tag:blogger.com,1999:blog-8150340806781551727.post3530854742488812683..comments2024-03-29T07:43:40.648+00:00Comments on ToughSF: Permanent and Perfect Stealth in SpaceMatter Beamhttp://www.blogger.com/profile/16721504049578296529noreply@blogger.comBlogger88125tag:blogger.com,1999:blog-8150340806781551727.post-9012155547763881142024-03-17T08:45:35.038+00:002024-03-17T08:45:35.038+00:00The acceleration is very low, so the stresses on a...The acceleration is very low, so the stresses on a frame would be modest. Also, the tanks could be supported through internal pressure (balloon tanks). Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-353266586975157212024-02-18T00:58:47.399+00:002024-02-18T00:58:47.399+00:00I'm having a hard time envisioning the load-be...I'm having a hard time envisioning the load-bearing structural architecture of this ship, with multi-layered vaccuum-insulated hull, these wire-deploying mechanisms (along with tension-bearing trusses?), and long cryotanks all bent laterally by the engine at COM...David Perryhttps://www.blogger.com/profile/07628991184561866521noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-27952025260754603532023-12-09T09:02:26.341+00:002023-12-09T09:02:26.341+00:00Torch ships travel extremely fast, so the period o...Torch ships travel extremely fast, so the period of useful stealth is reduced from months to days. They propulsion systems also remain radioactive for a long time, especially the nozzle which sits right next to the deluge of neutrons from a fusion reaction. So it becomes to very hard to switch from travel mode to stealth mode. And, the gap between the deltaV/acceleration of a stealth ship and a torch ship becomes extremely wide.<br /><br />The comment about boiling neon and other cryogenic gases is based on the fact that despite absorbing less Joules per Kilogram when boiling off, they are also much denser. So you might be able to absorb more Joules per Cubic meter! That is important because the major source of heat that forces you to boil off a coolant in a steamer is sunlight touching the exposed front of the spaceship. Denser coolant means smaller spaceship which means less area exposed to sunlight, so you don't have to boil off as much in the first place... making the heat capacity decrease of switching from liquid hydrogen to liquid neon less of an issue...Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-53100917964539017102023-11-27T22:11:57.729+00:002023-11-27T22:11:57.729+00:00Hi matterbeam to drag you back to this article aga...Hi matterbeam to drag you back to this article again. I was just wondering about the last part of this comment. “The best use of stealth technology in a setting without torch ships” obviously raised the question to me, what to do with stealth ships of the steamer lineage in a torch ship setting. In particular stealthy propulsion of that caliber. I was also curious about your comments about more efficient/advanced heat pumps and how they would effect this system. Why would they remove the need for helium but not hydrogen? And your response to the comment about using neon and other elements to add capabilities to this design really intrigues me but I don’t think I understand it enough to ask anything coherent. Michaelnoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-33423956774565173772023-11-08T06:56:02.676+00:002023-11-08T06:56:02.676+00:00From the point of view of a stealth ship, this is ...From the point of view of a stealth ship, this is an acceptable cost as it would allow them to travel around the Solar System as quickly as any regular military ship. The size and mass penalties are of less consequence to a design that is not supposed to engage in direct combat or in tactical maneuvers in the first place. <br />For one I slightly disagree we could still have the nozzle built within the ship without it being exposed so that it could still be used in combat and such Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-24670919923877372452023-11-03T13:44:04.921+00:002023-11-03T13:44:04.921+00:00You're not sending out a single 'string...You're not sending out a single 'string' but sprouting billions of 'hairs'. I hope that analogy makes sense.Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-56211570218873103522023-10-30T23:07:41.784+00:002023-10-30T23:07:41.784+00:00Great post. While reading, I admit to being a bit ...Great post. While reading, I admit to being a bit skeptical about being able to deploy 23.16 billion kilometers of wire radiators... how would something like that be possible? Even if you were able to deploy 1000km of wire per second, (or 10 wires at 100 kps, or even 1000 wires at 1 kps), you would still need 8 months to deploy them all. What am I missing?Unknownhttps://www.blogger.com/profile/15074346576699873102noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-25944098464809004912023-10-30T23:06:53.721+00:002023-10-30T23:06:53.721+00:00Great post. While reading, I admit to being a bit ...Great post. While reading, I admit to being a bit skeptical about being able to deploy 23.16 billion kilometers of wire radiators... how would something like that be possible? Even if you were able to deploy 1000km of wire per second, (or 10 wires at 100 kps, or even 1000 wires at 1 kps), you would still need 8 months to deploy them all. What am I missing?Unknownhttps://www.blogger.com/profile/15074346576699873102noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-415828751699130642023-10-12T19:09:28.728+01:002023-10-12T19:09:28.728+01:00If you could do this you wouldn't need an NTR ...If you could do this you wouldn't need an NTR for very long!<br /><br />I now wonder about mixing this with a Q-Drive. Your coolant is your propellant for an electric rocket. Your windmill and a very efficient reactor like a PIDEC could ionize the gas if it's not yet hot enough and accelerate it without adding too much heat, but even then it might help. <br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-17972208810826642342023-10-12T06:15:48.732+01:002023-10-12T06:15:48.732+01:00Did anything come of this idea? 👀Did anything come of this idea? 👀Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-55468677853459500142023-09-11T18:31:49.258+01:002023-09-11T18:31:49.258+01:00If you treat everything as gas, that doesn't s...If you treat everything as gas, that doesn't seem too bad, granted you somehow get away with a gas core that doesn't need radiators! But the remass coming out of a gas core isn't a gas, it's a plasma, is it not? <br /><br />Interesting idea, I just wonder how you'd cool the plasma without losing speed before it became gas again.<br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-72684502131580748422023-09-10T23:59:16.434+01:002023-09-10T23:59:16.434+01:00If a solid-core nuclear rocket can deliver 1000s I...If a solid-core nuclear rocket can deliver 1000s Isp, then a gas-core nuclear rocket could reach 3000s or beyond.<br /><br />With a mass ratio of 10, that's enough for a deltaV of over 67 km/s. <br />Stealth ships pay for their ability to hide from sensors with reduced performance - less acceleration, lots of dead weight in the form of massive nozzles and so on.<br /><br />The nozzle throat could be hidden if the nozzle was curved in some way. The rest of it would have to be cooled by pumping liquid hydrogen through the walls and keeping the propellant flow rate very low. Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-43167637853191759522023-09-08T01:29:57.514+01:002023-09-08T01:29:57.514+01:00"Gas-core nuclear rockets, for example, can s..."Gas-core nuclear rockets, for example, can significantly increase the acceleration under stealth."<br /><br />To what degree? What kind of total dv can be had with this? Sure, a big nozzle helps, but that could potentially weigh a lot, and cooling the gas-core could be pretty hard too. And even if the nozzle wasn't heavy, wouldn't the nozzle at the narrow part be difficult to cool? Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-41614529149161342252023-06-07T21:28:38.374+01:002023-06-07T21:28:38.374+01:00Gases cool down when they expand; that's just ...Gases cool down when they expand; that's just the PV = nRT relationship. A large nozzle expands exhaust gases more, so the final exhaust stream gets colder. Even the 3000 Kelvin gases from a nuclear thermal rocket can be expanded to the point where they are below 20 Kelvin... you just need a nozzle with an expansion ratio of several tens of thousands (unlike the typical 1:200 of a vacuum nozzle today).Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-73955620710206449472023-06-07T16:27:43.703+01:002023-06-07T16:27:43.703+01:00I realize this is an old comment, but how do you h...I realize this is an old comment, but how do you have super expansion nozzles with nuclear drives?! I can't even see how that works with ion drives. <br /><br />The only options that come to mind for stealthy rockets that aren't super expansion gas thrusters would be nanoparticle/macron or maybe a neutral particle beam. Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-72702573012553199422023-03-30T17:15:52.354+01:002023-03-30T17:15:52.354+01:00That's an interesting idea. I'll look into...That's an interesting idea. I'll look into it!Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-88089549386395330362023-03-30T17:15:08.633+01:002023-03-30T17:15:08.633+01:00I don't have enough information to give you a ...I don't have enough information to give you a good answer. I know hydrogen doesn't simply freeze solid in the vacuum of space, especially with the Sun present. Also, rocket exhaust expands extremely quickly in vacuum, so even if it is somewhat hot, it becomes so optically thin that it simply doesn't get picked up by cameras. Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-9078244930166489902023-03-28T03:41:09.332+01:002023-03-28T03:41:09.332+01:00How can you be so sure the exhaust would be undete...How can you be so sure the exhaust would be undetectable? Sure it is extremely cold but it is hardly a thin gas the density and temperature of the interplanetary medium. We cannot assume the engine nozzles function as perfect mathematical models with zero turbulence, and excess cooling would lead to formation of extremely reflective crystalline ices in the exhaust. Having the engine running would be essentially like emitting a constant stream of chaff.<br />The exhaust must also be at least war enough to prevent the engine simply filling with ice to begin with. Exhaust moving at km/s striking any irregularity in the nozzle would heat up tremendously.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-5772757915908128422023-03-26T20:18:10.538+01:002023-03-26T20:18:10.538+01:00Hi MatterBeam,
Your laser ablative design, with t...Hi MatterBeam,<br /><br />Your laser ablative design, with the graphite/carbon shell around a low molar mass gas, is certainly a pulse propulsion design, right? The engine nozzle might be gargantuan depending on power level, but wouldn't that potentially give you some serious legs while staying stealthy? <br /><br />I can also seeing this used for beam-power drones, depending on how well lasers scale down and how ridiculous a tiny drone on top of a huge engine nozzle looks. Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-17713238702661866172021-07-01T20:15:31.634+01:002021-07-01T20:15:31.634+01:00Your post doesn’t include considerations for quant...Your post doesn’t include considerations for quantum radar, laser searching, metamaterial stealth, RAM heating up or fiber radiator efficiency reductions from radiated heat hitting other fibers.<br /><br />>Typical sensors have very small fields of view.<br /><br />That’s not exactly typical of military sensors.<br /><br />>Longer wavelengths as long as 10 or 100m long can diffract around the spacecraft without interacting with it.<br /><br />Radar wavelengths are still liable to reflect off larger surfaces and a surface can resonate with wavelengths 1/10 to 1/1 it’s size. <br /><br />>the rest of the body cylindrical<br /><br />Radar waves tend to bend around circular objects that are 10/1 to 1/1 their size and produce creeping waves that emit circularly in all directions. It’s why stealth aircraft/munitions avoid circular nose cones. Making your stealth ship cylindrical is probably a horrible idea. <br /><br />>We will consider the detection distance of the ATOMSS example design against a small telescope (2m wide collector area), a large telescope (10m wide collector area) and a huge 100MW radio telescope (20m wide dish). <br /><br />I don’t think those dish sizes seem appropriate. Firstly, there’s no size limits in space, so they seem pretty small. Secondly, the sensors are liable to use high speeds and inverse synthetic aperture techniques to “create larger dishes.” Thirdly, the enemy’s sensors would probably be operate together as a multi-static array and combine their results.<br /><br />>the front of the ATOMSS spaceship can be reproduced by a 4m wide sphere of graphite cooled by a small tank of liquid hydrogen. To an infrared sensor or a radio telescope, this is indistinguishable from the front of a stealth craft.<br /><br />It’d likely be distinguishable by omni-directional creeping waves and by ISAR.<br /><br />>a tiny emitter on the stealth ship to overpower or confuse a huge and powerful emitter on the radio telescope.