Starhawk

Sweet! And that, gentle reader, is how we do that. Happy landings!

I long ago adopted the practice of always testing hatch and ladder setups on the pad before launching a mission. I had a ladder problem on Eve's surface once. And several obstructed hatches when I first started playing. Happy landings!

I was poking around a bit to find some posts I remember from the 'old days' and found this thread discussing the Oberth Effect. Just in case anybody wants a cool rabbit hole to explore. Lots of great discussion in there. Lots of math, too. Happy landings!

I think what's going on is a misunderstanding. Probably because I type too much when I get going. Your ejection trajectory in the 'Parallel Lines' pic isn't parallel to Duna's orbit. It is mostly downward, but it is angled to the left in the pic rather than straight along Duna's orbit line. I believe that's why your correction was so large. The longer orange line that is goes all the way from top to bottom along Duna's orbit line should be ignored. Only your ejection trajectory needs to be parallel. I have grabbed your pic and drawn where the trajectory should be for an optimal transfer. That greenish yellow (yellowish green?) line shows where the trajectory should be. So it should look more like this. Anyway, I hope that makes sense. With that, you should be able to make the course correction much smaller. Happy landings!

Thanks! That is, indeed, the one I use. It works great for me. Remember that the calendars between KSP1 and KSP2 are different by a year because there was no year zero in KSP1. I find that the movement is less jerky when I zoom in to the maneuver somewhat. When the orbit is a small circle on the screen, it's hard to get the maneuver where I want it. I spend a lot of time zooming in and out when planning a maneuver. Happy landings!

That should definitely not be happening. I'll look for that behaviour in my game. Happy landings!

This thread has been split off from the bug report since it has diverged sufficiently to be off topic there and it's a useful topic on it's own. Let me reiterate a point from my post above which, no doubt, got lost in the wall of text. You don't need to use the 'two burn' method to get home to Kerbin from another planet even with the bug. If you know the required dV and the date of the transfer window you can do the burn to get close to Kerbin return. Yes there will need to be a correction burn simply because without accurate trajectory prediction we can't fine tune our maneuver node to the needed precision. The key to all of this is the geometry of Hohmann transfers. A Hohmann transfer orbit for Duna to Kerbin just touches the orbit of Duna at one end and just touches the orbit of Kerbin at the other end. In terms of geometry, this means that your trajectory away from Duna should be parallel to the trajectory of Duna's orbit around Kerbol. Since you are going to a body in a lower orbit around Kerbol, you want to go in the opposite direction as Duna is moving. This does not take inclination into account, but inclination differences between Duna and Kerbin generally require only small course corrections. So if you know how much dV you will need and when to leave, you just place a maneuver on your orbit and give it the needed amount of dV prograde. Then, adjust the camera to be looking directly 'down' at Duna's north pole and then slide it around the orbit until the departure trajectory is parallel to the body you are orbiting. Grabbing the node to slide it can be a bit fiddly, but it works. This also requires zooming out a ways to see your result trajectory become almost a straight line so you can tell whether it's parallel or not, zooming in to make it easier to slide the node around in small increments, zooming out to check, etc. So a bit fiddly, but it works and should require only a relatively small correction burn to achieve/refine your rendezvous with Kerbin. Now on to the demonstration. Here is a craft in orbit of Duna. I overshot the optimal window for my 73 km orbit by about five days but that shouldn't make much difference. Looking 'down' at Duna's North pole. The faint red vertical line in the centre of the image is Duna's orbit around Kerbol. It is moving upward in the image, so we want to go downward when we leave Duna. Based on that, the maneuver should be somewhere around the periapsis in the above image. I make a maneuver node there with the dV reported by the external launch window planner, in this case 560 m/s. This is a little bit off from pointing straight down so I'll zoom in and slide the node around until I get it where i want. After a bit of adjustment it is pointing straight down along the faint red line of Duna's orbit. Now I go ahead and make the burn. Shortly after exiting Duna's SOI I make a maneuver for the course correction. A very small correction of 31 m/s gets me a nice tight rendezvous. An additional 5 m/s at the AN was used to tweak the inclination and that's that. The single burn (plus corrections) method cost 560 + 31 + 5 = 596 m/s Now for the double burn method. The burn to exit Duna's SOI from my 73 km orbit cost 357 m/s. The direction of this burn makes almost no difference because the point is that the minimum needed to escape the SOI is used and thus there is little excess velocity after leaving Duna's SOI. In any case, I burned to achieve the same trajectory as in the first method. After leaving Duna's SOI, the result is that I was in almost exactly the same orbit around Kerbol as Duna was, but just a bit behind it. I set up the burn to return to Kerbin and ran straight into the new behaviour of the maneuver tool. I can't see how much dV the maneuver will require because the craft does not have enough to get home using this method. 487 m/s are required to get as far as the image above plus the original 357 m/s to exit Duna's SOI makes 844 m/s spent and it still doesn't get the craft back to Kerbin's orbit. Not sure how much more is needed because of the change to the maneuver tool. So the double burn method cost 357 + 487 + ? = ? Thus 844 + ? = ? Anyway, even in Duna's relatively small and shallow gravity well the Oberth effect makes a huge difference. It turns out that this is not the case at all. Various bodies have false trajectory predictions that are off angle by varying amounts as seen in this post. Happy landings!

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Please tell us what you can about designing adventure mode. What has been the process of bringing a solid gameplay foundation to player progression in KSP2? Aside: You want the 'Colonies' milestone on the roadmap when the Orbital Assembly Building (or whatever it gets called) will appear. I look forward to that. Happy landings!

Excellent. Thanks for the tip! Happy landings!

