(Permalink) Do we have the right to totally obliterate the natural evolution of a planet like Mars or Venus? I am not sure. Already today the tendency is to make a natural reserve of space and planets, and even of uninhabitable zones of Earth. So it may happen that the idea of terraforming a planet for colonisation may be not applicable at all, and this chapter not worth reading one line further.
The case is even more complicated if we consider another solar system: who is the owner, in this case? Who has the right to take it as a living place? All the more if we consider than not everybody can?
In the short term, many consider that colonizing other planets is the solution to relieve an overcrowded and exhausted Earth. This view is of a criminal naivety: the problems which happen or Earth come from our mind, not from the planet. And we shall carry these problems with us wherever we go. Many already did the experiment: the Mayflower people, the Soviets, the Hippies... all left an ancient world they accused of all the evils, just to reproduce the same evils as soon as they opened their luggage in their new place. So if we take Mars, it will be overcrowded in its turn in 20 years.
So the problems which happened on Earth will have to be solved on Earth, as they are spiritual and psychological problems which are to be solved by spiritual or psychological methods. Especially, pollution and overpopulation all have affordable technical solutions which just await that we have the will to use them. Personally, my very first spiritual feat at teenage was to sleep with a woman and NOT make her pregnant. And without pills or rubber. So let me laugh...
The view of colonizing other planets for escaping our problems on Earth has a well known supporter: Stephen Hawking, among alas many other high level scientists. He is considered as a kind of semi-god by the media, due to his charismatic popularization of physics, and his painful medical condition. However none of these two give any authority in the human or spiritual domain. And how sad to see scientists defending the arbitrary religious dogma of having to reproduce and expand forever.
In more, many make the reasoning that it is enough to launch a rocket to be able to colonize planets and stars. They simply do not realize the huge undertaking of bringing all the required impedimenta on another planet. In the time of Christopher Columbus, people just had to bring some tools and seeds out of wooden ship, to be able to colonize new lands. But on another planet, we need much more: air, water, and even the earth itself have to be brought, at such a cost that a simple wheat grain would cost more than the whole Columbus expedition. And this just for living in boxes and tunnels, with mates who can turn in tyrants, as it happened in many Hippie communities.
At last, if there is some kind of interstellar police, the moment we start to colonise other star system may too be the moment they manifest to us... your papers, please.
Mars is considered the easier to live on. But will this happen?
(Permalink) Astronautics is precisely demonstrating the contrary: robots and remote controlled devices are more and more taking over on Human controlled vehicles, because they are much cheaper, simpler and they pose much less logistical constrains. This makes that the interest of even simply a science base on Mars is vanishing fast. Even mining colonies are fading in an unpredictable future: it is much simpler to mine asteroids, especially the ones which threaten Earth. The reason is that we just need to deflect a bit the mined material, while from Mars we need to extract them from the Mars gravitational well.
Admitting that we install a base on Mars, we cannot consider this as living on the planet: to remain until our death locked in tunnels or cans is not called «living», it is called to be in jail. With no possible evasion. Ever.
(Added October 3, 2017) For this reason, we can consider the today Mars colonisation projects as at least prematurate. In the today context, they would be anyway suicide missions. In more, it is not to a private society to decide if we must go on Mars, and how. Add to this the contamination of Mars by Earth bacteria, or worse martian diseases brought on Earth. The project also evacuates all the political, cultural, emotional and spiritual sides of the life of the colonists, incarcerated in their space coffins. At last we must rebuke once and for all the intellectual imposture of abandoning Earth and its inhabitants to pollution, while pretending to do better elsewhere without any social or spiritual project. Let us remember that all the attempts of this sort failed shamefully, when they did not turned to the worse dictatorship.
So really living on Mars means that we can stroll in the open, hear birds, smell flowers, go in wild places (a very short dream if we do the same overpopulation on Mars than on Earth: it will soon be covered with concrete). Without speaking of the necessary cultivations for feeding the colonists. Problem, on Mars, there is no air, there is no water, there is even no earth, no organic matter.
So that terraforming Mars «just» requires to bring all this. And the only way is to deflect comets and asteroids so that they fall on Mars. Admitting that the impact does not disperse the water and gasses, such a process may require thousands or hundred thousands of years, depending on the amount of sustained effort we want to invest during such a length of time.
