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Eve Landing and Return in Caveman Style


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The Caveman Challenge involves playing without upgrading any facitilies. With these restrictions, maybe the most difficult task is to land a kerbal on Eve, plant a flag and safely return the kerbal home to Kerbin. But I take the challenge and will give you updates about my progress. You can find the original caveman challenge here:

Rules I set for myself:

  • No facility upgrades
  • No mods
  • No DLCs
  • No cheats after starting the challenge
  • Assembling on ground and in orbit via docking and EVA construction mode is allowed
  • Normal difficulty settings
  • Starting with level 0 Kerbals
  • Crafts should be visually connected (offset wheels connected only by struts are OK)
  • Save and reload is allowed
  • All Kerbals must survive and be brought back home
  • Using external launch window calculator is allowed

Deviation from the rules of the original caveman challenge:

  • All twenty technology nodes reachable in the caveman challenge already unlocked via cheat menu
  • Sufficient money cheated via cheat menu

Challenges with this Eve return mission:

  • Best engines for Eve not available
  • No maneuver nodes
  • No patched conics
  • 30 parts and 18 tons limit on launchpad
  • Kerbals cannot exit command modules unless on Kerbin
    • Kerbal must be on a ladder or on its own until landed on Eve
    • Kerbal can enter a command module though
  • Probes core can only hold position
  • Limited information about orbit
    • Only height of apoapsis and periapsis
    • No information about inclination or time to apoapsis/periapsis
  • Eve is out of reach of CommNet
    • Unmanned craft can only switch on/off SAS or enable/disable engines at full thrust
  • Transfering fuel is not possible: Fuel tanks must be launched full on fuel to orbit
  • No ISRU possible
Edited by EveMaster
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Part 1: Launching Center Part of Eve Ascent module

Due to the launch mass and part restrictions the craft for this mission will consist of many parts that will be docked an attached together using EVA construction in low Kerbin orbit. The first payload for the orbital construction is a FL-T400 with 6 other FLT-T400 tanks radially attached via decouplers. With 15.9 tons and 13 parts this is quite a challenge to put into orbit in caveman style. Note that I cannot use any of the fuel within these tanks because fuel transfer is not unlocked in caveman mode. It would be possible to construct this in orbit using EVA construction since this is the largest fuel tank a kerbal can handle in zero g but getting it up in one piece has the advantage of perfect symmetry.

Ground assembly works by multiple driving craft, all within the weight and part limits, from the launch pad to the crawlerway and then docking them together before launch. First, I attach nose cones in EVA construction mode because they did not fit within the part limit. Then I dock vertically with the Skipper engine stage. To the skipper engine stage I then dock 4 radial stages with SRB-rockets and fuel tanks. To fine adjust the height for docking I can change the suspension settings of the wheels.


The only available powered wheels are a bit underpowered and they often break when driving over the transition between launch pad and crawler way. So I send an engineer kerbal to orbit and back to get him to Level 1 and repair the wheels.

Finally, I have docked everything together and can decouple the temporary parts with the rover wheels. For the top containing the payload I have to detach the struts and the wheels using an engineer because they are not attached to a decoupler. After sorting the staging I can ascend to orbit.


The fuel crossfeed from one of the fuel tanks does not work for unknown reasons. On the other side with a symmetrical setup, it does work though. So I have to attach two fuel lines to fix this.


The ascent to orbit is a pretty normal ascent with a shallow ascent profile. During the top heating I have to throttle down a bit to avoid overheating of the probe core. I launched this part unkerballed because the command pod is not in its final position and you cannot move a command pod with a kerbal in it and the kerbal can't leave it while in orbit. The probe core only supports holding position so I have to manually track the prograde direction.


I reached orbit with 145 m/s left. My next launch will bring the engines for the Eve ascent to orbit.

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Part 2: Getting More Parts for the Eve Ascent Module to Orbit

Another big launch. Two vertically docked stages and 6 radially attached ones. After a lot of ground assembly and about 20-30 repaired broken wheels the launcher is finally docked together. The wheels of the radial stages were originally attached to a decoupler on the bottom of the middle fuel tank. To replace them with nose cones, Bill attached landing legs, which he will have to remove before launch. Bill also had to attach the nose cones on the top stage on the launchpad because of the 30 parts limit.


With a TWR slighly above 1, the craft is barely able to take off the launchpad. It has 6 Swivel engines and 1 Reliant engine on the center stage. Originally I planned it the other way round, but mixed up the two types of engines. Now it is too late to fix it. This way I have 1.25 tons more weight, less thrust but also more gimbal. 12 Fuel lines were needed to make the fuel crossfeed work. The staging of the docking ports for the last three stages does not work, so I have to manually decouple them.


