What would be the impact on modern civilisation be if a benevolent inventor gave the world the ability to travel around the solar system quickly and cheaply.

If over the next five years this technology was built and tested by the likes of Space X and proven to work, meaning that with a powerplant the size of a small car, it became possible to transfer loads from the surface of one planet to any other in the solar system in a matter of days / weeks.

The technology is open sourced, relatively simple to build, even by technically proficient, moderately funded amateurs


For whatever technical limitation, the maximum carrying capacity of the powerplant is 50 tonnes. Including the vessel. It is not possible to use the powerplants as a group to improve that limit.

While it is clearly capable of impressive speed, it has a very limited range, which just happens to be about the size of the solar system. i.e. its thrust is time constrained, at maximum speed its fuel quickly degrades, meaning it wouldn't be able to stop if further travel were attempted

What are the economic, political and social changes that this technology would produce over the next ten years.


The idea behind the weight limit is to make it akin to a small truck / coach. It could either move a bunch of stuff, or a bunch of people. But would make large scale mining operations etc less likely. There would also be a 'there and back' usability. So you could jump in your space craft on the back streets on Birmingham, take a trip to Neptune, and make it back home again.

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    $\begingroup$ Where is your border of solar system? See en.wikipedia.org/wiki/Solar_System#Boundaries $\endgroup$
    – Mołot
    Aug 21, 2016 at 13:09
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    $\begingroup$ To be generous, let's say two months to Neptune at closest possible approach, about 14 AU away. (Semi-major axis 30.1 AU.) That's in excess of 400 km/s attainable average velocity. (A naiive calculation says 405 km/s for a 60-day trip, but spacecraft don't travel in apparent straight lines. In practice, it will be faster.) A 50,000 kg projectile moving at, say, 500 km/s in a relevant reference frame, now that is some serious momentum! Any projectile like that will be a weapon of mass destruction, or worse, regardless of payload. $\endgroup$
    – user
    Aug 21, 2016 at 15:22
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    $\begingroup$ It is not possible to use the powerplants as a group to improve that limit. But you can improve that limit anyway by grouping ships $\endgroup$
    – Michael
    Aug 22, 2016 at 0:54
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    $\begingroup$ I know what you're trying to do, but just a to throw a spanner in the works with the 50 tonne limit - 50 tonnes in Birmingham is a lot different from the same 50 tonnes on Neptune, which is again a lot different to the same 50 tonnes in space. Which is your spacecraft capable of moving? $\endgroup$
    – komodosp
    Aug 22, 2016 at 7:44
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    $\begingroup$ Why the distance limit? The way you want to enforce it totally screws with physics (all inertial systems being equal is fundamental both to newtonian mechanics and special relativity). Since the nearest star is 4 lightyears away, it'd take two millennia to go there at 500 km/s, so you probably don't need such a limit. Alternatively you could have fuel that always decays at the same rate, regardless of velocity but can be replenished at the destination/planets. That way you can brake at neptune and fly back with the replenished fuel, whereas you would be unable to break at alpha centauri. $\endgroup$ Aug 22, 2016 at 8:58

5 Answers 5


The true limitation here isn't time or distance, but rather the amount of stuff you could carry. A 50 ton spacecraft isn't very big, and since this is the all up limit, including astronauts, life support and everything else, missions will be limited to whatever can be packed into a very small mass budget.

So the first thing this would drive is the quest to miniaturize everything. Closed Life Support Systems would have to be miniaturized so the astronauts are not stuffed into a capsule filled with plumbing, or constrained by having a train of other spacecraft following them full of MRE's and Oxygen bottles so they can actually carry out useful work once they reach their destination. This also would mean that they might be radiation limited, since radiation shielding is going to take a large amount of the mass budget. The book "The Millennial Project" suggests that a water shield 5 metres deep is required for long term passive shielding from cosmic and solar radiation. Active shielding might be possible using superconducting magnets, electrostatic shields or other exotic technologies, but even there the mass and need for a power plant is going to cut into the mass budget. We can go on about landers, rovers, robots and so on.

Economically, outside of the development of miniaturized technology, there will also be some strange economic bubbles. I am presuming this drive needs to be lofted into space first before being activated (this is unclear from your description), so rocket launch services will be a boom industry. Other support industries like long range space communications will benefit, and of course there will be a speculative boom as banks and financial institutions as well as Fintech (crowdfunding, direct loaning like the lending club) and the stock market are attracted to this sector.

Politically there are two different scenarios which might happen.

Governments and populations might become "fat and happy" with the flood of new revenues coming in (the first waves of people heading out will most likely be asteroid miners looking for a quick return on their investment). People who stay at home and cut coupons and collect dividends will enjoy their lives and decide those crazy space people are ok so long as they stay in space. Asteroid miners don't get invited to too many parties.