Added February 14, 2016: Such a duration definitively exclude any egocentric «investment». To abandon capitalism (chapter VI-8) could be the very first investment needed to inhabit other planets.
I retain the paternity of the word comclast© (literally: comet breakers) (note 93 on the use of ©), for spaceships able of deflecting comets in order to feed a planet with life-supporting materials. Ideally they are automated, and use ion thrusters to drive in space. As energy source, they need nuclear fusion, so that they have to «feed» on the comet's water. Probably they are made of carbon fibre extracted from the comets, giving it a shiny black streamlined look. They change orbit slowly but on a large time scale. When they approach a suitable comet, they grasp on it with long arms (hundred of metres to several kilometres) terminated with large rackets. When this is done, they activate their ion thruster until the captured body is on an impact orbit. Then the comclast has to free itself to escape the impact and seek for another body to capture.
(Permalink) Terraforming Venus is generally regarded as impossible, due to its red hot temperature and huge ocean of carbon dioxide. However it may finally involve less material moving than Mars, since air, water and organic matter are already on Venus in fair good quantities.
The idea is to bring an umbrella to Venus, able of deflecting most part of the sunlight here. An iron asteroid can do this, with a sun-powered factory chipping it in thin sheets in Venusian orbit. The sheets rotate at random, but by average they still provide a efficient shield. Other scientists propose installing the shield in the L1 Lagrange point, where they do not need to move. But here they are not stable.
What would happen if Venus cools off? A lots of things, because its low atmosphere probably contain hazes of complex chemicals such as sulphides, or even molten metals. But the main idea is that the water forms an ocean. That would still be not enough for making Venus inhabitable, because there would be sulphuric acid in the ocean, and still 90 bars of carbon dioxide in the air.
What needs to happen at this time is that these two meet enough alkali metals (calcium, sodium, potassium, magnesium), so that they form sulphates (plaster) and limestone. This is quite possible, since the total quantity of free carbon dioxide on Venus is not much more than the total carbon dioxide trapped in limestone on Earth! But it will need millions of years, since the release of these metals happens only slowly, with erosion.
Added June 15, 2016: But precisely, there is very few water on Venus. In the beginning, the atmosphere of Venus was much like Earth's atmosphere, with even a blue sky. But the higher nitrogen pressure, combined with more solar heat, probably forbade the few water to reach enough partial pressure to condensate. Therefore, water could never erode the ground, and the above processes could never happen, allowing carbon dioxide to accumulate and locking the planet in a terrible greenhouse effect.
(Permalink) Moving Mars and Venus to the Earth orbit would allow them both to have much better living conditions. But this seems such a far-fetched project that it is usually deemed impossible.
However there is a workable solution: when a space probe uses a planet for gravitational assistance, it steals a bit of its speed. For today probes this amount is insignificant, but the repeated action of larger bodies may bring effective results. So the idea is to drive an asteroid on such an orbit that it regularly crosses near the two planets, stealing energy to one to boost the other. (Since Mars is much smaller than Venus, Jupiter or Mercury may also be involved to bring balance).
This system will anyway have a very useful application: pulling the Earth itself farther from the Sun, so that it keeps a cool enough climate. Without this, photosynthesis may become impossible on Earth before one billion years, while we still have 4 billions of sun light to enjoy.
The speed and effectiveness of such a project depends on the quantity and mass of bodies swapping the energy from one orbit to the other. It may anyway take millions of years, but this is not a problem for ego-free psychoeducated people (chapter V-12). The lesser project, taking Earth further, is required anyway, but we have well enough time for this.
The main danger however with moving planets is to bring them on unstable orbits, where they will have to be monitored forever (forcing our descendants to keep high technology active). If this happens, for instance a close encounter between Earth and Venus may pull Earth on a very unpractical elliptic orbit, with freezing winters and sterilizing hot summers. A direct collision would even be possible. Given that the minimum collision speed is the sum of the two escape velocities, such collisions are likely to vaporize and shatter both planets. Even a far away collision, say between Venus and Mercury, would create enough dust to shadow Earth for ten of thousand years, not accounting with the meteorites shower.
