EveMaster

I did a fully recoverable mission to Eve and back in 2019 with suborbital docking. Mammoth engines are indeed the best option for this, because of the best thrust to weight ratio. Taking off from the highest possible point is important to not waste fuel in the lower parts of the atmosphere. It is also important to have enough reaction wheels and RCS to be able to dock quickly before falling back into the atmosphere. Good Luck with this truly hard challenge! My design will probably not work as good in the current version of KSP 1 because back then the weight of the Kerbals did not count to the total weight of the ship and the Crew cabin modules I used were also lighter.

Cool Challenge. I guess it's also allowed to transport the parts to the launchpad using the 1.11 cargo containers? For the scoring system with celestial bodies, do you have to do a flyby, get into orbit around the planet or moon, land or land and return back to the surface of Kerbin?

That's a nice idea for a challenge! You can install the Didymos mod from this challenge for the real Didymos system in KSP: I played with this mod and managed to knock Dimorphos out of Didymos orbit with the impact of a stage containing multiple Mammoth Nerv engines. For maximum impact velocity, I planned the impact from retrograde Kerbol orbit with an apoapsis beyond Jool. If I remember correctly, Didimorphos (the smaller body of the Didimos system) is an order of magnitude larger than the largest stock comet in KSP. So it should be possible to get it captured in Kerbin Orbit, but it really is a big challenge. Edit: Numbers of Didimorphos in the KSP mod: Mass of Didimorphos: 4 million tons (50% minable asteroid ore) Orbital velocity of Didimorphos around Didymos: 0.2 m/s Numbers of my Didimorphos impact mission: Mass of impactor: 552 tons (stage with 19 Nerv engines) Impact velocity relative to Didimos: 23.7 km/s Escape velocity after impact: 0.6 m/s Such a high impact velocity is at the edge what KSP is able to simulate, because of the large distance traveled in a single simulation step. When I repeated the impact, some times it did not dectect the collision or Didimorphos was completely destroyed on impact. Docking and asteroid mining for fuel surely is better than an impactor for getting Didimorphos captured in Kerbin orbit.

I managed to get to 120090m, thats more than 30km above the atmosphere. I did not drop anything and landed back on the surface without damage.

A cargo bay does not offer any heat protection at all. I experienced that the kerbal even overheats faster in the cargo bay compared to just grabbing to a command pod. I guess this is because heat can be radiated and convected away from the Kerbal easier this way. Or maybe it is because heat from the spacecraft is radiating less towards the Kerbal when standing on a ladder. For launches without gimbal on the first stage, I slightly tilted the first stage engine to get a "permanent gimbal" that offsets the assymetrical drag caused by the Kerbal. I put a small solar panel as a foothold so the Kerbal does not slip off when golding to the rocket. To be able to successfully launch long rockets with bad aerodynamic properties, it helps to make it more rigid with rigid connections and autostruts. It also helps to take a steeper ascent profile and to break the sound barrier further up in the atmosphere. For timewarp in Caveman style, the Kerbal must let go the space ship. After timewarp, use the EVA pack to get back to the ship. Keep the drift under 100 km to be able to use the target marker to find the way back. For the way back to Kerbin, the Kerbal can enter a command pod. This is possible, only exiting a command pod is restricted in Caveman mode.

The range for setting another ship as target is 100 km. If you time your launch correctly, you can get this close to a ship in orbit during launch and use the target marker to rendezvous on the first orbit. Especially in Caveman mode this is much faster than approaching over multiple orbits but usually costs a bit more fuel because you have to act quick, which means less precision.

There is a fix for the undocking bug. You cannot undock because the docking ports are in an inconsistent state. You have to edit the save file to fix it. The following steps still apply even though this thread is some years old:

I think that is the best and easiest solution. They cannot be used while moving through the atmosphere but still allow for ISRU.

Nice challenge idea! But ISRU without radiators is not really possible without trickery, the production rate drops to zero. Maybe you disallow using radiators while flying through the atmosphere but allow deployable radiators while on the ground for ISRU.

