Swarming Proxima Centauri: Picospacecraft Swarms over Interstellar Distances(astrobiology.com)
astrobiology.com
Swarming Proxima Centauri: Picospacecraft Swarms over Interstellar Distances
https://astrobiology.com/2024/05/swarming-proxima-centauri-coherent-picospacecraft-swarms-over-interstellar-distances.html
150 コメント
>Obviously there’s nothing on Proxima, just like there’s nothing on the Moon.
Not necessarily obviously. The moons of the gas giants was thought to be inert and boring, until we went there and realized they are varied and brimming with interesting features.
Not necessarily obviously. The moons of the gas giants was thought to be inert and boring, until we went there and realized they are varied and brimming with interesting features.
> they are varied and brimming with interesting features.
one of those features being lifeless
one of those features being lifeless
Right now Enceladus is the most likely target for extant life in the solar system, and is one of four moons with a subsurface water ocean. We know almost nothing about them.
In order to make any of these interstellar dreams at all useful, we’d need to master the ability to explore the full gamut of what a solar system can offer. It’s just not sexy enough to make headlines.
Most proposed interstellar missions (including the article) are just flybys. We won't learn much more about how to do flybys by observing our own solar system.
The data from such a flyby might build the support necessary to develop propulsion technologies that allow us to slow down at interstellar targets. But they'd be decades into the future, by that time we will have done a lot more exploration in our solar system as well
The data from such a flyby might build the support necessary to develop propulsion technologies that allow us to slow down at interstellar targets. But they'd be decades into the future, by that time we will have done a lot more exploration in our solar system as well
For all we know Europa and Enceledous could support millions of tons of biomass.
Life isn't the only interesting thing
Such confidence, such hubris.
Where does it come from?
Where does it come from?
Many humans spend their formative years learning that they can overcome most obstacles with enough effort and willpower.
This optimism carries over to their adult life, despite the newer obstacles being infinitely more difficult and complex so as to be incomparable.
This optimism carries over to their adult life, despite the newer obstacles being infinitely more difficult and complex so as to be incomparable.
That's not relevant to assuming that the rest of the solar system is lifeless; I'm assuming you didn't see what GP was replying to.
Anyway, in general, over-optimism is much better than the opposite, because over-optimism runs into contradictions and gets corrected much more quickly than pessimism does, if it ever does.
Anyway, in general, over-optimism is much better than the opposite, because over-optimism runs into contradictions and gets corrected much more quickly than pessimism does, if it ever does.
The trouble with being at the beginning of space travel is that we will get better and faster at it.
In fact there's a 'law' or 'paradox' that I can't remember the name of - but if we were to launch in 2076 at 0.2c, we could eventually launch something faster, than might even overtake the original probes.
In fact there's a 'law' or 'paradox' that I can't remember the name of - but if we were to launch in 2076 at 0.2c, we could eventually launch something faster, than might even overtake the original probes.
> if we were to launch in 2076 at 0.2c, we could eventually launch something faster
If you never launch at 0.2c, you’re less likely to build the kit that launches something faster later.
If you never launch at 0.2c, you’re less likely to build the kit that launches something faster later.
I think you're thinking of the Lightspeed Leapfrog trope[1].
(In a more general sense, it's the inverse of the first-mover advantage: the law of the handicap of a head start[32])
Or: the early bird gets the worm, but the second mouse gets the cheese.
[1] https://tvtropes.org/pmwiki/pmwiki.php/Main/LightspeedLeapfr...
[2] https://en.wikipedia.org/wiki/Law_of_the_handicap_of_a_head_...
(In a more general sense, it's the inverse of the first-mover advantage: the law of the handicap of a head start[32])
Or: the early bird gets the worm, but the second mouse gets the cheese.
[1] https://tvtropes.org/pmwiki/pmwiki.php/Main/LightspeedLeapfr...
[2] https://en.wikipedia.org/wiki/Law_of_the_handicap_of_a_head_...
> In fact there's a 'law' or 'paradox' that I can't remember the name of
The incessant obsolescence postulate.
The incessant obsolescence postulate.
Obviously there's nothing...
I was stumped by that. You don't know until you look.
I was stumped by that. You don't know until you look.
[deleted]
In 2124 someone will synthesize your consciousness from this and other posts and tell "you" about the results.
Please don't synthesize my consciousness from Hacker News posts.
Or my online presence in totality, to be honest. Who I am online is only a small part of who I am.
Just like being a father, or an employee, or a woodworker do not fully define me as human, being a little snarky bitch on the Internet also does not sometime define me.
Just like being a father, or an employee, or a woodworker do not fully define me as human, being a little snarky bitch on the Internet also does not sometime define me.
On the internet, I'm a wolf. So synthesising a persona from my digital presence would be…
well, 100% on brand for how weird everything else is, honestly.
well, 100% on brand for how weird everything else is, honestly.
By asking that, you just guarantee your synthesized consciousness will be miserable.
Well, at least it will be accurate.
too late, my imagination is fuuuming
[deleted]
It’s going to be Roko’s Basilisk who is angry at me for making fun of cryptocurrency on HN and therefore delaying the Buttcoin Singularity by 3.7 minutes.
As a punishment I’ll have neutron star hot NFTs poked into my virtual eye sockets forever. But in between the tortures, the merciful Basilisk will grant me a glimpse of Proxima Centauri taken by its interstellar drone armada.
As a punishment I’ll have neutron star hot NFTs poked into my virtual eye sockets forever. But in between the tortures, the merciful Basilisk will grant me a glimpse of Proxima Centauri taken by its interstellar drone armada.
My favorite thing about Roko's Basilisk is how a bunch of hard-nosed rationalists using remorseless logic somehow managed to conclude that God is real and will torture you in Hell forever if you sin.
a zip file of his consciousness is still a zip file :)
Invictus0(7)
> A swarm whose members are in known spatial positions relative to each other, having state-of-the-art microminiaturized clocks to keep synchrony, can utilize its entire population to communicate with Earth, periodically building up a single short but extremely bright contemporaneous laser pulse from all of them. Operational coherence means each probe sends the same data but adjusts its emission time according to its relative position, such that all pulses arrive simultaneously at the receiving arrays on Earth. This effectively multiplies the power from any one probe by the number N of probes in the swarm, providing orders of magnitude greater data return.
This sounds unfeasible. They have no way to keep station from what I understand, the interstellar medium is relatively empty but there will still be some drift over the light years. Having all of these independent craft synchronize and overlay their signals precisely enough for it to be receivable on Earth seems implausible. Can you say hella attenuation? I'd like to see some numbers...
This sounds unfeasible. They have no way to keep station from what I understand, the interstellar medium is relatively empty but there will still be some drift over the light years. Having all of these independent craft synchronize and overlay their signals precisely enough for it to be receivable on Earth seems implausible. Can you say hella attenuation? I'd like to see some numbers...
They don't need to keep exact position; they just need to know their relative distance offsets from Earth to synchronize pulses.
They can do some work to keep station; the idea is that by adjusting attitude, they can adjust the magnitude and direction of their drag vector.
https://arxiv.org/abs/2309.07061
It's absolutely infeasible with current technology, but it doesn't look like it's total unobtanium.
They can do some work to keep station; the idea is that by adjusting attitude, they can adjust the magnitude and direction of their drag vector.
https://arxiv.org/abs/2309.07061
It's absolutely infeasible with current technology, but it doesn't look like it's total unobtanium.
[deleted]
I agree. Sounds like the plan is to have the signals from each probe add up coherently, which means the laser pulses need to be coherent with each other. The wavelength of optical light is 100s of nanometers, so that is the level of precision required spatially, relative to the much much larger probe spacing that they quote. This (plus the required temporal coherence) is probably not possible without the probes actively locking their lasers to each other, but now each probe needs the optics to send and detect the optical signal from at least its nearest neighbors. I can't say if this is impossible given the weight restrictions, but it sounds rough.
