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Russian Space Program: News & Discussion #3
Scorpius- Posts : 1574
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GarryB, magnumcromagnon, kvs, thegopnik, TMA1 and Nomad5891 like this post
Nomad5891- Posts : 62
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Great pics Scorpius. Any idea what the EVA was for or just some sort of training?
About space mining being hollywodd bullshit, well...let me put it this way...if you were to explain in general terms the core idea behind graphene nanotubes to a first half XX century country government, the reaction would be the same - oh it is not possible, oh it is not feasible, oh it is too expensive, we do not need it.
And they woud be right, actually.
Sure we do not have the technology, the tools, or maybe even the need for space mining today, but I am pretty sure it will be pionered in 25-30 years and then fully exploited by end of century.
I guess the way to go would be to process valuable asteroids to some sort of high density metalic powder in space, and then use it by autonomous drones for 3d printing structures in orbit or the Moon or Mars.
I agree Earth has too high gravitanional pull and too thick of an atmosphere that make constant transport up and down to space too complex, costy and dangerous.
About space mining being hollywodd bullshit, well...let me put it this way...if you were to explain in general terms the core idea behind graphene nanotubes to a first half XX century country government, the reaction would be the same - oh it is not possible, oh it is not feasible, oh it is too expensive, we do not need it.
And they woud be right, actually.
Sure we do not have the technology, the tools, or maybe even the need for space mining today, but I am pretty sure it will be pionered in 25-30 years and then fully exploited by end of century.
I guess the way to go would be to process valuable asteroids to some sort of high density metalic powder in space, and then use it by autonomous drones for 3d printing structures in orbit or the Moon or Mars.
I agree Earth has too high gravitanional pull and too thick of an atmosphere that make constant transport up and down to space too complex, costy and dangerous.
Big_Gazza- Posts : 4895
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Nomad5891 wrote:I agree Earth has too high gravitanional pull and too thick of an atmosphere that make constant transport up and down to space too complex, costy and dangerous.
The costs have nothing to do with Earths gravity but simply the deltaV required to move recovered materials from one orbit (ie the asteroid) to where it is needed (eg earth, moon, orbital station).
This is basic physics and isn't going to go away. It doesn't really matter what form the recovered materials take (raw materials, finished products), its only about mass. the greater the mass, the greater the energy requirement and the larger the transportation system needed to move it.
Nomad5891- Posts : 62
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Big_Gazza wrote:Nomad5891 wrote:I agree Earth has too high gravitanional pull and too thick of an atmosphere that make constant transport up and down to space too complex, costy and dangerous.
The costs have nothing to do with Earths gravity but simply the deltaV required to move recovered materials from one orbit (ie the asteroid) to where it is needed (eg earth, moon, orbital station).
This is basic physics and isn't going to go away. It doesn't really matter what form the recovered materials take (raw materials, finished products), its only about mass. the greater the mass, the greater the energy requirement and the larger the transportation system needed to move it.
1) Everything in nature, including it seems human economics move arround cost/difficulty, always trying to achieve the easiest/less costy/less complex solution.
2) In terms of difficulty, therefor cost it is much easier and less complex to safely land same mass of anything to the Moon than to Earth.
3) How is ammount of energy delivered depending on actual size of "power plant"? A steam engine delivers much less energy than a diesel engine per size unit. So actually you would obtain more energy from smaller diesel engine than larger steam engine. It is much, much more complex than that.
4) I think we are far from understanding how this universe works, lacking full understanding of mundane phenomenon as gravity, so stating that something is basic physics means very little.
GarryB- Posts : 40537
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A small, 10 km asteroid contian more gold, platinium, iridium and so on than the top ten km crust of earth.
There are certainly likely to be asteroids with valuable materials in them, but just as common if not more so are icy comets and rocky rubble piles of little to no value at all.
There are asteroids out there that composed from pure, high quality iron-nickel alloy.
The energy needed to change the orbit of such objects is very similar to the energy needed to smash them into tiny pieces... not to mention the distances involved.
Possible to make/do industrial processes on never seen scale, with very light and simple tools.
Construction in orbit is notoriously problematic with tens of thousands of tools lost in space in orbit smashing in to things, because you let go for a second and it just floats away. Once out of reach it is gone forever and a new threat to everything in orbit.
Easy job with a pure metal asteroid, and with hair thick solar mirror.
Out at the orbit of these asteroids in the asteroid belt that solar mirror would need to be enormous... at the oort cloud no size would be big enough to be effective... would be like trying to use a solar furnace with moonlight.
Gather a few asteroids together, start building a scaffolding and production site around them, and use their materials as needed
But that is the problem... decent sized asteroids are enormous distances apart and the heavy ones would require enormous amounts of energy to shift.
Some Asteroids you could probably tunnel in to to create a living space for workers or drone robot mining equipment... but doing anything but fabricating ingots of various materials and launching them on a trajectory back to earth would not really make a lot of sense... and launching loads to earth would effect the object itself by pushing it slightly further away...
