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king of nowhere

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Posts posted by king of nowhere

  1. 33 minutes ago, Dungas Kerman said:

    Well I had a lander and a mothership so I have two mk3 pods. One with just a mk3 pod, heat shield and parachute, and the other the same but with an extra lander can underneath the mk3 pod (oh and 4 radial drogue chutes). 

    In my first attempt I tried staggering the reentry so that I had more than 1 hour in between arrivals. That was easy enough since I've done it many times before without problems. The first pod to arrive was hitting Kerbin with a periapsis of about 21km and burned to a crisp before it even got there. I didn't bother trying the second one since I want all my Kerbonauts to survive and it is coming in at a similar speed anyway.

     

    Here is a screenshot of what I'm working with. 

    https://ibb.co/nb3PQGF

    I would expect that lander can to be the weakness in this but oddly enough it's not. Its heatshield overheats and is detached before the lander can explodes so it really looks like it's just the shield that can't take it.

    those kind of reentry pods are the most resistant available. the mk2 lander pod can be a weakness, but you say it doesn't explode first, so it is fine against my every prediction.

    but i see the problem: 21 km periapsis. way too low here. you get inside the denser atmosphere too fast. high speed reentry is a delicate balance, you have to stay as high as possible in the atmosphere to reduce heating, while still be deep enough to get captured. if the height required to get captured is lower than the height at which you explode, there's when you can't get a capture.

    I once managed to save a high speed reentry by raising periapsis by a single km.

    I suggest trying with 35 km periapsis first. that should be enough to capture safely. if you still explode, try 36 km, and so on until you don't explode. if that minimum level to not explode is not low enough for capture you're screwed, but it really should not be your case. in fact, eyeballing it i'd say the smallest pod should be fine anywhere between 30 and 40 km. the one with the lander can may be harder to land

  2. 9 hours ago, Leganeski said:

    If you need to recover two crew capsules, consider sending them down separately at different times, each with their own heat shield.

    to expand on that: you can only control one object at a time, and a ship going deep into the atmosphere and outside of physical range of the vessel you're controlling is authomatically deleted.

    if it's not deep enough to be deleted, it will just move on without braking. in both cases, you lose it.

    so you must separate your two pods and ensure they enter atmosphere at 20 minutes distance from each other.

     

    if you can't find the problem, post pictures of your crew pods. 5 km/s is survivable, maybe there is some problem in the design

  3. 10 hours ago, Leras said:

    Hi! :p

    I have a little problem with missions

    Example: I have a mission to get a mun stone but when my kerbal get a stone mun and back kerbin the mission continue incomplete

    And another mission i get a temperature over some place, over flying surface, what is the limit the "over flying surface"?

    Sorry for my bad English

    Have a Good day

    the mission generally specifies additional conditions. open the mission menu and you should see, for example, the altitude requirements for "flying over"

    as for the mun stone, i'm not sure but i suspect maybe it wasn't stored properly and got discarded instead

  4. you must ignite the engine as the test.

    if the engine was already ignited, then it won't count for passing the test.
    i can't really tell from your images, but my impression is that you was already using the poodle and terrier - as evidenced by the fuel being partially empty. this won't do; you have to activate them when you have the conditions for the test, not before.

     

    if it's not that, then i have no idea

  5. Part 14: Making fuel in hell

    A'Twin goes to the binary system of Pluto and Charon, named after gods of the underworld.

    The names prove accurate, because the bugs involved in refueling were staggering.

    Asg6exe.png

    Pluto and Charon seen from the cupola

    14.1) Going to Pluto is easy, leaving Uranus is hard

    Spoiler

    Picking a trajectory for Pluto turns out to not be too hard. Or, well, the main difference with my near disaster on Plock in the OPM grand tour is that back at the time, I was required to be able to return without refueling; this time, I know I can refuel on Pluto and I plan for it.

    A proper Hohmann transfer would take over a century, but there are pretty cheap trajectories also for lesser durations.

    eH9D226.png

    A low energy transfer to Pluto, requiring little more than 3 km/s (mostly to leave Uranus gravity) but 70 years

    Seventy years are within A'Twin's life support capability, barely. Still, I have 8 km/s and as usual I try to save time. For the same reason I am launching immediately instead of waiting 7-10 years to pass exactly on the planar node, even though that would be cheaper.

    Turns out, the main difficulty is actually leaving Uranus. Not only the moons rotate shifted by 90 degrees compared to the ecliptic but right now their plane is also pointed in the completely wrong direction. It's hard to describe and I don't have the necessary skills to draw it, but if the plan of the moons passed closer to Pluto, I could still use the moon's motion to eject prograde at a reduced cost. Instead, that plane is passing near the sun, so no matter when I pick my ignition, I can never get a prograde motion relative to the sun.

    Another major difficulty is that sometimes I make an additional maneuver node for a correction maneuver, just to see a close approach to Pluto, and when I don't need it anymore, I can't delete it. Clicking on the X on map view does nothing, clicling on the X on the box in the bottom left of the screen crashes the game. I add it to the list as bug #38, though it's been plaguing this mission on occasions for a while. I learned that the best way to deal with it is to leave the maneuver node, but reset it to 0 m/s so it won't interfere with whatever new trajectory I'm planning.

    Ultimately, I decided to just leave Uranus and make the burn in interplanetary space. It's less frustrating this way.

    ye13rjh.png

    Trajectory to Pluto

    So I'll end up paying 1140 m/s to exit Uranus' sphere of influence, then 2200 m/s evenly spread between normal and prograde at the planar node ten years later to match inclination and get away from the sun, arriving at Pluto 40 years later with 2 km/s intercept speed. Total cost is 5 km/s; fully fueled, A'Twin has between 7 and 8 km/s depending on the order of use of nuclear and chemical engines, leaving 1 km/s to land on Pluto and 1 km/s for any emergency.

    If I had saved more out of the fuel budget, I'd have used it to get a faster trip.

    Forty years in space. Requiring yearly maintenance on the reactors. The later part of this mission is a real slog. Having to fix the ship is not a big deal in the inner solar system, where you plan trajectories, land somewhere, and in the middle of it all you perform maintenance once and it's all part of the fun. Here I do nothing but maintenance. At least I can thank bug #15 for not having to service the rest of the ship too.

    tQUvBuq.png

    I'm trying to get pictures of A'Twin from unusual directions, for the sake of novelty

    By the way, one of the remaining six reactors was also struck by bug 15, and doesn't need upkeep anymore. But I'd rather keep more than a single working reactor.

    This time forty years - 38 plus three and a half months, to be accurate - go smoothly. No malfunctions, not even fixable ones.

    nlO6LDt.png

    Arriving at Pluto, still with half my water available. Also with half the nitrogen (stored as monopropellant), that was last restocked 120 years ago

    Now, I said that I had to land on Pluto - despite being bigger and heavier and having no uranium - because Charon had no water. Well, I was wrong. I annotated ore availability in a confusing way, and then I misread it later. Turns out, Charon has water in every single biome. I looked it better, and found a tiny biome near the equator with high concentrations of all the three resources I need. Yay!

    u0sPScq.png

    New trajectory for Charon

    So I'll get captured in a trans-Charon injection orbit. I also dumped most of the oxidizer that I planned for landing in higher gravity, and most of the uranium that I planned because Pluto has no uranium.

    XHBJEQ6.png

    Servicing the engines around Pluto

    14.2) Forever a planet in our hearts

    Spoiler

    A'Twin will spend 3 days in its current elliptic orbit waiting to meet Charon; a perfect time to send Clamp to land on Pluto. Clamp's deltaV is also barely enough to land and return from its current orbit without needing Fat Man.

