herbal space program

Not sure what you mean by "minimalist", nor exactly what aspect of the Mars Direct concept you mean to emulate, but this is the smallest Duna return capable vehicle I was able to come up with a while back: It has a mass of only 5.7t at launch, and uses a Rapier ascent stage and Ion propulsion to get as much dV as possible. If anybody has a smaller one, I'd like to see it! But maybe that's not what you meant...

If you do it to the right degree, it actually produces less drag at high speeds, because it lets you keep your fuselage pointed directly prograde while your wings still have some angle of attack. Adding more rather than less wing area can also somewhat counterintuitively reduce drag at high speeds/altitudes, because it lets you keep your fuselage pointed more prograde up where the air is really thin.

This is a very nicely written tutorial, just keep in mind that it is so old that it says stuff about the KSP aero model that is no longer true.

Some more advice on building a plane that will actually fly: 1) get to know the center-of-mass (CoM), center-of-lift (CoL), and center-of-thrust (CoT) indicators in the SPH. A good plane will have the CoL indicator on or just behind the CoM indicator, both when the tanks are full and when they are empty. Achieving this balance is not trivial, and I highly recommend using wet wings rather than just tanks to help you with that. Trying to mount at least some of your engines further forward along the sides rather than having them all in the back helps as well. If your CoL is too far behind your CoM, your plane will keep trying to nose down. if it is in front of your CoM, your plane will flip over and try to fly backwards the second you go off prograde. 2) Don't forget to put control surfaces! You'll need both horizontal stabilizers and a tail fin of some kind near the back, and sometimes a canard on the front can be quite helpful as well. Also, surfaces that are meant to control your pitch should be either well forward or well aft of your CoM. 3) Put most of the weight on the rear wheels, but don't have your tail sticking out too far. Takeoff and landing are much easier if your rear wheels are relatively widely spaced and just a little ways behind your CoM, while your nose wheel is as far out in front of your CoM as you can put it. This also puts quite a bit more weight on your rear wheels, so they should often be one notch beefier than the nose wheel. The front and rear wheels should also be mounted so that your plane is pitched slightly up on the runway, so that your wings generate lift as soon as you get rolling. As was mentioned before, tilting the wings slightly up in the SPH is often a good idea as well, as it allows you to generate lift while your fuselage is pointed directly prograde, which minimizes drag in flight. Having said all that, make sure your tail section doesn't protrude so far behind the rear wheels that it will hit the runway when you pitch up for takeoff! 4) Familiarize yourself with "absolute" vs. "local" mode when using the "rotate" tool in the SPH. You should make sure all your wheels and control surfaces are absolutely horizontal/vertical with respect to your fuselage before taking off, or else you could see some bad behavior. 5) Consider turning off the steering on some or all of your wheels, at least for takeoff/landing. I generally find that they respond too aggressively to control inputs in these situations, greatly increasing the probability of disaster. Happy flying!

You make a good point. Changing the speed and/or altitude probably would have worked. I'm pretty sure that at 20km and that speed, the aero forces wouldn't have been strong enough to snap off my wings, although that would have represented re-flying a lot of the approach. Another thing that probably would have worked is changing my motion where I was so that it had an upward component that would reduce the force on the wings. As to changing the attitude of my craft where it was to unload the wings, in that situation on Eve, the only thing that did that seemed to be going into a vertical nose dive, which becomes really fast really quickly. In the end I determined (based on my first landing attempt) that invoking unbreakable joints in alt-F12 for just the couple of seconds after loading was in fact only temporary, so it seemed like the least amount of cheating to get me around this problem. My second attempt at landing was successful, so I'm past that roadblock now, but I do think my experience with this does point out an area where the game really isn't behaving the way it ought to. I wouldn't call it a bug per se, but obviously the way they have combined the relaxed save state of the craft and the instantaneous activation of the physics engine in the atmosphere can readily produce catastrophic events when they shouldn't happen. As a plane enthusiast, I do hope they get around to fixing that behavior at some point, at least before KSP2 rolls off the line.

Thanks for the explanation, that makes perfect sense to me. And obviously you can't fix that by editing the save file. Perhaps if I enable auto-strut and rigid attachment everywhere that will help going forward, although there's obviously no time to do that on my save while flying. I'll try your suggestion about the gravity parameter. Maybe I was just really lucky, but after I turned "unbreakable joints" off in alt-f12, it really seemed like I could still get away with stuff that would have broken my plane up before, and I want to land it fair and square. As an aside, it really seems like it shouldn't be so hard for them to fix this. They should just apply some kind of damping to the structure's movement for the first second or so after reloading so that the momentum of the parts doesn't apply double stress to everything. I suppose that might open the door to some exploits, but it still seems like a reasonable tradeoff to me in exchange for not having perfectly good airframes spontaneously disassemble upon loading.

