It's gonna suck if that "tiny hole" is through the entire rack of control systems, or through the side of your head as the pilot or passenger. But it would explain much.
- Status
A grain of sand or a CO² snowflake or just a fuzzy hydrogen cloud at high velocity (>100km/sec) would instantly become a plasma on impact. Even if the entry hole was quite small, the result inside the hull would be devastating, with incandescent hull fragments flying all over the place. Something akin to an anti-armor shaped-charge. Any exit hole would be many times larger than the entry.
Piezo materials cannot absorb that much energy. Even if they could, the instantaneaous generation of such a huge electrical current would fry every bit of electronics on board, not to speak of Ohm's law melting the materials.
The more I examine this problem, the less I come with an idea. Inertia is so basic it can't be countered.
Piezo materials cannot absorb that much energy. Even if they could, the instantaneaous generation of such a huge electrical current would fry every bit of electronics on board, not to speak of Ohm's law melting the materials.
The more I examine this problem, the less I come with an idea. Inertia is so basic it can't be countered.
The Voyager 1 is currently traveling at about 17 km/s relative to Earth. Although its velocity hasn't always been this high, it's been traveling through the solar system for over thirty years without a significant impact incident as far as I know.
Even though this craft is relatively small (~700 kg), it demonstrates that we can achieve velocities on the order of 20 km/s with the technology of the 1970's. The development of solar sail concepts and ion drives will no doubt push achievable speeds significantly higher if a mission is planned for that purpose.
Granted, space travel cannot be fast relative to the speed of light. I'm wondering how fast it can be using current technology or technology expected to be deployable in the next 20-40 years. In this I would include the possibility of a nuclear fission reactor power source as some have proposed for powereing ion thrusters at great distances from the sun. As I understand it NASA was developing a "SAFE-400" nuclear fission reactor for nuclear-electric propulsion (ion propulsion) in 2001. This small reactor (about 1200 kg) would have developed 400 kw of thermal energy which would provide a net 100 kw of electrical energy.
I need to stress here that I'm thinking in terms of solar system vehicles rather than interstellar vehicles.
Chris
Even though this craft is relatively small (~700 kg), it demonstrates that we can achieve velocities on the order of 20 km/s with the technology of the 1970's. The development of solar sail concepts and ion drives will no doubt push achievable speeds significantly higher if a mission is planned for that purpose.
Granted, space travel cannot be fast relative to the speed of light. I'm wondering how fast it can be using current technology or technology expected to be deployable in the next 20-40 years. In this I would include the possibility of a nuclear fission reactor power source as some have proposed for powereing ion thrusters at great distances from the sun. As I understand it NASA was developing a "SAFE-400" nuclear fission reactor for nuclear-electric propulsion (ion propulsion) in 2001. This small reactor (about 1200 kg) would have developed 400 kw of thermal energy which would provide a net 100 kw of electrical energy.
I need to stress here that I'm thinking in terms of solar system vehicles rather than interstellar vehicles.
Chris
I have not ignored this thread & I have been reading this with quite some interest.
Assuming a craft travelling at let's say 0.99c, that's what, nearly 23.5 x the Earth's own diameter every second or 2 times Jupiter's diameter every second.
Assuming dead ahead a rogue interseller asteroid, ejected from it's own solar system several GYA, say the size of 951 Gaspra, approx 12 KM wide. Impact is fast approaching. It is intersteller space, so the only light is from the stars, surface temperature of the rogue asteroid is what, minus 269 C / 4 K.
Nub of what I am saying, what sort of technology would be required:
1). To detect the cryonically cold asteroid with IR or microwave detectors in time??
2). In order to avoid the disastrous collision, how much energy would be required for lets say a craft the mass of the Space Shuttle, or of lets say an unmanned craft like Voyager or New Horizons or a giant city sized colonization ship with thousands of personnel?
3). At let's say 0.99c would normal remote sensing equipment be able to detect a rogue intersteller asteroid like 951 Gaspra in sufficient time, or would it not work at all due to the extreme blue shift of the rapid approach?
My point is that, of course I have no real information to back this up as yet, is that I think the Milky Way alone has more rogue planets, attendent moons & rings, asteroids & comets than there are stars in the entire local group of galaxies combined.
