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PakledHostage

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Everything posted by PakledHostage

  1. I don't think that's fair. The New York Times says that the ship lost power and radioed (presumably to VTS or the Coast Guard) with sufficient lead time to get the bridge closed to traffic. That's why there are *only* 6 people missing. Question might equally be asked why the ship wasn't accompanied by a tug? What were the regulatory requirements for that? And did they have a pilot on board? I suspect that they did.
  2. You can do that from orbit, too. If you use a circular orbit, it's relatively easy to figure out how many seconds after sunset or sunrise you need to wait before doing your ejection burn, so that your escape trajectory out of Kerbin's SOI is parallel with Kerbin's orbital velocity vector. I once used that technique to set up a flyby of Duna with a return to Kerbin on a single orbit. Edit: I also used it to achieve a gravity assist off the Mun, to reach Duna with minimal delta-V. I reached Duna from LKO using about 80 m/s less than the minimum predicted by the delta-v charts. I had to carefully time my burn to flyby the Mun and have it bend my trajectory just right to reach Duna. I recall that was complicated to set up, although they had at least added maneuver nodes to the game by then so I had that tool available to help make it work.
  3. Yeah, the 2017 eclipse was my second (the first was the preceding eclipse in that same saros series). I observed it from northwest of Ontario, Oregon. It was severe clear, and I was focused on my camera when it started (and my daughter when it ended), so I didn't notice it coming or going. The first time, on the other hand, there were big towering cumulus out to the horizon, presenting a big white canvas upon which to paint the shadow. The advance and retreat was very obvious.
  4. I have seen totality in two eclipses. The first, there was a lot of cumulus around, the second was CAVU. The clouds gave a really cool effect to the first one that wasn't present on the second. As the moon's shadow swept over the towering cumulus that were dozens of miles off in the distance, you could see the beginning and end of totality coming. The shadow moves at on the order of 3000 km/hr (more towards the beginning and end of the path of totality), and you get a real primal sense of dread seeing a shadow that big and fast sweep over you. It added another level of awesome to an already awesome experience.
  5. I considered Texas and Mexico, but for better or worse, I'm heading to the northeast corner of the continent (e.g. Maine, Quebec, New Brunswick). Wishing everyone clear skies.
  6. I once drove from Whichita to LA. We only crossed the Texas panhandle, but it was a long drive in total. But road trips are almost always good adventures. Enjoy. Fredericksburg was my first choice of destinations to see it. The western periphery of the path of totality just west of there has the highest probability of clear skies. Supposedly cloud from the Gulf of Mexico often obscures skies as far west as the centreline of the path of totality, but it gets drier west of the centreline. So, even though you're shortening the length of totality by being west of centre, you've got a better chance of seeing it.
  7. Optimistic? After all, there's the lament of travelers through Texas "The Sun has riz, the Sun has set, and here we is in Texas yet"
  8. I see that one group is going to launch a balloon and live stream the video from aboard it: https://www.youtube.com/live/8Ebop4PzFgM? (Note: I got a message saying that the video settings prevent it from being embedded when I pasted it.)
  9. It's 4 O'clock somewhere? Or what is this? Some jargon I don't understand?
  10. Me neither. They're two different things (Oberth effect and vis-viva). @kerbiloid makes a good point with reference to the vis-viva equation, but it neglects the reality that we don't have infinite thrust to instantaneously make orbital adjustments and that there's an atmosphere. Somewhere there's an optimal solution. I am very skeptical that going straight up is it.
  11. Sorry if I have ruffled feathers. Maybe I will just "get my own coat", so to speak. Bye.
  12. Sure, but how are you going to use them in some useful way? That's like saying your orbit changes continuously given the thrust vector. We know that to be true. But how is it relevant to answering what's more efficient: launching straight up, or using a gravity turn to reach an altitude from which we can either burn directly into an escape trajectory, or where we can park temporarily before doing so?
  13. The vis-viva formula only applies when the only force acting on the object is gravity. It's irrelevant when the vehicle is under acceleration due to rocket thrust or atmosphericdrag, such as is being discussed here.
  14. High TWR has the effect of mitigating gravity drag, but intuitively I still think doing the escape burn from a 70 km periapsis is going to be more efficient than going straight up (even with high TWR) for the reason I gave before about Oberth effect.
  15. Because Kerbin's atmosphere is so thick, and it ends at ~70 km altitude, it stands to reason that maximum efficiency will be achieved by doing the escape burn from a 70 km apoapsis. Probably after following a launch profile similar to those in this challenge (minimum delta-V to LKO)
  16. That's the Oberth effect. In both cases, you're ending up in a hyperbolic escape trajectory, but one has it's pariapsis near Kerbin's center (i.e. below the planet's surface) while the other has its periapsis near the orbital altitude that you're ejecting from. In the burn straight up case, you're doing your burn well past the periapsis point, where the vehicle's speed is much lower than at periapsis. The other case has you doing your escape burn from very near the resulting hyperbolic orbit's periapsis point, where you're moving much faster, and therefore achieve a more efficient burn.
  17. Helion has managed to secure itself a lot of positive press coverage, but this "not so fast!" video by ImprobableMatter is relevant:
  18. Boeing doesn't make the windows. Companies like PPG make them.
  19. This is getting ridiculous. It isn't uncommon for them to crack. This shouldn't be news. It's usually just the outer pane that cracks, often due to a problem with the anti-ice heating system. The structural pane is in the middle, protected by polymer and glass layers. And even if the structural pane breaks (e.g. due to a bird strike), the polymer layers can sustain the pressurization loads. Nobody freaks out when someone's minivan window cracks... they stop and get it fixed. That's all that would have happened here, just like the other dozens of times it happens around the world in any given year.
  20. Seems Tom Stafford died today. Another pioneer gone.
  21. Right, but adding significant empty mass to the booster will impact that "if". The original idea didn't involve hot staging, but when that didn't work on IFT-1, they added the exhaust deflector. I recall seeing in the CSI Starbase video below that the deflector has as much mass as an empty Falcon 9 booster. Adding that much has gotta smart...
  22. Do we know anything about the performance that they're actually achieving? They've succeeded in getting a mostly empty, 50 metre long shell into a sub-orbital trajectory, but so did the Space Shuttle. Of course the Space Shuttle's main tank was never meant to reach orbit and Starship is supposed to eventually be able to fill a lot of that empty space with heavy cargo, but how much? Are they achieving their goals? For example, it sounds like the exhaust deflector that was added to the booster to allow hot staging was massively heavy. How much did that impact payload performance? We all know from playing KSP that "the tyranny of the rocket equation" is real... and that's just one example of the payload performance hits that they've had to suffer to make the thing work. What sorts of payloads are they actually going to be able to achieve, after all the dust settles?
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