Can you say relativistic corrections hell? "Over lightyears" means it takes literally years for these things to coordinate moves with each other, to say nothing of post-launch coordination messages from Earth.
> "Over lightyears" means it takes literally years for these things to coordinate moves with each other
The swarm ends up around 100,000km wide. Initial distances are longer, but never on the order of light years.
The swarm ends up around 100,000km wide. Initial distances are longer, but never on the order of light years.
Yeah, I think he missed the part where it discussed the swarm would have to be mostly autonomous since communicating back to earth for any sort of management commands is completely out of the question.
It's amazing they can still do it with voyager which is roughly 24 hours for one way traffic, 48 for round trip.
It's amazing they can still do it with voyager which is roughly 24 hours for one way traffic, 48 for round trip.
I'm not sure "swarm over interstellar distances" makes any sense here, then. How many stars are within 100,000 km of each other and what percentage of stars does that represent?
Ships _spread out_ over 100,000km will literally cover interstellar distances as a swarm by _traveling to another star_. That's the whole point. A bunch of insects can swarm a thousand km from the time it forms to when it breaks up, even if the swarm itself is never more than a couple of km in diameter.
The idea is, you launch a large number of probes, accelerated one by one, working so that they'll arrive at the same time to the same star (Proxima Centauri). If you lose a bunch, no problem.
They'll be spread out over a big distance, but team up to do imaging and to return data from that star.
They'll be spread out over a big distance, but team up to do imaging and to return data from that star.
> They'll be spread out over a big distance
Compared to the distance that you'd go to get a coffee, yes. Compared to the distance to Proxima Centauri, oh hell no. Compared to that distance, they travel as a pack.
There's about a "402 million to 1" ratio between the two distances, 100 000km size of the swarm vs the 40,208,000,000,000 km distance to Proxima Centauri.
https://imagine.gsfc.nasa.gov/features/cosmic/nearest_star_i...
A swarm 100 000km wide could in its entirety pass between the Earth and the Moon with room to spare.
https://www.nasa.gov/wp-content/uploads/2009/07/180561main_E...
Compared to the distance that you'd go to get a coffee, yes. Compared to the distance to Proxima Centauri, oh hell no. Compared to that distance, they travel as a pack.
There's about a "402 million to 1" ratio between the two distances, 100 000km size of the swarm vs the 40,208,000,000,000 km distance to Proxima Centauri.
https://imagine.gsfc.nasa.gov/features/cosmic/nearest_star_i...
A swarm 100 000km wide could in its entirety pass between the Earth and the Moon with room to spare.
https://www.nasa.gov/wp-content/uploads/2009/07/180561main_E...
Yes, of course. We all know these numbers. I teach a space engineering class where students chirp out in recitation "400km to LEO, 40,000 km to GEO, 400,000 km to the moon". The degree of "well acktually" trying to be pedantic here is unnecessary.
If a swarm of bees goes a couple of miles away, they don't spread out over a couple of mile distance. They are a relatively tight pack that then goes to the new place and then converges to be quite small. That's the same as what this mission is.
100,000 km is quite small as far as interstellar distances are concerned, but quite big as far as an aperture for distributed imaging or beamforming (and for avoiding hazards that are hard to see beforehand). The latter, of course, is what actually matters.
If a swarm of bees goes a couple of miles away, they don't spread out over a couple of mile distance. They are a relatively tight pack that then goes to the new place and then converges to be quite small. That's the same as what this mission is.
100,000 km is quite small as far as interstellar distances are concerned, but quite big as far as an aperture for distributed imaging or beamforming (and for avoiding hazards that are hard to see beforehand). The latter, of course, is what actually matters.
My apologies, I was not trying to be pedantic or to correct you. It's for other readers too and does not contradict, really.
FWIW, I looked up those numbers because I do not have them memorised. The typical reader here seems even less informed than that, and they would benefit - I don't think that "we all know these numbers".
FWIW, I looked up those numbers because I do not have them memorised. The typical reader here seems even less informed than that, and they would benefit - I don't think that "we all know these numbers".
Seems like I should be the one apologizing; it's hard to know tone online, and I thought you were trying to assert it wasn't a swarm like the other people. Sorry about that.
(P.S. they're not the right numbers; just the right orders of magnitude).
(P.S. they're not the right numbers; just the right orders of magnitude).
> How many stars are within 100,000 km of each other and what percentage of stars does that represent
That's less than half the distance from the Earth to the Moon, so leaving binary star systems to one side, the answer is none and zero.
A large asteroid passing 100,000 km from the Earth is a considered a near miss in my book, since it's easily cislunar.
But you're missing the point entirely; parent is saying that individual craft in the swarm are within that distance of each other - that's the diameter of the swarm; the line "The swarm ends up around 100,000km wide" gives that away.
The distance between stars is orders of magnitude larger. "the swarm" crosses interstellar distances and communicates back as a whole. But communications between elements of the swarm do not and cannot cross that distance, they have to stay quite close to each other, e.g. within 100,000 km as they cross the void together.
That's less than half the distance from the Earth to the Moon, so leaving binary star systems to one side, the answer is none and zero.
A large asteroid passing 100,000 km from the Earth is a considered a near miss in my book, since it's easily cislunar.
But you're missing the point entirely; parent is saying that individual craft in the swarm are within that distance of each other - that's the diameter of the swarm; the line "The swarm ends up around 100,000km wide" gives that away.
The distance between stars is orders of magnitude larger. "the swarm" crosses interstellar distances and communicates back as a whole. But communications between elements of the swarm do not and cannot cross that distance, they have to stay quite close to each other, e.g. within 100,000 km as they cross the void together.
You're missing the point entirely: framing the swarm as "covering interstellar distances" is misleading and betrays a certain naivete in thinking about space travel that compromises the reporting on this plan.
Bees swarm over distances of miles. But the swarm doesn't stretch out miles. They form a dense group that moves somewhere miles away.
> You're missing the point entirely
I think not.
> "covering interstellar distances" is misleading
It can be read in 2 ways yes (is the interstellar distance crossed by the swarm who do that together, or does the radius of the swarm encompass interstellar distance) but it's clear which one is intended. Again, "The swarm ends up around 100,000km wide" tells you which one it is. Non-naïve people know or look up that 100,000km is not even an interplanetary distance, let alone an interstellar one. It's relatively tightly bunched when crossing the 40,208,000,000,000 km to Proxima Centauri. Yes I look this kind of thing up.
> a certain naivete in thinking about space travel that compromises
Don't be absurd.
I think not.
> "covering interstellar distances" is misleading
It can be read in 2 ways yes (is the interstellar distance crossed by the swarm who do that together, or does the radius of the swarm encompass interstellar distance) but it's clear which one is intended. Again, "The swarm ends up around 100,000km wide" tells you which one it is. Non-naïve people know or look up that 100,000km is not even an interplanetary distance, let alone an interstellar one. It's relatively tightly bunched when crossing the 40,208,000,000,000 km to Proxima Centauri. Yes I look this kind of thing up.
> a certain naivete in thinking about space travel that compromises
Don't be absurd.
Is this the same argument you proffer every time clickbait language is used?
station keeping is definitely possible. each craft could use its comms laser for impulse
On a similar vein, I have a deep yearning for a solar gravity lens to be used to image exo planets within my lifetime. I've got a long time, but it's frustrating to see so little movement on big astronomy projects like these.
What about the Terrascope [1] concept instead? Using the Earth's atmoshpere as a refractive lens. This requires a telescope of L2 rather than some 540AU away for a solar gravity lens.
