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Tree of Life - The evolution of a spacecraft - Jool 5.5 science challenge


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After my successful Eve mission (mission report below) it's time for the next big one.

According to the rules of the challenge

it will be a Jool 5.5 on Jeb level. 5.5, because it will include, beside the 5 moons of Jool, Jool's lower atmosphere too. My original goal was to break the record of the collected science points, which is currently held by @king of nowhere, but I have inside information, that a new record mission is already on the way, and it may be finished before mine. But, after I invested hundreds of hours in this, I will do it anyway.

Since the Eve mission I made some progress in KSP.  This time I will perform some gravity assists and aerobraking too, and I will use ion engines. I used this time advanced tweakables to adjust the fuel flow and for AUTOSTRUTS, which is essential at this complexity. What is still the same in this mission too, I will do it without heatshields.

The spaceship for this mission will be the Tree of Life, and like in the evolution, not all parts will survive till the end. I designed it to reuse parts within the mission, but not for further mission. So, if you get stressed (or get in some other unwanted medical condition) when you see space debris, you may not read the further posts. It will be messy.

The parts of the Tree of Life:
- Falcon
- Jellyfish
- Wasp
- Sloth
- Tetrapus (it reminds me on an Octopus, but with only four tentacles it's definitely not an Octopus, but I don't want to get problems with copyright)
- Veterinarian
- Cocoon
and there are six uncrewed vessels without proper names.
Which will survive the evolution process?

I set a rule for myself, that all crewed vessels will have a pilot onboard. This leads to a crew of 11 kerbals (5 pilots, 3 engineers and 3 scientists). Like on the last mission, I want to minimize the number of reloads.

Here are the stats.


There are a lot of stages, and they will change through docking and EVA-construction. There will be only a single launch from Kerbin. The cost of the spacecraft is astronomical, because it has 27 RTGs and several xenon tanks, which makes almost half of the total cost. I could lower the launch mass below 1000t, but that would make the already very long mission 20-30 hours longer.

The engine specs
12x Mastodon and 8x Separatron only for the launch on Kerbin
2x Vector
2x Wolfhound
1x Reliant
1x Rapier
1x Terrier
6x Nerv
9x Cub
4x Twitch
6x Dawn
4x small electric engines for the propellers

I will launch the mission soon, but before, I want to figure out how to make videos. Videos of the most complex parts of the mission would be cool, because I could focus on the controls and wouldn't need to think about making enough screenshots at the right time, and you could become a better impression, what happens.

Edited by DennisB
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Episode 1 - Introduction and launch   (Feb 19)

Here we are again. My KSP clock shows 672 hours, and the next mission is ready to launch. According to my latest calculation, it should be possible to collect up to 94,2% of the theoretically available science points of the Jool system, if my calculation is correct. I'm sure, you all are curious to see the rocket after that long time waiting.


Here you can see almost the whole zoo in their launch configurations.



In the left Falcon, in the back Wasp, in the middle row Sloth, Veterinarian and Cocoon, in the front row the uncrewed vessels and Tetrapus. I decided to not make a detailed introduction at the beginning. I will make a detailed description of each part, when it starts its own mission. I don't want to take from you the joy of thinking and guessing and the eventual surprise, when the secret reveals.
But how do all these parts fit together to a single rocket? There is one part missing on the picture, Jellyfish. I couldn't cheat Falcon and Jellyfish next to each other, without one of them getting disintegrated. So here is Jellyfish in the VAB.



It is the transfer stage with 4 Nerv engines, 4 stacks of LF and 4 stacks of LFOx tanks for spare fuel. It has also the central hub with the two main docking ports.

And here is Jellyfish with the Kerbin boosters attached. 12 Mastodon engines with asparagus staging. The benefit of the 4-way symmetry is, that I can decouple two engines each time, and it keeps symmetry, making the staging more efficient. At least for the first four stages. The final four engines will burn longer to give the necessary thrust for the ascent. Their fuel tanks are only necessary, to attach the other stages to it. Crossfeed is active everywhere, only some fuel tanks are blocked, wich I need at the first destination. Jellyfish, Falcon and Wasp have together enough tank capacity to reach the first destination for refueling. Three stacks of LF fuel tanks on Falcon are empty, because it's not necessary to fill them for the launch. The first four boosters don't have any special devices, they will detached in vertical position. The second row of boosters have a Separatron rocket and fins to support a safe decoupling in the not too thin atmosphere. The final boosters have only Separatrons, because of the lower mass, and they will detached in a nearly vacuum.



