A revolutionary way of launching a spacecraft into orbit by Tapani Hakonen
Spaceliner1 <<<>>> Spaceliner2 <<<>>> Descendenting<<<>>> NASA <<<>>> Launch <<<>>> Appendix <<<>>>A "Wild West"
A spaceliner is a flying vehicle, that can take off from a rather ordinary airport and fly into the
orbit and return back to Earth to an
ordinary airport. During the flight no parts are discarded from it, and as fuel oxidiser it uses mainly the free oxygen of the atmosphere.
The tasks of a spaceliner include transporting goods and people into the orbit and back, to act as a short-term research station or factory. An adaptation of the spaceliner can be made to make flights between continents much faster than they are today. For this flying vehicle to be able to perform such demanding tasks it has to differ greatly from the present day flying devices - aircraft as well as space rockets and shuttles.
Why then are we aiming at this kind of a vehicle ? The answer is mainly economical, but it is environmental as well. The present day space craft can mainly be used only once, which makes them extremely expensive. Their costliness is also due to their low coefficient of efficiency: the original weight of an aircraft in proportion to the useful load carried into space is something at its best 40:1. That means that the cost of the transport is close to 10000 $/kg. It is possible that a spaceliner will reduce the cost of transport down to one-hundredth, which is 100 $/kg.
If this becomes true it would really mean the beginning of space era for mankind. This is a "Gateway to heaven" for mankind and it would make possible the birth of the space industry in space - it would make space tourism possible - the first space people and colonies would arise - travels further in our solar system, maybe even further, would become possible - scientific research possibilities would increase. It is impossible to foresee all the things that it will make possible. It is clear that time and steady conditions in the world are needed for all this. Making a spaceliner will naturally cost a lot in the beginning but its operating expenses are relatively low. Later on, with more experience the building will also become cheap. The course of prices and the general development of the field will depend on whether there will be work for the spaceliner (APPENDIX ). Do we want to step on that endless road that the spaceliner makes possible? People get exited about circus tricks for a while, but soon grow tired of them. Space adventure will not last long unless it can be utilised and brings economical profit.
Environmental questions are problematic. The present day space rockets have sown so much junk both near the launching areas and in space itself. Our modern space fuels, often rich in chlorine content, have polluted nature badly since they were made with only the technical efficiency in mind. Today thousands if not millions of bigger or smaller objects or chips orbit in space, all dangerous because of their high speed. The chips orbiting lower will eventually come down braked by air resistance, but some of them will orbit Earth practically eternally being thus a permanent danger for space travellers. Collecting useless space junk should be started immediately. Old satellites or those that have gone off their orbit have often caused fear for people.
If mankind is still at such low ethical level as it is nowadays the indirect environmental effects can be sad. When transporting goods into space many kinds of polluting things can come off them and be dangerous. The most difficult rubbish will probably be all small, hard things like nuts, spanners etc. since it is difficult to see them and thus collecting them will be hard. A "Wild West" may become prevalent. Very quickly the space becomes impenetrable.
The environmental problems will best be handled if traffic is only allowed for few space stations with strict norms for pollutants. Many will probably try to use space for military purposes as well. I am concerned about the use of Spaceliner militaristic purposes. Weapons are enough. More is not needed. The population is limited to increasing the well-being and democracy. Spaceliners task is to take the humanity out into space. This is my first idea even at school year 1959, but it does not happen in my lifetime. Maybe Spaceliner not fly ever, if the result is an efficient rocket, carrying a cargo couple of orders of magnitude lower cost than the current ones. So far so good.
Before even the first spaceliner is allowed to take off norms that cover everything, including fines and an inspection system, have to be created. The norms would be different for different height levels since the permanence of the pollution will depend on the altitude. The Space police would also take care of removing all falling and other junk. Ruthless exploitation of space must stop - right away! From now on: When one operation is over in near-Earth space, the satellite must bring down by small rocket. Without preventing measures the newborn spaceman will be suffocated in his cradle.
In general, is it possible to produce a spaceliner that is capable of such great performances? In my opinion it is, since by using hydrogen and methane as fuel it is possible to plan a spacecraft that will not need oxygen and that will reach the necessary speed of 8 km/s. The jet engine will thus be radically different from the modern types. The ramjet engine, impact tube used here is known even today but has not been needed in aircraft since people have been content with the slower speeds. The speeds of military or civil aircraft have hardly risen during the last 30 years. A disadvantage in using a ramjet engine is that they need an external power unit for take off acceleration. Furthermore, it is more difficult to adjust.