As Orionrider correctly points out, there are also hydrogen clouds, at a temperature of barely a few K, ice particles, could be CO2, but also normal H2O ice, frozen nitrogen, frozen Oxygen, chondritic particles, metallic particles, all of which would destroy a near c travelling ship.
As Chris also points out, the tecnology to be able to achieve damaging speeds is already well within out grasp & have been achieved. Even with current launch vehicles, like Atlas V, Falcon 9, Delta 4 , Ariane 5, etc, with composite materials, more efficient smaller electronic components, etc, payloads can already travel much faster from launch, such as New Horizons, the fastest ever send off speed from Earth of a craft, of 58,536 km/h; 36,373 mph (had to look up the EXACT speed) from an Atlas V. Voyager 1 is a great point, though her small size will be a bonus, but I suspect over geologic time travelling through intersteller space Voyager 1 as well as Voyager 2, Pioneers 10 & 11 & New Horizons will eventually run into something.
Andrew Brown.
Assuming a craft travelling at let's say 0.99c, that's what, nearly 23.5 x the Earth's own diameter every second or 2 times Jupiter's diameter every second.
Assuming dead ahead a rogue interseller asteroid, ejected from it's own solar system several GYA, say the size of 951 Gaspra, approx 12 KM wide. Impact is fast approaching. It is intersteller space, so the only light is from the stars, surface temperature of the rogue asteroid is what, minus 269 C / 4 K.
Nub of what I am saying, what sort of technology would be required:
1). To detect the cryonically cold asteroid with IR or microwave detectors in time??
2). In order to avoid the disastrous collision, how much energy would be required for lets say a craft the mass of the Space Shuttle, or of lets say an unmanned craft like Voyager or New Horizons or a giant city sized colonization ship with thousands of personnel?
3). At let's say 0.99c would normal remote sensing equipment be able to detect a rogue intersteller asteroid like 951 Gaspra in sufficient time, or would it not work at all due to the extreme blue shift of the rapid approach?
My point is that, of course I have no real information to back this up as yet, is that I think the Milky Way alone has more rogue planets, attendent moons & rings, asteroids & comets than there are stars in the entire local group of galaxies combined.
As Orionrider correctly points out, there are also hydrogen clouds, at a temperature of barely a few K, ice particles, could be CO2, but also normal H2O ice, frozen nitrogen, frozen Oxygen, chondritic particles, metallic particles, all of which would destroy a near c travelling ship.
As Chris also points out, the tecnology to be able to achieve damaging speeds is already well within out grasp & have been achieved. Even with current launch vehicles, like Atlas V, Falcon 9, Delta 4 , Ariane 5, etc, with composite materials, more efficient smaller electronic components, etc, payloads can already travel much faster from launch, such as New Horizons, the fastest ever send off speed from Earth of a craft, of 58,536 km/h; 36,373 mph (had to look up the EXACT speed) from an Atlas V. Voyager 1 is a great point, though her small size will be a bonus, but I suspect over geologic time travelling through intersteller space Voyager 1 as well as Voyager 2, Pioneers 10 & 11 & New Horizons will eventually run into something.
Andrew Brown.
Up to now we are 1 step ahead. A tiny hole will activate our ultra high speed sensors(pico seconds).So the question of detection is resolved if no radar detection possible or so. Ions and electrons will be deflected in a 1mm magnetic shield, radius of deflection r=mv/Be , m =m(e) or m(p). Calculate it for a B=1 tesla to get a normalised radius. Almost .5mm for electron at 100000km/s. Locally generated magnetic field will deflect ions. What is left is the magnetic pressure which as I said a material at near 0K being a superconductor with zero resistance should be able to generate electric power to charge our super batteries or be radiated away or sustain magnetic shield. Please think of this type of material . Perhaps we may get 1 more step ahead. Due to generated mag. force of ions our structure will not be damaged by this mechanism and the energy of impact will compress this sort of material. Is it possible to trap all ions in a magnetic field circulating flux lines? Please complement with your bright ideas, anyone.orionrider":3p3xbrct said:A grain of sand or a CO² snowflake or just a fuzzy hydrogen cloud at high velocity (>100km/sec) would instantly become a plasma on impact. Even if the entry hole was quite small, the result inside the hull would be devastating, with incandescent hull fragments flying all over the place. Something akin to an anti-armor shaped-charge. Any exit hole would be many times larger than the entry.