And what would be the best configuration? The most seducing is most probably to pull Mars and Venus on Earth's Lagrange point. Unfortunately we do not know if such a configuration is stable in the long run. Probably not. Another configuration is likely more stable: putting Mars in orbit around Venus, and bringing the pair in one of the Lagrange points of Earth. Or even a 4 bodies configuration, with Venus, Mars and the Moon in orbit around Earth. Probably too dangerous to try, but a fantastic vision in our night sky... And terrible tides.
(Permalink) Assuming the Moon is not declared a reservation zone, it is the only planet where mining may be worth the effort. This is because the low gravity allows for a simple electromagnetic gun to send the mined metals on Earth, using the abundant solar electricity. But still for high cost metals only. If there are any on the Moon: as it is entirely volcanic, it lacks the geological processes which formed most of our mines on Earth. So that Moon mines may probably just not exist!
There is an exception, however, as large uranium mines has been identified on the Moon. Large enough to be visible to the naked eye: the rock of some of the moon «oceans» is highly enriched in uranium! It is the heat of this uranium, precisely, which drove these huge volcanic eruptions which formed the «mares».
Of course this uranium cannot be sent on Earth, because of the danger of the nuclear industry. But it may be an unique opportunity for fuelling fission reactors interstellar probes! Because we can do fission probes, while fusion probes are not demonstrated.
(Permalink) Many has been said on interstellar travel: propulsion methods, inhabited spaceships, etc.
However most people are missing one point: unless some unforeseen discovery, interstellar travel is bound to last for centuries, see millions of years. There is no evidence, right on the contrary, that Star Wars-style spaceships can exist and allow for even slightly faster interstellar travels.
For an automatic space probe, this may still work, and it is not unlikely that in a close future (maybe even in the 21th century) we send automatic space probes to our closest space neighbours. Such an undertaking is also economically feasible, if there is an international will to do so.
Such machines will need to use nuclear energy. We know how to use fission for this purpose, but fission is hampered by the scarcity of resources in fissile materials outside of Earth. Fusion can in theory feed on hydrogen about everywhere, but it is not sure that we can do fusion reactors, despite the vast amount of research on it.
So that automatic interstellar travel is possible with the fission technologies we have in hand, but only fusion would allow it to scale up.
Interstellar travel for carrying persons is another story. Indeed, even for reaching the closest star, several generations will have to live in the spaceship... admitting that children can grow normally in weightlessness, which is very unlikely. This requires a very heavy life support system and huge radiation shield. But it also poses severe human threats. Most likely, the crew may fight or revolt, to the point of stopping supporting the spaceship and even destroying it. Should they arrive, their motives will be entirely different of the senders, and they will develop a civilisation of their own. Which may be better than on Earth... or much worse.
My contribution to the bargain is original: we do not actually need people travelling in the spaceship (more all the animals and seeds). It is just enough to send DNA code under the form of computer data. A DNA Arch! ©(note 93 on the use of ©. I claim paternity on this name, from February 9, 2015). Once arrived in a suitable environment, nanorobots can translate this code into living DNA again, in order to reconstitute a full living environment with plants, bacteria and everything needed for a fully working ecosystem. (Unless unknown precedence, I claim the paternity of this idea, that I first published in my Likpas webcomic in 2013, see «the MOTHER» story (better to read first the other stories, for the suspense))
This is by the way an unique occasion to create a perfect ecosystem, free of any disease, poisonous things, predators, invading species, a world without a single thorn, where we can walk naked and barefoot everywhere, with no other tools than our hands, nose and mouth...
After a first ecosystem is completed and large enough to support an Human community, the robots will just have to «synthetize» Humans. This is the most tricky part, as babies and children have a vital need of parents for their education. Humans without any just die!
A possible solution is humanoid robots as parents. But even so, the first generation is likely to grow idiot. But as soon as they can reach adulthood, they can raise a better second generation, giving it kindness, while the intellectual education is ensured by the robots.
But a process entirely led by robots suffers serious flaws: when a second generation of children has on one side idiot parents, but real, loving and sensual, and on the other side smart educators, but mechanical, then it will be very difficult for them to choose the good... Worse, the robots have a crucial decision to take: keeping control on evil children to avoid them creating their own power, or relinquishing their robot power when a psychoeducated community appears. But precisely, how a robot can appreciate evil or psychoeducated? The risk is in both way: they let a dictator free, or they become dictators themselves.
