tag:blogger.com,1999:blog-8150340806781551727.post119305058925943073..comments2024-03-29T07:43:40.648+00:00Comments on ToughSF: The Laser Problem IIMatter Beamhttp://www.blogger.com/profile/16721504049578296529noreply@blogger.comBlogger13125tag:blogger.com,1999:blog-8150340806781551727.post-47848688544617127732021-01-16T05:09:59.714+00:002021-01-16T05:09:59.714+00:00Oh, those are certainly just example figures to he...Oh, those are certainly just example figures to help the demonstration. Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-31945583592935580622021-01-10T23:08:39.054+00:002021-01-10T23:08:39.054+00:00I think I understand how most you get most of the ...I think I understand how most you get most of the numbers, but...<br /><br />How do you get the electric power conversion rate and laser efficiency? Is that mostly up to the author, who decides based on the technology at hand, or are there equations for them?Anonymoushttps://www.blogger.com/profile/06214868476274904946noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-44303780594548901742020-03-27T04:32:38.961+00:002020-03-27T04:32:38.961+00:00I don't really agree with the "Lasers pus...I don't really agree with the "Lasers push combat ranges to such extremes, that they make spacecraft with any level of acceleration seem immobile over the course of the engagement." , the further away the opponent is in a laser fight the more likely it is that it's maneuvering will have a material effect on it getting hit. The probability of a laser hitting can be taken down to , <br /> Number of shots to hit a given size = Pi x 0.25 x a^2 x 16d^4 x c^-4, where laser diameter is greater then the area to be hit d^4 reduces to d^2.<br />Where a is acceleration of the targeted craft, and d is engagement distance. Depending on exactly how far away lasers can reach, and how crafts cross sectional area scales with weapon ranges, the decisions made can dramatically effect outcomes. <br />FreakingSharkswithFreakingLazerBeamshttps://www.blogger.com/profile/01343769469112812795noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-87048023981440267732019-02-09T20:50:33.423+00:002019-02-09T20:50:33.423+00:00The problem with that 'charge up time' is ...The problem with that 'charge up time' is that pulsed lasers usually have pulses of a handful joules, which take milliseconds to charge up. They work by sending thousands of those pulses per second, in a stream. <br /><br />A femtosecond laser firing pulses of 1 Joule each would have a peak power of 1 TeraWatt. If it is being given 1 MW of energy, then it would fire 1 million pulses per second, with 0.999999 microseconds in between the pulses. <br /><br />Unlike in Star Trek, there is no way to detect a 'build up of energy' inside an enemy ship. But, there are thermal constraints on the lasers. Perhaps you could have a battle where overloading your lasers gives you a short term advantage, but forces you to stop shooting after a while to let the laser cool off? And if you continue overloading for too long, the laser is damaged and eventually melts?Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-49874041804660316712019-02-06T20:05:38.802+00:002019-02-06T20:05:38.802+00:00What if we include some charge up/cooldown time in...What if we include some charge up/cooldown time in a femtosecond laser blast.Lasers requires lot of power and also generate a lot of heat so adding capacators and heat sinks are a welcome choice . Then the combact might revolve between bating your enemy to use his countermesures and landing a mulmultiple hits while wour enemy was not ready. This could make the combact intresting. So what could be the countermeasures if your sensors can detect the buldup and relese of energy. Also what type of heat sinks and readiators can take such loadsThe Librarianhttps://www.blogger.com/profile/01646848861149556379noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-87366718681226600662016-07-15T10:14:56.111+01:002016-07-15T10:14:56.111+01:00Another point to address is your description of &q...Another point to address is your description of "ravenous beams of instant death". Even accepting that the laser will penatrate any defense at relatively close ranges, this does not necessarily constitue "instant death". There is a misconception that if a laser penetrates a target, the target dies. In much the same way that a human can often sustain several hits from a 9 mmm gun, without being slowed down very much (especially if under the influence of strong drugs), the same feature that allows a laser to drill through armour plate will reduce the likelihood of the beam actually resulting in a good kill. This is usually refered to as "lack of stopping power". 9 mm guns are often very powerful, and specially tipped bullets allow them to penetrate most wearable armour... but they often just pass straight through the body, often without doing any significant damange to tissue. You bleed, but unless you hit a vital organ you don't stop an attacker, and one can live for several hours before the actual bleeding becomes life threatening. Same for a laser. If you have a vessel that is properly laid out, it will take dozens (and perhaps even hundreds) of penetrations before the vessel loses its ability to fight. Anonymoushttps://www.blogger.com/profile/08104586551355707368noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-32599555886557577742016-03-21T00:06:00.573+00:002016-03-21T00:06:00.573+00:00A rocketpunk scenario of 1950's tech IN SPACE ...A rocketpunk scenario of 1950's tech IN SPACE with vacuum tube electronics and gunners plotting firing solutions with slide rules?Lukehttps://www.blogger.com/profile/09617890536562434320noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-46082856287025016472016-03-20T05:14:12.956+00:002016-03-20T05:14:12.956+00:00That's a bit of a downer...