    By mission procedure I should not send Clamp alone in case of life support malfunction, but what the hell, it's been almost 300 years, what are the odds that a malfunction will happen in the next 3 days?

    xg5tGCj.png

    Bug #17 is still active, so Rudatte must still take the rough ride

    vTQDiPj.png

    Landed

    At this point, since I have 3 days to pass anyway, I decide to drive around a little bit. Actually I was surprised that I could drive at all, Pluto is very similar to Triton, including an identical atmosphere, and I worried it had the same terrain bug (#36). Everything is fine as long as I go straight, but while braking I lost control and tumbled around. Having the two reaction wheels broken make the rover sluggish, and I can't send out Peretto to fix them. The rover survived, but the front docking port hit hard and exploded.

    That docking port was the one struck by bug #26, and I would have removed it if I could. So, it's actually a good outcome! I did try to explode the offending docking port in the past, since I could not remove it manually, but it resulted in crashing the game.

    1sadNOK.png

    Clamp without the frontal docking port

    No, this did not magically fix also bug #17. On the plus side, I shouldn't need Clamp ever again.

    twOZ5AD.png

    Back to orbit

    cCEc4MS.png

    Return to A'Twin, with very tight fuel budget

    Now, I may have been very optimistic on the cost of this landing, or perhaps I was wasteful. But I need a 206 m/s burn followed by a 99 m/s intercept, for a total of 305 m/s, and I have 307. I already optimized as well as I can.

    MllhMTJ.png

    Clamp rejoining A'Twin, which is below the sun in this picture

    6WHyQlV.png

    And the same in natural light; A'Twin is actually more visible, due to being backlit and shilouetted. The surface is still lit well enough

    DvizdNT.png

    About to dock, with 1 m/s left. That was close

    Ok, if I had run out of fuel I could always move A'Twin, not a big deal.

    IdlvQ4U.png

    New bug #39! Those colored lines have been appearing on and off when I moved past the orbit of Neptune, but this is the first time I get to take a pic

    Bug #39 had me worried, but it looks like a harmless visual glitch. At least, it disappears as randomly as it appears, and the game keep working.

    Speaking of bugs, this whole mission is always on the verge of crashing. Whenever I open the debug console, I see this.

    drM8Nur.png

    The debug console; I have no idea what any of that means, but all that red can't be a good sign

    I haven't included that as a bug in the list because it's more of a notification of bugs.

    Anyway, without further excitement I reached Charon.

    14.3) I'm Charon, and I'll ferry you to hell

    Spoiler

    The place I'm supposed to land in is called Butler Mons, though it looks more like a crater. It's quite small, but still big enough to be easy to pinpoint.

    TQgmbHi.png

    The landing zone, and status in orbit. Still plenty of fuel left. I dumped most of the water because it's useless mass now, and I'll find new one soon

    GutfZyv.png

    Landing. It's been a while since I last used this inner perspective

    In fact, I tried to land using only the inner perspective, and I ended up falling on a side.

    ZALzYqA.png

    The landing zone is almost underneath Pluto

    E9RRVjx.png

    Landed

    Now refueling operations can start, bugs allowing. I already see bad signs.

    qdIb3nv.png

    Charon has a terrain bug. See how deeply the landing struts sink into the ground

    This looks like bug#24, the game being confused on where exactly the "ground" is.

    And I expect this to also glitch with whether a drill is properly inserted into the ground, leading to bug #7.

    JcVERrn.png

    Indeed, here's bug #7

    sQDXGfr.png

    And just to add, on Charon there's a high chance that A'Twin will randomly explode. Like this

    I realize I don't have any specific entry for "ship explodes when loading the game", but I guess it can be considered a more extreme case of bug #2 or #9, with the detached/mangled parts clipping into each other and starting explosions. It's normally rare, but on Charon it's been happening roughly half the times.

    s8lhPaY.png

    Kr6Mld6.png

    Rg0kdTW.png

    Some of those explosions were quite spectacular, like the one in this sequence

    PpfnVD1.png

    Went to service the reactors, took the chance to plant a flag

    By the way, science experiments when I fly around the ship with the jetpack report as "space high". This mountain/crater isn't high at all; I wonder where space low is on this moon.

    Ore concentration is above 9%, like on Iapetus. I mine ore very fast, the limitation to how quickly I can refuel is the process to extract carbon from the ore; it's very energy intensive, and I only have 6 nuclear reactors left.

    P2DsXzo.png

    A screen to detail isru speed

    I managed to use my available electrical power to the fullest; the reactors are producing 18350 electricity/second, when their very maximum is 18360 (3000 each for the six big reactors, and 60 each for the small reactors on Cylinder). I am making 4900 liquid fuel at *1000000 time warp - it was less than 2000 on Titania. Earlier on Iapetus I got at high as 7000, but I had more working reactors back then.

    So, if on Titania I refueled in 11 years, I should do it in slightly more than four years on Charon. Except that bug #7 is in full swing, and A'Twin spends more time failing to mine than it spends working correctly.

    2Z11RJj.png

    Just a good picture of the landed mothership with Pluto in background

    One year passed, it's time to again service the reactors; of course I wouldn't even mention this routine operation except that something is about to happen.

    2Yygsro.png

    New bug #40! Peretto explodes in midair!

    While gently flying mid-air, the game suddenly decided Peretto had sunk on the ground, making him explode in a cloud of smoke. This is troubling, because I need to service those reactors.

    I tried reloading, the bug kept happening in the same way. I tried moving Peretto to the cupola and send him out from there, the bug kept happening. I tried to reload back a couple saves, the bug kept happening.

    YcsWwU6.png

    Also, reloading made the ship explode again

    NlGEYD2.png

    But hey, at least Peretto could make it to the ground this time!

    Since Peretto was able to land, maybe this save is not afflicted by bug #40? I reloaded again, this time the ship did not explode, but Peretto did.

    I thought maybe the responsible was ground tether (a function I just discovered to stop a ship from sliding on the ground, because I was having the same issue I had on Vesta back in 6.4), but it made no difference.

    Having exhausted other options, I did resort to extreme means. I used alt-f12 to move A'Twin in orbit. There I serviced the reactors, without any ground problem. Then I alt-f12 the ship back in place; I actually managed to "teleport" it within 150 meters of the original flag.

    CaQ5Ear.png

    Nine years later, refueling is done. Status before leaving

    What? You were expecting some more bugs? Wasn't that enough?

    Remember, it should have taken less than 5 years without bug #7; but despite all, it's still been faster than on Titania. And nothing broke.

    The grand tour is almost done. Now I need to return to Earth. I can make the trip in a reasonable time, but I will have a high intercept speed. So my plan involves going for Mars first, to refuel on Phobos... wait, if I have enough fuel to capture on Mars, shouldn't I have enough also for capture on Earth, with greater Oberth effect compensating for higher orbital speed?

    Yes, but I still miss two landings. I landed on the Moon twice, but both times I had to restart the mission. In this save continuity, I never did, so I will have one last mission for Spider. And I never went to a near-Earth asteroid, which together with a comet is part of my extended grand tour objectives; I can visit one along the way between Mars and Earth.

    I don't expect any more significant problems. I should be done in 50 years at most.