Rubbish and detritis could be launched in the opposite direction at enormous speed to effectively use the rubbish to accelerate the "mine" closer to earth... but it would really only make sense and therefore be least effective on the very biggest objects with no atmosphere like the earths moon...
Then you can simply maneuver the structure to where you want it, avoiding any planet's tidal effects
Mass is the killer though... to move it you need enormous levels of energy which would be expensive... unless you had smart tunneling mine machines that hunted down and dug out the most valuable materials and formed ingots and launched them on a trajectory towards earth where they could be captured and returned to earth.
But I have not seen any
demonstration where Pluto sits in a belt of debris. So to me it looks like games with definitions. One can hardly expect Pluto
to clear out the Kuiper belt.
If that were the definition then Plutos orbit crosses that of Neptune, so if Pluto isn't a planet because it hasn't gobbled up Neptune then Neptune isn't a planet either because Pluto and Charon remain in part of its orbit...
Titan is a cold moon of Saturn that has liquid hydrocrabons acting as a substitute water cycle.
For a long time Titan was considered plan B when our sun expands as a supergiant as it gets older... but the problem is that if the sun does expand then Titan will warm up and lose its thick atmosphere which it currently keeps because it is so cold.
2) In terms of difficulty, therefor cost it is much easier and less complex to safely land same mass of anything to the Moon than to Earth.
Actually on Earth or Mars or Venus there is an atmosphere that can be used to slow the speed of the payload with aerodynamic drag... either wing or parachute or gas bag... on the moon you need to burn fuel or just impact the product into the ground... large ingots of iron or nickel is hardly going to be destroyed by impacting the surface.... dig em up and use them on the moon to build things...
A 1,000 ton slab of titanium directed at earth to hit somewhere on the ground... it will be hot but should be recoverable...
I think we are far from understanding how this universe works, lacking full understanding of mundane phenomenon as gravity, so stating that something is basic physics means very little.
Basic physics in the sense that a trillion tons of iron that form part of an object 30km across.... you could cut off chunks but the energy needed to take those chunks and launch them towards earth from the asteroid belt or further out make taking the entire object impractical... at the basic simple physics level.
Kiko- Posts : 3887
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Russian Cosmonauts to Test New Shielding Material for Radiation Protection, Roscosmos Says
MOSCOW (Sputnik) - An award-winning composite material that has proven effective against radiation in nuclear submarines will be sent to the orbital outpost for further testing this year, the Russian space agency said on Monday.
"Space is known for its elevated radiation levels... The invention has already been tested in nuclear subs. If the space experiment proves to be equally successful the material will be used to make garments for cosmonauts and cabin lining," he said.
https://sputniknews.com/russia/202102081082016801-russian-cosmonauts-to-test-new-shielding-material-for-radiation-protection-roscosmos-says/
MOSCOW (Sputnik) - An award-winning composite material that has proven effective against radiation in nuclear submarines will be sent to the orbital outpost for further testing this year, the Russian space agency said on Monday.
"Space is known for its elevated radiation levels... The invention has already been tested in nuclear subs. If the space experiment proves to be equally successful the material will be used to make garments for cosmonauts and cabin lining," he said.
https://sputniknews.com/russia/202102081082016801-russian-cosmonauts-to-test-new-shielding-material-for-radiation-protection-roscosmos-says/
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Scorpius- Posts : 1574
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In the photo, in general, the goal of the spacewalk is visible. These photos are from 2018, when the astronauts had to perform an operation to find an external hole that caused the depressurization of the Soyuz spacecraft. By the way, this was the first operation of this level of complexity on a spaceship in history.Nomad5891 wrote:Great pics Scorpius. Any idea what the EVA was for or just some sort of training?
Singular_Transform- Posts : 1032
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- Post n°683
Re: Russian Space Program: News & Discussion #3
Singular_Transform Mon Feb 08, 2021 5:55 pm
In the space the distance and energy requirement not the same .GarryB wrote:
There are certainly likely to be asteroids with valuable materials in them, but just as common if not more so are icy comets and rocky rubble piles of little to no value at all.
The energy needed to change the orbit of such objects is very similar to the energy needed to smash them into tiny pieces... not to mention the distances involved.
Construction in orbit is notoriously problematic with tens of thousands of tools lost in space in orbit smashing in to things, because you let go for a second and it just floats away. Once out of reach it is gone forever and a new threat to everything in orbit.
Out at the orbit of these asteroids in the asteroid belt that solar mirror would need to be enormous... at the oort cloud no size would be big enough to be effective... would be like trying to use a solar furnace with moonlight.
But that is the problem... decent sized asteroids are enormous distances apart and the heavy ones would require enormous amounts of energy to shift.
In very long time with small energy huge masses can be moved.
Example , million tons of asteroid can be captured to the Earth Langrange 4/5 with small energy - it will take lot of time, but not that much.
Solar furnance can be as thick as the finest foil.Each square meter of it will generate 0,5-1,4 kw 24/7 between mars-earth orbit.
There are many asteroid around the earth orbit as well, closer than the surface of the moon, accessible by ion thrusters.
