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Everything posted by Terwin

  1. Just use an earlier version to build up your infrastructure(I plan to upgrade after my currently duan-bound fuel-drone, fuel-station, and mks-transport arrive and set up a transit. (I'm planning to copy over the bases and transit routes after I get the depots established in a 1.12 game)
  2. If you are interested in using stored energy to propel perhaps a couple hundred pounds tens or even hundreds of meters horizontally, you might want a lower density medium. Elastic cords come to mind, probably something between the foot-long 'bungee' tie-down cords with hooks on each end you might find in Walmart and the kinds that people use to jump off of bridges. If you want a more rocket-like high acceleration/short distance acceleration approach, use a 'horizontal sling-shot' type of set-up, or for a more manageable acceleration, you can tie one end to something fixed(like a tree or lamp-post) and walk it back to your launch spot. In either case, using elastically stored muscle power tends to have fewer accidental catastrophic effects over using high-pressure gasses generated by rapidly converted chemical energy. Should also be less expensive and more re-useable too...
  3. Did you fill the greenhouse with machinery? Zero machinery will also cause that result, and if it is inflatable, you probably did not have any on there at launch. Also, I am not sure that the greenhouse will affect the listed efficiency as opposed to the actual production. Take a look at the production rate(in the resource panel) both with and without the greenhouse, and that may better display the change.
  4. But the primary capability of SLS has nothing to do with space, it's primary capability is in securing jobs in 'key districts'. As such, Starship cannot replace the primary capability of SLS. Once Starship is human rated to be *safer* than SLS, and has *all* other capabilities(including horizontal integration should SLS offer that option), I expect SLS to be re-designed(and possibly renamed) to provide some purported capability that would be counterproductive to add to SS. SLS will only truly die when those 'key districts' are no longer 'key districts'. Even as a tax-payer I can't say that I mind too much. SLS is a trivial part of the budget and part of what it(and it's predecessors) does is to keep some space related specialist knowledge active and available. (I would be surprised if SpaceX and other 'new space' companies did not benefit in some way from the knowledge and experience kept alive in these post-shuttle projects)
  5. If cost competitiveness was a real concern it would not have been designed or built as it was. For good or ill, so long as it has sufficient backing in the halls of government, SLS need not worry about any sort of cost-based competition.
  6. I have difficulty thinking of a single sci-fi trope that is not at least 50% nonsense, and the vast majority of them are 100% nonsense. So, yes, that specific trope is also nonsense. (most of the sci-fi tropes that are less than 75% nonsense have already been made into reality in some form or fashion, such as flip-phones being a real-live alternative to Start Trek TOS flip-open communicators, or submarines and the Nautilus; and thus not really a sci-fi trope anymore)
  7. Sorry, my google-fu failed me. (if only I had some common-sense to back it up) ISS orbital velocity: 27,600 kilometers per hour -> 7 2/3 km/s (ref: https://planetseducation.com/international-space-station-orbit/ ) So it only takes ~24 2/3 km/s of delta-v to follow the specified trajectory(assuming little or no atmospheric drag for take-off) As we have seen in Star Trek, Star Wars, Battlestar Galactica and other science-fantasy; this is clearly not an issue, and vehicles the size of a large van or small bus can repeatedly make such trips with a cargo fraction of 80%+ In the real world, Falcon 9FT is 549t and can loft 15.6t (22.8t expended) for a cargo fraction of ~2.8%(~4.2% expended) Stage 1 dry-mass: 22.2t - 1 falcon9 engine no longer needed on 2nd stage: 0.47t =21.7t cargo capacity without staging: -6.1t (1.1t expended or 0.2% ) Giving the STSO ~4.8% of the efficiency of the tsto using this rocket(the most updated version of one of the most recently developed rockets that currently exists) Also note that this is fully expended, so actually being able to land again would greatly reduce this. Even if we assumed that the first-stage tanks are massless after their normal separation point and we only need to carry 8 additional engines to orbit(engines are only ~19% of the first stage dry-mass btw), that puts us at 11.8t or ~75% of the tsto performance in this scenario(and this requires either staging 21.7t of empty tanks or a ~80% dry-mass reduction only applied to the SSTO) So yes, a fantasy-tech ssto can indeed beat out a real-tech tsto, but if they both have access to the same technology, then the TSTO will trounce the SSTO every time.(Martians and Lunites can have useful SSTO with current tech, but even there TSTO will be more efficient)
  8. I would suggest that your meaning is not nearly as clear as you seem to think it is, thus the questions/suggestions. Earth orbital velocity: just under 30km/s Time to orbit: 8.5 min(for the shuttle) 8.5*60*9.8=~5000m/s (used as gravity loss estimate) means we need at least 70km/s without aero-breaking (or accounting for air friction during launch) So just calculate the fuel fraction for the isp of the engine you want to use and see if it is feasible(and no, anti-mater + pusher-plate is never feasible under the laws of physics as we currently understand them, so use something else)
