Wobbly Av8r

There's a really good tutorial on the front page of the forums but I'll repost it here... This should go a long way toward helping you figure out them props and blades... There was also a post, IIRC, about using props and blades but I can't locate it now - if I do, I'll post that link as well.

That all reflects my experience and what I've settled on - it is good to know that others are looking at the same type of thing and coming up with with similar solutions. (We may not be right, but we are in agreement!) Still, any idea where/what the "transfer" information means as regurgitated by KER relative to such an orbit? In my example, which after a lot of contemplation of efficiency requires the same approach you took, what event would occur in 28 days that is meaningful in a "transfer" sense? Again, any ideas are welcome!

Well, I was gonna say straight out no, but reconsidering that Eve's year is ~262 days, maybe? I don't think it would help me catch it in the optimal location (making the assumption that the optimal is when it is closest to Kerbin's orbital plane) but it could sling shot me to help catch it... I'm pretty sure Jool is a no from what I can see.

I hear ya, @domendemo. Docking is an exercise in patience, no doubt. It's common to want to speed up when you have a fairly large distance to cover during the approach phase but, of course, you encounter the "where are the brakes on this thing?!?" sinking feeling as you realize your RCS system is no match for the speed component of inertia !! I've found that having an accurate readout of distance to closest approach and time to closest approach (like the Kerbal Engineer Redux mod can give you) is the best way to handle those loooooong approaches - rather than increase the velocity of your vessel, and knowing that after your initial RCS burn will place you to within, say 100m of your target... in 4 or 5 minutes or longer... then speed up the simulation (physics warp) while monitoring how much time is left to go (with the "." key). It really works best when you know how much time you have to go as well as how far apart you'll be when you're at your closest approach. If you give it a whirl, you may find that RCS TWR is usually not an issue at all.

Long story short: I picked up a "Go get a comet sample" contract and found it was not the animal I thought it was. I was hoping to get it done in the usual "asteroidal" time frame of ~100 days or so but it's beginning to look like a minimum 5 year venture, which is, well, more realistic but a pain to have that open contract for such a long time (BTW, Thank you Kerbal Alarm Clock!). So the scenario is depicted below with some of the orbital info listed. If I'm missing something about what I *think* is the best way to do this, please share your knowledge with me! My take on the matter is that, due to the comet's 7 degree relative inclination, I will have to intercept either the comet (best) near the Kerbin orbit DN, or the join the comet's orbit inclination at the DN (which basically coincides with the comet's Kerbol Pe and is 92 days out) and chase it, i.e. wait for it to come around again. Unfortunately Kerbin is 208 days away from that DN so to meet the comet near DN on THIS orbit would require some creative retro-Kerbin burn that lets me "cut the corner" but would of course require a mid-course correction at some point to rejoin on the other side. Any way I've calculated this, we're talking 5000+ dV requirement not to mention my relative velocity at approach would be around 1500 m/s, which is no bueno. While trying to figure this one out, I'm seeing that Kerbal Engineer Redux, with the comet as the target, claims I have a "Time to Transfer" in 28 days (as well as a transfer angle of ~77 degrees...) and seeing as how I can't even figure out how to catch up to this comet NOW, I'm not sure what this calculation means, if anything, especially because my target is in a non-circular and crossing orbit. I can't figure out an efficient way to catch this comet (total of <5000 dV? Or am I smokin' crack?) without waiting the 208 days to leave Kerbin and enter into the identically inclined comet's orbit followed by a small adjustment burn to time the meeting when the comet comes by again in 5+ years. Is this typical? Did I miss something here? If KER says I have a transfer window in 28 days, what is this based on? What kind of a burn would I be looking at in 28 days that would improve my ability to "transfer" to this comet before my Kerbals retire? And finally, any suggestions for chasing comets (other than I shoulda' looked at the contract a little more carefully) would be appreciated!

Great ideas and information already from the posters above, so I'd only want to add some other thoughts on the matter... While I believe SSTO's to be the hands-down winner of the reusability contest, they can be a 'handful' to operate successfully... repeatedly through recovery... with differing size and weight payloads. And most importantly they lack the majesty and projection of sheer power that accompanies a full-on Rocket Launch (tm) !!! So what I guess I'm trying to say is that there are a number of ways to skin this cat (no cats are/were harmed in the making of my Kerbal Space program). As an example of a compromise, my favorite is a core reusable booster that can be supplemented with various SRB's (unfortunately -but necessarily- disposable) to accomplish placing various payloads into LKO - for instance, I can place 18 tons into LKO for a total cost of less than 7,000 kerbucks, and using SRB's, place 42 tons into LKO for less than 21,000 kerbucks. De-orbiting the booster can be done 'at my leisure' which enables me to not only deal with the primary payload's trajectory in a timely manner, but also allows me to maximize recovery costs by de-orbiting such that touchdown is close to KSC. And this type of reusability demands much lower 'maintenance' than dealing with an SSTO. (While I love the idea of @Boyster landing the booster back at KSC similar to Space-X's ventures, it would require much of the 'maintenance' of an SSTO to recover accurately, while the ability to toss out a couple of 'chutes and not be choosy about whether you'll be on land or water near KSC is worth the trade-off to me...) Just food for thought.