Not as powerful as the latter, but much more do-able just on the distance scale alone. It would essentially be an "Eath-observing" James Webb
[1] https://ui.adsabs.harvard.edu/abs/2019ESS.....433310K/abstra...
Not as powerful as the latter, but much more do-able just on the distance scale alone. It would essentially be an "Eath-observing" James Webb
[1] https://ui.adsabs.harvard.edu/abs/2019ESS.....433310K/abstra...
You've got a long time—Will you please kindly take personal responsibility to ensure we see images of seasonal foliage changes in vast forests on superearths hundreds of light years away using billions of solar gravity lensing observatories built and launched by self-replicating processes? Also don't be a slacker and get first lens light by 2050?
Same here! One of my dream projects to see happen before I die.
For those that don't know what this is or could mean:
https://www.space.com/sun-gravity-could-help-observe-exoplan...
For those that don't know what this is or could mean:
https://www.space.com/sun-gravity-could-help-observe-exoplan...
so little <public> movement. there is a concept of decadal projects where they are being iterated on in working groups or just smaller groups in general. they may not get much public discussion on purpose. the ideas just might not be viable yet, but then some new tech comes along and an old idea gets pulled back out of the drawer. also, so ideas are so fantastical, they receive immediate negative blow back which makes it impossible for congress critters to get on board and fund them. luckily, the public success of JWST (even after all of the delays) has helped put a positive look on some of these projects. just hope that Boeing is not attached to it
I'll hold faith then :)
All you need to do to see some change is pick a goal and commit a long time towards it. So if you have a long time maybe you can help with this project that you would like to see.
Swarms for this application seem inefficient to me because they duplicate so much of the mass-- mass that could be used not as single basket but as adequate redundancy in a single craft.
Also, this seems impossible:
> An initial string 100s to 1000s of AU long dynamically coalesces itself over time into a lens-shaped mesh network #100,000 km across, sufficient to account for ephemeris errors at Proxima
How does any object as small as what they're proposing at the extreme head or tail of the string whose only energy source is a laser several light years away lower (or increase) its velocity enough to reposition itself several hundred astronomical units to form a lens 100,000 km across and then increase (or decrease) its velocity in order maintain formation?
Is the lens pointed at the target, for imaging, or pointed at earth for communications? If the former how does it achieve the gain needed to send a signal to earth? If the latter how does it perform any useful science with the target?
Has anyone done even a rudimentary SWAG link budget calculation for communications?
Also, laser beams diverge and lose coherence. Why does it seem as though they are assuming that laser beams stay converged and coherent forever?
What is the energy density of a 100GW laser beam that has diverged to 100,000km at a ±50k km radial distance because I assume that the swarm components at the edges of the lens will need power the same as those at the center?
Also, this seems impossible:
> An initial string 100s to 1000s of AU long dynamically coalesces itself over time into a lens-shaped mesh network #100,000 km across, sufficient to account for ephemeris errors at Proxima
How does any object as small as what they're proposing at the extreme head or tail of the string whose only energy source is a laser several light years away lower (or increase) its velocity enough to reposition itself several hundred astronomical units to form a lens 100,000 km across and then increase (or decrease) its velocity in order maintain formation?
Is the lens pointed at the target, for imaging, or pointed at earth for communications? If the former how does it achieve the gain needed to send a signal to earth? If the latter how does it perform any useful science with the target?
Has anyone done even a rudimentary SWAG link budget calculation for communications?
Also, laser beams diverge and lose coherence. Why does it seem as though they are assuming that laser beams stay converged and coherent forever?
What is the energy density of a 100GW laser beam that has diverged to 100,000km at a ±50k km radial distance because I assume that the swarm components at the edges of the lens will need power the same as those at the center?
> Swarms for this application seem inefficient to me because they duplicate so much of the mass-- mass that could be used not as single basket but as adequate redundancy in a single craft.
They're using swarms because we can't accelerate an object that weighs more than a couple grams to relativistic speed with realistic technology. Therefore we have to use a small craft. And since that small craft can't do everything, we send a bunch.
> How does any object as small as what they're proposing at the extreme head or tail of the string whose only energy source is a laser several light years away lower (or increase) its velocity enough to reposition itself several hundred astronomical units to form a lens 100,000 km across and then increase (or decrease) its velocity in order maintain formation?
That's not at all what they're proposing. Each craft would have its own energy source. There is also no string. The "string" and "mesh" here refer to geometry, not to actual real objects.
edit: as to how they come together, that's the previous sentence from your quote:
> Initial boost is modulated so the tail of the string catches up with the head (“time on target”). Exploiting drag imparted by the interstellar medium (“velocity on target”) over the 20-year cruise keeps the group together once assembled.
answering more:
> Is the lens pointed at the target, for imaging, or pointed at earth for communications?
The coms lens has nothing to do with the lens shape of the probe mesh or with the instruments used to collect data. You use two different things for taking images and sending them.
> If the former how does it achieve the gain needed to send a signal to earth?
From the article:
> .. periodically building up a single short but extremely bright contemporaneous laser pulse from all of them. Operational coherence means each probe sends the same data but adjusts its emission time according to its relative position, such that all pulses arrive simultaneously at the receiving arrays on Earth.
> What is the energy density of a 100GW laser beam that has diverged to 100,000km at a ±50k km radial distance because I assume that the swarm components at the edges of the lens will need power the same as those at the center?
Irrelevant since that's not the power source.
They're using swarms because we can't accelerate an object that weighs more than a couple grams to relativistic speed with realistic technology. Therefore we have to use a small craft. And since that small craft can't do everything, we send a bunch.
> How does any object as small as what they're proposing at the extreme head or tail of the string whose only energy source is a laser several light years away lower (or increase) its velocity enough to reposition itself several hundred astronomical units to form a lens 100,000 km across and then increase (or decrease) its velocity in order maintain formation?
That's not at all what they're proposing. Each craft would have its own energy source. There is also no string. The "string" and "mesh" here refer to geometry, not to actual real objects.
edit: as to how they come together, that's the previous sentence from your quote:
> Initial boost is modulated so the tail of the string catches up with the head (“time on target”). Exploiting drag imparted by the interstellar medium (“velocity on target”) over the 20-year cruise keeps the group together once assembled.
answering more:
> Is the lens pointed at the target, for imaging, or pointed at earth for communications?
The coms lens has nothing to do with the lens shape of the probe mesh or with the instruments used to collect data. You use two different things for taking images and sending them.
> If the former how does it achieve the gain needed to send a signal to earth?
From the article:
> .. periodically building up a single short but extremely bright contemporaneous laser pulse from all of them. Operational coherence means each probe sends the same data but adjusts its emission time according to its relative position, such that all pulses arrive simultaneously at the receiving arrays on Earth.
> What is the energy density of a 100GW laser beam that has diverged to 100,000km at a ±50k km radial distance because I assume that the swarm components at the edges of the lens will need power the same as those at the center?
Irrelevant since that's not the power source.
>> Initial boost is modulated so the tail of the string catches up with the head (“time on target”). Exploiting drag imparted by the interstellar medium (“velocity on target”) over the 20-year cruise keeps the group together once assembled.
That is the actual, literal, impossible part. If the head is launched at speed x and the tail at speed y when they catch up they cannot stay assembled, unless "drag" is code for "magic".
>Irrelevant since that's not the power source.
What is the power source for the device, which weighs "GRAMS"? 1 gram is several dozen grains of rice. So what is the power source, expected to last decades, power data acquisition, processing, and transmission, and inter-swarm communications and station-keeping that weighs several dozen grains of rice?
More quantum-quantum-quantum antimatter nonsense?
I was trying to be generous by assuming energy harvesting, and not delving into fantasy.
