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Post by Kerr on Jun 22, 2017 16:33:54 GMT
Hello! I want to talk about Weaponized Laser Sails, usually Laser sail generate way to low thrust to be weaponized, but using Photon recycling we can increase the thrust immensely. At a NASA Program a Photonic Thruster was demonstrated that was able to amplify the laser thrust by 1000x. Using this information we can calculate some number. One newton recoil requires 300MW. An Laser Sail needs 150MW per Newton. Using two Highly reflective mirrors and gain medium the Laser power can we heavily amplified. Acceleration: 667km/s² Acceleration Time: 42s Acceleration Distance: 300Mm Velocity: 14Mm/s Mass: 1g Size: 16m² Energy: 100 GJ Propulsion: 40% Efficient 250MW Ce:LLF Laser (100MW Output) Firerate: 1.33 RPM Beam Power: 100GW Reflectivity: 99.999% Heating: 60kW/m² Note: For such a range the laser requires an focusing mirror 7m in Diameter. Some experiments achieved 20,000x photon bounces, and with MIT Dielectric reflectors up to 100,000 bounces are possible.
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Post by bigbombr on Jun 22, 2017 17:34:59 GMT
Hello! I want to talk about Weaponized Laser Sails, usually Laser sail generate way to low thrust to be weaponized, but using Photon recycling we can increase the thrust immensely. At a NASA Program a Photonic Thruster was demonstrated that was able to amplify the laser thrust by 1000x. Using this information we can calculate some number. One newton recoil requires 300MW. An Laser Sail needs 150MW per Newton. Using two Highly reflective mirrors and gain medium the Laser power can we heavily amplified. Acceleration: 20Mm/s² Acceleration Time: 1,4s Acceleration Distance: 10Mm Velocity: 14Mm/s Mass: 1g Size: 1m² Energy: 100 GJ Propulsion: 30% Efficient 10GW Laser (3GW Output) Firerate: 40 RPM Some experiments achieved 20,000x photon bounces, and with MIT Dielectric reflectors up to 100,000 bounces are possible. Photon cycling means you have to catch photons reflected by the sail and reflect them back on the sail. This can easily be done in a lab where the sail and laser are only 20 cm or a few meters apart. Doing this at longer ranges is orders of magnitude harder. Doing this on a steering projectile is impossible, unless you wan to cover all possible directions the sail bounces light to while steering with mirrors.
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Post by Kerr on Jun 22, 2017 17:50:29 GMT
Hello! I want to talk about Weaponized Laser Sails, usually Laser sail generate way to low thrust to be weaponized, but using Photon recycling we can increase the thrust immensely. At a NASA Program a Photonic Thruster was demonstrated that was able to amplify the laser thrust by 1000x. Using this information we can calculate some number. One newton recoil requires 300MW. An Laser Sail needs 150MW per Newton. Using two Highly reflective mirrors and gain medium the Laser power can we heavily amplified. Acceleration: 20Mm/s² Acceleration Time: 1,4s Acceleration Distance: 10Mm Velocity: 14Mm/s Mass: 1g Size: 1m² Energy: 100 GJ Propulsion: 30% Efficient 10GW Laser (3GW Output) Firerate: 40 RPM Some experiments achieved 20,000x photon bounces, and with MIT Dielectric reflectors up to 100,000 bounces are possible. Photon cycling means you have to catch photons reflected by the sail and reflect them back on the sail. This can easily be done in a lab where the sail and laser are only 20 cm or a few meters apart. Doing this at longer ranges is orders of magnitude harder. Doing this on a steering projectile is impossible, unless you wan to cover all possible directions the sail bounces light to while steering with mirrors. "steering projectile" ? Why would I even want the sail to steer? I can just rotate my ship and start firing my linear shooting sails. If no thrust is imparted from the sides the sail will continue flying forward. I doesn't even have to be an normal sail, it can also be an focusing mirror, which allows greater control over the direction of the reflected photons.
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Post by bigbombr on Jun 22, 2017 18:00:45 GMT
Photon cycling means you have to catch photons reflected by the sail and reflect them back on the sail. This can easily be done in a lab where the sail and laser are only 20 cm or a few meters apart. Doing this at longer ranges is orders of magnitude harder. Doing this on a steering projectile is impossible, unless you wan to cover all possible directions the sail bounces light to while steering with mirrors. "steering projectile" ? Why would I even want the sail to steer? I can just rotate my ship and start firing my linear shooting sails. If no thrust is imparted from the sides the sail will continue flying forward. I doesn't even have to be an normal sail, it can also be an focusing mirror, which allows greater control over the direction of the reflected photons. Because of their low acceleration, photon sail projectiles are probably long range weapons, so you'd probably want your photon sail to correct it's course in flight. There are limits to sensor and turret precision. I was thinking more like using them as extreme (possibly relativistic) velocity, long range missiles. You seem to think about them like low acceleration, extreme velocity cannons. For short ranges, coilguns will hit the target faster. At long ranges, you'll need some course correction.
