User:Hephaestix/Project Hephaistos

= Project Hephaistos =

Hḗphaistos was the Greek god of metalworking, craftsmen, artisans, and fire. In Greek mythology, Hephaestus was cast off Mount Olympus and lived in exile underneath Mount Etna, later to return to Olympus. He is described as being lame as the result of a congenital impairment, but a craftsman who makes up for his impairment by devicing genial designs.

In this Book we will discuss in broad strokes the ideas and designs of "Project Hephaistos", an interstellar starship. Just like its namesake this ship will suffer from being lame and will have to make up for its slowness by utilizing all kinds of crafts.

Why should we reach for the stars?
A common question asked when pondering interstellar travel, is why try this in the first place? After all, there is no reasonable expectation of any kind of trade with distant colonies, a mission that under enormous costs at the very edge of our abilities would bring a handful of humans to another star system would not alleviate any population problems on earth, and all the resources committed to this singular project could surely be used back at home?

There are some arguments for a mission like it:
 * Survival of species-level extinction events
 * knowledge only obtainable by spreading throughout the galaxy
 * advancements in technologies necessary for this mission would benefit broader society

Limits of imagination
If we try to envision a realistic future mission to the stars we will always have to start with the technologies we currently have at our disposal. We might speculate about enhancing performance characteristics by some factor or to engineer proven principles on a much larger scale. However if we start speculating about technologies not even in its infancy yet we would soon enter the realm of fentasy. Let's have a look at three examples: Antimatter, Cryosleep, Alcubiere-Warpdrive.

For an interstellar mission the Alcubierre-Warpdrive looks most promising: afterall to warp spacetime around the ship would free us from the shackles of this peski speed limit of the universe, the ship could travel with any speed needed, without the inhabitants even feeling any acceleration. Some mathematical work has been done regarding the energy requirements and the possible solutions of the spacetime geometries, so why should we ignore this? The answer is simple: it would require negative energies, we don't even know if this is physically possible. No one has ever created a warp bubble nor is it even so much as a proven possibility.

The case for antimatter is slightly better. We do know it exists, we regularly produce it. We even have stored minuscule amounts of it. So surely it's only a matter of engineering to create a dedicated antimatter factory and drive concepts like "Antimatter Catalysed Fusion" (AimStar) to become possible? The ships would still be bound by the universal speed limit, but could come arbitrarily close to it? so why not a ship that cruises at 99% the speed of light?

There is no experimental evidence for any kind of successful reanimation after freezing a complex organism.

If we want to avoid just using magic fantasy technology we will have to limit ourselves to technologies that have a physically sound foundation, have already small-scale applications, and could conceivably be upscaled. Inherently this will lead to us missing quite a lot of interesting developments! in fact we will be in a situation like Jules Verne, using the steam-powered technology of his time to envision submarines and space travel in a near future while completly obvious of any advances in electric engineering, computation and nuclear physics. So any kind of space ship we will discuss on the basis of todays technology will necessarily turn out to be a kind of steam-punk contraption.

The challenge
"Space [...] is big. Really big. You just won't believe how vastly hugely mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space." Douglas Adams

Size comparison (star=salt crystal, size of a galaxy, collision with andromeda),

Speed comparison (fastest man-made object),

Now if we are honest we have to admit none of those probes was explicitly build and launched to reach interstellar space. Their mission was to visit planets in our own solar system during the span of a few years, a mission they all very successfully performed. This begs the question, which kind of speed could we achieve if we wanted to?

So lets ponder which speed we could attain if we used the most powerful rocket that ver existed, NASAs Saturn V. But instead of using all its energy to lift thousands of tons from earth, lets start the journey with a fully tanked Rocket already in space.

To answer this kind of Questions, "How much speed can we obtain using a specific rocket" we will use a more than 100-year-old equation: The classical rocket equation, or ideal rocket equation It is credited to the Russian scientist Konstantin Tsiolkovsky who independently derived it and published it in 1903, although it had been independently derived by several other scientists as well.



