wumpus

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About wumpus

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    Spacecraft Engineer
  1. SpaceX Discussion Thread

    I suspect that "vertical drag" is more the issue than lift: getting any sort of glide ratio would be tremendous help. The shuttle had a glide ratio of 4:1 and was considered a falling brick. KSP vertical landing works well after gliding in at 1:1, I wonder if that is close to realistic. I wonder how hard it would be to make an elliptical rocket (probably manufacturing costs would be painful, especially if *anything* gets done on a lathe). One question I have about spacex plans is about landing this (or similar) on Mars (or the Moon if NASA is paying). Elon talks about "vertical launch and land" but NASA tends to avoid such things. The LEM (or correctly "LM") used two separate rocket engines, allowing the landing rockets to be damaged during landing. There was a pitch for a rocket-propelled lunar vehicle (the rover made infinitely more sense), that required a "launch blanket" placed underneath it to avoid damage from moondust. Curiosity was dropped by a "skyhook"that kept the rockets from covering Curiosity with dust. All these show that NASA really doesn't like landing on uncontrolled surfaces (completely different from the platforms that Spacex lands on now) and hasn't changed their opinion with plenty of experience. I've heard there are explanations for why they think they can launch with landing rockets on Mars, but I wonder if any actual landing engineers are convinced.
  2. Should We Launch a Kid to Space?

    The only reason the heat shield was ever in danger was that it was exposed during launch. This doesn't happen with capsules. Also the Columbia's heat shield was so large it was built with delicate tiles: something that was never necessary with capsules. The spaceplane design directly doomed Columbia by exposing the heatshield and doomed Challenger's crew by having the crew cabin an integral part of the oversized cargo bay: every other [capsule based] rocket has had a launch abort system, but the Shuttle was too massive for one (the Shuttle had plenty of abort modes, nearly all with zero chance for survival). How could falling debris during launch possibly damage a capsule's heat shield?
  3. Should We Launch a Kid to Space?

    The Columbia was destroyed thanks to failed/damaged/knocked off heat protection, and thanks to the spaceplane configuration that protection was vulnerable. I don't see how you can claim it wasn't due to heat.
  4. SpaceX Discussion Thread

    I wonder just how long it would take to justify building an aluminum plant (or other chemical process where the standard procedure uses a lot of electricity). From a chemical production view, cracking water for hydrogen (and oxygen) is pretty silly and there are certainly plenty of other chemical processes that require electricity. Aluminum is pretty obvious, the stuff is called "frozen electricity" for a reason. Basically look at what chemicals are being produced near Niagara Falls and see what has low startup costs. Also how much of Texas? There are three grids in the US: East, West, and Texas. I'm guessing it is too far to run a DC line (avoiding grid issues) to Louisiana and the chemical plants there. No idea what this has to do with Spacex (Tesla bought Solar City, not Spacex).
  5. Should We Launch a Kid to Space?

    Eating high g-forces in the lower temperature parts of the atmosphere will be safer. A lifting spaceplane will be slow and have far higher heating thanks to the bits of the atmosphere you slow down in. So far, Columbia is the only spacecraft lost in re-entry (Soyuez 1 had a failed parachute) and isn't the method I would recommend for kids. Typically you will get g-forces less bad than a roller coaster (bad Soyuez landings excepted). Beats the dangers of spaceplane heating.
  6. Haumea has rings

    So if you colonize Haumea, does it bring wealth (and arbitrarily prolonged life*)? * I'm not sure the 7 had that effect on the dwarves, but they apparently brought wealth with little side effects. Sauron wasn't happy with the results.
  7. Oddly enough, digital signal processing (basically anything computing a fourier* or related transform) will see effects rather similar to Hiesenburg's uncertainty principle. I *think* that they are related primarily due to underlying math behind waves in general, but really don't have the math to tell. Basically it all comes out under "windowing theory". * image, audio, and video compression often use discrete cosine transforms, a related transform. I also took an undergraduate class on DSP in the early 90s which could now be almost completely replaced with the phrase "just take a 1k FFT...".
  8. If it is in the same spot every time, you can assume that variable factors won't effect it. This pretty much leaves out weather patterns. Fluid dynamics, hill geometry are certainly factors. I suppose that if there is a sufficiently prevailing wind, that might matter (after taking into account any local aerodynamics).
  9. Mun flyby in interplanetary missions

    While I watched the video, I can't remember the reasoning. I'm guessing that you won't get much deflection angle (and thus little slingshot effect) once you have enough delta-v (less slingshot effect) to get to Duna/Eve (and it only gets worse by going further). This gets compounded as without the deflection angle you are much more limited to when you can leave, which means you lose more from changing your launch window than you gain from the slingshot. While I find it a lot easier to use the Mun to slow down from Minmus, I suspect that the math doesn't work out for Aerocapture from outside of Kerlbalsoi. But it still might be worth trying (assuming you have the delta-v to correct from the Mun).
  10. NASA SLS/Orion/DSG/DST

    R7, Redstone, and Atlas were all built with suborbital nuclear warheads in mind. Mercury and Vostok were presumably built with their respective capsules in mind (based on rockets designed as ICBMs). While it would be a wild exaggeration to claim that the Shuttle was "built with keyhole in mind", the Shuttles dimensions, cargo capacity and return capacity were dictated by the spy satellite. Google (and lost bookmarks) have let me down, but from memory one of the "rules of rocketry" is "any mission involving a new launch method becomes a launch project". Rockets built for specific missions are budget breakers and can only be expected for "milestone" missions.
  11. Wich real life rockets do you think look kerbal

    There's also all the Orbital rockets. Considering that Orbital's business has been to refurbish surplus ICBMs into orbital launch vehicles, there is plenty of kerbal "put rockets together like LEGOs" designs. I suppose the Antares rocket might be less Kerbal in that it places a solid stage above a liquid first stage (the liquid first stage isn't surplus ICBM, but was originally surplus N1).
  12. There's only so many ways to say "the laws of physics say so". Admittedly, while the theory behind "speed of causality" largely depends on veneration of Maxwell's Equations*, experimental results keep pounding away that it really works that way. * this made all kinds of sense when Special Relativity was published, but hasn't really been the supreme work of physics for quite some time. Nevertheless, its complete indifference to frame of reference has been shown to be true even while quantum level electrodynamics had to be rewritten a number of times.
  13. Actually the "eternal September" started in September 1993 (mostly a coincidence, the name comes from the similarity to the wave of freshman discovering the internet each September), while "All Good Things" (last TNG episodes) aired May 1994. Altavista would start the year after. So the public was already discovering this "internet" thing, although plenty may have thought it part of AOL.
  14. They [the dynamite] aren't required. Engineering installs them (and cuts out the seat belts) to keep line officers from requiring too much abuse of the ship. Either the Line officers haven't realized it, or they simply can't stop the continual insertion of dynamite included parts in the ship. By TNG times, the tradition is so ingrained it might as well be required. I'm pretty sure TNG was over before google existed (although maybe alta-vista popped it up and they stopped).
  15. Thoughts on a Gaming Controller for KSP?

    I'd assume docking. Whenever docking, I'm always wondering why I'm not using a controller. I'd assume that a joystick would work best for normal flight. If so, that was odd timing. Consoles still had a bit of an advantage thanks to RISC architecture and directx overhead (and general microsoft kludgyness in directx). But I guess there isn't much point in "console shaming" now that it generally takes a fps/detail hit to play on console.