I have been working on a hard Sci-Fi narrative of a first-time human colonization scenario on an interstellar star system like Alpha-Centauri.

My narrative though uses NO FTL drives or other fictional warp technology and instead focuses on realistic interstellar travel. The ship I thought of can travel at 70% of light speed. It is accelerated using photon laser propulsion on Earth and gets to Alpha Centauri in 6 years. It is powered by a hybrid of fusion and antimatter engines and uses it to decelerate. The ship can carry up to 250 metric tons. It takes place in the year 2200.

My ship

In its cargo section, it carries:

  • Parts for an "In-Situ Stereolitography Plant" which is capable of 3D-printing anything once it is installed on the colony.
  • Medicines and electronic parts like micro- and nanoprocessors and other circuitry elements that cannot be produced locally on site
  • Food and plants from Earth for consumption and future farming on the planet
  • Parts for modular habitats
  • Some parts for drones and small cargo vehicles.

I got all that down but then I started to think of building a bucket-wheel excavator on site, then suddenly remembered they are powered externally. I finally came to wonder what kind of reliable power source is the best for such a first-time human departure.

The planet is continental just like Earth with plants, water and varying weather. Both on a sci-fi and realistic perspective, what stable and sustainable form of power do you think is BEST for such a scenario?

I was thinking of bringing on the ship either parts for a:

  1. A small modular nuclear (fission) reactor
  2. A fusion reactor
  3. Geothermal plant
  4. Solar energy

What benefits does one bring from the other? I was thinking fusion reactors but thought bringing parts for a small Tokamak that can provide enough power for 300 people would be heavy to bring - or is it? If so, would there be changes needed on what types of cargo should be brought into the ship?

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    $\begingroup$ 70% lightspeed won't get it there in 6 years, because it needs to accelerate / decelerate (unless there would be something like 20 g). $\endgroup$
    – Mithoron
    Apr 25, 2022 at 0:22
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    $\begingroup$ How can a star system be "interstellar"? $\endgroup$
    – Daron
    Apr 25, 2022 at 12:44
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    $\begingroup$ You'll need power on the ship during the journey, so whatever power source you use for that can be repurposed at the destination. That rules out solar and geothermal, since those obviously won't work on a spaceship in interstellar space. $\endgroup$
    – N. Virgo
    Apr 25, 2022 at 12:52
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    $\begingroup$ "The ship I thought of" uh, that's very clearly lifted directly from Avatar, specs, appearance and all. $\endgroup$ Apr 25, 2022 at 12:54
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    $\begingroup$ At 250 tonnes payload, that is not a colony ship. That's a large scientific exploration team/scout. Life support is about 1tonne/person. plus manufacturing equipment, plus food, water, oxygen. I would say 25 people would be max crew and that would be on the very high end. For comparison: Saturn V moon payload 40 tonnes . $\endgroup$ Apr 25, 2022 at 21:37

14 Answers 14


Since it is "Hard Sci Fi" you should not call a planet orbiting another star an "interstellar planet", because that is obviously not what it is. I thought by "interstellar planet" you mean a "rogue planet", a planet sized body that does not orbit a star. How to power a colony on such an object would be an interesting question.

I want to point out the following: To decelerate 250 tons from 70% lightspeed you need well over 5 Zetajoules - and that assumes 100% efficiency and does not even count reaction mass. That is 10 times more energy than humanity consumes in one year.

Powering a colony of 300 people is peanuts compared to that. Whatever powered your ship can power your colony.

If the energy source for the trip was antimatter, then the easiest thing seems to be to simply pack in a bit more antimatter as power source for your colony. It would hardly make any difference in terms of transport costs. I would not know how to run an antimatter power plant, but obviously the people in your story know.

And in case the power source of your trip was a fusion reactor, you already have that, too.

If the planet is like Earth, then solar energy, wind energy, geothermal energy all seem like good options, depending on your location. Since payload is an issue, I recommend solar energy. It has the advantage that you may have been able to bring thin film solar modules with you - they do not weigh much.

Farming terrestrial food on a planet that already has life could prove difficult, dangerous and is also morally questionable. Introducing a completely different form of life into an ecosystem is probably extremely disruptive. I really hope for the future that there is a law against what your settlers are doing.

