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Everything posted by Terwin

  1. To the best of my understanding, metallic hydrogen is a form of solid hydrogen with a specific internal structure: http://ch301.cm.utexas.edu/imfs/#solids/metallic-solids.html There have been some experiments using super-chilled diamond anvils that have credible claims to having made solid hydrogen, and I think one of them even tried passing a current through it before it evaporated. So it is *possible* that metallic hydrogen has been created in a lab in microscopic quantities. The ISP benefit of metastable hydrogen is the fact that there is a huge energy released when metallic hydrogen decomposes into H2, and if there is nowhere else for that energy to go, you get *very* hot H2 atoms. Very hot translates to very fast for rocket exhaust, which in turn translates into very high ISP when you have very hot pure H2 exhaust. The down-side of this is that your thrust is low because your exhaust is very light. Metastable hydrogen would be great for inter-planetary transit, but might not even get an airplane off the ground. If you want a very high isp airplane, use a battery powered prop-plane. There is a miniscule amount of mass loss from the battery as the power drains from it, but you get lots of thrust by pushing against the air around your vehicle. I'm not even sure how to do the math, but I would not be surprised by an ISP over a million. (I think you use e=mc^2 for battery mass loss in this case) ISP matters most to rockets because once you are in orbit, (unless manned) you only care about mass-efficiency, and ISP is a measure of mass-efficiency. For airplanes, cost-efficiency is a much more important metric, and a fuel that would cost more than an equivalent weight of multi-carrot diamonds is not in any way cost-effective.
  2. Do the QD connections require human assistance to connect? Any thoughts on the propellent aggregator keeping the fuel super-cooled? Would it likely even keep the fuel cooled aside from venting to keep the pressure reasonable? Presumably they would like to keep at least some fuel for extended periods(such as a buffer in case of losses during fueling), but I would expect cryogenic fuels to require active cooling and I do not recall hearing anything about that.
  3. A flexible tube would probably require an EVA, and I believe the current plan for loading up the fuel depot only involves unmanned flights. Extending a prehensile fuel line sounds like a significant engineering challenge, and no relevant results pop up on google for the term.
  4. So tungsten and DU pellets provide Looting deterrence as a fringe benefit? nice.
  5. Generally I generate funds with contracts, using an ISRU-equipped, nuclear powered vessel carrying an engineer(for drilling&refining) and some means of improved control(pilot, drone pod, or guidance thingy that lets the engineer drive like a pilot) and a load of tourists to go and fulfill base-building contracts on both The Mun and Minmus tends to provide quite a lot of funds(and the opportunity to fill-up the remaining seats with kerbals below 3 stars to get more experience). I generally have 2 main variants saved: with lab and without. On top of the base building and tourism contracts, the occasional flag planting or ore collection contract is just icing on the cake.(admittedly, any 'and return that ore to kerbin' leg is handled with a pod strapped to an ore tank that 'lands' by picking up or putting down landing legs, because my usual designs do not have a lot of landing margin, especially after I unload any ore and most of my remaining fuel at the orbital fuel depot)
  6. I would expect it to be ok within scavenging range, but I generally dropped my unmanned mining outposts as a single unit, so I cannot say for certain. (I find a larger launch/landing vehicle to be easier than pin-point landings, and an unmanned mining outpost is usually simple enough to fit into one launch) Note: remote outposts will need to be visited for their resources to load into the planetary warehouse, WOLF is intended to replace those scattered outposts with an alternative that does not need active maintenance
  7. Beyond this, how many launch consumers are waiting to send ~ 100t to LEO for less than $60m on Starship compared to ~60t to LEO for $90-150m for Heavy? Hyping your next-gen product(that is both much better and much cheaper) does bad things to your current sales, even more so when the new product is expected to be available in a time-frame similar to the lead-time for both the current product and your ability to make use of it.
  8. Last I checked, you need logistics to push as well, but it need not be manned. The unmanned material processors have logistics to support pushing from unmanned processing facilities.
  9. This page: https://en.wikipedia.org/wiki/Research_reactor#Research_centers Lists 35 active reactors and 17 decommissioned ones Although this page: https://en.wikipedia.org/wiki/List_of_nuclear_research_reactors seems to list a lot more reactors than the 52 on the other page(including decommissioned Manhattan project reactors), so I guess it just depends on how you define a research reactor.
  10. Near the end of the video, they mention a number of people that worked on Colossus who then went on to do big things with advancing computers. While many people who were not involved in Colossus still considered electronic machines of that scale to be impossible/unfeasible.
  11. According to this video, a post-office worker who was always denied the opportunity to build an electronic sorting machine put a lot of his own money into building a huge code cracking computer to counter Enigma. After the war, his Post office superiors continued to refuse permission to build the sorting machine because it was larger than thought possible, but many of those that worked on the anti-enigma machine went on to be foundational in creating general digital computers So, considering that the man with the vision to start the process only did so due to the war(using his own money for the first version after getting turned down by the war office because it was deemed impossible), it is entirely possible that general digital computers would still not be a thing if not for WW2 code breaking. I cannot imagine this would have been good for rocketry.
