tag:blogger.com,1999:blog-8150340806781551727.post1919811942350276240..comments2024-03-29T07:43:40.648+00:00Comments on ToughSF: Inter-Orbital Kinetic Energy Exchanges: Part IMatter Beamhttp://www.blogger.com/profile/16721504049578296529noreply@blogger.comBlogger48125tag:blogger.com,1999:blog-8150340806781551727.post-45832741158863338762018-11-27T01:01:22.076+00:002018-11-27T01:01:22.076+00:00Yes! Sorry for the long delay. I think I've go...Yes! Sorry for the long delay. I think I've got something big coming within this week.Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-49949726246178550792018-11-25T22:07:08.831+00:002018-11-25T22:07:08.831+00:00Any plans for new articles here soon? Great work.Any plans for new articles here soon? Great work.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-22117502364258319162018-09-14T23:13:33.333+01:002018-09-14T23:13:33.333+01:00In principle, you could do this with a really mass...In principle, you could do this with a really massive set of rubber bands, all the is really required is a way to provide an impulse to the mass to get it into a transfer orbit, and a way to capture the mass and retrieve the energy. As a practical matter a massive rotating tether is great for flinging payloads and capturing them, but extracting "excess" energy is a bit of a chore.<br /><br />In real life, the tether is going to either gain or lose rotational energy (based on "flinging" or "capturing"), and can also express the energy by gaining or losing orbital altitude. As well, I suspect a lot of energy will be wasted by flexing and vibrations along the tether.<br /><br />Coilguns or mass drivers will have issues as well, but the major advantage is their energy can be fed or tapped as electricity, which is much more fungible. You can quickly take the electrical energy from an Earth orbiting mass catcher and use it to perform industrial work in orbital facilities, split water into H2 and O2, or charge up millions of Tesla cars. The mss drivers can be fed from fusion reactors, giant solar panels or other external sources of energy as well. Rotating tethers will likely need rocket engines to start the rotational process. with the issues that might cause.<br /><br />The final issue is where these devices will be placed. A mass driver can be on the surface of a moon or asteroid, as well as flying in orbit or deep space, while a tether will have to be in orbit or deep space, and if in orbit, in a high enough orbit to clear other structures and prevent orbital decay from causing it to crash to the surface (should there be a long delay in receiving incoming packages and gaining energy, for example).<br /><br />So in general, I would be more inclined to go for mass drivers or coilguns over rotating tethers.Thucydideshttps://www.blogger.com/profile/09828932214842106266noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-72130792000644182018-09-09T07:26:08.694+01:002018-09-09T07:26:08.694+01:00Can we do this with rotating tethers instead of co...Can we do this with rotating tethers instead of coilguns?Law Wonghttps://www.blogger.com/profile/16627278931006086881noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-76407360319645041072018-09-02T23:58:30.434+01:002018-09-02T23:58:30.434+01:00Soon! I am trying to find time to complete and pos...Soon! I am trying to find time to complete and post a few things. Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-39984794068950320392018-09-02T21:55:43.492+01:002018-09-02T21:55:43.492+01:00Any plans for new articles on this blog soon, real...Any plans for new articles on this blog soon, really liking what I've read so far.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-12398157304385477752018-08-22T21:13:56.465+01:002018-08-22T21:13:56.465+01:00Simple financial incentives would give sufficient ...Simple financial incentives would give sufficient justification to speeding up the delay between setting up a 'pipeline' and receiving the goods at the other end. You have the time value of money, the compounding required rates of return and other time-sensitive factors that make you want to recover your investment as quickly as possible. Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-68727433943081238512018-08-22T20:03:25.481+01:002018-08-22T20:03:25.481+01:00Much of that really depends on the economics of th...Much of that really depends on the economics of the system, and to a lesser extent, the political situation.<br /><br />Once you start sending a steady stream of mass "downhill", you are essentially filling a pipeline. Once the pipeline is "full", then you can continue to run things with minimal input or fuss. I would think that if you need to reduce the set up delay, there is either some economic or political emergency which requires you to eat the extra costs, but then you would want to gradually reduce and eventually eliminate "boosting" payloads downhill to get an equitable cost structure.Thucydideshttps://www.blogger.com/profile/09828932214842106266noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-76081983073699783752018-08-19T01:59:01.871+01:002018-08-19T01:59:01.871+01:00We're still working that out, but there's ...We're still working that out, but there's one obvious benefit to accelerating 'down' the gravity well: the travel times will be shorter. Most of the payload's time is spent slowly accelerating inwards from the Outer Solar System. A small kick to a higher initial velocity can drastically reduce the travel time and the 'set up delay' for any kinetic energy stream. Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-2308638329417365222018-08-18T22:21:00.371+01:002018-08-18T22:21:00.371+01:00Always glad to help. Personally I would focus more...Always glad to help. Personally I would focus more on using the high efficiency drives to go "uphill" and let the gravity well do al the work on the downhill leg. All you would need is a drive with sufficient power to make fine corrections as you fall to hit the mass catcher, and everything else is a net positive.<br /><br />I'm not clear if you would recover *more* energy than you would input using a drive on the downhill leg (the Laws of Thermodynamics and Conservation of Energy would suggest that the extra energy input in accelerating downhill is not going to be fully recovered at the mass catcher).Thucydideshttps://www.blogger.com/profile/09828932214842106266noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-8799961821969501442018-08-18T20:03:23.075+01:002018-08-18T20:03:23.075+01:00Zerraspace and I are actually going through the be...Zerraspace and I are actually going through the benefits of using high-efficiency propulsion schemes on the falling payloads to significantly boost the energy in to energy out ratio.<br /><br />Thanks for the link!Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-68170584366571335302018-08-17T03:44:49.877+01:002018-08-17T03:44:49.877+01:00A bit more on electric sails. While the KE exchang...A bit more on electric sails. While the KE exchange revolves around dropping down the gravity well, a sail such as described here can be used both to control the descent (especially the fine aiming at the end to hit the mass catcher) and of course to go "uphill" against the gravity well: https://arxiv.org/pdf/1808.02019.pdf<br /><br />IF you don't have a handy mass driver in the orbit of Uranus, you could always use the sail to "kill" your orbital velocity relative to the Sun and then start your fall towards Luna or wherever your target mass catcher happens to be.Thucydideshttps://www.blogger.com/profile/09828932214842106266noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-35979042554833607362018-07-23T02:38:59.991+01:002018-07-23T02:38:59.991+01:00Thucydides: A quasi-religious motive might end up ...Thucydides: A quasi-religious motive might end up being the case, but it is irrational and hard to discuss objectively. <br /><br />Bubble atmospheres, where sea-level conditions of 1 atm are maintained inside enclosed volumes, is not a very far fetched idea!<br /><br />Law Wong: 100% correct. Building an atmosphere on Mars needs input from external sources on the order of 10e18 to 10e22 kg. Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-41920575021926091152018-07-20T04:45:27.308+01:002018-07-20T04:45:27.308+01:00I suppose, as suggested above, you could electroly...I suppose, as suggested above, you could electrolyse enormous amounts of silicate sand and water to obtain 0.2 bar of oxygen atmosphere, but building the self-replicating factories to do that (on boggy terrain no less), and permanently sequestering the pure-ish silicon bars (or blasting it into orbit) is going to be a hassle. Are there plausible thermochemical methods? Law Wonghttps://www.blogger.com/profile/16627278931006086881noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-1828323807573647962018-07-20T04:36:10.139+01:002018-07-20T04:36:10.139+01:00Some popular theories indicate that most of Mars&#...Some popular theories indicate that most of Mars's carbon dioxide was lost to space (due to UV radiation and the solar wind) in the early stages of its history. <br />As a result:<br />The problem to me does not seem to be a lack of water, or oxygen (breathing masks are acceptable to most people).<br />The problem seems to be a lack of carbon dioxide (this was assumed by many of the early terraforming theorists to be in abundance). Even if you build seventy million square kilometers of foil mirror to char-grill Mars and boil the ice caps with giant terawatt lasers and asteroid strikes, you only end up with less than 0.1 atmospheres (0.1 bar) of pressure or something like that. Add in the dry ice in the deeply buried permafrost - that'll take decades or centuries to heat up and maybe you can squeeze out half an atm (0.5 bar).<br />Nitrogen is also a problem, as most people have noted.<br />Water, on the other hand, seems to be in abundance everywhere under the permafrost and in the ice caps, although sea level may be disappointingly low, leaving most of Mars a desert. <br />I'm also dreaming about positive/negative feedback effects and the effects of a terraforming project on existing settlements. In short, you do not want to live in a planetary construction site.