  • $\begingroup$ As the OP stated, the ship is accelerated using a laser sail. It is unlikely that a useful laser flux could be collected at the target star, and even if there were you'd almost certainly get more energy by using the same collectors aimed at the star the destination planet is orbiting. $\endgroup$ Apr 25, 2022 at 12:42
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    $\begingroup$ Thanks, I edited my answer. As the OP stated he uses a "fusion/antimatter hybrid" to decelerate which requires as much power as acceleration. $\endgroup$
    – Avun Jahei
    Apr 25, 2022 at 16:39
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    $\begingroup$ I think they need antimatter because of the rocket equation. At the beginning of your deceleration process you need to decelerate the entire fuel stock as well. Fusion transform 'only' around 4% of mass into energy. To slow down from 70% of light speed to zero would require several orders of magnitute more fuel than cargo. $\endgroup$
    – quarague
    Apr 26, 2022 at 6:48


solar flex sheet


A fusion reactor and a fission reactor constitute all eggs in one basket. If something breaks you cannot get spare parts and you are sunk.

Solar is good because you can bring a metric boatload of the 2200 version of these flexible sheets. If a bantha sits on one that is ok because you have more.


The best one did not make your list: hydroelectric. You can bring motors and use them as generators, turned by a water wheel. You can bring bearings for the wheel and if you maintain them they will last a long time. You can make the wheel and the dam from local materials. You can have a lot of wheels. Water wheels do not need to be epic. A stream and a pond is all you need.

A place with moving water is a good place for people to live. If you are short on materials, waterwheels are useful without electricity. They can and once were be used to power machines like looms and mills directly.

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    $\begingroup$ Nice thing about the hydro-electric solution is that the same technology also works for wind-turbines. So if running-water is a bit scarce, you still have options. $\endgroup$
    – Ruadhan
    Apr 25, 2022 at 15:53
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    $\begingroup$ If you have reliable fusion power you're probably better electrolysing that water and feeding it into your fusion plant. $\endgroup$ Apr 25, 2022 at 17:26
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    $\begingroup$ @SeanBoddy, you're making assumptions about hydropower. For example, run of the river turbines don't need large dams. And consider something like Niagara Falls: the hydroelectric facilities use the natural topography so they don't need to create a large reservoir, and the total volume of water downstream is the same so there's no concern about changes in the water regime at the mouth of the river. $\endgroup$ Apr 25, 2022 at 19:32
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    $\begingroup$ @SeanBoddy: Don't have to worry about ecological disasters if you don't care about the local ecology! taps forehead $\endgroup$
    – Joe Bloggs
    Apr 26, 2022 at 10:55
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    $\begingroup$ You can have hydroelectric without damming water flows. A simple paddle wheel in a water flow does not create ecological disaster. $\endgroup$
    – Arluin
    Apr 26, 2022 at 19:05

When thinking about hard science fiction, you are going to be working with technologies we do not currently have. You will have limited intuition on how they work.

I find it useful to fall back on mathematics. In this case, the Kardashev scale.

You have some technology (which you have vaguely described as a combination of a light sail and an antimatter drive) capable of accelerating a ship with 300 people on it to 0.7c and back down again. What it the K-scale of the civilization? Of the ship?

If we bound the acceleration to 1 G with a 500 tonne ship (extremely light-weight materials!) that is 5 MN of force. Getting up to speed requires 250+ days (Newtonian approximation isn't that bad at 0.7c), and kinetic energy at cruising speed is 500 tonnes * c^2(1 / sqrt(1/2) - 1), or about 2 * 10^22 Joules. Producing this over 250 days requires 10^15 Watts, or a Kardashev-scale 0.9 civilization (ignoring waste products).

By your design, this level of power output must be sustained on the ship for a year to stop in the target system. During launch, you are going to need this level of power output in the home system as well.

A K-0.9 scale civilization power output is using almost as much power as the entire sun deposits on the planet Earth.

When arriving at your destination, worrying about the power requirements for a 300 person colony will only be a concern if that 300 person colony expects to be able to individually build orbital beanstalks.

On average, a US citizen's standard of living is sustained by under 10^5 Watts (this includes everything from mining ores, heating homes, transport, farming, etc). If we budget 10^5.5 Watts per citizen in your colony of 300, this gives your colony a power budget of 10^8 Watts, which is 10000000x less than the drive system of your starship.

Imagine you have a modern 747 Jet. Its power requirements are 10^8 Watts in flight. Suppose we asked "how are we going to power a phone charger at the destination". A 5V 2A phone charger is 10W, which is 10^7 less than the power requirements of the plane.