The spaceliner presented here has two very large ramjet engines. ( Spaceliner2 -my preconception) With big ramjet or scramjet - my concepts are cluttered - engines a good thrust is achieved both with rather low speeds and in extremely high levels and with high speeds. The thrust is equivalent to that of a rocket. Of course there will be problems in using a ramjet engine, but in my opinion they can be controlled. Observing the fuel combustion inside the ramjet engine during the flight has to be versatile. On the basis of this observation and by considering the velocity and the altitude a computer adjusts the combustion in the ramjet engine by adjusting the amount and the quality (hydrogen or methane) of the fuel, the fuel feeding places, pressures on different sides of the impact tube, pressures of the fuel jets, thickness of the fuel jets, the ranges of the spark showers etc. Some of the very extensive fuel jets could crash into each other at the narrowest spot of the impact tube and ignite when fire would quickly spread all over the tube. The combustion has to be very fast.
On the basis of the former it is obvious that ramjet engines are not the only power units of a
spaceliner. A starting thrust is needed and rocket power for ascending in space. Maybe at least in
the beginning the necessary velocity is not achieved with ramjet engines only. Why not use only
hydrogen as fuel, why is methane used as well? The reason is the low density of the liquid
hydrogen. Even though the energy content of the liquid hydrogen is 2,5 fold compared to methane
including the weight, if counted according to capacity the energy content is about one fourth. So that
the plane would not grow too big and its fuselage thus extremely heavy it is useful to construct it so
that it uses methane during the early phases of the journey and finally hydrogen with high speeds.
The ideal lies probably somewhere where the weight of the hydrogen fuel accounts for half or one
third of the amount of methane. Hydrogen and methane are naturally linked to one another: With
help of a catalyzer it is easy to produce hydrogen out of methane. When liquefying both of them the
necessary amount of liquid oxygen can be produced. The energy for producing and liquefying these
fuels comes either from natural gas and/or electricity.
After considering the structure of a spaceliner for years (since year 1959: Flight journal as inspiration). I have ended up with the solution illustrated in optimistic pictures 1 and 2. The vehicle is characterised by a long, light nose cone that cleaves the air like a wedge. At the same time this light nose cone acts as a hydrogen container. During the flight the hydrogen cools off the nose cone which would otherwise become too hot because of air resistance. The hydrogen, of course, boils inside, but the boiling part of it will be led to the impact tubes. Behind the nose there is a cockpit and the actual payload bay. This way the payload bay can be made extremely spacious both considering its length and its diameter. The outer appearance of the spaceliner can deviate greatly from the above illustration but it includes the main features by and large. Due to the structure the pilot can not see forward. He will only be able to "see" with the help of meters, monitors, computers and GPS. As the matter of fact, computers control and conduct the flight. On the first flights, test flights, when safety is still poorer, the crew could leave the plane with the help of their ejector-seats as in fighter planes. Behind the payload bay there is a methane tank and behind that an oxygen tank and quite in the end a rocket. It is difficult to estimate the size of the oxygen tank. It will probably be rather big in the earlier versions when the payload is correspondingly smaller, but in the later versions the oxygen tank is small. Its size will probably also depend on how high the flight will reach and what tasks will be performed. The walls of the oxygen and methane tanks have to be made so that they are perhaps easy to transfer to different kinds of flights. The amount of hydrogen will probably be the same on every flight - full tank. For the flight properties to stay at least somewhat steady during the flight the fuel and the oxygen have to be situated so that the centre of gravity will not shift, at least not much. The heavy oxygen which is used last will be situated at the rear end to counterbalance the hydrogen in the front.
The load bearing surface of the spaceliner consists mainly of the plane fuselage which includes the level bottom of the plane and two big impact tubes. In addition to these the plane is supported by smaller levels with guide surfaces at their ends. This surface acts as a braking surface which becomes hot when descending on Earth. It has to be coated with a ceramic heatproof layer. The impact tubes on both sides of the fuselage form a structure that supports one another. In some models the payload bay has to have doors that open upwards as in American orbiters for unloading cargo. When this is the case the support of the impact tube is really necessary for increasing sturdiness. At least in passenger versions the roof of the payload bay has windows.