<br />A good model might be terrestrial arctic settlements built on melting permafrost. Sinkholes, bogs, and landslides might be a problem (I have no idea how wet inorganic sand/clay behaves). <br />If too much water vapor saturates the atmosphere, we may end up with too much cloud cover, raising albedo and requiring even more mirror to heat Mars up. <br />That same water vapor might alternatively create a strong greenhouse effect (think Venus). This might be desirable for steam-cooking Mars to get all the volatiles out of the permafrost (but see above point, I do not know how to model this). The mirrors can be turned off once Mars is well-done. Law Wonghttps://www.blogger.com/profile/16627278931006086881noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-37040088331518271392018-07-20T02:23:52.504+01:002018-07-20T02:23:52.504+01:00I mostly agree with you WRT the difficulty of main...I mostly agree with you WRT the difficulty of maintaining a warm environment on Mars, but suspect that the motivations of the terraformers would be more akin to a religion than a technological project with a defined cost/benefit ratio. The people building the pyramids and other monumental architecture in ancient Egypt were skilled craftsmen and labourers who were evidently happy to build these things, even if a rational calculation would suggest building granaries and housing would be a far more effective use of their time. Builders of medieval cathedrals had similar impulses, embarking on projects which would take generations to complete.<br /><br />Of course in an SFnal setting, we can always apply various forms of handwavium to the problem (even if this isn't the purpose of your blog), including extended lifespans so people are willing to embark on 1000 year projects, artificial magnetic fields to protect Mars (a good use of the orbital kinetic energy) and even postulating an artificial diamond "shell" over the atmosphere to keep everything inside.Thucydideshttps://www.blogger.com/profile/09828932214842106266noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-79475248197431216582018-07-20T00:30:30.539+01:002018-07-20T00:30:30.539+01:00Interesting points. Catching cometary material de-...Interesting points. Catching cometary material de-orbited from the outer solar system, or ice launched from a moon, allows for vast amounts of energy to be gained. That energy can be applied to crack oxygen out of Martian rocks at a low cost and release the waste heat into the environment in a controlled manner, allowing you to deal with several problems at once. <br /><br />Even if we sublimated all of the frozen CO2 and melted all of the ice, we'd be left with a thin and toxic atmosphere, hence the need for the oxygen-releasing steps. Nitrogen is only about 5 times less abundant than oxygen in our Solar System, so getting a hold of it should not be difficult either. <br /><br />My issue with terraforming Mars is that the process is only worthwhile if you expect Mars to hold a very large population for a very long time, but whatever you do, Mars naturally wants to lose its atmosphere and return to its cold and dry state. It will have to be artificially managed to remain habitable, at which point it is not much better than artificial habitats. Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-22967782871669054722018-07-19T22:32:58.320+01:002018-07-19T22:32:58.320+01:00I enjoy reading speculations about terraforming Ma...I enjoy reading speculations about terraforming Mars. Much like many magic tricks, most serious proposals usually can be summarized with "it's done with mirrors".<br /><br />Using the mirrors to focus gigantic amounts of solar energy on points not eh Martian surface could conceivably bill the oxygen out of the Martian rocks (which is probably the most energy intensive option possible). Using less energy could sublimate the CO2 in the Martian polar caps, thickening the atmosphere to the point that you could have liquid water on the surface. The water itself can be melted out of the remaining polar ice and from Martian permafrost, the issue here is there is no clear understanding of just how much water there actually is (estimates of Martian permafrost and trapped water are all over the place). <br /><br />Sending some comets to bring more water to the surface seems to be a pretty obvious step, although unlike Law Wong's posts above, I would not want the comets to arrive at interplanetary velocity, since the energy of the impact is likely to blow more material back into space than you receive. Slowing them down via solar sail or other sail technology, or capturing cometary material in a decelerator to gather the kinetic energy, then dropping them at mere orbital velocity seems to be a much safer and more controllable option.<br /><br />Sending cometary material to a mass catcher or other kinetic energy gathering device seems to be the best solution, you get both your water and other elements to create an atmosphere and fill the Boreal Ocean, and you get a supply of energy to power the industrial economy of Mars (or at least the part in orbit). And the captured materials are equally useful in space as on the planet, one possible "sub plot" for anyone contemplating worldbuilding on these lines is how to deal with the economic, social and political pressures to send materials to one or the other destination. IF Space industry can reliably outbid the Terraforming effort, but Teraforming is the centrepiece of the Martian Government's platform, we can see lots of rent seekers and political operatives struggling for control, making for an interesting setting.Thucydideshttps://www.blogger.com/profile/09828932214842106266noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-65173350077524864782018-07-09T23:58:07.842+01:002018-07-09T23:58:07.842+01:00Construction projects are best served by sourcing ...Construction projects are best served by sourcing materials locally (from Mars's metal-rich surface) or from low-deltaV-cost sources (such as metallic asteroids). Sending materials all the way from the outer solar system does not seem reasonable.