The lens direction is VERY RELEVANT because the idea of getting signals back to earth is a broad array of devices all signaling simultaneously so the lens would ideally be perpendicular to earth. For example if the lens was pointed at the target it would present a smaller profile to observers on earth (maybe even a thin line) which would be more difficult to detect than a 100k km wide circle. The same rules apply to observations: any synthetic apertures created would be useless unless grossly pointed in the general direction of the target.
That is the actual, literal, impossible part. If the head is launched at speed x and the tail at speed y when they catch up they cannot stay assembled, unless "drag" is code for "magic".
>Irrelevant since that's not the power source.
What is the power source for the device, which weighs "GRAMS"? 1 gram is several dozen grains of rice. So what is the power source, expected to last decades, power data acquisition, processing, and transmission, and inter-swarm communications and station-keeping that weighs several dozen grains of rice?
More quantum-quantum-quantum antimatter nonsense?
I was trying to be generous by assuming energy harvesting, and not delving into fantasy.
The lens direction is VERY RELEVANT because the idea of getting signals back to earth is a broad array of devices all signaling simultaneously so the lens would ideally be perpendicular to earth. For example if the lens was pointed at the target it would present a smaller profile to observers on earth (maybe even a thin line) which would be more difficult to detect than a 100k km wide circle. The same rules apply to observations: any synthetic apertures created would be useless unless grossly pointed in the general direction of the target.
> That is the actual, literal, impossible part. If the head is launched at speed x and the tail at speed y when they catch up they cannot stay assembled, unless "drag" is code for "magic".
Drag is just drag. The craft are all launched at roughly the same speed and will start slowing down due to drag. By changing orientation they can control the speed/direction in which they slow down. This is a small effect, because the drag imparted by gases in interstellar space is minimal, but over 20 years at .2c it seems like it should work.
If there's a problem with this plan it's more likely to be that the encounters with the interstellar medium is more energetic than we expect and the craft either slow down too much or are destroyed by gases constantly impacting at .2c for years. But assuming the craft have enough shielding, the idea of using the drag to maneuver should work fine.
Drag is just drag. The craft are all launched at roughly the same speed and will start slowing down due to drag. By changing orientation they can control the speed/direction in which they slow down. This is a small effect, because the drag imparted by gases in interstellar space is minimal, but over 20 years at .2c it seems like it should work.
If there's a problem with this plan it's more likely to be that the encounters with the interstellar medium is more energetic than we expect and the craft either slow down too much or are destroyed by gases constantly impacting at .2c for years. But assuming the craft have enough shielding, the idea of using the drag to maneuver should work fine.
> By changing orientation they can control the speed/direction in which they slow down.
I apologize for not communicating clearly but that is the impossible part.
It will only work if the interstellar wind is, to borrow nautical terms, "in irons" or "running" (in line with either from ahead or behind the direction of travel) and that is impossible to either know, predict, or assume. From all other directions there are lateral forces that are impossible to overcome.
For example, if you are in a sailboat following another sailboat in calm waters with consistent wind and the lead sailboat slows down or the trailing puts out more sail to speed up to narrow a gap, one of the two will fall out of the line of travel due to lateral forces and will be forced to apply rudder to compensate. These things have no rudders.
The same thing happens to airplanes. If they increase or decrease drag either altitude or speed (or both) changes and control inputs are needed maintain position.
There is no ocean of water or air in space in which to steer.
I suppose if we launch and preposition several hundred billion space weather stations along the route in advance, we will understand the forces involved and be able to set the swarm components off on the trajectory needed so that the drag plan will work.
I apologize for not communicating clearly but that is the impossible part.
It will only work if the interstellar wind is, to borrow nautical terms, "in irons" or "running" (in line with either from ahead or behind the direction of travel) and that is impossible to either know, predict, or assume. From all other directions there are lateral forces that are impossible to overcome.
For example, if you are in a sailboat following another sailboat in calm waters with consistent wind and the lead sailboat slows down or the trailing puts out more sail to speed up to narrow a gap, one of the two will fall out of the line of travel due to lateral forces and will be forced to apply rudder to compensate. These things have no rudders.
The same thing happens to airplanes. If they increase or decrease drag either altitude or speed (or both) changes and control inputs are needed maintain position.
There is no ocean of water or air in space in which to steer.
I suppose if we launch and preposition several hundred billion space weather stations along the route in advance, we will understand the forces involved and be able to set the swarm components off on the trajectory needed so that the drag plan will work.
I think the analogy would be more like craft falling through the atmosphere. I found one NASA article that says interstellar wind speed is 26 km/s, which is four orders of magnitude smaller than .2c. Practically speaking I think you can model it as a constant .2c headwind.
> will be forced to apply rudder to compensate. These things have no rudders.
These things are pretty hypothetical, but I think the concept pretty clearly requires them to have something resembling a rudder since that's their only realistic means of attitude control.
Or, essentially they would be like people in wingsuits falling.
> will be forced to apply rudder to compensate. These things have no rudders.
These things are pretty hypothetical, but I think the concept pretty clearly requires them to have something resembling a rudder since that's their only realistic means of attitude control.
Or, essentially they would be like people in wingsuits falling.
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I don't think you need to worry about winds when travelling at 0.2c...
and there's plenty of stuff in space - nebulas are just when stuff is dense enough to see visually, but hydrogen lines reveal molecules everywhere
and there's plenty of stuff in space - nebulas are just when stuff is dense enough to see visually, but hydrogen lines reveal molecules everywhere
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I'd like to see a stellaser. Asimov wrote about them, but we'd just need to get one close enough to the Sun and have unlimited power to the darker parts of space
Could be a cover project for something classified, such as a ground based laser paired with an orbital mirror on lets say an X-37 or something.
People who host pitch-drop experiments don't do it with an expectation of a definitive outcome inside their lifetime.
PhD students at JPL before rocketry became more routine very probably felt the same.
I think anyone considering a role in this endevour would need to be willing to accept at best, 3rd or 2nd order deliverable outcomes in their working lifetime to take pleasure/kudos in, and not actually discovering outcomes of substance from the devices.
If you compare that to e.g. helping build the SKA, or launch Webb, It is arguable they have more bang-for-buck per individual, outcome-in-lifetime. But, thats not to say they do "better" just that they deliver science to their primary mission faster.
Good science in the secondary and tertiary effect space, behaviour of systems designed for long shelflive in space before activation, novel propulsion models, no end of good science.
I am told If Voyager was done again, it might well be done to deliver outcomes in the same place, sooner because we can now afford launch methods and RF systems which are 10x or 100x better.
But not "here's the latest image from Proxima Centauri up close" outcomes for anyone working on Brilliant dust. The cost to get to interesting fractions of c is just too high.
PhD students at JPL before rocketry became more routine very probably felt the same.
I think anyone considering a role in this endevour would need to be willing to accept at best, 3rd or 2nd order deliverable outcomes in their working lifetime to take pleasure/kudos in, and not actually discovering outcomes of substance from the devices.
If you compare that to e.g. helping build the SKA, or launch Webb, It is arguable they have more bang-for-buck per individual, outcome-in-lifetime. But, thats not to say they do "better" just that they deliver science to their primary mission faster.
Good science in the secondary and tertiary effect space, behaviour of systems designed for long shelflive in space before activation, novel propulsion models, no end of good science.
I am told If Voyager was done again, it might well be done to deliver outcomes in the same place, sooner because we can now afford launch methods and RF systems which are 10x or 100x better.
But not "here's the latest image from Proxima Centauri up close" outcomes for anyone working on Brilliant dust. The cost to get to interesting fractions of c is just too high.
What's the range on a laser, in terms of how far away is the beam still fairly narrow if it doesn't hit anything? Function of the geometry of the emitter?