I developed every vessel independently, and I had the fear, how I would assemble them together to something, which can fly through Kerbin's atmosphere and reach orbit. It was unbelievable, but it worked instantly, I only had to attach enough engines and fuel tanks. I could say, it was skill, but you wouldn't believe it, neither I would do. It was really almost pure luck. I was prepared in mind, to spend additional weeks to modify and test my vessels, and I was so happy, that it wasn't necessary. 

And finally, here is a video of the full assembly and the launch to Kerbin orbit. I will include screenshots of the launch, so you don't have to watch the whole video, if you don't want.

On the launch pad. I switch on the fuel levels of the booster stages to know, when to stage. I activate SAS only after the rocket stopped swinging, to launch vertically, and then igniting the 12 Mastodon and 2 Vector engines.

vxOTa6H.jpegDropping the first four boosters, as their tanks empty.


Turning slightly to the east, but not more than 20°, because above it the decoupling is unsafe. I have a lot of thrust and a lot of drag, it's better to have a steep ascent through the thick atmosphere. At the decoupling of the next two boosters, switching on the Wolfhound engines, and after the next two the two Nerv engines of Falcon.


Slowly building up horizontal speed. At 1000m/s decoupling the next two boosters and starting the according two Nerv engines of Jellyfish, which aren't blocked anymore.


At 1500m/s the same procedure, and deploying the fairing. Now the Tree of Life is flying on its own power.

At 1900m/s switching off the Vector engines to increase fuel efficiency.

Switching off the Wolfhound engines too. I will need the oxidizer for the ejection burn, because 6 Nervs are not enough for 300 tons, and I will need oxidizer for the lander too.

Orbit. This was my best ascent with this rocket. I have enough fuel left. And it looks cool!! Or not?


Some thoughts to the developing process.
My first goal was to land on Tylo. This was something new for me. The only vacuum body I landed on before, was Gilly. Tylo is a bit more challenging, and it's important to progress step by step :D. My first idea was a biome hopper. I knew, it was a bad idea, but I had to make the experience. After I crashed with 700m/s into Tylo's surface at my first landing attempt, I confirmed, it's a bad idea. The next idea was, to make an all-in-one rover like Dancing Porcupine. I made a prototype around a Wolfhound engine, but it wasn't powerful enough. I tried to drive it on Tylo anyway, but it was nearly impossible to climb up slopes. I knew it already from the mission report of @king of nowhere, but again, I had to make the experience. Finally, I made a light rover, which only can drive around and carry the crew and all the science equipment (Tetrapus). But it needed a lander (Wasp).
The mass of the lander wasn't as critical, as the mass of the rover, so I could add more engines to it, to land "safely" on Tylo. Then I had the idea, if it has enough power to land on Tylo, it can lift even more mass from the other moons. Why not use it as a tanker to refuel the rest of the spaceship?
Then it came the airseaspaceplane (Falcon). At first I needed a plane, which can carry the crew and the science equipment and can fly on Laythe. Then I modified it to be able to land and takeoff on land and water. It started to be more complicated, as I wanted to reach orbit. It needed a lot of experiments until I've found the right engine combination. And then the same procedure for Jool.

For the final assembly my main goal was, to get a good mass distribution, aerodynamic stability, and the most engines usable (not blocked by other parts). To reach this, I decided to arrange falcon in-line, and screwed it by 180°, so the angle of the wings cancel out each other, and the fuel tanks are on opposite sides for a better mass distribution, and the largest wings and control surfaces are on the bottom, giving more aerodynamic stability. Jellyfish is rotated by 45°, so the Nerv engines are free too. Wasp is rotated by 90°, and with its large base (which is necessary to carry Tetrapus and for stability on the ground), the Wolfhound engines are free too.

That's all for today. Stay tuned for the next episode.


Edited by DennisB
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Episode 2 - From Kerbin to Bop   (Feb 22-25)

In this episode I go to my first destination, Bop. It took a little longer, than expected, because I had to do half of it twice. I used the time warp function of the alarm clock, and at maximum time warp the game didn't recognize the Tylo encounter, and I left Jool SOI again. So I had to reload for the first time, but I think, it wasn't really my fault. In the future, I won't use that function. I will use the alarm clock, but I will start the time warp manually, and won't use maximum speed, if I have a SOI change on my route.
I chose Bop as my first destination for several reasons. All the landings with Wasp (except on Tylo) will be refueling trips too. I will arrive to the Jool system with mostly empty tanks. To fill the tanks for the missions to the large moons, it's the best to begin with the small moons, Bop or Pol. I start with Bop, because it's more expensive in terms of dV, so it's better to go to there, when the spaceship has less mass. On the way to Bop I can use a Tylo gravity assist to reduce the inclination, and I have the tanks less than half full at the transfer to Pol. With the tanks nearly full, it's easier and cheaper to go to the large moons fron Pol than from Bop.