  9. Isn't that just a miniature lab? So if you want the bigger version, just use the stock lab(2 scientists, and lots more science storage, but not inflatable)
  10. In fiction, the author defines the laws of the universe to suit the story. In historic fiction or hard sci-fi, most of the changes are social rather than playing around with physical laws. On the other hand, if the author wants giant transforming humanoid mecha spamming missiles, then they add some sort of change that makes such things practical(reflex technology in the case of Robotech/Macross for example). If the Author wants fireball spells, dragons, and magic swords, then they add Magic to the mix. In short, you identify what you want for your story, then choose if you want to just hand-wave it into existence with no explanation, create a cultural or technobabble reason for what you want, or use existing period-appropriate technologies(does not work beyond technologies currently in-use). Anything else is pretending expertise and foreknowledge that you do not have and which will be transparently stupid to those who know better. For examples look at the science fiction hall of shame thread.
  11. Looking at Cost-per-science accounting by itself, probes currently make a lot more sense than humans. Even if a human can get and order of magnitude more science done than a probe in a given time-frame, a probe is probably two orders of magnitude cheaper per time-frame(in part because they can last an order of magnitude longer(or more, looking at you voyager and opportunity) using rtg/solar and in part because it is probably an order of magnitude cheaper without life-support or the ability to come home). The primary value delivered by human space flight over probes is more related to inspiration(and leveraging national pride to get funding in the first place), not maximizing science per dollar spent. After all, how many people remember the Luna probes, Ranger probes, or Pioneer 4 compared to Neil Armstrong?
  12. I took that statement as an expression of frustration from someone embracing a fail-fast philosophy encountering real-world processes that do not support that philosophy. I am sure it does not help that it is probably expensive to scrub when otherwise ready to launch.
  13. That does not clarify much, as a low-density but electron-rich 'plume' could easily be visible if against a dark background. Also, the temperature of the plasma maters a great deal. Even though your fire-place poker has little to fear from a wood fire, it was originally created by being melted in a different(much hotter) fire, and it could be vaporized by an even hotter fire. And all of those fires have plasma much cooler than the plasma in the heart of the sun.
  14. Economic inertia can be a powerful force, and it can take a visionary with deep pockets to disrupt it(see Elon Musk regarding reusable rockets) I would not expect Thorium plants to enter common use unless and until uranium is no longer easily available(which likely also involves digging up old 'used' fuel rods and re-processing them). But if you are talking about 'limited stocks of uranium to fuel nuclear fission' then Thorium has a place in the discussion, as it is an entirely viable option for once the fuel cost of using uranium gets too high.
  15. neutron+Th232-> Th233 (hl 21 min)-> Pa233(hl 26 days)-> U233 U233 produces 2.38 neutrons per neutron capture, allowing this process to be self-sustaining. (Ref: https://www.radioactivity.eu.com/site/pages/Thorium_Fuels.htm ) I find it odd that you would classify the fertile fuel source to be a passive element. Sure the easiest way to kick-start a thorium reactor is using either plutonium or previously produced U233, but that is just the kick-start. There was a research device where they omitted the breeding blanket in favor of taking neutron measurements where the concept was proven to work: https://en.wikipedia.org/wiki/Molten-Salt_Reactor_Experiment I did a quick check of https://en.wikipedia.org/wiki/Fusion_power and it only lists Hydrogen(including duterium and tritium), helium, and boron as potential fuels. Would you care to provide a link where fission provides anything more direct than providing the electricity to run the lasers to initiate fusion? Unless I missed it, it seems that no one has bothered to update Wikipedia with this approach that you claim has been the best option for fusion power for the last 40 years. The molten salt reactor design should be able to most if not all of the thorium. The only hybrid fission-fusion devices I have ever heard of are nuclear bombs, not reactors, there is a *big* difference. Not all reactors waste fuel the same way, the reasons fuel pellets are not re-processed to extract the remaining useable fuel are cost and politics, short term it is cheaper to just discard them, long term is it more expensive, but balance sheets are reported quarterly, not per decade. Those 'highly radioactive fluids' are molten, and would quickly solidify if exposed to an uncontrolled environment, basically containing themselves. If you wish for me to consider any additional replies, please include references to support your claims, in particular that 'hybrid fusion-fission reactor' design that you have been touting as the cure-all for the world's future power problems.
