how far could we go with current technology but infinite resources?

[king of nowhere]

As I'm trying to perform grand tours with increasingly realistic mods, I occasionally got into arguments on how realistic it would be to try a grand tour with current technology. I mean, we barely walked on the moon a half dozen times, we're still a long way from mars, manned missions to the most distant planets are clearly off the table for a long while, aren't they?

I counter that by claiming that our current technology (including stuff we don't have but could easily develop if needed) would be actually good enough to go everywhere in the solar system, it's just too expensive and unpractical. But that's a discussion concerning real rocketry, so i'm bringing it to the appropriate thread.

Would we be able to launch manned missions everywhere in the solar systems with current technology, if we had infinite money and industrial capacity and no risk aversion?

My understanding of current technology is that yes, in theory we could. Let's see the main obstacles

1) crew healt in 0 g is the main problem.

i read multiple times that a gravity ring would not work, that the coriolis effect would be so strong that it would make people nauseated.

On the other hand, I don't think anyone has ever tried to make an actual gravity ring and have astronauts living in it. With infinite money and industrial capacity, we could afford to build one big enough for crew healt. Even if it weights 10k tons, and we'd then need a million tons of fuel to move it, for the purpose of this experiment it is possible.

but ok, let's assume it really is not, and that we have to keep our crew in 0 g for a decade or two. we don't really know the long term human tolerance to 0 g. the longest permanence in space is one and a half year. and we don't dare push it too far, because we are afraid we'll make a mess. you can't risk your astronauts becoming crippled. even if you could, public opinion would see you without funding if you tried.

but assume the "no risk aversion" clause; in this thought experiment we can and we will jeopardize our astronauts. would 0 g actually kill them? not that I know. not directly, at least. Sure, they'll get weaker muscles, even with exercice, but they won't actually need big muscles. Earth has the strongest gravity in the system, barring the gas giants where we won't land anyway. second highest is venus, and you get there in less than one year, while our astronauts are still in a fairly decent shape. everywhere else it's no more than 0.3 g, and outside mars orbit there's nowhere with more than 0.15 g on the surface. Even if our astronauts were strongly weakened by their permanence in space, they'd probably still manage to walk on those places. even weighted down by their eva suits.

i'm not even considering radiations. We can afford to cover the whole ship in lead plating, and to hell with weight. We have infinite resources for something.

2) deltaG seems doable

it would take a few tens of km/s to go anywhere in the solar system. Well, if we have no weigth/cost restriction and we can send thousands of tons of fuel in orbit, that's not a big deal.

3) ship maintenance

my knowledge is much more hazy in this field. However, we've managed to launch robotic ships that lasted decades. Add in that no mass restriction means you can afford to send plenty of redundant systems and spare pieces, and that you will have a crew to take care of repairs, keeping a spaceship in working conditions for 30 years seems plausible. Life support is also something you can brute force your way through, just bring enough food, air and water. Of course we would never want out poor astronauts to spend 30 years in space away from their families and everything else, but in this thought experiment, this is not a concern.

4) energy

solar panels are useless too far from the sun, and rtgs are not suited for large ships. But we do have nuclear energy, and while we never tried to launch a nuclear plant in space, i see no particular reason why we couldn't. It's enough within the limits of current technology for my purposes

5)  engine reusability

engines can only be reused a finite amount of times. I'm not sure if astronauts in eva would be able to repair them.

worst case scenario, the mission would just carry extra engines and add some mass.

6) various, planet-specific

the cold of the outer system would not be a big deal, with a nuclear reactor we can afford to heat the ship. heat is harder to deal with. Venus is a brutal environment; I don't think our current technology would allow us to stay for long. but the venera probes managed to survive a few hours on the surface before overheating, and a sufficiently insulated manned lander may be able to achieve the same. the astronauts could eva in heavy diving suits - we have some that could withstand 90 bars of pressure, and buoyancy could help counteract the weight - long enough to grab a few samples and plant a flag. to return to orbit, deploying some sort of air baloon to float up away from the heaviest part of the atmosphere could help.

That said, i'm still uncertain about venus. i know we can make a probe that can survive a few hours in those conditions, and i know we can make an eva suit that can survive at the right pressures and at the right temperatures; but I'm not sure those materials would withstand pressure and temperature together. Not and stay light enough to grant some mobility just with the buoyancy. so perhaps we'd have to skip venus

Mercury has some similar problems. Going eva would not be a big deal, you can pick a landing site in twilight. the ship would certainly need a sunshade, and to get enough deltaV we'd need ion engines. but again, it's nothing we haven't done already, we'd just need to do it in bigger scale.