And if Santa Kerbal (Santa Kerman?) ever grants that wish, these forums will become a ghost town!!!

A quick (but probably unsatisfying) answer is that what you are looking for is "Ascent Guidance" rather than Aircraft Autopilot in this specific case. The "Ascent Guidance" module is, of course, a ways into the Tech Tree to unlock. A good way to experiment with MechJeb2 is to build a "Sandbox" game with everything unlocked, build a vessel and then experiment with it. In your example, you'll find that setting the Inclination to 40 degrees will result in a heading of 50 degrees true, while an Inclination of -10 degrees will result in a heading of 100 degrees True. Hopefully that makes some sense... @VoidSquid Amen, bruh.

Thanks for that suggestion and link - I'll take a look.

Isn't the spirit of KSP and its community about getting around arbitrary limitations through innovation and determination? It's not like the fidelity of the simulation is violated by doing on Kerbin what is done in space! While hoping that there is/was some "backdoor" method of getting around this, what is obviously achievable in orbit must certainly be achievable in construction, right? Maybe someone with some familiarity about the .SFS save file and/or the .CRAFT files can suggest a procedure to cut & paste sections/values to mimic what is assembled in space? [ Edit: Perhaps someone can guide me toward where I can find out more about the coordinates / values in the .craft file and how they translate into the values one see's in the .sfs file? What are the pos, rot, dir, and col values? (I assume they mean position, rotation, direction and column but have no reference for the context of the values) Also variables attPos, attPos0, attRot and attRot0 ]

Looking for Kerbonauts who have experience with the KAS (Kerbal Attachment System) mod... or anyone who might know any KAS-part attachment tricks... I'm attempting to use the TJ-1 Fixed Telescopic Joint and connect it to a JS-1 Joint Socket... while still in the VAB during initial construction. I have had no problem doing an EVA and accomplishing the task as they were designed to do, but I would like to use the same parts in the construction of a vessel in the VAB but can't find a way to attach the TJ-1 to the JS-1 during VAB construction. In the image below, on the left is the VAB construction which apparently won't allow me to connect the two designed-to-be-connected parts that, on the right, are relatively straight-forward to attach/connect during an EVA in orbit. Thanks in advance for any ideas or suggestions!

The space shuttle is a unique arrangement for thrust vectors and changing center of mass throughout flight. While I'm sure there are a number of workable solutions, the one I stumbled upon was to reduce thrust on the shuttle main engines to 50% throughout flight, reduce the amount of fuel in the solids as well as a peculiar arrangement of fuel tanks within the main tank that alter the center of mass in a manageable way as fuel is consumed. You can download it and take a look if it helps - https://kerbalx.com/Wobbly_Av8r/Space-Shuttle-with-Boosters If you have MechJeb, in the ascent autopilot window, set Limit thrust to 50% (the solid's are preset to 80%) and set Force Roll Climb 90 turn 180 and a 40% gravity turn profile and set desired altitude about 75,000 m. I suggest enabling the aerodynamic forces overlay (default F12) and observe the amount of control force required to maintain the profile, particularly the shuttle elevators and the relationship to the changing center of mass of the main tank. Adding up to 750 units of ore in the ballast tank of the main tank helps to dampen the rotational movement of the main tank but, of course, reduces overall performance. A couple of additional actions that will make the flight more 'pleasurable': manually stage the main tank separation after main engine cutoff / coasting phase has been established (but before the circularizing burn) - turning on RCS before doing so dampens rotational forces. Keeping the RCS on for the circularizing burn is essential as well due to the offset thrust of the orbiter's engines, and (finally) you may need to take the controls from MechJeb right near the end of the circularizing burn because MechJeb likes to micro-adjust the burn rather abruptly which can aggravate the very delicate balance of thrust and center of mass of the shuttle! [Edit: Here is a link to original post re: shuttle flipping... ]

