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6 minutes ago, Robotengineer said:

And what does the amount of power it took a fictional time machine to time-travel have to do with anything?

Because when we first saw it, "1.21 JIGGAWATTS MARTY!", sounded like some preposterous made-up amount of energy. But now its like "Meh, I've read of three seperate projects which consume more power just today..."

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49 minutes ago, monstah said:

You're probably missing the point that they plan to zap each nanoprobe with 80 times as much power as it took the DeLorean to time-travel, for a few minutes.

I know that, but you could stuff an uninhabited ISS with 400 tons of Li+ batteries, and add a laser array you would have much better tracking.

Remember that d = 1/2AT^2 and accuracy is dependent on distance, if you start at 35km away you start with a handicap. Then add to that your laser beams are heating up, going through the atmosphere and sitting on a surface that is moving at 1.6 km per second and changing its theta (0.0042 degrees per second for 100 seconds). If you put the target on the ISS it naturally does not rotate, so its lasers are going to remain fixed on the target if that target is shot just shy of strait out. Tracking becomes 1000 times easier.

They said this in the news conference, they are going to have to improve their ability to deal with surface disruptions 1000 times better than current.

 

 

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On 13/4/2016 at 1:05 PM, PB666 said:

To do this you would have to have the capacity to generation 100 gigawatts of power in say the 15 days in which the moon faces the sun and store it.

100 gigawatts of power in 15 days?
Ok, one thing is power... the other is energy needed.
You just need 100gw over 100 seconds =  2,7 gwh, you need to launch one sail every 1 day approx (due communication relay, reach and margin of error)
Then to generate that amount of energy in that time you may need a nuclear plant of 120 mw if these laser are 100% efficient, or 240mw if they are 50% efficient.
You can storage that in capacitors (they can hold that charge for a day and you need a fast discharge)
The amount and cost it will depend on the technology... a lot of new technologies are making breakthroughs on that front, so it will be kinda pointless make estimations with today values.

Solar panels with 15 days of storage on the moon (of course hydrogen is the obvious choice here as energy storage, rule: you need to storage energy for more than 3 or 4 hours, then hydrogen), but moon does not seems the best choice due storage and all the things you need to sent there, more taking into account what they said, that atmosphere laser-distortion is solveable with correction optics in the same way that telescopes do it, choosen the right wavelength and shooting from the top of a mountain seems enough. 

3 hours ago, PB666 said:

Late :)

Also my point also work outside of the event horizon or even with earth gravity..  If forces or accelerations are uniform in all your body, there is no problem, the pain or discomfort comes with a differential. Gas pockets inside circuits can be a major problem.

Edited by AngelLestat

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6 hours ago, PB666 said:

0.2c in 100 seconds, not a day. the G force is 60k that is 600 km/sec^2.

Whoa!

What material they propose to make the sail out of?

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19 minutes ago, Shpaget said:

Whoa!

What material they propose to make the sail out of?

Remember, the probe weighs 1gram, the sail only has to be able to support 60kg (at 1earth G). It will have to be very light and very strong for sure, but not magic strong and light. Just for one material example of the top of my head - the claws of a mantis shrimp (yes, they are relevant to almost any post) accelerate at 10,000G - we won't make the sail out of chitin, we will make it out of something specifically tailored to suit, but the material properties are available.

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2 hours ago, Robotengineer said:

And what does the amount of power it took a fictional time machine to time-travel have to do with anything?

Has to do with the fact that you need to generate quite a lot of energy, and would need quite some equipment. Have you seen the (sure, artwork) depictions of the lasers shooting up? Like, many, huge antennas? Like I said, that's an artwork depiction, but can you imagine hauling that sort of thing to the ISS just to be above ground? Sounds like a job for Whackjob.

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24 minutes ago, p1t1o said:

Remember, the probe weighs 1gram,

A battery, camera, electronics, radio... no way to squeeze that into 1 gram.

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Don't know how many of you read this stuff, but Robert L. Forward used the "giant laser beamed power" idea in his book Rocheworld (1982/1990 revised) and came up with perhaps the most important reason why it might not work -- politics. In the book, they send the ship off to Barnard's Star with beamed power, then they are supposed to beam more power later to decelerate the ship. Except they get a Senate which is deadlocked and a troubled economy and a taxpayer revolt (sound familiar?) and they can't get the authorization to spend the money to beam the power for the deceleration phase.

