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Everything posted by KSK

  1. Oh good luck with those! Hope they went / are going, okay.
  2. Bonus version either doesn't work or requires a complicated trajectory to reach a stable orbit. If you're firing into orbit, you're firing into a closed trajectory by definition. The problem is that any closed trajectory starting from the ground finishes at the ground, so at best you get a single orbit then kaboom. Conceptually, the easiest way to avoid that is a rocket burn at apogee (highest point on the orbit) to raise perigee (lowest point on the orbit) to an altitude above the atmosphere. The complicated way involves maths and visualisation skills that are beyond me but apparently in a three body system (e.g. Earth, Moon, Sun) it's possible to use the the gravitational fields of the other two bodies to effectively do that orbit raising for you. I have no idea how often the Earth, Moon and Sun line up in just the right configuration for that to work though.
  3. Just saw Dune tonight and yeah - I’m with @Gargamel. I love Villeneuve’s sci-fi stuff (must see some of his other films at some point), so I’d been looking forward to this for ages. It did not disappoint.
  4. Being slightly snarky here but... horizontal gene transfer. It's the thing that lets bacteria evolve so damn fast - and if there's one order of life on this planet that's adapted to live just about everywhere, it's bacteria. Edit. Apologies - snark aside, you do make a very good point about not being stuck in a niche being a good survival tactic. Although I do wonder if humans have kind of gone out of the other side of that strategy with modern civilization being quite so hyper-specialized. We've built, or are building, our own specialist niche and it's becoming increasingly easy to disrupt.
  5. As with many things, Douglas Adams nailed it. “For instance, on the planet Earth, man had always assumed that he was more intelligent than dolphins because he had achieved so much—the wheel, New York, wars and so on—whilst all the dolphins had ever done was muck about in the water having a good time. But conversely, the dolphins had always believed that they were far more intelligent than man—for precisely the same reasons.”
  6. Phosphorus too? That turned out to be pretty important for life here. It’s also a nice illustration of your point that life will evolve using what’s available given that phosphate groups are key to metabolism (ATP), holding genetic material together, cell signalling (second messengers plus protein phosphorylation in general), skeletal structure (calcium phosphate), and wear resistant surfaces for teeth (apatite). For that matter, the first three make your point even more loudly: adenosine monophosphate being a component of DNA, adenosine triphosphate being the ATP mentioned above and cyclic adenosine monophosphate being a key second messenger in signal transduction. Plus cyclic guanosine monophosphate of course, another repurposed DNA component used for a second messenger. I love biochemistry. It’s full of these kinds of repurposed bits and pieces.
  7. Yeah, that's the big question. It's quite possible to make DNA analogues using non-natural nucleobases but whether those nucleobases would arise spontaneously...? I don't know. Maybe it's DNA or bust because that's just how prebiotic chemistry works. The genetic code though, I'm struggling to see as anything but arbitrary. Why does TTT code for phenylalanine but CTT code for leucine? Was it chemically inevitable for an enzyme to evolve that couples leucine to that specific tRNA? Or was that just how things happened to turn out on Earth, and somewhere out there is a planet with DNA/RNA based life, in which TTT codes for leucine and not CTT? For that matter, why do codons have three bases? Again, one answer is that it allows for 64 unique sequences (assuming you always read them in the same direction), which is a good balance between coding for enough amino acids to make a diverse set of proteins, whilst allowing for enough redundancy that mutations don't automatically muck things up. On Earth, that's worked pretty well. But maybe on a planet which suffers from higher radiation exposure, (or other environmental factors that lead to a higher mutation rate), life is based on DNA again but with 4 bases per codon, to allow for much more redundancy to guard against that higher mutation rate. This is all pure speculation of course and the kind of thing that reasonable people could reasonably disagree about. For that matter, it may never be scientific speculation (in the falsifiable Popper sense), so is it something we should even be discussing on a science and spaceflight forum?
  8. In that case I stand informed. Thanks @FleshJeb
  9. Well malicious damage is very easy to solve - you don't solve it. As a starting point, macerators are a thing and would probably be quite helpful in a spacecraft toilet for chopping everything up and making it easier to move it around the system. Chopped up waste would also make vacuum drying quicker and more effective and, as mentioned previously, vacuum drying would be a sensible part of any spacecraft waste management system. The treatment process now becomes: chop - vacuum dry - incinerate - process resultant gases. Any idiot dropping their cocaine stash down the toilet has just presented the system with a slightly different source of carbon, hydrogen, nitrogen and oxygen. As for any idiot that tries to flush anything that the macerator can't handle (whether through stupidity or malice) - well a jammed macerator triggers the lock on the toilet door. There is then a ship-wide announcement that the toilets are out of order due to a passenger caused blockage. The remaining passengers are kindly reminded that personal faecal containment garments and personal waste disposal bags can be found in their cabins. The door then unlocks, letting the idiot out. Nobody dies and everyone knows exactly who the plumbing wrecker was. Naturally, this procedure is fully disclosed in the terms and conditions of travel, and is also put on a warning notice on the toilet door.
