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Everything posted by monophonic

  1. IDK about SpaceX, but NASA has been investigating using local materials for housing structures. So how much would you save from that mass if all of foundation, floors, walls and roofs were made from martian minerals? 90%? Presumably surface materials like wallpapers/paint, flooring, probably window glass, etc. would still be brought from Earth. Most of dome material as well, I think. Could there be weight savings by accepting a large number of small(er) domes? Then if you accepted a more european standard of living? So halve the average floor area per capita desired. That doesn't exactly halve the mass requirement, because all rooms still need four walls etc., but it should still be a significant reduction. Could drop it even further if going eastern europe level. Of course this will make recruiting new martians harder, but let's have that discussion another time. I don't think any numbers we might reach will make Mars City happen in our lifetime. I'm just interested how the numbers change if we adjust some of the assumptions slightly towards more realistic.
  2. Practical experience tells that, for squishy meatbags i.e. humans, the limit is 9g and even that only for a very limited duration. Meanwhile smaller non-squishy things are turning in excess of 60g and functioning like a machine, i.e. what those missiles in fact are. If it wasn't far more efficient to have the light weapon do the turning instead of the heavy launcher, manned aircraft would have been replaced with drones in air combat long ago.
  3. Well, for a stationary target you just head straight at it. This also works for moving targets as long as they move slower than your robot. That is called pure pursuit and is an unoptimal strategy though. Improving from there depends on what kind of sensor your robot is using to track the target. If your sensor gives direction and range, you can track the target for a short while to get its motion vector and use those to calculate where to move your robot to hit the target. If you only get direction, you can steer to keep the angular velocity at zero. This has two solutions though, and only one closes in on the target. The other steers you away from it. You can distinguish them by whether the direction to target is closer to the nose or the tail of the robot.
  4. Russia has used depleted uranium in fragmentation warheads. I know Finland withdrew their R-60 air-to-air missiles from use over public concern of DU. (They probably didn't have much life left in them anyway, but I digress...) I do not think this is the case here though. This photograph is taken in 2013 when the Minsk was a theme park in China, so the paint job including the anatopistic NATO designation is probably of chinese origin. Since this location was most likely publicly accessible, I consider it most likely that the radiation warning sign is a sticker stuck there by some self-proclaimed peace activist. Most people inclined towards that behaviour that I have met (which is not many, I admit) would not have been able to differentiate a giant pencil from a nuclear ballistic missile. A conventional anti-aircraft missile would look like an ICBM to them.
  5. My apologies. I didn't mean to imply that. What I tried to communicate was that I think the source of the issues is 100% at the management level and cannot be fixed if fixing is not started there. But that has been quite thoroughly discussed since my last visit to this thread, I feel. There used to be a tradition, in our air force, that after a major servicing the chief mechanic who worked on the airframe was on board during the first flight. I don't know whether that is still a thing, although certainly it isn't possible with single seaters like most fighter aircraft are. But that would certainly have provided motivation to do the maintenance properly.
  6. It is starting to look like Boeing's management has been making some very big mistakes, in my eyes. And the system is catching up to them finally, I hope. The MCAS issue certainly wasn't caught before catastrophe. It may have been the "keep your seat belt on at all times" rule that was the last line of defence that prevented fatalities in this case. A bit too close for comfort for me.
  7. Mayhaps. I think among other things Boeing acquired this "open door policy" with McDonnell Douglas. See https://en.wikipedia.org/wiki/American_Airlines_Flight_96
  8. I agree the obvious instinct is to get as far away from the danger as possible. That said it is also common sense to not cut loose the strap keeping you tightly attached to your seat. So whichever instinct wins may vary from person to person. Anyone who was not seated and strapped yet is still inside the plane is likely to flee of course. All I hope is I don't have to find out which instinct would win in me.
  9. Could be just the angle. Zooming in especially the first image it becomes clear the black "plate" behind the nozzle is actually conical in shape, and its rim is clearly some distance off the backplate of the airframe. (Spaceframe?) Parallax from this offset could explain the apparent difference in engine position at these viewing angles. So the planned X-37C? Could probably still happen if a customer is found, but it might be tough competing with the Dream Chaser in the space plane category and CST-100 on the Boeing line up for commercial uses.
  10. This side of the arctic most radio stations have streaming available for free, so you could forget the FM. Any old cell phone + cheap bluetooth speaker can replace the radio set entirely. Assuming of course you can get wifi or cell reception (+ cheap data plan) in the shop. You wouldn't even need to set up any playlists if your favorite stations stream online.
  11. Mine set off the biggest fire crackers they managed to scrounge together and dance around menacingly dressed as cachalots* to scare off the Kraken and bring on a new year of only planned rapid disassemblies. *I wont tempt the forum censor module with the name this marine mammal is usually known as. A famous, although fictional, individual was white.
  12. You are missing the LEO to TLI burn. In your link scenario 2 the first Blok DM send the entire stack from Earth orbit towards the Moon. The second Blok DM eases the stack to low lunar orbit. Finally the Fregat is sufficient to send the remaining vessel back towards home. You could use the information from their mission plan to calculate approximately how much dV they have budgeted for each part of the mission. Then compare that to what you were considering.
  13. Awesome. Sadly said site does not open for me. Not without a VPN at least and I have too much going on to dive into that too. So I could not have found that out by myself.