Edited by mikegarrison

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1 hour ago, AngelLestat said:

100 gigawatts of power in 15 days?
Ok, one thing is power... the other is energy needed.
You just need 100gw over 100 seconds =  2,7 gwh, you need to launch one sail every 1 day approx (due communication relay, reach and margin of error)
Then to generate that amount of energy in that time you may need a nuclear plant of 120 mw if these laser are 100% efficient, or 240mw if they are 50% efficient.
You can storage that in capacitors (they can hold that charge for a day and you need a fast discharge)
The amount and cost it will depend on the technology... a lot of new technologies are making breakthroughs on that front, so it will be kinda pointless make estimations with today values.

Solar panels with 15 days of storage on the moon (of course hydrogen is the obvious choice here as energy storage, rule: you need to storage energy for more than 3 or 4 hours, then hydrogen), but moon does not seems the best choice due storage and all the things you need to sent there, more taking into account what they said, that atmosphere laser-distortion is solveable with correction optics in the same way that telescopes do it, choosen the right wavelength and shooting from the top of a mountain seems enough. 

Late :)

Also my point also work outside of the event horizon or even with earth gravity..  If forces or accelerations are uniform in all your body, there is no problem, the pain or discomfort comes with a differential. Gas pockets inside circuits can be a major problem.

 

The problem with falling into the black hole is the differential energy remember that work = force * distance.

Lets say you have a sun massed black hole  2e30 kg at 3000 meters . the gravity between say 3000 meters and 3002 meters the height of a human standing up is 1.334E20/9000000 is 1.48024E13 - 1.48222E13 = 1.98E10N/kg of mass

Lets say a human head weighs a kilogram, and can with pulling lift 2 inches (0.04 meters) then the work exerted would be 800,000,000 joules, that energy would be applied to what every force tried to stop further separation. So yeah a just before you get the black hole your parts would tear apart or burn up (probably both) .

Most black holes that we know of are many 1000s times the size of the sun, so that the force generated on entry would be considerable greater.

As for the calcualtion it looks like their estimate of 100 GW would be for a sub gram sized object. 60000 g from 100GW would be about a .5 gram target.  The amount of total energy would be substantially greater. This makes both an earth and lunar launch considerably more difficult. For the moon it might require 40000 tons of lithium ion batteries, however ISRU could probably make nickle based batteries on site.

 

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1 hour ago, Shpaget said:

A battery, camera, electronics, radio... no way to squeeze that into 1 gram.

Preaching to the choir buddy, but thats the plan as laid out apparently, I doubt its going to be harder than building a stupendous death ray to power it.

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1 hour ago, PB666 said:

The problem with falling into the black hole is the differential energy remember that work = force * distance.

I know the spaghettification effect, but I did not give distance or black hole mass neither acceleration, because I just wanted to make a point that is not related to black holes.  But well, if we are talking of prevent spaghettification, then we need big black holes, at certain distance outside from the even horizon (so we dont have problem with no proven theories) to produce huge accelerations without any harm to the subject (with a no active black hole, so radiation is not an issue neither) Happy? XD

1 hour ago, PB666 said:

As for the calcualtion it looks like their estimate of 100 GW would be for a sub gram sized object. 60000 g from 100GW would be about a .5 gram target.  The amount of total energy would be substantially greater. This makes both an earth and lunar launch considerably more difficult. For the moon it might require 40000 tons of lithium ion batteries, however ISRU could probably make nickle based batteries on site.

Lets see:

F = 2P/c  (photons bouncing force)

F= 200000000000 / 300000000

666 Newtons

This give me 1.13 grams..  (maybe you forget to multiply by 2, due bouncing)
But not sure if this value is right.. it seems very low..  You are sure the power requirement is 100 gw for the laser?

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7 hours ago, Shpaget said:

Whoa!

What material they propose to make the sail out of?

carbon nanotubes 3 atomic layers thick or some mumbo-jumbo like that, thats one of the technical details to be worked out.
Apparently if can absorb the light, its going to get freaky hot if its a meter and 300GW is being dissipated over it.

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3 hours ago, AngelLestat said:

I know the spaghettification effect, but I did not give distance or black hole mass neither acceleration, because I just wanted to make a point that is not related to black holes.  But well, if we are talking of prevent spaghettification, then we need big black holes, at certain distance outside from the even horizon (so we dont have problem with no proven theories) to produce huge accelerations without any harm to the subject (with a no active black hole, so radiation is not an issue neither) Happy? XD

Lets see:

F = 2P/c  (photons bouncing force)

F= 200000000000 / 300000000

666 Newtons

This give me 1.13 grams..  (maybe you forget to multiply by 2, due bouncing)
But not sure if this value is right.. it seems very low..  You are sure the power requirement is 100 gw for the laser?

