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Post by midnightdreary on Jan 8, 2017 8:34:06 GMT
I hope we stay with existing tech... We can "what if" science fiction arguments all day. <snip>... "be useless for hitting anything aside from the broad side of a planet". Which, I think, is the perfect use for a relativistic kill missile. Hard to move a planet out of the way, so it might be fine to take years.
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Post by caiaphas on Jan 8, 2017 8:41:40 GMT
<snip>... "be useless for hitting anything aside from the broad side of a planet". Which, I think, is the perfect use for a relativistic kill missile. Hard to move a planet out of the way, so it might be fine to take years. Yes, but when you're dealing with that kind of timeframe and have a gigantic glowy multi-gigawatt target in the sky, it's also trivially easy to observe its path, figure out where it's going to be, and destroy it. Armor it? Well now you have an even longer timeframe, because your acceleration's gone down proportionally. Add more engines? You need more reactors to power it and more radiators to get rid of the waste heat, making it even more noticeable and making it a lot easier to target and cripple it. Also, please note that we're not talking about Killing Star 0.97cee relativistic KKVs capable of turning whole cities to ash (and even then they launched a sustained bombardment), we're talking about a piddling 0.01cee. At that point it'd be far more practical to sink the money into many, many nukes.
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Post by The Astronomer on Jan 8, 2017 8:55:11 GMT
RKKVs. They are launched from one star system, and impact a planet in another system.
My new proposal is to launch a lot of random mass at it to maybe at least slow them down.
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Post by thorneel on Jan 8, 2017 12:16:16 GMT
One existing (if immature) technology that is not modelled in CDE is laser launch. With those giant death beams and monster generators, it should be enough to propel a laser sail at low relativistic speed.
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Post by bigbombr on Jan 8, 2017 13:09:14 GMT
One existing (if immature) technology that is not modelled in CDE is laser launch. With those giant death beams and monster generators, it should be enough to propel a laser sail at low relativistic speed. True, but with a laser like that at your disposal, a lasernet makes much more sense (more energy efficient, much more scalable in terms of force, less time to target, ...). toughsf.blogspot.com/2016/04/lww-laser-weapon-web.html
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Post by The Astronomer on Jan 8, 2017 13:14:14 GMT
One existing (if immature) technology that is not modelled in CDE is laser launch. With those giant death beams and monster generators, it should be enough to propel a laser sail at low relativistic speed. Two uses: zap projectiles and launching tiny laser sails.
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Post by newageofpower on Jan 8, 2017 22:44:33 GMT
One existing (if immature) technology that is not modelled in CDE is laser launch. With those giant death beams and monster generators, it should be enough to propel a laser sail at low relativistic speed. The problem with laser sail arrangements for transportation (not such a huge problem in warfare) lies in deceleration. Sure, with petawatts of laser energy it might be possible to boost a colony ship past .5C, but how will it slow down on the other end?
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Post by thorneel on Jan 8, 2017 23:15:26 GMT
One existing (if immature) technology that is not modelled in CDE is laser launch. With those giant death beams and monster generators, it should be enough to propel a laser sail at low relativistic speed. The problem with laser sail arrangements for transportation (not such a huge problem in warfare) lies in deceleration. Sure, with petawatts of laser energy it might be possible to boost a colony ship past .5C, but how will it slow down on the other end? A suggestion was to drop part of the sail and use it as a reflector to beam the laser back. The dropped sail continues to accelerate, but the colony ship decelerates. It is at best half as efficient as direct beaming, though. I guess the final stage can also use the star itself on solar sail mode, if there is a suitable one at destination (so no brown dwarves).
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Post by The Astronomer on Jan 9, 2017 11:02:44 GMT
The problem with laser sail arrangements for transportation (not such a huge problem in warfare) lies in deceleration. Sure, with petawatts of laser energy it might be possible to boost a colony ship past .5C, but how will it slow down on the other end? A suggestion was to drop part of the sail and use it as a reflector to beam the laser back. The dropped sail continues to accelerate, but the colony ship decelerates. It is at best half as efficient as direct beaming, though. I guess the final stage can also use the star itself on solar sail mode, if there is a suitable one at destination (so no brown dwarves). Magnetic sails work as well, and probably better.