The maximum change of velocity of the vehicle, $$\Delta v$$ (with no external forces acting) is:

$$\Delta v = v_\text{e} \ln \frac{m_0}{m_f} = I_\text{sp} g_0 \ln \frac{m_0}{m_f},$$ where:
 * $$v_\text{e} = I_\text{sp} g_0$$ is the effective exhaust velocity;
 * $$I_\text{sp}$$ is the specific impulse in dimension of time;
 * $$g_0$$ is standard gravity;
 * $$\ln$$ is the natural logarithm function;
 * $$m_0$$ is the initial total mass, including propellant, a.k.a. wet mass;
 * $$m_f$$ is the final total mass without propellant, a.k.a. dry mass.

Given the effective exhaust velocity determined by the rocket motor's design, the desired delta-v, and a given dry mass $$m_f$$, the equation can be solved for the required propellant mass $$m_0 - m_f$$: $$m_0 = m_f e^{\Delta v / v_\text{e}}.$$

The necessary wet mass grows exponentially with the desired delta-v.

what if we put a Sturn V in orbit, attach our most efficient engine, which speed can we reach?)

All that remains to do yo answer our question is to find the exhaust velocity, the dry and wet mass of each stage, and then plug these numbers into th equation:

Now of course since all stages are together at the beginning, we will have to add all the masses of all remaining stages for each of the engines. So when stage 1 begins its burn and throws hot exhaust gas with a velocity of 3 km/s behind the rocket, the wet mass of the whole rocket will be: 2813000 kg. When stage 1 ends, the remaining mass will be the dry-mass of stage 1 plus the total mass of the still remaining stages.

$$\Delta v = v_\text{e} \ln \frac{m_0}{m_f} = 3km/s \ln \frac{2813000kg}{736000kg} = 4.02 km/s$$ $$\Delta v = v_\text{e} \ln \frac{m_0}{m_f} = 4.13km/s \ln \frac{599000kg}{49500kg} = 10.2 km/s$$ $$\Delta v = v_\text{e} \ln \frac{m_0}{m_f} = 4.13km/s \ln \frac{119000kg}{13500kg} = 8.92 km/s $$

Combined, at the end of all three stages completely exhausted the empty last stage (with its payload) would have attained a speed of 23.14 km/s. Without any possibility to ever slowdown.

But of course we could do a bit better! After all, why should we use the less effective engine of the first stage, when we already have more effective ones. Infact we could use

Even if we use the best engine at hand, ignore all the problems associated with starting from the surface, construct a 10 times larger rocket then the largest one we have today, fuel it with the most efficient fuel - a one way trip to the nearest star would take ~ thousands (?) years.

How can we compare drives?
 * thrust
 * specific impulse

exhaust velocity - temperature

VASIMIR
Variable Specific Impulse Magnetoplasma Rocket

Oberth Effect
Oberth Effect

For example, as a vehicle falls toward periapsis in any orbit the velocity relative to the central body increases. Briefly burning the engine (an “impulsive burn”) prograde at periapsis increases the velocity by the same increment as at any other time ($$\Delta v$$). However, since the vehicle's kinetic energy is related to the square of its velocity, this increase in velocity has a non-linear effect on the vehicle's kinetic energy, leaving it with higher energy than if the burn were achieved at any other time.

Oberth calculation for a parabolic orbit
If an impulsive burn of Δv is performed at periapsis in a parabolic orbit, then the velocity at periapsis before the burn is equal to the escape velocity (Vesc), and the specific kinetic energy after the burn is: $$\begin{align} e_k &= \tfrac{1}{2} V^2 \\ &= \tfrac{1}{2} (V_\text{esc} + \Delta v )^2 \\ &= \tfrac{1}{2} V_\text{esc} ^ 2 + \Delta v V_\text{esc} + \tfrac{1}{2} \Delta v^2, \end{align}$$ where $$V = V_\text{esc} + \Delta v$$.