Sustaining that colony is roughly as hard, compared to travel power use, as running a single phone charger compared to fueling a 747 airplane and flying it around for a few years.

It isn't a serious problem.

So, how would I imagine it would go?

First, there would already be survey robots in-system. They'd have arrived long before hand on cheaper ships. They have found high-metal asteroids and have converted them into factories, which in turns have harvested others, producing a space-based industrial base. Heavy metals are far more common in asteroids than in planet crust (as on planets, Heavy metals sink to the core), so nuclear reactors are cheap and easy to build.

These then dropped colonies to the planet below, again with robots, ensuring there are multiple redundant places for humans to live (no point in sending people in a huge budget ship just to die).

Before your ship is launched, a series of slower reflectors (light sails without cargo) are sent ahead. To decelerate, your ship fires its photon drive at them, which bounces the light back to the ships light sail, ideally more than once. Each bounce improves the efficiency of the drive on your craft.

Energy (for individual use) isn't the hard part. You have small nuclear reactors scattered around the system doing tasks and planet that produce electricity for anything much short of transforming levels of requirements, and new ones produced as needed.

You'll start building bio reactors to produce a biosphere compatible with human life. If you look at the history of the Earth biosphere, only a relatively small fraction of it was hospitable to humanity, and that is on the planet of our birth. I mean, even something as ubiquitous as Trees has been around for single-digit percentages.

If there is a biosphere there, mass producing Earth-based bacteria that can consume their biosphere and replace it with a terrestrial one, get the atmospheric chemistry somewhat similar to modern Earth, produce the terratonnes of "soil" bioproduct required for multicellular life, use machinery to process rock into feedstock for soil factories, etc.

We'd have practiced this process on Mars, possibly in failed colonies there (or a continuing terraforming project); converting raw rock into soil would be an art. Building robots that make more robots in the home asteroid belt and as part of the Mars and Titan projects. So this remote terraforming of the planet around another star wouldn't be novel; the lack of connection back to the Sol industrial base is the interesting bit.

The new colonists would show up to pre-built settlements, maybe still domed. They'd know what the experience would be like thanks to the Mars project workers. As you wouldn't be sending humans there unless you wanted there to be more humans there, factories to produce more citizens would be a requirement: hospitals, cloning pods, germline printers, schools, and tools to allow a relatively small number of humans to grow, nurture and educate exponentially more citizens.

By 2200 it is also plausible that we'd be able to upload and download consciousness. Either living outside of a biological body is horrible, or the biological humans are akin to pets; we'll assume the first (as "biological as pets" is a very different story). So you'll have copies of people's brains in data storage, and printing new bodies and downloading the data-brains into those new bodies is something this colony will be doing. This will allow it to get more expertise than an initial seed of 300 individuals would allow.

Terraforming of the planet will probably be the largest energy expenditure for the lifetime of the people sent over interstellar space. But only a fraction of the people will be involved in it directly. Each generation of people will be a mixture of printed people (some sent along in the ship, some broadcast from Earth, some from backups of people who have died on this world of danger or old age) and newly born humans; possibly the draw of the new system is that there is room to have fresh, newly born babies.

Power for personal use will come from nuclear batteries (being the lowest maintenance, longest term option). Power for the terraforming efforts will be via huge microwave stations, beaming power from orbit. Use of solar panels and hydro dams on the planet will be limited, as part of terraforming is sculpting; resurfacing the planet. Using huge chunks of it to generate power, when you are busy rebuilding it, would get in the way.

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    $\begingroup$ Nice! Breaks firmly away from engrained golden age sci-fi tropes (still the norm in mass entertainment) $\endgroup$
    – Spike0xff
    Apr 26, 2022 at 22:18

Fusion and Antimatter

It is powered by a hybrid of fusion and antimatter engines and uses it to decelerate.

This is a no brainer. The ship's engine is the colony's starting power source. It carries an extra 200g of antimatter fuel, more than enough for the first 100 years of colonisation.

When they reach the new planet, the colonists zip down to the surface in their pods. The ship stays in orbit. It has a sensitive antimatter engine that will not survive landing. At best it breaks. At worst it goes boom.

Instead the ship redirects antimatter power to the deflector dish. . .

enter image description here

. . . and shoots a laser beam to the surface. The same sort of beam pushed it all the way here.

