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Everything posted by tomf

  1. I know what they mean, but it just occurred to me that if you were to ask someone in the 60 which would happen first, routine landing of rocket first stages or almost everyone on earth carrying a device that would enable them to video call anyone else on earth they would have thought the rocket thing more likely Weird how perceptions change .
  2. Just to confirm my intuition I just did a test in ksp. I built a simple two stage rocket with about 5000 m/s delta v with fairly low twr. First launch was directly upwards and it arrived at the edge of kerbin's soi with a speed of 856m/s. The second launch did a conventional gravity turn before burning parallel to the surface. That one arrived at the soi with 2000m/s So it seems clear that the gravity losses for burning directly up are pretty substantial.
  3. Not saying it would be easy but antimatter at 4k would be more likely to stay put than plasma at 150,000,000 k. Or at least be a very different problem.
  4. I like this new euphemism for exploded "one engine failed energetically"
  5. Where are upper stages launched into editorial orbits disposed of? The plane change delta v for a launch from kourou for example is going to be too large to allow disposal in the usual south Pacific graveyard. Do the stages aim for the equatorial Pacific and hope not too hit anything?
  6. TIL that the British navy no longer issues a rum reason, but sailors are allowed to purchase up to 1.5 pints of beer a day
  7. I'm seeing an issue where if I use teh x button to remove a maneuvre node alarm from the list it removesa random slection of alarms from the list
  8. I have discovered the acceleration rate the bug occurs at depends on the whether you have Even Better Time Warp enabld. With it enabled it kicks in at 10,000X, without it it kicks in at 100,000x Ok, a proper bug Report Relevant other mods - Even Better Time Warp To reproduce Create a ship consisting of a 3-px gumbal capsule, with two kerbals inside, recycler enabled and set to maximum For power I used the Sm size uranium reactor and I provided additional food Launch Go to just below the critical warp value (1,000x or 10,000 depending on event better time warp). Observe that, as expected, o2 and h20 do not drop. Increase warp 1 notch - o2 and h20 start dropping rapidly
  9. Great to see sophisticated mods starting to appear. Is it a know issue that above 1000X timewarp the receycler matchs starts failing an dresoureces that should be infinite start dropping?
  10. To be fair the natural intelligence does require a support system that requires more than just the 20 watts. For the average USAian it comes to just less than 10kW.
  11. A paywalled article on Bloomberg suggests that spacex employees are going to be offered a deal to sell their shares at a total company valuation of 175 billion, so going bankrupt imminently seems unlikely.
  12. The Vis-viva equation https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://en.m.wikipedia.org/wiki/Vis-viva_equation&ved=2ahUKEwjNga-h4NeCAxV0VUEAHWH3B_oQmhN6BAgXEAI&usg=AOvVaw3liegRUJSyyy2Os4MBYXOf will get you almost everything you might want. E.g. to calculate the DV to go from a 100km orbit to a 200 km orbit you would use the equation to calculate your velocity for the 100km orbit, again to calculate the velocity for the 100x200 when the craft is at 100 orbit. The difference is the DV for the first burn. Repeat for the 200km orbit for the second burn.
  13. What you are taking about is called a bi-eliptic transfer. https://en.m.wikipedia.org/wiki/Bi-elliptic_transfer As the article explains how f the ratio between the radius of the starting or it is less than 11 it is always better to do a hohmann transfer. If it is greater than 16 it is better to do a bi-eliptic transfer. That is for coplanar orbits, if you are changing inclination then an intermediate orbit with a high AP can give good savings (the opposite of lowering PE to take advantage of Oberth)
  14. Depends on what you mean by "fungi". This is alien biology so they presumably aren't related to our fungi. If by fungi you mean a sessile organism that obtains it's nutrition by breaking down dead organisms like most notable earth fungi then what is producing the matter to break down, and why do they need to grow metres into the air when dead stuff is on the ground? If you want umbrella shaped photosynthetic organisms then sure, except given they aren't related to anything on earth I think the common name given to them is going to be plants because in common use a plant is a "multicellular organism that photosythesises"
  15. 28k /kg can't be the whole cost of gold mining, there will be exploration costs and licensing costs on top of that to get towards the current price of 60k. It's that price that the moon has to beat. If gold on the moon came in the form of conveniently stacked gold bars then I guess transport costs would only have to be 2,000 times cheaper than at present for it to make sense.
  16. For a given energy source and exhaust velocity the relativistic mass of propellant used is simply given by kE=1/2mv^2 no matter what the propellant is. Thrust is proportional to momentum =mv. So if you are within multiple 9s of c the photons or other particles will have almost exactly the same thrust per Watt of power that goes into the propellant. And with photons directly you can throw away the accelerator, the electric generator, the cooling etc and all the inefficiencies that come with them. Yes the thrust of a photon drive is awful, but it is always better than a relativistic accelerator.
  17. If you want an exhaust velocity of you engine is approaching c then you might as well get rid of the particle accelerator and just emit the photons from your energy source. You'll get the same thrust and isp.
  18. The uranium won't suddenly come into a sphere at the centre, it will slowly diffuse inwards. The heat from fission reactions will expand the core slowing the reaction so the uranium will be burned up at a steady rate, just like the hydrogen fusion is stable. Also the subs fusion output is 10^26 watts, the fusion of all that uranium is about the same number of joules so the fission of all the uranium in the sun is about a seconds worth of fusion.
  19. When you can prove to me that you are conscious, or even define it then we can have a meaningful conversation about machine consciousness.
  20. Also there is an InputProcessor mod (that doesn't appear to have a forum thread) that seems to be working for my non-steam game
  21. But 10%? When the starship still needs RCS that could do the job and you need to add the extra mass of shielding the second stage. And as for the idea that the craft is slowing down and needs to speed back up again, that energy is always going to be lost to gravity. There will be a loss to the oberth effect from burning the fuel higher but I can't believe that a few seconds difference makes more than a fraction of a percent.
  22. How would hot staging give a 10% payload improvement? I can't think of any way that the difference isn't trivial.
  23. The fuel tanks probably won't be spherical because spheres are much more of a pain to manufacture than cylinders.
  24. Yup, he's completely ignoring the cost of recalibrating everyone's calendars.
  25. The alien ship isn't powered by something as primitive as hydrolox. That would have evaporated long ago and wouldn't have got it here/there in the first place. It's powered by unobtanium that our physics barely imagines/ can't comprehend at all. Is unobtanium storable? Yes, it says so right there in the script.
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