This is an interesting discussion. I love seeing the creativity and thought that allows players to work around bugs like this one. Exiting a body's SOI with minimal excess velocity and then plotting a transfer to a destination from Kerbol orbit is a perfectly valid and useful method of astrogation. I do think it's a good idea to be clear about why this isn't done in real world space flight and what exactly are the upsides and downsides of doing it this way. Upsides: It's easy. This method is very simple and makes sense. Essentially you do things stepwise. Burn just enough to leave an SOI and get into a stable orbit of Kerbol. Then, create a maneuver to get to a destination. It removes the need for external planning tools. Once you are outside the SOI of the body you are leaving, you simply create a maneuver that makes your orbit just touch the orbit of your destination and then slide the maneuver around your orbit until you have an encounter. This process can be fiddly (and may require waiting for the ship to complete one or more orbits around Kerbol) but can be done without any external tools for finding phase angles or launch windows or required dV. It works completely around the bug. Downsides: It takes a lot more dV. This means, of course, a larger craft requiring more fuel. This likely means more stages and a more complex ship. It's not realistic. This is precisely because of the high dV requirement. IRL rockets are extremely expensive and complex to build. Engineers always work extremely hard to make everything as small and light as possible while still functional. I expect this is only a downside for some players. As far as downside 1., the question is 'How much more dV does it take?' The answer, as indicated above, is 'A lot.'. Let's see just how much. To do that, I loaded a save with a ship in 80 km Kerbin orbit, and set up a burn to reach Jool's orbit directly. I then reloaded the same save and burned just enough to leave Kerbin's SOI and then created a maneuver to reach Jool's orbit. Here's a look at the burn directly from Kerbin orbit. And here's a look at the 'two burn' method where I burned just enough to exit Kerbin's SOI and then set up a burn from Kerbol orbit to get to Jool's orbit. So, the single burn from Kerbin orbit requires 1960 m/s of dV to get to Jool's orbit. The 'two burn' method requires 939 m/s to leave Kerbin SOI and then another 2538 m/s to go from near Kerbin's orbit to Jool's orbit. So 2538 + 939 = 3477 m/s total. That's not quite double, but it's way more. Why does it take so much less if we make the burn in low Kerbin orbit as opposed to in Kerbol orbit? The answer is The Oberth Effect. This is a fairly math heavy concept, but the upshot is that fuel burned prograde (or retrograde) while moving at a high velocity low in a gravity well gives you much more 'bang for your buck' than fuel burned prograde (or retrograde) moving at a low velocity high up in a gravity well. That's not a great description and I'm sure somebody more knowledgeable could come along and give a much more accurate description. But it's enough to convey the basic idea. It is still fully possible to use the more efficient Hohmann transfer (the first method above) for all interplanetary burns right now. You simply have to know which direction you want your trajectory to go compared to the orbit of the body you are leaving, know about how much dV you need to burn, and know when to burn. You also have to ignore the trajectory line displayed until after you leave the SOI. Happy landings!

I would really like to see a screenshot key implemented. While I know that there are many Steam players and Steam has it's own screenshot key, it would be very nice if there was a dedicated screenshot key for those of us who are non-Steam players. Happy landings!

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@RubenioThe ISP of a rocket engine varies with the atmospheric pressure surrounding the rocket. That's why you see two ISP numbers in the VAB for a rocket engine. One for vacuum and one for one atmosphere of pressure. ISP increases with lower pressure and decreases with higher pressure. The behaviour you are seeing is expected. Happy landings!

Since this seems to be a tutorial rather than a Gameplay Question it has been moved.

With your workspace loaded, click on the icon for opening a workspace. Then simply select a workspace and click 'Merge' at the bottom. Happy landings!

Hello @TheBlackJackal and welcome to the forum! I'm glad to hear you are enjoying KSP2 so much. As to your question there is only one answer for that. Snacks! Happy landings!

I managed to get the Dubious 2 to orbit today. The big tanks feeding the mammoths are almost dry. There may still be enough dV to try a Jool 5 mission. Maybe. Happy landings!

But this is not the case. I've played with a couple of LS mods and that only changes the ship design a little bit. The gameplay is exactly the same for me other than that. Add some food, water, and air modules and away you go. I don't strand Kerbals, but I don't feel the need to add 'realism' factors such as launching to the Mun while I'm waiting for that Jool mission to arrive. This is exactly the sort of realism that completely kills the fun for me. I have no interest in mimicking the commercial spaceflight industry. I have no interest in 'wanting to get hired'. Happy landings!

Time is an interesting thing in KSP. It seems to me that different players can think about time very differently. In KSP1 when I wanted to do a mission to Jool or Eeloo I didn't worry about the time passing as I was time warping to get to the transfer window and then warping years between course corrections on the way there. That's the game to me. Others seem to feel compelled to fill that time with other launches and activities closer to home. For me, that just delays progress on the mission that is my focus. So I don't do that. Imagine what it might be like when flying one's first interstellar mission. I can't see trying to do local missions while you wait for your interstellar ship to arrive. It seems to me that it would never happen. The time scales are so vastly different for interstellar that it seems to me there is no choice but to time warp for longish periods or the mission would never arrive. It follows, then, that any kind of colony life support would need to be completely hands off once it is set up. I can't really imagine it being fun for me if when trying to time warp my interstellar ship on my first mission to a new star system, repeatedly have a pop-up which drops me out of warp saying something along the lines of 'Colony X is almost out of food!' or something like that. On the other hand, it may well be that there are some who would like to play like that. Maybe you have to drop out of time warp to tweak the settings on the greenhouse for your colony ship or something along those lines. Perhaps that appeals to some players. One thing I know about this game is that there are a lot of different ways people enjoy it. Happy landings!

This report of a bug has been moved to bug reports.