  16. Th produces U233 which then splits and turns more Th into U233. You need some neutrons to start, but after that it is self-sustaining. Liquid Salt is the preferred design for Thorium reactors, this includes a fuel reprocessing step that separates out the U233 to send into the core and the used/poison fuel which can be dumped. As we are dealing with liquids instead of specifically designed fuel pellets, it is a lot easier to keep using the 'unburned' fuel, as you need to chemically separate out the U233 already, so removing the depleted fuel at the same time is not a big addition. Not being able to afford to dispose of the Thorium ore as 'radioactive waste' is a big part of why rare earth mining in the US could not compete with rare earth mining in china. Turning that cost center into a profit center might well help resume rare earth mining in the US. Outside of nuclear bombs, I am not aware of any fusion designs that utilize fission for ... anything. When you say we need to reserve fission fuel to use for fusion reactors, to me it sounds a bit like saying we need to reserve horse-feed for use in automobiles. (Or that you want to scour the earth clean of complex life using fission pumped fusion bombs)
  17. As someone who finished without even going orbital, not sliding off of ladders seems like something that would already be pretty much solved by those taking advantage of orbital reports, so I do not see it mattering much as far as I am concerned. You still need to keep them from being pushed off by drag or other forces, even if they no longer slide around once in orbit.
  18. According to This Article we currently know about roughly 230 years worth of uranium fuel at current usage, and further exploration is likely to double this.(not including things like sea-water extraction) But Uranium is not the only option for fission, Thorium is more common than Uranium and roughly 100% of Thorium is useable as nuclear fuel(as opposed to 0.7% of uranium). There was a research thorium reactor that showed Thorium can be a safe and reliable power source, extending the potential life-span of nuclear fission by more than 100 fold(into the tens of thousands of years). Fusion will be great if/when we can get it to produce power in an economic fashion, but we are not there yet, and there are a lot of hurdles yet to pass to get there. Perhaps fusion will be our power source in 20, 50, or 500 years, but for today, nuclear fission is the safest, most reliable, and least polluting power source currently available. (most co2 pollution from nuclear plants comes from making the cement used to build them, similar to Hydro, but dams use more cement per kwh)
  19. Flex-tubes are kraken bait. RD implemented disconnected bases just to prevent this sort of issue.
  20. Sounds like a combination of the subconscious recognition of eyes looking at you and drivers trying to be aware of their surroundings.(or pedestrians trying to be aware of the large metal murder machines near them) I try to look around on a regular basis when driving so as to A) be better aware of my surroundings and B) prevent 'roadway hypnosis'. I also tend to look around when walking if I hear vehicles near-by.
  21. 1) the system need not be static, it could easily accelerate to closely match the current speed of SH 2) SH can hover, so there need not be any significant velocity at initial contact, nor any significant initial load, as they can reduce thrust after initial contact until the last engine shuts down.(sort of like one parent letting go of the baby after the other parent has a firm grip)
  22. I think I remember an idea about putting a large spinning magnet at a Lagrange point to deflect solar wind? Not terribly practical as I think it would take multiple SS loads just to get it to orbit, but certainly possible.
  23. I could see an argument that the ejecta of a sub-orbital, fully depleted stage would provide less total hazard than the same stage, mostly depleted and in a lunar orbit(probably not long-term stable)
  24. Building engines in higher quantity will generally reduce the per-unit cost, be it a singe or multiple use engine. A commercial jet engine is deigned for high reliability, low maintenance, and a high rate of use(possibly even more run-time than non-running time: running for multiple hours then refueled and re-started after a quick maintenance check). Orbital rocket engines burn for tens of minutes(if that) then coast for hours and may or may not burn for a few more minutes. SH *might* get below a 1:5 burn:idle ratio (10 min burning up, 5 min burning down out of a 25 minute flight and < 50 minute time on the pad before the next launch might be a best-case scenario for re-use) Also, for an airliner with 2 engines, 'engine out' capability is not something you want to be relying on, but with >25 engines on SH, even one failed engine per launch is not critical, just annoying. (and long-run-time reliability is very expensive)
  25. Flex tubes are kraken bait. The recommended approach is disconnected bases(supported by MKS) which are supported by WOLF support bases.
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