When the vehicle leaves the gravity field, the loss of specific kinetic energy is
 * $$\tfrac{1}{2} V_\text{esc}^2,$$

so it retains the energy
 * $$\Delta v V_\text{esc} + \tfrac{1}{2} \Delta v^2,$$

which is larger than the energy from a burn outside the gravitational field ($$\tfrac{1}{2} \Delta v^2$$) by
 * $$ \Delta v V_\text{esc}.$$

When the vehicle has left the gravity well, it is traveling at a speed
 * $$V = \Delta v \sqrt{1 + \frac{2 V_\text{esc}}{\Delta v}}.$$

For the case where the added impulse Δv is small compared to escape velocity, the 1 can be ignored, and the effective Δv of the impulsive burn can be seen to be multiplied by a factor of simply
 * $$\sqrt{\frac{2 V_\text{esc}}{\Delta v}}$$

and one gets
 * $$V$$ ≈ $$\sqrt .$$

Similar effects happen in closed and hyperbolic orbits.

Parabolic example
If the vehicle travels at velocity v at the start of a burn that changes the velocity by Δv, then the change in specific orbital energy (SOE) due to the new orbit is
 * $$v \,\Delta v + \tfrac{1}{2}(\Delta v)^2.$$

Once the spacecraft is far from the planet again, the SOE is entirely kinetic, since gravitational potential energy approaches zero. Therefore, the larger the v at the time of the burn, the greater the final kinetic energy, and the higher the final velocity.

The effect becomes more pronounced the closer to the central body, or more generally, the deeper in the gravitational field potential in which the burn occurs, since the velocity is higher there.

So if a spacecraft is on a parabolic flyby of Jupiter with a periapsis velocity of 50 km/s and performs a 5 km/s burn, it turns out that the final velocity change at great distance is 22.9 km/s, giving a multiplication of the burn by 4.58 times.

Gravity Assist / Gravitational Slingshot
Gravity Assist



examining the data of the above table shows with currently reachable technologies only nuclear pulse propulsion gives us the slightest chance of propelling anything over interstellar distance that has more mass than a dandelion seed and would arrive in less than a thousand years.

Is there a reasonable expectation that we can even buld any kind of technical system that stays functional for decades or even centuries?

Several Navies have Ships on active duty which are several decades old, albeit with regular and heavy refits.

On the other hand we already have several space probes active for decades which do remarkably well, usually is either the energy source, reaction mass or reaction wheels which limit the lifetime of these devices.

All in all the vacuum of space seems to be a remarkably well suited environment for longterm missions. Without the constant barrage of the elements technical systems have stayed functional for decades even if they had been build with mission duration of years in mind. It seems plausible to assume a system planned with a lifetime of centuries, placed in a vacuum, is well within our abilities. The main pitfall will be mechanical systems (actuators) and parts which are in contact with reactive chemicals, i.e. a breathable athomsphere, a.k.a. the habitable areas.

Drive
As the original Project Orion proposed, the main drive will be several thousand nuclear bombs.

Build as to be shaped charges, emitting most of their energy in two narrow cones towards and away from the pusher plate. The pusher plate itself is parabolic in shape. The thickness of the plate varies in such a way, that areas which will be hit by the most energetic particles are more massive, while further out the plate is less massiv. This should ensure an equal acceleration of the plate, without to much internal stresses.

Extending from the outer edge of the plate will be an magnetic nozzel to harness the energy of particles not within the plate radius.

To protect the plate from ablation before each blast the surface needs to be coated in an oil film.

All components hich can withstand considerable accerlerations, e.g. surplus material, nuclear charges, reactor, radiators will be placed directly behind the pusher plate and will encounter several g's of acceleration every few minutes.