The other way this could go is the governments of Earth send their bureaucrats to set rules and regulations, and their police and armed forces to enforce these rules. This is both due to greed (they want 100% of these revenues) and for self preservation. A 50 ton asteroid moving at interplanetary velocity is a weapon of mass destruction. The Chelyabinsk meteor was fairly small as these things go and delivered an estimate 500Kt of energy when it disintegrated in the upper atmosphere. A modern strategic nuclear weapon is estimated to deliver @ 300 Kt, to give you some comparison, so governments will be nervous about having this much energy available to potentially disgruntled people out in space.

The regulatory strangulation route seems likely unless this development is either so cheap that Ted and Earl can build it in their barn out of discarded parts, and launch directly into space from the barn. The internet is a good illustration of a disruptive technology that managed to spread fast enough to evade being smothered by government regulation for the first several decades of its existence. Your 50 ton limit makes an internet like revolution unlikely, since people will firstly be overly dependent on technological developments specific to miniaturized space systems to function, and secondly the size of the ships will be too small for large expeditions to set up colonies to develop independent powers and new polities throughout the Solar System to counter the governments of Earth.

  • $\begingroup$ 50,000 kg at maybe 500 km/s scares the daylights out of me. See my comments on the question. $\endgroup$
    – user
    Aug 21, 2016 at 15:25
  • $\begingroup$ A really nice answer, thank you - I imagine that in the early days there would be a lot of Ted and Earl panel vans floating around the solar system (complete with duck tape over places that might leak air) - sort of a space based Darwin Awards $\endgroup$
    – Michael B
    Aug 21, 2016 at 18:30
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    $\begingroup$ @MichaelKjörling : That will always be a problem with space travel, unless you make it exclusively stargate-based. Any spacecraft which could go to any interesting place in any practical amount of time would have enough kinetic energy to obliterate the ecosystem of an entire planet. $\endgroup$
    – vsz
    Aug 22, 2016 at 9:11
  • $\begingroup$ One thing I think you missed when thinking of the mass limit - 50 tonnes might not be enough to do much, but a bunch of these craft could convoy up and take the makings of a small colony to, say, Mars. Some of the craft could be dismantled for parts on arrival, or reconfigured as lifeboats to evacuate the whole colony in case of emergency. $\endgroup$ Aug 22, 2016 at 9:15
  • $\begingroup$ @vsz The Kzinti Lesson [CAUTION: TVTropes link] - "A reaction drive's efficiency as a weapon is in direct proportion to its efficiency as a drive." $\endgroup$ Aug 22, 2016 at 9:16


See Wikipedia article, especially this part:

Minerals and volatiles could be mined from an asteroid or spent comet then used in space for in-situ utilization (e.g. construction materials and rocket propellant) or taken back to Earth. These include gold, iridium, silver, osmium, palladium, platinum, rhenium, rhodium, ruthenium and tungsten for transport back to Earth; iron, cobalt, manganese, molybdenum, nickel, aluminium, and titanium for construction; water and oxygen to sustain astronauts; as well as hydrogen, ammonia, and oxygen for use as rocket propellant.

Due to the astronomically high costs of current space transportation, extraction techniques still being developed and lingering uncertainties about target selection, terrestrial mining is currently the only means of raw mineral acquisition today.

Emphasis mine. It looks like you are removing only real obstacle.


You can't pollute atmosphere on asteroids and moons there is none. If you can mine all you need, you can as well manufacture goods up there.


Above points would make some major reasons of pollution void, so Earth would get cleaner, quieter place to live.


Space is under no-one's jurisdiction. This would open all kinds of hell. Worker's rights? Not there. Police? None. As soon as new bases are opened, lawyers will start battles that wouldn't be settled for decades, because corporate needs would be quite opposite to what politicians need to appear to be doing. Pretty much any outcome you want might happen.

Spacers as sub-society

Not exactly, not at first. But space mining and industry would be lucrative. Some people would want or need to go for "just one more contract", stay "just a month longer", and some of them would be unable to go back to Earth. Families would get broken. Children born in space would be at strongest disadvantage. After some time of limited contact, Dirters and spacers would look at each others with distrust and lack of understanding. english will stay as common ground for communication, but we can expect Space english, just the way we have British and American one.


Lunar Module from Apollo missions was 15T. With crew, fuel and all. So your ship has a quite lot of margin. You don't need to send everything at once, you can send easy to assemble parts. Modern space stations are already made this way.

Of course high competition will lead to mass usage optimizations.