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Post by Kerr on Jun 22, 2017 18:11:23 GMT
"steering projectile" ? Why would I even want the sail to steer? I can just rotate my ship and start firing my linear shooting sails. If no thrust is imparted from the sides the sail will continue flying forward. I doesn't even have to be an normal sail, it can also be an focusing mirror, which allows greater control over the direction of the reflected photons. Because of their low acceleration, photon sail projectiles are probably long range weapons, so you'd probably want your photon sail to correct it's course in flight. There are limits to sensor and turret precision. I was thinking more like using them as extreme (possibly relativistic) velocity, long range missiles. You seem to think about them like low acceleration, extreme velocity cannons. For short ranges, coilguns will hit the target faster. At long ranges, you'll need some course correction. What? The sail has an acceleration of ten million meters per second. After 1.4 seconds it reached a velocity of 14 thousand kilometers per second. This Beam produces 20 kilonewtons of thrust. After 6000 bounces a photon thruster produces as much thrust per watt as an Ion engine. At 100,000 bounces it produces at much as a chemical engine.
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Post by bigbombr on Jun 22, 2017 18:55:23 GMT
Because of their low acceleration, photon sail projectiles are probably long range weapons, so you'd probably want your photon sail to correct it's course in flight. There are limits to sensor and turret precision. I was thinking more like using them as extreme (possibly relativistic) velocity, long range missiles. You seem to think about them like low acceleration, extreme velocity cannons. For short ranges, coilguns will hit the target faster. At long ranges, you'll need some course correction. What? The sail has an acceleration of ten million meters per second. After 1.4 seconds it reached a velocity of 14 thousand kilometers per second. This Beam produces 20 kilonewtons of thrust. After 6000 bounces a photon thruster produces as much thrust per watt as an Ion engine. At 100,000 bounces it produces at much as a chemical engine. That much bounces (6000 or more) doesn't seem credible. The most bounces produced in a lab is 20 (that I'm aware of). Can the sail survive such accelerations? And is this practical or energy-efficient (compared to a coilgun or direct HELfire)?
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Post by Kerr on Jun 22, 2017 19:08:26 GMT
What? The sail has an acceleration of ten million meters per second. After 1.4 seconds it reached a velocity of 14 thousand kilometers per second. This Beam produces 20 kilonewtons of thrust. After 6000 bounces a photon thruster produces as much thrust per watt as an Ion engine. At 100,000 bounces it produces at much as a chemical engine. That much bounces (6000 or more) doesn't seem credible. The most bounces produced in a lab is 20 (that I'm aware of). Can the sail survive such accelerations? And is this practical or energy-efficient (compared to a coilgun or direct HELfire)? Bounces: In a experiment they achieved 20,000 bounces. 1000x Bounces were used In a working 500KW Thruster. I watched an stream from a NASA presentation earlier, they said they achieved 20 bounces without really putting any effort to it. Acceleration: Yes, if you exclude electronics. The lighter the sail the more resistant it is against G-forces. This sail weights 1g and has a surface of 1m². It's just very thin graphene-metamaterial. + Efficiency: The energy efficiency is enormous. My proposed system is way more efficient that coilgun could fundamentally be. 1.4 sec 3GW beam power equals to 4.2GJ. Through the amplifying the sail will gain an kinetic energy of 100 GJ. This is up-scaled from the working photon thruster.
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Post by Enderminion on Jun 22, 2017 19:14:03 GMT
seems like a great way to push a guided weapons much faster and closer to the target
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Post by Kerr on Jun 22, 2017 19:18:57 GMT
seems like a great way to push a guided weapons much faster and closer to the target The same laser could push a 10kg payload to 141.4km/s and a 100kg one to 44.7km/s. Way beyond any practical missile Dv modelled in CoaDE.