    Bugs compilation updated

    Spoiler

    A numbered list is so convenient to refer to bugs quickly. This list keeps growing. Problem and Solution

    1) Launching most vessels will crash the game. Must send them to orbit with alt-f12

    2) Ship will randomly get twisted about. Hope it's not too bad, or that it reverts spontaneously. In some cases it is acceptable to alt-f12 in a new vessel to replace the mangled one

    3) Loading the mothership in physical range gets increasingly more difficult, to the point that it crashes the game. Quit and restart the game every time you load the mothership

    4) Propellers start twisting around. No worry, it fixes once you stop time warping

    5) Orbit will get changed upon entering time warp. First warp to 10x, in any case save before warping

    6) Crew transfer function may get stuck. Saving the game often reverts the bug. If all else fails, transfer the kerbal by EVA

    7) Drills won't find ground even though they are on the ground. It goes and passes spontaneously, just accept that mining will take longer

    8) Ship occasionally sinks into ground upon time warping. Just try until it works. Updated: It was limited to Phobos, probably related to microclipping and the extremely low gravity

    9) Pieces get spontaneously detached for no apparent reason. Always check that part count does not change; reload if it does

    10) I can't plan maneuvers or go EVA, the game thinks my buildings are level 1. On starting the game, load the last quicksave instead of going on tracking station. If the bug manifests, restart the game

    11) Chemical plants stop dumping resources they were told to dump. Reset the dump option; doing it once per process is enough for the whole vessel

    12) Occasionally, kerbals will die for lack of power during time warp, even though power is always abundant. Reload when it happens. Updated: save before exiting time warp

    13) Radiation cover glitches during time warp, becoming ineffective even when the sun is completely covered. Set shielding efficiency to 100%, it cancels radiation damage

    14) Docking ports do not undock. This nasty bug must be fixed by editing the save file. KML editor has the function incorporated, I recommend it to anyone with this bug

    15) Actual reliability time is different from what it should be. Just check more often the parts that get broken more often

    16) Intercept on a target disappears randomly. I know the intercept is still there, I can manage with some piloting skill

    17) Crew hatch registers as blocked even though it wasn't, preventing crew from leaving Clamp. Had to move the docking port to free up a different hatch

    18) Some fission reactors are not working, even though they are not broken. Next time I actually break a reactor, I will revert the malfunction with a reload, and drop one of the nonfunctional ones

    19) "Time warp to here" sends me to the next orbit. Always double check on the time, and if necessary time warp manually

    20) Upon starting the game, clicking on the VAB does not work. Clicking on the icon on the bottom left corner of the screen still works

    21) Sometimes elements of the HUD change size. It doesn't affect the game, and seem to revert spontaneously

    22) Sometimes, when the vessel is not in physical range, the nuclear reactors on Cylinder will stop for no reason. Load Cylinder into physical range and they restart

    23) Occasionally, Nitrogenie in a Bottle starts spinning, even though its aerodinamic is balanced. Reload when it happens, and it will get fixed

    24) The ground on Titan and a few other bodies has all sort of glitches and malfunctions. Complex. See 7.3 for more details

    25) Negative aerodinamic drag displayed on the user interface. Drag is still behaving normally, it's only the display that's bugged

    26) The docking port on Clamp has all kinds of problems, does not allow fuel transfer, can't be removed. I stuck another docking port there, and I can grab Clamp with a claw if needed

    27) Sometimes there is no signal for probe control even though there should be. Switch to the vessel that's not being seen, then back to the probe

    28) Crew pod of Hartman rover has a broken life support and a functional wheel, but it instead appears to have a working life support and a broken wheel. Nothing I can do about it; but it still works

    29) The sun shines through Jupiter's body as if it was part of the sky. It's just an harmless visual glitch

    30) An object on the surface coming into physical range may be loaded tens of meters above it. Hope nothing explodes. Reload if necessary

    31) Cylinder's central tanks gets refilled on (useless) oxidizer upon reloading; see 10.2. Dump the dead weight again

    32) All mining drills suddenly manifested a new uranium drilling function. Can't revert it, but they still work normally; it seems harmless

    33) The game is not spawning comets. For the comet landing, pick a large asteroid in an inclined, eccentric orbit and pretend it's a comet

    34) Flags are planted hundreds of meters in the air. Sometimes this crashes the game. Just reload if it happens

    35) Fuel transfer is asymmetrical even when it should be symmetrical. Manually fix to ensure even distribution of fuel

    36) Wheels do not work on Triton. Driving a rover can be skipped

    37) Resources can appear from nothing when exiting time warp. It's benign, and those resources are not enough to make a significant difference     

    38) Sometimes trying to delete a maneuver node crashes the game (old, but wasn't in the list). Reset the offending node to 0 m/s instead of deleting

    39) Strange semicircles of color appear randomly on the screen (NEW). It seems to be a harmless visual glitch

    40) On Triton, an EVA kerbal can explode in midair, ostensibly for hitting the ground (NEW). Alt-f12 the ship in orbit. Go EVA to service the reactors. Alt-f12 the ship back in its place

  6. On 10/22/2022 at 9:02 AM, jimmymcgoochie said:

    The most challenging part of any Grand Tour isn’t designing the vessels or planning the route, it’s putting up with abysmal, slideshow quality frame rates as your thousand-plus-part monstrosity thrashes the single CPU core doing all the work. Docking or doing any kind of EVA work is so much slower and even more painful at 3FPS, plus I’ve found EVAs a lot harder to control properly as they always seem to overcorrect instead of just pointing the way I tell them to.

    of course, one could still run a grand tour with a much smaller and simpler ship. even counting the big landers for the eve-like planets, it should still be within less 300 parts.

    but then, most of the times a grand tour is nothing but a thinly-veiled excuse to go wild on ship design.

  7. 4 hours ago, CaptWhitmire said:

    To clarify Eve Landers I usually make are around the 1.5-meter range usually with 1 Kerbal on board and what I meant by a reasonable timeframe is around a year at minimum. I’ll probably just send over a mining/refueling rover on the surface of Eve for this kind of task if I don’t already have an ISRU on board. 

    eve lander - and by that we assume it's an eve ascent vehicle, since you have a crew and supposedly you want to bring him back - is still extremely vague. an optimized lander can be as light as 50 tons. an optimized lander using propellers to clear the atmosphere can be even lighter. an unoptimized lander can easily reach 500 tons. or it could be an ssto with propellers, vectors and nuclear engines, the most common design i saw is in the 200 tons range.

    since apparently you already have a specific design, and it should work - stock isru is not hard - and it doesn't, you could post pictures of it and we could see what's the problem.

    Is your one kerbal on board an engineer? because if you don't have an engineer, then it's going to take years regardless of anything else you do.

     

    Also,

    assuming you are not extremely good at making eve ascent vehicles and your lander is over 100 tons,

    would it be viable to use a large convert-o-tron? it is a lot more efficient, and it only requires your rocket to be 3% heavier. and you drop it before take off, so it doesn't interfere with ascent anyway.

  8. the 1.5 unit is intrinsecally inefficient, it wastes 90% of the mined ore. for this, i'm not sure fuel cells would work.

    anyway, I'm having troubles understanding your problem. mostly because I have no idea what you would consider a "reasonable time frame" or a "moderately sized lander", and why you can't just add some solar panels if that is your problem.

    There's also the engineer limitation. isru works awfully slowly without an engineer on board, while it works very fast with one. a 1.5 m convert-o-tron properly supplied and with a level 5 engineer can make roughly 1 ton of fuel per day; without an engineer, speed is 1/20th of that. so if your "moderately sized" lander used a jumbo fuel tank (32 tons) and you have no engineer on board, it will take over 1 year and there's nothing to do about it except use an engineer or use the bigger convert-o-tron. Even a level 0 engineer already quintuplicates efficiency compared to no engineer.

    also, if you're relying on solar panels and you're trying to mine eeloo, of course it won't be efficient. I suggest rtgs in that case.

    here's a link to a rover with the small convert-o-tron. it's got 30 tons of fuel, which it can replenish in 30-50 days depending on ore concentration and level of the engineer on board. if you look at it - and ignore all the rover apparatus and focus on the isru part - you will see it's extremely simple; a convert-o-tron, two radiator panels, two small drills. the rover solar panels are enough all the way out to duna.

  9. 43 minutes ago, Beccab said:

     

    Also, are you sure the term is cosine losses? Iirc that one refers to the losses caused by having angled engines, but i can't remember the correct one either

    I've always seen the term used in the forum to refer to inefficiency due to a slow burn where prograde is not aligned with the direction of the burn.

    If it's a mistake, it's a mistake of the whole forum

  10. I read that the orion capsule made an 18 minute burn to a trans lunar injection.

    18 minutes is very long, the ship moves along an 80 degrees angle in that time, making cosine losses rather high. As we know, the efficient way to make long burns is to split them into several apoapsis raising over several orbits.