  • $\begingroup$ It's actually more reasonable to compare to the Apollo CSM/LM stack, because that was what had to be pushed by the booster. The LM had to contend with a number of issues that the other parts of the stack didn't need to worry about, not the least of which being to shed a lot of velocity for landing plus getting back to lunar orbital velocity later. Wikipedia gives the dry mass of the CSM stack as 11,900 kg, plus a dry mass for the LM of 4,284 kg (though the latter not directly; take fueled mass and subtract DPS propellant mass), for a dry CSM/LM stack mass of 16,184 kg. $\endgroup$
    – user
    Aug 21, 2016 at 15:32
  • $\begingroup$ On a free-return trajectory without required course corrections, the booster's final stage could inject such an unfueled CSM/LM stack into a translunar transfer orbit and the stack would have returned to Earth by gravitational slingshot around the Moon. A fully dry stack wouldn't have been survivable, though; no water, no electricity, no heat, no atmosphere, no crew... $\endgroup$
    – user
    Aug 21, 2016 at 15:34
  • $\begingroup$ @Michael but you need to land to mine or to deliver people to moon factory. And for pushing, we have this new fast drive. Anyway, a bit over 16T is still way under 50T allowed. $\endgroup$
    – Mołot
    Aug 21, 2016 at 15:36
  • $\begingroup$ Indeed, but that's the stuff you can actually carry on such a spacecraft. So if in this case the booster has an upper limit on 50,000 kg (and assuming this is magically independent of the target orbit), and the spacecraft that is needed to support the crew has a dry mass of 16,200 kg, that means you can allocate 33,800 kg to useful stuff, like oxygen, astronauts or any equipment the astronauts need for their sustenance or work. $\endgroup$
    – user
    Aug 21, 2016 at 15:41
  • $\begingroup$ And? You say there is quite a lot of mass to use. I say there is quite a lot of mass to use. What's the point of your comments? $\endgroup$
    – Mołot
    Aug 21, 2016 at 15:46

I don't think you need to look to far into our past to see what would happen. Colonization, and political "stuff" would follow almost the same pattern.

Of special interest may be Central America. Keep in mind that colonization efforts of "the new world" had similar limitations. A ship big enough to cross the ocean could only carry so much.

A lot of your "human" responses will be the same. Colonization, reform, separation. I think things these days will go along the lines of Canada or Mexico and not the lines of the USA (A more peaceful resolution to the independence issue).

We have not changed so much that those models no longer apply. We have hopefully learned from the mistakes of our past, but that doesn't mean that the same patterns won't arise.

I would recommend focusing on Naval law and historic colonization patterns. Also keep in mind, that there needs to be a "reason" to go. Look at Mars. We have the tech and the means right now to go to Mars. What we don't have is a reason for the hardship it would cause. If they found some super profitable material on Mars you can rest assured that they would stuff astronauts into tin cans and launch them at the planet. Same way we did with the moon. You engine makes this more viable, there is a bigger tin can, and it doesn't take as long but we still need a reason.


Others have provided great answers, but, in a nutshell, the economic, political and social changes would be very significant over the next 10 years.

We have a very recent and very pertinent example to guide us...the Internet! This technology is similar in importance to the intra-solar technology you are describing.

For all practical purposes, the Internet wasn't "on every desktop" until after 1994. Within the 10 years after 1994, planet Earth changed dramatically...socially, economically, politically. Earth was never the same because of the Internet. We are now, 22 years later, completely and hopelessly dependent upon the Internet.

In general, intra-solar travel would follow the same general pattern. Extra-Terra colonies would begin forming. New forms of trade would come to pass. We'd have access to new energy sources. Scientific opportunities would greatly increase. Ultimately, I think it would have significantly more impact than the advent of the Internet.

We...the bacteria...would have easy access to a much larger and richer petri dish!


If a spacecraft with a maximum mass of 50 tons can take off from the back streets of Birmingham and fly to Neptune and come back it must be able to generate a rate of acceleration in excess of one g. This will enable it to travel anywhere in the solar system in days or up to weeks. The spaceship would take about a week to travel to Neptune at 1 g, and another week for the return trip.

This does suggest that the spaceship will reach a maximum velocity of one percent of lightspeed. To think people were worried about a fifty ton missile moving at 500 km/s, that's peanuts compared to the impact this baby would make.

It's hard to imagine a spacecraft drive power plant with an upper limit to its mass of fifty tons if it can generate an acceleration of 1 g plus. This takes us into realm of Aristotlean physics and that's only a more sophisticated version of magical thinking. The rest of this answer will assume, irrespective of the space drive's power plant, that Newtonian physics applies.

This will mean the mass limit is mirage, however, if the true limit of the space drive's power plant is the volume encompassed by the drive field then this argument collapses. Considering the possibilities of this kind of space drive in relation to Newtonian physics has some interesting results.

A larger version of this vehicle, with a payload of five hundred tons, could be supplied by a fleet of space trucks plying the Earth surface to orbit run, and launched with a modest acceleration of one-tenth g. This larger vessel would be slower and hopefully surer, but would the advantage of a heavier payload. This will make expansion into the solar system an easier proposition.

A further step of allowing for lower acceleration and a higher payload would be to go down to an acceleration of one-thousandth g or one centimetre per second squared. The payload is now fifty thousand tons and the solar system is our oyster!

While racketing around the solar system in a single fifty tonner spaceship might be fun, there's not too much they can do. However, if you start flying fleets of them travelling in squadrons or running regular routes so lots of spaceships are travelling to, say, Neptune in large numbers and at regular intervals. Many of these craft won't need to be manned. Now by allowing bigger, heavier and slower rates of acceleration this space drive will make human expansion into interplanetary space both rapid and easy.


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