The landing gear is built in the same way as in ordinary aircraft. The extreme conditions where they are used make the task difficult. After the plane has taken off the front landing gear, for instance, is tucked up nearby the hydrogen tank, temperature below -250 C . The front landing gear will then become cold and the rubber in it becomes as hard as glass and can go to pieces with the slightest bump. When descending the same rubber becomes easily heated and can burn even though it is sheltered by ceramic tiles. At least the materials for the front landing gear have to be chosen from other than the present day materials.
As previously mentioned, the main sources of power are the impact tubes but the plane needs auxiliary power units (or two for security). Such is a rocket that uses liquid hydrogen and liquid oxygen. It does not have to have a very strong thrust power in proportion to the size of the plane since it operates when the plane is flying horizontally and mainly with high velocities. Furthermore, there are small nozzles on different sides of the plane, from which hydrogen is let out for turning the plane in free space. A faster jet is achieved if the hydrogen can be heated in the Sun before letting it through the nozzles.
Special tactics is here suggested for the plane's ascent. The plane is pushed until the velocity where the impact tubes can give sufficiently thrust is achieved. If this can be done great amounts of fuel and other resources can be saved. The launch vehicle would be some kind of super car with efficiency of 100000 kilowatts. It would partially support the rear end of the spaceliner so that it would get a better grip of the ground surface. The take off would happen so that an engine with a power of about 1000 kW would start pushing the plane up to a certain velocity, maybe up to 20 m/s , and would then be disconnected. The same engine would now charge turbochargers for a 100000 kW engine which would accelerate the velocity up to 100 m/s , then it would be disconnected and brake with the help of a brake parachute. The speeding path on the airfield would be one kilometre long and would last less than a minute. At this stage the speed would be high enough for the impact tubes - the plane would rise and start speeding up. If this does not work it will also be necessary to use rockets in the beginning - a rocket engine should at least be readily available. On the other hand the plane has to be able to take off from any airfield even without the help of a launching vehicle by using rocket engines, even though the take off will then consume 10 tonnes oxygen and fuel.
It is the third custom to leave for the space "in the back" of the big aeroplane. One must make the start easy and routine. The impact tubes are started only in a 10 kilometre height and 0.9 mach speed. The danger is militarising of the operation. The scramjet engine does not help against terrorism.
The impact tubes need ignition and the greater the velocity the more efficient and exact the ignition has to be. The ignition is done with the help of shower sparks that rotating, emery grinding wheel -like disks hurl with fast speed in the area of the whole impact tube's diameter approximately at its narrowest spot. The purpose is that all fuel is ignited exactly at the narrowest spot in order to make the thrust most efficient. It may be that an advance ignition will be needed - maybe the spark generators have to produce the jet even before the narrowest spot. The spark generator consists of a disk weighing approximately few dozens of kilograms. Some kind of bit leans on the disk, and the place of the bit can be adjusted in order to direct the shower sparks. There has to be many disks at both ends of the impact tube, and they will wear out almost totally during the ascent. The material for the disk is chosen so that it will also act as fuel: e.g. aluminium- and magnesium-bearing granules. The granules will be of different sizes so that combustion will be possible everywhere in the tube. At high velocity (more than 1 km/s) it needs no sparks. The shock-wave will ignite fuel at the narrowest place of scramjet.
In my opinion, the spaceliner should be built the same size as modern aircraft, which means that the take-off weight is about 200 tonnes. There is lot of experience in the building and behaviour of aircraft this size. The same subcontractors can produce rather similar structures and spare parts, and the same workmen can assemble these planes. Of course, a spaceliner is different from ordinary planes in many ways, but not in everything. Later on, freighters weighing maybe even 1000 tonnes will be built, but at first they will not be needed. A plane with take-off weight of 200 tonnes could, after probable difficulties at first, carry even 60 tonnes freight into the orbit, provided that the impact tubes could achieve a thrust of 8 km/s. If the impact tubes would only give a thrust up to 4 km/s the cargo would only weigh 10-20 tonnes since plenty of oxygen will have to be taken along.
The maximum achieved velocity will depend much on the air friction inside the impact tube. The greatest efficiency would be achieved if air would act adiabatic in the impact tube, that means, without friction. Friction can be reduced by "lubricating" the impact tube from inside with cold hydrogen. It is known that the viscosity of hydrogen is smaller than that of air, and the viscosity of cold hydrogen is even much smaller. By passing cold or liquid hydrogen through the grooves that there are in many places on the inner surface of the impact tube, before the narrowest spot of the tube as well, friction decreases. It is obvious that this hydrogen will not combust very soon, but it has time to lubricate. The hydrogen coming from the next groove lubricates the tube after the combustion of the hydrogen in the previous groove. There has to be about 4 - 10 grooves.