And important, the difficulty of droped tools and things like that is due to the high gravitational shear in LEO.
In L4/5, or in Sun orbit that doesn't exist - the shear (tidal force) neglible there .
Due to the high shear force a big and light solar furnance would disintegrate in low/medium orbit.Hence the usage of solar panels.
https://echo.jpl.nasa.gov/~lance/delta_v/delta_v.rendezvous.html
List of near Earth asteroids by delta V .
Reference, the surface of Moon is 6km/sec deltaV away from LEO, Mars is only 3.8 km/sec deltaV away with aerobrake, but that is one way,and afterwards the get out from the surface is impossible with ion thrusters.
There are 3600 known asteroid closer than the surface of Moon.
limb- Posts : 1550
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Big_Gazza wrote:limb wrote:Then what kind of new manned spacecraft trips and tech or planetary colonies can we actually expect in the next 50-70 years?
Regarding asteroids, what about mining iridium or beryllium?
What makes it impossible to use some kind of charge neutralizing tech to prevent regolith sticking to surfaces.? Its hard to imagine that preventing dust sticking is more complex than designing HGVs.
We need to identify asteroids that have useful concentrations of the valuable materials for which we have great need. Not sure what that might be however, and i'd suggest that it makes more sense to extract rare materials from oceanic seawater rather than trying to prospect orbiting rocks out past Mars.
IMHO manned space activities will inevitably be driven by the desire to explore (and wave the flag) rather than commercial considerations.
Not sure about how we deal with the dust issue on lunar bases. Rigorous segregation of dirty materials (such as EVA suits) from habitable spaces is probably the main focus. Suits would ideally be designed to include an integral airlock arrangement allowing the occupant to dock to the station and exit the suit without needing to bring the dirty suit in to the station interior. Something like a Russian Orlan suit with its rear hatch but where it engages with an airlock into the station interior.
Oceanic seawater has no iridium, beryllium, gallium, and indium of note. How many decades are we away from seawater filtering. Is it really that much more profitable, with all the additional R&D, massive infrastructure, etc to accumulate enough precious metals of note?
Keep in mind there are hundreds of thousands of rogue asteroids which are much closer to earth, which can be mined.
Why not use electrostaic charge or some kind of acid wash to remove regolith
The lack of interest in space exploration is one of the main reasons I despise capitalism and would prefer a centrally planned economy.
Asteroids also have lots of phosphates which could be used to grow plants there. This would allow for the creation of a semipermanent asteroid base limited by gravity.
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kvs- Posts : 15857
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Regarding the claim about easy peasy lemon squeezy space mining post above:
E=1/2 mv^2 is a universal formula outside of the relativistic limit (it then becomes the leading order expansion term).
So mountain size rocks in space take the same energy to move anywhere. The only gain from moving orbiting rocks
is from the gravitational potential well where you let the planet do the work for you. But moving huge objects from
the asteroid belt to the Earth is not that cheap. The gain from the Sun's potential well does not offset the need
for a lot of kinetic energy to slow down the belt objects to orbits close to that of Earth with the subsequent capture
by Earth's gravitational potential well.
None of the sci-fi fantasy has these mountains dumped to the Earth from orbit. They always show mining transport
spaceships (and the xenomorphs that infest them).
E=1/2 mv^2 is a universal formula outside of the relativistic limit (it then becomes the leading order expansion term).
So mountain size rocks in space take the same energy to move anywhere. The only gain from moving orbiting rocks
is from the gravitational potential well where you let the planet do the work for you. But moving huge objects from
the asteroid belt to the Earth is not that cheap. The gain from the Sun's potential well does not offset the need
for a lot of kinetic energy to slow down the belt objects to orbits close to that of Earth with the subsequent capture
by Earth's gravitational potential well.
None of the sci-fi fantasy has these mountains dumped to the Earth from orbit. They always show mining transport
spaceships (and the xenomorphs that infest them).
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Singular_Transform- Posts : 1032
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- Post n°686
Re: Russian Space Program: News & Discussion #3
Singular_Transform Tue Feb 09, 2021 12:53 am
kvs wrote:Regarding the claim about easy peasy lemon squeezy space mining post above:
E=1/2 mv^2 is a universal formula outside of the relativistic limit (it then becomes the leading order expansion term).
So mountain size rocks in space take the same energy to move anywhere. The only gain from moving orbiting rocks
is from the gravitational potential well where you let the planet do the work for you. But moving huge objects from
the asteroid belt to the Earth is not that cheap. The gain from the Sun's potential well does not offset the need
for a lot of kinetic energy to slow down the belt objects to orbits close to that of Earth with the subsequent capture
by Earth's gravitational potential well.
None of the sci-fi fantasy has these mountains dumped to the Earth from orbit. They always show mining transport
spaceships (and the xenomorphs that infest them).
Naive and incorrect description of the working of Solar system, and the transport oportunities between the key points.
Example the Voyager was launched with way less energy to leave the solar system, but now going faster than any other successivespacecraft with better engines managed it.
