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After a few days After The first Atlantis Launch They Had the second time they had a crew To Test The Newly Made robotic arm It is Told That It Is Hard to find and Build In a few hours They will return for a runway landing The Last flight til now Was Unmanned and Landed Near By the KSC And Tried to Land at the Runway But didn`t have enough runway space for a landing The Next Part will be in a few hours

I'll be making a challenge out of this in the near future all being well, but with imgur hating me at the moment, (can view images hosted there, but actually using it myself is beign a bit temperamental atm), i want to get the writeup done ASAP. My problem was i'd totally overestimated the antenna capabilities of a probe i sent out, it had allready done a quick pass over minimum before going out for an even flyby, missed gilly on that run but then setup for a Duna intercept, as MJ was doing the the hohman burn i noticed my come line was red, a quick glance at the signal indicator, a lot of swearing, and some furious looking at the orbits of everything. Followed by more swearing. The problem was that the probe was inside eve's orbit, in front of Kerbin in it's orbit whilst Duna was behind kerbin and falling backwards, it would be almost on the opposite side of kerbal by the time of intercept. That created a real conundrum. There was no way a probe launched the normal way could beat my existing probe to duna, it would be there in a little under 200 days and the best solution i could come up with still looked like a 100 days more. But there was an answer. I could launch on a retrograde intercept trajectory so i went around Kerbol the opposite way to all the planets, and my probe. Eventually, (as in when i got attempts that got that far) i determined that would take some 166 days. Doable. I won't detail my failures here except to say that roughly a dozen configurations boiled down into 5 successive designs, (most intermediate configurations where getting to orbit problems), the first attempt fell so far short of the dv requirements it wasn't even funny. To be fair i had never tried this before, (if anyone else ever has please pipe up now, or have i got a KSP first?), save with mun/minmus missions back when MJ wasnt available just after releases, and the dv comparisons aren't even close. The second attempt was more serious, i'd done some proper looking into the numbers, but between a few mess ups still fell short of the amount needed for a duna intercept. Back to the drawing board, (these were all sim flights, i.e. revert to VAB). This led to DER-3#, my first true BFR, at 4.6 kilotons in mass and a little under 700 parts. it finally had what it took to get me onto a duna intercept. In case your wondering, whilst i had an imperfect transfer window adding a bit to the dv it totaled up to about 19 kilometers per second. No you didn't misread that, kilometers per second. Let that sink in for a moment, thats how seriously dv hungry retrograde trajectories are. I knew as soon as i finished the intercept burn i wasn't going to have enough dv to decelerate at the other end, but i went out there with the simulation to find out how accurate my now well researched prediction of the dv required was going to be. Turned out spot on. This resulted in DER-4#. 7.1 kilotons in mass and just over 900 parts. It made the intercept, it even had enough dv to decelerate, but then i found i didn't have enough solar power to run the ions at full, so i flew through duna SOI before i could make the 14 kilometer per second decel burn required. Yes 14kps dv to decelerate. These retrograde trajectories are a killer on the dv requirements. So DER-5# was born. 7.35 kilotons in mass and a mind boggling 1007 parts. Early test flights ran into problems with unplanned disassemblies of the ion stage, (i thought i'd built it with the biggest round tanks then clipped radials to boost capacity per stage,but clipping issues created stresses which had predictable results when enough mass was above them and a decoupler was fired below them). Thats when i discovered what i'd mistaken for an ore container was actually a 1.25m xenon canister. Rebuilt with that with no clipping and joy it worked. Sort of. The rebuild of the ion stage meant that whilst peak TWR values where similar to the old form, with more mass in each stage it stepped up at less frequent intervals. (Initial duan decel attempt resulted in leaving duna SOI with 3.1kps still to kill). However DER-5#, unlike 4 didn't have to have the rotation angle babied every couple of minutes to retain decent thrust so i was willing to do somthing that would have just been too much hassle, (and created other issues too), with that form. Namely start the decel burn outside duna SOI. Doing so would allow me to shed enough velocity to increase my transit time of Duna enough to complete the burn. Worked like a charm, and despite expending somthing like 35kps i even had 6 and a bit kps of dv left over for duna maneuvering. For anyone at squad who's remotely interested in things that made this a problem build in some way, (mostly what inflated the part count the worst), here's a breakdown of worst parts. Sepetrons, with such large boosters i find you need sepetrons top and bottom to stop the engine on the bottom hitting things or getting shoved into the exhaust but you need more on the top so it yaws at the desired rate and in the desired fashion so aero then keeps carrying it away. Thats 6 sepetrons per booster. on smaller designs thats not an issue, but this has 5 radial mammoth stages followed by an in line mammoth stage (2 each and i'd have preferred more because 2 where too anemic but hand placing that many was too much of a pain), followed by an in line core rhino stage (8 sepetrons here), followed by another 6 on each radial rhino stage. The LV-N fuel stages i found got away without sepetrons but the switchover from LV- to Ions needed 8 more because they tended to be sticky. Thats a total of 200 sepetrons. Most on radial stages. A better solution is needed for BFR's. Also sepetrons really need to autostage position properly in the VAB, repositioning that many sepetrons was a huge pain. 2.5 and 3.75m LF only tanks and 2.5m LV-N engines. As it was each engine "pod" for the LV-N's was 5 parts, (girder, LF tanke, Nosecone, Engine, Fuel line), but to get enough TWR i needed 12 of the buggers. Being able to use a smaller number of 2.5m parts here would have saved 10's or parts, and if i'd had 3.75m LF only tanks i could probably of ditched all the radial mounted LF tanks and still got more LF fuel carriage. That would have ditched me another 168 parts. meaning in combination with 2.5m LV-N's i could have saved a potential 200 parts there too with the use of certain things i didn't have. The ion stage is a bit more awkward to critique. Mostly because whilst i can think of several ways it could be improved, i'm not sure i would have had the tech for them. More girder lengths at the tiny cubic strut scale would have helped as each ion engine mounting arm has somthing like 8 tiny cubics thrown together. Ultimately 1.25m Ions with the significant reductions in the number of engines needed would have provided the most benefit. The tankage was part heavy, but for an odd reason. After discovering the 1.25m xenon tank i found that the higher weight of the 1.25m as opposed to 0.625m decoupler necessitated a total xenon carriage increase. I could have used 2 1.25m tanks at each step for this, but the ion stage was allready rather too long, doing that would have created serious issues. So i felt forced to use radial tanks. I don't think 2.5m xenon tanks would have helped, (though they'd be nice overall if we got 1.25m ion engines), as they would probably have carried too much fuel and especially the decoupler penalty would be even greater. IMO the issue is that xenon fuel is insufficiently dense. It makes carrying large amounts of it really volume intensive and to keep single axis craft dimensions under control on the launchpad your thus forced to adopt part count inefficient solutions. After that you've only got the niggles, (see below), and the potentially major savings that could have come with 5m stock parts, but again i doubt i'd have had those unlocked even if they'd existed. Beyond that only a few minor niggles. Not having the longest girder locked behind an endgame tech would be you know, cool. and 3.75m nosecones sop i could drop the part count from 2 to 1 there would be nice. Now for those pictures detailing the stages of the successful run, some will have comment underneath, some won't. Be warned there's a lot though so i am spoiler tagging this for obvious reasons.