  10. My personal appendix nearly killed me (as in, I narrowly missed having it burst inside me) and I haven’t suffered for it ‘s absence since. I know - the plural of anecdote isn’t data - but it does seem to be an organ with significant downsides that we can happily live without. I liked the rest of your post though and would add that your comment about metabolic pathways could also apply to the genetic code Would alien genetic material be stored on a double-stranded polymer? Quite possibly - they’re relatively stable, convenient to read out and their macrostructure can be largely uncoupled from their microstructure* Would an alien genetic code be based on four monomers arranged in groups of three? Possibly - because that allows a reasonable number of coding units plus redundancy. Would an alien genetic code be based on DNA with the same codons encoding the same amino acids? Much less likely in my opinion. * DNA - double stranded, doesn’t much matter what the primary structure (nucleotide sequence) is - the secondary structure will be a double helix. RNA - single stranded, secondary structure very dependent on primary structure.
  11. The bit that got me scratching my head was, "Somehow I really doubt it wise to leave poo management systems up to idiotic AI when poo levels are more random than rocket engine firings..." I mean, I could understand being skeptical about our ability to build a fully automated waste management system, complete with automated replacement or repair of faulty or damaged components. Personally, I think that may be achievable, starting from the the kinds of system that you mentioned, and the question would be whether it would be more efficient to have a fully automated system, or to bring Joe (or Josephine - lets be equal opportunity here) the space plumber along to fix things. But I could understand the skepticism. What I can't understand is dismissing an automated (or AI system) out of hand because it wouldn't be able to cope with random poo levels, when a moment's thought would tell you that: a) a waste system which can't cope with said random levels is functionally useless - whether it's AI controlled or human controlled. We have waste systems that aren't functionally useless, therefore this most be a solvable problem; b) that we could maybe use those existing systems as a starting point for figuring out how to deal with the same problem aboard a spacecraft; c) that this is about the simplest part of the system to engineer anyway.
  12. No - we've merely eliminated one fanciful option (argon fixation). How you get from there to 'we're back at life as we know it', escapes me. And as for life being as optimized as it can be - life is as optimized as it has to be and no more. Take the human body for example. Our eyes aren't as sharp as a hawk's, we don't have the sense of smell that a dog has, our hearing isn't anywhere near as acute as an owl's (which can hear a mouse heartbeat from some ludicrous distance away). Our senses evidently aren't as optimized as they could be but equally evidently, they've proven to be good enough. Similarly, it's not hard to find downright poor design elements in human anatomy. The appendix. A combined eating and breathing system that can - and frequently does - go wrong, sometimes fatally so. Proximal (or even combined, in males) elimination and reproductive systems that can - and frequently does - lead to infections, particularly in females. For that matter, sticking the brain on the end of an obvious weak point like the neck isn't terribly optimized either. Evolution works with what it's got at the time and it doesn't work backwards. It can produce some amazing things but it can also produce some horrible kludges. But if those kludges are good enough for the job (i.e. there's no selection pressure to get rid of them), they will tend to stick around.
  13. A couple of thoughts. 1. Holding tanks are a thing and they would deal with unpredictable inputs. 2. Unless there’s a pressing need to reduce spacecraft mass in-flight, any solid waste could simply be stored. A spacecraft is a closed system so (roughly speaking) the quantity of food you bring for the journey is going to be processed into an equivalent mass of waste by journey’s end. Wasteroids not required. 3. At a very basic level, solid waste processing need not be terribly complicated. In principle that is - the details are always more complicated in practice and I agree that crew will almost certainly be needed for repairs and maintenance. Step 1. Vacuum dry the waste (finding a suitable high quality vacuum shouldn’t be hard aboard a spacecraft) to a) deodorise it, b) sterilise it and c) recover its water content as far as possible. I’m unsure about the water reclamation but apparently modern space toilets do vacuum drying for the first two reasons. Step 2. Grey water goes into the spacecraft water recycling system. Step 3. Dry matter can be stored. It won’t look terribly appealing but it won’t smell too bad and it’ll be sterile. The dry matter could be further processed depending on how fancy your spacecraft systems are and how much of a need there is for recycling. One conceptually simple option is simply to incinerate it, which is something that NASA is already looking at. Main product from incineration is carbon dioxide which can then be absorbed by hydroponically grown algae or similar bioremediation system. Edit. Apologies that last part was badly written. NASA is looking at incineration, the bit about the algae was my speculation.