Piezo materials cannot absorb that much energy. Even if they could, the instantaneaous generation of such a huge electrical current would fry every bit of electronics on board, not to speak of Ohm's law melting the materials.
The more I examine this problem, the less I come with an idea. Inertia is so basic it can't be countered.
-----> orionrider":3ee8focf said:A grain of sand or a CO² snowflake or just a fuzzy hydrogen cloud at high velocity (>100km/sec) would instantly become a plasma on impact. Even if the entry hole was quite small, the result inside the hull would be devastating, with incandescent hull fragments flying all over the place. Something akin to an anti-armor shaped-charge. Any exit hole would be many times larger than the entry......The more I examine this problem, the less I come with an idea. Inertia is so basic it can't be countered.
"Spaced armor", invented in WW1 will solve this problem, if sufficiently enhanced. It's goal is to convert the high energy impact into a ball of decelerated plasma spaced away from the main armor, and then the main armor can absorb the blow. The space vehicle equivalent is called a "Whipple Shield". As practiced now on armored main battle tanks, spaced armor can (barely) protect against kinetic energy round penetrators with impact forces of 7E6 joules penetrating force: (modern fin-stabilized sabot round = 1555 m/s , projectile weight = 6 kg). So if anything, today's technology could (barely) protect against a 1 g micrometeorite at 114 km/s.
Assuming a micrometeorite is actually 1 micrometer in diameter (a much, much more likely scenario, mass = 6.7E-19g assuming a density of 4 g/cm3), then spaced armor capable of shielding a 7E6 J strike could protect up to a velocity of about 1E9 m/s (1,000,000 km/sec...much faster than your upper estimate of 114 km/sec).
I assume using multiple spaced parallel plate armor would do much much better than the above example using a single layer of spaced armor.
Example of spaced "slat" armor on a Stryker. Of course it shouldn't be slats, but this was a good picture:
Spaced armor upgrade on a Leopard2 turret. http://www.leopard2upgrade.romanmbt.com/
Whipple shield on Stardust 1. This very lightweight shield will protect spacecraft from collisions with micrometeoroids and orbital debris whose velocities generally range between 3 and 18 kilometres per second. http://en.wikipedia.org/wiki/Whipple_shield
The Stardust probe, which intentionally passed through the densest part of the coma of comet Wilde 2 collected about 1M grains ('strikes'), the largest of which were 10 grains 100 micrometers in diameter. Stardust survived this transit.http://en.wikipedia.org/wiki/Stardust_(spacecraft)
The Stardust Interstellar Dust Collector on the farside of the Stardust 1 probe (by orientation this collector did not collect cometary dust, only interstellar dust) collected only 28 strikes at 10-20 km/s with a total exposure time of 20m2/day, typical grain size = 0.1 micrometer. However chemical analysis of these has so far shown that all analyzed so far are not of interstellar dust origin.
http://zola.wustl.edu/ref/Westphal_midnight2050.pdf
http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1786.pdf
The Stardust Interstellar Dust Collector on the farside of the Stardust 1 probe (by orientation this collector did not collect cometary dust, only interstellar dust) collected only 28 strikes at 10-20 km/s with a total exposure time of 20m2/day, typical grain size = 0.1 micrometer. However chemical analysis of these has so far shown that all analyzed so far are not of interstellar dust origin.
http://zola.wustl.edu/ref/Westphal_midnight2050.pdf
http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1786.pdf
The Helios probe was lanched in the '70s. It is the fastest man-made object at about 70km/sec.
@KhashayarShatti: do you have any ref or link to this marvelous technology? I have never heard of anything like that.
@Silylene: granted, a 1 micrometer rock isn't much of a threat, even at high speed.
I'm completely confident that as long as the spacecraft travels at a speed comparable to 'natural' objects in it's environment (<100km/sec), the probability of being damaged is small. Space is huge and the distances are such that even Voyager had a very, very remote probability of hitting a significant micrometeorite.
However, when speed increases, so does the mileage. Besides, the population of potentially fatal micrometeorites increases with the inverse square of the relative speed. The result is that the probability of hitting something destructive become higher and higher.