The solution is probably what I explain in the end of chapter V-18: electronic brains able of free will, so that they can be invested by a real consciousness. When they do, they can lead the newborn people against evil, and know when the robots can relinquish their control.
There is another solution, which looks very science-fiction, but which technical possibility appeared precisely today (January 2015): 3D printers able of creating human bodies, knitting them cell by cell. In this way they can bypass the education stage, and create directly psychoeducated brains, assembling them neurone per neurone! They can even use as a template the most gifted brains, high artists, heart people, or even highly evolved spiritual beings, as soon as they die naturally and the connectome (note 88) of their brain can be measured. This process looks much safer than the random education process. We need to keep it for special occasions, though, like here, or for repairing mutilations.
This idea makes that colonisation of space may be technically easier than imagined (much easier anyway than the inhabited spaceship method). But in any case, psychoeducation appears as an indispensable ingredient for actual success. Hence the relevance of discussing this in an essay on the Fermi paradox: only psychoeducated species can leave their planets.
And reciprocally, only then can come on Earth.
(Permalink) This is a very close prospect, within some years.
It is now highly sure that Europa has an ocean, hidden under only some kilometres of ice. The main question however is: does this ocean harbours life? It may, since nothing opposed the evolution of life in this 4 billions years old stable environment (Perhaps too stable, it lacks the bottlenecks which favoured evolution on Earth). In more, we have an abundant energy source, with (most likely) lot of sulphur from volcanoes. But alas this sulphur may have rendered this ocean highly acidic, forbidding life. Whatever, the only way to know is to send a probe in this ocean. (Added in June 2021: this water is very clean, after a study using the Hubble telescope. Which is encouraging, for the search of life.)
Not so simple, and several projects have been envisioned, like a powerful radioactive source melting the ice until it reaches the free water. This entails a lot of difficulties, though, like soft landing a heavy charge, winding a long cable, resisting the harsh radiation environment on the surface of Europa, not to speak of the concern of launching an important radiation hazard through the Earth atmosphere.
However there is a simpler trick: in many places, the ice crust of Europa has been upturned by some violent processes, which broke it and allowed water from under to arrive at the surface, and freeze. This new ice is easily recognizable with its pink colour. Is this colour from acid, dissolved salts, or some form of bacteria? We do not need to dig all the way through the ice to know, as it is just here at the surface.
The plan I propose is to launch, from Earth, a small probe, but at high speed, so that it reaches Europa directly. It would use advanced computer navigation systems to reach a very precise target (a pink spot), using a small cruise/guidance stage with a xenon engine. The final approach of Europa would be designed to minimize the relative speed (eventually using gravitational assistance from the outer moons). Then the probe would not decelerate, but hit the surface like a shell, and bury itself into the pink ice. Such a brutal manoeuvre has a precise purpose: the probe reaches a depth of some metres, where it will be sheltered from the intense radiations in Europa. In the same stroke, it will also reach materials which were sheltered from the radiations. At last, this probe would not need a descent rocket, hence its small size and low cost.
Here, it would activate a battery, and performs analysis and microscopic imaging of whatever it finds. Then it would have some hours to send the results by radio, to a relay spaceship in the Jovian system.
With some haste, this low cost mission could reach its target while Juno is still around for performing the relay tasks.
A fascinating aspect of this mission is that, from its very low energy budget, it will need to be entirely automatic, and totally silent and stealth in radio, starting to emit only for Juno to find it and performs its relay role.
And the low budget allows it to be performed by amateur funding.
(Permalink) Having a probe on the ground of Venus would help solving many crucial questions. Especially why Venus has its climate: lack of water, lack of alcaline metals able of fixing the carbon dioxide into limestone? Was there a magnetic field, and when and why it disappeared? Was water present in ancient times, forming specific rocks like granite or sedimentary rocks? Are the mountain ranges remnants of a plates tectonics? Finding a single fossil on a Venus mountain would be a fantastic breakthrough.
In more, Venus has a fantastic advantage: it is very easy to fly, thanks to the very dense atmosphere. A some metres long steam-inflated zeppelin is able of carrying a full probe, allowing it to fly for years and sample a large portion of the Venus surface. So that only one lander may be able of solving nearby all the science questions about Venus.