The colonists build a Beam Catcher to catch the beam and use it to power their tricorders and sonic showers and other doodads. They also brought some batteries in case the weather changes. This gives them a reliable if inefficient power source.

The Beam catcher works uses the same principles as solar panels. Once they perfect the beam catcher they start making solar panels.

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    $\begingroup$ I mostly like this answer, but personally think it would be better to design the whole ship to land. Leaving any part of your colony ship in orbit is a huge waste of resources. When you look at colonial America for example, many colony ships were designed with the intention of being cannibalized for parts. The ballast was often used to pave thier roads, the hull disassembled to make quick, basic housing, etc. So in this scenario, simply landing and using the ship's reactor for all of your initial power needs would make lots of since. $\endgroup$
    – Nosajimiki
    Apr 25, 2022 at 14:09
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    $\begingroup$ @Nosajimiki Let's not forget the cost of landing. Every part of the craft you intend to land means extra landing equipment and fuel to carry on the whole trip. Want to land the whole thing? Then you need to bring 50% more mass so it does not go splat. Maybe we are better off bringing the same amount of iron ore and just dropping it. That in mind, the ideal amount of the ship to land will be somewhere between none and all of it. I'm thinking the reactor remains in space since it's a sensitive piece of machinery and hard to land without breaking. $\endgroup$
    – Daron
    Apr 25, 2022 at 15:59
  • $\begingroup$ Upvoting with a few caveats. 1 using a laser to transmit power is the worst choice. You'll lose so much in transmission to the atmosphere. Instead use microwave power transmission. Second. yes the onboard power generation (antimatter reactors?) at first would probably be the first choice but later dedicated orbital solar arrays would be preferred. Less expensive less massive, easier to maintain. And would free the ship up for other uses. $\endgroup$
    – Gillgamesh
    Dec 12, 2022 at 14:09

All of the above

Because the best way to get your energy is from a healthy mix of different sources. That makes your grid more resilient to failures and to the ebbs and flows of demand.

Okay, well, that's a cop out answer, but where do you start?

The best option for your Colony Starter Kit is probably some kind of nuclear reactor. It's a good way to get a start because it provides a lot of power, and we put nuclear reactors in things like submarines so it's not much of a leap to imagine a portable nuclear reactor. The main downside here is it will require fuel. That fuel might be hard to produce and might have to be imported at great cost, and that obviously means you are critically dependent. So you should seek to diversify as soon as possible.

Simple water turbines will be quite easy to set up, and have been used since time immemorial. You get mechanical energy from it, which you can then convert in electricity, or not. Large hydroelectric dams on the other hand are going to require a lot of work, but give you a lot of power. The upside is there's no fuel and it will always work as long as the water flows, which is what water tends to do all the time. But you are limited to the rivers you have.

More modern but still quite simple, you have concentrated solar power. It's mirrors focusing solar energy into a point to heat it. It gives you heat, which you can use directly, or convert to electricity.

Solar panels and wind turbines should also be fairly easy to set up and don't require fuel. The upside here is it will always work. As long as there's enough sunlight and wind. The downside here is manufacturing replacement. Solar panels in particular require you to mine and refine the components, while the complexity of wind turbine is mostly in manufacturing the blades.

Fossil fuel plants have a similar problem to nuclear with the fuel. Oil, gas or coal have to be mined, refined, stored, transported. That's quite an infrastructure, but it's also probably a lot easier to produce locally than deuterium for fusion. Biomass would be an even easier thing to burn to get energy, unless you have a barren planet.

Geothermal energy is a great source of heat, which can be used directly and is electricity you don't have to generate. It can be used as the scale of a single home for heating and cooling without much digging (as an alternative, air-source heat pumps will also be helpful here). To make electricity from it though, you will have to drill. Drilling has been known to cause earthquakes and other issues, but with a bit of scifi maybe you can solve that. Still, it's not trivial but the major advantage of geothermal (whether a small ground-source heat pump or big plant) is it works all year-round, 24/7.

And then some storage

In an electrical grid, you have to use 100% of the energy you produce, no exception. At least that's how we do things in the present. In fact, producing more than you use is probably worse than trying to use more than you produce. I mentioned the ebbs and flows of demand above because in reality we're rarely matching demand and production perfectly. This is where you need storage.

Storage on Earth is mainly handled with gravity. The principle is simple: use excess energy to lift something, then later use the thing going down to make some electricity. Typically, the thing is water, and controlling the flow of water up and down is one of the advantages of hydroelectricity, and this makes for a lot of energy storage.