Just arrived in Kerbin orbit, and I'm immediately starting to mess up the environment. Ernstpold is on EVA and he's removing the nose cones of Wasp, because it won't fly in an atmosphere again. I keep the nose cones of Jellyfish, because they lead Wasp into the right position at docking.

This will be the ejection maneuver with a Mun gravity assist, to get an orbital period of 2 years around the Sun. Of course, I won't do it in one burn.

Starting the first periapsis burn (with the Nerv engines only), and avoiding the debris.

After three burns of 3min each and one of 100s, the AP reaches almost Mun SOI.

Two orbits later, when Mun is out of the way, there comes one more periapsis burn to rise AP further, to get an orbital period of almost 5 days to arrive at PE at the right time for the ejection burn. This burn takes only 50s.

Here is the plan of the ejection burn. This is really confusing, and I don't understand, why it happens. As you can see at the maneuver details, it should be a 351,7m/s prograde burn. But in the summary, there is 355,9m/s, and this value is changing pemanently, even if I don't do anything, and I can't stop it doing that. I could only hope, that my original maneuver plan is right. The estimated burn time is also wrong. There's no engine combination, which would result in a burn time of 58s. At this moment there are only the Wolfhound engines active, they would need 118s, with the Nerv engines together 83s, with the Vector engines together 30s. I suffered often from changing maneuvers in the tests, and I will suffer in the further mission too. It would be OK for me, if there would be an intended general uncertainity in the maneuver planning, but this seems to be a bug, because it doesn't happen everytime, and that's annoying. For the burn time calculation, I will use my good old calculator.

This time I'm using the Wolfhound engines too to be faster and more precise. And I've successfully crossed the minefield.

As you might think already, it didn't went well. Collision course with Mun. There's an emergency maneuver necessary to avoid it. I needed little corrections in the tests too, I think, SAS can't handle the asymmetry good enough. But this is by far worse than normal.

After all, my solar orbit wasn't right too, of course. I need normally around 200m/s to get the right Kerbin encounter to reach Jool, but now, I couldn't set up the right course to Jool, not even with a 250m/s maneuver. There is another correction burn necessary to rise AP of the solar orbit. With all these issues, I spent almost the whole 50m/s, what I've gained from the Mun gravity assist, to correct it.

The interplanetary maneuver for the Kerbin gravity assist for a Jool encounter.

The plan of the fine adjustment of the Kerbin gravity assist at the edge of Kerbin SOI to set the Jool PE to Tylo orbit. And it happened again. As I planned the maneuver, it was only 0,3m/s, but it increased on its own.

The plan was, to reduse PE from 90 to 82km, but as I arrived at Kerbin, my PE was suddenly at 542km, and now I need a 17m/s course correction.


Kerbin fly-by.

The mid-course correction to set the Tylo gravity assist for an elliptical Jool orbit and to reduce the inclination to Bop.

Releasing the relay satellites at the edge of Jool SOI.



Maneuver plan for Relay 1 for a circular polar orbit around Jool with an orbital period of 330 days.

And for Relay 2 for a transfer orbit to the opposite point of Relay 1.

Maneuver plan for a course correction to adjust AP to get a cheap Hohmann-transfer to Bop.

Relay 2 is executing its maneuver. 1h42min. Even with 4x time warp it's long. The satellites are very basic. A large relay antenna, a large probe core (with reaction wheel), two batteries, two RTGs and an ion engine. With the two RTGs it's only possible to run the ion engine at 20% power. But it's OK, I don't want to move the satellites around, once they've reached their orbits.

The circularization maneuver in 375 days.

The burn time of Relay 1 is even longer.


As I arrived at the point of the course correction, it was wrong again, and I need a new one. And the second maneuver is 20m/s larger, than before, but from here I took extra attention to time warping. At the first attempt, I passed Tylo, without a gravity assist, and I had to reload. Unfortunately, my last save was after the ejection from Kerbin SOI for the first time, and I had to redo everything since then (interplanetary maneuver, Kerbin fly-by, correction maneuvers, relay satellites).


