Steel

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About Steel

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  1. Oh yeah, it would be an immense achievement and a really interesting experimenter to see if it could actually be done. The other problem that you have, as @KerbMav pointed out, is that many primitive technologies are reliant on other living things (sticks from trees, fur/skin from animals) so you'd actually have to reinvent some primitive technologies in light of the fact that, for example, there are no sticks on Mars with which to make an axe, nor are there any trees to cut down to build furniture and equipment (a LOT of humanity's tools are wood based). The other Major thing is that you can't light a fire or the Moon/Mars, so how can you get metals from ore? In theory, yes. As long as you can synthesise/grow trees to make rubber for seals and things, and you have a sufficiently advanced workshop to make things like high quality canvas for a hab. The big thing is the electronics, silicon is tricky stuff, so making solid-state electronics would be difficult unless you had a full-scale silicon foundry.
  2. Unless you're planning on recreating the entire history of human tool use in a vastly accelerated time period (i.e starting off with stone tools and gradually working your way up to precision CNC machines and silicon foundries for electronics) then no. All the technology we have now is entirely reliant on the technology that preceded it, and this goes all the way back to the beginning. Thus, if you take away everything, you have to start right back from the beginning and build up to get to today's technology.
  3. I suspect that's the exhaust from the pre-burner that they're using as a vernier.
  4. There's a book: Space Sailing by Jerome L. Wright that might be worth checking out on the subject. It is very much in a textbook style, so plenty of calculations and things.
  5. Luckly, the public doesn't know what hypergolics are, so they have no problem with them. If knowledge of what they actually are was a common as "knowledge" (I use the term loosely) about nuclear reactors, there probably wouldn't have been silos full of hypergolic nuclear missiles all over the US a few decades ago. Having said that, the effects of a nuclear accident will last considerably longer (potentially hundreds of years) as opposed to a hypergolic accident (maybe a few days). It also depends hugely on the size of the reactor in question, obviously a probe sized reactor like the ones we have currently launched are not especially dangerous even if they leaked, as long as it was somewhere remote and not in mid-air. The worst case scenario with any nuclear reactor is that it bursts and breaks up in a launch accident and spreads radioactive material over a wide area. The environmental damage to humans would be much less over the sea near the Cape rather than at Baikonur, but you'd still end up evacuating all the beaches for a hundred miles in case radioactive material started to wash up on the shore. It would only take one bad accident to end the whole thing indefinitely over "safety concerns". The problem with public perception is that it very rarely has any correlation with the facts about whatever is in question. You can design the safest nuclear reactor possible, but one ill-informed celebrity shouting "CHERNOBYL!!!?!?!11" on social media will scare enough people to make it a PR nightmare (or one stupid clickbait article in a dodgy tabloid, along the lines of "NASA rockets have NUCLEAR BOMB ONBOARD, even a small accident could be THE END OF DAYS"). It's the same sort of situation as with global warming, you can't persuade people with facts if the facts don't fit into their personal world views. There are actually studies (I'll try to find a link later) that conclude that if you try to persuade a non-believer that climate change does exist by showing them facts, you're actually more likely to cement their denial than change their mind. The TL;DR from all this is that the public in general don't care how safe something actually is, just how safe they think it probably is.
  6. It is a really good book, would thoroughly recommend to anyone who hasn't read it yet. If you go through some of the forum posts about rockets and rocket fuels it's cited frequently by quite a few members of this forum.
  7. No, a laser is ever going to leave a crater (unless you class a hole caused by the laser melting something a crater) or a mini explosion, unless the ground is made of some highly volatile substance that explodes when heated. Traditional weapons (i.e projectile weapons) use kinetic energy to cause damage, thus the impact craters and people being thrown backwards when they're hit. Lasers are very good at transferring energy to a target, however a laser beam (pulsed or continuous) has very little kinetic energy. This means you wouldn't be thrown backwards by being hit, and you wouldn't get the impact marks that you see from projectile weapons.
  8. Just on the safety side of things, a quick skim though the above CASA documentation highlighted the following passage: So if you're planning on making home-made rocket motors, you'll have to get government approval first, otherwise you're technically making illegal explosive devices. By the look of it the only rocket motors you're allowed to use in Australia without prior government approval are kit motors. Also, if you want to launch anything that weighs over 1.5kg, is powered by anything more powerful that an H-class (320 Ns impulse, which is pretty big for a model) motor or has a metal construction, it's classed as a high-powered rocket, which means you'd have to be certified. Finally, there may be additional state regulations to look out for in addition to these CASA ones.
  9. In short, they're not more effective. It's more a public perception issue, most people don't like looking at giant solar farms by the side of the road so are resistant to having them built, where as they're less resistant to having them in the road.
  10. This issue here is that rockets are not laterally stable enough to withstand the aerodynamic forces of a glide - you can see it in the footage of some rocket failures, once it deviates more that 10 or 20 degrees away from it's velocity vector it will just break up. Thus, you either end up going for the SpaceX route, or you end up having to strengthen the stage hugely, adding a lot of dead-weight, in order for it to be able to glide.
  11. A little off topic, but even today we can't do a high fidelity simulation of full aircraft in any sort of reasonable time. Modern airliners, in all their myriad complexity, still only have really high-quality CFD done on sensitive aerodynamic areas of the wings, they only do those small sections at a time, and even then only at certain flight conditions. Aerodynamics are pretty complicated as it turns out!
  12. Be careful here, being able to conceive a fluid with these properties is very different to being able to engineer a fluid with those properties in the real-world. If John D. Clark has taught me anything in Ignition!, it's that additives that you think will help a fuel more often than not have the opposite effect. Let's not pretend this is a shining beacon of a demonstration that this technology works. The launch record of the GIRD-9 [1] - which is the hybrid version of the engine - was 4 failures and one partial success where the rocket flew 400m before the engine failed. After that they seem to have completely abandoned the concept. Not to mention that the geometry that was used is totally different from what's been proposed here, we can pretty much say that it's a completely untried concept. All we can really take from the Russian engine is that the propellants burn when put together and heated. [1] http://www.astronautix.com/g/gird-09.html)
  13. I've found the problem I'm afraid. Your calculations are out by a factor of 1000. 81 tons (i.e 81,000 kg) of air being cooled 630 K will take 51 GJ, not MJ (1x103 . 81x103 . 630 = 5.1x1010), which means your heat pumps will need require almost a terajoule at your quoted efficiency. This is why most of the concepts for this that I'd seen were LH2 based I guess, heat pumps just don't work well enough.
  14. Tungsten ice, otherwise known as Tungsten?