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DDE

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Everything posted by DDE

  1. @tater, I agree with @kerbiloid that this system is overdesigned for LES work alone. Basically, there's no point of having it around at all if you're not using it for propulsive landing. If you can recover a fairing, why not recover a fairing with some expended solid motors strapped to them?
  2. I was unaware that they've completely ditched the use of the trunk for fuel carriage.
  3. But if they are now opting for a parachute landing (what I'm taking from Musk's quote) why even have the engines?
  4. https://arstechnica.com/science/2017/07/spacex-appears-to-have-pulled-the-plug-on-its-red-dragon-plans/
  5. Highly unlikely, especially because the things most affected - computers and crews - would still be present and just as vulnerable. You need high thrust, thrust even VASIMR can't provide. Control drums to full reflector, stand by to engage atomic rocket thrust!
  6. Moon orbits are a menace, viciously unstable. The proposal was to put it at an Earth-Moon Lagrange point instead, but funding for such an op was pulled along with funding for Apollo 18-21. Other than that, there was no real obstacle. Lunokhod 2 kinda reached the dark side by operating very near the limb. https://www.xkcd.com/676/
  7. ...and then we arrive at the dual problem of single-point failure - how much of SpaceX philanthropy will endure should Musk take an accidental brick to the head? I also still suspect that no national government would take a serious colonization effort lying down; from a purely psychological perspective this is an unacceptable affront.
  8. Except the entry barriers are so freakishly high that nobody's willing to properly sink their teeth into it. For instance, creation of propellant ISRU infrastructure is likely costlier than using oversized vehicles for BLEO missions, given how few BLEO missions we launch and how few we will keep launching for the foreseeable future.
  9. http://astronautix.com/l/loxammonia.html Methane would also combust quite readily. Because I assumed that @sevenperforce's claims were solidly out of the solid-core reactor territory (pun not intended) in terms of core tmperature.
  10. @Casualnaut, I think the explanation may be much more mundane - the same graphics artist reused models from the old study. Wouldn't be the first time the people doing graphics for spiffy NASA presentations did something really stupid. Also, old North American Rockwell MEM lander projects featured nearly indistinguishable habitat, rover garage and return vehicle-carrying landers.
  11. Yeah, but whatever your lightbulb's operating temperature, hydrogen will always have better Isp. Although I do think the other remass materials are unjustly ignored given the reduced tankage size.
  12. A fair question. Some suggest nowhere because radiation encourages mutation, bootstrapping evolution. Protection against radiation is two-fold. In the long term, radiation causes cancer; high cell replacement tempo would only make the tumors grow faster, we need more enhanced DNA repair mechanisms instead. Refer to Deinococcus radiodurans ("Conan the Bacterium") and Thermococcus gammatolerans. Short-term acute exposure (Acute Radiation Syndrome) is much simpler and boils down to, indeed, quick replacement of dead cells, especially white blood cells, and handling the various free radicals produced by radiolysis; there's a reason it's billed under "toxicology". We're already seeing the first radiation protection meds, such as Ex-Rad (keep your Fallout jokes about you). Ultimately, pantropia, and radical adaptation of humans to whatever environment they are going to face, is just one solution to the problem of truly Earth-like planets not existing.
  13. Yet at the same time they talk about a Moon base... I'm afraid the SLS is to blame, not Mars, assuming this isn't a malicious maneuver to spread more pork.
  14. @jsisidore, a "suit" capable of reliably shielding against lethal amounts of gamma rays would look something like this, which they used to handle the ejected reactor fuel in Chernobyl: We're talking significant amounts of high-density armour plating all around. It's easier to do with a reactor because it's immobile and you can mix distance and directional shielding to further mitigate the thickness required. I know the Chernobyl liquidators also used lead breastplates, but these were widely considered utterly ineffective.
  15. Bam, here's a classic RL-10: And bam, here's it in Nertea's cryogenic rockets pack: They're generally used to reduce interstage length, not to change ISP dynamically, though.
  16. Reportedly, it's worse. Really, really worse. I hope my high school chemistry teacher is proud, because I didn't understand a thing.
  17. I imagine it was because of the added safety of a propellant that doesn't leak onto the deck. Inhibitants aren't difficult to produce - it takes just 0.6% of hydrofluoric acid. Hey, @kerbiloid, @Kryten, riddle me this: why does MIL-P-7254 specify IRFNA having NO2 content while Soviet AKs are specified as containing N2O4?
  18. Or more. However, a lot hinges on how light a nuke NK have or think they're going to have. That thing above had old electronics and a megaton-class payload. Does it really? I know US Type III IRFNA can be kept fuelled for decades, and I've never understood why there's all this incessant dancing around with Soviet АК-27И being loaded and unloaded between every bomber sortie.
  19. Well, what are our other options? No sense to fuel at launch site with NTO, cryogens are pretty easily detected (see link), and I still don't believe NK can manage ClF3. http://i.imgur.com/mN39W6R.gifv
  20. @Steel, you forgot my favourite. Is 14-legged killer squid found TWO MILES beneath Antarctica being weaponised by Putin?
  21. It's not a saying, it's the summary of this thread.
  22. I highly suspect that the need for terminal maneuverability will bring back liquid-fuelled missiles. A Sidewinder is basically a guided bullet after its solid motor burns out. At railgun velocities this is basically hopeless. Note how modern tanks are in many cases giving up sloped armour.
  23. Arguably it could be stretched; Soyuz is constrained by the peroxide reentry RCS. Expanded VA? All TKSs flew with standard-sized V, either capable of return or converted into instrument bays.
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