WmBYvKN.jpegPassing Tylo for the first time.

And finally, there is a Bop encounter. I'm arriving in an almost polar orbit, so I can reduce AP already below 325km to scan the surface. I don't need a huge inclination change. Earlier I had an accidental Bop encounter during the maneuver planning. I looked, just for fun, it would've take 1750m/s to capture at Bop. This way I needed just a little more than 2000m/s for the entire trip from LKO to Bop orbit.

Capture burn at Bop.

In orbit.


There is still enough fuel for 90s burn with the Wolfhound engines and 500s wit the Nerv engines, or 760s with the Nerv engines alone. This is approximately 1400m/s. I had here a very large safety margin, because I'm still not really confident with the maneuvers. I promise, the safety margins for Wasp and Falcon will be much smaller.


Edited by DennisB
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  • 2 weeks later...
Posted (edited)

Episode 3 - Bop, and more vessel introductions    (Feb 28-Mar 03, Mission day 1-58)

This episode will cover the entire science collection on and around Bop, the drive on the surface, some refueling, more vessel introductions, and probably the first highlight of the mission. I don't know, if the intro or the launch from Kerbin already was a highlight for you, but this one will be something different. I hope, it won't be too confusing, but I will present the timeline as it happened. That means, I will jump between the vessels and missions, like I did it in the game, so you can get an impression, how everything happens for me while playing. This episode is really long (probably the longest), because I give more detailed descriptions of the vessels, which I didn't do in the first episode, to keep the tension, and I won't go into the details as much in the future episodes at the repeating processes.

Part 1


At first, releasing Sloth. Being already in a polar orbit between 25 and 325km, it can perform the resource scan immediately.


It looks very good. There is enough ore almost everywhere. This gives flexibility at choosing the landing spots.


Introduction of Sloth - Crew: Reibrecht (pilot), Meidunja (scientist)


Sloth is designed for collecting the space science. It will do it all, except the low space science at Jool. It has every necessary science instrument: science jr., mystery goo, thermometer, barometer, magnetometer, infrared telescope and 4 gravimeters. In space, only the gravimeter is biome sensitive, so that's the only one, of which I need four pieces to collect each science data four times. Because all the moons have at least four biomes, the other experiments will execute at least four times (over each biome), over Jool, I will just do everything four times. I have four science containers to store the science reports. The science jr., the mystery goo and the infrared telescope give marginally low science points for the 5th copy of the science report, which I can store in the command pod. Unfortunately, I have to collect those science reports with a kerbal on EVA, but that seems to be impossible for the infrared telescope. The infrared telescope is also the science experiment, which doesn't work via action group. Inside the structural tube, where the docking port is, is a monopropelant tank. I have RCS thrusters installed, but I realized only at the end of the test mission, that the Mk2 command pod doesn't have monopropelant, so I couldn't dock. There are two ion engines for an adequate thrust, but with the two RTGs and three batteries, they can provide full thrust only for 200s, which is 125m/s at the start, if I need more, I have to reduce the throttle.



Part 2


Immediately starting to collect science over Bop. High over Slopes.

The process of the science collection:
on EVA - EVA report (if necessary) - EVA experiment (if necessary) - back on board
starting the science instruments via action group - collecting the science reports into the science container
on EVA - restoring the science jr. - restoring the mystesy goo - back on board
On the 5th occasion, after I restore an instrument, I run the experiment again, collect the science report and restore the instrument again.

Meidunja with the EVA experiment. I won't include that screenshot in the future. She goes on EVA everytime to make EVA reports and to restore the science jr. and the mystery goo.

High over Peaks.

Maneuver plan for the mothership to circularize the orbit.

High over Poles.

High over Ridges.

High over Valley. I've got all biomes in the first orbit.

Maneuver plan for Sloth to get into low orbit. At Bop it's below 25km, which is just a little higher, than the highest elevation of the moon.

Low over Slopes.

Low over Peaks.

After the circularization burn, unblocking the fuel tanks on the bottom corners of Wasp. I need only these four fuel tanks full to land on Bop.

And transferring the fuel from all the other fuel tanks into Falcon's fuel tanks. As you can imagine, the fuel transfers need a very long time, because I have around 140 fuel tanks.

After the fuel transfer, Wasp is on the way with Tetrapus to the surface.