Electronics and computers form a central part of the functions of a spaceliner. Radar, video cameras, transmitter and receiver antennas are mounted in front of the hydrogen tank in the nose cone. There is a danger that the equipment becomes overly heated, but to prevent that it can be immersed in coolant e.g. in ice compress. However, the plane has to be able to fly even without the help of the nose cone. Computer equipment is multiple, all computers have spare computers. Furthermore, the system is hierarchic so that the crew has supreme authority, an automatic steering system is under the crew, and under that there are the monitoring and control computers. In a crisis situation the computers can be bypassed, so that the plane can be controlled almost manually from the cockpit.
The fuselage, ailerons and impact tubes are made of steel alloys, probably of titanium alloys, coal fibre and other composite materials and in future carbon nanotubes. They form multilayer, strong heat- and cold resistant structures. Light metals can be useful materials for oxygen and methane tanks because of their good resistance of cold. Insulation is needed at least for insulating the crew compartment and the payload bay above all from coldness.
Almost immediately after refuelling the plane has to take off so that ice will not collect on the plane surface. The gas turbines and ignition disks begin to rotate. The launch vehicle pushes the spaceliner to the end of the runway and after systems check starts accelerating, first slower, but soon the main engines of the launching vehicle start in full power and the plane speeds on the runway for a kilometre. The launching vehicle has fulfilled its purpose - brake parachute opens up -the vehicle stops. The impact tubes of the spaceliner start developing thrust. At first the acceleration is slow, maybe 0,2 g but it rises all the time - at the end of the runway the speed may be 150 m/s and acceleration 0,3 g. The plane takes off, the landing gear is drawn in. At this stage, however, the plane probably needs the help of rocket boosters when the rocket would accelerate the plane for ten seconds immediately after the launch vehicle has detached itself from the spaceliner. The plane flies first relatively low increasing speed and then rises at a steeper angle. It reaches sound velocity in an altitude of 10 km. The plane continues increasing speed and altitude so that the impact tubes act at maximum, yet safe, efficiency. The impact tubes work efficiently at high velocity even at an altitude of 30-40 km, perhaps 70 km, where the pressure is below one thousands of the atmospheric pressure on Earth.
NASA: "It's Official. X-43A Raises the Bar to Mach 9.6 Guinness World Records recognized NASA's
X-43A scramjet with a new world speed record for a jet-powered aircraft
-Mach 9.6, or nearly 7,000 mph. The X-43A set the new mark and
broke its own world record on its third and final flight on Nov. 16, 2004."
The maximum velocity of scramjet may be perhaps Mach 15.
Final acceleration is done with the rear liquid hydrogen rocket engine, if needed. To some extent adjustment with gas jets is needed so that the right course is achieved. The plane ascends in the orbit.
We need to fulfill tree basic types of tasks: 1. transporting people 2. transporting satellites 3. transporting liquids. Therefore they will need different versions of the spaceliner.
In space the plane fulfils its task, e.g. opens its doors, unloads its cargo, sells excess fuel to a station. The journey back to Earth begins as the plane directs itself with gas jets and gives a little push with its rocket engine and starts descending towards the atmosphere. The spaceliner has to enter the atmosphere in exactly the right position and keep this position exactly right during the whole period when it becomes hot, that is, the bottom facing the direction of travel. Torque force, that turns the plane away from this position, may occur and gas jets are used to prevent it. It would be good if it could be prevented with flaps or elevons. The plane's centre of gravity is then important and depends on how much fuel is left and on the cargo. In the lower atmosphere after the heat is over the plane turns to its normal landing position, approaches and lands on the field. The impact tubes can also be used at the approaching and landing stage. The aim is that the plane will act as an ordinary aeroplane from many airfields, or even that it could change the airfield during the descending stage if necessary. The biggest limitation in choosing the airfield is probably the extraordinary fuels that the planes use: liquid methane, liquid oxygen and, above all, liquid hydrogen. I think that tank trucks can be built to deliver these fuels as well.
At my desk
and when jogging it is difficult to get any further in planing the spaceliner. I have had many opinions about
some functions, e.g. landing, over the years. I am still not quite sure how it should be realised. An
alternative way of landing could be braking with the impact tubes. They brake efficiently if no fuel is fed
What about braking with parachutes of covered carbon fiber - but what a cover, ALD-coating?