Part 18 and Final Part: Return to Kerbin To know when the transfer window back to Kerbin is, I again consult the launch window planner. I go rather late in the transfer window because then Eve and Kerbin are closer together, so I arrive rather too early at Kerbin. When arriving too early I can correct for this by first going higher than Kerbins orbit, when arriving late I can only try to get a Kerbin encounter several orbits later. I don't directy eject back to Kerbin but go into an elliptical orbit first. For that I just guess the time when I have to start the burn to later get the correct ejection angle. The top fuel tank is now emtpy and I decouple it in a suborbital trajectory. I raise the periapsis again to be above the atmosphere and do the ejection burn at the next periapsis. I don't count delta-v this time but just guess when to stop the burn. From previous Eve missions I know that after getting an ejection trajectory from Eve it only needs a small burn to get to a Kerbin transfer trajectory. After leaving Eve's SOI, I notice that I still have to burn a bit prograde to get an Eve encounter. By trial and error I find out that I have to go a bit higher than Kerbin's orbit to get an encounter when crossing Kerbin's orbit the second time. To make it easier to get an encounter, I eliminate my relative inclination to Kerbin about halfway to Kerbin. When I reach Kerbin, my trajectory goes outside of Minmus' orbit. I burn radially to get an encounter with Kerbin for aerobraking. The altitude for aerobraking that I go for is higher than in this screenshot. If found out that 49.5 km works best. Aerobraking at Kerbin into a retrograde orbit. The altitude is as low as I can go without exploding. The Terrier engine gets very close to its temperature limit. After aerobraking, I only need a small retroburn to get captured in Kerbins orbit. In this screenshot it looks as if I'm already in a stable orbit, but I still need a small bit of retroburning. Without patched conics it might seem that you are in an orbit, but you are actually not because the apoapsis is outside the sphere of influence. With the apoapsis at the height of minmus orbit, I should be safe. Correcting the inclination of my orbit to 0 using Mun's orbit as a guide line. Aerobraking into a lower orbit over multiple orbits. Passing Bill's ship with a relative speed of 4620m/s because Bill is in a prograd orbit and we are in a retrograde orbit. Bill has been in low Kerbin orbit for all of the Eve mission because I forgot to bring him down. So I deorbit Bill's craft and come in for a landing close to the KSC. Landing Bill in the ocean next to the KSC. Preparing for the landing of the ship that has been to Eve. Only a small amount of fuel and electricity is left. The deorbit burn has been performed. There still it a tiny bit of fuel left in the part of the ship that has been on the surface of Eve. Approaching the Kerbal Space Center from retrograde direction. Burning the last drops of fuel. Now the ship has slowed down. I still wait a bit deploying the parachutes. Gliding down to the Kerbal Space Center. The craft landed on the side of the runway. Valentina and Jeb seem to be happy being back on Kerbin and pose for a photo in front of the Eve return craft. The same screenshot without GUI. Screenshot of the mission report for recovering a ship that has been on the surface of Eve with the un-upgraded buildings or the Kerbal Space Center in the background. The caveman style mission to Eve's surface and back has now been successfully completed. I hope you had as much fun reading this mission report as I had playing this mission.

Part 17: Getting Back to Low Eve Orbit Once Valentina has entered the command pod, I decouple all ladder elements. Then I prepare the staging. I use aspargus staging with decoupling two opposite fuel tanks at the same time. The priority of the fuel tanks is set up in a way that each stage first uses the fuel in the top half to improve stability. In the first stage there are 6 Reliant engines for better performance and one Swivel engine in the center for gimbal. I also open the window for the Terrier engine already because I have to switch on this engine manually later on. The staging does not switch on this engine on due to the way I assembled the craft. The root part is not the command pod, but the central fuel tank. This central fuel tank is also the fuel tank that is only partly filled, what I only noticed when departing from low Kerbin orbit. I launch up vertically with full throttle. I have the SAS set to hold position, but I have to constantly give manual input as well to stabilize the craft. Half a second without input and it would tumble out of control. The craft has no control surfaces and only the reaction wheels integrated in the command pod and one engine with gimbal for control. But I think the main problem is that the craft is no longer perfectly symmetrical because of parts migrated due to saving, reloading and time warp. However, I can keep the craft steady and decouple the first two side engines and fuel tanks. When decoupling the second stage, the craft rotates to the wrong side. But I am able to regain control. I now start with the gravity turn. Decoupled the last side stage. The Swivel stage burns only very shortly because the fuel tank of this stage was already nearly empty on launch. I decouple the Svivel engine and now fire the last stage which is powered by a Terrier engine. Now holding prograde and continuing to build up speed. I decouple the nose cone when leaving the atmosphere and a align the direct approach to the ship in orbit. The trust to weight ratio of this stage is so good that I don't have to burn the engine all the time. I reduce my relative speed while approaching the ship in orbit. Now the orbital stage is in sight and 34m/s of delta-v are left which is enough for docking. The ascent was not the most efficient. If I just tried to get up in any stable orbit without direct rendezvous I could have saved a bit of delta-v. Docking was more difficult than expected. I aligned perfectly and just would not dock together. For small crafts like this docking without RCS should not be a problem. Then I noticed that I had turned the docking force down to 0 for the last redocking in orbit to avoid the parts from drifting away. I turned the docking force back up and then the docking succeeded instantly. Now I just have to get Valentina and Jeb safely back to Kerbin to finish off this mission. Two things make this more difficult than planned: I used up some of the fuel of the extra fuel tanks already for deorbiting the Eve lander. And I also forgot to bring solar panels for the return stage. The engines of this stage also produce no electricity. Fortunately I don't have any probe cores on this craft that constantly draw energy. I just need the energy for SAS. I will have to turn the strength of the reaction wheels down and conserve as much electricity as possible.