Hello all, I'm playing through a career game with the BG DLC, and part of that is the propeller-driven Eve spaceplane pictured below approaching the place I want to land: It handles re-entry just fine, and getting it to stable flight on the props and keeping it that way is a bit tricky but doable, as is landing it based on sandbox testing. So long as I don't push it too hard or lose control with the props (easier said than done!), it holds together perfectly well. What it doesn't seem to be able to survive however is quicksaving/quickloading in atmospheric flight. No matter how slow, straight, and level I have it before I hit F5, it always seems to break up instantly when I reload it, forcing me to start all the way back in early re-entry if I mess up anywhere in this long, long phase of flight between around 40km and the ground. Basically as soon as the physics load, the wings just snap off no matter what I do. So my my question is this: is this some kind of a bug in the vessel file or is it just some inherent bad feature of how the game handles static vs. dynamic loading? In the former case, does anybody know how to edit this behavior away? I'm not above using physics cheats transiently either, since it seems so unfair, but it appears that once I load a vessel with "unbreakable joints" enabled, it stays that way until I reload it even if I turn it off, which of course takes all the challenge out of landing it. Thanks in advance for any insights from the knowledgeable!

the way I figure it with my mediocre math skills is that no matter how you enter Mun's SOI, you're going to have at least enough gravitational potential energy to put you back to that altitude after your PE. Any net motion towards Mun that you have as you enter will add to that potential energy, and by definition you can't enter Mun's SOI with a net motion away from it. So the best case is crossing the boundary with an infinitesimal amount of radial motion towards Mun, in which case only an infinitesimal amount of retrograde boosting at PE is required to keep you from going back out. In my case, I think what happened is that I just grazed Mun's SOI on its inside boundary at the AP of my ship, moreover from a PE that was considerably higher than LKO, which allowed me to enter it with a motion that was small in the sideways dimension and minuscule in the radial one, just enough to avoid unplanned lithobraking. If you manage to enter the Munar SOI with that type of motion, I can see how a rounding error might put you directly into orbit, as @Zhetaan described above. But that was I-don't-know-how-many versions ago, so it doesn't surprise me that they've since cooked up some kind of a kludge to make achieving orbit due to a rounding error impossible. In any event, I'm pretty sure that trying to shoot for that is never going to be the most efficient way to get into orbit, because you can't do it from an Oberth-friendly PE that is much lower than your point of entry.

You sure don't seem like that to me. I don't think I really have the patience to try something like that either, but indeed, that's the direction the wheels in my head were turning!

Hmm, makes me wonder what happens if you place separate control points that are all within physics range of the adjacent point, collectively spanning some larger distance. You just haven't been around that long, and frankly a lot of these questions are completely trivial for those who understand the code behind the simulation. I have been willfully blind to those things in general, just so I could feel like more of a scientist about it. Regardless of that, there have been endless discussions about just about anything you could imagine, which is why this forum has been so cool! This particular question is just something I never saw discussed before myself.

(Channeling Terry Jones) How is it that you have so few posts and yet are so knowledgeable in the ways of KSP?

I suspected that, but I was about to test it anyway with this: There's a docking port, a thermometer, and a barometer at the end, to test if atmo physics apply at that point and also to see if switching control points changes what happens. Don't need to bother with that now, thanks! I should have known that no such question would go unanswered for long in this particular community! So what does that mean? If you create a craft longer than 2.2 km, does the game just load the part that's within that radius of the root part and ignore the rest?

That's easy! Now rescuing a stranded Kerbal before you have maneuver nodes or RCS or the ability to set distant targets, that's just a little hard!

I swear that there was one time in some version that I actually found myself in orbit right after entering Mun's SOI, but it was probably some bug that happened near the boundary condition. As I understand it however, if you make a perfect entry into another body's SOI, i.e. you have no or nearly no motion as you cross in, you could in theory put yourself in a stable orbit for what amounts to an infinitesimal amount of dV.

@ColdJ Got it. The Jool dive is something pretty much every long-term player tries at some point, although it sounds like you pushed it to the extreme with that vessel! At any rate, I am now much more interested in the question of what happens if you put a ship half-in, half out of an atmosphere, and how far you can push that....

There has not been a post about this to my knowledge, but I've only recently become active on the forum again after a couple of years mostly away. If not, then I agree it could be an interesting experiment! I can't imagine that it would matter what body, but I'm also not at all above using alt-F12/HyperEdit to move such an experiment to wherever it needs to go. I think I'll have to give it a try this evening after I get bored with my endless Eve aerobraking passes.

