogen flowing into the reactor, fuel in the "combustion" chamber and nozzle preheats the liquid fuel on it's way to the chamber, etc. Basically, it operates exactly the same, except you get to use "all fuel", since you don't need to carry liquid oxygen to induce the conversation from a liquid to a gas. Or, more nuanced: you ditch the excess weight of having a second tank, the weight of the insulation you need between the liquid hydrogen and liquid oxygen tanks (they are both very cold, but still nowhere near each other in temperature), and you can use all the volume in the rock for storing liquid hydrogen (which is lighter than liquid oxygen both as a molecule). It's basically as efficient as you can make a "chemical" rocket (even though it's not a chemical reaction anymore, just a physical one). After that, you're looking at plasma rockets, which don't involve any gases going through a phase change, or similar, and are just using electromagnetism to accelerate a plasma instead.

>except you get to use "all fuel" to clarify though that’s not what makes it more efficient right? Mass out the back is what makes things go so fuel + oxidizer or all-fuel both deliver the same efficiency at the same velocity. The advantage of nuclear is that the fuel can get way way way hotter than burning and the mass-out-the-back goes faster.

This made me think about it a little and go dig up one of my old textbooks. Basically, you're correct that temperature *does* plays a role, but it is *not* the primary role. From *Basic Astronautics*; by Ordway III, Gardner, and Sharpe Jr; 1962; Chapter 10.5, Advanced Propulsion Systems, Nuclear Propulsion; [Pg.421](https://i.imgur.com/GO48Uz9.jpeg): >Comparison of the every available by chemical combustion and fission processes reveals that the fission process is potentially capable of providing approximately a million times more energy on a unit-fuel weight basis. Taking into account the fact that less than 1 percent of the uranium fuel will be fissioned in present [1950s-1960s] rocket engine reactors and considering the thermal efficiency of the two propulsion systems, we are still impressed by the tremendous energy available in the nuclear fission process. >One major problem confronting the designer of a nuclear propulsion system is finding an efficient method of transferring the tremendous heat available in the nuclear reactor to a working fluid or propellant. **The specific impulse obtainable is proportional to the square root of the chamber temperature and is inversely proportional to the square root of the man molecular weight of the exhaust products. From this we see that by selecting a low molecular weight propellant the exhaust velocity is only restricted by the structural limitation of the chamber.** Since we are dealing with a heat transfer process and not a combustion process, it is not necessary to use a chemically reactive propellant as the working fluid. Some liquid propellants that are considered as working fluids are hydrogen, ammonia, ethyl alcohol, and octane. Emphasis mine. Mass out the back is important. But so is dry mass of the empty rocket. And you can get that mass out the back faster not only because you can get it hotter, but by keeping the mass itself lighter. Or by selecting a mass that can conduct heat better (so that it will 'expand faster', and achieve a greater acceleration out through the nozzle). Basically, lots of the factors, but the math more strongly favors lighter molecular weights of fuel over thermal conductivity of the fuel (needed to take advantage of the high chamber temperature)

I wish people would stop being so scared of nuclear power. The Russians with Chernobyl ruined it for everyone.

We certainly didn't help ourselves on that front with Three Mile Island.

Three Mile Island doesn't even deserve to be mentioned in the same *paragraph* as Chernobyl. One resulted in a *massive* exclusion zone that will be unsafe for permanent human settlement for centuries, with certain areas still radioactive enough to kill you from radiation poisoning from acute exposure; and the other *may* have slightly raised the rates for certain types of cancers in a very localized population. If you want a comparison, Fukushima is at least better, in the sense it, too, has resulted in an exclusion zone. But the released radioactive materials still aren't comparable to Chernobyl (chronic exposure in some areas *will* make you sick, acute exposure will not)

You basically described the progression of For All Mankind on Apple TV+. Which is a great show by the way.

The first two seasons are 100% possible now with unliminited NASA budgets. Moon bases! Really cool shuttles! Maybe even a rotating space hotel!

I really enjoyed the first 2 seasons, but the show has really gone downhill. At this point, it's just a bunch of really dramatic characters being incredibly unprofessional, with space as a backdrop.

Great list! A few points you missed: * Space based nuclear power; we really only have reached using RTGs, which are essentially just nuclear batteries. It's also quite plausible we'd advance to fusion power with asteroid mining too, as honestly that really is just a money problem to scale up and finish it at this point with recent developments. * With the above, you enable electromagnetic gamma deflection shielding, by making an EM field around the ship. Whilst this uses a TON of power, if we've got fusion and water asteroids, you suddenly have an incredibly viable way to have longterm spaceflight. * Recursive Processing. In space, you could have a system capable of mining asteroids, refining ores, fabricating parts, and repeating, with iterative AI chips for advanced automation. Whilst this absolutely leads to a grey goo scenario, the fact is that we COULD build it with the tech we have now.

I'm really curious how heat dissipation for space-based nuclear power would work. That would require a hell of a heatsink/radiator.

If you're using nuclear to heat water to generate steam to turn a turbine, then yeah. If you're using something like RECS or another PIDEC variant that uses _emitted photons_, then there's a lot less waste heat to deal with.

Heat is the form the energy output itself takes. You would ideally store it in a battery, not radiate it. Batteries are already experiencing significant investment and improvement. With unlimited money, think how much better they would be.

Even the best heat engines are only around 60% efficient at converting heat into electricity, which is why nuclear power plants need big cooling towers with lots of water to get rid of the 40% that is waste heat. In space you don't have a convenient ocean or river to tap into so you need radiators to get rid of the waste heat, but radiators only become efficient at high temperatures. But that lowers the efficiency, because if the difference in temperature between the reactor core and the radiator is small because the radiator is similarly hot then you cant convert the heat to electricity as efficiently.

What’s a grey goo scenario ?

Self-replicating robots that replicates without limits. As in, "ooooh, look at that walking pile of resources, nomnomnom"... A grey goo scenario is when self-replicating machines "eats" everything. Planets, people, stars etc. The usage of the name "grey goo" is a reference to self-replicating nano-machines, where the machines are so small you cannot see them individually, but with enough of them it will look like a grey goo.

Runaway nanotech. Nanotech which is corrupted / designed to create more nanotech out of whatever it touches. We are not even at the point of making nano bots in research labs. Forget us getting close to making a self powered one, with enough computational power to follow complex instructions anytime within the next couple of decades at least. Not to mention manipulators which can move individual molecules to create things in such bots.

We have MEMS though... micro machines... https://en.wikipedia.org/wiki/MEMS

We kind of do though - Life. Essentially, life is a form of self-replicating nanotechnology. DNA serves as the set of instructions for creating and maintaining organisms, and through processes like cell division, these instructions are used to create more life. When a cell divides, it replicates its DNA, and this replication process is remarkably efficient and accurate, given the complexity involved. The cell then uses various molecular machines (proteins and enzymes) to build new cells. These molecular machines operate at a nanoscale, manipulating individual molecules to carry out the instructions encoded in the DNA. From a universal perspective, this self-replicating nature of life can be seen as life transforming available matter into more life, much like the grey goo scenario. If you think about it, the biosphere on Earth has, over billions of years, transformed a significant portion of the planet’s matter into living organisms, constantly converting raw materials into more life. Humans are a product of life, and we've reached a point where we're capable of leaving this planet and utilizing resources from other planets. Grey goo is real, and it's us.

> grey goo https://science.howstuffworks.com/gray-goo.htm

Self replicating nano machines convert everything they come into contact with into more of themselves. Earth or any other celestial body becomes a blob of Grey goo, humans right along with it.

EM deflection shielding - is that a thing? I’m struggling (with my basic physics understanding) to grasp how this could deflect gamma radiation.

The Earth's EM field, which is an example of EM deflection shielding.