I other words: fast and/or long trips are dangerous.
114km/sec is relatively safe for a 10-day trip to Mars or a few month in the solar system, but it amounts to thousands of years in transit to Proxima Centauri, the next-door star...
If we want to go significantly faster, inertia will inevitably stand in our way.
Most people can't stay on their foot when a 40MPH bus swerves suddenly... :|
@KhashayarShatti: do you have any ref or link to this marvelous technology? I have never heard of anything like that.
@Silylene: granted, a 1 micrometer rock isn't much of a threat, even at high speed.
I'm completely confident that as long as the spacecraft travels at a speed comparable to 'natural' objects in it's environment (<100km/sec), the probability of being damaged is small. Space is huge and the distances are such that even Voyager had a very, very remote probability of hitting a significant micrometeorite.
However, when speed increases, so does the mileage. Besides, the population of potentially fatal micrometeorites increases with the inverse square of the relative speed. The result is that the probability of hitting something destructive become higher and higher.
I other words: fast and/or long trips are dangerous.
114km/sec is relatively safe for a 10-day trip to Mars or a few month in the solar system, but it amounts to thousands of years in transit to Proxima Centauri, the next-door star...
If we want to go significantly faster, inertia will inevitably stand in our way.
Thanks Andrew. I believe the biggest challenge is not so much the required energy, but rather the tremendous G-forces induced by any alteration of the course of a fast spacecraft. Not to mention the effect it would have on the space toilet...
Most people can't stay on their foot when a 40MPH bus swerves suddenly... :|
There is a Wikipedia article on the Helios probes (two) here:http://en.wikipedia.org/wiki/Helios_probesorionrider":pvdotpj5 said:
The article includes the following information:
Chris
I am sure that by the time mankind has found a way to travel at high percentages of the speed of light most all of the other problems associated with deep space flight will have been solved including chance encounters with small solid objects. But my guess is that these developments are at least 2 to 3 hundred years away.
^^ What Bwoody said.
Maybe even a thousand or more years away. But, hopefully, only a few hundred.
Alas, none of us will live to see it.
Maybe even a thousand or more years away. But, hopefully, only a few hundred.
Alas, none of us will live to see it.
Near the light speed.
Are there any problems related to the basic physics?
For example, the uncertainty principle.
If the particle speed were increased very very high, particle positon uncertainty would be increased.
So, at very high speed, space craft and astronaut 's molecular structure would be damaged.
:idea:
Are there any problems related to the basic physics?
For example, the uncertainty principle.
If the particle speed were increased very very high, particle positon uncertainty would be increased.
So, at very high speed, space craft and astronaut 's molecular structure would be damaged.
:idea:
orionrider":3tsd85a9 said:The Helios probe was lanched in the '70s. It is the fastest man-made object at about 70km/sec.
@KhashayarShatti: do you have any ref or link to this marvelous technology? I have never heard of anything like that.
@Silylene: granted, a 1 micrometer rock isn't much of a threat, even at high speed.
Apparently by analogy CRT and photocell could be a good example .
consider a 30KV CRT with beam current of 1mA.
(1/2)*m(e)*v^2=eV
v=10^8 m/s (100000km/s)
Deflection of electrons by magnetic or electric field up to 60 degrees.
No. of electrons hitting the persistent phosphor in 1 sec.: Q=I*t=0.001*1=10^-3 coulombs almost 10^16 electron impacts per second on a very sharp point. A bright spot of light.
Now consider photocell. Light produces electric current.
So is it possible to devise a material that upon impact produces light and electricity efficiently?
What happens when heavy ions hit similar materials like phosphore?
Nope. At least not at that kind of energy level and without destroying the target.
Electrons have no mass to speak of (1/1836th of a proton). Besides, they are obviously charged and that makes deflection very easy. Atoms don't react like that.
bdewoody":1r4n854j said:
+1
However, I think this is the 'best case scenario'. I believe there is a possibility that a whole other level of 'exotism' will be required to completely avoid the laws of inertia. Something like quantum teleportation for instance. Make that millenia from now, if progress does not stop. :|
orionrider":10u9ikkr said:
Please refer to cyclotrons. Convert it to plasma and increase magnetic field.