All the previous responses are certainly in agreement with my experiences in KSP, but I would suggest you take it a bit further and explore where the drag on your design comes from - you'd be surprised. Using the 'Debug Menu' (same access as 'Cheat Menu') there is an Aero tab - activate the option "Show aero data in Parts Window" or something similar to that - you'll see a new ">Debug" tab attached to the PAW's which include drag information. Regarding what you're looking for here, there are a few rows of data that begin with "YP" and "YN" (Y-axis Positive / Negative) - these values are the exposed portion of the drag cube described by @bewing and @Lt_Duckweed above. You'll be surprised at where your vessel's drag might be coming from - parts that "look" like they are streamlined may literally look like a large, draggy, flat plate to the game's physics engine; if care is not taken in construction (and sometimes certain parts properly installed are still VERY drag-intensive) it can result in problems that are mystifying and frustrating. The blunt mating surface of a large fuel tank can cause aerodynamic mayhem - even though it "appears" to have some form of aerodynamic streamlining attached to it. One word of caution when activating this function - deactivate it before returning to the VAB / SPH as keeping the option available during construction can cause performance stutters that make it almost impossible to build / modify anything in the VAB.

LOL! Yeah - as I was posting I was pretty sure I'd seen in somewhere in the stock game but couldn't remember where since I gave up using it for the ease and robustness of KER telemetry.

My go to for this task is Kerbal Engineer Redux - under the tab of "Surface" you can select it to display what biome you're over as well as "Impact Biome" if you have a suborbital trajectory. More importantly I find it critical to give what is essential information such as slope of the terrain you're approaching and the "Impact marker" is highly useful. If you're hostile to mods, there's always the maps that are published for each body and its biomes - you'll have to match land structures / craters and plan on where you'd like to plant it... er, I mean, land!

While I was unable to cheat a vessel into that orbit, what your results tell me is that the orientation of your orbit prevented you from slowing your orbital velocity around Kerbin. Using your 525 dV to minimize time to Kerbin would require that the plane of the orbit around the Mun allow the KOI (Kerbin Orbital Insertion) to leave the Mun's SOI in the most retrograde manner possible; the most efficient orbits are those that pass through or close to the Mun's retrograde 'node' in its orbit around Kerbin. In an equatorial orbit, this position occurs once every orbit while the more inclined the orbit, the further from this point you move as the Mun orbits Kerbin resulting in a less and less efficient burn - unless you wait until the combination of your specific inclined orbit and the Mun's orbit around Kerbin RESULT in an position that passes through or close to the Mun's retrograde node. So time, then, is relative - burn now (in some arbitrary position) and take a long time to travel to Kerbin, or wait an amount of time until your orbit relative to the Mun/Kerbin allows the 525 dV burn to produce the most efficient trip betwen the Mun and Kerbin. Either way, you're gonna need time to overcome your inclined orbit within a dV budget.

Sorry - wasn't aware of the console limitations, but even if you have to transfer to a tank or two you didn't want to, then transfer the fuel from those (fewer) tanks to where you want might still be quicker.

If you select the resources icon (looks like a drop of liquid on a gas can, upper right) it will show the current level of your consumable resources - liquid fuel, oxidizer, monopropellant and electricity. After selecting that icon so that the display remains on the screen, click the check box next to liquid fuel and ALL of your tanks' PAW (Part Action Windows) and fuel levels will become visible. Find the one which you wish to transfer FROM, click the OUT button and it will transfer its fuel to all other tanks. If there are tanks you do NOT want to transfer to, pin the ones you want fuel into and uncheck the box you checked in the resource window so the unpinned PAW's will disappear. Only the tanks whose PAW is visible will receive fuel. Maybe not exactly what you are looking for, but definitely shortens many transfers....

From the "A picture is worth a thousand words", a .craft file has gotta be worth at least a few lines of explanation.... https://kerbalx.com/crafts/64413 Check it out in the VAB and you'll see some things that needed to be done to keep the fuel balanced and if you set it up with MechJeb like I have in the image below, it'll give you a pretty nice hands off flight. As the SRB's separate you'll see that the Orbiter is at max control deflection to counteract the SRB's, but is then brought back into full control as the SRB's burn out. Turn on RCS after the Orbiter completes its burn and awaits the circularization burn, also manually stage the main tank after turning on the RCS (it helps with the rapid change of CG). Limiting the throttle to 50% helps to allow the reaction wheels to stabilize things since the thrust vector relative to the CG is not quite aligned. Re-entry only requires that you keep the nose up around 45 degrees and wings level as you descend from 45km down to 25km and then slowly lower the nose to "Lawn Dart" position around 20 km and land it.