That does cosmic rays, not gamma rays. Hence my question. Gamma rays aren’t typically affected by EM fields.

Not really a thing with current physics understanding.

Thanks for the sanity check. That was my understanding also, but I’m not really super current on it.

With infinite power and space mass harvesting maybe you could make a field of highly charged particles? That would potentially stop gamma radiation? But its a stretch. The way way way simpler system is to just coat the outside of your ship in rocks/ice... or have tanks/bags on the outside to fill up with mass.

> Recursive Processing. In space, you could have a system capable of mining asteroids, refining ores, fabricating parts, and repeating, with iterative AI chips for advanced automation. Whilst this absolutely leads to a grey goo scenario, the fact is that we COULD build it with the tech we have now. I don't see how we have the technology for "recursive AI chips for advanced automation" right now. AI right now is pretty good at writing shitty novels and making up historical facts, but that's about it. For proper output for consumption, whether literary or art, it still needs human editors.

> AI right now is pretty good at writing shitty novels and making up historical facts, but that's about it. _Generative_ AI is only good at those things -- but that's what you're associating with "AI" because that's what's in the news. AI for more-targeted purposes is already adopted in many areas with very good results; it has limitations, like any tech, but things like "teach a machine some patterns and let it extrapolate and make inferences" is a lot more capable than ChatGPT. What we don't have is advanced _general-purpose_ AI, but things like self-driving cars have significant AI components that are pretty damned good already and getting better all the time. Special-purpose AI that lets a remote human operator be more efficient (by doing more things at once or by automating the routine) is established and working well.

An AI that can do gray goo(even figuratively) is THE holy grail of AI, also known as AGI. Even some of us humans doubt we may not be general intelligence after all. No way unlimited budget alone can solve it.

Your third bullet is a bit incoherent, but if you think that today we could build a system capable of mining asteroids, refining them, AND fabricating parts…you’re way, way, way off base.

If we can start space mining it would enable us to start manufacturing away from Earth which could massively reduce travel time For example in theory if we could set up shop on Venus then we can travel from venus to Mercury instead of having to travel from Earth to mercury which is a much larger distance. Same rule applies to other planets

Your going to want to stay out of the undesirable places with large Gravity Wells, like Planets. Unless you have some sort of Anti-Gravity Drive that is...

Yea Lagrange points would be much better I'd assume.

A lot of the advancements that we have today are real because we have very powerful computers for the M&S, as well as control.

>Asteroid mining. Moon bases/mining. Even with unlimited money, asteroid and moon mining has to make economic sense. Maybe, if we had been investing in space technology at a much higher rate since the 60s, it would make economic sense to mine asteroids and the Moon. Maybe not. But unless we can mine asteroids or the Moon more cheaply than we can mine the Earth for the same material, it's not going to happen.

The point isn't to drop it back to earth. The point is to use it in orbit.

Might make sense for rare metals obtained from asteroids. Slap a few drogue chutes and a tracker on a hunk of gold, bolt it to a heat shield and drop it into a shallow-ish bit of ocean. Send a team down with floats to bring it up to the surface. If you could manage that with a cubic meter of gold, that's a *lot* of electronics that just got a lot cheaper.

Sure. But the bulk of the volume would be metals suited to construction. Costs a lot of money to send a hull worth of iron or aluminum into orbit. With enough scale it can be much cheaper to just yoink it from an asteroid. Then you build the structure of your spacecraft in orbit and send the electronics up.

Asteroid mining is never about bringing stuff back home, it’s about using the stuff in space - metals for in-orbit vehicle construction, ice for water, oxygen and fuel etc. So the unit cost has to be cheaper than mining on earth + getting the stuff to space, which is quite conceivable with sufficient scale.

> Asteroid mining is never about bringing stuff back home Oh, I wouldn't say never. Once an operation can get going in orbit, it has the potential to process such gobsmackingly huge amounts of material that even just a few percent could handle almost all the bulk raw material needs back down on Earth. Then we could stop digging up our own crust and we could set about reclaiming all these swaths of strip-mined terrain.

Also, you can get as big a mining operation in space as you want, but processing is going to be an issue. Beneficiation can be a complicated chemical process. Check out the path that gold or copper or aluminium takes from the mine to the refined material, used in industry. On earth, this is done at scale in large industrial plants - and developing technology to do something similar in zero-g is actually the biggest challenge for utilizing asteroid minerals in space.

The moon seems like the perfect way point for this. Set up the industrial plants on the Moon and keep the side products there for potential future use

I mean, unlimited money for effectively unlimited resources seems like a good deal to me

The real savings will be in getting it off the moon rather than off the earth. Anything we mine in the moon or an asteroid will save tons of fuel by not having to come from the earths surface.

There is a huge amount of valuable minerals locked up in asteroids and the moon. The primary obstacle is launch costs. In this hypothetical scenario, with massive investments into the space program, launch costs could easily come down enough to make this viable. On top of that, production of space ships and stations in space itself has big cost savings over developing on earth. The issue is the up front cost of setting up the infrastructure, but again the hypothetical proposed is what would happen if there was unlimited money. Space based construction would most efficiently leverage space based resources.

Building large space structures would be cheaper with materials mined from asteroids. Lifting material out of the Earth's gravity well is expensive.

Yea, any kind of mining off of earth would mean manufacturing as well.

How would the economics of space minting scale? Say we found an asteroid comprised of 90% gold. We extract it because it makes financial sense. But when we bring back hundreds of kilos worth of gold back, would that plummet the value because of how plentiful it will suddenly become? Or any precious metal for that matter?

There is no point in doing that though, its still cheaper to mine gold on earth and if you have unlimited funds well... then you don't need to do it for money, do you. The point of mining in space is to gain resources to use in space more easily than it is by yeeting it off Earth Sure, cost is one thing but if we ignore the costs space mining is still better because its faster, more efficient and most importantly: SAFER than sending resources from earth

The big appeal to space mining is in space manufacturing, not dropping raw materials back on earth. [https://en.wikipedia.org/wiki/Space\_manufacturing](https://en.wikipedia.org/wiki/Space_manufacturing) Most obvious use-case is mass producing satellites in space instead of having to launch them from Earth.

I think Gold is a bit of an exception because it has a lot of value as a tech metal (I don't know the actual scientific term.) 

Literally sounds like the plot to For All Mankind

Right! William Anders from Apollo dying at 90, while doing a stunt flight, seemed totally like something Ed Baldwin would do. Loved that show.

> Reliable reusable heavy lift rockets. Starship is amazing, however if there has been real investment we could've had something similar decades ago. Not sure how you would've made a vertical landing rocket without 2010 or later CPUs and software.

That's not the only way to make reusable vehicles; it's the way that makes the most sense given the tech we have, but other types of recovery systems for lift rockets have been designed and were scrapped for cost (as in, never built and tested/refined)

You overestimate the computational requirements. The math isn't that hard, what's expensive is finding out enough about the physical system to model it accurately. For a reusable booster, there are also a lot of design constraints that make the booster more expensive/able to carry less payload, which are wasteful if you don't succeed.

Skyhook! https://www.youtube.com/watch?v=dqwpQarrDwk

I think the point of the question was what we could do with today's technology and lots of money. You're imagining technology we don't have.

We could build something like Project Orion. That was a proposal for spaceships built to move using the energy of nuclear weapons to push the craft further. It was projected to go 0.05c so we could make it to Alpha Centauri in about 90 years. I think it is definitely viable since this was an idea from the 60s and we have 60 years of progress since then. https://www.astronomy.com/science/humanity-may-not-need-a-warp-drive-to-go-interstellar/

We also could build a direct thrust nuclear engine. And engine capable of sending us to any object we've found orbiting the sun. Possibly even allowing us to send a probe to another star. https://en.wikipedia.org/wiki/Fission-fragment_rocket#Dusty_plasma

What the shit? This is a lightspeed engine that is very near future technology. Thats absolutely insane

We are even closer to making this work than we are to a fusion engine. I'm surprised by how few people have even heard about it.