Hehe, you have gotten more pessimistic than I have in my old age. When I was 17-18 watching Star Trek and 2001 a Space Odessy I was sure that by 2010 we would have a colony on the moon and be at least whizzing around the solar system. Maybe we would have even made First Contact. But alas some of the wheels of progress grind more slowly than others, because in 1968 I would never have guessed I'd have my own personal computer, a phone I could take anywhere, all the music I would ever want to hear coming out of something the size of a cigarette pack and all of the other marvels we use daily.orionrider":zhrsyyge said:
Progress has improved a lot of things. Telephones are better, rockets are better, records are better, and computers and cars and so on...
However, people still die when they fall from the 6th floor. A whole bunch of things have changed, but basic physical laws prevent us from leaping to the next level. Except maybe in the field of genetics, there has been no fundamental game-changing discovery in the previous half century.
All those familiar concepts from science fiction like antigravity, FTL, beam-me-up-Scotty, time travel and more are still magic.
Just like Harry Potter.
Progress is like the 100m sprint world record, it gets better all the time, but by increasingly smaller amounts. Nobody will ever run 100m in 2 seconds and nobody will ever cruise at 0.5c. The same laws of physics prevent both from happening.
However, people still die when they fall from the 6th floor. A whole bunch of things have changed, but basic physical laws prevent us from leaping to the next level. Except maybe in the field of genetics, there has been no fundamental game-changing discovery in the previous half century.
All those familiar concepts from science fiction like antigravity, FTL, beam-me-up-Scotty, time travel and more are still magic.
Just like Harry Potter.
Progress is like the 100m sprint world record, it gets better all the time, but by increasingly smaller amounts. Nobody will ever run 100m in 2 seconds and nobody will ever cruise at 0.5c. The same laws of physics prevent both from happening.
Yep, but if you go back 300 yrs, I'm sure people never thought we would be able to communicate with somebody on the other side of the world pretty much instantaneously ever. 50 yrs later the telegraph was invented. Just going back 100 yrs I think people would think it impossible to create a jet, a nuclear device, an artificial heart, television, etc.
One tiny little discovery in physics may lead to things which seem completely impossible today. I understand with the current materials, technology and understanding of physics, engineers can only tweak things so far and there are limits, but new discoveries may give us entirely different technologies.
Just the fact that quantum entanglement exists gives me hope that we will be able to one day find it possible to circumvent the speed of light. And if we ever do, I believe it would the greatest achievement ever and change our civilization more dramatically than anything before it.
Obviously, I'm just dreaming at the moment, but I do think there is much more to how the universe works than we know, and we can't in our wildest dreams even imagine the technologies we'll have at our disposal even 50 years from now. Or we may get wacked by a meteor or destroy ourselves somehow, which would pretty much put a monkey wrench in my optomistic view.
One tiny little discovery in physics may lead to things which seem completely impossible today. I understand with the current materials, technology and understanding of physics, engineers can only tweak things so far and there are limits, but new discoveries may give us entirely different technologies.
Just the fact that quantum entanglement exists gives me hope that we will be able to one day find it possible to circumvent the speed of light. And if we ever do, I believe it would the greatest achievement ever and change our civilization more dramatically than anything before it.
Obviously, I'm just dreaming at the moment, but I do think there is much more to how the universe works than we know, and we can't in our wildest dreams even imagine the technologies we'll have at our disposal even 50 years from now. Or we may get wacked by a meteor or destroy ourselves somehow, which would pretty much put a monkey wrench in my optomistic view.
orionrider":3kya91v8 said:
But, I think that same arguement can be used during most of our history. I think the game changers come in bursts. Look at how long the dark ages lasted.....then the renaissance came. The world ran on Newton's Laws for centuries.... and all of a sudden, Einstein's Theory of Relativity changed everything. I think right now we will continue to see us approach the limits that we see at a decreasing rate as you said, but then BANG, and we break through to the next level of understanding.
trumptor":3icp7asi said:
Quantum entanglement and teleportation work at the speed of light, not faster. It is currently the most serious candidate for fast travel, not instantaneous travel like in popular science fiction. The principles have been known since 1935. The development of the technology required to exploit this effect is not easy, but it could lead to interesting results.