<br /><br />That’s probably a bad idea. Modern radars can utilize narrow beams and frequency hopping. If you try to jam 1 you’re liable to give away your direction. If you try 2, the ship would be at the intersection of the beams. It may be better to disperse a field of decoy repeater jammers in front of the ship at ranges where enemy beams would overlap multiple jammers; however the radio telescopes could angle their beams to overlap behind the grid and only consider signals that returns those 2+ frequencies at the exact same time. Also, SAR/ISAR techniques could help. Standoff jamming from Mars might be more helpful.<br /><br />>a small number of lasers...can render any sensor looking at these wavelengths useless as the signals from the ATOMSS are drowned out by the signals from these lasers.<br /><br />Why assume a small number of sensors, that you know where they are, that the sensors can’t filter obvious sources of noise and that they can’t just use shades?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-749832735696299162021-05-09T18:11:54.393+01:002021-05-09T18:11:54.393+01:00This does indeed make a lot of sense. I'll loo...This does indeed make a lot of sense. I'll look into the physics behind this a bit more. Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-46205098624589039872021-04-28T10:56:53.433+01:002021-04-28T10:56:53.433+01:00I should add, to clarify: the reason why the energ...I should add, to clarify: the reason why the energy density of the cavity is increasing, is because the perpendicular polarised light is being reflected inside the cavity, by the mirrors, but cannot be reabsorbed. Since it is however still constantly being emitted by the wire radiator, it accumulates to arbitrarily high energy densities.Emil Mahnkenoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-85893606300009375442021-04-28T10:52:00.127+01:002021-04-28T10:52:00.127+01:00Hi Matter Beam, thank you for this fascinating art...Hi Matter Beam, thank you for this fascinating article, as always.<br />I have a remark regarding the wire radiators, which you may be able to clear up.<br />While I like the idea of avoiding reabsorption from nearby radiators by making them thin enough to not absorb perpendicularly polarised light, I am not convinced that this is something that will work:<br />The way I see this, is that it could lead to some sort of Maxwell's demon.<br />Introduce a single wire of infinite length and surround it by a perfectly reflective, cylindrical mirror (for the sake of argument).<br />According to your proposition, the wire will emit in all polarisations, but only reabsorb in the axis of the length of the wire. Here we have a scenario where the optical cavity formed by the mirror has a constantly increasing density of perpendicularly polarised light, as it cannot be absorbed. Hence the energy density of the cavity is increasing to arbitrary levels, without any work being done. This obviously violates thermodynamics: by introducing a small object into the cavity and linking the radiator to a source of heat, we can increase the temperature of the object to a higher temperature than that of the heat reservoir, without doing any work to run this heat pump.<br />My best guess as to what is happening, is that if the wire radiators are too thin to absorb in one polarisation, they will also not emit in that polarisation.<br /><br />Let me know what you think. Am I wrong in my thinking? It's entirely possible.<br /><br />E.M.Emil Mahnkenoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-52220232487150508682020-10-02T12:25:53.368+01:002020-10-02T12:25:53.368+01:00I was thinking as a initial concept, a combat read...I was thinking as a initial concept, a combat ready starship going to L2 lagrange point (because they would be very difficult to hit from earth) than dropping a mini-ATOMSS witch go to LEO in stealth mode and once near the target, it drop a few HGV (Hypersonic glider Vehicule) on ground target or some ASAT weapon on ennemy satellites.<br />The ennemy woudn't notice the attack probably until all targets are hit.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-51553179264183878612020-10-02T03:02:13.147+01:002020-10-02T03:02:13.147+01:00Thank you. Yes, that is possible. It would have to...Thank you. Yes, that is possible. It would have to be very lightweight though, because it is difficult to store a lot of hydrogen in the volume of the Starship's payload bay.Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.com