It is due to the gravity asist of the other planetary bodies.
Check the above image, it showing how the asteroids going in-out of te Jupiter trojan points.
With little delta V it is possible to bring even comets back from beyond the Pluto to the Earth-Moon trojain point, with enought slingshot manouvre.
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GarryB- Posts : 40537
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There are 3600 known asteroid closer than the surface of Moon.
A precise list of their chemical composition would be of more value.
Right now you probably get more money by weight for a meteorite than for any precious material you are likely to find in most space rocks.
You make it sound like a lucky dip where every rock has some special prize.
Oceanic seawater has no iridium, beryllium, gallium, and indium of note. How many decades are we away from seawater filtering. Is it really that much more profitable, with all the additional R&D, massive infrastructure, etc to accumulate enough precious metals of note?
Some method of processing enormous amounts of raw material that leads to the collection and storage of useful materials would be a valuable system/process... in fact forget sea water... I would say processing the material at your average city dump area could result in the recovery of a lot of useful material that is other wise going to waste.... literally.
Why not use electrostaic charge or some kind of acid wash to remove regolith
In the vacuum of space?
The lack of interest in space exploration is one of the main reasons I despise capitalism and would prefer a centrally planned economy.
I agree... if we had to rely on everything to be profitable a lot of things would not happen...
A lot of important science is not being done, while lots of useless and pointless science is... not to mention useless duplication of effort and energy.
Don't get me wrong... I think the future of humanity depends on space... what we learn trying to survive on the Moon or Mars without the abundance of resources and materials of Earth will I believe to reuse and energy efficiency techniques and technologies that could be applied here on Earth to massively reduce our impact.
We could start by dramatically reducing reproduction and the number of humans currently here... not by violence or draconian measures... but these children upset at their stolen childhood need to remember that their future personal urge to reproduce and have children is what is really going to kill this planet and all those animal species that are getting wiped out because human settlements are expanding and eliminating their natural habitat.
Animals don't respect fences or lines on a map so when you build houses and farms in their territory then your sheep are their fair game... then of course the farmer kills those animals to protect his livelyhood and then teenagers everywhere wonder where all the Tigers and Lions have gone... while chewing on cheese burgers with cheese from cows milk and meat patties made from horse.
None of the sci-fi fantasy has these mountains dumped to the Earth from orbit. They always show mining transport
spaceships (and the xenomorphs that infest them).
And need we mention space vampires to talk about potential new life forms you might upset on interstellar rocks and material...
You can pretend that a tiny flick of Jupiters gravity is constantly flinging things into and out of the solar system with all sorts of variable results... but you also have to acknowledge that Jupiters gravity is enormous and not something we can hope to mimic... or harness... I am sure a movie where enormous asteroids are launched at a Jupiter swing by transit that takes them on a close skim of the planet surface before escaping the other side on a new trajectory headed towards earth... the close passage near Jupiter shredding the asteroid into fragments that will be much easier to process on the trip to earth orbit... but as I said before... the energy needed to take an object out of a stable orbit is very similar to the level of energy needed to smash it into tiny fragments.
Nomad5891- Posts : 62
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kvs wrote:Regarding the claim about easy peasy lemon squeezy space mining post above:
E=1/2 mv^2 is a universal formula outside of the relativistic limit (it then becomes the leading order expansion term).
So mountain size rocks in space take the same energy to move anywhere. The only gain from moving orbiting rocks
is from the gravitational potential well where you let the planet do the work for you. But moving huge objects from
the asteroid belt to the Earth is not that cheap. The gain from the Sun's potential well does not offset the need
for a lot of kinetic energy to slow down the belt objects to orbits close to that of Earth with the subsequent capture
by Earth's gravitational potential well.
None of the sci-fi fantasy has these mountains dumped to the Earth from orbit. They always show mining transport
spaceships (and the xenomorphs that infest them).
But why would you want to move asteroids to Earth's orbit?
It is not like we would be sending actual miners in space suits with space picks to hammer the rock so they need to have the asteroid close by...
Mining, refering to extracting needed materials from asteroids can be done without need to change its trajectory...bots can mine it autonomously while it moves on its trajectory.
Here on Earth we are not like moving mountains of ore either- we just build a processing plant nearby.
Then you just transport the refined materials where they are needed. And you dont need to transport them at once- it can be done little by little but at higher rate.
kvs- Posts : 15857
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Nomad5891 wrote:kvs wrote:Regarding the claim about easy peasy lemon squeezy space mining post above:
E=1/2 mv^2 is a universal formula outside of the relativistic limit (it then becomes the leading order expansion term).
So mountain size rocks in space take the same energy to move anywhere. The only gain from moving orbiting rocks
is from the gravitational potential well where you let the planet do the work for you. But moving huge objects from
the asteroid belt to the Earth is not that cheap. The gain from the Sun's potential well does not offset the need
for a lot of kinetic energy to slow down the belt objects to orbits close to that of Earth with the subsequent capture
by Earth's gravitational potential well.