The original Project Orion proposed a series of mechanical shock absorbers between the pusher plate and the remaining structures, instead our design will use an Eddy Current Break or a Linear Induction Motor. With each shockwave the pusher-assembly is rapidly accelerated forward. in the center of the assembly a 5km long keel is situated, in essence a large tower. This tower acts as the moving part of a linear induction motor. Around this keel is a circular node constructed. The node does not physically touch the keel, instead when the keel is rapidly pushed through the node is its momentum is gradually absorbed over the length of the keel. The recupperated energy is then used to move the node back to the fron of the Keel.

The node therefore encounters less strong accerleration forces and will serve as the central anchor point for the habitation areas.

Habitation
As we have seen in Chapter X it will be impossible to achieve flight times of less then several decades, on the other hand our ability to build (and test) systems with lifetimes of thousands of years is doubtfull.

A flight time of lower digits of centuries however seems feasable for the machine parts. Which leaves the crucial component: the human inhabitants.

It seems at the moment safe to assume that extended periods of weightlessness are diametral to human health, and even to plant life. Therefore any long-term habitation, not even to speak of multiple generations, requires artificial gravity.

The only possible way to create artificial gravity known to us is by acceleration. Indeed according to general relativity there is no discernable difference between a uniformly accelerated frame of reference, and a frame of reference in a gravitational field. However since we cannot accelerate the ship with any approachable fraction of g during the whole flight we will have to resort to the trick of using rotation. Since in a rotating container all objects are constantly forced to deviate from the straight lines they would naturally follow, they will constantly feel an acceleration, usually known as centripetal force.

For a given radius and a given rotation rate the centripetal force can be calculated using:

How much gravity is necessary? Natural deviation on earth is between x and y m/s², Astronauts on the lunar surface encountered z m/s². We have to rely on some speculation here, but it seems fairly safe to assume an artificial gravity of 80% g will be enough to remedy most harmful effects.

Population size
the lowest possible bound would be a population of 1 woman, birthing in each generation 1 child, at all times there would be 3 to 4 generations alive. This lowest bound gives zero margin for error, accidental death, inability of pregnancies and so on.

On the other hand by population genetics its estimated a population of 300 - 500 people could contain enough diversity to avoid inbreeding. However this bound can be lowered if we consider transporting banks of frozen sperm, eggs and embryos.

ZZZZ calculates in his paper a population size of 140.

An interesting approach would be to look at small isolated societies on earth to get an estimate on which number of peoples makes a sustainable population.

Jesides, Inuit, Rapa Nui,

To be on the safe side we propose a population of 300 with an average age distribution of...

Food production
A healthy human male needs 2500 calories a day, according to ZZZZ a healthy diet of mostly vegetables, supplemented with some poultry and eggs requires roughly 1 acre or 4050 m.

Our total population of 300 people would require therefore a minimum 1.22 km of land area. However, with vertical farming and hydroponics, some of the traditional farming areas could be substituted.

To create a surface with 80% gravity we will consider a stanford torus design, in essence a gigantic Ferris wheel whose constant rotation provides the centripetal force of gravity.

As a benchmark of possible torus measurements, we can look at current suspension bridges. The currently longest suspension bridge (by central span) is the Çanakkale Bridge of Turkey with a central span of roughly 2 km.

Engineering a "bridge" with a circumference of 6km suspended from a central node seems feasable.

With staying cables of 1 km length (radius), the habitat torus would have a circumference of 6.3 km. If each habitat ring has a width of 200m, the surface area of each ring would be 1.26 km^2. Employing 3 decks per ring, with a vertical distance of 40m would yield a total of 3.8 km^2., which is the same are of central park in New York. 4 such rings per ship would put the total living area at 15 km^2.

Oxygen regeneration
oxygen partial pressure

genetics of tibetians

Population Genetics

Psychological effects




BIOS-3

BIOSphere

Syd Mead Design Nichlas Benjamin Standford Torus



Size comparison: Aircraft Carrier, Suspension Bridge, Stanford Torus

Land area of Islands

Lo (sometimes wrongly spelled Loh) is an island in the Torres group of islands, in northern Vanuatu. The island is located 2.25 miles from the Toga Island As of 2009, the population of the island was 210. It had in 1979 a population of 84 people.



