herbal space program

Oops! I read 5912 instead of 5219. And I'm sorry to hear the second flip isn't so easy. I was able to get captured without aerobraking from my final prograde orbit, so I figured it wouldn't be so hard with the small additional relative velocity going retrograde. My plan was basically to do part or all of the resonant ladder I took down to Burbarry backwards and then get captured from that highly eccentric reverse orbit, but I guess we'll see...

So just to let everybody know I'm still at it, I've so far managed to get to a reverse orbit with AP between Duna and Kerbin and PE around Moho's aphelion, for a total of 1638m/s from my initial LKO. My album so far, very much still a work in progress, is here: I'm using a SSTO space plane that makes orbit with right around 5.9km/s dV, so it's beat @jonny's record or bust! I've dropped the idea of using plane changes, instead using several Jool encounters to incrementally reverse direction. So far I've used 15 gravity assists to get here, consisting of Mun, Kerbin twice prograde, Jool four times, Eve eight times retrograde, and then Kerbin three more times retrograde. So far, other than many small corrections to dial in the next encounter, I've only had to burn four times to change my orbit significantly, comprising three DSMs of 207, 81, and 37m/s to set up my first Jool encounter, and also one 10m/s retrograde burn to find a Kerbin encounter in the gulf between 4:3 and 2:3 resonanace. The rest of it was just about setting up the next encounter to raise or lower my orbit between different resonant energy levels. From here however it will get more complicated, as I don't really want to lower my orbital energy beyond where it is now. I'll therefore probably keep boosting prograde after each successive Kerbin encounter to stay at 3:2 (for about 100m/s per encounter), to keep raising my PE and lowering my AP with Kerbin's help. I estimate I could get to Burbarry for about 2300m/s by brute force from here, but I'm hoping I can cut that in half or better by doing several more gravity assists at 3:2. My gut feeling is that getting home won't be nearly as difficult, as I suspect I can probably get captured by Jool if I can hit it from a sufficiently eccentric reverse orbit, which should allow me to get home for a few hundred m/s from there using Tylo-Kerbin 2:1 - Kerbin3:2 - re-entry. Anyway, we'll see about that. I still obviously have a long way to go, but I'm optimistic I can pull this off for less than 5.9km/s....

Just re-quoting this by way of announcing that after quite a few hours I'm finally giving up on this approach. Starting from an orbit that went outside of Jool and well inside of Moho, I was able to use Eve to get to around 50 degrees inclination before the speed became so high that I was getting only a couple of degrees per pass on a 3:1 resonant orbit. I could have kept at it, dropping to lower and lower orbits, but timing the encounters properly was getting to be a real hassle already. I suppose that using Jool to do this would be significantly easier, due to the higher gravity and much lower relative velocities, but it would take just forever in game time to do it from a higher-energy orbit than Jool's. I think I'm going to back my game up to after my second Jool encounter and try again from there. So far, I've started by raising myself to a Kerbin PE outside-of-Jool AP orbit that encounters Jool inbound using only Kerbin assists and DSMs, for right around 1400m/s from LKO. From there, I ejected outwards and backwards to get an orbit that went further outside of Jool's and dropped to a PE inside of Eve's, which re-encountered after about 1.3 orbits. From this encounter, it got to an orbit that went quite close to the sun and had its AP near Jool, from which I started using outbound Eve encounters to try to flip the pancake. This time, I think I'll use my first Eve encounter to fling myself out to a 30 year or so orbit, then narrow than even further at AP and try to hit Jool inbound again. I'm pretty sure that will be enough to turn me around, but it won't be quick. Anyway, I'll post an album once I'm confident I've got a plan to at least get there...

True, but Eve has got a whole lot of gravity and a pretty short period, so I think it might not be so bad. We'll see..... Well plan A didn't work. I launched into a polar orbit and swung around Eve from there to get to an orbit that was the same size as Eve's but 8 degrees tilted, and that was as far as I could get. Subsequent encounters could not change my inclination any further as I had thought they might, because in that situation your motion inside of Eve's SOI is already completely normal. The only way to change that would be to push AP in or out from there to create some prograde or retrograde relative motion going into the next encounter, which can then be converted to normal motion. I'm not giving up on finding a way to "flip the pancake" quite yet, but it looks to me like it will require some sort of back-and-forth between Jool, Eve, and Kerbin. I guess my next plan will be to see how much plane change I can get if I first fling myself to the highest resonant orbit I can off of Eve and then turn all that relative motion normal. Plan C I guess will be following the 3:2-2:1 ladder to Jool I worked out a while back: Album a/XQSnn will appear when post is submitted and seeing what I can do from there. That method can get you out to Jool for around 1300m/s every time Kerbin is ~33 degrees ahead of Jool, which is a bit more expensive but much more frequent that the PLAD KEKKJ route. I'm sure I can gin something up using that. My rescue plane makes LKO with almost 6km/s, so I still have hope that I can pull this off with a single stage. Stay tuned...