The obvious inconvenience, though, is the temperature. And thermodynamics laws forbid the use of some kind of refrigeration: it would consume an awful lot of power. So that any permanent probe has to be entirely designed to be able of working at the local temperature.
We still have many metals or ceramics having interesting mechanical properties at 450°C. However the worse problem is not temperature: it is the chemistry of the Venus atmosphere. And what we know is scary: highly acidic and oxidizing. The Venera experience even showed liquids of unknown composition, and other bizarre phenomena. We may find some unexpected chemicals in the lower atmosphere, corroding the probe hull, infiltrating joints with dangerous liquids, or accumulating solid crusts: fluorydric acid, sulphur, SO3, hydrogen sulphide, molten sulphides, rock dust, molten metals, etc. The list of materials able of withstanding such a potion at 450°C is very short.
Evaluation of Venusian air
The above problem makes that, before designing a lander, we need to send some suicide mission on the Venus ground, able of performing an extensive and complete chemical analysis of the air, aerosol and dust, in a very short time, before it burns. On the other hand, such a mission may be cheap, with still and interesting science output. It could even be an amateur mission. At least it would be infinitely more useful than sending twit singers and eccentric businessmen in orbit.
Added April 2018: Instead of a short lived suicide mission, it would be better to entrust these atmospheric experiments to a static lander. This is because we can add to it a seismometer and an angular momentum experiment. This would be an excellent scientific complement to the flying lander, with indispensable experiments it cannot provide. But having no opening, it would work even with the today uncertainties on atmospheric composition, so that it can be a preliminary mission for the flying rover.
Since probably very few materials will be able to withstand the Venusian air, we need a thorough streamlining and sealing of the probe, with only the needed apertures. Unfortunately, no material like rubber can work here, but we may have some silanes, elastic metal rings, etc. Anyway we need to assume that any seal shall leak, and build the probe in such a way that these leaks lead nowhere.
Electric conductors (transformers and motors)
With temperature, conductors will become significantly more resistive, forcing the use of larger wires, and even silver in motors and transformers. So they will have to be bigger, or use higher frequencies.
Any plastics or varnishe s have to be ruled out. Many insulators are still effective at 450°C, but very few are supple. This may force the use of guipure for wiring, as in the beginning of the electric age, and special designs alternating layers of metal and of oxides, for windings.
Magnetic materials (transformers and motors)
Fortunately, many materials have high enough Curie point, where their properties may even be better than on Earth.
Of course common oils are ruled out, seeming to make lubricants impossible. However a lubricant does not necessarily have to be «oily»: it needs to have a defined viscosity, while adhering to the material to lubricate. This is how a lubricant forms a film between metal surfaces, allowing them to slip easily without damage. A lot of molten salts can do this, even if we need to carefully set their composition for adjusting viscosity and preventing corrosion.
No common semiconductor works at 450°C. However, there are a lot of ongoing researches on electronics able of running at such high temperatures, with some advances toward this goal. A first path is identifying semiconductors operating in this range (Added June 2021: gallium nitride could work). A second path is using some «integrated circuits tubes», miniaturized electron tubes using cold spindle cathodes and integrated circuits technology. We may even not need heating, since the cathode is close to the required temperature. However we may have thermoionic effects making electron tubes impossible. A third path is sub-micron scale electrostatic relays, able of commuting at much higher speeds than the classical relays, and insensitive to temperature.
This is the most problematic part, since very few energy is available on the Venus ground: few solar light arrives here, and no wind, no water, no chemical energy sources. It is even not sure that a nuclear RTG source works here. It would certainly withstand the temperature, but we do not know thermocouples able of working here. Maybe a thermoionic generator will work instead. So the only solution would be that the probe is attached to a balloon at a much higher altitude, for instance 40kms, where it can pick the permanent strong winds here. This balloon then acts as a sail, providing the propulsion of the probe, for free, all around the planet. The probe can then have a wind turbine to pick this energy. Without need for propulsion, the electric power requirements can fall under 100 watts.
Pneumatic or hydraulic.
