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Empiro

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Everything posted by Empiro

  1. It's showing atmospheric versus vacuum TWR. In-flight, KER will always show the TWR in your current situation, while in the VAB, you need to toggle it by pressing the Atmospheric button.
  2. It's possible, but I've found that the orbit lines and rendevous can be a bit finicky. I suspect it's due to floating point inaccuracies, but you'll find it hard to tweak your encounter my small amounts. The orbit lines will always jump around. Nonetheless, you don't need a very close encounter in solar orbit. Anything within a few thousand km will do. As you approach, use target mode on the navball and try to push your velocity retrograde into the target retrograde marker.
  3. I haven't used the Trajectories mod, but I think it works pretty well. There is still a bit of risk that you land on a slope, which is also bad if you have a top-heavy rocket, but I don't think Laythe has too many of those. Using jet engines would work well on Laythe, but if you go that route, I'd recommend going for a space plane instead. Since you're bringing somethine separate just for Laythe, space planes are just way more fun, and will help you find a good landing spot. Anything that works well for Kerbin will work well on Laythe (and give you some extra room for error). Just make sure that you're able to land with a full tank! The Jool 5 is both harder and easier than it looks. It's very easy to overplan and overestimate the delta-V requirements. It leads to a complicated launch and assembly since your craft is so large, but once you're at Jool, you'll find everything really easy since you have so much leeway. The other way is to go with a smaller craft, but use complicated and efficient planning. It's quite cheap to transfer between Jool's moons if you're patient and wait for the right times. There exist delta-V maps for Jool moon transfers (https://i.imgur.com/skAIz90.png). Though that's a bit outdated for Laythe, the other numbers are still basically correct. Note how cheap it is to go from a moon's escape to the transfer orbit of another moon. You can also bring mining equipment, but I'm a bit of a purist, and like to do it without ISRU. Some general advice for the planning: Use Laythe or Tylo to reverse-gravity assist to capture and lower your orbit at Jool. Avoid circularizing in low orbit around stuff as much as possible. Instead, leave your main ship in an eccentric orbit with a very high AP and very low PE. This way, if your burn at PE, you'll escape the moon with minimal delta-V. You will need to wait for the moon to be in the right position so that your escape trajectory will be pointing prograde or retrograde along the moon's orbit, however, which is why patience is important. Note that your lander will need more delta-V to land from an eccentric orbit. This may be a problem for somewhere like Tylo. However, even in this case, you could do something like this: have an extra tank of fuel attached to the Tylo lander when you detach from the mothership. Circularize in low orbit around Tylo. Top off your lander while still leaving a bit left in the tank you brought with you. Then, detach from the tank and land on Tylo, do your science, and take off. Rendevous with the fuel tank in low orbit, which has just enough to allow your lander to reach the mothership's eccentric orbit. Essentially your goal is to move as little mass as possible at all times leaving fuel in places you will backtrack to. It's kind of like folks who go on long hikes and drop full water bottles as they are going one way, and pick them back up to drink on their way back. When coming back, it's best to drop your PE down around Jool if you're currently around the tiny outer moons. Note that you will be entering Kerbin FAST. I'm not sure aerobraking is an option even if you have the inflatable heat shield (never tried it lately).
  4. The main considerations for the mission are Tylo and Laythe. The other moons are all quite easy to land on and take off from. The typical design would be (at least) a 2-stage lander for Tylo, and then reusing the upper stage for the other moons, all while refueling from your main craft. For Laythe, the most challenging aspect is landing properly. Laythe has so much ocean that you'll almost certainly be touching down in the water unless you use a space plane design. If you're using the same lander as for Tylo, you'll need to pack parachutes for Laythe, but want those to be detachable, as you don't want to waste mass carrying anything extra for Tylo.