None of the sci-fi fantasy has these mountains dumped to the Earth from orbit. They always show mining transport
spaceships (and the xenomorphs that infest them).
But why would you want to move asteroids to Earth's orbit?
It is not like we would be sending actual miners in space suits with space picks to hammer the rock so they need to have the asteroid close by...
Mining, refering to extracting needed materials from asteroids can be done without need to change its trajectory...bots can mine it autonomously while it moves on its trajectory.
Here on Earth we are not like moving mountains of ore either- we just build a processing plant nearby.
Then you just transport the refined materials where they are needed. And you dont need to transport them at once- it can be done little by little but at higher rate.
Read the rest of the thread. Ever hear of the concept of a thread?
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flamming_python- Posts : 9541
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- Post n°690
Re: Russian Space Program: News & Discussion #3
flamming_python Tue Feb 09, 2021 11:11 am
Bringing asteroids down to Earth for mining would be insane
These are things that weigh hundreds of millions of tons. We can barely land 1-2 ton re-entry vehicles and those are far more aerodynamic and controllable
It should be possible to smash them into the moon. When we have mining facilities on the moon and space elevators to it from Earth, that might make sense. Of course though the Moon has already accumulated millions of asteroid impacts. Likely, you'd be able to find a lot of interesting stuff there already.
But other than that, you'd want to mine them in space, and ideally build things right there in space too. I guess smashing processed mineral or metal slabs into the Earth is an option but for all that effort, why not just mine that same thing from the Earth's crust? Within the next few decades mining from the seafloor or ocean floors should be viable, and there are many deposits there, and the cost of land-based mines that go deeper into the Earth's crust should decrease too.
These are things that weigh hundreds of millions of tons. We can barely land 1-2 ton re-entry vehicles and those are far more aerodynamic and controllable
It should be possible to smash them into the moon. When we have mining facilities on the moon and space elevators to it from Earth, that might make sense. Of course though the Moon has already accumulated millions of asteroid impacts. Likely, you'd be able to find a lot of interesting stuff there already.
But other than that, you'd want to mine them in space, and ideally build things right there in space too. I guess smashing processed mineral or metal slabs into the Earth is an option but for all that effort, why not just mine that same thing from the Earth's crust? Within the next few decades mining from the seafloor or ocean floors should be viable, and there are many deposits there, and the cost of land-based mines that go deeper into the Earth's crust should decrease too.
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- Post n°691
Re: Russian Space Program: News & Discussion #3
The-thing-next-door Tue Feb 09, 2021 1:41 pm
flamming_python wrote:Bringing asteroids down to Earth for mining would be insane
These are things that weigh hundreds of millions of tons. We can barely land 1-2 ton re-entry vehicles and those are far more aerodynamic and controllable
I always had the idea that they could just be broken up in orbit with explosive charges and then sent crashing down to a remote/irrelevant wasteland like pindostan or australia.
It should be possible to smash them into the moon. When we have mining facilities on the moon and space elevators to it from Earth, that might make sense.
The space elevator is a retarded science fantasy concept that will never see the light of day.
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Those magic carbon nanotubes will make space elevators a reality any day now. I just know it my heart. /sarc.
I always find it funny how space elevator fantasy completely forgets about the atmosphere. Even if the air density
falls off exponentially with height (e-folding rate of about 7 km), it will still impart a lot of force on this fixed obstacle.
In fact, the integrated exposure to air flow forces of any space elevator is huge compared to any structure built
by humans. Skyscrapers (e.g. Burj Khalifa) and other supertall structures (CN Tower) are designed to bend like
reeds to wind action. So any space elevator will have to be designed to deform in different directions at different
heights (the atmosphere does not flow in the same direction through its whole column at any given position on
the surface, winds reverse direction for various reasons).
Just imagine the resonance failure potential of such a structure. Its very length will be a critical weakness since
it can develop all sorts of bending harmonics and 3D ones at that. The Tacoma Narrows bridge was brought
down by experiencing a resonance with Kelvin-Helmoltz instability rolls hitting it at the right frequency. With
a space elevator even think layers of the atmosphere will exert enormous torques on it when integrated over
kilometers of length.
Gravity is not the only thing to consider for a space elevator. Even if magic can happen and it can be designed to
stay up without tearing itself apart and resonating to hell, the amount of wobble it will need to have is going
to make all elevator rides vomit joy rides.
I always find it funny how space elevator fantasy completely forgets about the atmosphere. Even if the air density
falls off exponentially with height (e-folding rate of about 7 km), it will still impart a lot of force on this fixed obstacle.
In fact, the integrated exposure to air flow forces of any space elevator is huge compared to any structure built
by humans. Skyscrapers (e.g. Burj Khalifa) and other supertall structures (CN Tower) are designed to bend like
reeds to wind action. So any space elevator will have to be designed to deform in different directions at different
heights (the atmosphere does not flow in the same direction through its whole column at any given position on
the surface, winds reverse direction for various reasons).