One thing I am positive about:
This is the best way known in physics of ascending into the orbit from Earth.
This presentation does not include the calculations that I have made. Often they are just rough estimations. The empty weight, for example, is an estimated 50 tonnes on the basis that the weight of planes that size is normally something like that, the impact tube would weigh 10 tonnes, forward part 10 tonnes, rear end 20 tonnes. This estimation could, however, be a starting point for planning. At least half of the weight of the forward part can be taken off in it. But neither the impact tubes nor the nose are attached together as separate parts to the rear end of the fuselage, they are rather integrated into one unit. In principle the energy from liquid hydrogen is enough for flying around the Moon and back with a spaceliner that has impact tubes, even to the extent that the payload weighs as much as fuel is consumed (1 kg hydrogen gives in principle as much energy that it would give an object of 1 kg a push of almost 16 km/s - oxygen is taken from the atmosphere and is pushed away from it - the fuel value of hydrogen is more than 120 000 kJ/kg. In practice it is an other thing whether it will succeed. Furthermore, the energy of the liquid hydrogen is in principle enough for ascending into the orbit even when no liquid methane is used when the payload is somewhat lighter, but it is compensated by the notably more inexpensive price of liquid methane (1/10). Part of the fuel could even be gasoline.
Each sector needs its own specialists to refine on details with computer programs, wind tunnels and mathematical and physics models. By combining thoughts of the various specialists the final drawing of a prototype begins, from which the final prototype is then made. Various tests are made with it, first on the ground then gliding tests in the air - after a while tanks are filled with fuel - velocities rise - one day the plane ascends in the orbit. After trimming the plane even carries cargo. If we concentrate our forces this all can take place in less than ten years as the moon rocket was built with great enthusiasm in the USA in the 60's. Then all the trouble was not in vain, instead it produced many both material and intellectual results.
The launch and expecially the first minute is most dangerous. At the beginning the crew will be not in the spaceliner and it
flyes by remote controll. Later the crew will have
ejection seats and finally after hundreds flights without ejection seats. The first Spaceliners will be small, unoccupied and relative slow - for testing. Coming models
can transport small cargo and later perhaps truck cargo. The launch, of course, manages without a catapult or with big aeroplane and more resources.
Previously we have mentioned a huge satellite, a manned space centre that would be the main objects of a spaceliner and that would serve for many purposes, like
The base could be international and controlled by a large international community, e.g. the UN or some other similar organisation. It would be located in circular orbit so high that it could not came down for dozens of years, but on the other hand so low that the radiation belt will not reach it. A suitable altitude might be 400 - 600 km from Earth. Of course, the base would be kept in space for indefinitely long periods, it could even be lifted higher up, if necessary - maybe waiting for the next civilisation. However, this altitude is the most practical. So that the satellite could observe Earth and it could be landed on from many other bases the inclination of the orbit in relation to Earth's equator could be about 67í. It would travel between the polar circles and thus observe whole Earth. Due to the huge size of the space centre a versatile "infrastructure" can be built on it, offering quality of life and leisure activities, there would have to be artificial gravity with gardens, jogging trails, water pools etc. Better care can be taken of "runaway" people and objects. A large hall also means that changes in air quality and temperature can not be dangerously rapid.
The building of a space station would be started maybe by bringing a huge fibre glass pouch (weighing maybe 60 tonnes, fibre glass is UV-resistant) that would have a couple of air locks and that would be inflated into its shape with little pressure. During the next flights more thickness for the walls can be brought through the air lock: maybe LLDPE-polyethylene, metallosenics as catalyst, strong and clear plastic. The inside would be handled with fluorine or with fibre glass carpets. There should not be much combustibles, maybe only documents and fresh, damp vegetation, nor should any pressure tanks or explosives be brought in.
While the walls are being build stronger the structure will get stronger and its radiation resistance and resistance against meteorites will grow all the time. The thickness of the wall would be about 10 cm. The walls of the station can probably also be strengthened from outside by wrapping spirally a fibre glass carpet around the station at a later stage, if necessary. Solar panels,that would also act as protective boards and help in fine adjustment of heat, could be mounted on the outer surface, slightly separate from the surface. The station would be set rotating thus creating centrifugal force. The rotation period would be about 20 - 30 s, which makes close to the gravity in the Moon. With this speed you can run yourself into a weightless state inside the rotating hall.