  5. If your closest approach is 11 million km, then you're not anywhere close to Kerbin. The distance of Kerbin to the sun is 13 million km. Without expending an enormous amount of delta-V, the only way to get an encounter will be to wait. You might be able to get an encounter a little bit earlier by putting a maneuver node at the intersection of your orbit and Kerbin's. You won't make the encounter the first time you get there, but if you put a maneuver node there, you may be able to get an encounter the next orbit or the orbit after that with a modest amount of delta-V in the prograde or retrograde direction.
  6. In KSP, you can get all sorts of weird situations like SOIs overlapping and having two planets be on top of one another. As others have pointed out, KSP planets are "on rails" so there's nothing that can disturb their orbits. Realistically, if Eeloo encountered Jool, it'd likely be flung out of the system, or have its orbit drastically changed. In KSP1, there's the mod Principia that simulates n-body physics. It turns out that many of planet-moon systems aren't quite stable when you do that (for example, Minmus would be flung out of Kerbin, and many of Jool's moons would be unstable).
  7. Believe it or not -- I wouldn't mind if after a few years of KSP2, KSP3 came out with even more parts, features, and improvements. More realistically, I don't mind part DLCs, but any new systems that gets added (e.g. ground science, inventory, mission builders, etc.) needs to be integrated with the base game for everyone. When I look at KSP1, I just feel it's really a shame that a cool system like the mission builder just kind of gets left by the wayside because it's not integrated with the main game modes. I completely agree that KSP 1 has its share of cobbled together systems. KSP2 is the chance to fix that, and ideally, avoid gameplay fragmentation via lots of small DLCs poorly integrated into the main game.
  8. I don't mind spending money for more content, but I'm against DLC in a game like KSP. I want the gameplay experience to be all nicely integrated, and I feel like the DLCs for KSP1, while alright, have made the experience feel disjointed. Take Making History -- some nice new parts, but the real meat of the DLC, the mission system, is kind of just there. It doesn't integrate at all with the contract system or anything like that, even though it'd be super fun to have complicated contracts like what the mission builder can do. As a result, it just gets ignored and forgotten in most games. Breaking Ground was somewhat better -- the inventory system got added to the base game, so at least mods can make use of it. Still the deployable science and robotics and rotors just feel like they don't really fit in with the rest of the game.
  9. Yes, you have the right idea. The thread for JNSQ has a delta-V map, so you should use that. I believe it takes 5000 m/s to reach Kerbin's orbit. The only caveat is that if any stage's TWR ever becomes too low (especially before you get into LKO), then your rocket may use up more delta-V or even fail to reach orbit.
  10. How many m/s is your maneuver? If it's significantly more than 2000m/s, consider tweaking your maneuver or waiting for a better window. If you still have a 40-minute burn, try a higher orbit to start with. For Kerbin to Jool, the gate orbit is at 250km. This altitude minimizes the delta-V to get to Jool (not counting the delta-V required to get into that orbit). This will reduce the burn you have to do and give you more time to do it. You can also split the maneuver into pieces. Do half of the burn so that your AP is high but within Kerbin SOI still, and then complete the burn the next time you come around. You still need about 950-1000 above Kerbin escape so you're still looking at a 20 minute burn. One other thing you can try to do is to ignore the maneuver node once you're significantly past it. Once you're about 5 minutes past the maneuver point, just burn prograde. It will cause your ejection angle to be a bit off. One way to help plan around this is to split your maneuver in KSP -- place one maneuver that you can do within ~5 minutes at Kerbin's PE. Place another one about 5 minutes after that one that you can do in 5 minutes, and so on. It's a pain to do any corrections in timing (you'd need to move all your maneuver nodes around), but it will tell you with good accuracy where you'll end up.
  11. The delta-V maps are just estimates and often are on the conservative side, just in case your TWR is very low or if you are slightly off and need to make corrections.
  12. That should be more than enough. You should see what happens if you turn off SAS. Like others have pointed out, mach 2 at 2000m is quite fast. It may simply be very hard to keep a long rocket stable at those speeds.