I guess my question is... if you're going that fast over that long.. How do you maneuver if there's an inbound collision? How do you deal with microdebris? How do you slow down at your destination?

Not sure about collisions but to slow down I’d imagine you’d use RCS thrusters to flip the rocket around and fire up the engines opposite of the direction of travel.

Hmm that's true, I think I remember the ships doing this in the Expanse now that you mention it... Gives a nice visual :)

Also theres just nothing out there. The odds of you bumping into anything out there would be pretty slim.

Space scenes in movies where they have to dodge asteroids is messed with people because there's hundreds of thousands of miles between asteroids in an asteroid belt.

For avoiding catastrophic collisions, the first part is detection. We already have tech for that around earth. Improvements and modifications could be made doe deep space. For actual debris deflection options include: 1) flipping around doesn’t just work to slow, it could also remove/deflect some debris or change flight trajectory enough to evade 2) explosive armor - basically a modified version of what tanks have on battlefields today. Incoming debris seen, fire something at it to knock it out of the way. This could be more like missiles, drones, or bullets than armor. 3) Shielding of some kind - sci fi of the 1960’s theorized things like an ice shield on the front, more realistically, some repairable/replaceable/unimportant area at the front of the ship that also guides most of the impact away 4) the biggest debris field/issue is around the earth itself thanks to humans, so start far enough away from earth is a good start Realistically some combo of this stuff might be needed

I've seen this before but in the context of this post it makes me think a little. A lot of sci-fi alien robot tropes make them disposable to the central intelligence. Same goes for hive minds regarding drones. They wouldn't have a problem irradiation their planet to spread to others, would they? Heck, maybe radiation doesn't hurt them. Then again aliens could be exactly like us, but the coin flip lands the other way and they actually launched Orion before realizing how bad it would be for their planet. Either way, it puts the Fermi paradox in a new perspective, doesn't it? If intelligent life is out there they could spread across the galaxy in no time at all, so why aren't they?

If you include research and a decade or so it might be [Breakthrough Starshot:](https://en.m.wikipedia.org/wiki/Breakthrough_Starshot)

Anyone failing to mention some variant of Project Orion [nuclear pulse rocket] is severely underestimating what is possible. It was doable with 1960's technology. The only hindrance is a lack of meaningful application, and political considerations for using it as earth-to-LEO launch vehicle vs assembly in orbit. Given unconstrained motivation to direct our economy towards making it real, we could build a sizable fleet of large ships capable of going a single or double-digit % speed of light. Now... can we actually create a colony ship and get a few generations of people to survive on it for the decades necessary to reach another solar system? That's a question that can't be solved with money [alone]. Similarly, the ability to acomplish something meaningful at the destination may be constrained more by knowledge and technology and psychology than resource dedication.

Why is Project Orion so low in the comments, this should be top comment. https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) They even had a prototype using chemical explosions working > **The most successful model test, in November 1959, reached roughly 100 meters in altitude with six sequenced chemical explosions.** NASA also produced a Mars mission profile for a 125 day round trip with eight astronauts, at a predicted development cost of $1.5 billion. Orion was canceled in 1964, after the United States signed the Partial Test Ban Treaty the prior year; the treaty greatly reduced political support for the project > The biggest design above is the "super" Orion design; at 8 million tons, it could easily be a city.[25] In interviews, the designers contemplated the large ship as a possible interstellar ark. **This extreme design could be built with materials and techniques that could be obtained in 1958 or were anticipated to be available shortly after.** > At 0.1c, Orion thermonuclear starships would require a flight time of at least 44 years to reach Alpha Centauri, not counting time needed to reach that speed (about 36 days at constant acceleration of 1g or 9.8 m/s2). At 0.1c, an Orion starship would require 100 years to travel 10 light years Just shows how effectively nuclear space technology has been demonized by various interest groups.

[Orion](https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)) has been the right answer for 60+ years and remains so to this day for massively jumpstarting industrial scale space and for getting large vessels and payloads around the system, not just in Earth orbit. We need low yield clean nukes in space desperately for so many reasons. I love me some [NERVA](https://en.wikipedia.org/wiki/NERVA) but Orion is good for what ails humanity.

>The only hindrance is a lack of meaningful application, and political considerations for using it as earth-to-LEO launch vehicle vs assembly in orbit. its not a political hindrance to use it for Earth to orbit it's an environmental impact question. as in do you want to set of hundreds of nukes within Earth's biosphere? the radioactive fallout would be immense, probably making all of Earth as safe as Chernobyl. the political hindrances remain on using it in space. convincing rival nations to bet their existence that your going to use thousands of nukes for purely peaceful purposes is challenging.

Well, with sufficient will ( money being an outcome of that ), there would need to be mamy more than one ship, with each ship fulfilling a specific requirement i.e. - Reusable earth to LEO launchers for "vitamins" & personnel - Aldrin Cycles to ferry personnel & materials from LEO to cislunar space - Automated & crewed mining vessels to gather & refine material from Earth Crossing Asteroids & put them onto low energy barges to ferry the to cislunar space - A Lunar L1 station to gather these resources & build components for a lunar Mass Driver. - A lunar Mass Driver with telepresence mining robots to launch more refined materials into lunar orbit - A lunar orbit shipyard & station to build all the next generation of interplanetary craft - The interplanetary craft for exploration & exploitation - A solar powered power station using lasers to accelerate sail craft - Interstellar smart dust probes propelled by the orbital lasers to explore the whole local stellar neighbourhood within a human lifetime by having the smart dust accelerated to 10% if c.

Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread: |Fewer Letters|More Letters| |-------|---------|---| |[CNC](/r/Space/comments/1drde30/stub/lavhmbj "Last usage")|Computerized Numerical Control, for precise machining or measuring| |EVA|Extra-Vehicular Activity| |[ISRU](/r/Space/comments/1drde30/stub/lavgj6j "Last usage")|[In-Situ Resource Utilization](https://en.wikipedia.org/wiki/In_situ_resource_utilization)| |[JWST](/r/Space/comments/1drde30/stub/lav9282 "Last usage")|James Webb infra-red Space Telescope| |[KSP](/r/Space/comments/1drde30/stub/laydai2 "Last usage")|*Kerbal Space Program*, the rocketry simulator| |[L1](/r/Space/comments/1drde30/stub/lauld85 "Last usage")|[Lagrange Point](https://en.wikipedia.org/wiki/Lagrangian_point) 1 of a two-body system, between the bodies| |[LEO](/r/Space/comments/1drde30/stub/lb9qwsc "Last usage")|Low Earth Orbit (180-2000km)| | |Law Enforcement Officer (most often mentioned during transport operations)| |[NERVA](/r/Space/comments/1drde30/stub/lavrfmz "Last usage")|Nuclear Engine for Rocket Vehicle Application (proposed engine design)| |[NEV](/r/Space/comments/1drde30/stub/laxbpnn "Last usage")|Nuclear Electric Vehicle propulsion| |[NTP](/r/Space/comments/1drde30/stub/laxbpnn "Last usage")|Nuclear Thermal Propulsion| | |Network Time Protocol| | |Notice to Proceed| |[RCS](/r/Space/comments/1drde30/stub/law73n7 "Last usage")|Reaction Control System| |REL|Reaction Engines Limited, England| |[RTG](/r/Space/comments/1drde30/stub/lb0cgxt "Last usage")|Radioisotope Thermoelectric Generator| |[SABRE](/r/Space/comments/1drde30/stub/lav8lj2 "Last usage")|Synergistic Air-Breathing Rocket Engine, hybrid design by REL| |[SAFER](/r/Space/comments/1drde30/stub/lavbtvi "Last usage")|[Simplified Aid For EVA Rescue](https://en.wikipedia.org/wiki/Simplified_Aid_For_EVA_Rescue)| |[SSTO](/r/Space/comments/1drde30/stub/lauf699 "Last usage")|Single Stage to Orbit| | |Supersynchronous Transfer Orbit| |Jargon|Definition| |-------|---------|---| |[Starlink](/r/Space/comments/1drde30/stub/lavgsq8 "Last usage")|SpaceX's world-wide satellite broadband constellation| |[cislunar](/r/Space/comments/1drde30/stub/lauld85 "Last usage")|Between the Earth and Moon; within the Moon's orbit| |[cryogenic](/r/Space/comments/1drde30/stub/lavi0t5 "Last usage")|Very low temperature fluid; materials that would be gaseous at room temperature/pressure| | |(In re: rocket fuel) Often synonymous with hydrolox| |hydrolox|Portmanteau: liquid hydrogen fuel, liquid oxygen oxidizer| |[regenerative](/r/Space/comments/1drde30/stub/laxbpnn "Last usage")|A method for cooling a rocket engine, by [passing the cryogenic fuel through channels in the bell or chamber wall](https://en.wikipedia.org/wiki/Regenerative_cooling_\(rocket\))| **NOTE**: Decronym for Reddit is no longer supported, and Decronym has moved to Lemmy; requests for support and new installations should be directed to the Contact address below. ---------------- ^(18 acronyms in this thread; )[^(the most compressed thread commented on today)](/r/Space/comments/1dtdvsj)^( has 25 acronyms.) ^([Thread #10252 for this sub, first seen 29th Jun 2024, 16:28]) ^[[FAQ]](http://decronym.xyz/) [^([Full list])](http://decronym.xyz/acronyms/Space) [^[Contact]](https://hachyderm.io/@Two9A) [^([Source code])](https://gistdotgithubdotcom/Two9A/1d976f9b7441694162c8)