  12. We could use your support over here in the 0.1% club(6'6"/2m+). (I can't even drive a Tesla model 3)
  13. This argument becomes much stronger once there is more than one alternative launch provider with the needed capability. 'Not keeping all your eggs in one basket' may or may not be just an excuse, but it is sufficient reason not to scrap SLS yet, especially when Starship is not yet flight-proven. SLS might well stick around as a project until both New Glen and Starship are crew certified. (I hope that they would let it die at that point, especially if it has not yet flown)
  14. Probably transmission power and spectrum licensing. A smaller receiver requires a higher power signal to receive clearly. I believe part of the transition to digital broadcasting was intended to free up part of the TV spectrum for other uses, so you would probably need a license to broadcast on TV frequencies, and as I think those are regional, you would need a lot of them if you are broadcasting from a satellite(assuming you could find a frequency that is not already licenses in part of your service area).
  15. By my understanding, you are asked to swear on something you hold sacred(traditionally an appropriate religious text like the bible for Catholics or protestants), but the court can only go after you for falsehoods they can prove you knew were false, or more often, contradicting yourself(which means you must have lied at least once) I am hardly a lawyer, and it is entirely possible that taking the 5th is a silver-bullet for any question you do not want to answer in a criminal case(but be careful because they may try to trick you by asking things in different ways). Taking the 5th for every question, is sort of like refusing to talk to the police without a lawyer present. It is the safest way to go but may cause a lot of head-aches(like turning a speeding ticket into an arrest because they do not have a lawyer for you sitting in their back seat). If you are or may be under suspicion for a crime, then you really want to talk to a lawyer before taking the stand, because that is their field of expertise.
  16. Taking the 5th is roughly the same as 'I do not wish to comment on this and the constitution ensures that I cannot be coerced or punished for that' It may not be the truth they are asking for, but it is still a full and complete truth in and of itself. If you are called to testify, you can take the 5th on everything(up to and including your name), and there is nothing they can do so long as you are consistent. (if you answer a question for one side, the other side can ask questions about that, and I am uncertain if you can take the 5th on a topic after already talking about it) The prosecution can try to take advantage of this by asking you questions that make you look guilty to the jury if you refuse to answer, but that is all they can do if you consistently take the 5th.( to the best of my understanding, not a lawyer)
  17. I strongly suspect that modern stealth aircraft could be below the noise floor of early radar.
  18. Unless things have changed, MKS drills do not work on non-planetary bodies. The stock drills are the only way to harvest asteroids, but I think? that they will fill any sort of ore storage you have on-board.
  19. He was talking about recreational diving, 50m is a good 34 feet deeper than the recreational diving limit, so if that was 'according to plan', you were not doing recreational diving. Also, when I was certified (2014) they were no longer teaching 'no stop' dives, and every dive requires a 3 minute safety-stop at 15 feet. He also specified 'fatal' decompression sickness. A far as I can tell, it looks like you survived both of your cases, even though neither dive complied with the current recreational diving guidelines.
  20. You can always send a rover with a Klaw and additional drills/power. Also, as it will use the stock catch-up mechanic, you can also do other things(including fast forward at KSC) then come back from time to time to let it catch-up.
  21. When the storage tank of your water miner gets full, it should automatically deposit half of its contents into planetary storage. This also happens between 'chunks of the stock 'catch-up' mechanic which lets processes like ISRU 'catch up' to the current time by processing 6 hour 'chunks' of the back-log at a time. Once you have water in your (Minmus) planetary storage, if you have a MKS process which consumes water turned on and attached to your empty water tank, it should attempt to 'pull' water from the planetary warehouse to fill the tank. note: Kerbals count as a MKS process that consumes supplies for the purpose of pulling supplies from the planetary warehouse.
  22. As we have binary(and trinary) star systems, and the only required difference between a star and a gas giant is the total mass(ie heavy enough to maintain fusion), I see no reason an early star system could not have one or more gas giants(aka brown-dwarf stars which are not the system primary)
  23. I remember seeing a picture of a prototype door section at Starbase. While enlarging a fairing is non-trivial, it is something that we have seen on a number of rockets without causing major problems or vehicle re-designs. Unless I am mistaken, currently a starship can support it's own weight without being pressurized. Put those together, and it sounds like the changes to go from test vehicle to cargo vehicle fall into the 'known solutions' category. Also, I think I remember hearing mention of a 'stretched fuel delivery' version? If they try testing with this configuration, they might only need to move the tank bulkheads and add the door-version of the top section as far as design changes needed to get to a cargo carrying vehicle.
  24. Falcon 9 usually lands inside the rings on the barge using a margin of error of less than a second to get the hover-slam correct(margin provided by the throttle range of the engines in use. I have not done the math, but I would not be surprised by a margin of 0.1 seconds or less). Super Heavy and Starship can both hover. This provides a margin of error in the range of multiple seconds, possibly even a minute or longer when testing and there is plenty of fuel available. I'm not sure about you, but if I can generally do a job in X time, and I am given 10x or 100x to do the same job, it gets a whole lot easier.
  25. You might have greater success with a water rocket. https://en.wikipedia.org/wiki/Water_rocket That gives you non-instant thrust with no worries about reaction rates, hazardous materials, or fire-codes. It is also very easy to come-by disposable launch vehicles(aka soda-bottles) if you build a launch stand for them.
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