    Anyone knows why nasa did not try it? Is this some kind of technical concern with the engine that can only be ignited a limited number of times, or what else?

  11. 58 minutes ago, fommil said:

    This is very interesting. I'd like to understand this a bit more. In my return back to Kerbin I noticed that the assist off Kerbin itself (before I came back for the second pass) definitely reduced my Ap and made my next pass be at a much lower relative speed, but maybe there was something else at play there. It's probably, like you say, because I got a different relative speed to the Sun that it gave me a lower energy orbit around the sun but at that particular moment in time I didn't get any advantage relative to Kerbin which is why I only reaped the rewards on the second pass.

     

    actually, this is a trick I myself only learned recently, and the physics behind it is a bit complicated. But it goes like that.

    when you take a gravity assist, you never change your speed relative to the target body. you chain up two consecutive gravity assists with a resonant orbit, second assist you're going to have the same intercept speed you had the first time. On the orbit itself, you lowered both apoapsis and periapsis, which resulted in a less-than-ideal Hohmann intercept, which resulted in having the same intercept speed despite the lower apoapsis. Or maybe you gained some inclination.

    But! now that you are in a new orbit with lower apoapsis and periapsis, you can raise periapsis with a burn in solar orbit. and since your periapsis was only lowered by a small amount, this burn is cheap. and at this point you lowered your periapsis a lot, you have the same periapsis for an ideal hohmann transfer, and you spent less fuel than if you had just lowered apoapsis with rockets.

    so, you cannot change your speed relative to the planet you are using for the assist, but you can set yourself in a trajectory where there is a sequence of burns resulting in a cheaper capture.

    Quote

    Something else I'd like to understand would be how much of  a gravity assist I can reasonably expect off any given body, in dv. Presumably the limit is whatever that body's speed is relative to their parent, but it'd be good to know what some typical values are. e.g. how much can the Mun give depending on how close you get, if it's pointing in the right direction.

    there are two limits. the first is, indeed, speed relative to parent body. if you are moving very slowly compared to your target, you'll end up ejecting very slowly too. so, for example, if you want to go to jool using a gravity assist from duna, you cannot do it by taking a normal hohmann transfer, because you'll arrive to duna with 600 m/s intercept speed, and to reach jool from duna you need 1 km/s ejection speed, so you are too slow compared to duna to reach jool. you need to use a different trajectory resulting in a higher speed relative to duna.

    the second limit is the gravity of the body. predictably, a smaller body gives a smaller gravity assist. for this reason you can gravity capture on jool using tylo or laythe, but you can't do it with vall. and a flyby of bop or pol will leave your orbit almost unchanged. I can't give any hard data on this; by experience, I know that with mun you can gain beteen 50 and 100 m/s, with tylo/laythe you can gain around 500 m/s, with kerbin a bit more. Still, when I wanted to make a duna-kerbin-eve assist, one single kerbin flyby wasn't enough and I had to eject into resonant orbits and make, like, three assists. And I had to use mun in one of them to increase my velocity relative to kerbin, otherwise i didn't have enough speed to reach eve.

    of course i'm talking here of going as close to the surface as you can. if you pass more distant, you get less change. if you could pass underground, you could get a huge deltaV even from a small moon, unfortunately there's that pesky surface along the way.

     

  12. 2 hours ago, fommil said:

    I have always been scared of gravity assists, but when exploring the Jool system I was amazed to discover that I could get a free capture by flying close to Tylo or Laythe. Up until that point I had thought aerobraking was the only way to achieve this kind of thing.

    So on my return journey, which was a 1k dv burn from Laythe back to Kerbin (incredible! especially when compared to the dv chart) I decided to do some playing around with the Kerbin insertion. I noticed that when I approach a body from the left (i.e. as if I were to insert into an inverted, or clockwise, orbit) my craft becomes more aligned with the body I'm flying past, as if I had burnt retrograde. It doesn't seem to matter if I'm jumping up (Kerbin to Jool via Tylo or Laythe) or down (the opposite) an orbit. And conversely, if I approach from the right (i.e. as if I were to insert into a normal, or counterclockwise, orbit) then the body is actually adding to my velocity and the gravity assist looks like I burnt to prograde. Is what I found generalisable or is it just working out this way by accident?

    it's not a matter of left or right, but of passing in front or behind a planet. if you pass behind a planet, you are accelerated, while if you pass in front of a planet you are slowed down. since all the planets rotate in the same direction, it translates to left and right

    Quote

    I managed to time a flyby of both the Mun and Kerbin on my return from Laythe, both pretty close and from the left, which brought me into an orbit with an Ap somewhere between Duna and Dres, which is a pretty big dv saving given that I was coming from Jool! I was impatient and wanted my next Kerbin approach within a year, so I spent about 300dv at that point to get a quick rendezvous but I could imagine waiting some more years and it would have come along naturally. My approach speed after doing this was very very safe for an aerobrake into Kerbin at that point, whereas it would have been touching cloth to have gone straight for the aerobrake first time.

    [...]

    On my return to Kerbin I ended up spending a bunch of dv to get an  intercept on the followup orbit , but is there maybe a trick to get that for free? e.g. maybe trading off some of the saving to get exactly the right orbital period to come back round again for the next pass (within 2 years), I wasn't able to get it to work.

    for a multiple gravity assist, you have to be ejected into an orbit with a duration multiple of the target body - a resonant orbit. that is, if you aim for kerbin and you want to take a second passage, you need to eject into an orbit that lasts exactly 2 years, or 3 years. or 2.5 years, in which case you will meet kerbin 5 years later in a 5:2 resonance. to see how long the new orbit would be, put a maneuver node after the planetary encounter, leave it at 0 m/s; when selecting it, you'll be able to see the orbital time in the lower left corner.

    Quote

    However, it occurred to me that when doing an aerobrake it always has to be from the right (counterclockwise) to go with the surface movement. But that's actually counter-productive compared to the non-aerobrake scenario. Are there any situations where it's worth going into the atmosphere from the left, and staying quite high, to get the benefit of both kinds of decelerations at once? The GA effect from the left is definitely my preference when I can do it, because it is just so much safer than risking the craft on a high speed aerobrake.

    this is a common misconceptions: a gravity assist will not slow you down compared to the planet. it will change your speed relative to the sun, or you can get one from a moon and change speed relative to its planet. but your speed relative to the celestial body providing the assist is always the same. so you still should enter aligned with the planetary rotation.

    Quote

    My only remaining challenge in the game is the Grand Challenge, so I'm thinking of using some techniques to avoid having to mine for fuel along the way.

    Even with gravity assists, a full grand tour requires more deltaV than a ship can reasonably have. so you have a few options if you don't want to mine fuel:

    1) use lots of drop tanks

    2) use ion engines and lots of xenon

    Quote

    are there any good tutorials on gravity assists?

    I'm not aware of any advanced one - the one linked by @Caerfinon is pretty basic and looks like stuff you already know - but, at the cost of looking crass for shipping my own content, I will point out that in my mission reports I do talk extensively of gravity assists with technical details, because I do think a mission report should allow someone else to replicate what you've done.