Introduction of Wasp - Crew: Valentina (pilot), Ernstpold (engineer)


Wasp is designed for landing on the airless moons, transport Tetrapus, mine and refine fuel for itself and for the other vessels. It's the only member of the Tree of Life, which gets its power from fuel cells. Mining and refining fuel needs too much energy to provide it with RTGs, and solar panels are inefficient that far from the Sun. It has a large convert-o-tron onboard, because the small one is too inefficient to provide enough fuel for the fuel cells to keep the whole process sustainable. With the large one, and an engineer onboard, I can refuel even at low ore concentration. On Wasp and Tetrapus I use the spherical command pods, becuase they have a lower mass, than the conical ones, but probably more important, they have a smaller base, and fit better to the adjoining parts.

Wasp has two Wolfhound engines for high thrust and efficiency. It has two drills and cooling panels only for the symmetry, one of each would do the job too. There are extra LF tanks to refuel the LF tanks of Falcon and Jellyfish. The rubber pads on the bottom are there, because landing on Tylo can be rough. I did the drop test (I can't remember if on Kerbin or on Tylo), and with the rubber pads I could improve the vertical impact tolerance from 13 to 16m/s.


Part 3


The course to the landing spot. I want to land close to the north pole on a nearly flat terrain for several reasons. It's obvious, why a flat terrain is better, but this one has high ore concentration, all biomes in the proximity, and it is in the northern hemisphere. The last one is important, because the relay satellites haven't spread out yet, and both of them are over the northern hemisphere.

While waiting for the maneuver of Wasp, collecting more science with Sloth. Low over Poles.

Adeldorstina is on EVA to put out a probe core. I have several probe cores in the inventory. The plan was, to collect as much science with vessel recovery as possible with a resonable effort. The vessel recovery points are given for the most valulable situation of a command module. But it's a little tricky, because there are also fraction points for multiple copies, but the decision, which situation counts, is based on the max value. I added the necessary number of probe cores after the test mission into a container, and was confident to fulfill the plan. But now I know, I shouldn't assume, that things will work as expected, whithout testing them. The problem is, if I put a probe core out of the inventory, I can't fix it on the vessel. I will try to do my best to get the recovery points, but I will only see at the end of the mission, if I'm successful or not.

On the way to the surface.




Adeldorstina and Kaydre are on EVA to put a rubber pad onto the bottom docking port of Tetrapus as a protection, and to deploy the surface experiments. There's the bug again with the phantom jet packs, I had issues with on my Eve mission too. I have to keep in mind, where the jet packs are in real, and don't believe the inventory windows.


I have all experiments for vacuum bodies. The rules of the challenge say, that only recovered science count for the final score, so I have to prevent the experiments from transmitting the science to Kerbin. The first thing I can do is, to not install a communication unit. I didn't even bring one to the mission. But this is not enough. To get connection to Kerbin to use KerbNet for navigation, I have to use the largest relay antenna on the relay satellites. But the control unit of the surface experiments can connect to them from a quite large distance. That's the reason, why I put the relay satellites into a 700Mm orbit. Because of this, I have to use on my vessels a strong direct antenna to use KerbNet, which is too fragile to use it in an atmosphere, so on Laythe I have to navigate oldschool.

Trying to put the probe core into a landed state to get the recovery points for landed on Bop.


Starting the fuel production.

Now we are coming to the highlight of the episode, and to the other uncrewed vessel. I don't know, who guessed it right.

It's a projectile for the grand slam experiment. Here is the uncut video, the screenshots with explanation will follow.

It's basically a fuel tank with engines. I used radial engines, because at the bottom, there were the Kerbin boosters attached at the launch. With two Cub engines it's ridicuclously overpowered, but it's OK. It has a large probe core with built-in reaction wheel, an antenna and a battery, which can provide energy for the short flight.

The maneuver plan for the approach.

Adjusting the trajectory to the target.

Getting up to speed, after the distance to the target is low enough and the trajectory is good.


REPAsnH.jpegImpact. The impact energy is 1778% of the required amount, and there are no reductions because of the distance (it was close enough) and the experiment configuration (it was deployed by a level 5 scientist).

h6kG5Rw.jpegKaydre is recovering the experiment.




Introduction of Tetrapus - Crew: Hemmens (pilot), Adeldorstina (engineer), Kaydre (scientist)


Tetrapus is designed for driving around on the airless moons and collecting all the science. It has all the necessary science instruments: science jr., mystery goo, thermometer, barometer, gravimeter, seismometer and a scanner arm. Because I run the science experiments stationary, one of each instrument is enough to save mass. Overall I tried to keep the mass of the vessel low to avoid trouble on the slopes, and to reduce the payload of Wasp.