  14. Toilets? How quaint. How very 21st century. Why - it's almost as if your passengers have never heard of NaniSan (nTM)!* No bigger than a standard medical suppository but packed full of proprietary NaniSan nanites which break down solid wastes into harmless, odorless gases, each NaniSan unit comes fitted with NaniRate (nTM) technology as standard, ensuring that gas buildup never reaches socially indelicate pressures. Popular add-ons include: Naniroma nanites. For that personalized, fresh smelling, feel-good scent production! Nanofusion cell. For pleasing warmth and proving that the sun does in fact shine out of your backside! Prismatic projector. An extension to the standard Nanofusion cell allowing the wearer to emit multihued lights. Yes - you too can poop actual rainbows! Boldly go where nobody has gone before with NaniSan! *How it works is otherwise irrelevant to the discussion.
  15. Ahhh, good stuff. I was going to pitch in with some thoughts but glad you figured things out. Sorry about the late reply - it’s been a busy couple of days,
  16. That would make sense to me. Having just re-read the Atomic Rocket's page, it mentions two Mylar discs (uncoated as far as I can tell and not ribbons as per my earlier post. ) with an air gap between them, each having an aluminium ring around their rim, which acts as a temporary electrode and electrical contact with the permanent electrodes on the magnetic nozzle. Each pulse unit consists of the aluminium rings, Mylar discs and fuel pellet in the middle. The whole thing is vaporised in the explosion and the reason why Mylar is used is to keep exhaust products as light as possible, hence exhaust velocity as high as possible. This is all from a secondary source though - I'm sure that the actual papers go into a lot more detail and probably consider other designs like coated Mylar as well.
  17. That sounds a lot like Mini-Mag Orion if I'm reading you right. Wikipedia article here, Atomic Rockets article on this page. A significant challenge with it appears to be the hellaciously high magnetic field required. The design shown on the Atomic Rockets page uses a separate nuclear reactor which powers up a whacking great bank of capacitors, which are discharged through Mylar ribbons to the fuel pellet. And yeah - Mylar is normally an insulator but 70 mega-amps laughs at such petty distinctions and makes Doc Brown turn green with envy.
  18. Medusa always struck me as being even crazier than Orion. I’m also assuming that forward facing windows aren’t going to be a big feature of any Medusa craft. ”Please do not stare at the nuclear detonations with other eye.”
  19. The old TRIGA design is interesting too - the hotter it gets, the slower it goes. So much so that I don't think it physically can melt down. Public safety announcement - I recommend searching for "TRIGA reactor" if you want to know more, and not "TRIGA", which is distinctly not safe for work.
  20. Possibly? I thought New Armstrong was intended to be their moon rocket (makes sense with that name), whilst Jarvis is intended to be an upgraded upper stage for New Glenn, to make it fully reusable? If you’ll excuse the comparison, New Armstrong would be to New Glenn as Starship is to Falcon 9. You could be right though - I’m just guessing.
  21. I guess it’s the first step for Blue Origin, with New Glenn being the second and New Armstrong the third, assuming that NA is still more than a twinkle in Jeff’s eye. Pretty much on-brand that they don’t seem to have considered the wider ramifications though.
  22. Oh - forgot to say. If and when Blue Origin start putting New Glenn together, I’ll be watching this thread for news as avidly as I watch the SpaceX thread for Starship news. Sadly, at the moment I find it hard to get excited about Blue (got the blues you could say). Ongoing lawsuits (not the GAO appeal I hasten to add) don’t help. Also… I just don’t find Bezos particularly sympathetic or inspiring. Musk has his faults for sure - and I’m not convinced I’d want him as a boss - but in general I like his straight-talking SpaceX persona. Bezos? Well he built the right shaped rocket.
  23. Guilty as charged, I’ve been an unabashed SpaceX fan since before RATSat. With that said, if it had been Mr Musk pulling that insecure ‘look at meee!’ nonsense with Mr Shatner today, I’d be hard at work digging out a snarky one-liner to call out SpaceX instead.
  24. “We often see the customer as a nuisance.”
  25. Ahhh, that makes more sense to me. Thanks. For some professions, I would contend that that inability to control the conduct of others does determine how far you can get in your profession but I'd also agree that that inability is moot unless you're prepared to put in the work to begin with. I'm thinking of most of the creative/entertainment industries. For every JK Rowling out there, there are plenty of published writers (including well known ones whose work you'd find on sale in bookstores and the like) who still can't make a decent living purely from their writing. And behind each those, there are dozens more writers who are struggling to even get that far. I'd imagine that works for most of the other creative industries. You can be working your tail off, doing all the right things and maybe even doing pretty well. Hitting the big time though, depends on a large enough portion of a generally fickle public deciding that your stuff is da bomb and forking over their hard earned cash for it. But I'm nitpicking now or, at the least, cherry-picking.
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