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radonek

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Posts posted by radonek

  1. On 11/20/2022 at 1:03 PM, magnemoe said:


    One major problem with asparagus fuel flow is that rocket engines has an very high fuel requirement, piping is more like an small hydro plant than even piping to huge ships, the turbo pumps also don't like gas bubbles and cavitation this makes switching between tanks is challenging unlike ships and planes who does this regularly. 

    What if you don't pipe that extra fuel directly into engine, but top-off center tank, using it as a buffer?

    One reason for using asparagus that I don't see mentioned is that it allows me to use beefier center engine. With center tank full, there is less of a TWR jump through staging, without need to throttle down. I know that bigger engine is not called for at LEO missions, but for heavier cargo at TLI or farther burns… 

     

  2. This is mostly fearmongering IMO. Any AV needs to do dig deep into dark places to do it's job, that's just how it works. I mean, yes, using Kaspersky is not wise. But given the amount of zerodays floating around these days, ANY software originating in hostile country is suspect. And people running critical infrastructure should be well aware of this.

  3. @Spacescifi NSWR also needs fissionables, so it's close to Orion as far as industrial production is concerned.  But might be better if you are after self-sufficiency. AFAIK all you need to replenish NSWR propulsion bus is to mix up  fissionables, water and maybe some moderator additive. Producing Orion charges is much more complicated process as mentioned above. And IIRC it also requires significant amount of tungsten. (Can nonfissionable uranium be used instead?)

    45 minutes ago, Spacescifi said:

    …the more powerful the bomb the more thrust an Orion would gain…

    I don't think it's that easy. Orion drive thrust is limited by pusher plate design. More powerfull charges will likely result in bumpy ride and breakdowns. But it is true that modifications of existing Orion ships to increase thrust would be simple compared to most other propulsion methods. And less need for cooling is definitely a huge advantage.

  4. AFAIK heavy elements like Uranium tend to concentrate in planetary core during formation period, so that is where I would start. I bet that 16 Psyche holds a significant amount. If I can't get my hands on piece of planetary core (read: metallic asteroid), I would look for planetary body big enough to undergo at least a bit of differentiation process, but small enough to dig deep into. (Ceres? Sedna?  Dunno if suitable candidate actually exists.) Last resort would be scouring small bodies that did not participate in planetary formation at all. These should be relatively richer in heavy elements then planetary crusts, but this would still involve processing huge amount of material. I see this as quite feasible if you have civilization that already process these for other usefuls, but certainly not as small scale ISRU operation.

    One other thing that comes to mind is filtering Uranium out of water. Now this would obviously be incredibly inefficient and not break even energy-wise, but if you assume some external energy source, it is only way I can think of that would involve a "machine" and not whole industrial base. Just drop filtering complex into seas of Europe or Enceladus, busy yourself for a few decades (!) and then collect small amount of fissionables (and other useful stuff too). Might be good for something like unmanned interstellar probe.

    7 hours ago, Spacescifi said:

    how feasible is manufacturing nukes in space with all theoretical futuristic tech we can bring to bear?

    Don't you think that going all  futuristic kinda defeats the purpose? Main advantage of Orion was that it could be realistically made with something like sixties tech. With sufficiently  advanced technology, it would make more sense to scoop hydrogen from gas giants for a fusion torch.

  5. On 4/21/2021 at 11:51 PM, SOXBLOX said:

    Didn't read the previous posts, but just put a pure-energy portal at the center of a star. Next, funnel super-dense, rapidly expanding core material out the back of your rocket. Free energy? No. Close? Yes.

    23 hours ago, kerbiloid said:

    An energetic channel from Sun to a planetary core can provide you with gold, platinum, any many other rare metals, when the core explodes.

    https://eldraeverse.com/2018/12/23/things-to-see-places-not-to-go-11/

  6. 3 hours ago, YNM said:

    They're planning to use NEAs exclusively. Their simulations involve "4000 random low delta-V targets" and they determined that 600 of them could be in a viable position. A lot of the bodies will have to be discovered first I presume.

    I am not talking about target selection. I am talking about weaponization. Anyone who can move rock to Earth orbit can also push it to collision course. Much less potentially destructive industries are heavily regulated everywhere and for a good reason. 

  7. On 1/5/2021 at 5:39 PM, Terwin said:

    Fertilization, gestation, birth, early development, and long-term health are not adversely affected in a way that cannot be effectively managed

    Not even counting any biological processes required for our survival being influenced in ways that we may not have noticed yet.

    Yes, this is serious objection as far as baseline homo sapiens are concerned. For how long that remains relevant is a different question entirely. Let's just say that Spider Rose would disagree and leave it at that :-)

    On 1/5/2021 at 5:39 PM, Terwin said:

    * Heat and cooling issues can be addressed in a cost-effective manner(without convection, and possibly even atmosphere)

    * Radiation, micrometeors, and other 'space hazards' can be sufficiently mitigated without a huge atmospheric blanket

    * Waste materials handling so that your waste slag does not end up killing you or someone else

    * Long-term life-support(including any 're-supply' resources) can be handled cost-effectively without reliance on 'deep gravity well' resources

    These are "only" engineering problems. Not easy ones, but I'd say way, way more approachable then "how to conjure orbital energy out of nothing" which is what you need for planetary industry to be competitive in interplanetary trade.