As no engines are detached, the TWR is quickly rising and I can coast to space to meet up with the other craft in orbit.


After circularization, I fix the small inclination difference by visually aligning the orbits on a descending or ascending node. One orbit later, the craft are docked together. Sorry for the dark pictures, but because the craft in orbit does not have any electricity generation, I better hurry up. 6 of the fuel tanks of the new craft are still full, but the center fuel tank is only partially full.


On the launchpad there is quite a mess from the parts, that were used for the ground assembly.


The next launch is a launch without ground assembly. This rocket has a high TWR but no gimbal and can only be controlled using the reaction wheel built into the probe core. To be able to do the gravity turn, I tilted the rocket in the editor and ignited the engines while it was falling over. The two Hammer SRB are set to 48% throttle so that they run out of fuel at the same time as the reliant engine.


One orbit later, the top stage is docket to the craft in orbit. This launch brought one full FL-T400 fuel tank, 6 small docking ports, two radial, two small solar panes, two decouplers and three Oscar fuel tanks (mostly empty) to orbit.


The next launches will bring heat shields and structural elements to attach them to orbit.

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Part 3: Structural Elements for Attaching Heat Shields

This launch contains a structural tube with 6 radially attached structural tubes that have themselves 6 structural tubes attached radially. This structure is needed to later attach heat shields to it. The nose cones are only needed to reduce drag during Kerbin ascent and will be removed later in EVA construction mode. This launch is a single vehicle, but all the nose cones must be attached manually to fit within the part limit. Bill has to get creative and create a ladder from the parts of the rover to reach the top. to be able to manipulate the small empty fuel tanks he needs the help of Valentina to extend the EVA construction weight limit.


Before takeoff Bill has to install two winglets, otherwise the craft would not be aerodynamically stable.


Docked with the craft in orbit.


Another launch with parts for the adapter that will connect the heat shield with the lander. This time there is no ground docking involved. The craft has plenty of excess delta-v but could not launch more parts because of the part limit.


The adapter is also docked to the craft in Orbit. I plan to first dock all needed parts for the lander together before reconfiguring them with EVA construction mode. That's because Bill would not be able to wait in a command module while I launch other parts since Kerbals can only exit command modules on the surface of Kerbin in caveman mode.


Next step will be to launch the heat shields to orbit.

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Part 4: Heat Shields

The 7 heat shields for the rear of the craft are stored in the center stage. The four radially stages are already attached and preparation for launch is on the way. Several winglets and fuel lines have to be installed.


Ready for launch. Only one broken wheel had to be repaired this time. One of the ground vehicle features a rocket engine, a parachute and landing lets. So it gets from the runway to the launch pad faster then just driving: very kerbal:D. This time I go for a steeper ascent to better keep the craft under control. While dropping stages the angular momentum of the rockets decreases and the atmosphere gets thinner which also makes the craft more stable.


After undocking the last stage, I notice that I have plenty of spare delta-v.


In orbit with 761 m/s of delta-v left which is more than enough for rendezvous and docking. Without KER, its hard to estimate the capabilities of a craft and I rather have more delta-v if this does not mean more complicated ground docking. It is also often hard to add more payload because of the part limit.


Rendezvous and docking with the station are easy with this much delta-v.


The next launch contains further heat shield for covering the engines during Eve descent.


This craft has also more than plenty of delta-v so ascend to orbit is pretty easy, and I don't have to be careful to conserve fuel during rendezvous. I go for a simple three stage design, all on wheels that are decoupled on takeoff. This design has the advantage that it does not need EVA construction and I only have to cross the transition between the launch pad and the crawlerway three times. So there are no broken wheels to repair this time.


However, during the approach, I notice that the station has dipped into the upper atmosphere. That probably happened during one of the last docking events. But that does not pose any real problems and after docking I raise the orbit of the station to be above the atmosphere again.


Next step will be to bring parachutes . I will also need radial docking ports and the Pegasus I Mobility Enhancer to create ladders for the Eve lander.

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Part 5: Parachutes, Decouplers and Adapters

Launch of a pretty standard rocket with 8 radial decouplers and 4 ladder elements as payload. The two conical adapters are also part of the payload because they will be used for the Eve vessel, too.


The high TWR gets the small rocket to a high speed when decoupling the first stage.


Shortly before staging and coasting to space to meet the orbital station. The decoupler is mounted the other way round to get it to orbit as well as a payload for the Eve lander.