    So I'll link a few chapters dealing with lots of gravity assists:

    https://forum.kerbalspaceprogram.com/index.php?/topic/203233-lucy-in-the-sky-with-deadly-radiations-3-skys-just-got-a-lot-bigger-kerbalism-opm-grand-tour/&do=findComment&comment=4046683

    this first one is a mission to moho using lots of conjoined gravity assists into resonant orbits to lower deltaV cost.

    https://forum.kerbalspaceprogram.com/index.php?/topic/203233-lucy-in-the-sky-with-deadly-radiations-3-skys-just-got-a-lot-bigger-kerbalism-opm-grand-tour/&do=findComment&comment=4055758

    this is the next chapter, detailing the return trip from moho to the mun using eve

    https://forum.kerbalspaceprogram.com/index.php?/topic/203233-lucy-in-the-sky-with-deadly-radiations-3-skys-just-got-a-lot-bigger-kerbalism-opm-grand-tour/&do=findComment&comment=4068922

    this chapter deals mostly with dwindling life support resources, but subchapter 19.2 uses a jool+tylo gravity assist to reduce speed and set up an encounter with kerbin, and 19.4 details a way to turn that into a low speed encounter with duna a few years later.

    https://forum.kerbalspaceprogram.com/index.php?/topic/208134-lucy-in-the-sky-with-deadly-radiations-4-the-real-sky-this-time/&do=findComment&comment=4139639

    4.2 details going from phobos to venus using an earth flyby, and 4.6 the reverse trip, still using an earth flyby

    https://forum.kerbalspaceprogram.com/index.php?/topic/208134-lucy-in-the-sky-with-deadly-radiations-4-the-real-sky-this-time/&do=findComment&comment=4145720

    this chapter is the trip to mercury, which entails the same amount of gravity assist as the trip to moho i linked earlier

    https://forum.kerbalspaceprogram.com/index.php?/topic/208134-lucy-in-the-sky-with-deadly-radiations-4-the-real-sky-this-time/&do=findComment&comment=4166092

    and this final chapter is my greatest achievement in gravity assists: reaching Io, the innermost moon of jupiter, with limited fuel. It includes 30 gravity assists.

     

    I do believe you can find more informations there than in most guides.

     

  13. Part 13: Deep Blue Dot

    Cylinder goes to a Neptune flyby, drops Clamp on Triton, returns to Uranus for refueling.

    Two more nuclear reactors are broken, putting strain on the long term energy supply of the mission.

    WP4CkmI.png

    Triton with Neptune in background

    13.1) How the heck do I eject from this place???

    Spoiler

    I barely have time to lift off from Titania before one of the wolfhounds on Trypophobia goes kaboom!

    rXG9UX1.png

    Trypophobia, now with four wolfhounds active

    I already used up the one spare wolfhound I did carry, but Trypophobia can still work with 4 wolfhounds if I shut down its opposite for symmetry.

    Now I have to split up A'Twin. Neptune only has one moon - Triton - rendered in this mod, and for some weird reason Triton only has 3 biomes; north pole, south pole, and "flatlands" covering everything else. And none of those 3 biomes had water.

    While transfering fuel from the various tanks - I want to remove all oxidizer from Cylinder, and leave Trypophobia with the proper amount of liquid fuel - I noticed another issue. I select all fuel tanks and tell them to drain into a central one to maintain a symmetrical balance of fuel, but despite that fuel is being moved faster from some tanks. Despite those tanks being perfectly identical. Oh, well. List updated with Bug #35.

    wrqbWcU.png

    Bug #35: all fuel tanks started equal, and they were told to drain simultaneously; still one tank is a lot more full than the others

    To minimize the impact on the center of mass, I have to fix things up manually. I barely went to Titania's orbit, and I already have a critical malfunction and a new bug; what more could possibly go wrong?

    Next is splitting up the ship

    fT2LuXo.png

    Once more, A'Twin is separated into its two modules

    1wKibpI.png

    And here we have old bug #9 manifesting. Good thing I'm keeping track of part count

    I carry to Neptune Clamp and Fat Man, but I do leave behind the additional tank of Fat Man because I won't need it.

    x6T7FB9.png

    Cylinder, ready to go. Even though I need many high energy transfers, 10 km/s should really suffice

    IUnBLoU.png

    Trypophobia, staying behind. I left it with baely enough fuel to land again

    Wow, it feels so weird to have the game displaying accurate deltaV figures for both pieces of my mothership!

    Now I've got to find an efficient way to leave Uranus. The moons being rotated by 90 degrees makes leaving very difficult. I am using the movement of Titania around its orbit as part of the maneuver, something equivalet to a normal burn, while I had to include strong normal and radial components to exit in the direction I wanted - which was not aligned with the plane of the moons at all.

    dVIEWkn.png

    Maneuver to leave Titania for a Neptune intercept

    iuKan3Y.png

    Same maneuver, zoomed out

    0bgYLrc.png

    Same maneuver, zoomed in, I am basically stopping my orbit and going in a completely different direction

    Neptune is too close to Uranus for a proper Hohmann, but such a trajectory would have been too slow in any case. A close Neptune suits my needs. I could have spent more fuel for faster transfer, my choice was a compromise between saving time and saving fuel.

    0sB8epA.png

    Leaving Titania, Cylinder broke another engine

    That one is my fault, I got distracted and didn't perform the engine checkup when remaining burn time went below 30 minutes. As a result, when it became lower than 25 minutes an engine broke.

    I'm out of spare engines, but the ship had 24; I shut down its symmetrical - which I can now use as another spare - and I only lost 8% of maximum thrust.

    13.2) Free return trajectory is not for free

    Spoiler

    I want to try something new: a free return trajectory. In theory, I could use a gravity assist from Neptune to return to Uranus. Since I only have to visit one moon, I can drop Fat Man and have it catch Cylinder back. I could not plan for this before leaving Uranus because you can't set a planet as target while you're orbiting it.

    Turns out, I could use a free return trajectory - if Neptune was a black hole of equivalent mass.

    SrvPTMe.png

    The free return trajectory would require a huge change at Neptune, which would require passing below the surface

    nmfxu1l.png

    The best I can get: I use a gravity assist, but I've still got to pay 2500 m/s to exit Neptune in the proper direction

    After some simulations, I went for it. This not-so-free return sends me on an Uranus intercept - and a cheap one at that - for 2500 m/s. Getting captured around Triton, on the other hand, would cost 2600 m/s; more, after cosine losses are factored in (notice: Triton has a thin atmosphere, but it's not enough for aerocapture; I tested it). And then returning from Triton to Uranus would cost more than 2 km/s. So I'm still saving a lot of fuel.

    TiUZcX0.png

    Full trajectory from leaving Uranus to returning

    xAi8OLy.png

    Side view to gauge my chances at Pluto later

    Once more, I could go fastr by spending more fuel, and Cylinder will have 5 km/s left. But there's no need to hurry; the best time to launch for Pluto is close to the planar node, and - considering that Uranus orbit is 84 years - the current trajectory would return 15 to 20 years before that time; factor in 10 years for refueling, I'll still have to wait a bit.

    Now I have to pass 15 years, doing periodic maintenance trips for the fusion reactors - the only parts of the ship that are still aging.

    zWmvwhy.png

    Trypophobia lands back on Titania

    3pBvaJU.png

    Trypophobia breaks a nuclear reactor

    Case in point. Seven reactors left out of 12. Because of bug #18, I reverted this malfunction and dropped one of the nonfunctional reactors instead. Then I went on a few more years. Then I had to move to Cylinder because, due to bug #11, I can't run water electrolysis remotely. Then I reloaded Trypophobia, as I need to service the reactors every year. As soon as loaded, the ship broke apart. Loading previous saves also broke the ship. It turns out the save file had clipped the discarded reactor inside the ship, causing the two to collide as soon as they were loaded. Fortunately I was able to delete the offending debris manually by editing the save file, so I didn't have to reload many years of gameplay. And it wasn't even technically a bug.

    13.3) On Neptune

    Spoiler

    200 days from Neptune, I detach Fat Man with Clamp to set it for a Triton intercept. I also accelerated it a little bit to make sure there would be no overlapping of the Triton capture burn with the Neptune periapsis burn of Cylinder. I could have waited more, but the burn would have been more expensive, and I still wasn't sure how much I would need to return to Cylinder afterwards.

    ebZayoX.png

    Fat Man departing from Cylinder

    I68wD8o.png

    And finding a trajectory for Triton

    Triton orbits retrograde from any other moon, but when it's the only moon modeled by this mod, it doesn't really make any difference. Intercept speed is high because I'm coming from a high energy trajectory, but Fat Man has lots of deltaV.