It has four medium reaction wheels for stability and eight RTGs for power supply. It has a hydraulic suspension to adjust the stiffness and the ground clearance.


It wasn't easy to place the different instruments to get all wheels equally spaced and the mass balanced.

I didn't plan it, but it was necessary to add four telescope arms. I could rise Tetrapus with the suspension only to dock it to Wasp. Unfortunately, there is a bug, which cause exploding wheels if they touch the ground at the moment of docking. On Pol and Bop that's no problem, because in the low gravity, the force of the docking port is enough to suck Tetrapus off the gound, but on Vall and Tylo I need the telescope arms. An additional benefit is, if I use the telescope arms, when I use the scanner arm, I don't have the issue of the moving vessel.

Probably the most important thing, the wheel and suspension settings. I didn't spend too much time to adjust it, because it worked almost instantly. I played in the past sim racing games a lot. I know, how much time it can take to fine tune the setup, and I didn't want to spend that much time. For a good handling, I set the friction on the rear much higher than on the front, it helps also to climb up steep slopes, and I set the traction control in the opposite way. The brakes are of course stronger on the front wheels. I set the steering lock lower and the backforce higher on the rear, than on the front, together with the higher friction level on the back, it should help to stabilize the vessel, when it doesn't land straight after a jump. On the wheels I have the dampers always at maximum, I adjust the damper level on the suspension, together with the ground clearance. With a higher ground clearance, it's less likely, that I smash the bottom to the ground (I have rubber pads to protect the science containers and the docking port), but it makes the vessel less stable at high speed. A lower damper setting gives more stability at larger gravity, but it increases the load on the wheels, so they break more likely, and at low gravity the vessel jumps more, there is a higher damper setting better.


Part 4


Tetrapus is starting its mission on Bop.



The process of the science collection:
on EVA - EVA report - EVA experiment (on first occasion) - surface sample - back on board
starting the science instruments via action group - collecting the science reports into the science container - on EVA - restoring the science jr. - surface sample - restoring the mystery goo - back on board --- this three times
starting the science instruments via action group - collecting the science reports into the science container - on EVA - restoring the science jr. - starting the science jr. - collecting the data - restoring the science jr. - surface sample - restoring the mystery goo - starting the mystery goo - collecting the data - restoring the mystery goo - back on board

Kaydre with the EVA experiment.

Scanning the gravel pile.


And the necessary flag to mark the route.

Jumping/flying over the surface of Bop. At larger jumps on the low gravity moons I have the time to adjust the orientation of Tetrapus for an ideal landing, and if the jump is even larger, I push out the suspension to the maximum to absorb more energy at the landing.

Peaks. My plan was, to drive only in daylight, because I don't have any lights, but for some reasons I ignored the plan, though I know, it's slower if I drive in darkness. But, Bop is dark even at daylight. :D


Starting the long and steep descent to the valley. It goes 7000m downhill.



I can't go straight downhill, because it's too steep.



Valley, the final biome. It wasn't a long trip, thanks to the good landing spot. And now, waiting for the taxi to orbit.



Now I have time to come back to Sloth. Low over Ridges. This biome is really narrow, I have just enough time to do the experiments and the EVA report, but I need too long to restore the experiments, so I have to wait another orbit to get the final biome.

Here I noticed, that my orbit is much lower, than it was at the beginning, and both AP and PE decreasing by 1m every 20-30s, like there would be an atmosphere. It's good, that I didn't circumnavigate Bop, in the meantime Sloth could have crashed into the surface. But now there is a little prograde burn necessary.

Low over Valley. The final biome.

Pol is on the wrong side of its orbit, but Sloth doesn't have time pressure. That's the reason for its name.

Rising the orbit further to get out of the danger zone.


Wasp still needs a little to fill the LF tanks.

In the meantime I send the next probe core to hopefully improve the recovery points.


Introduction of Veterinarian - Crew: Jaseida (pilot), Bill (engineer)


Veterinarian is designed as a support and passenger ship, to move heavy parts around and ferry the crew between vessels. But during the test mission I extended its tasks to optimize the mission overall. Veterinarian is a very similar construction to Sloth. It has the same engine and power unit, but instead the whole bunch of science experiments, it has only a magnetometer and two crew containers. I added the magnetometer, because Veterinarian will support Falcon on its mission, and it has only the atmospheric experiments onboard. The magnetometer is the only one, which is necessary in addition to them, to complete low space science. Veterinarian will go to Jool, and with a magnetometer onboard, Sloth doesn't have to go to a low Jool orbit. The other additional mission is, to bring the probe cores to a suborbital trajectory for more recovery points. Sloth has the same maneuvering capabilities, but it performs its mission on its own, and has no access to the main ship and the additional probe cores.


