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About wumpus

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    Spacecraft Engineer
  1. It would still take a long time to create the spacecraft that can latch on to an asteroid and either bring the whole thing back or smelt it onsite. Also expect a year or more to get there and several years back. It would still have everything smelted and in ingots long before an enrichment reactor was in space and fueled for operation.
  2. The amount of hypergolics used in modern rockets are pretty small. On the other hand liquid oxygen has a tendency to turn everything it touches into an explosive (charcoal makes a high explosive). If you tried to launch a Proton out of KSC or Vandenburg I would expect a bit of an outcry, and I have trouble believing that the Russians are still launching those things. Of course, the usual "public panic" about toxic substances always ignores the dose. Ignore the dose and any toxicity report is mindless babel.
  3. My understanding is that there are plenty of nickel asteroids, and likely a platinum or iridium asteroid that can be found (those are typically suggested when mining asteroids). Certainly plenty of things heavier than aluminum (or whatever the heaviest bit of moonrock is), although you have to find asteroid. Anything flung into space via similar action would have large chunks of heavy materials. I wasn't thinking: smelting is trivial, especially compared to the energy source needed to move it around. Enrichment is the problem (assuming uranium is out there, it is still a big step up from nickel and iron), which is why I knew such a program would need one (fueled) nuclear reactor to enrich the material as it is mined and/or lifted to orbit. This method would be ideal for dealing with spent fuel rods (cooled down "correctly" or simply ejected and sent back to base). I wonder if it would be possible to ship up low level U238 and enrich in orbit/L2/wherever (and ignore the asteroids until they are mined for other reasons)? I'm guessing this would have all the same political issues, but it seems sad that such would stop a possible real interplanetary space program.
  4. 1.3 is non functional for me. Reverting to 1.2.2 is fine. I was away long enough that I couldn't use old saves in 1.2.2, but a new game fixed that. This seems pretty rare, but since I didn't want the language packs, once things worked in 1.2.2 I wasn't interested in fixing my 1.3 issues (although I'll likely try 1.3.1 to see if that works). Last I heard, RSS/RO works with 1.2.2 only. It is another reason I am happy on an earlier release.
  5. Any guesses on the availability of Uranium or Thorium in the asteroid belt (like a large rock that can be trivially smelted to one or the other)? You would still need roughly the fuel for at least one full burn and maybe more, but the idea would be no more fuel flights. This is more a "decades out" idea, but the politics seems to be going away not toward this type of thing. Since step 1: build an ion system to find an asteroid and bring it nearby (L2?) is more or less within modern tech (ignoring failures in latching onto comets, and no tests on asteroids) it might be a good place to start.
  6. Remember that each of these things has a high energy cost that is essentially stored in the target as its new phase. Most military lasers are only interested in blasting an arbitrarily small hole (however well they can focus*) on a fuel tank to destroy a missile. They have massive power and aren't remotely capable of digging a deep enough hole to cause a crater. I suspect nearly all craters made military action involved buried explosives (probably a shell going too far and burying itself, then immediately exploding. Or perhaps exploding sometime in the next century, see the "iron harvest"). Dropping a solid bullet is pretty inefficient, and only done to minimize blasts (I think the US Air Force has dropped guided blocks of concrete from B-52s to minimize nearby destruction). * make the pulse short enough and you don't need tracking. And anything in this power range is definitely pulsed.
  7. I'd expect that you can drink distilled water all through a shuttle-length mission (but you never would because you would be carrying drinking water and won't bother with scavenging spent exhaust or similar). A flight to Mars (and surface stay) would be a completely different matter and expect to use reverse-osmosis and distilling (the RO filters I've seen only filter half the water at most, cascading them only would go so far), and presumably add whatever minerals you would expect after all that.
  8. Ouch. And I just realized that Vandenburg* is a secure military facility, so I think you have to be a US citizen to be even considered to be on the grounds for a launch (I've joked that the only "weather" it gets is smog. Depending on the season that is probably close to the truth). Is there any "expect a rocket launch to be clear" season in Florida? Guiana Space Centre is possible (and presumably closest to Harvester's homeland, although I don't know where he lives now). Even in the winter (where freezing kerbalnauts might want to visit the tropics), I doubt you will get many to show up. * I think Wallops is Navy, but it is pretty low profile. If Orbital-ATK isn't launching to ISS, I don't think there is anything big going up there anymore.
