Terwin

I believe you need to use an engineer to 'perform maintenance' to transfer fuel from a nuclear fuel container into a reactor and transfer depleted fuel from a reactor to a nuclear waste container. Automatic maintenance can also perform this function(but I think the engineer is still needed)

Considering the speed of bureaucracy, this might well be a prompt response to IFT-1

Anywhere you transition from flesh to bone/chitin is a possible vector of infection. Much like our gums need regular maintenance to avoid infections that lead to tooth loss, even though they are in an environment that is hostile to most microbes. Why make the hands out of chitin? Also, a small tube on the back of the arm should be less prone to clogging/obstruction(sort of like a urethra and just as prone to infection if not kept clean). 70' seems unlikely, even 20' seemed pretty optimistic and you still need to hit the same spot with both squirts, so anything more than 5-10' is probably useless unless a majority of an individuals caloric intake is dedicated to producing the liquids along with a large internal reservoir to build up enough to have a decent chance to hit farther away. (How far away can you spit and hit a quarter laying on the ground, consistently enough to be useful when you only get 1 try per day? Now try the same trick with your urethra, but you only get 0.5-1ml per day and you need to hit the same quarter-sized patch with both arms. A palm-vent would be even worse as even finger-placenent would affect the stream direction.) Also, humans are expert throwers, so don't pretend your theoretical species is just really better at rage, as humans are already fairly optimized at that. Tldr; a bi-reactant biological ranged weapon, even if feasible to make, would be terrible to use and probably not have a greater useful range than an extendable club/baton or a baseball bat.

If the compression wave hit the entire surface at the same time, that seems like it would make the impact have a shorter, sharper duration. Considering that you are already needing a shock-absorber, that does not seem like a good change. If the explosion is off center, having curved surfaces could also introduce lateral jiggle, potentially causing severe wear or even destruction of the shock-absorbing mechanic. A flat surface where all forces striking and rebounding from it should only push you froward seems like a safer bet. On the other hand, if you are close enough that you could cover a larger proportion of the shock-wave with less material by curving it, then it may be worth the extra engineering.

That is called burning and it turns the diamond into CO2. Once the diamond is lit, it can keep burning even at very low temps, even submerged in liquid O2. Methane is great because it is 40% 25% hydrogen by weight. (Water is only 20% 11% hydrogen by weight)(Forgot neutrons) Pure hydrogen is much better for the isp but ts very low density and hard to handle . Adding anything to it just before burning can only hurt isp.

The storage requirements for metallic hydrogen make it a non-starter for rockets. 90% of your launch mas would be fuel tank, limiting you to short, low-velocity hops. There was a theory that metallic hydrogen had a metastable island that could make it almost shelf-storable and remove that constraint, but it did not work when tested. Methane is used because it is a much more dense and easier to handle holder of hydrogen. It would be silly to turn hydrogen into methane for rocket fuel unless you planned to store it for a while. Diamond melts around 4500c and hydrogen evaporates at -253c, so you are not combining those in any direct way. Metallic hydrogen converting to hydrogen gas(H2) releases much more energy than burning it does, and leaves you with pure hydrogen reaction mass, giving a theoretical isp of 1700. Adding anything to it will only reduce that number.

Well, depending on you definition, might have been Ikaros in May of 2010(first solar sail)

Unless you are shipping tons of rare resources off-world, you cannot 'run out of' resources, you can run out of conveniently available or cost-effective to harvest resources, but you cannot run out of the resources themselves. (Volatiles like oil may need to be reconstituted, but that is still an option) Worst case scenario is resources are more or less evenly distributed and we need to harvest them similar to how we harvest 'rate earth minerals' now(they are not rare, they just do not occur in usefully concentrated forms)

In capitalism Entrepreneurs create jobs. More entrepreneurs = more jobs. So long as there is enough capital made available to entrepreneurs, there is no limit to the number of potential jobs. Also, productive labor produces capital, allowing for the exponential growth of wealth we have seen in the last few hundred years. From 1ad to 1000 ad, india' gdp per capita stayed arout $450(1990's dollars), while china grew from $450 to $466. Roman Italy was ~$800 in 1ad By 1500ad India grew to $550, and china to $600, with Italy still at the top with $1100(this was the Renaissance with Michelangelo and da Vinci) In 1750, 1st world gnp per cap was $804(still 1990 $), but by 1990 that ballooned to 15,413. A 10x increase over ~250 years when the prior wealth levels had been stable for ~1700 years. I attribute this growth to the growth of industry, ie capitol. Population was also only growing very slowly. 190M in 200ad, 275M in 1000ad, 610M in 1700ad, 1B in 1804, 2B in 1927, 3B in 1960, etc More people means more jobs and more wealth per person(on average) because people performing productive work creates wealth. Not to mention that someone living in public housing today has luxuries that were simply unavailable, even to kings, a few hundred years ago.