Jupiter has huge radiation belts; I'm not sure how lethal exactly they would be to humans, but as I mentioned before, at worst we'll just plaster every crew space with thick lead insulation, and then double the amount of fuel to keep the deltaV requirements

Conclusions

I do believe, if we could afford to launch ships in the tens of kilotons weight range, and we were willing to send our astronauts in very long, dangerous missions, then we could make manned landings everywhere in the solar system - or at least we'd have a good shot at them. with the possible exception of venus.

Prove me wrong.

[cubinator]

Venus is perfectly habitable, provided you live in a balloon 50km up.

[adsii1970]

1 hour ago, king of nowhere said:

My understanding of current technology is that yes, in theory we could. Let's see the main obstacles

One of the main obstacles you forgot is radiation.

https://www.nasa.gov/feature/goddard/real-martians-how-to-protect-astronauts-from-space-radiation-on-mars

https://www.space.com/5190-space-radiation-deadly-mars-mission.html

https://www.smithsonianmag.com/science-nature/radiation-remains-problem-any-mission-mars-180959092/

I do not mean to throw a bucket of water on your observations, but this will have to be something we must develop some technology to mitigate. Sure, most every obstacle you've listed could be overcome with unlimited funding and carrying enough spare parts or even using in-mission rendezvous to refuel and resupply the main mission vehicle. But the radiation exposure

Whether it is some sort of magnetic shielding using "Star Trek" style shielding consuming a lot of electric power, or heavy radiation shielding construction, or a combination of both, we simply are not to the level of technological development to safely land crewed flights outside of a lunar target. If you read some reports from the Apollo program, this was a huge fear - a solar eruption which could potentially cook the astronauts with higher than safe levels of radiation.

 

[Spacescifi]

2 hours ago, king of nowhere said:

As I'm trying to perform grand tours with increasingly realistic mods, I occasionally got into arguments on how realistic it would be to try a grand tour with current technology. I mean, we barely walked on the moon a half dozen times, we're still a long way from mars, manned missions to the most distant planets are clearly off the table for a long while, aren't they?

I counter that by claiming that our current technology (including stuff we don't have but could easily develop if needed) would be actually good enough to go everywhere in the solar system, it's just too expensive and unpractical. But that's a discussion concerning real rocketry, so i'm bringing it to the appropriate thread.

Would we be able to launch manned missions everywhere in the solar systems with current technology, if we had infinite money and industrial capacity and no risk aversion?

My understanding of current technology is that yes, in theory we could. Let's see the main obstacles

1) crew healt in 0 g is the main problem.

i read multiple times that a gravity ring would not work, that the coriolis effect would be so strong that it would make people nauseated.

On the other hand, I don't think anyone has ever tried to make an actual gravity ring and have astronauts living in it. With infinite money and industrial capacity, we could afford to build one big enough for crew healt. Even if it weights 10k tons, and we'd then need a million tons of fuel to move it, for the purpose of this experiment it is possible.

but ok, let's assume it really is not, and that we have to keep our crew in 0 g for a decade or two. we don't really know the long term human tolerance to 0 g. the longest permanence in space is one and a half year. and we don't dare push it too far, because we are afraid we'll make a mess. you can't risk your astronauts becoming crippled. even if you could, public opinion would see you without funding if you tried.

but assume the "no risk aversion" clause; in this thought experiment we can and we will jeopardize our astronauts. would 0 g actually kill them? not that I know. not directly, at least. Sure, they'll get weaker muscles, even with exercice, but they won't actually need big muscles. Earth has the strongest gravity in the system, barring the gas giants where we won't land anyway. second highest is venus, and you get there in less than one year, while our astronauts are still in a fairly decent shape. everywhere else it's no more than 0.3 g, and outside mars orbit there's nowhere with more than 0.15 g on the surface. Even if our astronauts were strongly weakened by their permanence in space, they'd probably still manage to walk on those places. even weighted down by their eva suits.

i'm not even considering radiations. We can afford to cover the whole ship in lead plating, and to hell with weight. We have infinite resources for something.

2) deltaG seems doable

it would take a few tens of km/s to go anywhere in the solar system. Well, if we have no weigth/cost restriction and we can send thousands of tons of fuel in orbit, that's not a big deal.