Let me appeal fro...That's a bit of a downer...<br /><br />Let me appeal from another direction: what factors could plausibly reduce the acuracy of a laser weapon in vacuum?Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-23221791365576990412016-03-20T03:33:04.601+00:002016-03-20T03:33:04.601+00:00It is useful to think of a laser as an inverse tel...It is useful to think of a laser as an inverse telescope. Since light takes the same route coming as going, if you trace the light rays from a spaceship, say, that you are observing with a telescope to your light collecting sensor in the scope, then if you replace the sensor with a beam emitter, the beam will follow that same path back.<br /><br />This is useful because we have a number of examples of very large telescopes that are limited only by the diffraction of light. That is, the pointing error of the beam axis is much less than the diffraction limited resolution of the scope. Reversing this, the same scope shooting a laser would have a pointing error less than the diffraction limited spot size at the target. This means that for practical purposes, inaccuracy of the beam can be neglected. The main limit is that beyond a certain range, the beam spot size is too large to do much damage (while at the same time the resolving power of your optics isn't good enough to figure out what are the best parts to shoot at, for the same reason).<br /><br />Of course, this is all for visible light lasers and longer wavelengths. For x-ray telescopes, you still get a pointing accuracy better than the resolution, but we don't know how to get diffraction-limited resolution from an x-ray telescope yet and if we did, the instantaneous resolution might be less than the pointing error (which would of course reduce the resolution for a scope, because the image would be jittering all over the sensor plane). So it might be possible that a super-duper x-ray laser might not have perfect aim (or maybe it would - engineers are very clever).Lukehttps://www.blogger.com/profile/09617890536562434320noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-91748151240713265152016-03-16T02:25:32.331+00:002016-03-16T02:25:32.331+00:00A common misconception. It will be discussed soon,...A common misconception. It will be discussed soon, but you just have to achieve stealth in different ways. <br /><br />Also, lasers in space are not extremely accurate at long range because they are physical constructs that have to be immobilized without solid ground to push against. In fact, they'll use many of the vibration-reducing technologies employed by submarines today. <br /><br />Just imagine the mass of a 10m diameter dielectric mirror, and how much momentum it generates trying to change target, How would you suppress that quickly without making the beam wobble? How do you react to the mirror heating up slowly and changing shape? How do you deal with random impacts of micro- and macro-projectiles on your ship and on the mirror itself?<br /><br />It's never a perfect world. Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-50826325561975526792016-03-14T16:38:36.470+00:002016-03-14T16:38:36.470+00:00@Hal Effect
In space, there simply *is* no stealth...@Hal Effect<br />In space, there simply *is* no stealth. <br />http://www.projectrho.com/public_html/rocket/spacewardetect.php#id--There_Ain%27t_No_Stealth_In_Space<br /><br />The only way to make lasers miss (assuming their tracking is accurate enough) is to be so far away from the emitter that lightspeed lag allows you to be elsewhere - preferably where the enemy did not predict you would be.<br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-75150768031061457872016-03-02T19:31:00.621+00:002016-03-02T19:31:00.621+00:00I will discuss solutions to the Laser Problem in t...I will discuss solutions to the Laser Problem in the third post, but even if stealth tech reduces the long-range effectiveness of lasersm they would do nothing against the fact that they become ravenous beams of instant death at short range. <br /><br />Also, combat would likely take place BEFORE the attackers have started de-accelerating into an orbit around the objective. This would give the defenders the upper hand, by creating two 'win' conditions: destroy the opponents, or stop them from de-accelerating into orbit. <br /><br />In the first case, there's no-one left to worry about. In the second case, they'll be flung out into outer space and you won't have to worry about them again for months or years. <br /><br />The point is, stations and planets will be defended from millions of km away.Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-66439919288290739492016-03-02T14:28:45.197+00:002016-03-02T14:28:45.197+00:00Interesting, but what if there is stealth tech, an...Interesting, but what if there is stealth tech, and one cannot see the opponent until a certain distance. this means that combat would be concentrated around valuable areas, (stations and planets) and long range laser-fire would not be nearly as effective.Anonymoushttps://www.blogger.com/profile/11463805796271201742noreply@blogger.com