Loren Pechtel

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About Loren Pechtel

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    Senior Rocket Scientist

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  1. I couldn't check, the box that tells you about the crash blocked everything and couldn't be dragged. However, I got the deorbit point dialed in right, put it in the ocean within sight of KSC at about .2 m/s (chutes plus the rocket) so it didn't bobble at all (the usual cause of water breakups I've seen is the rocket going too deep and being destroyed after the rebound), it looked perfect. Then it slowly tipped over and every bit of the rocket that mattered was obliterated, I was left with a pile of engines and fuel tanks. It seems completely insane but I think the only way this design will fly is if I put decouplers on it and blow off the boosters at touchdown.
  2. I decided to try something. I took the wheel off and put the very same wheel back on the outer part (so now there are multiple wheels)--I never picked up a different part. Now it steers properly. The only thing I can think of is roundoff--maybe the wheel's rotation is being rounded to zero. It does turn out I need more power for some reason, though--the battery drained while doing nothing in orbit. I guess those tourists had too many lights on. And now I'm really confused!! It didn't come down exactly where I planned but I thought I was doing ok. I put it in the ocean as intended at about 3.5 m/s. I hit recover and walked away to deal with a problem. I come back to find it blown to bits by a hard landing. How do I have a hard landing after I've already landed?? I've seen rockets damaged by tipping over in the water but I've never seen one annihilated.
  3. I do have a much heavier vehicle with the same wheel but this is not a case of being out of power! That was my first thought, but I looked, the battery is nearly fully charged. I expect it to turn slowly but it's got 7 minutes to turn maybe 10 degrees for the circularization burn. I do not believe I need panels--the battery will be used to orient for circularization, but then recharged by the circularization burn. It will be used again to reorient, partially charged by the deorbit burn and then probably fully charged when I burn to get it down to opening velocity (aerobraking alone won't slow this beast anywhere near enough.) Once the chutes come out there's no more need for SAS anyway.
  4. (Note: I've been away from the game for a while, maybe something has changed that's messing with me.) I have a probe core--the OKTO2, tweakscaled up to fit. I also stuck Jeb on board after the first flight got stuck. I have power (although no way to generate it--this is a tourist hop, it's only staying up a fraction of an orbit.) Note that the engines gymbal if I attempt to turn the rocket. I have a reaction wheel. Furthermore, I have two designs. The first is the core of the rocket--chute, core, wheel, passengers, fuel, engine. This flies fine and has successfully completed a mission other than coming down in the mountains. The second design adds a ring of chute/passengers/fuel/engine, all exactly the same as the core--I'm simply scaling it up to carry more tourists. Mechjeb takes this up but won't circularize. The only thing unusual here is the lack of decouplers--I'm bringing the whole thing back and trying to drop it in ocean (no way it's not going to fall over on land) off KSC.
  5. How is that a balance lever? What I'm suggesting would simply reduce the number of times you have to tend the lab, it wouldn't change the output. It's just a reduction of micromanagement.
  6. Note that I said the extra should be a buffer, it shouldn't participate in the yield calculations. I realize that if it did it would certainly be unbalancing. I don't see any balance issues in having an infinite holding capacity for output. That's simply a matter of not having to tend it as often.
  7. Yup. Some time ago I tried the science lab route to massive science. I had already grabbed all the science from the Kerbin system so I went to Duna (or was it one of the moons? I forget.) I had a rover with all the science instruments and Bon Voyage to guide it. A separate mission landed a science lab. Gather all the science, upload to the lab, launch another copy of the science lab rocket, unmanned. When the lab was done the scientist goes next door to the next lab, repeat the cycle. Then I discovered the mod that allowed you to use the extra science to improve parts was incompatible with Tweakscale. The one thing I did note about the science labs that I didn't like is they have limited capacity. There would be less management involved if their capacity was infinite. Since their yield is tied to how much science they have the extra input should be a buffer that keeps them full rather than simply increasing their working capacity. Note that in career mode once you have progressed far enough you can fund your whole program this way and not take another mission if you don't want to.