<br /><br />Nitrogen in the form of ammonia ice is plentiful. Comets are full of ices, and many can redirected at low cost to hit Mars, especially if the water ice on those same comets is used as propellant. Only if you're looking to fill up an entire planet's atmosphere with nitrogen do the comets start seeming insufficient. <br /><br />Mars only really needs enough sunlight to keep liquid water from freezing. No amount of sunlight will allow this while the atmospheric pressure is where it is. It is therefore necessary to increase the pressure to the point where the existing insolation can keep it liquid. For example, 10kPa and 10°C.<br /><br />Liquid water is great because it absorbs most of sunlight's energy and converts it into heat. Ice is bad because it reflects away sunlight. Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-21184706149138390212018-07-09T12:01:06.768+01:002018-07-09T12:01:06.768+01:00This blog is nice and very informative. I like thi...This blog is nice and very informative. I like this <a href="https://tophostingtm.com/review-177-inter-velocity.html" rel="nofollow"> blog</a>. <br /><a href="https://free-lancer.in" rel="nofollow"> blog</a> Please keep it up.<br /><br />Anonymoushttps://www.blogger.com/profile/06865571311603343899noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-33860368391788603942018-07-09T05:09:46.720+01:002018-07-09T05:09:46.720+01:00For comparison, the world produces 1.6 billion ton...For comparison, the world produces 1.6 billion tonnes of steel per year. Law Wonghttps://www.blogger.com/profile/16627278931006086881noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-65352089040038151552018-07-09T04:56:24.621+01:002018-07-09T04:56:24.621+01:00The mirror is, of course, a constellation of small...The mirror is, of course, a constellation of smaller, much more manageable mirrors. Law Wonghttps://www.blogger.com/profile/16627278931006086881noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-84128251709353998962018-07-09T04:52:24.263+01:002018-07-09T04:52:24.263+01:00Oh, I wasn't thinking of actually moving Mars....Oh, I wasn't thinking of actually moving Mars. More like building seventy million square kilometers of foil mirror (keeping 'em flat is going to be non-trivial) and sticking it at the Mars-Sun L2 point to light up Mars's nightside. <br />With Mars's surface area being 144 million square kilometers, this should be adequate to double insolation and achieve nicer temperatures. <br />At 1 gram per square meter (easily achievable with solar sails), all you need is seventy million tonnes of material - non-trivial, but much less than the mass of Deimos. <br />The point appears to be that Mars will not automatically become earth-like if we shine enough energy on it. And shipping trillions of tonnes of nitrogen (or more) in from the Outer System may well be much harder (methinks) than building seventy million square kilometers of foil mirror. Law Wonghttps://www.blogger.com/profile/16627278931006086881noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-39954361169929609462018-07-08T21:34:19.011+01:002018-07-08T21:34:19.011+01:00Correct, terraforming hasn't been discussed in...Correct, terraforming hasn't been discussed in ToughSF, because I generally take it to require technologies too advanced to speculate accurately on. Moving planets is even more far fetched!<br /><br />If we could move plants, bringing a watery moon such as Enceladus closer to the Sun is much more interesting. Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.comtag:blogger.com,1999:blog-8150340806781551727.post-57606349433530860992018-07-08T20:17:37.151+01:002018-07-08T20:17:37.151+01:00Hi!
You are correct. The projectile is simply the...Hi!<br /><br />You are correct. The projectile is simply the vessel through which gravitational potential energy is taken from the launcher's planet and added to the receiver's plant. <br /><br />The payload is launched by a coilgun. At the 'catcher' station, it is intercepted by a 'reverse coilgun', that applies electromagnetic braking to slow down the projectile to a stop while extracting its kinetic energy in the form of electricity. <br /><br />You won't need a terajoule storage system if you divide your payload into a stream of small projectiles. <br /><br />The catcher station does lose momentum and orbital velocity as it catches projectiles. It can spend a small percentage of the energy is receives to accelerate some propellant to compensate for this, and the propellant can come from an orbital propellant depot, a captured comet or scooped up from the atmosphere. Matter Beamhttps://www.blogger.com/profile/16721504049578296529noreply@blogger.com