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Post by bigbombr on Jan 9, 2017 14:26:25 GMT
One existing (if immature) technology that is not modelled in CDE is laser launch. With those giant death beams and monster generators, it should be enough to propel a laser sail at low relativistic speed. The problem with laser sail arrangements for transportation (not such a huge problem in warfare) lies in deceleration. Sure, with petawatts of laser energy it might be possible to boost a colony ship past .5C, but how will it slow down on the other end? Using the laser sail to get up to speed, flipping around and using solar light to slow down at arrival with assistance op rocket engines (ion drives, the laser can be used to beam the power) seems like the most optimal way to do interstellar travel. The more delta-v is taken care of by the solar sail/laser sail, the less delta-v you need in terms of propellant.
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Post by The Astronomer on Jan 9, 2017 14:30:10 GMT
The problem with laser sail arrangements for transportation (not such a huge problem in warfare) lies in deceleration. Sure, with petawatts of laser energy it might be possible to boost a colony ship past .5C, but how will it slow down on the other end? Using the laser sail to get up to speed, flipping around and using solar light to slow down at arrival with assistance op rocket engines (ion drives, the laser can be used to beam the power) seems like the most optimal way to do interstellar travel. The more delta-v is taken care of by the solar sail/laser sail, the less delta-v you need in terms of propellant. I have a feeling that solar sail might not be sufficient for deceleration upon arriving in a new star system.
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Post by bigbombr on Jan 9, 2017 14:43:22 GMT
Using the laser sail to get up to speed, flipping around and using solar light to slow down at arrival with assistance op rocket engines (ion drives, the laser can be used to beam the power) seems like the most optimal way to do interstellar travel. The more delta-v is taken care of by the solar sail/laser sail, the less delta-v you need in terms of propellant. I have a feeling that solar sail might not be sufficient for deceleration upon arriving in a new star system. I fully agree, but you're carrying that sail around for your acceleration fase, might as well use it. It would be grossly insufficient on it's own, which is why I stated it would probably be combined with an ion drive or something similar (power can be beamed by that massive laser you used for your acceleration fase).
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Post by bigbombr on Jan 9, 2017 14:46:59 GMT
One existing (if immature) technology that is not modelled in CDE is laser launch. With those giant death beams and monster generators, it should be enough to propel a laser sail at low relativistic speed. The problem with laser sail arrangements for transportation (not such a huge problem in warfare) lies in deceleration. Sure, with petawatts of laser energy it might be possible to boost a colony ship past .5C, but how will it slow down on the other end? Laser launch in atmosphere is more like a laser-powered pulse-jet (at high speeds probably transitioning to a laser-powered (sc)ramjet) than a solar sail. For celestial bodies with a dense(-ish) atmosphere, it's probably more efficient than a mass driver. Much more pleasant to ride, too.
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Post by The Astronomer on Jan 9, 2017 15:12:47 GMT
I have a feeling that solar sail might not be sufficient for deceleration upon arriving in a new star system. I fully agree, but you're carrying that sail around for your acceleration fase, might as well use it. It would be grossly insufficient on it's own, which is why I stated it would probably be combined with an ion drive or something similar (power can be beamed by that massive laser you used for your acceleration fase). I thought I've already mentioned the magnetic sail...
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Post by bigbombr on Jan 9, 2017 15:23:53 GMT
I fully agree, but you're carrying that sail around for your acceleration fase, might as well use it. It would be grossly insufficient on it's own, which is why I stated it would probably be combined with an ion drive or something similar (power can be beamed by that massive laser you used for your acceleration fase). I thought I've already mentioned the magnetic sail... True, a magnetic sail is much more potent, but you're already carrying a photon sail for your acceleration 'burn', an additional sail would increase the weight and cost of your craft. Is the magsail powerful enough? How does it compare to a MPD drive? It might be a better pick than an MPD drive, if it is sufficiently powerful.
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