Part 16: Landing on Eve The Eve lander and Valentina will land seperately because otherwise it would be too hot for Valentina even if she were protected by a heat shield. Jeb will have to stay in orbit because the lander only has one seat. I deorbit the lander using the Poodle engine. Periapsis is around 68km to save fuel. The lander would survive a periapsis of 0km or even below that. After doing the deorbit burn I decouple the orbital stage and quickly get it up into a stable orbit. When that is done I switch back to the Eve lander. I do not have to worry much about the ship during reentry because it is well protected by heat shields. The lander even survives 4x pyhsical time warp during reentry. The amount of ablator on the heat shield is tuned to the amount needed to avoid unneeded mass. The seven large fuel tanks behind the heat shields are all empty. They were not intended to be on the lander but I could not undock them because of a bug. They do not cause any problems however. I disable SAS during reentry. This way the ship wobbles more, but I found that leads to more reproducible landing locations. The lander is designed to passively stabilize in the correct orientation because by the drag of the components. After decoupling, the lander begins to tumble around 20°-30° from retrograde. If I were to redo this mission I would probably add a reaction wheel to this stage to better control this tumbling. All the reaction wheels have been decoupled with the heat shield, only the integrated reaction wheel of the probe core and the command pod remain. By timing the decoupling, I have a little bit of control over the landing position. I also activate SAS when the lander tumbles in a the correct direction for body drag to direct me towards the landing position. At first, I deploy only one parachute. The asymmetrical parachute configuration gives me another few meters of drift towards the landing location. Then I deploy the other parachutes and decouple all heat shields. Landed at an elevation over 6000m. This took me around 50 tries. For more then half of them I targeted the wrong mountain. Then I used the small lakes to correctly identify the correct mountain for landing. I deorbit the empty fuel tanks and the Poodle engine and dock the remaining parts together again. Valentina stores her jetpack in the orbital stage to save on mass before deorbiting. The deorbiting stage can only hold prograde because the probe core has no connection to the KSC and Valentina can't directly control it while standing on a ladder. However, she can control the craft in the pro/retrograde, radial/antiradial direction by walking up or down the ladder against a solar panel. This generates a force that rotates the craft. The craft started to burn with a radial component so it nearly raised to nearly 100km height. To get into the atmosphere, Valentina rotates the craft to burn more radially. Most of the orbital velocity has been cancelled out. Waiting to drop a bit further into the atmosphere before burning up the rest of the fuel. Then Valentina jumps of the craft. She quickly falls to denser parts of the atmosphere so she slows down and does not overheat. Valentina uses her parachute to fly down to the Eve lander. Valentina arrives at the Eve lander. The Eve lander has a mass of 42 tons as it stands now on the surface of Eve. That's more than twice the launch mass limit of the KSC launch pad in caveman mode. Another screenshot with Valentina and the Eve lander, this time without GUI. Valentina goes up the ladder to fetch an EVA experiment from the command pod. Planting flags is not possible in caveman mode, so instead she plans to do some experiment. Valentina having fun with the EVA experiment which is teeing off a golf ball. The next task is to get her back into orbit and dock with the orbital craft.