In Earth condition, the relative advantages and inconveniences of electricity, pneumatic or hydraulic make that each has a defined domain of applications. Especially pneumatic is limited by the thermodynamic efficiency of a pneumatic engine: good with a low ratio of pressure between the input and the output, it degrades quickly when this ratio increases. This makes than on Earth pneumatic systems seldom go beyond 6 bars (6/1 ratio between input and atmospheric output), making pneumatic jacks bulky. The efficiency of hydraulic systems does not depend on pressure, allowing for much higher pressure and much more compact designs. However they are still limited in pressure by the loss of elasticity of the gasses used to keep the tanks pressurised. In Venus conditions, though, the previous 6 ratio in pneumatic systems, applied to the 90 bars atmosphere, allows for a Venusian pneumatic system to work efficiently with pressures comparable to hydraulics. This makes them as much compact, while being simpler and more reliable. For this reason, on a Venusian probe pneumatic actuators may be preferred to the weakened electric actuators, against the custom of using only electric actuators in space probes.
Hydrogen and helium are ruled out, as most materials would let them leak at 450°C. Even with a storage, this would limit the lifespan of the balloon to some mere weeks. Fortunately, in a carbon dioxide atmosphere, many gasses unsuitable on Earth become safe and efficient balloon gasses, like nitrogen, oxygen, neon, argon, methane, etc. But the most interesting seems water steam. Nitrogen, argon and steam can be extracted from the atmosphere, ensuring a limitless life for the gas supply. Only problem is the energy required.
Luckily, we have batteries operating at this range of temperature: metal-sulphur batteries, and some molten salt batteries. Fuel cells work too.
Of course we think at communication with Earth. We note that the higher balloon can too have a wind mill, operating in a fast wind. So we have a high energy source here, much higher than in most space missions. This allows for direct emission to Earth, without a relay satellite. We can also place a large gain antenna, free to rotate, inside the balloon.
We also need to know exactly the position of the probe. For this a GPS needs three satellites in orbit. But there are other solutions without satellites.
The double balloon architecture allows for the probe to follow the upper atmosphere winds. However it is not known if this really allows for exploring the whole planet: the probe may remain stuck in a given latitude range, or swirl out of control without ever reaching any interesting point. However, if we can orient the upper balloon and use it as a sail for obtaining different points of sail, then we can sail everywhere.
Winding the linking cable also allows to change the altitude of the lower balloon, for exploring the mountain ranges. Lowering it acts as an anchor.
As shown by the Venera probes, the visibility is short in visible light. But it is better in infrared. Radars would work well, and sonars much better than in Earth's atmosphere, from the dense air. Also, since the sound goes far and is well coupled, a microphone somewhere on the tether cable may pick a lot of interesting things.
Main science experiments, besides photography, would be rock analysis, isotopic analysis and isotopic datation. Research of microscopic fossils or organic residues (coal, oil) would make sense too, in the mountain ranges. A magnetometer would allow to find fossil magnetic fields. A pause on the surface may allow for a measurement of Venus's moment or inertia, while also operating a seismometer. But these two experiments would work better with a static lander.
Analysing and dating the vast plains will give most answers on the general Venusian mysteries. However, once enough samples gathered, there is no point to continue here, and it will be much more interesting to explore the mountains. It is not known today how these mountains were formed, and why they are remaining high despite the general softened Venusian crust. Are they the result of some convection, or are they the remnants of less dense continents formed when Venus had a plate tectonic? They also are the only place where water geology and former forms of life may have left any observable trace. So any science mission may well spend years exploring them in details. Surprises may be rare, but so priceless that it is worth waiting.
(Permalink) Due to Venus having roughly the same gravity than Earth, a sample return mission is very difficult. In theory, we need about the same rocket than the one used on Earth to launch the probe. Add to this that this rocket has to go through a much thicker atmosphere, and sustain the hellish ground temperature: such a mission is, to say the least, extremely difficult.
However there is a better way. A small sample capsule can raise in the upper atmosphere using a balloon, or the tether cable of our Venus lander. Once up, it can find another balloon, containing a small rocket. This small rocket is then able of lifting the very small sample capsule into space. Here, it can meet a relay satellite, or even go direct to Earth, since the useful load is less than the kilog.
Contrarily to Mars samples, Venus samples pose no biological hazard, so that they need no complicated procedure to approach Earth.
(Permalink) This is much simpler than for Venus, since Mars has few atmosphere and a much lesser gravity. The huge problem however is the biological hazard: even if the chances look low today, the consequences of a contamination of Earth by some dangerous Martian bacteria cannot be ignored.
