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sevenperforce

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  1. sevenperforce
    Not with Tweakscale. And even without, what do you optimize for? Biggest or lowest count?
  2. sevenperforce
    Nice! If you're doing it with RSS/RO, it may prove a little too difficult, so you can relax some of the engine thrust requirements.
  3. sevenperforce
    Not sure what geometry you're imagining, but neither gravity nor acceleration require time or distance to "accelerate" the fuel. The downward force on the fuel column will be several gees from launch to burnout. Yes, the chamber will need to be longer and thinner. With a gel, however, you aren't dealing solely with a burn surface; there will be significant droplet entrainment and mixing. The only reason I'm still proposing this design is that IF it turns out to work in preliminary tests, and works well, it offers significant advantages. Of course it might not.
  4. sevenperforce
    @Bottle Rocketeer 500 @CaptainTrebor @DunaManiac @53miner53 @Physics Student @Nefrums @foobar @HiThere!2 @Spaceman17 As proof that this challenge is readily doable, here's Falcon 1 and Falcon 1e: Falcon 1: Falcon 1e: I've also done Falcon 5 and Falcon 5R, but I want to see other designs before I post them.
  5. sevenperforce
    Livestream is live and streaming: https://livestream.com/accounts/25660170/events/7633093
  6. sevenperforce
    Yeah, I'm not sure whether it should be shear-thickening or shear-thinning. We would likely use a paraffin or similar liner to form the initial combustion chamber shape, so flow on the pad isn't a problem. If it's something like oobleck, then the pressure from the combustion chamber should keep it fairly firm while it flows from above, though I'm not entirely sure that would work. We could simply have the initial combustion "wall" be painted/sprayed with a suitable catalyst. The reason I like a catalyst bed is that it would probably allow lower throttling.
  7. sevenperforce
    Yeah, I've considered using a drop-away parallel booster design like that for some of my sugar rocket stacks. The trouble is that no amateur motors will have simultaneous ignition, identical thrust curves, and simultaneous burnout. The linked peroxide rocket had a very low TWR, so low that they added a single small SRB to give it added thrust climbing up the launch guide so it could be aerodynamically stabilized. The SRB was supposed to separate at the top of the launch guide, but instead it did not and produced off-axis thrust, which torpedoed the whole thing. Wouldn't be an issue for us, because a hybrid has all the thrust we could possibly want. The plan would be that gravity and acceleration are the primary forces promoting fuel feed; ullage pressure at the top is only high enough to prevent chamber pressures from pushing up on the propellant. A lightweight annular plastic disc may be used at the top of the fuel column to prevent tunneling. The "chamber" would most likely need to be longer and narrower than shown above, as with most smaller rocket engines. It'll be more solid than gel. We may be able to utilize non-Newtonian properties. Pressure in the tank is going to be higher than in the chamber, so flow will always be in the direction of the chamber. Thus, the flow of undecomposed HTP should be enough to cool the catpack.
  8. sevenperforce
    This is awesome!
  9. sevenperforce
    Can you please give evidence of that? EM-1 was originally planned as a free-return when there was a chance they'd be flying it with crew, but since they are flying it unmanned, they'll be tightening the free-return and doing a retrograde orbit instead.
  10. sevenperforce
    Hate to nitpick, but I hope this will be constructive (no pun intended)... What counts as a space station? A hab and solar panels? Does it need multiple modules? A propulsion bus? A lifeboat? A cupola? I think there have already been "largest space station in a single launch" and "largest space station with an SSTO" challenges, so you'd probably want to come up with something new. You could do something focused on orbital assembly, where a series of modules are packed tightly together and launched and then an assembly bus is used to connect them all together. Try to make a challenge with a well-defined goal that entrants can optimize toward.
  11. sevenperforce
    Sabre engines (well, the RAPIERS) are absolutely allowed. That's what is required for the spaceplane SSTO version. The bypass hydrogen will be burned in bypass ramjets, not in the main combustion chamber (it requires more hydrogen to precool than it can use). But the reason for LF limitation is that real-life hydrogen is VERY lightweight and not dense at all. Tankage ratio on stock tanks is way too good for hydrogen (though worse than most bipropellant rockets).
  12. sevenperforce
    Not anywhere near my house, you aren't.
  13. sevenperforce
    Yeah, docking a booster to the ISS is impossibly stupid. And they were all "plus if this gets refueled in orbit it can go further!" Uh, what? You can't refuel a pressure-fed engine, there's no restart capability, there is no inherent advantage to refueling an SSTO in comparison to a typical upper stage, AND who on earth would send a refueling mission to refuel an empty, heavy booster?
  14. sevenperforce
    Delta Heavy is not a very good comparison, given that we're talking about 3 engines vs 27 engines. Will there be a 27-engine static fire?
  15. sevenperforce
    I tested Falcon 1, Falcon 1e, and Falcon 5 with boilerplate payloads and it was a cinch. I highly recommend using a gimbal-limited Vector as your primary engine, tweakscaled down slighly if you have Tweakscale. At 40% thrust-limit, it has NO trouble getting Falcon 1 into orbit with plenty of fuel to spare. I'm using a tweakscaled Swivel as my replacement for the Kestrel on the upper stage, but YMMV.
  16. sevenperforce
    @CaptainTrebor @DunaManiac @53miner53 @Bottle Rocketeer 500 I added Falcon 5, Falcon 5R, Falcon Air, and Tesla Model S!
  17. sevenperforce
    Oh, I did. There is a whole set of discussion above about what constitutes a good challenge. And by the time you were asked, I had already built the SSTO and put it in LKO.
  18. sevenperforce
    This rounds out the construction of the Deep Space Gateway. I have some suggestions for how to handle the further missions, if you want them.
  19. sevenperforce
    Finally, here's Exploration Mission 5! Very little direction on what constituted an "airlock" so I just did a service bay and a cupola with ports on each side. The module has no fuel or thrusters of its own. Liftoff! Used a much more shallow ascent on this mission, just to see how it would work. Burnout from underneath. Super cool shot of the SRB sep! Was somewhat worried that the super-shallow ascent might be more than the LES tower could handle. Didn't turn out to be a problem, though tbh an abort at this stage would probably not work out too well. As usual, I need to keep from getting into orbit on the core. Warped around to apoapse for separation. Gimbaling around gently. Fairing away, circularizing! Circularized. Flipping to grab the airlock module. Coupled, extending panels. Set up the TMI with EUS disposal. TMI complete, with lotsa fuel to spare. EUS jettison. Burning for capture! Wonky injection because of this awful polar orbit, so I'm setting up the best intercept I can get. Burning for the intercept. Close enough to match orbits. Matching orbits at full throttle. Steady as she goes... Loving this shot of the Deep Space Gateway with Orion approaching, Kerbin in the background and the dark side of the Mun at left. Final approach. Swinging around on RCS to dock. Docked! Decoupled Orion, swinging around to dock on the side of the hab. Approach... Docked! Awaiting further instructions.
  20. sevenperforce
    READING COMPREHENSION FAILED! 1. It says "challenge as originally defined"; you originally said SSTO and only later added the completely different requirements of HTOL. 2. I did return the SSTO to Kerbin. The base is on Laythe. What else do you think I did?
  21. sevenperforce
    Done!
  22. sevenperforce
    Done!
  23. sevenperforce
    This satisfies the challenge as originally defined, though obviously not with all the many add-ons since:
  24. sevenperforce
    Yeah, this is super easy.
  25. sevenperforce
    Yes, it is! I've tried it quite a few times now.
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