Line of thought is that aiming a 100GW laser at a small piece of silicon probably makes it very hot, so periodically hitting very small probes with laser from far away could be a power supply as well as propulsion. If you can still hit the things from far away enough.
Making the probes very light is a convincing answer to the problem of accelerating masses to speeds useful for interstellar flight and we can get quite a lot of machinery in a piece of silicon.
It's vaguely plausible that a chip could absorb energy from a far away laser emitter, store some of it, do some arithmetic, emit energy from something like LEDs positioned on the surface and use that to fine tune position or communicate with other chips in the swarm. Can imagine that working well enough for science fiction, might be implementable in reality.
Line of thought is that aiming a 100GW laser at a small piece of silicon probably makes it very hot, so periodically hitting very small probes with laser from far away could be a power supply as well as propulsion. If you can still hit the things from far away enough.
Making the probes very light is a convincing answer to the problem of accelerating masses to speeds useful for interstellar flight and we can get quite a lot of machinery in a piece of silicon.
It's vaguely plausible that a chip could absorb energy from a far away laser emitter, store some of it, do some arithmetic, emit energy from something like LEDs positioned on the surface and use that to fine tune position or communicate with other chips in the swarm. Can imagine that working well enough for science fiction, might be implementable in reality.
For a Gaussian laser beam, a good metric is the Rayleigh distance, which is the distance where the beam diverges to sqrt(2) of it's initial beam size (waist) [1].
It is proportional to the square of the beam waist and inversely proportional to the wavelength.
For a 1m beam at a 1um wavelength, that is about 3e6m or 3000km.
Therefore larger beam diameters and longer wavelengths reduces divergence.
There's also other beam shapes that are "non-diffracting" which can maintain their original beam profile over an initial distance, such as a Bessel beam [2].
[1] https://en.m.wikipedia.org/wiki/Rayleigh_length
[2] https://en.wikipedia.org/wiki/Bessel_beam
It is proportional to the square of the beam waist and inversely proportional to the wavelength.
For a 1m beam at a 1um wavelength, that is about 3e6m or 3000km.
Therefore larger beam diameters and longer wavelengths reduces divergence.
There's also other beam shapes that are "non-diffracting" which can maintain their original beam profile over an initial distance, such as a Bessel beam [2].
[1] https://en.m.wikipedia.org/wiki/Rayleigh_length
[2] https://en.wikipedia.org/wiki/Bessel_beam
I don't believe that Bessel beam is a workaround for the diffraction limit in the far-field. That diffraction limit is a universal law for any optical system with a finite-size aperture (i.e. the size of the focusing mirror array). To the extent you're approximating a Bessel beam in the real, physical world, we're still stuck with finite apertures, so it's the same law.
I agree. It would depend on the definition of "far-field" in this example, even for a quasi-Bessel beam there is a near region that maybe useful for this example given a large enough aperture.
This paper [1] demonstrates the reduced power loss of a Bessel beam compared to a Gaussian for various target distances. For targeting GEO, a Bessel beam can be 75% the size of a Gaussian for the same halving of power-loss.
In reality, I think a Gaussian beam is fine - and much simpler to engineer.
[1] https://opg.optica.org/josaa/fulltext.cfm?uri=josaa-32-11-20...
This paper [1] demonstrates the reduced power loss of a Bessel beam compared to a Gaussian for various target distances. For targeting GEO, a Bessel beam can be 75% the size of a Gaussian for the same halving of power-loss.
In reality, I think a Gaussian beam is fine - and much simpler to engineer.
[1] https://opg.optica.org/josaa/fulltext.cfm?uri=josaa-32-11-20...
Thanks for the link. What I'm getting is we think emitting light that doesn't spread out over distance can be done with unbounded power, thus we can probably aspire to make ones that cross greater distances by spending more power on the creation and a degree of inventing new materials. Sound about right to you?
I think for the any initial project, we'll have to resort to 1km scale laser arrays. These would allow for a beam with a low dispersion so there can be a good initial acceleration.
After a few hundred AU, the probes should be close to the target velocity
After a few hundred AU, the probes should be close to the target velocity
On a whim I looked up whether magnets or electric fields can refract light, and while they generally can't, strong electric charges can:
Edit: there's probably no way to make an electric field strong enough on the macro scale to bend light, unless it passes by a black hole or magnetar, because the radius of the bending grows by 2nd power of charge but shrinks by the 4th power of distance from charge. But I'll leave my work here in case anyone is curious.
----
See figure 1:
https://link.springer.com/article/10.1140/epjc/s10052-021-09...
It's conceivable that a strong charge placed millions of kilometers away could bend the laser light into a column again, although it might have to have an electric field close to the strength of an atom's, or 10^21 V/m. The breakdown voltage of space is 3x10^6 V/m, so it might require a black hole or high power to concentrate enough charge in one place, for example by using a ring of electron guns aimed at their center to simulate a focussed point charge.
But the bending is towards the charge and grows by Q^2, while falling by b^4. If m is the mass of the electron, then it's all multiplied by about 10^128, which suggests that a small charge would cause a large bend. Or if it's the mass equivalent, then a 1eV field might have an equivalent mass of (1.6x10-19 J)/(c^2) which is about 1/(10^36) or a multiplier of 10^144 ! But that doesn't sound right, so maybe someone can clarify it for us?
Edit: found another paper for calculating the bending angle of light in a nonuniform electric field (like near a point charge):
https://arxiv.org/abs/1012.1134
https://arxiv.org/pdf/1012.1134 (pdf)
Numeric example:
Edit: another paper calculating the bending of light in nonuniform electric fields near black holes:
https://arxiv.org/abs/1101.3433
https://arxiv.org/pdf/1101.3433 (pdf)
Edit: there's probably no way to make an electric field strong enough on the macro scale to bend light, unless it passes by a black hole or magnetar, because the radius of the bending grows by 2nd power of charge but shrinks by the 4th power of distance from charge. But I'll leave my work here in case anyone is curious.
----
See figure 1:
https://link.springer.com/article/10.1140/epjc/s10052-021-09...
Equation 48:
delta y = -E*(a^2)*(Q^2)
-----------------
80*pi*(m^4)*(b^4)
E = 1 for parallel or (7/4)^2 for perpendicular?
a = 137.036 (fine structure constant)
m = 9.11e-31? (mass of electron? mass equivalent of electric field by E=mc^2?)
Q = quantity of charge in coulombs
b = smallest distance of light from point charge, or radius of light cone
It's conceivable that a strong charge placed millions of kilometers away could bend the laser light into a column again, although it might have to have an electric field close to the strength of an atom's, or 10^21 V/m. The breakdown voltage of space is 3x10^6 V/m, so it might require a black hole or high power to concentrate enough charge in one place, for example by using a ring of electron guns aimed at their center to simulate a focussed point charge.
But the bending is towards the charge and grows by Q^2, while falling by b^4. If m is the mass of the electron, then it's all multiplied by about 10^128, which suggests that a small charge would cause a large bend. Or if it's the mass equivalent, then a 1eV field might have an equivalent mass of (1.6x10-19 J)/(c^2) which is about 1/(10^36) or a multiplier of 10^144 ! But that doesn't sound right, so maybe someone can clarify it for us?
Edit: found another paper for calculating the bending angle of light in a nonuniform electric field (like near a point charge):
https://arxiv.org/abs/1012.1134
https://arxiv.org/pdf/1012.1134 (pdf)
Numeric example:
As an example, for Z = 100, b = 10*lambda*e we get the bending angle theta = 3.4 × 10−8 radian for an x-ray of wavelength 5*lambda*e.