Rapa Nui (Easter Island) has a land area of 163.6 km2 and sustained a population of 3000-4000.

To sustain the caloric intake of a population of 90 people at least 200 acres or 0.8 km^2 are needed. High yield hydroponic and vertical farming not included.

One person breathes the oxygen production of around 8 trees.

Internal Layout
After discussing different problems and solutions in the prior sections, lets summarize:


 * The habitation area will be in rotating rings, with 1km radius and a width of 200m
 * Each ring will internally be divided in 3 or more decks, to maximize usable surface area
 * Agriculture will mostly be done in high intensity hydroponics areas, seperated from the larger habitation areas.
 * The ecology will be semi closed, i.e. some inevitable losses due to chemical reactions are anticipated and accounted for.
 * The ecology will resemble one of an isolated sweet water biome on earth, possibly like cloud forests on islands (canary islands, madagacar, new zealand)
 * The population will be ~100people per habitat ring, with a total of 3 to 4 rings.

If we lookmat artistic impressions of space habitats, like the stanford torus, the interior is usually depicted as a suburban environment or a recreational park with large water surfaces, single family homes, often bugalows, connected by small paths. Often a futuristic looking monorail is added.

This kind of suburban, low density areas are the least productive and the necessary infrastructure is spread out over a hughe area. Its is the most wastefull in terms of area footprint and typically relies on nearby cities to finance the necessary infrastructure.

Contrary to this depictions the population will be concentrated in a high density village of several apartmentblocks or multi-purpose buildings. This will allow a local population density of up to .... person per km^2, comparabe to (Monacco, Hongkong, New York).

This concentration will have multiple benefits:

The infrastructure for transportation, fresh water distribution and waste water extraction is much smaller and more efficient.

Safety anbd emergency measures can be concentrated around this highly populated area, e.g. special radiation shielding, emergency compartments with autonomous air supply, emergency generators. It will also allow to assemble emergency response teams in a timely manner, to equip them and coordinate them. Sports, entertainment and community services would also be provided in this village.

To allow fast access to all levels of the habitat, the town might stretch vertically over all levels inside a chamber of a hyperboloid shape (like cooling towers).

Because of the limited space transportation would not require any sophisticated systems, rather most transportation needs could be satisfied by using a low-tech solution like bicycles.

Large open water areas would also detract from the usable surface area, therefore at the deepest point of the central "vally" there might be a rather small creek for drainage of the surrounding areas.

Only at the depest point of the habitat ring, around and below the town, the central water reservoir might be accessible in the form of a series of ponds or a very small lake.

The ring volume will be divided by bulkheads into separable sections, these bulkheads may be open during normal operation to allow an unimpeded flow of material between sections but close automatically in the event of loss of electricity, decompression, or fire.

For aesthetic reasons thos section dividers could be designed like a rockface, although that's not necessary. The inner volume is therefore partitioned by a spiral, allowing to follow one path, crossing several bulkheads and thereby gradually climbing to upper levels.

To reinforce a sense of spaciousness it is important to make sure not every individuum will be able to traverse every possible path in a short time. Instead the pathways outside of the town and surrounding recreational areas should not follow a straight line, instead they should meander through the area and frequently branch out to allow different vistas. For the same reason the inner surface should not follow simply the curvature of the outside hull, instead two hill ranges should separate two outside vallays from the middle valley with creek. This way two or three path can be close to each other, without ever allowing a direct line of sight.

Depending on the layout it might also be possible to create hard-to-reach areas, islands, or areas surrounded by cliffs, to ensure that even after years some unvisited places retain an air of mystery.

Construction
To produce a viable biologically usiefull substrate (humus) out of the sterile and largely mineralic substances found in asteroids we need to setup an industrialzed version of the natural process of colonization. As a blueprint we can use the ecological activities on barren volcanic islands during the process of colonization.

inoculation with bacteria, fungi, algae folowed by moss and "flechten". Repeated introduction of plants acustomed to low naehrstoff grounds (sand, desert, mountains, salt marshes).