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Not trying to presume anything with regard to your experiences, but it usually takes less than 100 dV to leave a Minmus orbit to escape Kerbin's SOI, compared to ~4300+ for Kerbin; the Mun and Minmus are similar in advantage with the main difference in orbital period (how long it takes to get back to a specific postion with the Mun 'winning') and extra dV to both establish the orbit and then leave it again (with Minmus 'winning'). Once outside of Kerbin's SOI you have the orbital velocity of Kerbin around Kerbol (9,000+ m/s), give or take, to go/do whatever you want. Many folks want to think of Minmus as a tall mountain on Kerbin that they can jump off of to other places but are stunned when they encounter the issues you have; the key to using Minmus is to understand that you have to FIRST escape Minmus' SOI and THEN escape Kerbin's SOI. Attempting to do both in one burn, depending on where you're going AFTER the burn, can diminish or completely remove any advantage you might have had operating from a Minmus orbit. There's a saying among pilots that there are old pilots and bold pilots, but there are no old, bold pilots. The same could be said about space travel - there are quick solutions and there are efficient solutions, but there are no quick, efficient solutions; here you are faced with the potential of two burns - maybe 30 days apart - to leave Kerbin's SOI from Minmus orbit efficiently or some much, much higher dV burn to leave Minmus' SOI, enter Kerbin's SOI in a disadvantageous position in which you cotinue to burn inefficiently to escape Kerbin's SOI. It's similar to launching straight up and then making a 90 deg turn to establish orbit vs. a gravity turn.

It's one of the 'charms' of KSP that it hands out contracts that may be damn near impossible (well, nothing's impossible in KSP but you get my gist...) but some folks like a challenge so most players quickly establish an understanding of which contracts will help progress their game and which contracts will end up giving them an aneurysm... (I'll leave the classification to you on chasing this comet) There are definitely harder and easier ways to make Kerbucks... The short answer to your question... ...is that when two objects orbit a common body, yes, at two points the PLANES of their orbit will cross. For adjusting one body's orbit to another, THAT is the most efficient spot to make that adjustment but that doesn't mean YOU are any closer to the other object - just at the lowest dV plane-adjustment point. The orbital plane of Kerbin crosses the orbital plane of Eeloo twice per orbit, but that doesn't mean you're any closer to Eeloo after a plane change than when your were sitting on the Launch pad. Because comet orbits are highly eccentric and inclined, they seem to be more "in reach" but in general, the possibility of capture is in the timing of the closest approach rather than a "transfer window" as it applies to other bodies orbiting Kerbol. Launching into the proper inclination is one thing, pushing the Ap out efficiently to make contact is highly dependent on the relationship between Kerbin's orbit and the comet's position relative to that orbit (meaning time of year) - IF you're on a "dV budget". [ Edit: After reviewing my posts for clarity, I may have insinuated that the Launch itself is critical to all intercept orbit aspects, but it is not immediately critical to time-of-year, as that aspect of the intercept can be most easily dealt with by performing your "push out" burn at the correct position/time-of-year after establishing the proper inclination and orientation (longitude of ascending node) around Kerbin, i.e time your launch so that the initial orbit itself is parallel to the comet's orbit and maintain that until Kerbin's orbit around Kerbol places your orbit in the same PLANE as the comet's. Hope that clears it up... ]

One way to think about what's happening is that once you 'pop out' of Kerbin's SOI, you are *IMMEDIATELY* in Kerbol's SOI with all of the properties of Kerbin's orbit around Kerbol which have become your vessel's, plus or minus whatever you were doing around Kerbin. As a result, the dV requirement can become extreme to alter that path. The low-dV solution to this is to not only launch with proper inclination at time-of-day but time-of-year as well (when the arc of the comet through Kerbol intercepts Kerbin's orbit around Kerbol). [ In many cases you may not be able to launch at the optimal time-of-year, but in doing so you have to recognize that the dV requirement increases proportionately ]

Love the planning and approach to the problem, @takethecake !! I would highly recommend launching directly into the correct inclination rather than adjusting to it in LKO (Low Kerbin Orbit); this is a combination of time-of-day as well as actual inclination for your target. [ The path of the comet creates an arc which 'slices' through Kerbin - you must wait until the Launch site is located upon that 'slice' before launching into proper inclination ] In general, for most orbital mechanics-type problems, the range of solutions vary from quick & expensive (high dV) to slow & efficient. I don't have your situation in front of me, but when I've undertaken these kinds of ventures, in order to do it within reasonable constraints has required a lot of very specific timing to eliminate the extra dV's required to adjust for more random timing. As an example, for an asteroid intercept mission, I've first launched a probe into a very specific inclination that aligns with the asteroid's path passing Kerbin and then waited for 50+ days to "push out" into an orbit that would allow me to capture the asteroid on the trip back TOWARD Kerbin and Kerbin Pe to minimize velocity differences, keeping in mind that the closer you can orient your vessel's path to that of your target at intercept will allow for a greater disparity of velocity to be compensated for. Hope that helps...

From what I've heard from others, if you put more Sentinel's in proper orbits, the more chance you'll have of the game spawning comets.