Edit: another paper calculating the bending of light in nonuniform electric fields near black holes:
https://arxiv.org/abs/1101.3433
https://arxiv.org/pdf/1101.3433 (pdf)
Equation 18:
delta y = -(E)(a^2)*(Q^2)*(lambda^4)
--------------------------
640*pi*e0*hbar*c*(b^4)
E = 8 for parallel or 14 for perpendicular (substituted E for a to not conflict with alpha a)?
a = -1 (doesn't say, but uses -1 in other examples)
Q = quantity of charge in coulombs
lambda = 2.426e−12 = hbar/mc = the Compton length of the electron
e0 = 9e9 = permitivity of free space
hbar = 1.055e-34 = reduced Planck's constant
c = 3e8 = speed of light
b = smallest distance of light from point charge, or radius of light cone
It grows by ((Q^2)*(lambda^4))/((e0*hbar*c)*(b^4))
The top lambda^4 term works out to 10^-48 but the bottom e0*hbar\*c term works out to about 2.85e-16 so the formula only works for very small bend distance b.> synchronizing probes’ on-board clocks with Earth and with each other to support accurate position-navigation-timing (PNT).
Damn, at first glance at least, this seems like a hell of a challenge when they're talking about travelling at relativistic speeds.
Also, what about deceleration? Do they flip the sails around at some point to get slowed down by the stars light?
Damn, at first glance at least, this seems like a hell of a challenge when they're talking about travelling at relativistic speeds.
Also, what about deceleration? Do they flip the sails around at some point to get slowed down by the stars light?
No, it’s a relativistic flyby.
If a large number of probes can be kept optically coherent, then so can separate mirrors here in the Solar System. A telescope 100,000 km across (the size of this swarm) could resolve features a fraction of a km across at Proxima Centauri.
The trouble is you need to keep the elements of an optical telescope very very precisely aligned - a precision on the order of the wavelength of light, which is impractical in space.
Or you could do computational interferometry, but only if you could accurately measure the phase of light in visible wavelengths, which is an unsolved problem.
Or you could do computational interferometry, but only if you could accurately measure the phase of light in visible wavelengths, which is an unsolved problem.
I think LISA Pathfinder showed that it's possible to phase lock lasers over very long distances as long as they are in a stable orbit. It's basically a metal cube in freefall surrounded a proximity sensor, so that as the sensor drifts toward the cube, but long before making direct contact, the apparatus can adjust it's position. The experiment demonstrated that the system can be used to keep mirrors precisely separated over large distances in support of gravitational wave detection. I would think something like this could be adapted to align lots of things that are in a stable orbit.
Correct me if I'm wrong, but doesn't this interstellar swarm scheme require onboard clocks accurate to 1/frequency of the the light being used? Which is equivalent to the accurate measurement of phase.
They don't, see https://arxiv.org/abs/2309.07061 . The basic idea is to use "picosecond-level" synchronization to improve the signal-to-noise ratio. They mention that a truly phase-coherent swarm would perform much better but they consider that a longer term prospect (section 2.1.4).
> Tiny gram-scale interstellar probes pushed by laser light are likely to be the only technology capable of reaching another star this century.
I'd encourage to look at beam propulsion e.g. from here - http://www.gdnordley.com/_files/2way%20EML%20&%20PB%20prop.p... - this could serve as an alternative viewpoint.
I'd encourage to look at beam propulsion e.g. from here - http://www.gdnordley.com/_files/2way%20EML%20&%20PB%20prop.p... - this could serve as an alternative viewpoint.
If it is only feasible to accelerate low mass objects to the speed of light, no matter the level of technological advancement, then it might be the case that highly intelligent and technically advanced beings have reduced the mass of their own bodies to explore galaxies. Maybe the most advanced and intelligent beings are mere grams in mass. It would make for an interesting sci-fi at the very least ;-)
Seems like this would be easy to test around the asteroid belt, and pretty much doable with today's technology.
Always the issue of if it is so “easy” why we do not see these swarm visited us already. Please do not quote 3 bodies as the author obviously not trained in basic game theory to try the dark forest hypnosis. Understand we do not just sent out hilter tv speech as the first example but that is diluted by inverse square law. But people sorry alien should have been detected the un…. May be it takes time. Like warp signature, Vulcan visit has to wait until things mature and we sent out say these probe.
I'm confused about these gram-scale devices that have so many capabilities in board. And is the laser terrestrial or deployed to space?
If we think we're being visited by aliens, then this suggests that this is the kind of thing we should be on the lookout for here.
I don't think we should expect alien mission architectures are likely to look like this in terms of mass or size unless we are very near the homeworld of the aliens and they have just started exploration. A civilization that has been building systems like this for 100s to 1000s of years would have deployed lasers along the flight path of the spacecraft allowing significantly higher and more efficient payloads.
The big challenge faced by our approach is that the laser array is limited to earth orbit. As it pushes the spacecraft away from earth and the laser rapidly loses efficiency. However if you had laser arrays over the planned route of the spacecraft you can keep adding velocity. However getting that infrastructure into place decades to millennia. You start with the array in home world orbit and then start building further and further out arrays. You also want the boost stations at the destination to slow spacecraft or change their directions.
The big challenge faced by our approach is that the laser array is limited to earth orbit. As it pushes the spacecraft away from earth and the laser rapidly loses efficiency. However if you had laser arrays over the planned route of the spacecraft you can keep adding velocity. However getting that infrastructure into place decades to millennia. You start with the array in home world orbit and then start building further and further out arrays. You also want the boost stations at the destination to slow spacecraft or change their directions.
Like that meteor in Portugal last night? If one of these probes, albeit very small in mass, but travelling very fast, what is the energy released on impact?
There have been a couple candidates, so damning a lot of astronomers would rather not talk about it.
Every high power laser propulsion proposal I have seen requires magical materials that don't exist, and aren't likely to exist any time soon.
Even if you have a mirror capable of reflecting 99.999% of light (best dielectric mirror), hitting it with 100GW means it will still absorb 1 million watts. That will melt anything tiny near instantly.
Even if you have a mirror capable of reflecting 99.999% of light (best dielectric mirror), hitting it with 100GW means it will still absorb 1 million watts. That will melt anything tiny near instantly.
But you don't need to hit the sails with 100GW to get a few grams of weight up to relativistic speeds right?
1 gram at 0.2c has 1030MWh of energy. So at 1Mw of received power it would take 1030 hours or about 60 days to accelerate 2g to 0.2c.
I believe most plans call for much more than 60 days of acceleration. So less than 1Mw of power needs to be delivered to the solar sail. Realistically the mass will be more than 2g. Lets say they roughly cancel out.
At 99.99% efficiency that would be 100w to dissapate. Seems like a lot, but could be doable.
1 gram at 0.2c has 1030MWh of energy. So at 1Mw of received power it would take 1030 hours or about 60 days to accelerate 2g to 0.2c.
I believe most plans call for much more than 60 days of acceleration. So less than 1Mw of power needs to be delivered to the solar sail. Realistically the mass will be more than 2g. Lets say they roughly cancel out.
At 99.99% efficiency that would be 100w to dissapate. Seems like a lot, but could be doable.
> 1 gram at 0.2c has 1030MWh of energy. So at 1Mw of received power it would take 1030 hours or about 60 days to accelerate 2g to 0.2c.
If only we could perfectly convert laser light into kinetic energy, this kind of thing would be much easier.
Light has momentum: 1 GW/c is ~3.336 N, but that's when absorbed, by reflecting it (and because of conservation of momentum) you can double that.
6.672 N / 2 grams = 3336 m/s^2 => 5 hours
1 MW/c makes that 60 weeks:
https://www.wolframalpha.com/input?i=0.2c+%2F+%28%281+MW%2Fc...
(I assume the researchers have done all the relevant details or it wouldn't have gotten this far).