Another way to store energy is spinning. Now that's a good trick! The idea here is to cause something really heavy to spin by using excess energy. Once it's up to speed, it takes very little energy to maintain, until you reclaim that energy later when you need it. A single flywheel, as these things are known, doesn't store as much energy as a lake, that's why you use a lot of them. Flywheels can be scaled down for portable applications (e.g. KERS), which is something you can't do with a lake.

Then you have what-you-think-when-you-think-of-batteries, the rechargeable battery. Hopefully I don't need to explain that. But beyond dedicated storage facilities, you could imagine using devices plugged into the grid to store and retrieve energy. Like, if you had millions of electric vehicles all connected at the same time for instance.

Same concept but different energy, the thermal battery. Here, the battery doesn't input or output electricity but heat (which can then be converted into electricity). Thermal batteries are a must for concentrated solar plants if you'd like to keep it going all night long. Molten-salt batteries are commonly used there, I'm sure there are other similar technologies.

In another form of chemical storage, you can use excess energy to make fuel, like hydrogen through electrolysis. Then you get free fuel, which is always nice.

  • $\begingroup$ +1 for geothermal. Its a nice idea that works regardless of weather, atmosphere, distance from the sun, availability of current or historic biomass, etc, and doesn't need a hypertechnological manufacturing base to achieve. $\endgroup$ Apr 25, 2022 at 13:06
  • $\begingroup$ spinning, presumably, rather than spining $\endgroup$ Apr 26, 2022 at 15:45

Beamed Power and Batteries

Your orbiting interstellar spaceship must have access to it's own power generating facilities. Whatever reactor system it uses can be used to power a large microwave generator, that focuses a beam of microwaves at an area on the outskirts of your colony.

In this area (probably a few square kilometres across), a large number of rectennas are built. These are simple to construct, and really only consist of some long coils of wire strung out on poles, connected up to some control electronics and a battery bank. The rectenna farm converts the microwaves into electrical current. When the Spaceship is orbiting over the horizon, it beams power down to run the colony and charge the batteries. When the spaceship is below the horizon, the colony runs off the battery bank.

This system has the advantage of using pre-exsisting hardware, and minimal infrastructure for the colonists to set up. It is enough to get them started and set up with their own manufacturing infrastructure.

As the colony grows, they will want to diversify into constructing their own sources. These may include solar power, hydroelectric,wind power, fossil fuels or geothermal, depending upon what resources and geology they can find on their new home.

At a later point, more advanced power sources such as fission or fusion reactors may become viable. They are not initially likely to be viable until the colony has constructed significantly more infrastructure, has enough trained people to operate them, and enough manufacturing capability to produce spare parts and manufacture fuel.



Your ship has a fusion reactor. It's pretty easy to get deuterium and tritium from local sources like water and lithium, which are both very common. Just make a big battery and stick it in any vehicle you want to use. The range won't be incredible, but for making a local colony it should be fine.

Batteries can be made from a huge variety of materials, and they're pretty easy to swap in and out. Your ship will probably come with a ton or so of batteries in a variety of forms to power equipment, and you can build more batteries. When you want to extend the range you can set up solar powered waystations with locally made batteries.

  • $\begingroup$ The ship has fusion engines, but that's not the same as having a convenient power supply. Consider the difficulties in tapping some of the gigawatts of power developed by a conventional rocket motor, for example. $\endgroup$ Apr 25, 2022 at 12:50
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    $\begingroup$ It would actually be pretty easy to capture the power of a rocket motor, since it's just a burnable fuel you could remove and burn for power. The basic design of a nuclear reactor is just a nuclear reaction that heats a solid or a liquid, which then is converted into whatever power. It would be a pretty dumb ship design that didn't have a way to tap into this for power. $\endgroup$
    – Nepene Nep
    Apr 25, 2022 at 13:04
  • $\begingroup$ Yes, you can ignore my point if you like. $\endgroup$ Apr 25, 2022 at 13:08
  • $\begingroup$ @StarfishPrime apart from being incredibly oversized for power levels actually required, the engines are also apparently reliant on antimatter for their function. Just having sufficient quantities of that in proximity to the colony might be an unacceptable risk. $\endgroup$ Apr 25, 2022 at 18:38
  • $\begingroup$ @NepeneNep it's hard enough to build an engine that's useful for interstellar travel. Building it to also provide a minuscule fraction of its normal power output when not propelling the spacecraft could very easily be an unnecessary complication. The two things have very, very different requirements and it is entirely reasonable for them to be filled by different pieces of hardware, even if the basic principles are the same. $\endgroup$ Apr 25, 2022 at 18:41

Nearer-term, beamed power from the orbiting spaceship(s) should be plenty. Longer term, it might make sense to build orbiting solar collectors that can then forward their output to the ground-link power beam already constructed. As the colony grows, more solar collectors and ground-link power beams can be constructed to power those sites as well.

