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    Spacecraft Engineer

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  1. Nope. Never heard. First impression is they are trying to commercialize the 70s' USAF Minuteman Air Mobility Feasibility test. They talk about established technology and the rocket looks a bit like a Minuteman, especially in the lower stages. Commercially used as a launch vehicle under names Taurus and Minotaur-C. In fact the shape is very reminiscent of the M-C, although at 27,9m that needs just a bit of work to fit in a C-17's 27m hold. All in all I fail to see much innovation there. Despite what they say on their pretty average corporation style web page. Let's see some hardware before getting enthusiastic.
  2. Certainly this. Note how the bottom of the fins aligns with the chine alongside the hull. This chined cross section is similar to the Type 212CD, where it is intended to direct active sonar echoes away from the emitter. See this article for a picture and details: https://www.navalnews.com/naval-news/2021/09/radical-new-stealth-submarine-type-212cd-will-be-much-larger/
  3. Cork also has the advantage of not melting or sublimating on its own. Temperature control in a vacuum chamber (remember, spin launch accelerates in a vacuum) isn't exactly off the shelf technology either, I believe.
  4. I'll see your road train and raise you a rack railway: The problem is not power, it is friction. Even the stickiest rubber tires will slip on steep enough a gradient. With more power you'll just burn through them quicker. The answer is a rack and pinion. Friction is not an issue when the force is transmitted from tooth to tooth, against rather than across their surfaces.
  5. This does sound kinda like the nuclear salt water rocket. Here's the obligatory Atomic Rockets link: http://www.projectrho.com/public_html/rocket/enginelist2.php#nswr
  6. Spinning up the spacecraft is not unavoidable. It does require active measures to prevent though. Rockets or reaction wheels can counter spin. A massive reaction wheel accelerating opposite way from the shot should work, definitely would work well enough for a fictional setting. After release set up the next shot rotating the other way and counter the spin by decelerating the now very fast rotating reaction wheel. Oh and don't plan on maneuvering while that wheel is going - gyroscopic forces from something massive enough will make turning quite impossible without massive propellant expenditure. But your aim is still limited to intercept points near the plane of rotation. Missiles' maneuvering ability and distance to intercept determine how far off plane you can target. Probably not practical for low orbit ship-to-ship scenarios unless you limit your vehicles to very slow accelerations. If time to spin up a shot is much shorter than time to perform a meaningful plane change then it could work. Interplanetary distances, where travel mostly happens near the ecliptic, could also work. And a huge constellation of orbital defence satellites around a fortified planet could have shots ready on so many planes pretty much any approach can be targeted. They cannot concentrate their fire though. Tether behaviour after release is also a concern. It isn't really a viable weapon if, after release, the tether proceeds to wrap itself around your ship and crush it like a soda can. It may be necessary to release the tether into the void too. That will increase the cost of a shot and add a danger to navigation. Latter can become a plot device though, if a random ship damaging event is needed.
  7. Dunno about UK, but let me share a traditional recipe for boiled duck. 1. Put the duck in a kettle and fill with water. Boil for 1 hour. Throw away the water. 2. Fill kettle of duck with milk. Boil for 1 hour. Throw away the milk. 3. Fill kettle of duck with vodka. Boil for 1 hour. Throw away the duck. 4. Ready!
  8. Your meat contains both sodium (from salt, or sodium chloride) and potassium (from saltpeter, or potassium nitrate). Their electrode potentials are about -2.71V for sodium and -2.92V for potassium. The difference is approximately 200mV, which is what you measured. Aluminum goes up to -1.66V so theoretically you could see well over a volt with the wrapper. Not knowing how the meat was prepared, how you had it on the wrapper and which points exactly you measured makes it impossible to say what is in reality happening. Stuff like whether the salt and saltpeter were mixed together or if one side of the meat was treated with salt and the other with saltpeter can make a difference.
  9. Well now I'm right back at before asking anything - but turns out that's where the world is too. Oh how I did... I had a toy bow, and when I grew bored with it I fixed it to a length of panel to make a crossbow. Very simple one, just a notch across the groove to hold the string and a lever, pressed with my thumb, to lift the string to fire. Also far more dangerous stuff - amazingly I still have all my fingers - that I won't go into here where we have impressionable young minds reading. So, there really isn't any alloy that could be considered "common cutlery metal." Things that have a variation of the common "stainless steel" markings on them probably have above average chance of being forgeable. Adding heat helps even if you can't get the metal to glow. Ominous.... Oh I have my name on several lists for far more sinister stuff (like being a person of my gender and age in a country that has conscription). I have always had this tendency to think about stuff that have zero practical effect on daily life. Just this asking of questions is a new development - previously I just dove into wikipedia (and books before that) trying to make head or tails out of stuff I could not comprehend.
  10. Thanks both for your input, although actually I was not worried about getting a sharp edge, but whether one could hammer the spoon flat before the metal shatters from work hardening (or whatever, my metallurgy skills stop at twisting a wire until it breaks). As a spoon shaped arrowhead isn't very good for straight flight. Although, should shattering be a concern one could probably start from a soup spoon and find a big enough flat-ish piece from whatever bits remain after. But getting any arrowhead was not where my curiosity went morbid. From where I sit right now I can see multiple square meters of suitable sheet metal to form into makeshift arrowheads. It was specifically the "...from a spoon" part that my mind would not lay to rest... There's probably another question right there, one concerning the state of my mind...
  11. How amenable would common utensil steel be towards cold forging? e.g. hammering a teaspoon flat for use as a makeshift arrowhead. You may consider the suitability of a common household hammer at your discretion, too. Asking to satiate a morbid curiosity.
  12. Possibly because to increase sensitivity the GoPro is somewhat sensitive to near visible infrared light, and the plume happens to be quite bright at those wavelengths. I know this is very common with smartphone cameras; that's the reason you can see a remote control led light up bright in a phone camera but not with your eyes.
  13. That seems so easy and obvious, doesn't it? Until you start to dig into the details, that is. The problematic detail is that you want the space end of your elevator to be on the stationary orbit to facilitate docking and undocking. Because the Moon rotates so slowly, it does not have a stationary orbit. You would have to build the elevator taller than the Moon's Hill sphere is, or in other words, higher up than where things stop orbiting the Moon and start orbiting the Earth. Literally the Earth would rip the top of the elevator away. Well, maybe build the elevator just to the edge of the Hill sphere and gently push the cargo towards Earth from there? That should work, but in essence you have then just built a very long and slow railgun. Far cheaper to build it smaller but stronger.
  14. And you will experience days/months worth of radiation in minutes/days. In other words, a trip that in real time might've upped your life long cancer risk by a percent or two could become fatal. Maybe not instantaneously, but being dead in 30 days still sucks. Instant death is also an option if you turn the time warp up to 11.
  15. So... narco cruise missiles, or maybe call them narco drones, as a logical next step from the low flying GA planes of 80s lore? (Btw. do they still fly those planes or have subs taken over fully?) A motorcycle engine tuned for fuel efficiency, fixed pitch propeller, glass fiber body and wings, some generally available electronics and FOSS flight software. Next generation mix some graphite or iron dust into the resin for a makeshift RAM that is just as likely to make the thing glow like the sun on radar. Third gen someone rigs up a test device from an old radar speed gun and they get the RAM to actually reduce the signature a little. Fourth gen they buy help from escaped russian engineers and the designs start to look a lot more professional... How would you rate this scenario on a scale from utter nonsense to a Tom Clancy novel?
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