This is too open ended a question. One reason why something like JWST took so long to build was because it relied on technology that hadn't been developed when the program started--they literally had to develop new technology to complete the project as specified. There are a lot of theoretical technologies currently in development that could make space faring easier than it would be with current technology.

OP asks for "What could we build right now!" and everyone answers with future tech that is at the very least a few decades ahead of us. No we cannot currently make Space Elevators, or Plasma Drives or Laser Sails yet. Maybe we could do it in a reasonable timeframe if we really invested, but right now we simply cannot do it. Right now the only really fast propulsion system that would definitely work with our current tech if we disregarded the political fallout (heh) would be something like Project Orion. As for life sustaining tech, no, it isnt nearly there yet. Not even close, we can barely make a self-sustaining ecosystem that lasts a year or two. OP, if you are really interested in what is actually currently (and maybe soonish) possible instead of wild fantasies, you need to read this book: https://www.acityonmars.com/

Add fusion to that list. I laugh when I see people here say "with modern advancements we're seeing in fusion, 20 years for starship propulsion" when we're not even close to fusion here (really, we aren't, it's as close to "20 years in the future" now as it was 60 years ago) in facilities that are comparable in complexity to a particle collider and require their own power plant to run. Elevators and plasma drives and lasers sails are in the "not ruled out by known physics" stage, not the "not ruled out by practical/possible considerations" stage. Like graphene nanotubes are theoretically strong enough to maybe be used in a space elevator if you can figure out a way to manufacture them but that is just not something we're industrially capable of doing in this lifetime. We're at a "if you defunded a few national economies, you could build the ship from 2001: A Space Odyssey in a decade" level

This is why I just limited myself to materials technology we have today. Money can make VERY complicated systems eventually work, but we cant just spend our way into better quality materials.

> Could we get to all the planets and moons on the solar system? With separate ships for each one, sure - but with people on them? Our recycling tech is barely scratching the levels of cyclical efficiency required for it to not be a guaranteed death sentence. > Could we get to another star even if it takes us a few thousand years Name literally any technology that has survived that long other than pyramid-shaped piles of rocks and the occasional [sock knitting jig](https://images.theconversation.com/files/591500/original/file-20240501-22-41yiid.jpeg) or similar - or any cohesive society that hasn't shattered and reformed several times over.

>Our recycling tech is barely scratching the levels of cyclical efficiency required for it to not be a guaranteed death sentence. How? ISS water recycling is 98% efficient. That sounds very good to me. Not to mention that water ice is actually fairly abundant throughout the solar system, a bit of ISRU and I really don't see the issue

> ISS water recycling is 98% efficient. That 2% loss really adds up when you're thinking in time frames of centuries and millenia. For a thousand-year voyage, you would need to build a ship capable of carrying a huge amount of water. Then you would need to build it even larger to contain the necessary fuel to power a ship with that much water's worth of mass. PBS Spacetime did an episode addressing this whole topic (could we build a generation ship today, with our tech?) and they did the math on everything. Here's the link: https://www.youtube.com/watch?v=yWlpNm1C5gw

That's totally true, but the comment I replied to referred to interplanetary travel, not interstellar. With interstellar travel you're absolutely right, that adds up very quickly. But if it's within the solar system, you're looking at travel times of months or years, not millennia. Add onto that the ability to get water ice from places like the polar caps of Mars or the rings of saturn and I think water specifically isn't as much of a problem.

With infinite money(assuming no inflation because there definitely would be), you could probably make like 1000 starships a day and direct whole economies to work solely on space exploration. Like the other person said though. It’s not like we’re going to suddenly invent warp drives. Moon, Mars, and the moons of gas giants would be viable but a generation ship would need an established space manufacturing economy to source that many materials.

With infinite money inflation doesn't matter. Physical resource limitations matter

Not just physical resources but organizational limits. You can easily reach “too many cooks in the kitchen” and not be able to organize the engineering and manufacturing effort required to scale production. Throwing more money and people at the problem does not always make things progress meaningfully faster. It can sometimes have the opposite effect as responsibility is diffused and lost, and signals take longer to make their way to the people who can make decisions.

Agreed. We cant have infinite engineers/scientists/etc even with infinite money (and certainly wont have the capability to manage it all)

Sure but surely infinite money applies to space infrastructure too, infinite money means free education for everyone, entire economies devoted to sustaining the population then all excess, and there's a lot, goes towards space. All space exploration starts on the ground, from birth to space is where everything would go. Completely unrealistic obviously but hey it's the question that was asked.

Manpower matters too. If we setup programs now to ramp up our training capacity for tons of rocket scientists ;-), space engineers and astronauts, then we'll have a critical mass 5-10 years down the road. The following 10 years will be crazy with progress and in 20 or 30 years we might have the technology to send people beyond Mars. Beltalowda!

Why would inflation matter? Do you not understand the concept of infinity?

Resources are still limited in this hypothetical scenario. Whether we like it or not, money=incentive. When money is no longer the issue, logistics becomes the issue. People still need to eat/sleep. You could buy food for them, but then you’d have to pay someone to work the fields or transport it to the store .When money becomes infinite, it becomes worthless. So you have to find a different way to motivate them to do these things. It’s the law of supply and demand.