  9. For higher TWR launches, it often helps (even more than usual) to angle the rocket in the VAB. Of course, control of this gets iffy so expect to either revert a lot or ignite your stages before releasing the launch clamps. One thing to remember is that people aren't always clear on how long a rocket maintains its launch TWR. A two stage rocket using a SRB first stage will gain TWR faster as it climbs than most rockets, while a three-stage (or more) rocket will typically gain TWR much more slowly than most two stage rockets. Adding hammers might wildly increase TWR, but that TWR won't last long. Typically it makes much more sense to use smaller engines (especially using less SRBs to wrap a first stage) than to throttle the engine or set SRBs to less thrust. Don't forget that KSP is an extremely flexible game (note the train enthusiasts on this site), you should consider being flexible in your rocket design. A tall, ungainly rocket that has great difficulty turning (read losses control the moment you turn in a thick atmosphere) might be well off taking an extended old-school trip straight up before turning. Such a design (assuming your noodle can handle it) would be more efficient with enough kickers wrapped around it for a TWR at least 2.0. It won't be efficient, but it might be one of the few ways to get it in orbit.
  10. Pick your (IRL) rocket launch. Said rocket launch schedule should ideally be as hard as possible, while still being a sufficiently high profile launch to draw a crowd. That said, the best I could likely swing in the foreseeable future is a Wallops launch, and that will never justify a kerbalcon. I still have my doubts about just how big a crowd KSP can draw on its own (it isn't like WoW or Quakecon), especially after the inevitable mission scrub (presumably the show would have to go on). [political speculation about Squad vs. customs scrubbed by poster. Which might be why it hasn't happened, considering this type of thing was their original business].
  11. Then by all means just print an F1 engine. It (both the original and printed edition) are proven tech. It certainly is more likely to get into orbit than any other suggestion so far. You might also want to look up some brand new technology called "forging". It makes metals stronger than if you simply melt bits of pieces together (although not quite needed for said printed F1 engine, it will still make for stronger metals of the same material/mass).
  12. I suspect it is more a matter of ejecting the core to avoid cooling issues. Running "exhaust mass" to cool the core is pretty disastrous for Isp, and I'm guessing it needs more cooling gas than the mass of the core. My guess is that any modern design that cools down the core for re-use is doing so to avoid the political issues of lifting up more "fuel rods". Turning a NERVA off is a pretty hard problem: ejecting the core is an easy solution.
  13. None of those examples are amatures. If you have access to that type of equipment, why don't you have access to a cheaper and much more common CNC milling machine to churn out turbopumps? Everything done professionally is possible, but it might have a NASA level price tag. I suspect that a lot depends on if you can merely increase the temperature of laser sintering and thus use appropriate materials at a much lower speed. This would still be pricy, but hopefully the cost would be somewhat linear. I would still be expecting to switch to turbopumps with this type of access.
  14. If they wanted to do this, I'd expect the time was during the design of the Tu-22 and the Tu-160 (supersonic heavy bombers). Don't expect them to provide a delta-v of much more than 500m/s (and you would need a total drag much less than the carrying vehicle to do this). I doubt that 500m/s is enough to justify all the extra constraints on the carried rocket. Remember who is building it. I wouldn't want to have to launch GTO satellites from Baikonur either (of course, why would you put GTO birds up with a craft that has wings?).
  15. It isn't even clear that fusion has any real advantages for spacecraft. Both produce high energy and emit plenty of radiation that require shielding. The biggest grip about fission is the waste products, and outer space is an ideal location for them (you can be reasonably sure they aren't going to bump into anyone else for the next few million years, at which point they will not longer radioactive). The real advantage that fusion has is that you can use (presumably) the direct output of fusion (by opening the magnetic containment), possibly without subjecting any other materials to its heat. This should give tremendous Isp, and doesn't even require breakeven fusion to do so (the energy could be produced by fission, for example). One reason to get excited about using nuclear thermal rockets is that presumably the James Webb telescope research paid for enough research on closed-loop cyrogenics. It needed helium, typically NTRs need hydrogen. Note that returning from Mars might not need such extreme Isp, and we might get away with low efficiency O2 or even CO2. Don't forget that if you want to travel to Mars, NASA already has cut most of the red tape for NTP by grandfathering research in the 1960s-1970s. This means that it is "good to go" on a bit less stringent and allows easier funding from Congress (although very little can stop a congresscritter from throwing pork in a direction he wants). I'd expect KSP players to be highly enthusiastic about NTRs, they are some of my favorite parts. The biggest catch is likely the cryogenics: it might not be reasonable to expect to have hydrogen for the return trip (having hydrogen for the braking/insertion burn requires considerable engineering. Nothing will stop the amount of leakage through all known mass over the stay on Mars, but it might be preferable to simply use what's left after the leakage to using CO2 found on Mars).