    90f3qqe.png

    Neptune and Triton. I like the dark blue hue

    i2rP1bn.png

    More Neptune and Triton

    CzoDYfh.png

    An attempt at aerocapture, hopefully tried because Fat Man is so draggy. Even a few km above the ground, pressure is very low, drag is tiny. DeltaV gained is 30 m/s

    RWYCDTG.png

    So I had to suck it up and use the rockets all the way

    6sHnvJX.png

    Triton's surface

    CorvKb9.png

    Clamp about to land. Or to crash down, because I'm still delaying engine use in the hope of getting some measure of aerobraking

    But bug 17 is still active, and the crew can't leave to plant a flag or collect a sample. So I had to reload and land with a kerbal on the ladder.  I was worried about the atmosphere, though. Why would I be? Have I not yet understood that Triton's atmosphere is just for show? Even close to the ground, Adai could let go of the ladder and fly around with the jetpack, the air only providing the barest modicum of resistance.

    T2TKYuk.png

    Flag planted. I really do like the lighting on the surface, though Enceladus was better

    DTRPAA3.png

    The same scene, in natural light. I still make a point to check how things would look without light amplification from time to time

    As I liked Triton's surface, I tried to drive around. But after a few meters, the wheels suddenly lost grip. They were spinning, but the rover was immobile. Bug #36. I already met this bug in my previous OPM grand tour, seems related. Triton's surface also has some weird behaviour similar to Titan's - you can see the wheels sinking into the ground - so I updated bug #24. I wonder if a rover on Titan would similarly fail to function.

    I took a picture of the bug to show, but the wheels spinning doesn't show in the still image, so there's no point. Anyway, I just gave up on trying to drive on Triton and resolving to GTFO as soon as possible from this bug-riddled place.

    ZMTBh9I.png

    Meanwhile, Cylinder makes its first burn at Neptune periapsis

    Now Fat Man has to catch Cylinder. First thing, it has to wait a few days because Triton is in the wrong part of the orbit. Then, since the game will never give me a close approach between two ships in escape trajectories, I set up some maneuver nodes at intervals for Cylinder to have a marker for where it would be at a certain time. Then I made similar markers for Fat Man. Then I tried to make a maneuver that would overlap two such markers.

    Fat Man has 6 km/s, and 2 km/s would suffice for a return trajectory to Uranus, so I am not worried about fuel availability.

    WQ6XvRJ.png

    Finding an intercept with Cylinder. the two maneuver nodes are both in roughly 19 days, showing that the two ships will be close after that time

    tpP4vlp.png

    Here I refined the trajectory, the two nodes are perfectly overlapping

    Of course, "perfectly overlapping" is purely visual here, and it will still mean tens of thousands of kilometers at close approach. But it something I can work with. Once I am close enough to Cylinder, I can start to burn to ensure that my prograde marker stays firmly over the target marker.

    T6SrlfV.png

    Burning to push the prograde marker over the target marker. Actually it's the retrograde marker over the anti-target, but it's the same principle

    vWltNSm.png

    Reunited with Cylinder

    Those 200 days spent in Fat Man brought the crew to 30% stress, but the only outcome of this was a nervous breakdown resulting in a reversible damage.

    13.4) Return to Titania, now with 50% more plane change

    Spoiler

    Now it's 22 more years of doing nothing but waiting, going EVA to fix the reactors, make more ammonia, wait, fix reactors, make ammonia, wait, make nitrogen, make oxygen, make CO2, wait, wait, wait. Why do I even play those kind of missions?

    sxCu1b0.png

    Year 216: another nuclear reactor fails

    Now I'm down to 6. I can lose another couple before it really starts to hurt. How many reactors will be left once I reach Pluto? Only time will tell.

    56yPp4N.png

    A nice picture taken while performing maintenance. But do notice the empty holes where engines and reactors used to be

    No more accidents in the next 20 years, now I have to plan for Uranus insertion (no puns, please).

    Which is going to be even more annoying than the previous time, because the moons plane is rotated even worse and I can't get any better than 60 degrees inclination. Why did I ever landed on Uranus in the first place? Iapetus was such a nice place for refueling, and whatever extra fuel I'd have to spend to go from Saturn to Uranus orbit is more than compensated by not having to deal with this inclination and being able to aerobrake at Titan.

    Oh, because using Uranus this way takes less time and gives me a chance to be ready to launch for Pluto in a transfer window. Damnit!

    Anyway, fixing that much inclination is going to cost a fortune, and there's no way around it. Spending a fortune is the best solution, the alternative being spending more fuel than I've got.

    E7VEHne.png

    Trajectory to reach Titania

    My approach is thus: first, 200 m/s close to Uranus to get captured in an elliptic orbit. I could have saved some fuel by being captured in an even higher orbit, but I don't want to waste too much time either. Then 580 m/s at apoapsis to get a high orbit. This orbit is high enough that I can make a 60 degrees plane change for "only" 1762 m/s. It also lowers periapsis t touch Titania's orbit. At this point there's a small correction burn of 12 m/s, and finally a 450 m/s capture burn on Titania.

    All in all I'm spending almost 3 km/s for this. But it's well within Cylinder's capabilities.

    0lTNOEM.png

    Uranus periapsis

    5IhrVvs.png

    Rendez-vous with Trypophobia

    jkjUitv.png

    Moving the shuttles around to prepare for joining the twins. Fat Man additional tank has no engines, so I'm docking it in this peculiar way

    pDQKAYO.png

    Also featured using Fat Man's engines as an impromptu RCS

    TKb72ra.png

    Cylinder and Trypophobia docking, seen from inside a nearby Spider. A view I was still missing

    QFWn2cn.png

    Descent on Titania

    J3ezQox.png

    Landing with only nuclear engines. Not for precision, but because I've been careless and run out of oxidizer too early

    Landed back on Titania in year 237, 38 years after departing. Now I am looking to roughly a decade of refueling.

    By the way, another bug (#37): this time I set up to use all my CO2, so that there is none in storage. But as soon as I stop time warp, some CO2 and ore appear. This is another benign bug, gifting me stuff. And unlike bug #31, this one gives me some actually useful resources, and not some dead weight I must remember to dump every time (btw, I forgot it in the whole Titania approach phase). But the amount of resources is too small to make any meaningful difference, especially since I only stop time warp a couple times per year (once for reactor maintenance, once to make new ammonia).

    l1bdyS0.png

    Reaction wheel broken on Nitrogenie in a Bottle

    That reaction wheel was one of the few pieces still aging; I was leaving it reversibly broken so I wouldn't have to worry about it, but I had to fix it to dock Nitrogenie, else it was completely out of control. Then I ignored it; just not worth the effort. I was hoping it would get reversibly broken again, but I still have a bunch of spare reaction wheel in case I ever need to stop at Titan and make new nitrogen.

    LT9OFpe.png

    Crawling through tunnels - or, well, flying up narrow vertical ducts - during maintenance

    fPiBe5x.png

    Status after 11 years of refueling

    JZW7Iav.png

    Position of Uranus and the planar node with Pluto

    Pluto could be very tricky. It's very small, so I won't get any Oberth effect for capture; we're easily talking several km/s intercept speed. Add several km/s of ejection burn, especially with the crappy alignment of Uranus moons, and it will be expensive, but still feasible. However, Pluto itself is fairly large, requiring roughly 1 km/s to land on - hence why I'm carrying lots of oxidizer. But wait, can't I just land on smaller Charon instead? No, because Charon has no water anywhere (insert more ranting against the mod). A'Twin as whole has roughly 8 km/s, and it's got to spend 600 m/s just to each Titania's orbit; I should still have enough, especially factoring in the very long life support.

    Oh, and just to be even more annoying Charon has uranium, which is lacking on Pluto; so I have to carry all the uranium, land on Pluto, make fuel with the uranium I have - I'll go somewhere above half tanks - then take off, land on Charon, fill up on uranium again, land on Pluto, finish refueling, leave.