3) ship maintenance

my knowledge is much more hazy in this field. However, we've managed to launch robotic ships that lasted decades. Add in that no mass restriction means you can afford to send plenty of redundant systems and spare pieces, and that you will have a crew to take care of repairs, keeping a spaceship in working conditions for 30 years seems plausible. Life support is also something you can brute force your way through, just bring enough food, air and water. Of course we would never want out poor astronauts to spend 30 years in space away from their families and everything else, but in this thought experiment, this is not a concern.

4) energy

solar panels are useless too far from the sun, and rtgs are not suited for large ships. But we do have nuclear energy, and while we never tried to launch a nuclear plant in space, i see no particular reason why we couldn't. It's enough within the limits of current technology for my purposes

5)  engine reusability

engines can only be reused a finite amount of times. I'm not sure if astronauts in eva would be able to repair them.

worst case scenario, the mission would just carry extra engines and add some mass.

6) various, planet-specific

the cold of the outer system would not be a big deal, with a nuclear reactor we can afford to heat the ship. heat is harder to deal with. Venus is a brutal environment; I don't think our current technology would allow us to stay for long. but the venera probes managed to survive a few hours on the surface before overheating, and a sufficiently insulated manned lander may be able to achieve the same. the astronauts could eva in heavy diving suits - we have some that could withstand 90 bars of pressure, and buoyancy could help counteract the weight - long enough to grab a few samples and plant a flag. to return to orbit, deploying some sort of air baloon to float up away from the heaviest part of the atmosphere could help.

That said, i'm still uncertain about venus. i know we can make a probe that can survive a few hours in those conditions, and i know we can make an eva suit that can survive at the right pressures and at the right temperatures; but I'm not sure those materials would withstand pressure and temperature together. Not and stay light enough to grant some mobility just with the buoyancy. so perhaps we'd have to skip venus

Mercury has some similar problems. Going eva would not be a big deal, you can pick a landing site in twilight. the ship would certainly need a sunshade, and to get enough deltaV we'd need ion engines. but again, it's nothing we haven't done already, we'd just need to do it in bigger scale.

Jupiter has huge radiation belts; I'm not sure how lethal exactly they would be to humans, but as I mentioned before, at worst we'll just plaster every crew space with thick lead insulation, and then double the amount of fuel to keep the deltaV requirements

Conclusions

I do believe, if we could afford to launch ships in the tens of kilotons weight range, and we were willing to send our astronauts in very long, dangerous missions, then we could make manned landings everywhere in the solar system - or at least we'd have a good shot at them. with the possible exception of venus.

Prove me wrong.

You don't need a gigantic gravity ring to get gravity from rotation... all you need is to separate the main ship into halves with a kilometer long tether and rotate the halves at 1 RPM (1 rotation per min).

 

Only downside is you can only do this while drifting... not accelerating.

[king of nowhere]

1 hour ago, adsii1970 said:

One of the main obstacles you forgot is radiation.

https://www.nasa.gov/feature/goddard/real-martians-how-to-protect-astronauts-from-space-radiation-on-mars

https://www.space.com/5190-space-radiation-deadly-mars-mission.html

https://www.smithsonianmag.com/science-nature/radiation-remains-problem-any-mission-mars-180959092/

I do not mean to throw a bucket of water on your observations, but this will have to be something we must develop some technology to mitigate. Sure, most every obstacle you've listed could be overcome with unlimited funding and carrying enough spare parts or even using in-mission rendezvous to refuel and resupply the main mission vehicle. But the radiation exposure

Whether it is some sort of magnetic shielding using "Star Trek" style shielding consuming a lot of electric power, or heavy radiation shielding construction, or a combination of both, we simply are not to the level of technological development to safely land crewed flights outside of a lunar target. If you read some reports from the Apollo program, this was a huge fear - a solar eruption which could potentially cook the astronauts with higher than safe levels of radiation.

 

i did mention that. i mentioned that it could be brute-forced with enough radiation shielding. something real space agencies cannot do because of mass issues

[Bej Kerman]

3 hours ago, king of nowhere said:

As I'm trying to perform grand tours with increasingly realistic mods, I occasionally got into arguments on how realistic it would be to try a grand tour with current technology. I mean, we barely walked on the moon a half dozen times, we're still a long way from mars, manned missions to the most distant planets are clearly off the table for a long while, aren't they?

We have the technology to do a grand tour - see Orion and Ion tech. Just that we get caught up with money, development and safety. Orion couldn't possibly exist now with the nuclear treaties, Ion tech is somewhat underdeveloped and a chemical rocket big enough for a grand tour would cost too much for governments to bother with.