Fast growing plants capturing nitrogen and carbon. repeated tilling and keeping temperature, light intensity and humidity at optimum levels.

Filtering of heavy metals, charcoaling of plant material.

Due to the use of hydroponics and the introduction of small patches with higher fertility the remaining surface can still be covered with genuegsame plants used to low fertility grounds.

Dangers
Radiation

fire

pressure loss

collision

ecologic imbalance

forever chemicals

Sociology
While we do have buildings maintaining their structural integrity for hundreds of years, complex technical systems remaining functional after decades, and at least examples of semi-closed ecologies providing stability for millenia, we have to ask the question under which circumstances an isolated society can maintain stability and provide the skilled generations necessary for a success of the mission.

How much changes in a society over 200 years? - middle ages? - roman empire? - industrial revolution? - amish?

economics
Our modern societies are highly defined by the idea of division of labor. Work is broken down into smaller and smaller more and more specialist tasks which can be performed by specialists in a very productive manner. this division of labor permeates all factors of modern societies and allows high productivity. However in an environment with only a limited number of humans, such a division of labor is unfeasible. There will and must still be some degree of specialization, e.g. carpenter, surgeon, ecological engineer, it specialist, however the thought that of those 300 human beings some dedicate their whole working life to hair cutting, waiting tables or cleaning rooms or designing logos is ridiculous.

We can divide the areas of work roughly in 3 different sections - technological maintenance of ship-systems - maintenance of internal habitation systems (food production, ecology, light and air, housing, waste extraction) - human services (doctors, teachers, waiters, chefs, hairdressers, ...)

Possible solutions to get enough workforce for each sector: 1. mandatory public service, as is currently done in several nations for the military (e.g. draft). This can have different forms, either as a regular group activity done as part of the childcare and school system. We have examples in Kasachstan where students and schoolchildren are employed to help bring in the cotton. Even in western europe and the us the vacation times are historically timed to allow school children to help on the farm at the end of summer. To keep this example a regular activity for children and youth could be maintenance the ecology, basic plumbing, cleaning the light panels etc. as part of the curiculum. Expanding on this it is possible to mandate citizens to unpaid labor (firefighters, jury duty, draft) for either a set period (e.g. 1-2 years) or as a mandatory regular activity beside the normal dutis (e.g. every second week 4 hours, as military reserve). Especially needed is this for positions without a constant workload, e.g. physicians, fire fighters. Those would be parttime occupations with constant training and yet a

Instead of relying on a sufficient number of students to choose a vocation it is possible the reverse is true: the current specialists regularly searching for students ...

2. Another

Market forces and currency-based system?

Command economy?

AI / Expertsystems
in a limited population of a view hundred people its impossible to maintain indepth expert knowledge od less frequently used technologies and techniques. In a population of millions a piano builder can work fulltime and a surgion can specialize on knee operations. But in a minimized society where a knee operation isonly necessary once every ten years a lot of expertise will unvermeidlich fall out of the collective knowlege. This will be especially true for highly specialzed equipment build to withstand for centuries (e.g. fusion reactors, probes, ...).

It is not enough to just provide all blueprints as well as technical documentation as well as books with the knowldge. It is necessary to have an Actor who actively participates in discussions, gives outside perspective and draws attention to possible problems.

A sophisticates expertsystem loaded with the expertise and practical work experience of years and years of every engineer, mechanic, designer, biologist, sociologits, physician should be used for this.

Imagine that for each and every engineer working on a subproject like "pumpsystem of hydroponics", from the very beginning of training until their retirement automatically every problem, every question, and every tried solution (failed and sucessful) is automatically documented. From different engineers with different (often contradictory) strategies. Each students questions of a hundred students in a hundred ifferent studies, answered by dozends of different dozends...