My contribution to this puzzle is to send the return rocket on a trajectory close to the Moon, so that it is captured in Earth orbit. A light braking is required at this moment, to lower the apogee so that it does not meet the Moon again, while the perigee is low enough to be reached by a space station containing extensive lab instruments.
(Permalink) Human exploration of the Moon has been abandoned because of its high cost, not in proportion of the expected science return. There is not a lack of science puzzles still awaiting us up there, though. However they are scattered far away from each other, and would need many missions, making the cost too high.
However the progress of rovers would allow for a single rover able of running many years and tread large distances, including on the hidden side. In more, today largest rockets would allow to land 10 or 20 tons on the Moon, rather than a toy like the first Martian rovers.
If no human presence is required to operate it, it may still rendez-vous with manned landers, for bringing new instruments or to recover samples.
We need large solar panels, to produce the 10-20 kilowatts required for a fast driving on the rough Moon surface. The problem with these is mainly dust, this terribly abrasive moon dust, chemically activated by ultraviolet light and electrostatic charges to stick on everything. Some lab studies are required to understand its properties, and prevent it to stick on the panels surface. Wipers may be inefficient, and they will quickly wear the panels surface anyway. Electrostatic contact-less wipers have to be considered, or diamond layers on the surface.
Wheels and suspension
We need large steel wheels, not slippers like Curiosity (sorry, it was a serious mistake to send a machine able of operating 80 years, with aluminium wheels which are already seriously damaged after only one year). These wheels may need to be replaced, using the telemanipulator arm. Also, they are mounted on long legs. Reasons for this are:
- Maintaining the balance of the rover on slopes, while carrying large solar panels and other protruding parts.
- Better absorbing shocks in fast driving
- Using active damping, recovering the energy usually wasted in dampers.
- When one of these arms is stuck or broken, it can be pulled upward, or severed, without impeding driving. It can be replaced later.
General body shape
The general body has a bus structure and a remote-controlled arm to clips instruments in place. It can also clips the wheel legs, an even an inhabitable cabin.
With a 3 seconds loop, the vehicle and its tools can still be remote-controlled in real time. However high speed driving is problematic. We can use the stereo cameras and autonomous driving software which were developed for the Mars rovers. However, the Moon surface has potholes everywhere, and the lack of contrast makes them invisible before we are very close.
The solution I propose is to use a lidar, mounted on an antenna in the front end. This provides a much better 3D map of the terrain, without the many approximations used for making it from stereo 2D views. In more, it provides exact distances even with zero contrast. Zero contrast easily hides a pothole to stereo cameras, but not to a lidar looking from above. At a pinch, the Lidar can mark a place where it cannot see, so that the driver avoids it.
Added March 16, 2017:
(Permalink) The idea here is to destroy or deflect dangerous asteroids or comets, which may otherwise pose a threat on countries, continents, or even on the whole Earth. Many methods were proposed:
-The most dangerous: use atom bombs to blast the threatening body. The result would be the debris of the asteroid continuing their path toward Earth, bringing more destruction, not to mention the added radioactivity.
-The most unrealistic: bringing a spaceship at some metres of an asteroid, in order to attract it with the gravitation of the ship. Elegant, but just pushing the asteroid with the same spaceship would be billions times more efficient.
-The most realistic looking today with our technology, is to attach a ion engine to asteroids, in order to deflect them. Since the effect of a deflection of an asteroid increase exponentially with time, event extremely small deflections can be useful. Even big asteroids will end up with noticeable changes in orbit. Such a ion engine will have to use solar energy, and extract reaction mass from the asteroid itself. In doing so, it can operate continuously for tens of years, without being limited by a propellant load.
-What I propose here (I found this in March 2017, but while checking I found it is known since 1995) is a drastic bettering of the previous: once we have a spaceship with a solar panel on an asteroid, then at equal panel size, it can produce a much larger impulse with simply firing a laser to the asteroid surface, vaporising matter from it. This method brings together the extraction of reaction mass and its acceleration, in a single operation, without the hassle of extracting, purifying and processing materials to a ion beam. The spaceship even not have to land on the asteroid, it can shoot at it from a safe distance.