Just imagine the resonance failure potential of such a structure. Its very length will be a critical weakness since
it can develop all sorts of bending harmonics and 3D ones at that. The Tacoma Narrows bridge was brought
down by experiencing a resonance with Kelvin-Helmoltz instability rolls hitting it at the right frequency. With
a space elevator even think layers of the atmosphere will exert enormous torques on it when integrated over
kilometers of length.
Gravity is not the only thing to consider for a space elevator. Even if magic can happen and it can be designed to
stay up without tearing itself apart and resonating to hell, the amount of wobble it will need to have is going
to make all elevator rides vomit joy rides.
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Singular_Transform- Posts : 1032
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- Post n°693
Re: Russian Space Program: News & Discussion #3
Singular_Transform Tue Feb 09, 2021 6:27 pm
kvs wrote:
Gravity is not the only thing to consider for a space elevator. Even if magic can happen and it can be designed to
stay up without tearing itself apart and resonating to hell, the amount of wobble it will need to have is going
to make all elevator rides vomit joy rides.
Space elevator doesn't need to touch the ground , the end of it can float at any height.
But the required material and mass extreme, not possible to make it without billions of humans living in the space.
And the elevator is an extreme, simple rotation tethers with ion propulsion could decrease dramatically the LEO delta V requirements..
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flamming_python wrote:Bringing asteroids down to Earth for mining would be insane
These are things that weigh hundreds of millions of tons. We can barely land 1-2 ton re-entry vehicles and those are far more aerodynamic and controllable
It should be possible to smash them into the moon. When we have mining facilities on the moon and space elevators to it from Earth, that might make sense. Of course though the Moon has already accumulated millions of asteroid impacts. Likely, you'd be able to find a lot of interesting stuff there already.
But other than that, you'd want to mine them in space, and ideally build things right there in space too. I guess smashing processed mineral or metal slabs into the Earth is an option but for all that effort, why not just mine that same thing from the Earth's crust? Within the next few decades mining from the seafloor or ocean floors should be viable, and there are many deposits there, and the cost of land-based mines that go deeper into the Earth's crust should decrease too.
The problem with "smashing" anything into the earth is that you are essentially bombarding the planet with meteorites... big ones... and these things go BOOOMMMM!!!!!! they hit the ground and release energy equivalent of thermonuclear bombs. The asteroidal body is usually shattered in the impact, and even a solid iron-nickel body will be disrupted. You won't find a nice big easily-mined chunk of pure metal sitting in a shallow hole with a welcome mat laid out saying "please mine me and make a fortune"...
Even if we could divert asteroids from the orbits out past Mars, they will pick up speed (and energy) as they fall into the suns gravity well. It always easier to escape a gravity well and visit outer planets than it is to head towards the Sun. Probes like NASAs Messenger to Mercury had to fly a long complex path involving multiple fly-bys to shed the gravitational energy gained, but it is a small vehicle with abundant deltaV that can follow such a complex well-planned trajectory, not a massive space rock with huge momentum but zero effective propulsion. Rocks will pickup speed and be unable to be captured into Earth orbit on account of their speed being too high. Impact or "litho-braking as it is jokingly called
) would be the only option but as mentioned above, thats not really a workable option...In any case, its not like iron or nickel isn't abundant and cheap on Earth. The idea is so busted, regardless of the hopes and dreams of Star Trek fans.
We are way
How about we shift this conversation to "talking bollocks"?GarryB and kvs like this post
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kvs wrote:Those magic carbon nanotubes will make space elevators a reality any day now. I just know it my heart. /sarc.
I always find it funny how space elevator fantasy completely forgets about the atmosphere. Even if the air density
falls off exponentially with height (e-folding rate of about 7 km), it will still impart a lot of force on this fixed obstacle.
In fact, the integrated exposure to air flow forces of any space elevator is huge compared to any structure built
by humans. Skyscrapers (e.g. Burj Khalifa) and other supertall structures (CN Tower) are designed to bend like
reeds to wind action. So any space elevator will have to be designed to deform in different directions at different
heights (the atmosphere does not flow in the same direction through its whole column at any given position on
the surface, winds reverse direction for various reasons).
Just imagine the resonance failure potential of such a structure. Its very length will be a critical weakness since
it can develop all sorts of bending harmonics and 3D ones at that. The Tacoma Narrows bridge was brought
down by experiencing a resonance with Kelvin-Helmoltz instability rolls hitting it at the right frequency. With
a space elevator even think layers of the atmosphere will exert enormous torques on it when integrated over
kilometers of length.
Gravity is not the only thing to consider for a space elevator. Even if magic can happen and it can be designed to
stay up without tearing itself apart and resonating to hell, the amount of wobble it will need to have is going
to make all elevator rides vomit joy rides.
this. always thought space elevator was a goofy idea. the strain on the tether would be ridiculous. the more you start to see the amount and kind of theoretical materials required it boggles the mind. just pretending it existed tho I wonder what kind of impact a tether like that would have on the environment around it. would it develop a massive charge? how would it effect weather?