Because the solar collectors are in orbit, at least some of them will always be in direct sunshine. This will provide the needed reliability.


Part One: Why Fusion Would be the Main Power Source.

The main power source should be fusion, the best power source for an industrial civilization.

Fusion power works equally well wherever it is located on the surface of a planet, or wherever it is located in interstellar space, unlike any other power source except for other forms of atomic energy.

Fission uses rather rare elements and isotopes instead of the much more common elements and isotopes which can be fusioned for energy. The earliest fusion generaters will use isotopes of hyrogen, the most common element in the universe.

A fission chain reaction can possibly get out of control, resulting in a messy reactor meltdown,and it has happeneda few times. Despite many science fiction stories depicting fusion power plants running out of control and exploding, it would take a very evil genius indeed to design a fusion power plant that could explode. Fusion needs constant application of power to occur, and the power imput can be precisely controlled and shut off with the turn of a switch, instantly ending the fusion process. The machines which produce the fusion are not designed to produce an explosion and cannot be forced to produce explosive amounts of fusion.

Fusion is the closest thing to an all around perfect power source. If a society has developed practical fusion power generation using fusion power should be their first power generation choice for almost every imaginable situation.

Part two: Redundent Power Sources.

It seems obvious that the colony would want redundant power sources. If their power fails, they will be literally light years of distance and even more years of travel time from any possible outside assistance.

If the main body of the interstellar vehicle remains in orbit a small part of its fusion power plant could be run, and the energy it generates - a tiny fraciton of the total propulsion energy - beamed down to receivers at the colony site.

If the main vehicle lands, or if smaller landing craft are used that make any sort of powered landings, those landings are likely to be powered by fusion. The energy energy generated by fusion could power rockets, or jets, or magnetohydrodynamic drive, or anti gravity drive, or whatever. But unless fusion generators would be far too large for the craft that land, fusion would be the obvious choice to generate the power for a powered landing.

So once a landing craft is no longer needed to land the colony, they can hook up its power source by a cable to the main power distribution unit of the colony. If the landing vehicle(s) use rockets, the powerful rocket exhausts may scorch the land for kilometers and miles around, so the colony site might be kilometers or miles from the landing site and a long cable may be needed.

And an entire fusion genrator, or the parts for one, can be brought down and set up at the colony.

And the first thing that the 3-D printer of the colonly will make will presumably be all the parts to assemble a second 3-D printer, and the second thing it will make will be all the parts for a second fusion power generator, and the third thing it will make should be the parts for a third 3-D prince, and the fouth thing it will make should be the parts for a third fusion power generator, and so on. The colonists will want to have all the necessary parts for several spare fusion power generatiors and 3-D printers before they start making less vital stuff.

And of course fusion power will be supplimented by other sources. All of the buildings' outer walls should be covered with thin film solar panals for auxillary power generation. And many thin film solar panels will be set up apart from the buildings, and thin film mirrors to reflect additional light onto them.

Of course the solar power panels will be rather flimsey and could be blowndown in high winds. So the colonists would also build some sort of wind turbines capable of powering the colony if some disaster disables both the fusion power plant and the solar panals.

But the wind turbines could be damaged or destroyed by really violent winds or alien-planet-quakes. So the colonists should also dig deep, deep wells for alien-planet-thermal power generation, for example.

And the colonists should continued to live in their landing vehicle(s) until many redundant power sources are established and then they can start assembling prefabricated houses and other buildings and other ewquipment.

And of course the colonists would want to build power storage in case all the redundent power sources fail at the same time. So they will build water towers and use power to pump water up into the water towers so it can be used for hydroelectric power if necessary. And they might build giant flywheels and spin them extremely fast so that they generate power by braking the flywheels.

And they might use some of their generated energy to make chemical fuels and store those chemeical fuels in case of need.