While it may make sense to supplement the heating with microwaves if your nozzle can handle higher temps than your reactor, converting from heat to electricity to microwaves to heat cannot be as efficient as just conducting the heat directly. So heating up your reaction mass to the reactor temp while simultaneously using it to cool the reactor is much more efficient.

It makes sense that being much closer to success would mean fewer things to address, and as there was no real additional hazard area for this flight, the faa is probably not terribly concerned about the mishap, so long as there is a plan to do better.

Straight lines are used because they are easier to draw and visualize. Actually the lense will bend all light that hits it. This is part of why you generally have camera lenses in an opaque black tube: to minimize extraneous light that could interfere or obscure part or all of the image . Much like friction-less inclines, those lines are a simplification to provide a clearer explanation, not a fully accurate reflection of reality.

I had hoped that following the flight path all the way to the end might not count as a mishap, but at least the additional hazard should be close to zero. I expect that most of the mitigation is to improve control, which SpaceX wants to do anyway.

Not at all, a rocket is a controlled conflagration(just like a lighter, gas stove, gas water heater, fire place, coal power plant, etc.). There is research into continuous detonation engines, but it is very difficult to maintain the continuous detonation(but would greatly increase ISP) The reaction mass carries away the heat, and generating the heat to heat up the reaction mass is the entire reason you have the antimatter on board, this is a benefit, not a cost. Orion has much more of a heat problem than a rocket because the pusher plate absorbs some of the heat and you have no productive way to get rid of that heat, more over, the further you get form the explosion(and the heat) the worse you thrust and isp get. The best option to manage for the heat for Orion that I have seen is to coat your pusher pate with some sort of liquid, cutting down on how much of your pusher plate gets vaporized with each bomb, but this is only a partial option as running the Orion continuously will still heat up the plate until it finally gets soft enough to get splattered by the next bomb. Nope, Unless you are using some sub-optimal configuration to avoid destroying your launch mount, you always use the same bomb, the largest you can safely use for propulsion. This maximum safe size may go down as your pusher plate gets eroded, but it will never go up. (moving the bomb further away has the same effect as using a smaller bomb, so using a larger bomb further away just wastes materials) Sort of, as you will have the non-charged particles wearing away at your nozzle hardware, giving you the life-span limitations of Orion, combined with the massive energy requirements of an ion engine because you need to generate the magnetic fields to push away the charged particles(but much less efficient than an ion engine because the particles are much further way from the field), giving you the combined draw-backs of Orion and ion engines.

I would appreciate you explaining the physics of this to me, because everything I know about rocketry says that antimatter pulse is stupidly wasteful and inefficient compared to thermal antimatter rocketry, for both ISP and TWR. Are you assuming that pulse propulsion does not need reaction mass? Nuclear pulse requires a tungsten plug to work as the reaction mass that hits the pusher-plate, and antimatter pulse would also require a large amount of reaction mass to throw against the pusher-plate, much of which would miss and be wasted, along with > 90% of the energy in the antimatter explosion, much like nuclear pulse. The only difference is that a nuculear pulse is ~ 1,000,000 times as energy dense as chemical reactions, letting you get 100 times the push with only 0.1% of the efficiency. (antimatter pulse does *not* have this advantage over antimatter thermal, because they both have the same energy density)