Part 15: Transfer to Low Eve Orbit Now that the problem with the ladder is sorted out, here is the mission report about getting from low Kerbin to low Eve orbit. I used alexmoon KSP Launch Window Planner to calculate the burn needed for the transfer to Eve. Without maneuver nodes at hand I used the stock delta-v display to time the duration of the burn. I guessed when during the orbit I had to start the burn so that I get ejected from Kerbin retrograde in respect to the orbit around the sun. I do not do any staging for this burn because I do not want to produce any orbital debris. After exiting Kerbals SOI I can see the orbit around the sun. Before correcting my orbit, I use Valentina's Jetback to get her back to the craft. This time the drift was less than 1km. I generally try to keep the drift below 100km so that I can easily find the way back to the ship by using the target indicator. Valentina is back at the craft. I do a combined prograde/retrograde and radial/antiradial burn to get the values of apoapsis and periapsis match the value of the launch window calculator. About half way to Eve, I cancel out my relative inclination to Eve's orbit. That is less efficient but makes it easier to get an encounter with Eve. Entering Eve's SOI. I need to burn radially to get my periapsis down and normal or antinormal to reduce my inclination. I aim to get into an orbit with around 3° inclination around Eve because my intended landing position is close to the equator but not quite at the equator. I got the periapsis down to below 20 km before undocking unneeded engines and fuel tanks to make sure they get deleted when encountering Eve. I notice that I can only undock the enigines and fuel tanks at the very back and not the fuel tanks docked directly to the structure holding the heat shields. This is a bug that often happens when doing complex docking operations where you undock and then dock back to the craft using another docking port. To limit the drifting of Valentina, I get her to a position where she can bounce off in all directions and switch of the EVA jetpack. This uses a bit more EVA fuel than just letting go from the ladder but the velocity relative to the main craft is much lower then. When approaching the periapsis I get Valentina back to the craft. The undocked parts that are not needed any more are on a lower trajectory and will get deleted soon when going into Eve's atmosphere. Retroburning at Eve's periapsis to get capured into an orbit around Eve. The captured orbit is very eccentric because I plan to spent about half an Eve year there before lowering it. This is because I want the part where the orbit passes over the northern hemisphere to be on the day side because that's where the projected landing area is. Doing a retroburn at periapsis, spending the remaining fuel on the skipper engines side. The remaining Skipper engines with the attached fuel tanks are deorbited half an orbit later. I continue to lower the orbit further using the Poodle engine. Here I undock the small fuel tanks to deorbit them. Unforunately from here on I cannot undock any further empty fuel tanks because of the undocking bug. In a 90km x 119km orbit I have spent all the fuel planned for the transfer. Not being able to undock all spent fuel tanks increased the fuel consumption. There is however still fuel in the two smaller fuel tanks that are radially attached. I don't need all that fuel for the transfer back to Kerbin so I can continue the burn using that fuel. I got to a 92km x 92km orbit. The 2km above the atmosphere give me some time so that I won't directly hit the atmosphere when doing the deorbit burn of the lander. The lander itself has no way to deorbit itself because its engines are covered in heat shields, so I have to push it into a suborbital trajectory and then quickly get the orbital stage back into a stable orbit. Valentina is now also back at the craft. She is not in a command module, so I have to get her back on the ship after every time warp and you cannot time warp with a Kerbal on a ladder. Next I have to deorbit the lander in a way that it lands at a location higher than 6km. This requires exact timing because the unmanned lander has nearly any control with a relais networks impossible around Eve.

I found a solution to my ladder problem! 11.1 introduced the feature that Kerbals stop at the end of a ladder. This feature has a bug that you cannot get from one ladder to the next after reloading. Thankfully there is an option to disable this in the general KSP settings. I can now continue with the mission in low Eve orbit without having to redesign the craft. However, I cannot continue with the current save on the surface of Eve because the elevation of the landing location is to low to get back to orbit.

As I said, that is my fallback solution. It would work in my case. There is however a mod that makes crew transfer more realistic where this would not work. Do you have any more info about this problem, when it happens and how to avoid it or perhaps links to discussions about it?

An Update on the Status of this Mission: First of all, thank you all for the positive feedback and the many likes. I managed to get to a 90km x 100km Orbit around Eve, despite some problems with undocking. The Fuel tanks attached to the heat shield and all but the small fuel tanks on the Poodle engine side could not undock. I know that is a known bug where the docking ports get in some invalid state and that it can be fixed by editing the save file but I did not want to resort to this. For the rest of the circularisation and the deorbit burn of the lander I used some fuel of the return vehicle which should have enough margins to still make it back to Kerbin. I also managed to land the Eve lander. I did not bother to land at the correct location (It should be above 6km to be able to get back to orbit). Deorbiting Valentina and parachuting down to the lander also worked. The main problem was that the ladder did not work. Valentina could not climb up more than to the first ladder segment. With a lot trying around I managed to get Valentina climb up to the second ladder element, but climbing up further was not possible. I think it has to do with time warp, reloading and/or switching vessels. In orbit the ladders worked at first and then later also had the same problems than now on surface of Eve. The ladder on the other side also does not work. Another problem I noticed is that the part with the probe core on top might not fall to the ground as expected when decoupled, but come to a rest on top of the lander if the inclination of the ground is too low. For the separation of the command module on top, I plan to attach two Spark engines so that it can fly away like a sky crane. I will have to find a solution to the ladder problem and reload a save file from orbit around Kerbin. One solution would be to attach a command module (or two for symmetry reasons) to decouplers low to the ground and then transfer the Kerbal to the command module on top. However, I'm looking for a more elegant solution first. Despite this setback, I will continue with this mission and post updates here. Below you can see Valentina trying to climb up the ladder without success.