I would definitely be interested in developing experimental propulsion systems with unlimited money. Right now there are only like 2 different types of propulsion commonly used in space. Standard rockets which most commonly use forms of Hydrogen and Oxygen and burn it through a nozzle. These get very big very fast, and tend to be more 1 time use things. Then there is ion thrusters like the hall effect thruster which is great for making small adjustments on satellites. They require a lot of electricity for little propulsion, but consume a lot less fuel. You'd want to do a deep dive into the highest possible energy density for fuels on a propulsion system that could be obtained within the next 10-20 years. For Example: There are lots of claims that fusion is within our grasp. Everyone knows about ITER, but there are also other methods, like inertial confinement using lasers which would lend itself very nicely as a propulsion method. Rather than worry about capturing the energy and having worry about the Deuterium/Tritium reaction being quite dirty with lots of free Neutrons... you just direct all that energy and free neutrons in the opposite direction of where you wanna go. Likely the nozzles will still have a limited lifespan like every other propulsion method, but if you could use Deuterium+Tritium to achieve Hydrogen+Oxygen levels of force with a massively higher specific impulse, we'd be talking like 3-4 days to go to Mars, 8-9 days to go to Saturn, a ship that could just land on the surface of Mars or Europa, and take off again like it's no big deal. All that space on the craft that would normally be used for Hydrogen+Oxygen would instead have life support systems, supplies, a nuclear reactor, scientific equipment etc. You build a ship like that and make the entire solar system reachable as a week or month long business trip, not only could you do tons more research, but you could use these ships to start acquiring resources in the asteroid belt or on other planets. He3 for example can theoretically provide a much cleaner fusion reaction that doesn't irradiate the reactor like deuterium tritium does. But it tends to only build up in places with no atmosphere, like the moon. There would definitely be a technological renaissance that would happen. I don't think you bother setting your sights on exoplanets with humans until you achieve relativistic speeds and then maybe send some drones first in a trial run. So not likely in our lifetimes even with unlimited money and resources. There's just too much science to do first. But I think if humanity really focused all of our efforts into developing space, we could see asteroid mining and a lot more space jobs in our lifetime.

If you consider money to be a measure of the economic importance we put on any endeavor, in giving unlimited money to the project, we could reallocate massive chunks of our economy to the problem. If you then further assume you have 20 to 30 years to actually invest that money and see the return on the project itself... It's possible to go from building new universities and schools, to their graduates working on the hardest problems later down the line, to their children riding rockets into orbit by the millions. This is kind of what we have to assume would happen even with "current materials" because we would need to build factories in order to actually fabricate those materials into whatever we were designing. It's possible but expensive to convert a plastic mold forming plant into one capable of forming rolled steel or titanium alloys. Regardless of how you shake it though, we're looking at completely decimating the entire world's ecology to produce enough raw materials though. A more sustainable route would be a slow development of automated manufacturing for in-situ operations. Like the construction of one functional Von Neumann probe to fly into the asteroid belt, and build 2 more of itself before breaking down and needing maintenance drones to repair it. Unlimited budget means instead of a handful of experts doing computer modeling at a very relaxed pace, we get thousands of engineers all building whatever crazy shit they can think of. Every problem will get a solution but it will often be a very inefficient or environmentally dangerous solution to those problems that you end up with.

Now I kind of want to read a book about a society whose entire existence has become fixated around space travel, to the detriment of everything else.

My thought was basically Kerbal Space program. The kerbals don't even have homes outside of the space center :(

A lot is unknown because we haven't done it yet. So it depends on the amount of risk you want to take. A round trip to Mars feels plausible with relatively low risk. We could build a generation ship and sent it to a different star, but there are decent odds something will go wrong and everyone is dead before it arrives. I expect it would improve progress a lot, but it won't suddenly get in science fiction territory.

I'd say for a true long term viable self sustaining spaceship it would likely look like a large hollowed out chunk of moon rock or asteroid which could sustain a crew similar in organization to an aircraft carrier with nuclear reactor, large spaces dedicated to agriculture/hydroponics and water/ice with thick walls to insulate and protect from radiation along with environmental facilities. The size would need to be quite large in order to sustain itself but it can be done. Most of the cost would be spent on building up the base/facilities in order to carve out such a vehicle but it would be many times cheaper to burrow into a suitable existing object that can insulate reliably and make it mobile, than to manufacture a traditional idea of a spaceship and attempt to launch the parts from earth. The challenge would be to find suitable material to carve into which would both insulate and be resistant to impact from (micro)meteorites etc without cracking open like an egg and not be pourous or chemically dangerous to the inhabitants. Ideally we simply burrow into and carve out a chunk of Moon as proximity to earth etc would lend itself to timely construction, it could serve as its own manufacturing plant, theory can immediately be put in practice prior to embarkment and indoor space can be planned out more effectively, but if the moon rock is not suitable we would have to attempt to capture an asteroid which may have to be done repeatedly in order to find the one unicorn we can actually build upon. An idea to explore, if the object has sufficient mass, is to attempt to coat it or surround it with ice which could further protect the inhabitants as a rudimentary shield while breaking into a mist with any impacts which with any luck would orbit it further protecting it. This would also cause issues with successfully boarding the vessel but I'm sure we could work that out. It would also be a great source of water and essential to environmental systems. Solar sails and external sensor arrays can be used for navigation along with supplementary boosters.

Unlimited money would allow larger version of today's ships That could include a rotating habitat module. This would make Earth to Mars doable, without worrying about dying of kidney failure at the end of the trip. Unlimited money would also allow orbiting stations that people could move to and live. They could manufacture things that can only be manufactured in micro gravity, then come home to dinner in their 1G habitat.

Listen, I just want city ships. Preferably with space fold technology.

One that really wouldn't get us anywhere. There are theories that can get us to 30% the speed of light but the space ships would require constant maintenance and have a lifespan that is short. The ISS is going to be deorbited after 30 years and MOST of what the astronauts did was construction or maintenance.

A modular spaceship launched piece by piece and assembled in space. It's 500 ft long and has a large ring circling a long cylinder. The ring spins for simulated gravity, and the center is for experiments and the propulsion. It will use the Orion engine concept and propell itself on nuclear explosions. Go fly to Alpha Centauri.

I would start producing modules for a Dyson sphere and autonomous ships to move them into position. Then ant like robots which could run on the sphere surface maintaining it.. Then some nasty laser stuff to send the harvested energy where it is needed..

We may have unlimited money but not unlimited resources to build a Dyson sphere.

[orbital ring](https://www.youtube.com/watch?app=desktop&v=LMbI6sk-62E) edit: and [oneill cylinders](https://www.youtube.com/watch?v=hYyg8JC-6ew)

I think shielding is the universal limiting factor. Money doesn't stop gamma rays.

A 1m layer of water reduces radiation below earth levels. Did you know that human divers service the pools holding spent nuclear fuel rods? The dose of radiation 6’ below the fuel rods is lower than a person receives standing anywhere on Earth’s surface. Shielding is solved from a possibility standpoint. The problem is mass. Lots of ongoing research (including likely on the current x-34 mission that is currently intentionally flying through the Van Allen belts) is investigating both active and passive shielding materials and technologies to get the mass of shielding required significantly lower.

Solar System is doable right now. I'd like to set up a Foundry out in the Asteroid Belt for the big items wed need. Most all the stuff you need is available off planet, adding sustainable biome from Earth, DATA and High Tech, highly fabricated items, etc might need to be made 'at home'.

We could probably build a mostly self-sufficient nuclear powered colony ship.

SpaceX has been pushing what's possible, with a budget smaller than NASA's. I don't think unlimited money will speed up this development significantly.

Man, I need to get some rest, I misparsed the title as a "space farting spaceship".

So truly unlimited funds lets us get into nuclear rockets... we can afford the bribes! So we go to the asteroid charts and find us a nice nickel iron asteroid. We send a nuclear rocket powered probe out to it and we get it to orbit the moon. While that is happening we set up a nice lunar base to mine oxygen and aluminum. We build space mirrors and lunar orbital infrastructure in prep for the incoming asteroid. Now that it is here and we captured it in orbit we rotate it and then make it molten. This will spin it to create a hallow on the inside where we can make our generational ship. We might need to capture a comet in a similar fashion to supply gases and water. We can do gravitational slingshotting, solar sails, nuclear rockets, That technique where we drop a nuclear bomb out the back and set it off at the right moment for a push and/or a laser push to get up to speed and off to where ever we are supposed to go. Be it around our local neighborhood, the outer planets and the Oort cloud, or interstellar journeys... okay only outer planets or other stars, its way too big for local jaunts... but it would make a fun space station.