You can't approach the speed of light unless your near the Schwartzfield radius. Even if you come to the hill sphere with near speed of light, because of time dilation and mass increase you would still be very close to that radius.

You can see the rebroadcast, I caught only the last 2/3rds of the live cast.

The are using carbon nanotubes, photons won't bounce, probably burn up, but you never know what new technology they will employ.

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Did they say how they were going to power the probe module? 1 gram seems really tight, and the only battery I know that might last that long are betavoltaic batteries from pacemakers, but I'm not sure that will mass under 1 gram. Maybe if they upped the probe mass to ten grams it might be possible. 

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1 hour ago, PB666 said:

You can't approach the speed of light unless your near the Schwartzfield radius. Even if you come to the hill sphere with near speed of light, because of time dilation and mass increase you would still be very close to that radius.

ok, right, but the context was just: big uniform accelerations = no damage.. 

1 hour ago, PB666 said:

You can see the rebroadcast, I caught only the last 2/3rds of the live cast.

The are using carbon nanotubes, photons won't bounce, probably burn up, but you never know what new technology they will employ.

They need to bounce or it will evaporate due heat XD
That is the easy part, you can choose the frequency of the laser, so if you make quarter wavelength holes in the sail, the light will bouce at 100% if they are perfect, or 99.9 if they are not (but that it would be enough to survive.

I was reading in some sites, it seems the sail is 4 m of diameter.. or 4m2, not sure.
One thing they dont mention, is that they need to make a special shape to make this sail self focus (auto riding the beam), if they get close to the edge of the beam, the shape and reflection force the sail to stay in the center of the beam.
Maybe regulating the spinning speed can be accomplished.
 

22 minutes ago, lobe said:

Did they say how they were going to power the probe module? 1 gram seems really tight, and the only battery I know that might last that long are betavoltaic batteries from pacemakers, but I'm not sure that will mass under 1 gram. Maybe if they upped the probe mass to ten grams it might be possible. 

I guess they will use micro nuclear components

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18 minutes ago, AngelLestat said:

ok, right, but the context was just: big uniform accelerations = no damage.. 

They need to bounce or it will evaporate due heat XD
That is the easy part, you can choose the frequency of the laser, so if you make quarter wavelength holes in the sail, the light will bouce at 100% if they are perfect, or 99.9 if they are not (but that it would be enough to survive.

I was reading in some sites, it seems the sail is 4 m of diameter.. or 4m2, not sure.
One thing they dont mention, is that they need to make a special shape to make this sail self focus (auto riding the beam), if they get close to the edge of the beam, the shape and reflection force the sail to stay in the center of the beam.
Maybe regulating the spinning speed can be accomplished.
 

I guess they will use micro nuclear components

at 600000 m/s not only does the laser targeting need to be perfect, but the sail has to be exactly positioned, otherwise game-over.

They said the sail could be made from carbon nanotubes or carbon-fiber, flective, nope.

 

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1 hour ago, PB666 said:

at 600000 m/s not only does the laser targeting need to be perfect, but the sail has to be exactly positioned, otherwise game-over.

That is the easy part.. the hard part is to self focusing the sail inside the beam, you could do that with special shape as I said like this but less drastic:

http://www.centauri-dreams.org/?p=33450

1 hour ago, PB666 said:

They said the sail could be made from carbon nanotubes or carbon-fiber, flective, nope.

It does not matter the material, but I found the original site of this project  (when i was searching for an quarter wave example for you), here is explained:

http://www.breakthroughinitiatives.org/index.php?controller=Forum&action=viewforum&id=5&page=1

Graphene is also in consideration, as you can see you can make a mirror with different techniques, holes quarter wave, or quarter wave dielectric way.

Just now, insert_name said:

I must ask what kind of science would these probes do

Almost everything you need, each sail has a different science instrument, lets imagine than the first 100 ships had a camera, then you can use another instrument in the next 100 ships

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7 minutes ago, insert_name said:

I must ask what kind of science would these probes do

As far as I can tell, there might not be much. It's supposed to accelerate to 0.2c and stay at that. A flyby of Alpha Centauri at relativistic speeds will not leave much time for science. A few hours at Earthlike or less range. I could see relativity experiments done with this but not much astronomy related things. Pictures, magnetic field measuring. It can't study planets because by the time it can actually see planets to study, it will not have told us until 4 years after it leaves the star system. We can't tell it to study them in more detail because we don't know if they exist, and giving it preprogrammed instructions to study anything that looks like a planet might cause a significant glitch. With eight years back-and-forth communication, we can't fix glitches in a sane timeframe.