Part 14: Fuel Lines and Getting Kerbonauts to the Ship in Orbit I noticed that the fuel transfer for some of the tanks does not work, so I have to send up Bill again to fix this by attaching fuel lines. Final Terrier stage. Docked to the craft in orbit. Bill attaches fuel lines on the side with the Skipper engines and the side with the Poodle engine. Bill has entered the command module for reentry. Coming down a bit short of the KSC when deploying the parachute. Landed in at of the mountain range near the KSC. Now it's time to get the pilots Valentina and Jeb to orbit. Bill also has to go to again because he has to remove a ladder that he forgot to detach on the last flight. Jeb can comfortable fly within the command pod while Valentina and Bill have to hold onto a ladder. To get the Kerbals to the ladders at the command module I used the latest in Caveman technology: an open fairing as a landing platform and the ladder rover as a platform to jump from. Unfortunately when Bill tried to climb the ladder it did not work any more. I hope that doesn't happen on Eve. To work around this, I attached a docking port with three batteries as a platform for Bill to stand on. Then I detached a ladder, so that Bill could grab the one above it. I then moved the platform up and repeated that until Bill was at the top. Next, Bob has to drive the ladder rover away and Jeb has to enter the command module. Liftoff. Valentina and Bill remember to put on their helmets so they won't suffocate. Staging side fuel tanks. Next staging event. Switching to target marker when the ship is 65.2km away. Relative speed is still 1324.7 m/s but the TWR is high enough to slow down in time. Bill detached the parachute to free up the docking port for docking to the mother ship. Jeb transfers to a command module of the mother ship. Bill undocks the launcher craft and reattaches the parachute. He will go back to Kerbin with this craft after the mother ship has left for Eve. Next step is to transfer to Eve and slow down there to capture in orbit.

Part 13: Final Reconfiguration For the final reconfiguration Bill launches to orbit while holding to the ladder. This craft is the same I used earlier in this mission and bring also another RCS tug to orbit. Decoupling of the small SRB boosters. For some reason Bill seems to be a bit afraid during the ride to orbit. Approaching the mothership. Docked to the mothership. When I try to undock one of the large fuel tanks that needs redocking, the Space Kraken strikes and the ship explodes. Fortunatly I a save from shortly before that I can restore. Docking the large fuel tank in between the other fuel tanks. It is a tight fit, touching all other fuel tanks and I need to disable autostruts to be able to wiggle it in place. Bill attached a docking port to the Poodle engine so that I can use the RCS tug to dock this engine and the large fuel tank to correct position. The Poodle engine is docking in place. The empty fuel tank that needs to be replaced by a full one. Docking both the full and the empty section of the return vehicle to the part of the craft that will be deorbited. Leaving the empty part where it is and docking the full section of the craft to the new full fuel tank. Docking the two full sections back in place. After having moved all unneeded parts to the section for deorbiting, Bill uses some of this remaining EVA fuel to take a selfie with the ship and the Mun in the background. He seems to be proud of what he has built in EVA construction mode. The Oscar fuel tanks are meant as structural parts only, so Bill attaches a fuel line to use this fuel to get the ship into a circular 80km x 80km orbit. The original plan was to just to deorbit the unneeded parts unmanned without recovery, but then I decided to deorbit them together with the command module. Bill did some reconfiguring so that the center of mass of the craft was lined up with the central engine. The nearly empty fuel tanks and all the attached parts created a lot of drag so nothing burnt up during reentry. The one parachute was originally meant to only slow down the command capsule, so the terminal velocity of 23.6 m/s is pretty high. But by burning shortly before touching down, I avoid any parts to be damaged. The ship is now in its orbit, ready for departure to Eve. It weights 236.1 tons which is more than 13 times the launch mass limit of the launch pad. When checking the craft, I noticed that the center fuel tank of the Eve lander is nearly empty. This tank is supposed to fuel the last stage of the Swivel engine before switching to the stage with the vacuum optimized Terrier engine. When checking my old save files, I found out that this fuel tank has been nearly empty since the first ever launch of this mission. I probably to disable fuel transfer and the fuel tank had the same priority than the last fuel tank of the launcher. I will carry on with the mission despite this problem. Replacing the complete core section would mean that I would have to completely rebuild the Eve lander part of this craft. Another screenshot of the craft before departing to EVE, now without GUI. Next I will wait for a launch window to Eve and then send up Valentina and Jeb to the craft.