I loved buildtheenterprise.com when it was around. Essentially the star ship enterprise minus the warp drive. Rotating ring in the saucer hull for artificial gravity. Basically a giant rotating space station that can move around the solar system on long duration science missions. Also, kaplana one is another favorite of mine. Such a good space station design. I hope to see one built before I die. I believe we could get to all the planets in the solar systems, but I dont think we have the ability to get to other star systems reasonably. Not yet at least. (generation ships could work, but they have their own issues that make them a no go imo) I think chip manufacturing is the biggest hold back from a self sufficiency point. Everything else can be solved with unlimited money. I don't think you could make a small space station without some type of mining logistics for raw materials. Those raw materials could come from Earth, Asteroids, Moons, Other Planters, etc. You could probably make a self sufficient mars colony considering unlimited money. Our current lives consume a LARGE volume of raw resources that a space station just wouldnt have. 100% closed cycle systems dont exist yet.

Money! The O'Neil report outlined a proposal for building a permanent city in space with a population of thousands. The projected cost was 500 billion. Certainly too high a price to take the idea seriously! That number stuck in my head because a decade later the government managed to come up with that amount to bail out the savings and loan industry. The proposal seems reasonable to me. It involves building a mining and manufacturing facility on the moon and launching the pieces (using a magnetic driver) into a Lagrange point for assembly in space. The city (a cylinder or torus) would be about a kilometer in diameter and have a self sustaining life support system driven by solar panels. At least that was the proposal. It's a shame we put this project on the back burner for so long. I (and you) can think of so many ways to go from there.

Any nuclear salt water and laser sail fans? These could get us to proxima centaur while being in our reach.

[https://en.wikipedia.org/wiki/Project\_Orion\_(nuclear\_propulsion)](https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion))

Really, not much more than we have now. A lot of the limits are physical and not likely to change without some major discoveries.

The biggest current limit is cash. Ignoring starship as it is still a prototype, you could use the falcon heavy to put 60 ton modules into LEO and send up astronauts on crew dragon to assemble it with either canadarms or eva. If you are willing to smash the usual budgets you can stitch together as many modules as you want, because the falcon rockets are mass produced. So basically you can have any ship that can be created using modules that weigh 60 tons or less.

With Starlink type communication a bunch of space hardened GoPros and a bit of A.I. you could probably sit on earth and assemble the parts with canadarms.

At one point the structure would become unstable. E.g. i doubt you could build O'Neil cylinder or 1G Stanford torus with current materials without it falling apart. Thus you couldn't even build feasable generational ships.

Not true lol. There are loads of advanced concepts that require tons of cash but have been technically feasible since the 1950s, e.g. Project Orion.

As Keynes said last century, “Anything we can actually do, we can afford.” What we can do is limited by resources, both physical and intellectual. With an exception for things like anti-matter then physical resources probably aren’t a meaningful limitation. So the question ultimately reduces to what designs does humanity currently have available for space ships? We certainly don’t have a viable one for interstellar travel, not even for small probes. Though if all resources were devoted to improving technology in that regard then perhaps something small and unmanned like Starshot would be viable soon. Manned fusion power ships would be at least 20 years away (because fusion) though there are many other issues to solve too if you want to reach other stars. Manned travel within the Solar System is more feasible as there are a range of semi-plausible designs but none are really ready to go right away. SpaceX presumably has the most advanced design for that but it’s still only a paper design and not ready to be built right now. Ultimately, chemical rockets aren’t really the best technology for this but it’s the one that we currently know best.

Fusion small/light enough for starship is probably century or more away.

The biggest issue with anti matter is the cost to produce and store it. With unlimited funds, that opens up a whole new power supply.

The cost of antimatter is however strongly linked to the extremely low efficiency of the production process so it is also resource constrained to some extent. For example, [CERN](https://angelsanddemons.web.cern.ch/antimatter/making-antimatter.html) claims it takes a billion times more energy to produce antimatter than contained in the resulting mass. Current [global energy consumption](https://ourworldindata.org/energy-production-consumption) is about 180 PWh so if all of that was used to power antimatter production (at newly constructed CERNs) instead we could produce 180 MWh or 650 GJ of antimatter. In comparison, achieving escape velocity from Earth (11 km/s) takes about 60 MJ/kg, so the maximum annual supply of antimatter would only be sufficient to lift just under 12 tonnes into space… That’s a bit of a simplistic calculation but hopefully illustrates what I mean by resource constrained. There just can’t just isn’t even potentially enough antimatter available to do anything with it right now. Of course, with a lot of R&D that would likely change but it’s still in the distant future.

UNLIMITED? I'd say the wildest thing we could build is a giant fleet of generation ships assembled in orbit, made 99% self sufficient with countless redundancies, and then sent on a multigenerational exploration mission to nearby stars in search of inhabitable planets. It sounds absurd but we absolutely have the technology for this, it would just be very expensive and we'd need to have a lot of built-in redundancy.

Make a giant 18 meter fully reusable two stage orbital rocket. Launch it thousands of times a day. Then use it to build space elevators on Mars, the Moon, the largest asteroids, and the moons of Jupiter. Use the space elevators, and mines, to build even more space elevators. Use those mines and space elevators to build and supply giant rotating space stations. Eventually there's enough space stations and space elevators to support billions in space.

We can barely discern the conditions on exoplanets. I'd imagine that a prerequisite for interstellar travel (disregarding the ship required for such a voyage) would be to improve our observatories. No use colonizing a terrestrial world if it turns out that its red dwarf bombards it with flares regularly, or if the planet itself is a volcanic hellscape with no water.

We could build two massive space station ports that could be positioned around the earth and Mars and be used to have a spaceship travel between the two planets and constantly refueled by a steady supply of launches from earth sending fuel and supplies. It would be the most expensive thing the earth has ever done but it's completely doable right now. We could even make giant rotating stations to create artificial gravity that could be used as maternity wards and childhood raising to bypass issues with birthing and raising kids in low gravity of the moon and Mars.

The most "out-there" thing we could build is a viable interstellar generation ship, using nuclear propulsion (Project Orion etc). The beast would have to be built in orbit and would take a good portion of humanity's nuke stockpiles to run... but it'd be 100% feasible with our current tech. Other interesting things we could build include radio observatories on the Moon (imagine Arecibo but even bigger and in a farside lunar crater), a mega-bazinga space telescope (Webb on steroids), and a viable asteroid mining project. And loads of space stations, of course.

Apparently people believed they could build the Enterprise. I say we do that Article 12 years old.  https://www.universetoday.com/99164/white-house-petition-could-we-build-the-starship-enterprise/

Rrplace the ISS with a bigger better one. Build a moon base, while that's upgrading to basic industrial functions, send out a colony to Mars. Start work on a space Elevator to reduce emissions from rocket launches on Earth. Any out of solar system human exploration is out of the question really. Maybe a far flung research post.

Rocket propulsion is not the endgame. We need to research other types of propulsion mechanisms. This will take heavy investment in quantum mechanics and a blending of disciplines to produce.

Long story short: radiation and microgravity are going to be a problem on long journeys any farther than Mars. Any sufficient amount of radiation shielding isnt going to get up out of our gravity well, but we could maybe ignore that under your "infinite money" glitch. There's still the long term health effects of microgravity on the passengers. And I dont believe theres any propulsion available that can sustain 1g of acceleration for an entire trip.