[magnemoe]

1 hour ago, Bej Kerman said:

We have the technology to do a grand tour - see Orion and Ion tech. Just that we get caught up with money, development and safety. Orion couldn't possibly exist now with the nuclear treaties, Ion tech is somewhat underdeveloped and a chemical rocket big enough for a grand tour would cost too much for governments to bother with.

Grand tours is simply an show of how Kerbal you are anyway. 
I did an grand tour without refueling back then it was no reentry heating. 
Now an grand tour like Jool 5 makes sense.

Main issue here is definition of current tech. As I see it Starship is current tech, Orion pulse nuclear is not, but nerva is probably current tech.
Note you could probably make an orion pulse nuclear engine where the charges was completely dumb.  you spin them up and hit it directional antennas with enough energy to set off the device two detonators. 
Its still an  low technological readiness level. 

[Nuke]

anywhere. with unlimited nuclear warheads fuel, you can go anywhere.

whether or not the universe is in heat death when you get there or not is an excersise for the reader.

Edited September 16, 2021 by Nuke

[razark]

As long as you don't violate the laws of physics, you can do anything with infinite resources.

Whether it's practical, easy, or worth doing is a a completely different question.

[Nuke]

14 minutes ago, razark said:

As long as you don't violate the laws of physics, you can do anything with infinite resources.

Whether it's practical, easy, or worth doing is a a completely different question.

infinite resources is by definition a violation of the laws of physics. if we had infinite resources here on earth, we would quickly collapse into a black hole of infinite mass. the universe would be doomed! might as well divide by zero and then multiply the result by infinity. 

Edited September 16, 2021 by Nuke

[kerbiloid]

14 hours ago, Spacescifi said:

You don't need a gigantic gravity ring to get gravity from rotation... all you need is to separate the main ship into halves with a kilometer long tether and rotate the halves at 1 RPM (1 rotation per min).

Hanging the whole ship mass on a single tether in a near-g gravity.

A thick tether is needed, and a big drum for it...

Of course if it hadn't wrapped like a bolas on the angular acceleration or on the CoM position changing..

P.S.
A challenge for irl.

Lift a battleship by a single tether.

[Hannu2]

Do you allow any development? Or should every machine be something already built? If you think about rotating space stations you probably allow some development. I think that if we could build proper fission reactor for space (which is currently much more political issue than technical), we could accept high loss rate of missions and the fact that astronuts would get permanent injuries on their missions (for example radiation damage) and we used all possible resources we could make manned operations on all planets in few decades with current production rate.

It would be nothing new. On expedition era kings and rich people sent ships and crews after another. Most of them were lost or just few participants came back without gold. But few successes made it profitable.

I think current era of unrestricted capitalism without ideological objectives will end sometimes and then humankind (or strongest states or richest or mightiest  persons) will have such objectives again. What could be better ideological objective for technical civilization than expanding to another bodies in their solar system (and maybe beyond if it will be possible) at any cost.

 

[mikegarrison]

What do you mean by "current technology", anyway? Arguably an Orion ship is within our current technology, but it's still at a very low TRL. https://en.wikipedia.org/wiki/Technology_readiness_level

If you mean "TRL 9" -- technology that we have actually already used in service -- then it's pretty clear that Mars is a huge stretch. Anything beyond that simply requires life support technology we've never had to develop. We're talking mission durations in years or decades.

[king of nowhere]

Ok, it appears most people agree that with "infinite resources" we could do pretty much anything in the solar system. Let's try to refine this a bit; how big a ship would need to be to provide a safe mission to

a) the moons of jupiter (main hazards: travel time, radiations, deltaV)

b) venus surface (main hazards: making a lander that can survive venus and get away from it

c) pluto, or other similar TNO (main hazar: travel time)

a thousand ton in LEO? ten thousands? one million? what would it actually need?

I'd like to try answers myself, but i'll have to leave in 10 minutes

58 minutes ago, mikegarrison said:

What do you mean by "current technology", anyway? Arguably an Orion ship is within our current technology, but it's still at a very low TRL. https://en.wikipedia.org/wiki/Technology_readiness_level

If you mean "TRL 9" -- technology that we have actually already used in service -- then it's pretty clear that Mars is a huge stretch. Anything beyond that simply requires life support technology we've never had to develop. We're talking mission durations in years or decades.

wasn't aware of tech readyness level; it's a nice concept.

my concept of "currently available" means that you can gather a bunch of engineers, give them enough money to develop the thing, and you are pretty much guaranteed that they will have a working prototype within a few years.

In that classification, it can mean anything between level 3-7. Something that we know would work, we have a pretty good idea of how to make it work, even though we may have not built a prototype yet.