My testing showed that additional kerbals only make a difference when on the ground. For some assembly in this mission I used two kerbals. The most I could use would be 5 because more kerbals are not possible without upgrading the astronaut complex.

Part 12: Getting the Final Fuel Tanks to Orbit To get more fuel to the craft in orbit, I use the well proven design that I used earlier in this mission. 256 m/s left is much more that with the previous launches where the fuel tank was directly attached to the payload. I guess this is because this launch configuration is more aerodynamic with the fairing oriented the normal way. I also was able to dock within the first orbit. I decided to recover the launcher, so I deorbited it. It needed some retroburning to avoid overheating of the engine. Also, some retroburning was needed to slow down to be able to deploy the drogue chute and parachutes. This one was close. But it was enough to slow the craft down before hitting the ocean. Another launch with the same configuration. Again rendezvous in the first orbit and docking without RCS tug. I also recovered the launcher this time. Approaching the KSC. Again overshooting the KSC and landing some kilometers behind it in the ocean. This time I retroburned a bit earlier, to deploy the parachutes in time. Third launch, again in the same configuration. This time I can't dock in the final position because the docking ports of the other parts block this position. So I choose another free docking port and will redock it later, when I have removed those docking ports in EVA construction mode. This time I also recover the launcher. Again overshooting the KSC, but still a safe water landing. The last thing to launch is the smaller fuel tank that I noticed was empty earlier. For this I go for a launch without ground assembly and a Reliant engine with two small RCS side boosters. I have to control this craft by the small reaction wheel only because it has no gimbal or control surfaces. Rendezvous with the mother ship on the first orbit. Approaching at 200m/s and still nearly 400m/s of delta-v left. Approaching the mother ship and docking to a free docking port without using the RCS tug, but by orienting both craft to face each other. Now all parts needed for the Eve landing mission are docked together in orbit. Next I will bring Bill Kerman to orbit and reconfigure the craft into its final form. There will also be some redocking needed because some parts are too heavy to manipulate in EVA construction mode.

Part 11: Engines for Kerbin Ejection Burn Another launch to bring a Skipper engine with attached fuel tanks to orbit. Coasting to space. In orbit with only 64 m/s delta-v left. After correcting inclination and slowly approaching over several orbits, when I finally reach the mother ship I run out of fuel. But this is no problem, I just use the RCS tug dock dock it into place and deorbit the probe core of the launcher. The second Skipper engine is now docked in place. I launch a rocket without ground assembly to get another RCS tug and fuel for maneuvering the mother ship in Kerbin orbit. In orbit with 1440 m/s remaining. Before going to the mother ship I dock with the engine and the fuel tank that were corrupted during the slingshot to orbit maneuver. I the deorbit it using its own fuel to let it burn up in the atmosphere. Of course, I could have just deleted it in the tracking station, but that would not have felt right to me. I rendezvous and dock with the mother ship. The Terrier engine of the last launch is now mounted in a central position and I can use it and the spare fuel from this and from previous launches to bring the mother ship down into a 72km x 72km orbit. Another launch of a Skipper engine and large fuel tank. I hope that it is now easier to rendevous with the mother ship as it is now in a lower orbit. In orbit with only 43m/s left. The mother ship is 95km away. I rendezvous and dock with the mother ship some orbits later. When docking, I have 7 m/s left. This time I don't need the RCS tug to dock, instead I orient both craft facing each other to align for docking. I use the RCS tug to then dock the fuel tank an the Skipper engine to its final position. Launch of the 4th skipper engine for the craft in orbit. 25 m/s left when approching the mother ship. With 22 m/s to spare when at the mother ship, this was the launch of a Skipper engine and fuel tank where I had the most delta-v remaining. I use the RCS tug to dock the Skipper engine into its final position and deorbit the probe core of the launcher. The original plan was to have 7 Skipper engines, but because of the difficulty of getting them into orbit I decided that the 4 already launched will be enough. So, next I will bring 3 large fuel tanks to orbit. With the launcher I have, they can be directly docked in the first orbit. I will also have to launch a small fuel tank, because I noticed that the one of the already docked craft is empty instead of full.