Given the vast distance of space even within the solar system, research in high speed space travel would be one of the priority. A spaceship with a high-output nuclear powered plant would be good, something like those in nuclear submarines or carriers, strapped with ion thrusters or some kind of nuclear assisted rocket engines. It could be economical to build on earth and sent to space if SpaceX Starship is fully developed for large payloads. Some more breakthroughs in nuclear fusion would be very handy as well, since we can basically get hydrogen easily in space. By that point we can claim that we are a spacefaring species.

Just going off projects which have been bounced around in the last few years could have HOTOL with a SABRE engine for single stage to orbit. Then Project Prometheus - a nuclear powered ion drive platform feamework which modules could be attached to and is assembled in space as an orbiter to travel all the way out to Jupiter. This could also be used as a regular orbiting transport between Earth and Mars. The skills we have developed with the ISS means as should be able to construct almost anything modular in orbit, with the only limiting factor being getting stuff into orbit.

Bigger problem is radiation and propulsion and microgravity. Chea

Build a huge 1 mile wide orbiting ring space station. With the center open for docking. You can move it into any planetary orbit you want. As it rotates at 1 revolution per minute, generating its own artificial 1g gravity. Make it a triple walled Stainless Steel hull with thick multi-layer kevlar-polyethylene sheets between the stainless steel sheets for radiation protection. The windows are large ALON triple glazed evacuated windows with exterior radiation shutters. The crew sleeping areas have extra radiation shielding. A nuclear tug docks with and pushes the orbiting ring space station. The space station contains 3d printers, CNC machines, and several manufacturing centers. It contains probes to sample multiple exoplanets and moons. The mile wide ring section contains 5 levels. With the floors facing the center of the ring. The Nuclear Tug supplies tethered power. So it serves a dual purpose. A large telescope is available for close up observation, along with multiple HD cameras. Water and air are recycled, and supplies extra shielding if necessary. Food is grown hydroponically in the inner most sections.

Given the resources and tech we have now/are aware of, and avoiding making too many assumptions about what we’ll develop in the near future, I’d think an “Ark” style ship would be the way to go. A closed environment that would sustain itself (so, there’d have to be large oxygen-generating forest areas, water recycling, etc.. some way to generate energy (solar + hopefully something else)). AFAIK we haven’t successfully done this yet, because we’d love to even make a colony like this on the moon if we could. However, with unlimited budget, it could probably be figured out sooner than human FTL travel. If we could make a ship like this, it could conceivably take super-long term voyages spanning centuries. We wouldn’t need cryogenic tech or warp drive, we’d just need people to reproduce on the ship, so their kids or grandkids would be able to handle things when they finally got to Alpha Centauri.

Given TRUE UNLIMITED money and no bureaucratic yellow tape… it would be close to For All Mankind… but how the fuck would we quantify this if we never got the chance to make any real process. Like we haven’t even gone back to the moon in like 50 years?

The problem has less to do with money and more to do with time and resources. Getting something out of orbit is hard and consumes a lot of fuel. If a space elevator could be developed and we start production of ships outside of our atmosphere we could do all kinds of things. It is the fuel needed to get in and out of the atmosphere that is the problem.

Currently starship Superheavy is the “let’s take ridiculous risks because we’re so well funded “ project. If it wasn’t, they’d have built a raptor powered version of f9 and called it a day

Closest star system is 4 light years away. If we can go there at 1% the speed of light then we can reach it in 400 years. There are 84 star systems within 25 light years of us. If we poured time and money into colonizing our solar system we could get it done. Like the movie Ad Astra.

Depends, if we take human ego out of the equation and launch embryos into space with AI to navigate and raise the children we could colonize the entire Milky Way. It would grow exponentially, each new planet after 100 years sends 5 craft, they send 5 craft and so on.

A slightly larger version of what we have now. Maybe you build it in space and it's bigger, but money just won't invent new tech.

We should build giant destroyers that use an "alternate form of propulsion" already known to science, with Ai brains and machine vision systems as well as direct energy weapons. No I will not elaborate on the alternate form of propulsion. I don't want to disappear. I'm fond of being alive. Frustrated beyond words with society, but I love humanity and life anyway. Read the Iain m banks book series.

Sending a probe might be possible. There are proposals for accelerating tiny probes using large laser arrays that could bring them close to light speed. For the best results, you want the laser array in space or on the moon (so the atmosphere is not in the way). There is a lot of research needed to make this work though. Especially in creating a probe that can survive the trip. Sending Humans is completely out of the question with current technology and scientific understanding. We lack a lot of knowledge on how Humans can survive in interplanetary space (all long-time human space missions were within Earth's magnetosphere (aka radiation shield). Even though we tried we have not yet managed to create a fully self-sustaining closed system. We know almost nothing about interstellar space (the voyager probes indicate that there is more radiation and lots of magnetic storms). There are a million more questions that need to be answered first before we know if it is even theoretically possible.

Space is really big and space-time is really weird. You don't need a generational ship you just need a REALLY big gas tank. If you could accelerate at 1g half way to Proxima Centauri B, 4.22ly away, then turn around and decelerate at 1g the rest of the way you wouldn't need a generational ship because it would only take about 8 earth years or 3 ship years to get there (because you'd get up to about 0.83 light speed so time dilation comes into play) Problem is you'd need a gas tank 584,000 times larger than SpaceX's Super Heavy Booster. If we advance just a little bit into nuclear thermal engines we reduce the size of the mega fuel tank by roughly 31 times. Still 19,000 times larger than the largest rocket ever built. So going the other way around using current ship capacities we wouldn't get nearly as fast so it would take much much longer. How much longer? Well if you spent about a decade using our solar system to gravity assist you up to speed it would only take 8500 years to get there. Problem is you'd need to solve surviving in microgravity from birth to death for a small society of people. Which, in my opinion, is much harder to do.

[this one](https://youtu.be/pP44EPBMb8A?si=Vzg9yw1fNxdqPnVF)

[Project Orion is a Go!](https://en.wikipedia.org/wiki/Project_Orion_\(nuclear_propulsion\)) Ok, we still haven't figured out the fallout problem with the nuclear pulse propulsion system, so we'd have to launch from the lunar far side, but that's a minor inconvenience all things considered when you're building a starship the size of Manhattan Island.

Im going on the manned spaceflight front, but we would likely establish holdings in earths orbit and the moon. Orbital: With metal based 3d printing recently being done is space, we could likely begin developing that tech on large scales to print large habitats in orbit, artificial gravity rings would be developed to slow the effects of microgravity. Another method of inhibiting Earth's orbit could also be inflatable habitats. Large research stations would develop the tech needed to survive long-term interplanetary travel like better radiation shielding, life support, food growing, ect. Biotechnology would be revolutionized with the concept of printing usable organs being able to be properly tested. Lunar: With regolith 3d printing being tested on simulated lunar soil, we would see large research bases built on the moon within months. Probably only 20-40 people max would actually inhabit the bases at any given time, though I wouldn't expect cities for decades at least. We would see industry take place on the moon, like fabricating components for bases, mining deeper samples and Helium-3, and building roads or other infrastructure. If helium-3 is a good material for nuclear fusion, mining would become the backbone of a lunar economy, the moon would also serve as a prime launch site and command center for missions and logistics for the solar system. Interplanetary/infrasolar: we would see more probes and rovers in the outer system as we prepare for human Interplanetary missions. Asteroids would be captured in earth or lunar orbit and mined, bringing rare resources needed for technology and many other things. Hypothetical idea: a space vault would be developed similar to the seed banks in Norway holding seeds, copies of the human genome along with other animals from earth, perhaps even cryogenicly frozen humans, microbe samples, animals, and plants. This could likely be placed in a graveyard orbit where orbital decay would take millions/billions of years to fall into the earths atmosphere. My reasoning is that if earth were to be destroyed, either future humans, or extraterrestrials could find these organisms and possibly recreate/study them In all: in the next 20-ish years, humans would likely have a decent a infraplanetary hold with probes and rovers across the solar system with asteroid mining supercharging the global economy as we prepare for interplanetary manned missions

It's not the money, imo, but the assembly and manpower.