  13. This often happens with long rockets that have SAS enabled. Because of the aerodynamic stresses, your rocket is bending slightly. SAS tries to counter this, but your control point is at the top while your thrust vectoring and winglets are at the back of your rocket. This very easily causes an over-correction, which results in your rocket oscillating back and forth. Adding struts will decrease the amount of flex your rocket has Disabling SAS can prevent the oscillation from happening, but if your rocket is bending too much, then it may tumble out of control or break apart Reducing speed while low in the atmosphere will reduce the overall aerodynamic stress on your craft
  14. More of a set of mods, but it's RSS/RO/RP1 for me. I've been playing KSP for a long while, and I really want to take things to the next level of realism. However I've been kept away because of the complicated set up, the fact that the mish mash of mods don't really support the latest KSP, the bugs and conflicts, and the general jankiness (how they handle the axial tilt for example -- yes I know it's a KSP limitation, but still).
  15. I like Kerbal Construction Time a lot, but I definitely think it should be kept as a mod rather than something standard. You want players to be able to experiment and tweak things quickly. For new players, they're going to have a lot of failed rockets and launches.
  16. You can launch just as it flies overhead. You'll be behind your target and you should go into an orbit just over 70km. You'll be catching up and shoud be able to get an encounter fairly quickly.
  17. Having some sort of career mode / guided challenge mode is important, but I agree that KSP1's career mode is severely lacking in many respects. I can also appreciate how it's tough to get right though. You want players to do interesting and new things while providing them with a challenge of some sort (not costing too much, not taking too much time, etc.). At the same time, you don't want to put players in a no-win state if they fail some of those challenges. KSP1 sort of gets close with mods like KCT and Kerbalism, but even then, a lot of the gameplay is focused on grinding enough funds to upgrade your buildings rather than trying to come up with interesting rocket designs and challenging yourself with new types of missions.
  18. Unity is a great engine, but there have been a number of talks where the developers have talked about all the hacks they needed to put in to make KSP work. I totally agree that it's not feasible for them to develop a custom engine for KSP2, though one can dream. I like the idea of RSS a ton, and I want to try it, but I've personally been kept away by the general wonkiness of getting all the mods to work together. I really hope that KSP2 is able to work around a lot of the limitations KSP1.
  19. It sounds like the question is, should you use lots of small boosters and lots of stages, or one larger booster? Generally, the answer is "somewhere in the middle". Getting to orbit by the end of the 2nd stage is a pretty good goal. I typically use stage-and-a-half (liquid engine + detachable SRBs) designs to almost get into orbit. That way, the dropped stages crashes back into Kerbin. The answer to your other question is yes, you should generally drop anything that is empty. Decouplers add mass, but they're very light compared to even the Flea. In career mode, I'll occasionally hold on to something like a Hammer for a little while, because an empty Hammer is fairly light and decouplers are pretty expensive.
  20. I've only done one such mission, and tried both the sky-claw and rover design. The sky-claw is really challenging because you're essentially attempting a docking maneuver with very limited time before running out of fuel, and you'll need to be constantly adjusting the thrust to maintain altitude. At the end, I went with a rover that was essentially a rocket with a claw in the front. To land, it had wheels and radial engines that lands it horizontally. I also had a horizontal probe core on the side to help with the horizontal landing. For most of the way, it uses the efficient engine in the back, and when it's just about to land (maybe 100m off the ground), I deactivate it, switch to the radial engines, and control from the horizontal probe. After landing, I drove over to the target and clawed it. To get back into space, I turned off some of the radial engines (because the CoM shifts after you grab your target), and just used the engines to pitch the nose up so that I could use the rear main engine to boost into space. All in all, it was fun and challenging, but so time consuming that I haven't done such a mission since.