A serious problem is accuracy: errors in the estimation on the future position of an asteroid also increase exponentially with time, so that for today (2017) there is no way to predict any useful deflection vector beyond some years. Worse, a wrong vector may actually cause a collision, instead of avoiding it! This makes that today the most useful development direction of the asteroid protection network is larger and more numerous telescopes, for tracking asteroids farther and with a much better accuracy than today. We also need vantage points away from Earth, in order to create a much larger parallax and drastically increase the accuracy of orbits determination. This is the purpose of the projected Sentinel Space Telescope.
Yet any of these methods suffer some serious drawbacks: we need one spaceship per dangerous asteroid. Worse, years are needed to send a spaceship in any target. This does not work in the case of a threat suddenly appearing from outer space, with only a some months warning.
The VishvaKunta project © (note 93 on the use of ©) addresses these drawbacks in the worse scenario. This name comes from a novel I wrote, describing the project (precedence claimed for March 2017). In a nutshell, instead of bringing a laser on the asteroid or comet, we shoot at it from afar. Same result, but we don't need the long travel to the object! The travel time is reduced to some tens of minutes. This really allows to cope with surprise objects, as we don't need to send a spaceship to them.
My first ideas were an electric gun, or a particle accelerator. However the transferred impulse would be very weak, unless we have an impractically large solar panel of a hundred of kilometres. In more particles would be dispersed in flight, for several reasons.
Only a laser beam can remain focused enough over the hundreds of millions of kilometres of travel. But if so, it can vaporize the surface of the intruding body, and in this way we get a sizeable reaction force, using material from the object itself! After all, comets have measurable change in orbit, from the mere sun light. So that a laser should work much better.
We still need a kilometres-wide solar panel, and this would be the main limiting factor, both in price and in efficiency. The idea is then to concentrate the sun energy otherwise.
This is possible with a solar-pumped laser: the sun light directly excites a laser gas, to produce a laser beam. In this way we do not need solar panels, and the concentrator can be a mere balloon, with a reflective coating to form a parabolic mirror. Cheaper and much lighter than any solar panel, for similar size.
The VishvaKunta Space Station would be formed of several parts:
-An external balloon, with reflective coating on one side. This balloon is not kept in shape with a gas, because it would be quickly punctured by space dust. Instead we use electrostatic forces, or mechanical forces in the material itself. The two main designs are a sphere (parabolic concentrator) or a sausage (cylindro-parabolic concentrator).
-An excitation laser.
-A beam spreading optics. We need this, as the focus of the mirror is not excellent, and the active zone may spread over metres and even tens of metres in diameter. In more the laser gas is at low pressure, which limits its efficiency per volume.
-An inner tube shaped balloon, containing the laser gas. Here it is protected from space dust. In both designs, it goes all through the external balloon, through the focus point or along the focus line.
-An optical window to get the beam out of the two balloons.
-An orientation mirror, to send the beam toward the target. Orientation mirror, beam spreading mirror and optical window are the weak points, needing a very high accuracy in order to keep the beam focused over a high distance. This is, I think, the most delicate point.
-Instead of reaction wheels, which would be overwhelmingly heavy, we can have light but very long antennas for keeping the station oriented toward the sun despite the yearly change of orientation.
-The laser wavelength must be in the infrared, to be unable to go through Earth's atmosphere, and avoid the system to be subverted into a war use.
-The laser gas will probably be a complex mixture, containing fluorescent molecules in order to capture the highest energy photons efficiently.
-Pre-studies about solar-pumped lasers proposed a iodine compound lasing at 1.31 micrometer. The efficiency of this laser material is 25%, but the fraction of solar light effectively used was very weak, making the overall efficiency only 0.6%. Clearly the main research must go toward better laser gasses catching more sun light, even before optimising the laser efficiency itself.
-The inner tube needs to be made of some supple sapphire fibres mesh, to withstand the heat. This is a limiting factor, and a cause to have this tube larger. But this also increases the size of the optical windows.
These contradictory requirements make difficult to predict the best design without a complete engineering study and tests. It is also too difficult for this modest study to assess which would be the optimal geometry for the balloon and concentrator. This will also depend on cost considerations on the various methods at the time the project will be built.
Added on April 26, 2020: Ah, if we had had the Vishvakunta project, we could have tested 'oumuamua in a few dozen minutes, including measuring its mass and composition.
This is one of the numerous costs of ignoring my work. Sorry, my intent was to help. Being ignored is not my problem, not even my thing.
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