I was in the middle of building a giant space station for Jool 5 to land on and return from every body, but this sounds too fun to pass up! I think I'm going to try it with a space plane, maybe taking a shot at the dV record. It looks like what everybody has done wrt gravity assists so far is to go for a direct reversal of trajectory at Jool. It seems to me that another strategy that might work is to set up a 2:1 resonant orbit with Eve and use repeated encounters on that orbit to incrementally tilt my inclination towards Kerbol polar and then ultimately retrograde. I'm not sure what the energetics of this will look like, so I may have to use a ladder of resonant orbits, but I don't see any immediate reason why this shouldn't be doable in both directions. If it works the way I hope it will, I should be able to get it done for not too much dV and quite a bit less then 100 years. But of course the devil is in the details....

So this is where the party is. Rolling up sleeves....

Absolutely. Those heat shields reduce terminal velocity down low from something like 200m/s to something like 38m/s. Without them, it would be pretty hard to slow down quickly enough with just the rotor blades. However, once I've slowed down, the blades alone are enough to hover near the ground. I was even able to do it with fewer, but the more blades you have, the slower you can spin, and consequently the easier it is to land. As I said in my album post, the original ship had landing gears on hardpoints arranged in a circle around the base, but I accidentally ejected those in orbit. I'll probably try again a couple of times tonight to see if I can "stick the landing" and come to a rest upright on the wheels, perhaps even on the runway/pad!

I actually already did it! I don't have time to fully annotate it now, but my ship weighs around 9000kg on touchdown, and I have a screenshot showing a velocity of 0.4m/s just above the ground. I'm pretty sure that set-up will work on Duna and Laythe as well, Eve not so much. Anyway, I'll add captions and more commentary this evening......

I'm fairly close to having it working already. Not quite there yet, but I'm pretty confident....

Oops! Sorry. I was in a rush, looking at this forum when I should have been working. Anyway, the way @DesertEaglehas written the rules, any glider that can land from orbit in one piece will get an infinite score, regardless of mass or velocity. I guess the way to fix this and convey the OP's actual intent would be to make the parachute denominator term 1+ the number of chutes instead of 1.5X the number, so we can't trivialize the challenge using division by zero. In any case, assuming that correction is made, I'd say that the ultimate winner of this challenge will be a copter of some kind. You could drop it from some powered ship with a big fat heat shield underneath it, then spin it up as you near the ground. Based on my prior experience with copters, it would be easy to get a screenshot just before touchdown with a velocity readout of <1m/s. Slapping something like that together would be a lot simpler than building a special space plane, so I may just give that approach a whirl, so to speak....

I'll take that as a no, in which case nevermind. Deadstick landings in planes are easy, but building a whole new plane just to show you that is boring.

Can we keep our engines/RCS attached if we can show using the resource tab that we didn't use them at all? Jettisoning all the engines from a plane generally makes it unflyable because of how it affects the center of mass.

I just submitted this for the KSP Weekly challenge to land on Duna without using oxidizer, but since it's an SSTO and I landed it back on the KSC runway, I guess it makes a pretty decent K-prize entry as well!

Domo, sensei!

Thank you!

I ejected from Kerbin on Y2, d164, which is the first such window, but in hindsight I don't recommend that one. I kept arriving at my second Kerbin encounter too early. These routes were figured out by @PLAD, who has a series of them listed in his posts. I believe the second window was right around the first day of year 4, but if you contact PLAD or look through his post history a bit, I'm sure you can find the exact number. If you just look at how the ejection burn is set up in my album, you can see what it should look like in terms of how the bodies are aligned.

Please note: OP did acknowledge my actual score in response to this, so the matter has resolved very much to my satisfaction

Just dropping a new post to tell OP that I'm finished with this challenge. Please see my post directly above for details...