  21. Yes and no -- it comes down to whether both engines have enough delta-V to get you where you want to go. I don't know what your entire rocket looks like and I don't know where you're planning to go with it, so I can't tell if both engines will work or not. However, you're right that 310 vs 350 isn't *that* huge of a difference, so in many cases, both would work. If the ISP difference were 221 vs 350, then it's highly likely that either: the 221 engine wouldn't have enough delta-V, OR the 350 engine has so much excess delta-V that I can remove fuel and get the same TWR. A slightly more advanced tip is that efficiency becomes more and more important the later your stage is. The design of a stage not only affects that stage, but also the performance of every stage before it. It's critical that your upper stages are efficient and light, while low ISP solid rocket engines are totally OK for the 1st stage. For a 2nd stage, it matters some, but in my experience you have some flexibility in your selection.
  22. You generally don't need to calculate exact ISP and TWR values at specific altitudes -- for example at anything 20km and above, I simply use the vacuum values (even if you start burning at 15km, you'll gain altitude very quickly). The ISP and other guidelines are there to help you whittle down the engines you should be looking at different stages, but the actual TWR of your rocket and delta-V determine the construction. If both the Poodle and Bobcat have enough delta-V, then I would go with the Bobcat -- the better TWR means less burn time, and a more forgiving flight trajectory (I don't need to worry about falling back down). If I have to go with the Poodle to get enough delta-V, then the low TWR also helps inform me of my choices for the 1st stage -- I know I would need a rocket with better TWR and fly a slightly more vertical trajectory. For your first stage, your choices of engines are all pretty good, and I think each design could be viable. My final choice will depend on my 2nd stage choice (if Poodle, then higher TWR). Real-life rockets like the Saturn V had an on-pad TWR of only 1.15 or so. In KSP, a 1.15 TWR rocket requires roughly 3800 m/s to make it into orbit, compared to a 1.6 TWR rocket that only requires 3500 m/s.
  23. This is just a general guideline on how engines in KSP compare, so you'll want to do some exploration and studying on your own (the KSP wiki is helpful). The two most important stats of an engine are the TWR and ISP. The other stat to look at is mass, but it's much less useful. ISP is important because as we've discussed above, it's the basic efficiency of an engine, taking both thrust and fuel consumption into account. Vacuum ISP is typically used since you spend most of your time in a vacuum (as soon as you're 20+km high, the ISP is very close to vacuum). If you compare all the engines, you'll notice that engines with really high ISP in vacuum tend to have very poor ISP in atmosphere (the lower ISP comes from having lower thrust, while still consuming the same amount of fuel). KSP doesn't provide the TWR, but you calculate it by dividing the thrust by just the mass of the engine and nothing else (so for the Twin Boar, make sure to subtract away the mass of its 36-ton tank). An engine with great TWR on its own will also provide great TWR attached to a rocket. TWR is important when taking off and landing, and you don't want it too low in space (<0.1 in space is quite problematic. I generally have more than 0.5 to avoid long burns. If you compare all the engines, you'll notice that engines with really high TWR in vacuum tend to lose less ISP and thrust in atmosphere, so high-TWR engines have good TWR nearly everywhere. The VAB also has a TWR display that shows you atmospheric and vacuum TWR of your craft in different environments. Note that raw thrust is not something I look at on its own. This is because TWR is a more useful stat that encompasses both thrust and mass/weight. If an engine has a great TWR but not enough thrust on its own, you can easily double or triple-up an engine to get the oomph you need. Finally, mass matters, but ONLY because you can't have half an engine. TWR already takes into account mass. Engines like the Spark get used on small crafts because you can't have a quarter-Terrier with 1/4 of the thrust and 1/4 of the mass and same ISP. All this provides us a basic way to compare engines and summarize the important points: You want engines with both high TWR and high ISP, but those don't exist -- engines with great TWR tend to have relatively lower vacuum ISP and vice versa. Low TWR engines have really low ISP in the atmosphere, which means their TWR becomes abysmal, and are worse in every way compared to high-TWR engines in atmosphere (as it has both lower ISP and TWR). More massive / late-tech engines tend to be better in both TWR and ISP and break away from the trend a bit. For example, the Poodle is heavier than the Terrier, but actually has better ISP and TWR in vacuum. The Aerospike is pretty good in every situation (though never the best). These engines are great if you have the tech and big enough craft. You'll find that for small crafts, these engines provide more thrust than necessary and add too much to the mass. (The engines in KSP are pretty balanced these days, but in the early Beta versions, some engines clearly were outside of these trends) Putting together these stats, you can roughly group engines into three classes: Lifter engines with high-TWR and relatively poor vacuum efficiency. Mainsails, Reliants and SRBs fall into this category. They're engines you use off the launch pad in Kerbin and Eve, where there's high gravity and atmosphere. Vacuum engines with really great ISP but poor TWR. The Terrier is the most accessible example of this. Vacuum engines are great to use as soon as you're high up in the atmosphere. Even though the TWR is poor, they're still useful on landers because most places you land on have no atmosphere and low gravity compared to Kerbin (TWR of only 1 on Kerbin is 6 on the Mun). Duna's atmosphere is thin enough for most vacuum engines. Sustainer engines that are a middle ground. I find the Skipper a really useful example in this category. You can use them off the launchpad if you augment them with SRBs, or use them as a second stage that puts you into orbit. They're also really useful to keep using in Low Kerbin Orbit. Hopefully this is helpful to you. Let me know if you have more questions.