Um, no. Consider a regeneratively cooled rocket nozzle. It is able to withstand great temperatures and a lot of well-controlled pressure coming in an easy to predict way. Now design something that can withstand highly variable temperatures and pressures with the ability to change rapidly, both in intensity and direction, with much tighter weight restrictions because it can only harness a fraction of the energy it is being battered with, as most of it is pushing the wrong way. Note: temperatures and pressures can get much higher than the nozzle interacts with. You are suggesting that it is easier to design and build a mobile structure to resist tornadoes than it is to build a stationary, reinforced wind-break that only needs to survive 1% of the wind-speed of a tornado, from one direction. For the same energy release, a rocket is always better than external combustion. Always. Thermal antimatter will always be more efficient in both TWR and ISP than any sort of external combustion antimatter. * If your materials can withstand a temperature of X, then running your thermal antimatter at (x-safety margin) will always equal or beat being far enough away form an explosion so that it cools down to (x-safety margin) as you will, at best, get the same result, but only by benefitting from a small fraction of your fuel and reaction mass. * Anything you can do to get a better result from your am-pusher plate, can also be done to get the same benefits(or more) in a thermal rocket. * A rocket gets to benefit from roughly 100% of the pressure from the heated reaction mass, while any sort of pusher-plate will, at best, get less than half of the pressure from an external combustion event(because to get any more, it would need to be inside your reaction chamber, even 50% would require half of the event be inside of a chamber of some sort, but much of that would be laterally focused and thus lost), usually only a small fraction of 1% because being any closer means your vessel gets vaporized by the explosion if you make it large enough to be a useful external reaction.

It seems reasonable that SpaceX may include starlinks as payload on attempts 4+ They may wait until 5, but loading 4 seems plausible

External combustion is the *least* efficient option. Not even modern trains use external combustion any more. External combustion is only viable if there is no other option. Thermal antimatter is entirely doable as a rocket, so external antimatter reactions can never be within an order of magnitude of the most efficient option. Not unless we learn something that would re-write every physics textbook from jr high on up

I am guessing that the faa only cares if the hazard is increased by a given action, or if something done without informing them The fact that a booster splashing down in an exclusion zone might only be destroyed by water turbulence instead of a hard splash-down(or disintegrating as it falls), does not seem like it would be of interest unless it might stay afloat for an extended period.(Probably why they need a guy with a rifle on-hand for starship, In case it does not sink on its own) The faa might not even care to be informed of the type of splash-down, so long as it is in the designated area.(Such as landing on an unmanned barge as opposed to slamming into the waves, letting the owner risk non-human assets as much as they want, so long as it goes where they were told it would go)

I remember reading that if you used antimatter as the energy source for your rocket, you could use the same reaction mass tank(possibly water?) regardless of your destination, you just use a higher energy mix by adding a higher proportion of antimatter to energies your reaction mass before you shoot it through the nozzle. And no, antimatter is not your reaction mass, it serves the same function as the nuclear reactor in a Nerva engine, just (presumably) lighter

I thought that was just having a conductive path through the silver of the fillings that was the right length to pick up radio waves of the right frequency (possibly conducting it to the nerve for lots of fun) So both radio and solar storms would just add an electric charge to part of the tooth. Solar storms received by radios sound like louder static if I recall correctly.

Sort of like the Spanish inquisition? If you disagree with our morals we 'put you to the question '? How do you have a character based solution to self-published phone recordings of a newsworthy event when the citizen journalist has no history, just luck? Also, how do you identity which of the conflicting accounts should be considered truthful or criminal when they primarily differ in definition and framing? How about the same source video cut and framed by two different providers, giving widely different understanding of the situation based on framing? We know that governments will eagerly abuse such authority, and any other organization will likely start out corrupted and favor one set of views over others Multiple independent organizations gives us the current splintered view of 'truth' based on your source. I see lots of issues, but not a lot of solutions, especially considering our current status and lack of agreement on things as simple and basic as gender.

Adding insulation on the inside is probably cheaper and can be just as effective, if not more effective if you need it. Structural components are very expensive and require maintenance, but insulation is cheap and only requires care if it gets wet in most cases.

Even assuming that they are not some sort of insect that communicates through pheromones, and they have the capacity to perceive your attempts to communicate as such, why would you depend on the intellectual and computational capacity of a presumably more primitive society to decide and understand your message which presumably has a finite and thus limited body to work on (and no doubt includes ideas for which they do not even have words) As opposed to having as much time and computational capacity as you can cram on your ship to decide the more primitive words and ideas of the culture you intend to contact? Someone very lazy could do as you describe, but it would not make a very good impression, and may only be worked on by crazies if everyone else thinks it is a hoax

This is a reaction less drive, so inverting it seems like it would reverse the direction of thrust. Then again this is a magic drive, so if you want it to, inverting the thrust could cause daisies to sprout from the control console.