I think the best option would be mass drivers or launch loops. they could be made fairly small (relatively speaking) for launching non human, sturdier cargo. I think the key to large scale space travel in the solar system is going to be getting enough critical infrastructure either in various orbits or on the lunar surface and get it to a point where it becomes self sustaining.
the moon should be focused on first. if we could develop self sustaining structures there, man we would be on our way to actual colonization of the solar system. because the moon's gravity is so minimal, mass drivers and rockets there would require so much less energy to attain escape velocities. just imagine if America, Russia, and China together set aside a fourth of their military budget for space exploration/colonization! we could get to that point in our lifetimes.
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Electromagnetic ramps I think deserve more attention than space elevators. They could give rocket planes a substantial boost even
with all the lower atmosphere drag. They cannot be built too high, but can be stretched out horizontally. Imagine accelerating
for 10 km on a curved ramp that concentrates the curvature near the end. Of course there will be energy lost to drag and any
ship that uses such a ramp will have to have ceramic tiles or panels. But actual calculations need to be done and I have not
seen any (maybe I have not looked hard enough).
As for the environmental impact of a space elevator. It will be a giant short circuit in the global electric current. Going through
the ionosphere will create an opportunity for the electrical ground (electron pool) to connect to the positive charges created
on an ongoing basis by hard UV and solar wind associated proton and electron fluxes. Every CME event will produce wonders
of surging electricity from the ground to counter the solar proton precipitation which is not as confined to the auroral belt
and penetrates deeper into the atmosphere.
The global electric circuit is not well studied and its effect on health is ignored. People attribute weather impacts on people's
well being (a real and documented thing) to pressure variations. But some of the effect may be due to changes in the ambient
low level current flow.
Also, if wind mills mess up birds due to infrasound, the space elevator will be producing enormous infrasound emissions with
wavelengths long enough to pollute thousands of kilometers away.
The space elevator idea should be compared to the Tower of Babel.
with all the lower atmosphere drag. They cannot be built too high, but can be stretched out horizontally. Imagine accelerating
for 10 km on a curved ramp that concentrates the curvature near the end. Of course there will be energy lost to drag and any
ship that uses such a ramp will have to have ceramic tiles or panels. But actual calculations need to be done and I have not
seen any (maybe I have not looked hard enough).
As for the environmental impact of a space elevator. It will be a giant short circuit in the global electric current. Going through
the ionosphere will create an opportunity for the electrical ground (electron pool) to connect to the positive charges created
on an ongoing basis by hard UV and solar wind associated proton and electron fluxes. Every CME event will produce wonders
of surging electricity from the ground to counter the solar proton precipitation which is not as confined to the auroral belt
and penetrates deeper into the atmosphere.
The global electric circuit is not well studied and its effect on health is ignored. People attribute weather impacts on people's
well being (a real and documented thing) to pressure variations. But some of the effect may be due to changes in the ambient
low level current flow.
Also, if wind mills mess up birds due to infrasound, the space elevator will be producing enormous infrasound emissions with
wavelengths long enough to pollute thousands of kilometers away.
The space elevator idea should be compared to the Tower of Babel.
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kvs wrote:Electromagnetic ramps I think deserve more attention than space elevators. They could give rocket planes a substantial boost even
with all the lower atmosphere drag. They cannot be built too high, but can be stretched out horizontally. Imagine accelerating
for 10 km on a curved ramp that concentrates the curvature near the end. Of course there will be energy lost to drag and any
ship that uses such a ramp will have to have ceramic tiles or panels. But actual calculations need to be done and I have not
seen any (maybe I have not looked hard enough).
As for the environmental impact of a space elevator. It will be a giant short circuit in the global electric current. Going through
the ionosphere will create an opportunity for the electrical ground (electron pool) to connect to the positive charges created
on an ongoing basis by hard UV and solar wind associated proton and electron fluxes. Every CME event will produce wonders
of surging electricity from the ground to counter the solar proton precipitation which is not as confined to the auroral belt
and penetrates deeper into the atmosphere.
The global electric circuit is not well studied and its effect on health is ignored. People attribute weather impacts on people's
well being (a real and documented thing) to pressure variations. But some of the effect may be due to changes in the ambient
low level current flow.
Also, if wind mills mess up birds due to infrasound, the space elevator will be producing enormous infrasound emissions with
wavelengths long enough to pollute thousands of kilometers away.
The space elevator idea should be compared to the Tower of Babel.
interesting what you are sayin with effects of a massive tether spanning the many atmospheric layers. also you are more right than you may know concerning your last statement. humanity is at a stage where it could annihilate itself with monstrous creations. for Christians these would be called "signs of the times". prophesy speaks of "the king of the west". the demagogue of a European federation. he is called antichrist. essentially nimrod was a foreshadowing of the son of perdition.
we live in strange times.
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kvs wrote:Electromagnetic ramps I think deserve more attention than space elevators. They could give rocket planes a substantial boost even
with all the lower atmosphere drag. They cannot be built too high, but can be stretched out horizontally. Imagine accelerating
for 10 km on a curved ramp that concentrates the curvature near the end. Of course there will be energy lost to drag and any
ship that uses such a ramp will have to have ceramic tiles or panels. But actual calculations need to be done and I have not
seen any (maybe I have not looked hard enough).