     

    On 1/5/2021 at 5:39 PM, Terwin said:

    * long range transport is nether too resource nor too time-intensive(the earth and the moon are very very close together as far as space objects go)

    I'd kindly like to bring to your attention our own history. Not only was transport in age of sail on similar time scales, but communication was too. I dare to say that managing commercial activity over inner solar system is easy compared to what East India Company had to deal with.

    On 1/5/2021 at 5:39 PM, Terwin said:

    your products are not destined for the bottom of that 12mk/s gravity well anyway(where all of the above problems are already addressed, so your solutions had better be damn cheap if you want to sell your products competitively on earth, and that is where all of the wealth and capitol currently reside, so paying to get what you need for a boot-strap process will leave you in a very deep financial hole if you can't deliver value to earth)

    Bunch of different stuff here. First, bootstrapping is definitely huge problem. But it does not affect my point - if you can't set up extratrrestrial industrial base at all, it does not make hauling stuff up the well any cheaper.  You just remain planetlocked.

    Second, if I take off-earth industry as given (which OP essentialy does) I don't care about space-to-earth trade. If Earth is net beneficiary, colonies are only that much stronger pulled towards independence. Once they became independent, it's interplanetary market what matters. And sitting at the bottom of deep gravity well is not exactly win there. So again, you are either planetbound or nonplanetary, with intermediate period of home planet dominace being relatively short and not economically stable. (If it were, Indies would still be part of British Empire).

    On 1/5/2021 at 5:39 PM, Terwin said:

    All of our current processes assume quite a lot about things such as gravity, convection, evaporative cooling, separation by density, etc.

    Assuming that living off-planet long-term is even possible, most industrial processes would need serious re-designs to account for things that are never noticed due to always being present on earth.

    That is not even a serious objection. It may be something of a bar to get over, but that is bootstrap problem again. And way easier to solve then economy. Our industrail processes are going through serious redesigns all the time, for instance look how iron smelting went from cities full of dirty sweaty wage slaves to bunch of suit-and-ties in a tidy control room. I don't mean that packing everything up for zero-g is easy, not by far. But I don't see any reason why it could not be done at all. And there is a rub, there are usefull processes that can't be done in gravity at all.

  8. On 1/4/2021 at 4:19 AM, Boyster said:

    If the belters can build megastructures then it only makes sense that Earthlings would be doing the same hundreds years ago before them around Earth and Moon.

    No it does not make sense at all. Show me a serious project where majority of resources is provided by Earth. Even earth-to-orbit space elevators count mainly on extraterrestrial resouces,  and I don't think you can get more earth-skewed then that. This is because they realize what logistics is about - if I can get to LEO cheaper from Vesta then earth surface, this means that Vesta is for their purpose (time insensitive cargo)  closer then planetary surface. (And  if you think that time is of the essence, just look how much cargo nowadays is transported by sea and how much is airlifted.) This gives earthlings a head at providing personel and light or time critical stuff, and even that does not extend much beyond  Moon.

    It is of course quite possible (in fact, probable IMO) that any early economic effort will bear name of some earth based corporation and/or be governed by earthly government. But industrial might behind it will be extraterrestrial, with all the centrifugal political force brought on by that. It will become independent sooner or later.

  9. Planetary chauvinisim strikes again. Belters outmatch Earth in resources by far, they will sooner or later outproduce it and without need to crawl up the freakin well. they can outcompete it so easily it's not even worth a try. And just you wait until they start producing suitable megastructures and outpopulate it.

    Face it, unless you came up with Star Crap magic propulsion, planets with deep gravity wells are irrelevant. Cradle worlds may trade in intangible assets as long as they are superior in culture or research, but that's about it. If we are talking logistics, what does need for hi-twr booster with 12km/s deltav mean for logistic chain? 

  10. Piece of my take on the matter:

    Quote

    Train
    Joining cargo (usually industry standard containers) into semirigid structure. Technically, it's tensile or spined (called "Babel tower" in this case) construction depending on how propulsion is attached. However, it is considered category of it's own due to specialized "sheparding" equipment and crew. Not much used in commerce, mainly due to need of constant attention just to keep it from breaking apart (and associated insurance rates). However, militaries just love the idea of throwing logistic together as needed, and assigning a few flunkies to sheparding duty is seen as small price for flexibility thus obtained.
    Most military logistic trains are tower types, built on decomissioned capital ship propulsion busses.

     

  11. Now that we have crew liquification covered, let's think about ship itself. If you just bolt pusher plate on ship that is not designed for it, you are essentially undergoing low frequency pogo from hell. Sooner or later, your ship will start to shed pieces and break up.  May take five rounds or five hundred, but break it will. Heavier ship will IMO just make stress greater.

    I can imagine it as emergency  way to show something heavy out of way with a blast or two, especially if you dont care much about damage to moved object. As a propulsion, no.

  12. On 12/15/2020 at 12:04 PM, Spricigo said:

    So, while I understand your desire for some why to learn it quickly, lots of practice seems like the way to eventually get it. 

    So true.

    I learned a lot about subject from tutorials and good people around here. But I did not really understand it until I parked a lab at low Mun orbit and started gathering science from all biomes.

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