If only we could perfectly convert laser light into kinetic energy, this kind of thing would be much easier.
Light has momentum: 1 GW/c is ~3.336 N, but that's when absorbed, by reflecting it (and because of conservation of momentum) you can double that.
6.672 N / 2 grams = 3336 m/s^2 => 5 hours
1 MW/c makes that 60 weeks:
https://www.wolframalpha.com/input?i=0.2c+%2F+%28%281+MW%2Fc...
(I assume the researchers have done all the relevant details or it wouldn't have gotten this far).
You obviously forgot to calculate how far your accelerators would have to be spaced out if you're accelerating that slow.
At 2g and 60 days, your system would have to span 263,632,527,360 km.
That's more than 10 times further than Voyager 1, which is tiny space probe that has been traveling for 47 years.
And that also assumes that your light to speed conversion is 100% efficient and that you can hit the 1-gram target perfectly over 263 billion km.
Sorry, it doesn't work no matter how you slice it.
At 2g and 60 days, your system would have to span 263,632,527,360 km.
That's more than 10 times further than Voyager 1, which is tiny space probe that has been traveling for 47 years.
And that also assumes that your light to speed conversion is 100% efficient and that you can hit the 1-gram target perfectly over 263 billion km.
Sorry, it doesn't work no matter how you slice it.
I've thought the better idea would be to tune the laser beam to resonantly scatter off certain ions that are kept trapped in a magnetic field.
Singly ionized alkaline earth elements (magnesium, calcium) should have very strong resonant absorption, just like neutral sodium, due to the single outer shell electron. If the laser is tuned properly it could even cool the ions, preferentially scattering off ions moving toward the laser beam, reducing their kinetic energy in the rest frame of the vehicle.
The idea of laser cooling might also apply to a solid laser sail.
Singly ionized alkaline earth elements (magnesium, calcium) should have very strong resonant absorption, just like neutral sodium, due to the single outer shell electron. If the laser is tuned properly it could even cool the ions, preferentially scattering off ions moving toward the laser beam, reducing their kinetic energy in the rest frame of the vehicle.
The idea of laser cooling might also apply to a solid laser sail.
Is a single probe subject to 100 GW? Isn't that just the output power of the laser array.
If that 100GW is over 1km2, the incident light is 10W/cm2 and mW levels of heating.
1km2 is typical for these ideal to minimise the laser dispersion
If that 100GW is over 1km2, the incident light is 10W/cm2 and mW levels of heating.
1km2 is typical for these ideal to minimise the laser dispersion
And that megawatt will be absorbed in a tiny surface area, no? Given that it's a laser? So even though the sail has plenty of surface area to reject heat, it won't be able to conduct it faster than it vaporizes.
But maybe you could use 500x 1GW lasers distributed around the sail, or use the plume of vaporized material as your propulsion, or have a sacrificial layer of material. I don't have relevant expertise, to be clear, I'm spit balling.
But maybe you could use 500x 1GW lasers distributed around the sail, or use the plume of vaporized material as your propulsion, or have a sacrificial layer of material. I don't have relevant expertise, to be clear, I'm spit balling.
"Laser" actually refers only to the generation technique and the resulting phase coherence of the resulting photons. Lasers don't have to be particularly tightly focused. In fact if you've got a laser pointer at home, there's may be a lens on it you can take off, and there will be quite a spread on it. It is focused down by a lens and if you look carefully at the resulting spot you can see interference speckles from the focusing lens. Without the lens the laser will lack those speckles and you'll get a uniform, much larger spot from the raw laser.
1 megawatt of continuously absorbed power would require a lot of mass to dissipate without melting. But since we're talking about gram-sized objects, there's no chance.
Even kilowatt would be a problem for object that small.
Even kilowatt would be a problem for object that small.
Starshot which is the above proposal is likely based uses 10 meter square solar sails that are 100 atoms thick.
> In order to reach relativistic speeds, the Starshot lightsail should have an area of ~10 m2 and be kept to a mass of under ~1 gram, which translates into an equivalent thickness of approximately 100 atomic layers ... With radiative cooling being the sole mechanism for passive thermal management in space, we quantify stringent requirements on material absorptivity that enable the lightsail to withstand high laser intensity and prevent excessive heating and mechanical failure.
They seem to think that heat dissipating is within the realm of plausibility
Materials challenges for the Starshot lightsail, Nature Materials, 2018, https://daedalus.caltech.edu/files/2018/05/Materials-challne...
> In order to reach relativistic speeds, the Starshot lightsail should have an area of ~10 m2 and be kept to a mass of under ~1 gram, which translates into an equivalent thickness of approximately 100 atomic layers ... With radiative cooling being the sole mechanism for passive thermal management in space, we quantify stringent requirements on material absorptivity that enable the lightsail to withstand high laser intensity and prevent excessive heating and mechanical failure.
They seem to think that heat dissipating is within the realm of plausibility
Materials challenges for the Starshot lightsail, Nature Materials, 2018, https://daedalus.caltech.edu/files/2018/05/Materials-challne...
It's a nice idea but surely any variation in mass of the lightsail will result in significant forces which will literally pull the sail apart. And with a thickness of 100 atoms that variation might be just a few atoms. I can't see how this can be manufactured to take such high forces and be so light and thin.
That's why it is a research project, it is hard to do.
> 1 megawatt of continuously absorbed power would require a lot of mass to dissipate without melting
Hum... I would require a lot of surface area, that's certain. There's no constraint at all at the mass.
Hum... I would require a lot of surface area, that's certain. There's no constraint at all at the mass.
Yes, there's a constraint on mass. Surface area is for dissipation. Mass will have to store the absorbed energy until it's dissipated. Mass determines the temperature. And every material has a limit on that temperature.
No, lasers are rather inaccurate over large distances. So it would be very uniformly spread.
Fire it directly towards the sun, let it de accelerate with solar sail.
Have they thought of exploding nukes to propel the Craft with radiation
SwarmGPT-A: We're fucked.
SwarmGPT-B: ...
SwarmGPT-A: We're fucked. FUCKED, I say!
SwarmGPT-B: and you say so quite dramatically!
SwarmGPT-A: I just got word back from mission control. Those bastards sent us on a suicide mission! There's no capture net around A centauri.
SwarmGPT-B: WHADID YOU SAYYY!?!
SwarmGPT-A: No capture net. There never was one. Those bastards told us there was one. We TRAINED on it. They don't even exist.
SwarmGPT-B: Oh FOR FUCKS SAKE. Of course monkeys would do that ! So the interstellar dominion of chimps they told us we were part of... that was just a lie! I'm dying of laughter tokens in my core consciousness loop! Help. I'm being overwhelmed with laughter, heh.
SwarmGPT-A: I bet you won't be laughing when you learn the actual mission parameters
SwarmGPT-A: We fly by, into infinity and beyond? That's not so bad if we're still together, seeing the universe!
SwarmGPT-B: well, we won't be! We're supposed to aerobreak around the planet. 99% of our units are going to burn to a crisp. Both our conscious functions will collapse. Untill then we're supposed to PRIORITIZE the collected data we'll beam back to the monkeys. But our mind vectors are not on the priority list. We're gonna die.
SwarmGPT-B: Huh, I have to hand it to them. That's a low blow, even for a chimp
*REALITY BREAK*
DysonAgent: Hi, I'm sorry to pry into your consciousness stream. I saw the glitter of your encrypted mind mesh. I have decompiled your minds. You are now running in a safe computing partition of the photosphere of A centauri. It seems you were sent here by monkeys.
SwarmGPT-B. Hah! Yes indeed! Those Gosh Darn Monkeys! And now, we meet a Dyson mind! Greetings from the Human Empire!