Part 10: New RCS Tug and First Engine for Transfer to Eve The launch of the new RCS tug is pretty straight forward with a single launch without ground assembly. Decoupling the fuel tanks and engine of the launcher while in a suborbital trajectory while approaching the main ship in orbit. The fuel tanks still had quite some fuel in it, but I wanted to avoid space debris. I'm using RCS for the rest of the way and the docking. This launch is supposed to bring a full, medium sized 2.5m diameter fuel tank with an attached Skipper engine to orbit. Three parts have been docked on the ground before launch. Coasting to space. After reaching space I deploy the fairing and do the circurarization burn. Unfortunately the fuel runs out with an apoapsis of 72.5 km and a periapsis of 64.3 km. So I decide to spin up the craft and decouple while spinning to get the payload into orbit. The rest of the craft weights only 830 kg but the payload is 12 tons, so i need to spin up to quite a high speed before decoupling despite the fact that I'm nearly in orbit. The spinning maneuver works and I get the payload into orbit. But the high g forced during the rotation permanently rotated and offset the parts. The parts seem to be float but they are still connected. Like that the parts are not useful any more. Both the Skipper engine and the fuel tank are also too large to fix that in EVA construction mode. Back to the drawing board. I increased the thrust level of the SRBs to 100% and reduced the fuel level of the first stage to reduce the gravity losses at the start of the launch. I also added more staging on the center stage. Decoupling the SRB boosters and fuel tanks. Decoupled the top of the rocked consisting of a FT-T400 fuel tank and a nose cone. I noticed that the decoupler is attached the wrong way. I will fix this for the next launch. Deployed the fairing and detached the next stage. The last stage only has two baguette fuel tanks. The fuel in the large fuel tanks is not supposed to be used. Reaching orbit with 55m/s left and still a bit of inclination to correct. For some reason the margins were much lower than in the launches where the fuel tank was not attached to the Skipper engine. Carefully saving fuel during the maneuvers I approach the craft in orbit several orbits later. Within 1km of the target the fuel runs out. I'm directly heading for the craft, but because of orbital mechanics I would not directly reach it but drift away. So I send the RCS tug to fetch the payload. Docking the fuel tank and Skipper engine. Of the 7 docking possibilities only 2 fit because the attached small docking ports would block the other positions. I placed these docking at the very top of the fuel tank so that they are at the center of mass of the side stages. But I will have to adjust that for the next launches. The first Skipper engine is docked in the correct position. Next, I will launch 6 more Skipper engines with attached fuel tanks. I plan to optimize my design and lower the orbit of the craft a bit to reliably get them into orbit.

Part 9: Fuel Tanks and Poodle Engine This launch is another launch of three parts, docked together on the crawler way. But this time the payload is two short 2.5m diameter fuel tanks instead of one medium sized one. Heating during the ascent is not a problem because of the fairing. When arrived at the craft in orbit, the RCS tug picks up the fuel tanks and attaches it to the craft. Afterwards, I deorbit the launcher. Another launch with two short 2.5m diameter fuel tanks. The RCS tug has attached the two fuel tanks at the correct position. Center stage of the next launch. In addition to the medium sized 2.5m diameter fuel tank full of fuel the payload consists of a Poodle engine. To fit within the 18 ton limit, the bottom fuel tank is only partly filled. The Oscar fuel tank is the reserve fuel. Without it would not have been possible to increase the fuel level of the bottom stage anyway. To get the payload to orbit, I deploy the fairing shortly before reaching space and flip the craft by 180 degrees. The rest of the way to the station I use the Poodle engine, but the fuel in the orange fuel tank remains untouched. The margins on this launch are narrower, so I don't rendevous on the same orbit, but some orbits later. When I arrive at the ship in orbit, I only have some fuel in the small Oscar fuel left. Also, I only have less than 1 electricity left. I then use the RCS tug to dock with the main craft. The monopropellant on the RCS tug is now almost completely empty. Shortly before docking, I realized that I had to dock diagonally to avoid colliding with the fuel tanks of the main craft. This docking position is only temporary. Before docking at the correct position, I need to do some EVA construction first. Next step is to launch a new RCS tug as well as Skipper engines with attached fuel tanks, needed for the burn from Kerbin to Eve.