Pressure would be set maybe to 1/2 of the atmospheric pressure, oxygen would account for 20 -25 per cent and the amount of carbon dioxide would be rather large. The halls would have light partition walls for soundproofing, intimate and peaceful conditions, or there would even be very light white "blocks of flats" with no elevators between different floors (Illustration 3).
For vegetation and living it would be good if a rather huge part of the outer wall would be transparent to light - the adhesive medium, maybe some type of silicone, would have the same refractive index as fibreglass (lighting more than 50,000 lux). The vegetation is chosen so that larger and larger part of oxygen and food is produced in the hall. The vegetation could at some parts reach the whole free air space of the hall, so that the milieu would resemble a rain forest. It would produce both oxygen and food - there are not any photons here to loose. Potato and tomato are perhaps the best plants in space. Productivity of tomato can be 100 kg/m2/year. Potato and tomato patchs are far end of the air dome in shelves. Plants will also be chosen so that they reduce various air pollutants of the station.
Vegetation is not meant for plain "agricultural production", but the purpose is to make the environment paradise-like and pleasant for man to live. Those parts of the outer surface that stay under the buildings and soil are painted titanium white or covered with solar panels that are slightly apart from the surface in order to keep the temperature low enough for men and assimilation, maybe 25 deg C. Meat is brought from Earth, but space pork or space turkey could be served at Christmas. Biological waste will be composted - water is partly distilled, partly used as fertiliser. There will be such amounts of human wastes that the flora will not be able to handle it all. A waste disposal centre is needed to take the air from the worst places, like toilet bowls, composts, cooker hoods, and to deal with the big molecules of air with activated charcoal and to blow some of the wastes back towards Earth. The blow backwards will keep the station in its orbit.
Later on this kind of big halls would be joined and there would be airlocks both to other halls and possibly for exiting. The air locks between the halls are normally open, in case of emergency and in hours of resting they are closed. For cases of emergency there would be space suits that are easy to dress on and simple in each apartment. The airlocks close rapidly and at the same time give an alarm if there is even a slightest hazard. The closing will take place so that the "less dangerous" door, i.e. the door on the high pressure side, closes first, in other words, the airlock waits for those getting into safe. If there are many halls connected together a connecting passage or rails have to be build on the axis of the halls for quicker transport between both ends of the hall chain. Some kind of vehicle, "a buss", with plenty of room for passengers and cargo could run there and back. The space station would look like chain of small sausages rotating around the same axis. As the town grows the chain gets many kilometres long (Illustration 5). Between halls would be elastic safety walls.
Illustration 5 "A space city"
Structures that are not rotating are mounted in bearings at both ends. They are connected to the rotating part through the airlocks. These structures are connected with the solar panels and antennas. A bearing and a pressurised, round airlock between a part that rotates and another one that doesn't needs really high-tech engineering: 1) It must not leak, at least not much (suitable lubricant), 2) since there is friction in the joints (roller bearings, sealing) an electric motor is needed as well as a control system to keep the right rotating speed, 3) people and goods have to be able to travel easily through the joint i.e. the airlock. Arriving spaceliners dock on the part that does not rotate.
Of course, there would be other structures outside these maybe connected through cables: manufacturing and research plants as well as warehouse containers. The spaceliners themselves could naturally act in certain cases as factories connected to huge solar panels, but normally the containers are removed from the spaceliners and their contents taken elsewhere for further processing. After finishing the processing inside the spaceliner they return to Earth, often to a place other than that from which they took off.
Similar space bases can later be built further in the space: to an equatorial oval orbit (400 - 40000 km), to the orbits of the Moon, Mars, asteroids etc. The interesting equatorial oval orbit is problematic because of the van Allen radiation belts. When passing them through you must absolutely stay inside the halls and the walls have to be thicker. A space walk of a maximum of 6 hours can only be performed at the furthest end of the orbit. An additional velocity of merely 1 km/s is needed for getting further into the space or to the much used synchronous orbit (Illustration 6).
The further from Earth the space station is built the more strict norms there have to be for
pollution: In the distance all trash has to be recycled - all food and oxygen has to be
produced there - the system should also be hermetically closed. Man will conquer and colonise the solar
system, perhaps further, with this kind of space base, although it will take time and many generations. See
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I am very thankful if somebody can translate all these articles. I do not have the resources to translate many languages.