As for the environmental impact of a space elevator. It will be a giant short circuit in the global electric current. Going through
the ionosphere will create an opportunity for the electrical ground (electron pool) to connect to the positive charges created
on an ongoing basis by hard UV and solar wind associated proton and electron fluxes. Every CME event will produce wonders
of surging electricity from the ground to counter the solar proton precipitation which is not as confined to the auroral belt
and penetrates deeper into the atmosphere.
The global electric circuit is not well studied and its effect on health is ignored. People attribute weather impacts on people's
well being (a real and documented thing) to pressure variations. But some of the effect may be due to changes in the ambient
low level current flow.
Also, if wind mills mess up birds due to infrasound, the space elevator will be producing enormous infrasound emissions with
wavelengths long enough to pollute thousands of kilometers away.
The space elevator idea should be compared to the Tower of Babel.
EM Catapults also have their share of problems. Since the spacecraft is unpowered and would depend on the ramp for imparting energy, the ship will have to attain the projectile escape velocity, which for earth is around 40,000 km/hr. This will mean two things:
1. With a given practical stretch of ramp it should have a very high acceleration, which, after some threshold value will mean unsuitable for crewed missions.
2. It has a limit to the acceleration attainable and hence to reach escape velocity it will need a longer ramp which could be impractical.
I am too lazy to do the calculations but I guess the solutions will involve staggering quantities for EM ramps as well.
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Daniel_Admassu wrote:kvs wrote:Electromagnetic ramps I think deserve more attention than space elevators. They could give rocket planes a substantial boost even
with all the lower atmosphere drag. They cannot be built too high, but can be stretched out horizontally. Imagine accelerating
for 10 km on a curved ramp that concentrates the curvature near the end. Of course there will be energy lost to drag and any
ship that uses such a ramp will have to have ceramic tiles or panels. But actual calculations need to be done and I have not
seen any (maybe I have not looked hard enough).
As for the environmental impact of a space elevator. It will be a giant short circuit in the global electric current. Going through
the ionosphere will create an opportunity for the electrical ground (electron pool) to connect to the positive charges created
on an ongoing basis by hard UV and solar wind associated proton and electron fluxes. Every CME event will produce wonders
of surging electricity from the ground to counter the solar proton precipitation which is not as confined to the auroral belt
and penetrates deeper into the atmosphere.
The global electric circuit is not well studied and its effect on health is ignored. People attribute weather impacts on people's
well being (a real and documented thing) to pressure variations. But some of the effect may be due to changes in the ambient
low level current flow.
Also, if wind mills mess up birds due to infrasound, the space elevator will be producing enormous infrasound emissions with
wavelengths long enough to pollute thousands of kilometers away.
The space elevator idea should be compared to the Tower of Babel.
EM Catapults also have their share of problems. Since the spacecraft is unpowered and would depend on the ramp for imparting energy, the ship will have to attain the projectile escape velocity, which for earth is around 40,000 km/hr. This will mean two things:
1. With a given practical stretch of ramp it should have a very high acceleration, which, after some threshold value will mean unsuitable for crewed missions.
2. It has a limit to the acceleration attainable and hence to reach escape velocity it will need a longer ramp which could be impractical.
I am too lazy to do the calculations but I guess the solutions will involve staggering quantities for EM ramps as well.
I should have been more explicit. I did not mean full ejection into orbit. I meant reducing the first stage fuel burden. So any
space plane would still need enough fuel to accelerate to LEO speeds. I am not certain whether the first stage fuel that current
gets rockets to 60 km can be fully offset by such a ramp or only partially. I doubt that the second stage fuel requirement can
be eliminated.
If we do not care to transport humans and only cargo, then a rail gun for ballistic injection into orbit of a relatively small payload
may be feasible.
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kvs wrote:
I should have been more explicit. I did not mean full ejection into orbit. I meant reducing the first stage fuel burden. So any
space plane would still need enough fuel to accelerate to LEO speeds. I am not certain whether the first stage fuel that current
gets rockets to 60 km can be fully offset by such a ramp or only partially. I doubt that the second stage fuel requirement can
be eliminated.
If we do not care to transport humans and only cargo, then a rail gun for ballistic injection into orbit of a relatively small payload
may be feasible.
Partial ballistic catapults may be workable as you said. The reason is during the first stages of propulsion most of the fuel expenditure is for lifting the fuel itself. If for instance the first stage of a rocket is meant to last say 6 minutes, then the whole assembly is at its heaviest during those six minutes, most of the weight being the first stage boosters plus their fuel which gets progressively diminished. Thus most of the fuel in the first stage is used to lift the first stage itself. It is the unavoidable waste of non-aerodynamic rocket propulsion. Staging in general is a way to minimize this waste. I rekon replacing even the first small fraction of the first stage propulsion with catapulting should pay huge dividends.
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