Part 5


Getting suborbital.

And again, I try my best to get the task done. I still can't mount the probe core on the vessel, so I just put it into space.


And now, back to home.

The first docking maneuver of the mission. Many more will follow. During the test mission I really improved my docking skills.


Putting the used probe core into a crew module of Cocoon, so I know, which ones are fresh and which ones are used.


Wasp is full. It needed only one day for it. But the surface experiments need many more days. Until then I shut down everything, to not use all the fuel for the fuel cells.

Planning the transfer to Pol for Sloth. Because it has limited burn time, I will use it with the minimal Oberth-effect to adjust the inclination (I'm in a polar orbit), and escape into a nearly circular orbit around Jool, from where I can do a transfer burn to Pol, whenever it's the cheapest.

The descending node is less than 3h away, so I will rise the AP immediately to set the orbital period right to do the escape burn one orbit later.

The final ejection burn. 3min 19s burn time, it's exactly the maximum, what Sloth can do on full throttle.



High over Jool.

The maneuver for the transfer to Pol in 37 days.


And the plan of the capture burn into a polar orbit. All within the burn time limit.


After 53 days, the surface experiments have finished.

Ernstpold is on the way to recover them.

After I added the rubber pads to the bottom of the fuel tanks, the ladder is too short. It needs a jump to catch it. Carrying the surface experiments doesn't allow to carry a jet pack too.


The mothership is already too far ahead to catch up to it, but I start though.

In Bop's gravity, Wasp has no issues to lift off with 150t.



Matching the inclination.

And rendezvous on the next orbit.


Without Tetrapus, I have to dock head first, but it's OK, because after I've dumped the fuel, I will go back to the surface to meet Tetrapus and bring another load of fuel.





I decided to fill the ore tanks too. After docking, there are many RTGs and batteries available to run the convert-o-tron with some recharging breaks, so I don't use fuel for the fuel cells. Here I refine liquid fuel, because on the test mission I made the experience, that I get the LFOx tanks faster full than the LF tanks.

The fuel transfer again... You know, what I mean. :confused:

Two probe cores done, six remaining.

Ready to go, again with only the bottom corner tanks filled.

Planning the course to Tetrapus.


Here you can see the 7000m slope in full extent.

Landing in the valley.


Starting the fuel processing.

After 54 days waiting for the taxi, Tetrapus has to do a final 2km journey, but this time on flat ground.

To dock, Tetrapus has to drive backwards under the docking port, because the scanner arm can't go through underneath the tanks.



After one more day, the tanks are full again.

Here you can see the entire tour of Tetrapus on Bop.

On the way to orbit.

Adeldorstina is on EVA to remove the protector from the docking port.


The inclination change with a direct rendezvous.

This time, docking in the right orientation.



And the same procedure as before. :D

The first moon completed. Falcon's Jool stage is refueled, and Jellyfish is half full. Ready to start to the next destination.


If my calculation is right, I collected 99,13% of the available science at Bop, if I get the recovery points for the two probe cores, or 98,17%, if not.


Edited by DennisB
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8 hours ago, king of nowhere said:

i suggest you increase background light in the options, most of those screenshots are just a black screen

That's interesting, because on my laptop, most of the pictures look fine, and I have the brightness setting of my screen on minimum. I looked at the pictures on the computer in the office, and on that monitor, with a much brighter screen setting, the dark parts of the pictures looked much darker, than on my laptop. I think, the contrast there is simply too high.

I use the same settings always. Were my screenshots from the VAB, Kerbin, Gilly and Eve dark too? I think, Bop is really dark, even at daylight.

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Vab pictures are fine.. there is not enough ambient light for the enviroment you were in.


There are some mods that increase ambient in various scenes settings.

I had this problem.. when the sun is occluded you can't see for excrements and cranking the brightness on my screen produced raging headaches.




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4 hours ago, DennisB said:

That's interesting, because on my laptop, most of the pictures look fine, and I have the brightness setting of my screen on minimum. I looked at the pictures on the computer in the office, and on that monitor, with a much brighter screen setting, the dark parts of the pictures looked much darker, than on my laptop. I think, the contrast there is simply too high.