  14. Maybe someone who shares citizenship with NASA could make a FOIA request for it? Should I be so bold as to suggest they might also release it globally for the rest of us to enjoy? IDK how precisely one has to identify the stuff they request in the USA, but here in my country the information in this thread is sufficient that the officials are required by law to help identify the exact document.
  15. What's changed is not only minute details on the cathedrals themselves but also the surrounding environment. Typical city around a cathedral is now very well lit, meaning the phenomenon may well still exist but is invisible in the flood of light. There are also hundreds of lightning conductors on the surrounding buildings which route their own share of the electric charge in the ground, meaning the charge available to light these fires at any single point is much less. Finally as the phenomenon is now well understood the church decorations have in many places been modified to reduce it. (Mainly to avoid lightning strikes though but the measures are the same.) E.g. sharp points have been rounded or small orbs attached at their tips.
  16. Sufficiently spaced out network of individual habitats and evacuations of threatened ones. I.e. how we manage predictable disasters here on Earth right now. Hurricane heading towards Florida? Evacuate. Volcano getting ready to erupt under Grindavik? Evacuate. Asteroid on course to hit Hellas City? Evacuate. There has been a lot of talk about potential methods to deflect threatening asteroids. The problem is that all the feasible ones have to be implemented a long time before inevitability of impact becomes apparent. That means sufficient funding is unlikely to be allocated in time to be effective. Improving technology will eventually change that, but there is still a long way to go.
  17. (TL;DR: No.) The question of minimum viable population (use this as your search term) doesn't seem to have a single clear cut answer. For a short-ish period, whatever may count as short-is, as little as fifty individuals might suffice. For very long term i.e. from here on out to eternity, the estimates seem to hover around a few thousands. Ten thousand seems like a safe-ish bet. The long term threats are major catastrophies and inbreeding. The population doesn't all have to live in the same physical colony as long as there is sufficient movement between the individual habitats to keep their gene pools effectively combined. Dividing the population to multiple habitats also helps protect against catastrophies, if there are enough survivors even if a meteor strike takes out an entire habitat and its inhabitants. Active measures such as that icelandic "cousing detector app" or even genetic testing can help prevent inbreeding depression (another search term). The testing comes with a hefty can of worms raising questions of moral nature, though. So, assuming everything else is truly equal, the required population numbers are equal. If one type has e.g. better radiation protection, there may be minor differences for shorter periods of isolation. Long term I expect those to disappear into the noise. https://en.wikipedia.org/wiki/Minimum_viable_population
  18. I couldn't find it now, but when I played KSP1 a lot I had a spreadsheet to plan my missions. I used dV maps calculated by others and the rocket equation to calculate the dV available in my designs. So rocket equation and those to calculate the dV requirements for transfers should get you far.
  19. So you do advocate the no rush plan after all. Musk, and thus by extension SpaceX (as he is the CEO and majority shareholder) has been quite explicit about skipping all that research and going for the mass emigration phase as soon as they can build enough Starships.
  20. I'm certain he meant exactly that, but as has been mentioned it makes no difference. So I jumped forward to what might actually do something. Actually I originally though about a semicircular beam that rotates around its center, but that might be overly complex to get set up right. Reading the newer posts it does seem other effects like those you mention dominate anyway.
  21. Maybe, if the rotating beam covers only a portion of the hole at a time. For a precision drill you want to outright vaporize rather than melt the material anyway. Then you need to get the vaporized material out of the hole. The only route out is the one the laser beam is entering, so the material disrupts the beam and thus your drilling efficiency. A partial cross section beam would leave space for the material to exit, but you would need to rotate or otherwise move it to keep creating the open space as the hole deepens. This is not entirely unlike how a CNC router creates a hole bigger than the bit in use.
  22. Oh my, that was an appalling read. Anyway, it will be very difficult to sweep stuff under even that large a rug and not leave any bumps to tattle in today's society. Most people would have some family or friends expecting to hear back from them and start asking questions if they don't. So if stories of injuries can be suppressed, there would still be stories of people suddenly going completely unreachable for no apparent reason.
  23. Right, let's get to it! We must build a thousand Orion ships to get enough mass to Mars to build that self sufficient colony, prompt! Never mind what launching all those does to Earth. We don't need Earth when we can have Mars! Yeah, that's reductio ad absurdum for you. Mind that not rushing does not mean sleeping in the bushes as the turtle crawls past either. It is just way too early to try to run (build planetary colonies) when we have only just learned to roll over (build LEO space stations). There is so much we must learn before we can build a Mars colony that can be learned much closer to home i.e. cheaper and safer. Worst thing to do right now would be to build a colony that fails and kills its inhabitants. That would make any and all funding and support shy away for generations if not forever.
  24. Meh, that's peanuts to your true economic potential. Rent out your spare brain data processing capacity to the AI technocore for real profits.
  25. Yes. Traditional ballistic missiles have tried to maximize range by lobbing the warhead in a high ballistic trajectory. This means the warhead is relatively slow at the midcourse phase. HGV trades range to minimize time-to-target. The booster tips over very hard very early and pushes the warhead to very high horizontal velocity while still in the lower atmosphere. Mid-course interceptors are useless here because the exoatmospheric kill vehicle has no aerodynamic cover and thus cannot even survive flight inside the atmosphere. Traditional ballistic missiles could be used in a similar fashion. This is called depressed trajectory. HGV "just" optimizes the warhead for this profile and usually provides it with some maneuverability at the same time.
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