I would also like to see them focus ultra powerful lasers on a tiny sail weighing mere grams traveling at relativistic speeds straight away from them. By the time they are done with the lasers it will be past the Moon at least. Consider also that it is also probably less than a foot wide and needs to have the lasers PERFECTLY balanced on it so it doesn't spin ridiculously. 

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I don't understand how a nano-satellite is supposed to beam data to earth from +4ly away. It takes a decent sized antenna/transmitter to go from Earth to Mars, and the whole probe was only supposed to be like the size of a quarter, right? I didn't watch the talk, did they talk about that at all?

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15 minutes ago, The Yellow Dart said:

I don't understand how a nano-satellite is supposed to beam data to earth from +4ly away. It takes a decent sized antenna/transmitter to go from Earth to Mars, and the whole probe was only supposed to be like the size of a quarter, right? I didn't watch the talk, did they talk about that at all?

Join the club, I will throw this one out, quantum entanglement. . . . .ducking and running.

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There are multiple issues that arise from the small size. Cameras and radio antennas require certain physical size to be of practical use. The laws of physics dictate that. You can't have a telescope with a tiny lens that performs well. Diffraction limits the minimum size.

The same goes for antenna. To achieve optimal performance (and that would certainly be necessary with such a small platform), the antenna needs to have the physical size that is matched to the wavelength of the radio used. But even if that was not an issue, consider this:

The New Horizons probe, which recently showed us some pretty pictures of Pluto, uses a 2.1 meter dish antenna. Pluto is between 2.3 and 7.5 billion kilometers from Earth. This distance is in the ballpark of what this little interstellar probe is supposed to travel in one day. (0.2 c = 300 000 * 3600 * 24 * 0.2 = 5 billion km).

So even if they launch a probe each day and use them as relays, they need at least New Horizon type radio equipment to transmit pretty pictures back home.

That is, of course not considering the fact that the receiving end of the New Horizon transmissions is not a tiny probe, but an array of 14 antennas all at least 34 m in diameter.

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1 hour ago, Shpaget said:

There are multiple issues that arise from the small size. Cameras and radio antennas require certain physical size to be of practical use. The laws of physics dictate that. You can't have a telescope with a tiny lens that performs well. Diffraction limits the minimum size.

Couldn't you use multiple probes in a kind of interferometer-style array? Both for the radio antennae and the optical cameras? I've heard of it being done with both radio and visible spectra but don't know much about limitations.

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21 minutes ago, p1t1o said:

Couldn't you use multiple probes in a kind of interferometer-style array? Both for the radio antennae and the optical cameras? I've heard of it being done with both radio and visible spectra but don't know much about limitations.

Not really. Interferometry works if each of them can capture the thing first. Now if phone cameras do weight 1 gram with all the chips and whatnot (which I doubt), using a few thousand phone camera might work, but what about the light gathering power ? It's not going to add up. Also, remember about noise...

And then you need the antenna. You'll need a few million of super short dipole antenna. Maybe you can use evolved antennas, but the power requirement will still be massive too...

--------

The more I saw of the details, the more skeptic I become...

But, you know. Large hopes for anything breakthrough as long as it's not harming anyone (like Solar FREAKIN' Roadways or other stupendous gimmick).

Edited by YNM

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3 hours ago, YNM said:

Not really. Interferometry works if each of them can capture the thing first. Now if phone cameras do weight 1 gram with all the chips and whatnot (which I doubt), using a few thousand phone camera might work, but what about the light gathering power ? It's not going to add up. Also, remember about noise...

And then you need the antenna. You'll need a few million of super short dipole antenna. Maybe you can use evolved antennas, but the power requirement will still be massive too...

--------

The more I saw of the details, the more skeptic I become...

But, you know. Large hopes for anything breakthrough as long as it's not harming anyone (like Solar FREAKIN' Roadways or other stupendous gimmick).

Yeah its not like a big giant laser would actually harm anyone (speaking from the big underground cave i currently digging for no particular reason) :rolleyes:

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