    But no point worrying before starting a simulation. A'Twin is as prepared as it could possibly be for this trip. I've got all the resources I can keep, I can spend 60 years in space. I even have a ship much lighter than it was at start, thanks to dropping well over 100 tons of broken hardware. I reached Mercury, I conquered Io, I managed a landing on Mimas, I don't expect Pluto to be any worse.

    Electricity may be a problem in the future. I will surely have enough reactors to keep going at Pluto, but afterwards I'll probably need an additional stop on the way back, I doubt a direct Pluto-Earth trajectory will be feasible. I'll have to stop either at Iaptus or at Phobos, and I worry in what state my reactors will be by then.

    Bugs compilation updated

    Spoiler

    A numbered list is so convenient to refer to bugs quickly. This list keeps growing. Problem and Solution

    1) Launching most vessels will crash the game. Must send them to orbit with alt-f12

    2) Ship will randomly get twisted about. Hope it's not too bad, or that it reverts spontaneously. In some cases it is acceptable to alt-f12 in a new vessel to replace the mangled one

    3) Loading the mothership in physical range gets increasingly more difficult, to the point that it crashes the game. Quit and restart the game every time you load the mothership

    4) Propellers start twisting around. No worry, it fixes once you stop time warping

    5) Orbit will get changed upon entering time warp. First warp to 10x, in any case save before warping

    6) Crew transfer function may get stuck. Saving the game often reverts the bug. If all else fails, transfer the kerbal by EVA

    7) Drills won't find ground even though they are on the ground. It goes and passes spontaneously, just accept that mining will take longer

    8) Ship occasionally sinks into ground upon time warping. Just try until it works. Updated: It was limited to Phobos, probably related to microclipping and the extremely low gravity

    9) Pieces get spontaneously detached for no apparent reason. Always check that part count does not change; reload if it does

    10) I can't plan maneuvers or go EVA, the game thinks my buildings are level 1. On starting the game, load the last quicksave instead of going on tracking station. If the bug manifests, restart the game

    11) Chemical plants stop dumping resources they were told to dump. Reset the dump option; doing it once per process is enough for the whole vessel

    12) Occasionally, kerbals will die for lack of power during time warp, even though power is always abundant. Reload when it happens. Updated: save before exiting time warp

    13) Radiation cover glitches during time warp, becoming ineffective even when the sun is completely covered. Set shielding efficiency to 100%, it cancels radiation damage

    14) Docking ports do not undock. This nasty bug must be fixed by editing the save file. KML editor has the function incorporated, I recommend it to anyone with this bug

    15) Actual reliability time is different from what it should be. Just check more often the parts that get broken more often

    16) Intercept on a target disappears randomly. I know the intercept is still there, I can manage with some piloting skill

    17) Crew hatch registers as blocked even though it wasn't, preventing crew from leaving Clamp. Had to move the docking port to free up a different hatch

    18) Some fission reactors are not working, even though they are not broken. Next time I actually break a reactor, I will revert the malfunction with a reload, and drop one of the nonfunctional ones

    19) "Time warp to here" sends me to the next orbit. Always double check on the time, and if necessary time warp manually

    20) Upon starting the game, clicking on the VAB does not work. Clicking on the icon on the bottom left corner of the screen still works

    21) Sometimes elements of the HUD change size. It doesn't affect the game, and seem to revert spontaneously

    22) Sometimes, when the vessel is not in physical range, the nuclear reactors on Cylinder will stop for no reason. Load Cylinder into physical range and they restart

    23) Occasionally, Nitrogenie in a Bottle starts spinning, even though its aerodinamic is balanced. Reload when it happens, and it will get fixed

    24) The ground on Titan (UPDATED: and a few other planets) has all sort of glitches and malfunctions. Complex. See 7.3 for more details

    25) Negative aerodinamic drag displayed on the user interface. Drag is still behaving normally, it's only the display that's bugged

    26) The docking port on Clamp has all kinds of problems, does not allow fuel transfer, can't be removed. I stuck another docking port there, and I can grab Clamp with a claw if needed

    27) Sometimes there is no signal for probe control even though there should be. Switch to the vessel that's not being seen, then back to the probe

    28) Crew pod of Hartman rover has a broken life support and a functional wheel, but it instead appears to have a working life support and a broken wheel. Nothing I can do about it; but it still works

    29) The sun shines through Jupiter's body as if it was part of the sky. It's just an harmless visual glitch

    30) An object on the surface coming into physical range may be loaded tens of meters above it. Hope nothing explodes. Reload if necessary

    31) Cylinder's central tanks gets refilled on (useless) oxidizer upon reloading; see 10.2. Dump the dead weight again

    32) All mining drills suddenly manifested a new uranium drilling function. Can't revert it, but they still work normally; it seems harmless

    33) The game is not spawning comets. For the comet landing, pick a large asteroid in an inclined, eccentric orbit and pretend it's a comet

    34) Flags are planted hundreds of meters in the air. Sometimes this crashes the game. Just reload if it happens

    35) Fuel transfer is asymmetrical even when it should be symmetrical (NEW). Manually fix to ensure even distribution of fuel

    36) Wheels do not work on Triton (NEW). Driving a rover can be skipped

    37) Resources can appear from nothing when exiting time warp (old, but wasn't in the list). It's benign, and those resources are not enough to make a significant difference     

    Broken parts compilation

    Spoiler

    I want to keep track of how much stuff I break, and how much it's affecting the mission, so I prepared a list

    Life support

    1 life support broken on Dolphin 1. I've got five more redundant pieces on it.

    1 life support broken on Dolphin 2. I've got five more redundant pieces on it.

    1 life support broken on Cylinder. It's a redundant piece of a redundant piece. Least concern.

    1 and only life support broken on Hartman. Sucks, I can't take extended trips, but the rover has enough air to conduct landing operations safely.

    1 life support broken on Fat Man. I've got five more redundant pieces on it.

    1 and only life support broken on Nitrogenie in a Bottle. No problem, it's not supposed to carry a crew any longer.

    Nuclear power

    6 Excalibur reactors broken. Up to 4 can be lost before mining is slowed down - though it is already slowed by bug #18. There is concern here that they are breaking up fast. (+2 NEW)

    Reaction wheels

    2 large reaction wheels broken. I've still got 88 working.

    1 medium reaction wheel broken on Clamp. I've got a half dozen spare ones in storage.

    2 medium reaction wheel broken on Nitrogenie in a Bottle. I've still got a half dozen spare ones in storage. (+1 NEW)

    reaction wheel on the crew pod broken on Nitrogenie in a Bottle. Can't be replaced, but the other three wheels should be enough to keep the plane stable even if I break a lateral engine.

    Engines

    4 big nervs broken. I had three spare ones. Now the ship is working with 22 engines out of the original 24. (+1 NEW)

    2 big wolfhound broken. I had a spare. Now the ship is working with 4 engines out of the original 6. (+1 NEW)

    1 small nerv broken on Fat Man. I've got 2 more spares, then I can start cannibalizing Nitrogenie in a Bottle.

    1 cheetah broken on Spider. I've got 2 more spares.

    Communication

    1 RA-100 dish broken. I've got 5 more redundant pieces. After that, I still have more non-relay antennas.

    1 HG-5 antenna broken on Wings B. I've got 1 more spare. After that, the mission can still use normal non-relay antennas.

    1 Communotron 88-88 antenna broken on Fat Man. It was itself a spare part, and I have more spares, as well as redundant antennas.

    1 Communotron 88-88 antenna broken on Wings A. I've got a few more spares; then I can cannibalize antennas from Trypophobia if really needed.

    Others

    1 radiator panel broken. I had 12 redundant. They should be needed to vent heat from the nuclear reactors, but they are not actually needed anyway.

    Drills

    Drills never got broken, even though I stopped checking them 200 years ago. Bug #15 working in my favor.

    Chemical plants

    Chemical plants  never got broken, even though I stopped checking them 200 years ago. Bug #15 working in my favor.