Arrival
How to break a multi-million ton ship coasting at 0.1 light speed towards a foreign sun?

The breaking phase will itself take decades, utilizing solar sails and magnetic sails as well as repeated gravity assists in the last phase.

It might be beneficial to to use high risk, high g maneuvers for some equipment (e.g. mining and construction). If successfull the mining for resources can start years before the ship itself reaches its intended orbit. Depending on the sucess of the mining operation it could be possible to expel those resources and waste products which can easily be replaced (e.g. water) to minimize the ships mass.

mining operation
All mining operations will need to be highly automated and largely autonomous.

1. An object which spectroscopically has been identified as a worthwhile

2. An orbital mission, using gravimetric, spectroscopic and LIDAR information to create a complete map of the surface down to cm resolution.

3. A second orbital mission, which uses sun light to generate power, which in turn can be beamed via microwave to the surface installation/.

4. A "Phage" will land on a suitable area of the surface and anchor itself. The "phage" contains the microwave receivers for energy generation, communication equipment, construction material and machines for pre-processing.

5. Most importantly the Phage will contain a large set of robots, each falling into one of several categories of specialization:


 * "Scouts", analyzing material and reporting chemical composition
 * "Grinder", deconstructing material and preparing for transportation
 * "transporter", moving material from grinders back to the phage for processing
 * "builder", using extruders to stabilize pathways
 * "maintainers", maintaining and deactivating damaged robots.

6. These robots will follow a rather simple set of instructions, relying on emergent behavior to fullfill their collective goal as a swarm. The controlling instance of the phage only relays general guidelines, e.g. priority of material to harvest, without detailed control over individual robots. 7. A steady stream of ore of specified composition will arrive at the phage, there this ore might be preprocessed in a very limited way, compressed and sintered into blocks of standardized weight and composition and finally ejected into space using the phages catapult. 8. Once in space the ejected blocks are collected and transported to the actual processing and refinery station.

The phage will be occasionally replenished with raw material for the extruders as well as replacement robots.

It shpould be noted that this operation is not a von-Neumann swarm, neither Phage nor Robots are self replicating or even able to spread beyond the celestial body they are placed upon. Furthermore without energy and pre-processed material from the outside this artifical ant heap would loose its ability to function in a very short time.

However, as long as energy and some basic building blocks are provided an automated facility like this should be able to begin and retain operations for years without human intervention.

This will allow the placement of several phages on different bodies of diverse composition (dirty snowball, heap of rubble, chondritic asteroids) long ahead of he arrival of the main ship. This way a large amount of pre-refined rawmaterial will be already accessible when the ship enters the system.

Expansion
A very first step upon arrival, will be deployment of a successive stream of probes, beginning with very high speed fly-by probes, traversing the system at 0.1c in a few days, down to probes using a series of gravity assists and possibly high-g aerobreaking to allow orbital insertion. These probes would arrive years ahead of the main ship. Combined with the information from on-board telescopes the colonists will have considerable information about features and composition of most bodies in the target system.

The main ship will most likely opt to stay afr away from any specific body to protect against interplanetary debris. However highest priority would be to replenish all material lost during the voyage.

first steps
On the way towards realisation of Project Hephaistos we will have to build up a space based economy first and get experience in constrction projects on the kilometer scale lasting decades. To achieve industrialization of our solarsystem we will need to start with the semi-autonomous ressource extraction and refining processes as described in chapter X.

The necessary advancements in robotics, AI and cooperative swarms will be of use independend of space exploration

Relevant current project proposals:

Followed by construction of medium sized habitats (Kampala) up to kilometer sized ecologies of the stanford torus design. This will require.... advancements in metallurgy, automated welding, ecology control...

The expert systems as described in chapter X can be developed right now and would prove useful in any isolated region or to provide high quality education at low costs. A statesponsored program should be started to .... special grants to teaching institutions and industry for allowing constant audio-visual surveillance during whole academic careers.