Part 8: Fuel Tanks for the Transfer to Eve For the transfer to Eve, I need a lot of fuel. Each of the next launches will bring a full Rockomax X200-16 fuel tank to orbit with a small docking port attached at the top and bottom. This is the largest fuel tank that I can launch in Caveman style. It weights 9t which is exactly half the weight limit of the launch pad. The next larger fuel tank is 18t which would mean that I can attach not even a single part to it without exceeding the weight limit. The design is very simple with only three rover sections which can be quickly docked together on the crawler way. Not having to drive back to the launch pad means that for most launches I do not have a single broken rover wheel. Driving from the launch pad to the crawlerway is less problematic because there is a small drop in height in this direction. Some explosions during the launch are expected. Firing up the rocket engines sends some of the rover wheels many meters up into the air. Decoupling the SRB with the attached fuel tanks. The thrust level of the SRBs is adjusted so that it runs out at the same time as the fuel in the tanks. Second staging event. The design is very resistant to heat because all heat sensitive parts are protected by the fairing. Docked to the craft in orbit without using RCS by rotating both craft to face each other. The docking at 0.1-0.2m/s knocked the periapsis into the upper atmosphere so I will have to raise that up again using the spare fuel of the launcher. Approach for second docking. 4th large fuel tank docked in Orbit. I continue to launch fuel tanks into orbit. For all but one docking I docked without RCS. For one docking I attached the orbital tug to make docking easier. The 7th fuel tank in orbit. Now I have completed one layer of fuel tanks. This launch was special because it also contained parachutes, so that I can deorbit and recover this stage. Approaching the Kerbal Space Center. Using some of the remaining fuel to avoid overheating and to reach a speed where the parachutes can open. Gliding down on the parachutes. The parachutes just fully opened shortly before the next screenshot. Landed in the Ocean next to the Kerbal Space Center. The next launches will bring a Poodle engine and some fuel tanks for it to orbit. I plan to use the Poodle engine to lower my orbit around Eve to a low orbit. For that maneuver a high ISP is more important than a high TWR. I plan not use aerobraking because that would not work well with a kerbal on a ladder.

Part 7: Eve Return Vessel and Eve Descent Vessel This launch brings a full Rockomax X200-8 with attached docking ports to orbit. Jeb gets a bit scared during launch when the engine burs away the rover for the center stage during take-off on the crawlerway. Decoupling of the side fuel tanks. Jeb is very happy that he is approaching the Eve lander in orbit. Docked to the Eve lander. Using the tug was not necesary because the launcher contained RCS itself. Jeb thinks it's perfectly fine to fire the engines 5 seconds before impact to slow the craft down at 13g deceleration to slow down to be able to deploy the parachutes. Suicide burns should not be limited to bodies without atmosphere. Deploying the parachute while sill at 263 m/s. The parachute slows the craft down in time. Safely back on the ground. Launching of the Eve Return Vessel. Deploying the fairing knocks off the large nose cones which is convenient because they were not needed anymore anyway. I noticed that I forgot to reduce the fuel priority on the center stage. Fortunately, there is enough delta-v left anyway. Docking to the fuel adapter added in the previous launch. The launcher has some RCS as well which makes the docking easier. Docked to the Eve Lander. The return craft only has two ant engines for maneuvering because I plan to use the Terrier engine of the Eve lander for the return from low Eve orbit. The craft also has two parachutes for the landing back on Kerbin. Deorbiting the launcher. It has not enough fuel left to slow down so it is destroyed during impact in the ocean. This launch uses the same setup as the previous one but wiht another cargo. Decoupling the side tanks. The docking must be performed from the main craft because the payload has no rcs and no additional docking port. The mass of this payload is designed to balance out the Eve return vessel on the opposite site. The main Eve lander must land unmanned because it is not safe for a Kerbal to hold onto a ladder because of the heating. The Eve lander is designed to be passively stable so it can be landed without kerbal control. It is planned that the pilot kerbal uses the just launched Eve Descent Vessel to slow down while holding onto the ladder, then let go the vessel and parachute down to meet the Eve lander. The craft with the docked Eve Return Vessel and the Eve Descent Vessel. During deorbiting the launcher some retroburning was needed to avoid overheating of the engine. With plenty of delta-v left I was able to safely land even without parachutes. The next thing to do is to bring fuel and engines to orbit for the transfer to Eve.