    Low-quality parts

    A landing light broken on Nitrogenie in a Bottle. Irrelevant, I don't need them.

    Life support on Trypophobia's gravity ring broken. Irrelevant, it only does pressure control and the same function is included in the greenhouses.

    1 Converter broken. Irrelevant, converter is the stock isru functionality that I'm not using. I need the chemical plant functionality, and that one is still working perfectly.

    Outdated

    2 reaction wheels broken on Milly. Now Milly has done its job.

    1 dart engine broken on the Mars Descent Stage. Now it's a pile of debris on Mars.

    Discounting the low quality and outdated parts, that's 31 critical malfunctions so far.

  14. Just noticed this report, I'll be following it. Not many people use my style of (detailed) reports. And I'm definitely thinking of trying this pack as soon as I finish my current grand tour.

     

    However, if I can give one piece of advice, you should put the reports under spoilers. It makes the page a lot easier to navigate.

  15. you need to pass in front of mun, not behind it.

    it's basic gravity assist theory: if you pass behind a planet, it will accelerate you, while if you pass in front of it, it will slow you down.

    as for maneuver nodes not showing much in the future, indeed after a few changes of SoI the game stops showing trajectories. the workaround for that is to set up another maneuver node - keep it at 0 m/s, you don't want to actually make a maneuver there - forward into the future. in this case, you could make it in munar orbit. this will persuade the game to show you your planned trajectory a bit longer

  16. On 11/8/2022 at 10:50 AM, magnemoe said:

    Make me thinking if doing the braking burn in low Jool orbit might make sense? its easy to set up and the high velocity should give you lot out of your fuel, note that you will then need an Tylo flyby to raise Pe and lower Ap. I wonder if this save more fuel than an tylo braking burn? 
     

    braking in low jool orbit is normally a bad idea; not much because of the cost, as you remarked it is very cheap because Oberth (iirc 200 m/s to get captured arriving from kerbin), but because when you go to jool you always move to a moon afterwards, and to go to a moon a low jool insertion is bad. as you know, the more similar your orbit is to that of your target, the lower the intercept deltaV is going to be; and if you have a periapsis skimming jool's atmosphere, that's going to result into an expensive transfer to whatever moon you're aiming at.

    this is the second reason you're better off using a gravity capture at tylo or laythe; not only you save the insertion deltaV entirely, you also end up in an orbit with a lower insertion deltaV for the moons.

    I say it's "normally" a bad idea because there are corner cases where you want to do this: namely, when you come to jool with such a high intercept speed that using gravity capture is impossible, and what you gain by oberth effect far offsets the extra cost of injecting into a moon. not something that happens very often, but if for some reason you're using a high energy trajectory, then this is more efficient.

    another case where this option is best is for gas giants other than jool; On jool you have two big moons perfect for gravity capture, but there are lots of modded planets out there lacking such luxury.

    In the OPM system, it can be a good strategy to inject into urlum - though direct injection at wal is often preferrable. For Sarnus and Neidon, aerobraking at tekto and nissee respectively are generally the best options, but injection into low orbit of the gas giant is the next best thing if aerobraking is not possible.

    In RSS, direct injection into low orbit is the best method of capture for uranus and neptune, because none of their moons are big enough for gravity capture or direct injection. with jupiter direct injection into a moon is often convenient, depending on the mission. as for Saturn, if you're performing a grand tour or similar mission and you're not coming from earth, you generally can aerobrake on titan; but if that's not possible, again, injecting into low orbit is often for the best.

    so, injection into low orbit on a gas giant is actually the most efficient way to get captured in many cases; however, jool is just so conveniently set to give better options that you don't want to do it there. other modded planets, including the real planets we have in our solar systems, don't have such conveniences and justify that injection strategy

  17. to keep the mission within reasonable mass, you can use an helicopterocket. it's still going to require several tens of tons, though.

    sAZnsC7.png

    an example of helicopterocket. at 15 km of altitude it jettisons the helicopter part and goes up like a rocket

    as for reentry, landing on eve tends to require some careful sequence. here i am first dropping the upper heat shields - which I use as aerobrakes and to keep the craft pointed the right way

    h0lNNTI.png

    Ns081LL.png

    that's because they fall slower than the rocket, so they have time to move away

    then I activate the parachutes

    y0Et6v1.png

    including parabrakes first, because opening the main parachutes too suddenly may destroy it.

    finally, now that the rocket is falling slower than the thermal shield would on its own, I can drop the lower thermal shield. parachutes are opened at high altitude to give more time to gain distance from the shield.

    xiz9oN6.png

  18. 3 hours ago, Richmountain112 said:

    Now I know to stack more heat shields when going to the Outer Planets. Does that even work?

    it works partially.

    but really, you don't need to stack heat shields. a properly made reentry pod still works. i reentered safely at up to 9 km/s with nothing but a pod and a thermal shield.

  19. alternatively, you could aim for duna and aerobrake there; duna is a lot more forgiving on aerobraking due to its lower gravity, so you may be able to survive. of course, then you need to go from duna to kerbin. fairly cheap if you have some fuel left, but not feasible if you discarded all the ship to keep only the reentry pod.

    Aiming for eve and using its gravity assist to go to kerbin at a lower speed is also possible

  20. 2 hours ago, miklkit said:

    Yeah there is a bug somewhere.  The plane had been flown to Ike, then Dres by MJ and it was only when going from Dres to Kerbin that it changed targets to Jool, so there should not have been any old things to trigger it.  I'm going to reinstall MJ and if this still happens, then the whole game will be reinstalled. 

    or, you could learn to perform those maneuvers manually. it will be hard at first, but you can be a lot more efficient than mechjeb is, and it will be a lot more fulfilling.

    besides advertising my own agenda on how this game should be played, I can attest that this game has a mod to fix everything, but the more mods, the more it becomes instable. all those mods add their own issues. In the end I found that it's better to not rely on a mod unless you really have to.

    Wait, does that still count as advertising my own agenda on how this game should be played? Damnit!

  21. Part 7: A premature end

    The Jool mission arrived to Jool. It got captured in orbit. However, it was seriously lacking in xenon. I don't have enough to return to Kerbin. Not on a high energy trajectory, at least.

    If this was one of my main challenges, I'd go back to the drawing board and fix the problem. Just adding 4-5 extra xenon tanks would suffice. Except that would require replaying every other mission too. Lots and lots of slow xenon burns.

    I lost the passion in this challenge long ago. I picked it up thinking it would take a few weeks. Now I don't have a problem I can immediately fix, and I don't have the dedication to reload all the way back. The worst part is, it wouldn't even be interesting. There is no engineering to be done, no playing with orbits. All I'd have to do is add a bunch more xenon, and then do exactly what I've already done. I've already shown completing a return mission from anywhere in 2 years is possible, I'd only need to follow through.

    So, I'm giving it up.

  22. Finding myself with a bit of a problem here. I am about to split my mothership in two, and I am transferring the fuel to the part that will need it most; routine operation, but I noticed something different

    If you can't tell from the image, there are a bunch of fuel tanks with a radial symmetry. I selected all of them simultaneously, then drained the fuel to another target tank

    pMcZpKj.png

    Here I noticed that some of the fuel tanks had a lot more fuel left than some others.

    the tanks are all symmetric. they are all identical. I started with my tanks full after completing isru on the planet below, and they were all at the same level after ascent.

    yet now that I drained them into the big tank, their individual fuel levels changed. some tanks were drained faster than others.

    as you can imagine, this is going to be a problem because my fuel mass will no longer by symmetrical. it may lead to asymmetric thrust and the ship spinning - though as long as the difference is small, the reaction wheels and gimbals can compensate.

    I want to stress once more than I never did anything that could differentiate those fuel tanks. I selected them all simultaneously before giving the transfer order - which was for the larger tank to get fuel inside it.

    Anyone knows why fuel is behaving like that, and how I can fix the issue without manually readjusting all the tanks?

     

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