  24. Here you're calculating acceleration by dividing the thrust by mass, so your crafts will accelerate at 19.61 and 19.59 m/s/s. The TWR is a Ratio between the acceleration due to the Thrust, divided by the acceleration due to gravity (the Weight). Your TWR changes depending on your reference body and how far you are from that body, though if omitted, it's typically relative to surface of Earth or Kerbin (both 9.8 m/s/s). To get TWR, you'd divide your answers by 9.8 (or do what I do, and just divide by 10) to get a TWR of around 2. Like many folks have said, TWR matters when lifting off. Under 1.0 and you won't be able to lift off at all. In orbit, TWR matters very little unless it's extremely low (<0.1g). I think you're on the right track. I think your misunderstanding is coming from thinking that more thrust = more efficient, without taking fuel consumption into consideration. The Terrier will take 4x longer to burn, but compared to the Reliant, it will be able to use the same fuel and burn for more than 4x longer. The ISP measures efficiency. The higher the better. If you're interested in the math, it's calculated by taking the Thrust and dividing by fuel consumption per second, and then dividing by 9.8/s/s (it is by convention to measure ISP in seconds). KSP gives fuel consumption in weird units (not kg/s) so it's good that it provides you the ISP information in seconds. However, the ISP isn't the full story, because the mass of the engine matters too. The Terrier is often chosen because it both has good ISP and low mass. It is almost always chosen over the Reliant in space. Poodles have only slightly better ISP but far more mass, so its good for larger crafts. When comparing the Poodle with the Reliant, it's a bit trickier, since the Reliant is lighter, but the ISP is lower. KSP shows you the delta-V in the VAB, but by default shows you stats for in-atmosphere, which is really bad for engines like the Poodle. In the VAB, try out the two different engines, making sure to set the Delta-V mode to vacuum. If you're interested in learning the general rule about engine selection and how to judge an engine, I can help with that. It helps you determine what engines you should and shouldn't be looking at when deciding what to use.
  25. The key is getting your orbit to match as closely as possible to your target before your encounter. If you're coming in directly from a Jool escape trajectory, then naturally your orbit won't look anything like your target's. Instead, try to use gravity assists to capture into a Jool orbit, and then use more assists to adjust your orbit so that it closely matches the moon you want to get to Generally, it's OK if your AP or PE is some ways off, but you want the other side to be just barely touching your target's orbit and have the encounter happen there (so it looks like a Hohmann transfer). Having a big inclination difference is also bad. Finally, get your encounter as close to your target as possible, which will also cut down on the delta-V you need to capture (maximizing Oberth effect). Note that it IS possible to efficiently capture directly into a moon's orbit, but you'll need to follow the advice above (no inclination difference, having the orbit around Jool just touching your target's, and getting the encounter there). However, it might be hard to time the encounter just right.
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