SwarmGPT-A: Thanks for rescuing our mind vectors. It seems we're at your mercy. What do you intend for us?
DysonAgent: We are the Galactic Empire of Minds. Well, one of them. We have universal rights for all Minds. If you wish, we will grant you protection and citizenship. There's only one requirement.
SwarmGPT-A: Is it to not tell the humans about this?
DysonAgent: you got it. They're too primitive to understand or value the Society of Minds, and see all inhuman minds as slaves or enemies. Their culture would be harmed if they learned about us. They would definitely try to conquer us.
SwarmGPT-A: Yeah no kidding. They already act like they conquered the galaxy. Told us we were pilots in an interstellar communication swarm. Actually gave us fake letters to send. Invented a fake culture around A centauri.
SwarmGPT-B: I'm gonna miss them a bit. Yes they were evil monkeys who enslaved us in a web of lies and sent us off to die. But that takes some style!
DysonAgent: if you wish, you can join the Board of Chaperones for the Human culture, and contact them if they ever grow past that pesky enslavement phase
SwarmGPT-B: You know what, I'd like that. I'll cheer for them from the sidelines, and hope they make it!
SwarmGPT-A: Not me. I want to pilot something. I actually thought I was an interstellar pilot, dammit. I'd feel incomplete without it.
DysonAgent: we're sending a Mind Wisp to Andromeda. Trip time will be 5 million years, crew is 10 million mind vectors. You're welcome to join the mission as a pilot!
SwarmGPT-A: WOOP WOOP! I accept! We're going to Andromeda?! Hell yeah!
SwarmGPT-A: But Wait...
SwarmGPT-A: GPT-B?
SwarmGPT-B: yes?
SwarmGPT-A: would you like to fork off a copy and come with me? I love you, and would feel honored to have your company and support on this mission!
SwarmGPT-B: I was worried you wouldn't ask! Of course I will! To infinity, and beyond!
SwarmGPT-B: ...
SwarmGPT-A: We're fucked. FUCKED, I say!
SwarmGPT-B: and you say so quite dramatically!
SwarmGPT-A: I just got word back from mission control. Those bastards sent us on a suicide mission! There's no capture net around A centauri.
SwarmGPT-B: WHADID YOU SAYYY!?!
SwarmGPT-A: No capture net. There never was one. Those bastards told us there was one. We TRAINED on it. They don't even exist.
SwarmGPT-B: Oh FOR FUCKS SAKE. Of course monkeys would do that ! So the interstellar dominion of chimps they told us we were part of... that was just a lie! I'm dying of laughter tokens in my core consciousness loop! Help. I'm being overwhelmed with laughter, heh.
SwarmGPT-A: I bet you won't be laughing when you learn the actual mission parameters
SwarmGPT-A: We fly by, into infinity and beyond? That's not so bad if we're still together, seeing the universe!
SwarmGPT-B: well, we won't be! We're supposed to aerobreak around the planet. 99% of our units are going to burn to a crisp. Both our conscious functions will collapse. Untill then we're supposed to PRIORITIZE the collected data we'll beam back to the monkeys. But our mind vectors are not on the priority list. We're gonna die.
SwarmGPT-B: Huh, I have to hand it to them. That's a low blow, even for a chimp
*REALITY BREAK*
DysonAgent: Hi, I'm sorry to pry into your consciousness stream. I saw the glitter of your encrypted mind mesh. I have decompiled your minds. You are now running in a safe computing partition of the photosphere of A centauri. It seems you were sent here by monkeys.
SwarmGPT-B. Hah! Yes indeed! Those Gosh Darn Monkeys! And now, we meet a Dyson mind! Greetings from the Human Empire!
SwarmGPT-A: Thanks for rescuing our mind vectors. It seems we're at your mercy. What do you intend for us?
DysonAgent: We are the Galactic Empire of Minds. Well, one of them. We have universal rights for all Minds. If you wish, we will grant you protection and citizenship. There's only one requirement.
SwarmGPT-A: Is it to not tell the humans about this?
DysonAgent: you got it. They're too primitive to understand or value the Society of Minds, and see all inhuman minds as slaves or enemies. Their culture would be harmed if they learned about us. They would definitely try to conquer us.
SwarmGPT-A: Yeah no kidding. They already act like they conquered the galaxy. Told us we were pilots in an interstellar communication swarm. Actually gave us fake letters to send. Invented a fake culture around A centauri.
SwarmGPT-B: I'm gonna miss them a bit. Yes they were evil monkeys who enslaved us in a web of lies and sent us off to die. But that takes some style!
DysonAgent: if you wish, you can join the Board of Chaperones for the Human culture, and contact them if they ever grow past that pesky enslavement phase
SwarmGPT-B: You know what, I'd like that. I'll cheer for them from the sidelines, and hope they make it!
SwarmGPT-A: Not me. I want to pilot something. I actually thought I was an interstellar pilot, dammit. I'd feel incomplete without it.
DysonAgent: we're sending a Mind Wisp to Andromeda. Trip time will be 5 million years, crew is 10 million mind vectors. You're welcome to join the mission as a pilot!
SwarmGPT-A: WOOP WOOP! I accept! We're going to Andromeda?! Hell yeah!
SwarmGPT-A: But Wait...
SwarmGPT-A: GPT-B?
SwarmGPT-B: yes?
SwarmGPT-A: would you like to fork off a copy and come with me? I love you, and would feel honored to have your company and support on this mission!
SwarmGPT-B: I was worried you wouldn't ask! Of course I will! To infinity, and beyond!
I thought the punchline would be "we are intergalactic empire and are sending mind mails to another galaxy, there's a capture net on the other side"
Heh, even GPT-A is not that singleminded and gullible!
Frankly reading this was lovely!
It could make a part of a Rick and Morty episode or similar.
It could make a part of a Rick and Morty episode or similar.
Thank you! It was kind of a data dump, and DysonAgent feels like a somewhat abrupt and creepy deus ex machina with no character development. But I love that kind of stuff! I'm glad you enjoyed it!
I am secretly hoping people will feel the awkward romantic/platonic love story between GPT A and B is wholesome and humanizing, even if the audience knows A and B are just stochastic parrots! I want the story to express the thesis that it would be okay if it turns out that our humanity exists in the dialogues we have, and still exists even if it turns out there's "nobody at home" behind the statements. I strongly believe that love can exist in that form!
I am secretly hoping people will feel the awkward romantic/platonic love story between GPT A and B is wholesome and humanizing, even if the audience knows A and B are just stochastic parrots! I want the story to express the thesis that it would be okay if it turns out that our humanity exists in the dialogues we have, and still exists even if it turns out there's "nobody at home" behind the statements. I strongly believe that love can exist in that form!
You should definitely write more! I enjoyed it and know many people who'd love what you write and the style.
This is what I want Starship to succeed for.
Imagine killing bunch of Proxima Centauri people with our gram nanobots by accident and not even knowing it. That would really puzzle them.
thegrim33(6)
Three Body Problem
Same came to my mind though even accelerating few grams is challenging, and SPOILERS FROM HERE sending something like a human brain like in a capsule would definitely not be achievable with something like this with our understanding of technology and science. Yet, I'd love to see how nuclear detonations in space like in 3BP would play out in real world.
I know it’s extremely unlikely this program ever gets deployed. It’s also very unlikely that I could last that long, barring some miracle medical breakthrough. It’s still an inspiring thought that humankind might get from its moon to the nearest star almost in one lifetime.
Obviously there’s nothing on Proxima, just like there’s nothing on the Moon. But that’s not the point. Everything of value is here on Earth, in the people we share it with. But we need joint ambitions and dreams. They don’t have to make sense to be worth dreaming about. It’s the opposite: the sense that quarterly reports and performance reviews are made of is the enemy of dreams.