http://en.wikipedia.org/wiki/Quantum_teleportation
Skipped through the thread and haven't read it all, sorry, but on the points made about "slow ships" taking a long time to get there; generation ships are morally and psychologically implausible, if not impossible. You may want to lock yourself in a flying prison for the rest of your life, but do you have the right to lock your children and your childrens' children in there, and how the heck are they going to feel about it, knowing that back on Earth life in all its glory goes on and they're permanently denied it? I couldn't do that to my kids. I couldn't stand the hatred. There's no reason to think they would have any enthusiasm for this miserable life sentence for some future "greater good" of colonising a planet they'll never see. No, I can't see it ever happening.
If we can't build fast ships practically, space expansion is likely to have to wait for immortality. But that shouldn't be a long wait; it may even happen this century. The one thing we do know about the human genome is that it is a mechanical system which can thus be re-engineered to do anything physically achievable, and immortality certainly is on that list. As such, it's inevitable that at some point our descendents will re-engineer themselves to be immortal. There's no use in continuing with the misery of ageing and dying. You also get to solve the problem of who pays for healthcare simultaneously: the answer is "nobody, you don't need it other than emergency repairs". I envy them.
On bdewoody's point regarding disappointing progress in space flight since we were all kids watching Star Trek- well, that's what you get when you nationalise things. Expense rises, efficiency falls, progress stalls. As a result, we're only just now starting practical commercial human spaceflight industry, forty years after it could have happened. Tragic, really. Compare also with the never-ending disaster of the tokamak project.
If we can't build fast ships practically, space expansion is likely to have to wait for immortality. But that shouldn't be a long wait; it may even happen this century. The one thing we do know about the human genome is that it is a mechanical system which can thus be re-engineered to do anything physically achievable, and immortality certainly is on that list. As such, it's inevitable that at some point our descendents will re-engineer themselves to be immortal. There's no use in continuing with the misery of ageing and dying. You also get to solve the problem of who pays for healthcare simultaneously: the answer is "nobody, you don't need it other than emergency repairs". I envy them.
On bdewoody's point regarding disappointing progress in space flight since we were all kids watching Star Trek- well, that's what you get when you nationalise things. Expense rises, efficiency falls, progress stalls. As a result, we're only just now starting practical commercial human spaceflight industry, forty years after it could have happened. Tragic, really. Compare also with the never-ending disaster of the tokamak project.
Even if immortality is announced today, it remains unproven forever. Life extension proof is also a long time in testing. Ie we might assume there are ten humans over age 120 at present. A year from now, the 3 persons 119 will be 120, making 13, except the probability is two of the 13 will die, thus resulting in only 10% progresses, but the sample is too small to have any certainty. Much the same, in 2050, we may have 20 people over age 130, net with the deaths that occur over the 40 years. The sample is perhaps big enough to project at least one person over 140 in 2060, but not for sure.
Unless the treatment can be given to billions of people world wide, the average life expectancy in 2050, will be perhaps 4 years longer, which is approximately an extrapolation of the curve for the past century or more.
Proof is even farther in the future if the treatment can only be applied to persons not born yet, as we need to wait 141 years to see if any of them live to age 140. Neil
Unless the treatment can be given to billions of people world wide, the average life expectancy in 2050, will be perhaps 4 years longer, which is approximately an extrapolation of the curve for the past century or more.
Proof is even farther in the future if the treatment can only be applied to persons not born yet, as we need to wait 141 years to see if any of them live to age 140. Neil
Generation ships, as envisioned, are not like the ISS. They're generally considered to be more like mid-sized cities with populations ranging up to 100,000 people, "downtown" areas, "suburbs", "industrial" areas and "rural" areas.jaxtraw":3twyylag said:
People have children and raise them no matter what their circumstances are or where they find themselves. Whether they're living in New York City, a "holler" in West Virginia, a patch of jungle in the Amazon rain forest, or on a two square mile island in Micronesia, life goes on. Until recently (the last few centuries) most people were born, lived and died in the same place. They didn't know much about the rest of life on Earth "...and all its glory..." and, generally, were content with the home "God" gave them. Of course, we all know that "God" didn't give them their home - a bunch of their ancestors moved there from somewhere else.
Chris
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