  8. Yeah, I had no idea there were hab time multipliers there, either. The only way I knew to get high hab time was something like that earlier rocket studded with observation portals, or else a bunch of the big rings.
  9. I do have a problem with how hab time works--we need some bigger parts. Look at your example of a 5-year ship. There are a lot of parts on there to get that 5 years. I'd like to see some bigger things that provide the same benefits for similar cost & weight but using a lot fewer pieces. If crew capacity and bonuses were altered by TweakScale that would probably do the job, although I would like to see an in-line module with bonuses.
  10. This is Kerbal Space Program, not M.U.L.E.
  11. It's not actually your center of gravity that matters, but rather the angle between the ground and the center of gravity. The smaller the angle the more stable the rover. Putting your mass low helps but it also helps to make your rover big. It will be a pain to haul to orbit but it's a lot less likely to crash. Also, if you're willing to spare the mass & power, use reaction wheels. Bring along a pilot or probe core capable of running SAS. With SAS on it will use the reaction wheels to try to keep the rover from flipping. I've taken rovers with big reaction wheels over terrain where you end up sliding down a hill--when sliding you can't hope to be careful and thus any ordinary rover will most likely crash.
  12. I'm not contradicting myself. On launch a rocket goes straight up, then soon tips with the rotation of the body and accelerates to orbit. This is the lowest energy trajectory, you want to do the exact reverse to land with the least fuel. The first burn puts your periapsis a bit above the point where you want to have killed your horizontal velocity (the reverse of your circularization burn.) You then come in, lighting your rocket at the point it will kill your horizontal velocity over your target. This of course means you end up lower than the orbit you were in, hence the reason your periapsis is higher than your objective. As you approach your target you tip more vertical as you can't just suddenly turn vertical when you complete your burn. (Now, if you have a small rocket with the vastly-overpowered rotation capability of many such rockets in KSP you would be better off not rotating until you're over your target.) You still have substantial vertical velocity at this point, optimum is you shed it in a suicide burn. This isn't what Apollo did because they took the safe route. Their approach burned considerably more fuel, though.
  13. I don't think keeping the downward momentum under control is what you want. You want to leave the burn for as late as possible. The ideal landing is a gravity turn in reverse. Without knowing exactly how the rocket will perform you can't do that precisely, though, so you're going to need to allow some margin.
  14. A "transfer window" normally refers to a situation where you have three bodies involved. The math is imprecise and much more complex than what you are thinking of with a Hohmann transfer. For a Hohmann transfer you simply need to find when you're at a point directly opposite where your target will be in half an orbit. (If that gives a negative solution you missed it, look for the next such point.) Things like Transfer Window Planner and the similar functionality in MechJeb, however, are looking at a more complex problem. 1) Your target is in another SOI. The simple math of a Hohmann calculation won't give the burn you need. 2) As there are three bodies involved (the ship, the starting planet, the arrival planet) there almost certainly isn't a perfect solution. At the point your planets are lined up perfectly it's almost certain your ship is not. Thus, rather than a simple equation that spits out one answer you have a much more complex equation that must be tested over a whole range of values in order to find acceptable missions. For a Hohmann burn the fuel use for a non-optimal burn goes up very rapidly as you get away from the optimum, you're going to want to do such burns as close to perfect as you can. For an interplanetary burn the penalty goes up much slower, in general waiting around for your spacecraft to reach the correct point in it's orbit for the burn is going to have a very minor penalty. (However, if you're orbiting near the edge of Eeloo's SOI and try to burn for Moho the error is so big you might as well forget about it--exit Eeloo's SOI on the inward side and then do it as a Hohmann maneuver.) You can even send a fleet doing it one spacecraft per orbit without a big penalty. (Just make sure their arrival times are also staggered as you can only fly one craft at once!)
  15. Stages are only recovered when they go below the IIRC 22km line. A stage that doesn't go that low will simply remain in "space" (even if it is actually orbiting entirely in the atmosphere!) and not be recovered.