For example, a method has been developed to use sunlight to produce hydrogen peroxide from seawater, which can then be used to produce more energy in fuel cells than was needed to make the hydrogen peroxide.


Part Three: A Frame Challenge.

You write:

Food and plants from Earth for consumption and future farming on the planet

And I wonder if you imagine that they would plant plants in the unearthly earth or soil of that alien planet to grow.

Plants and seeds imported from Earth need Earthlike conditions to grow in the unearthly earth of an alien planet.

As we all know, photosynthetic plants use sunlight to break up carbon dioxide in the air to make complex food chemicals, and release oxygen into the air, a process which created Earth's oxygen rich atmosphere. But plants also need oxygen in the air for their metabolisms havig adapted to use oxygenover hundeds of millions of years, so Earthly plants couldn't survive in a pure carbon dioxide atmosphere. Plants also need some nitrogen in the atmosphere.

What sort of atmosphere would the colonists need on their new planet if they don't have to wear spacesuits every time they go outside?

Habitable Planets for Man, 1964, by Stephen H. Dole, discusses human atmospheric requirements on pages 13 to 19.


To summarize, then, the atmosphere of a habitable planet must contain oxygen with an inspired partial pressure between 60 and 400 millimeters of mercury and carbon dioxide with a partial pressure roughly between 0.05 and 7 millimeters of Mercury. In addition, the partial pressures of the inert gases must be below certain specified limits andothertoxic gases must not be present in more than trace amounts. Some nitrogen must be present so that nitrogen in combined form can find its way into plants.

And the next section, on water, mentions that some water vapor in the atmosphere is necessary for human health.

So any food plants humans would plant on an alien planet would need an atmosphere similar to one which humans would require to breath. Of course different Earth plants and animals have different upper and/or lower limits to the amounts of various gases they can tolerate, but the ranges of all Earthly food plants overlap with that of humans quite extensively.

And where did the oxygen in Earth's atmosphere come from? From photosynthetic plants. So either the colonists will have to live in orbit, or sealed buildings, and wear spacesuits on the surface of the planet, for meany generations, possibly for milllennia while they terraform the planet, giving it a breathable atmosphere - or else they will find a planet which already has a breathable atmosphere produced by native photosynthasizing plants.

So are the colonists going to just plant Earth plants in the unearthly soil of the alien planet to complete with the alien plants?

Some people would have problems with that.

Maybe alien plants adapted to condiditons on the alien planet will constantly out compete for resources with Earth plants, &bthe colonist will be unable to grow crops in the alien soil,band will starve.

Maybe the two sets of lifeforms will be mutually edible, and Earth germs will infect alien plants and alien germs will infect Earth plants.

Mybe the two sets of lifeforms will be mutually poisonous, and the settlers will have to exterminate all native life within a region before introducing Earth lifeforms.

And those three possibilities are not good ones.

So maybe the settlers will put all their farms inside buildings and grow hydroponic or aeroponic crops in those buildings.

Or maybe the settlers will make a number of 3-D pinters to make sythasized food out of various elements and compounds in storage.

And some people might think that if they do that, why settle on the planet at all? Why not just build artifical space habitats to live in? And that is a question that you might want to think about for this story, or for future stories you mgiht write.


There are a couple of issues for power and there are points you need to consider. First, do these travellers know the state of the planet very well? If they do and if it allows majority of it could be from solar power. Solar cells are light, long lived, and with the projected improvements in efficiency, it could reach to an incredible level by 2200. Solar by itself will not be sufficient as you would need power source for nights. If possible a small RTG type reactor can be used for life support and mining will take place during the days.

If the planet is known to house large bodies of water, hydroelectric could also be viable. However, hydroelectric will be heavy, requires large generators. It should also be supported until necessary infrastructure is built. I would think this will be a secondary project rather than initial way of generating power.

However, if nothing else is known about the planet, you need to pack a compact fusion plant.

Some answers talk about descellaring once you got there. This might be assisted by gravity assist. If you could get close to the star without burning, you can perform descellaration burn there, which will amplify the result greatly. Also you could take a longer route that will take relative speed difference of star systems to reduce the amount of energy that is necessary to slow down. However, you will not be able to reach there in 7 years in this case. More like 10 years or so.


Fusion Power

Geothermal, solar, hydro or similar power sources are nice in theory, but they restrict your colonization choices. Only a subset of locations on a planet are optimal for those power plants, and do you want to constrain the colonizers that way? Let them choose based on other resources, weather, and what they find.