The timing of the circularization burn is done in a way that it only needs minor correction for the rendezvous. 


8 minutes after launch the station is in sight and 881 m/s left, which is much more than needed. Docking is easy with such a small craft because the magnets in the docking ports take care of the alignment. 


The payload of the next launch consists of 36 ladder elements in 6 Conformal Storage Units, 6 radial decouplers, 6 parachutes and 2 conical adapters. To account for the part count of the payload the rest of the rocket is very spartanic. The first stage is just a Thumper solid rocket booster. The second stage has a Terrier engine. The three Oscar fuel tanks within the fairing are used for extra fuel and as attachment points for the parachutes. This rocket has no extra reaction wheels, no extra batteries and no way to generate electricity. Even its engines can't create electricity. The 10 units of electricity would only keep the probe core alive for 8min 20s while active. By putting it to sleep mode, whenever it is not needed, I can save some electricity. At the start I tilt the rocket over and then quickly switch the probe core to sleep mode. Some more thrust from the Terrier engine is needed to raise the apoapsis, followed by a well timed circularisation burn to meet up with the orbital station.


Now all parts needed for the Eve lander and ascent stage are docked together. At the bottom you can see the last two launched modules with the radial decouplers and the parachutes.


The next step is getting Bill Kerman to orbit and then rearrange the rocket parts into the correct configuration for the Eve lander. I will also launch an orbital tug equipped with RCS to redock parts of the vessel into the correct configuration.

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Part 6: Rearranging the Parts of the Eve Lander

Redocking and reconfiguring the craft in EVA construction mode took longer than expected. That's because of the limited range of the EVA construction mode and because a lot of temporary reconfiguring was needed to get to the needed parts in the correct order. There were also a lot of parts from the launches that were not supposed to be part of the Eve lander.

Bill holds onto the ladder on the rocket while it launches into orbit. A small solar panel serves as a foothold. During that launch I have to be careful that he does not fall off the rocket nor overheats due to a too low ascent profile. The first stage with the reliant engine and the Flea SRB has no engine gimbal, so I slightly rotated the reliant engine in the VAB to have a permanent "gimbal" that offsets the drag created by Bill.


Decoupling of the reliant engine stage. The TWR of the Terrier engine stage is just enough to get it into orbit.


Deployed the fairing after reaching space.


Docked to the craft in orbit.


Decoupling the nose cones in EVA construction mode in suborbital trajectory to deorbit them. After decoupling going back to the main craft making sure Bill does not fall off the ladder.


Nose cones in suborbital trajectories.  The periapsis is low enough so that they get deleted.


Another run to deorbit nose cones. A terrier Engine with an attached fuel tank is also deorbited.


Some reconfiguring has already been done. Some full fuel tanks and engines have been attached to the Eve Lander to the right of the center of the craft.


I noticed that spent decouplers cannot be reused when reattached in EVA construction mode. So I launch a new decoupler. With this launch I also bring a fresh EVA jetpack for Bill.


Constructing the connection to the top heat shield. Bill attaches a radial decoupler, an Oscar fuel tank and a small docking port on each side of the command module. Then the tug  attaches the adapter for the docking port. This construction has the advantage that it can be decoupled and then does not produce any drag during the ascent on Eve.


Attaching the top heat shield. The heat shields are attached to the stuctural tube section and therefore perfectly symmetrical aligned.


Another launch is needed do launch another 1.25 m heat shield for the center engine that I missed during the heat shield launch. The center engine will be protected by a 0.625m, a 1.25m and a 2.5m heat shield. That much heat protection is probably not needed but the main reason for this is to give an offset to the 2.5m heat shield so that it does not clip into the other heat shields.


Deorbiting unneeded parts of the craft. I probably should have deorbited all unneeded parts early to make orbital construction easier.


Attaching the ladders to radial docking ports. I noticed that you can place the ladder elements closer to each other if you take them directly from a container instead of taking them from a point where they are already attached. On the opposite side, I also create a ladder for symmetry. This also gives me some redundancy and in case I land on a slope I can use the ladder that does not have any overhang.


Bill leave the craft taking with him further unneeded parts.


Bill has savely landed in the oceans.


The Eve Lander in low Kerbin orbit. On top there are some fuel tanks with some fuel left from one of the launches and the orbital tug. The radially attached docking ports and other elements on the lander are only temporary and will be removed before going to Eve. 


The next step will be to bring the Eve return vessel to orbit that is used for the transfer from low Eve orbit back to Kerbin.

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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.




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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.

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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.

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