What exactly do you mean by this? Just that you've dropped something by whatever means to 370m below datum on Jool and that's when it exploded? Or did you do something more interesting than that? I am actually kind of curious now what would happen if you placed such a setup in an orbit so that the command pod is always just above the atmo, but you can extend your arm far enough radial inwards that the tip is actually inside of it. Does the game treat the different parts of your vessel differently, or does it calculate everything based on where the command pod is? If it's the latter, then your arm wouldn't feel anything at all no matter how far you extend it, although the question of what happens if you extend the tip beyond physics range is still there. Surely somebody must have tried to build a station over 2.2 km long at some point. Any idea what happens @eddiew? @Turf?

I started with 0.18 I think, and I'd have to say that 0.9x still holds significant nostalgia for me. With no real aero model and all those massless-therefore-dragless parts, you could get away with the most ridiculous designs. Those were the days! I had this ion/Rapier-powered space motorcycle that could take off vertically and then single-stage it to just about anywhere and back. Made made mostly out of massless struts and positively plastered with massless OX-Stat panels, it flew with the most improbable efficiency. The same ship would be a total disaster today.

I actually want them to surprise me! I don't want it to feel like I've already played the game when it finally comes out. These little Dev teasers are plenty for me, almost too much even. ...and greetings fellow space chimpanzee! Has anyone talked to you about joining the union yet?

Roughly. My guess is if you extend the AP of the orbit you're on now by boosting purely prograde around your PE, you will hit Mun's orbit just a little before it gets there, but you should just try placing that maneuver node and sliding it back and forth a little along the orbit. If it does show you coming in ahead of Mun, then just right click on the node and push the little white "next orbit" button that's on the lower right. If that gets you (i.e. the arrows) closer, keep doing it until you see an encounter.

You are doing that maneuver too early and in the wrong direction. You should be boosting entirely prograde, and from that screenshot it's obvious that you're boosting a lot radial-out as well. Delete that maneuver node and place another one right at your PE, then carefully pull on the prograde handle to extend your existing AP to just short of Mun's orbit. If as I suspect that puts you ahead of Mun at your intersect, then wait one more orbit of your craft and try again.

I used to have the same problem with not being able to unlock my staging, regardless of how many times I hit Alt-L. What would fix it for me was switching to another vessel and then switching back. It ultimately ceased to be a problem for me because I finally learned first not to hit the staging button prematurely and second always to hit f5 before doing anything potentially dangerous. It seems to me that the latter of these things would especially help you, unless you have decided to start your KSP experience by playing a no-save hard career game, which is something even I won't try with thousands of hours of game time because of all the deadly bugs lurking where you least expect them.

There seems to be some confusion here. What it says on the top of your navball is your speed relative to the ground below you (surface), whatever you may have selected as your target (target), or the center of the body you are orbiting (orbit). You can toggle between those modes by clicking on the window where it says that, and for this purpose it should say "orbit". Low Kerbin orbit is a little over 2200 m/s in "orbit" navball mode, so you were probably looking there. If you make a maneuver node by clicking somewhere on your orbital path, the amount of deltaV associated with that will appear just to the right side of your navball. Anyway, to boost so you intersect Mun's orbit, you'll need to burn prograde to add another 850 m/s or so to your LKO orbital velocity of ~2200 m/s, so you'll be going a bit over 3000 m/s after you do that. I don't know how much dV you had left when you reached LKO, but if it was more than 900 m/s and now you're out of fuel, then you've overshot significantly, which means that your orbit goes well beyond Mun's, and although you may enter Mun's SOI at some point, you will need to do a significant amount of boosting with fuel you don't have to actually get into Munar orbit. So I would recommend that you revert that mission to the ground and try again, this time either placing a 850 m/s prograde maneuver node about 100 degrees behind the point in your orbit that is directly below Mun, or by just boosting prograde from that spot with the map view open and stopping as soon as you see yourself encountering Mun. To actuall make Munar orbit from there as cheaply as possible, you should set up your encounter so that your Munar PE is around 20 km and then boost retrograde when you reach it until you no longer see yourself escaping Mun's influence.

Echoing what others have said, move your engines down so they're not pushing you into the ground. Also move your rear wheels back so they're a little behind your CoM instead of in front of it, and displace your nose wheel a bit forwards and downwards, so your plane is pointing up a little. Rotating your wings so they're pitched up just a tiny bit would help too. You're still probably going to have problems with that very long tail piece though. I might replace that with a NCIS adapter full of fuel, which would also let you move your wings further back so they don't block your cockpit hatch. It would moreover let you move your rear wheels further back to reduce the danger of a tail strike on takeoff.

I assume the first of those has been done using props, as it seems eminently doable. Have either of the latter two actually been done? Again, I could envisage somebody doing the Jool thing with props, although that is one heck of a gravity well to climb out of, but Tylo and back in one stage seems really daunting. Perhaps if you do all your orbital maneuvers using Ions. I never had the patience for that.