Fission requires fuel, and fuel requires mining. You run into a bootstrap problem. You can put it off by bringing several years of fuel with you easily enough, but it's still a problem looming over the colony until resolved.

Fusion has one major down side: It's at a higher technology level than the other options we've discussed. But you've already decided to accept fusion as a solved technology, because your ship is fusion powered. And fusion has the further advantage that fuel is everywhere; deuterium can be concentrated from any natural water, and a colony without access to water has bigger problems than fuel.

You can look at what size tokamak you would need, but there's an easier option: Bring down one of the power plants from the ship under a big parachute. The day-to-day needs of a colony are much, much lower than the needs of a ship under propulsion, so you have plenty of power there. And you've already paid the weight cost to ship it across the galaxy.

Now, a ship's thruster is not a conventional power plant. You're not going to plug your toaster oven into it and get a nice morning waffle. A fusion thruster does one thing -- it makes a propellent very, very hot. The ship power plants probably do have some electrical output (maybe something low efficiency but super robust like thermoelectrics) to power the rest of the ship systems, but the majority of their power is going to thrust.

This is where good old frontier ingenuity comes in. How do you turn a thruster into an electric power station cheaply and with locally available materials (though not necessarily efficiently or safely)? Print a steam turbine and run the thrust exhaust through that.

  • $\begingroup$ I suspect any such colony would already know how to transfer its ship's fusion plant into dirt-side power, that it would be an integral part of their plan. It would not make any sense to haul such a thing across the stars and then stop using it. Now, if the story is the usual desperate survival-against-the-odds saga something may have gone wrong with that plan and now your colony has to come up with something else. $\endgroup$ Apr 25, 2022 at 6:48


If your world has any native plant life, and a breathable atmosphere, then it is a safe bet that you can burn some of it, properly prepared (cut and dried), to produce basic power.

This is your bedrock power source as there are likely several million times more available material than you will need for your small colony starting out.

You can scale up from wood to coal by calcinating wood. Despite the weird name it is a simple process, burn a large pile of wood, with the outside of the pile covered in mud to keep air out. This produces coal, which was our energy staple until the mid 1900s.

You may bring a fission plant from home. But, unless there are fissionables on your colony world easily available in great quantity (and for some scale, until the early 1900s the world supply of fissionables was less than a thimbleful). If it isn’t available, that initial fission plant will continue producing a fixed, but steadily slightly decreasing output until it breaks down. Which may be up to a century. But it is only one power plant, and if it’s driving one tractor, it is not powering anything else.

Mineral fuel (oil) may be available. There is a growing body of research that there are non-biological paths to a rock body producing oil reserves. This is a portable (more so than coal and steam by at least an order of magnitude), and requires no special elements that may not exist on your planet.

Fusion is out for a starter colony because, unless by happy accident the planet is rich in rare hydrogen isotopes, you will require tremendous already built infrastructure to harvest and refine the small amount for use in industry. That would probably be too big a bet for a colony planner to use as Plan A, but some enrichment parts might be sent so that it can be done as a Plan B or Plan C.

  • 1
    $\begingroup$ Calcinating wood is how you make charcoal. Coal is a fossil fuel and is a distinctly different substance. Otherwise, I agree with this answer. Hydrocarbons are generally going to be the simplest power source for a small but modernized colony to exploit. $\endgroup$
    – Nosajimiki
    Apr 25, 2022 at 17:06

I've seen two ideas floating around as potential near-future technologies which could work quite well.

  1. Radioactive waste batteries. I've heard some musing over the idea of forging radioactive waste into diamonds and then building shielding and tech around them to generate an electrical current from their slight radio-active output. If it works (and the shielding doesn't give) you have a black box that will output a small amount of electricity for thousands of years.

  2. Drill into the planet's core. There are currently a few companies taking another shot at this tech. I'm assuming your colonists are heading to a planet with a magnetic field -> which implies it has a molten core. If you can drill far enough down you get a permanent source of heat for running generators. Its just a question of whether your future tech is up to the job of digging that deep and resisting the heat/stress.


If all else fails, direct power from wind and/or water mills. You can add to that by animal/human power, if needed.

Mechanical power does not need to be fed by electricity, it has been done without for many centuries on Earth, it will work on other planets as well.

Not as high tech as getting to the planet, but more reliable than high tech options which they can not produce or replace once broken.


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