Given unlimited funds, the obvious first step is to build a ship-building station in orbit. We could build a ship to get around the solar system relatively simply, using water as reaction mass for steam thrusters. Power could come from either solar or onboard nuclear. If you're using nuclear anyway for power, you might as well use them directly for the engine steam. We haven't figured out lightweight radiation shielding yet, but if you're starting in orbit, you can build your ice-based fuel tanks around the living space, and there's your shielding. For interstellar trips, we run into a problem. AFAIK, we haven't cracked creating a stable contained ecosystem. We'd basically need to create an ecosphere on the scale of [Biosphere 2](https://en.wikipedia.org/wiki/Biosphere_2), if not larger. This is a problem we'll need to crack for in-system bases such as the Moon and Mars, but those locations can survive for a while on emergency measures until rescue missions reach them. On an interstellar trip, once the ecosystem collapses, you're fucked.

We're already flying through space with a lot of air, food, water and at a comfortable temperature. I'll just fly on this 'ship'.

Unlimited money? Matter-antimatter annihilation drives.

None. Billionaires during their space race on their way to becoming trillionares couldn't build any ships with their unlimited money... What do you think has changed. The realistic question would be with unlimited imagination.

I don't think it's an issue of money. Such a spaceship would have to be entirely self-sustained, self-powered and eminently self-repairable. These are just problems we haven't solved. How do you produce food on a space ship without devoting an unreasonable space to hydroponics? How do you recycle air, water and everything else ad infinitum? How do you power (both electricity and propulsion) the ship for long durations? It's science fiction right now. List all the problems and you get a tome that'll break your toe if you drop it. Could we eventually solve all these problems? Yes. Have we? Very no. Even given that unlimited money it would probably take a century of constant development just to have your first deep space mission. There are also very human things to consider. Generational ships can be seen as a form of slavery, dooming generations to a life they didn't consent to. And all it takes is one miscreant to doom the mission. It's easy to screen miscreants from the first generation, but the rest is just up to chance.

We'd probably build orbital tether or some sort of EM launch system. Something like this: [https://en.wikipedia.org/wiki/StarTram](https://en.wikipedia.org/wiki/StarTram) Though on the other hand if money (= resources) were infinite, would there really be a point in reducing the launch cost? If it was truly infinite we could just launch anyone on a Space Shuttle or some other capsule, so the question is a bit flawed.

Not so fast! Unlimited money isn't infinite. At best, you're going to have perhaps a trillion dollars. Maybe a few trillion if everyone on earth contributes. That doesn't get you very far on the galactic scale. Not with the costs involved today. A few trillion dollars doesn't get you ***any*** of the stuff the people in the comments are talking about (generation ships, fleets of interstellar ships, etc...).

With unlimited funds, we could indeed design a more advanced spacecraft capable of extensive solar system exploration and potentially reaching another star, although it would still be an immense challenge given our current technological and material constraints. # Exploring the Solar System For solar system exploration, we could feasibly construct a spacecraft designed for long-duration missions to various planets and moons. This spacecraft would likely include: * **Advanced Propulsion:** Utilizing nuclear thermal propulsion (NTP) or even nuclear electric propulsion (NEP) could drastically reduce travel times within the solar system compared to conventional chemical rockets. * **Robust Life Support Systems:** These systems would need to be highly reliable and regenerative, capable of supporting a crew for years by recycling water and air, and possibly incorporating hydroponic or other bioregenerative systems to grow food. * **Radiation Shielding:** Long-duration space travel exposes crews to significant cosmic and solar radiation, so advanced shielding (possibly using water or specialized materials) would be critical. * **Automated Systems and AI:** To maintain the spacecraft, handle routine operations, and support navigation and scientific experiments. # Reaching Another Star The prospect of interstellar travel—even with unlimited funding under current technological constraints—remains daunting and would involve timelines spanning many generations: * **Generation Spaceships:** These would be massive structures capable of supporting thousands of people for centuries. They would need to be nearly self-sustaining ecosystems, with extensive life support and recycling systems. * **Propulsion:** Reaching another star system within a timeframe of a few thousand years would require propulsion systems far beyond our current capabilities. Possibilities might include antimatter propulsion, which could theoretically reach appreciable fractions of the speed of light, or even speculative concepts like fusion-driven engines. * **Autonomous Maintenance:** Given the time scales involved, such a spacecraft would need highly advanced automation and perhaps AI to manage onboard systems, perform repairs, and potentially manage social structures. # Sustainability and Self-Sufficiency Creating a completely self-sustaining spacecraft presents huge technical and ecological challenges. Closed ecological systems on Earth (like BIOS-3 or Biosphere 2) have provided valuable insights, but none have yet operated indefinitely without external inputs. A space-based version would need to be far more efficient and reliable. # Reality Check While we can imagine the outlines of such missions with unlimited financial resources, the technical, physiological, and psychological challenges remain immense. The feasibility of such projects with current technology would still be low, particularly for interstellar travel. Advances in materials science, propulsion technology, life support, and ecological cycling would be necessary before such missions could be realistically planned. In summary, with current Earth-bound resources and technologies, extensive exploration of the solar system seems achievable with sufficient funding and time. Reaching another star, however, remains firmly in the realm of the distant future and speculative science.

SpaceX is planning to make 1 Starship a day. Each Starship can lift 250 tons, or 100 people. Inflatable bus sized space station modules already exist, are scalable, and are designed to fit into Starships. Those modules can be purposed for any type of space craft. Space exploration is only limited by money, willpower, and engines for interplanetary travel.

Project Orion I guess. Just nuke our way to Andromeda.

Nobody has figured out how to deal with the extreme radiation.

I would love to see a full scale project orion from the 1960s with a crew of about 1000 people. Nuclear all the way. Well I like the ship not so much the nuclear fallout.

not much. i am assuming you're talking about what we could design and build with no additional technological development. for a simple trip to Mars to walk around and pick up samples we would need to solve the muscle atrophy problem. we are not close to a medical solution and while we know spin gravity will work we haven't begun to find and resolve the engineering challenges that come up during practical testing. with unlimited money and 10 years to do practical testing, we could get a lot of solid theories to actually implement technology and probably start construction on an interstellar ark ship.

Probably not much better than Musk’s heliocentric Tesla Roadster.

We could definitely build generation ships utilising different types of nuclear rockets. The biggest issue would probably be shielding and understanding where we're actually sending it/what it'll do once it gets there.

I reckon it would look a lot like your average KSP run. Hardest would be the human factor of distance and duration. Economics come out to be a part of it but no matter how standardised, that run to Mars ain't getting any shorter. Now argument is for more efficient technology and longer burns, but even that wouldn't completely remove human issues. Would I become a space trucker? Fuck yes. But I suspect in the grand scheme of things number of people genuinely ready to live that way is limited.

Why, what do you know that you're not telling us? Did we actually elect a giant asteroid for president?

Fusion reactor research. Make it happen!  The largest peoject out there - ITER, which is collaboration of numerous countries, is a mere 65 billion $ in costs.  Imagine if it had like 1 trillion $ investment?

To leave our solar system? We haven’t developed a sufficient shield to cosmic radiation yet. Any current solution involves a thick wall of water completely enclosing the ship which comes with a wide range of problems from weight to the size of the vessel and of course *keeping the water from freezing in space climate (or lack thereof)*. Until we figure this out propulsion would be absolutely useless beyond flying around our own system that includes the one habitable planet.

Well, Blue Origin could produce some wonderful pictures… /s