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Post by n2maniac on Jun 23, 2017 6:00:04 GMT
Hello! I want to talk about Weaponized Laser Sails, usually Laser sail generate way to low thrust to be weaponized, but using Photon recycling we can increase the thrust immensely. At a NASA Program a Photonic Thruster was demonstrated that was able to amplify the laser thrust by 1000x. Using this information we can calculate some number. One newton recoil requires 300MW. An Laser Sail needs 150MW per Newton. Using two Highly reflective mirrors and gain medium the Laser power can we heavily amplified. Acceleration: 20Mm/s² Acceleration Time: 1,4s Acceleration Distance: 10Mm Velocity: 14Mm/s Mass: 1g Size: 1m² Energy: 100 GJ Propulsion: 30% Efficient 10GW Laser (3GW Output) Firerate: 40 RPM Some experiments achieved 20,000x photon bounces, and with MIT Dielectric reflectors up to 100,000 bounces are possible. That will deposit ~2GJ of heat onto the 1g mass over its 1.4s acceleration time. Assuming aluminum's specific heat capacity, that is ~2 billion Kelvin. Help us understand what type of highly reflective and highly precise 1g/m2 mirror can withstand that degree of heating.
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Post by Kerr on Jun 23, 2017 9:52:54 GMT
Hello! I want to talk about Weaponized Laser Sails, usually Laser sail generate way to low thrust to be weaponized, but using Photon recycling we can increase the thrust immensely. At a NASA Program a Photonic Thruster was demonstrated that was able to amplify the laser thrust by 1000x. Using this information we can calculate some number. One newton recoil requires 300MW. An Laser Sail needs 150MW per Newton. Using two Highly reflective mirrors and gain medium the Laser power can we heavily amplified. Acceleration: 20Mm/s² Acceleration Time: 1,4s Acceleration Distance: 10Mm Velocity: 14Mm/s Mass: 1g Size: 1m² Energy: 100 GJ Propulsion: 30% Efficient 10GW Laser (3GW Output) Firerate: 40 RPM Some experiments achieved 20,000x photon bounces, and with MIT Dielectric reflectors up to 100,000 bounces are possible. That will deposit ~2GJ of heat onto the 1g mass over its 1.4s acceleration time. Assuming aluminum's specific heat capacity, that is ~2 billion Kelvin. Help us understand what type of highly reflective and highly precise 1g/m2 mirror can withstand that degree of heating. Breakthrough starshot uses a gram-scale probe with a 16m² Sail, the sail has to withstand 100GW (6.25GW/m²) of power. So I proposed that my Photon-KKV uses the same Graphene based metamaterial. Scaled it down to a 1m² sail with an 3GW Photonic Thruster.
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Post by shiolle on Jun 23, 2017 12:35:38 GMT
Using two Highly reflective mirrors and gain medium the Laser power can we heavily amplified... Acceleration: 20Mm/s² The mirror needs to be both 100% reflective and 100% smooth. Any imperfection in the mirror will vaporize the sail. Any wrinkle will tear it apart. All these qualities need to be maintained under 2 million g acceleration. Yes, totally legit.
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Post by Kerr on Jun 23, 2017 12:58:59 GMT
Using two Highly reflective mirrors and gain medium the Laser power can we heavily amplified... Acceleration: 20Mm/s² The mirror needs to be both 100% reflective and 100% smooth. Any imperfection in the mirror will vaporize the sail. Any wrinkle will tear it apart. All these qualities need to be maintained under 2 million g acceleration. Yes, totally legit. 1) Photon pressure = 20kPA, the yield strength of the sail is over 100 GPa, an difference of over 6 magnitudes. 2) "100% reflective and 100% smooth." In that case the thrust will be amplified by infinity. But as soon they start moving apart the doppler-effect will limit the amount of bounces. 99.9% Reflectivity is more than sufficient for 1000x bounces. Imperfections are avoidable with sufficient effort. We also can increase the size from 1m² to 16m². Which would (If we use an meta-graphene mirror that's few hundred atoms thick) still weigh roughly 1g. Put decreasing the power intensity from 300MW/m² to 18,75MW/m². The 99.9% Mirror used in the NIAC experiment had a threshold of 50MW/cm².
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Post by Enderminion on Jun 23, 2017 13:12:04 GMT
300Mw to 1,875Mw totally decreasing, also if its not 100% efficent then laser energy will leak and heat the mirrior, reducing it's efficiency letting more energy into the mirrior, which leads to the sail suffering sudden destrction in a way not dissimiler to an inbound warhead getting lased
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Post by Kerr on Jun 23, 2017 13:42:53 GMT
300Mw to 1,875Mw totally decreasing, also if its not 100% efficent then laser energy will leak and heat the mirrior, reducing it's efficiency letting more energy into the mirrior, which leads to the sail suffering sudden destrction in a way not dissimiler to an inbound warhead getting lased 300MW to 19MW. Sorry my bad, I used the pumping wattage instead of the total beam power. From 4.2MW/m² Heat (3000K) to 4.2GW/m² heat.
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