As an example, I would consider nuclear engines and nuclear power plants to be something within current level; for the first, we built a prototype and tested it, and for the second, we have them working on the ground and we have to adapt them for space. On the other hand, i would not consider an orion drive to be within current level; though we know the principles under which it would work, there are too many practical problems in trying to propel your ship with nearby nuclear explosions. Nor I would consider available nuclear fusion, even though they are building test reactors, because they predict it will still take many decades to use them. Or generation ships, we can build stuff lasting decades, but not millennia.

[kerbiloid]

In zero-g a human has spent about 1.5 years.
They hope that a small physiotherapeutic centrifuge (4..6 m in diameter inside a pressurized compartment) can expand this up to a Martian flight, i.e. 3 years.
The permanent artifical gravity requires the 100..200 m radius of rotation, so is available only on the very large ships, unavailable before the mature thermonuclear epoch.
The elastic scheme of artificial gravity (a tether) isn't viable due to the reasons mentioned above.

So, the zero-g limits the flight duration with 2+..3- years.

***

The radiation. The long-term expedition should withstand the galactic rays (mostly gamma) and the solar wind (mostly protons, also causing the secondary rays in the hull).

The ESA Martian project considered ~27 g/cm2 layer density relatively safe (which means that the lifespan of the crew not to get shortened by more than several years).

This means that longer trips would need more thick hull and electromagnetic protection, or be significantly shorter by being much faster.
Hardly or not available before the mature thermonuclear epoch.

***

The orbital stations use the semi-closed life support cycle since early 1970s (Almaz was regenerating the water/oxygen.)

For a multi-year trip with greater crew they need more powerful and more closed regeneration system.

They can't grow food onboard (except the onions at the windows), so the food amount is limited and requires more advanced preservation technologies, including refrigerators, as sublimated powder is not the best and healthy food, while wet conserves need steel cans. This all means additional mass.

The crew needs several kilograms of expendable clothes and towels per humanday.
This means either a large store of clothes, or growing cellulose and a weaver/tailor (not Aliens) robomachine. Currently only the first.

The humans need a bath, because they would fly longer than 1.5 years.
This means that a water regeneration system productivity should be improved by orders of magnitude.

The same with janitor needs. The ship will be huge, and most of efforts would be spent on the house-keeping.
Actually, the personnel will consist of  janitors-bodybuilders with shading out remains of professional knowledge and experience.
Because they won't be doing science, piloting, and everything other for years, but their only occupations will be cleaning the floors and cardiovascular and muscle exercises in the gym.

This also means a lot of dirty water to regenerate and a lot of dirty clothes to burn and turn into water and carbon.

The ISS is flying about twenty years. And its toilets get broken yearly. 
Not a large problem when you can escape to the closest toilet at 500 km below, but at 0.1 AU  from the Earth this will turn the vessel into a craptank.
So, the life support system should be not just much more powerful, but also redundant.

***

The qualification of the crew specialists will get lower and lower without practical experience, so several years of doing nothing professional will turn them from academicians into technicians and affect the scientific abilities of the expedition.

***

So, any crewed flight should be shorter than 3 years in any case. With or without the radiation, gravitation, greenhouse, etc.

The Martian expedition is a golden standard for any actual expedition.

• 8 months to there.
• 1.5 years there.
• 8 months from there.

3 years in total.

The only thing which can be changed is that the flight distance will be increasing with ISP and thus delta-V.

***

Currently even the Mars is hardly accessible by chemical and hardcore nuclear engines/powerplants.

With gascore nuclear engines the nearest asteroids in the belt can be visited.

The Jupiter and the regular asteroid flights require at least a thermonuclear engine, which is not present, and probably will appear by the late XXI.

***

So, the only places accesible until XXII are: Moon, Mars (together with the Ph.D. moons), Venusian orbit, near-Earth asteroids. Nothing unexpected.

***

The infinity of the resources make it easier, as we can build a tower from infinite amount of TV sets and toasters, to walk to the Mars by feet.

[mikegarrison]

9 hours ago, king of nowhere said:

In that classification, it can mean anything between level 3-7. Something that we know would work, we have a pretty good idea of how to make it work, even though we may have not built a prototype yet.

OK, but one thing to understand is that especially at low TRLs, things can fail. Not just "take a lot of time and money to make it happen", but outright fail. There can be problems we haven't found yet that simply prevent this great idea from actually working.

[insert_name]

The technically correct answer is that infinite resources on earth would have enough mass to bring the entire universe into Earth, and probably destroy the space time continuum