OK, here's my final entry. Total dV expended from LKO-Laythe ground-Kerbin ground: 3390m/s. Here's the final album: http://imgur.com/a/rkYEZ Don't know why it won't embed, any advice on that would be appreciated. I flew this whole mission by hand with a Nintendo controller, and aside from KER my only computational aids were a calculator and a couple of Excel spreadsheets I made. My plane ships 12 Kerbals as required and makes LKO with 4966m/s in the tank. It weighs about 105t on the runway, with a dry weight of around 43t, and uses 5 Rapiers + 4 Nervs, It took a total of 1263m/s to get to a Jool encounter, 1304 to get to low Laythe orbit, 1308 to get to the ground on Laythe, and 2371 to get back to low Laythe orbit. Outbound, in addition to a slightly messed-up version of the Plad KEKKJ assist route, I used 4 successive encounters inside the Jool system to get to a survivable Laythe atmospheric entry, as illustrated in the album. From there all it took was an 8m/s de-orbit burn to get to the surface. My best performance among many attempts getting back to LLO from there was 1033m/s for a total of 2371.From there, I was ultimately able to get back to a Kerbin transfer orbit using Tylo for 681.5 m/s. From my initial Jool transfer orbit, which hits the top of Kerbin atmo at a blazing 4100m/s, I swung around Kerbin to drop to a slightly less than 2:1 resonant orbit, then did a 140m/s DSM near the subsequent solar apopapsis to raise my PE back to Kerbin's orbit and set up another Kerbin encounter there. I thought that would be enough to give me a survivable aerocapture, but as it turns out even that ~3600m/s entry was still too fast for me to get captured without something exploding. I ended up having to do a combined aerobraking-gravity assist maneuver from there to drop to a 3:2 resonant orbit, requiring another 90m/s DSM to finally get to a survivable Kerbin aerocapture. From there, it took only another 15m/s for me to get to LKO and then the ground. Sorry, I did not land on the runway, although with enough tries I'm sure I could have. Between the tight heating envelope for re-entry and the lousy aerodynamic trim of my ship at that fuel level, I just ran out of patience trying to deadstick it to the exact right spot. I really thought I could do better than this, but clearly I underestimated how big a problem re-entry heating would be in this version. If I were going to do it again, I guess I would have more shielding, radiators, aerobrakes, etc., although sticking all that stuff on an SSTO spaceplane is kind of inelegant IMO. Perhaps the Mk3 parts would perform better also, as that Mk2 cockpit really got hot quickly. In any case, This run beat the current leader by 635m/s, but I believe that with a more heat-resistant design and somewhat better planning the 3000m/s mark is definitely attainable. I hope somebody comes along to prove that true, but missions like this are a big commitment . For those new to this kind of stuff, I think the album will illustrate a couple of useful strategies for saving fuel, and I hope somebody will find it helpful in that regard. On thing I'd like to point to in particular is the strategy of using a combination of gravity assists and DSM's to climb a ladder of resonant orbits out of your parent body. Using this strategy, you can get pretty much anywhere from LKO for <1500m/s, around 1377 to get to Jool capture, using only Kerbin for gravity assists. Juno used this strategy, and I made an album about it a while back: http://imgur.com/a/XQSnn. Off to make another Duna spaceplane....

I think the way around that would be by starting that second burn before touching down, and just making sure that your TWR on Duna is <1 at 25% throttle. Nothing in the rules says you have to stop burning just because you've touched down. Also come to think of it, I've built a Duna-and-back capable SSTO in the past. Taking that to orbit happens at full throttle the whole way, after which ejecting to Duna on the nukes at >20% throttle the whole way would probably just be a matter of working out the right timing. One could then do a powered touch-and-go on the landing leg, never going under 20% throttle, and take right back off into Duna orbit and back home. I guess for that the hardest part would be landing it deadstick on Kerbin directly from the transfer trajectory, but I actually just a couple of days ago (as part of @Joseph Kerman's challenge ) managed to aerobrake into Laythe with a spaceplane, from a just survivable atmospheric capture into a 50X52 km orbit, using only 1m/s of dV to circularize at the end. once I'm done with that challenge, maybe I'll try that approach to this one...

If you're going to go to such lengths to make this difficult, then you really ought to explicitly outlaw McJeb and other fly-it-for-you systems like Precise Node, because making that sort of thing trivial is what they're all about. Also, I could easily cheat my way around these rules by using a tiny engine at full throttle for my orbital transfer stage, so if you really want to go this route then you ought to specify some minimum TWR rather than throttle or thrust limiter setting. Why not just use the rocket equation? LN(wet wt./dry wt.)*ISP*9.82? Fuel is 0.5t/100U. I mean, I know this is rocket science but that part's pretty easy! RCS thrusters obey the rocket equation like everything else, so I'm not sure why it's too complicated. You could always make people calculate the dV based on the otherwise dry weight of the craft to insure they get no extra dV for the convenience of using RCS. Disallowing it only makes the process of correction really tedious because you have to keep re-orienting your ship to make small adjustments. Anyway, I'm not trying to be a wet blanket, but I think with a little more thought this could become a fairly interesting challenge. However IMO you are not quite there yet.

I would say that landing a spaceplane on Duna is up there among hardest things I've done. http://imgur.com/a/oKMLa The whole bouncing off the ground and then landing upside down and exploding thing is just murder. Also too the very thin air. Doable though! And getting home is a total breeze by comparison.

FYI

I hardly consider 100 Kerbals to Duna Budding! Seriously, If you landed something that size on Duna horizontally, you're doing really well! I haven't had a chance to download and look at your ship yet, but I think I can help you on the getting anywhere score: 1) Behold, the rocket equation!: dV = ln(wet mass/dry mass)*ISP*9.82. It's really pretty simple to use. To make a handy Excel spreadsheet, put your engine ISP in cell A2, your dry weight in B2, your starting fuel (units of LF + Ox if applicable) in C2, and your ending fuel in D2. Then paste this formula into E2: =LN(($B2+(C2*0.005))/($B2+(D2*0.005)))*$A2*9.82 and Voila! now you know your deltaV for whatever quantity if fuel you want to burn at a given ISP and dry weight. 2) If you want to know how much dV it takes to get from A to B, take a gander at this: Between those two things and knowing your TWR in local gravity you can easily figure it out. Unless of course you want to get into gravity assists, but that's a topic for a later post on this thread.....

I wouldn't have noticed that doing what I was doing, so I'm guessing it's the same since the last time I went there.