I use the same settings always. Were my screenshots from the VAB, Kerbin, Gilly and Eve dark too? I think, Bop is really dark, even at daylight.

it's not screen brightness, it's game brightness


turning it up is useful for seeing by night. and for taking screenshots by night that can be seen

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Yes, I know that setting. I read your posts and I know, you use it. Back then, I didn't understand, why it was important for you to turn the night into day. I found your screenshots with the original light settings good too. I simply didn't know, how much worse dark pictures look on other screens different from mine.

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Episode 4 - More space science    (Mar 10-19, Mission day 58-118)

I planned for this episode to land on Pol and collect all the science there, but because of the bad constellation of the moons, it has to wait. But the mission of Sloth, collecting space science, made good progress, it will fill this episode.

Overview of the situation


Relay 1 completed half of its orbit, Relay 2 has 183 days until its circularization burn. When I land on Pol, the satellites will spread out enough to have connection on the southern hemisphere too. This gives more flexibility at choosing the landing spot.

The Tree of Life is still orbiting Bop, ready for the transfer to Pol. Sloth will encounter Pol in one day.

The constellation of Bop and Pol is really bad. I want to perform the same maneuver with the Tree of Life to go to Pol, like I did it with Sloth in the last episode. The ascending node is almost a half orbit away, but it's close to the periapsis of Bop, which would make the inclination change more expensive. Because Pol is in such a bad position, it's better to wait almost a whole orbit, and escape at the descending node. That way I will arrive at Pol at the same time, but much cheaper.


Around Pol


Meanwhile, my planned capture burn "magically" moved to somewhere outside of Pol SOI. To make it even worse, if I use time warp, my encounter disappears too, and the alarm moves 30 days further into the future. :mad:


So I need a new capture maneuver.

Starting to collect science already during the approach to Pol. High over Midlands.

High over Highlands.

High over Lowlands.

High over Poles.

Established circular orbit to perform the resource scan.


The ore distribution is much worse, than on Bop. There are many places with high concentration, but half of the surface has no ore. I have to keep this in mind, when I land. Luckily, landing on Pol is very easy, it shouldn't be a problem.

Lowering the orbit further to get low space science. I realized later, that low space at Pol is below 22km. 25km was the limit on Bop and the limit of the resource scanner.

Low over Midlands.

Low over Lowlands.

Low over Highlands.

Low over Poles. Got all biomes.

After only 2,5 hours in Pol orbit, I'm ready to leave. I can do it every time, because the Oberth-effect of Pol is negligible, and being in Jool orbit will make it easier to plan the next maneuver. I don't care about the inclination of 2,8°, because I want to enter into a polar orbit again. The lower inclination makes Pol to a much better starting point to reach the inner moons.




Around Laythe


Maneuver plan to reach Laythe with a Tylo gravity assist.

After I had so much trouble with maneuver plans in far future, I waited this time too long, until I entered Tylo SOI, to adjust my trajectory to get a nearly polar orbit around Laythe. It was more expensive, than necessary. Around Laythe I don't need a real polar orbit, because Falcon doesn't have mining equipment, I don't need a resource scan. My inclination just have to be high enough to pass over the poles.

Correction burn at Tylo fly-by.

A very cheap capture at Laythe. Sloth could do it with one burn with full thrust even without aerobraking. I will take a small dip into the atmosphere though. Not too much, because Sloth isn't designed to withstand entry heating, but this will give it the recovery points for atmospheric flight at Laythe.

Maneuver plan of the mothership to escape Bop and match the inclination to Pol.

After waiting over 20 days for the maneuver, while Sloth spent most of the time with the transfer through space, the escape maneuver will happen almost at the same time as the Laythe capture.

Like at Pol, I'm starting the science collection already during the approach. High over Shores.

High over Sagen Sea.

High over Shallows.

Finally, it's time for the Tree of Life to leave Bop.


Sloth is coming closer to capture. High over Poles.

Prepared for the atmosphere. I closed the cargo bay and retracted the antenna and the scanner.


Low over Sagen Sea.

High over Degrasse Sea.

Rising PE to 150km, and on each orbit I will reduce PE with a 2min retrograde burn, so I can collect low and high space science on each orbit. Reducing orbital speed on the lower part of the orbit is useful to collect gravimetry scan and EVA report of the same biome in a single passage.

Maneuver plan of the mothership for the transfer to Pol.

Low over Dunes.

Low over Shores.

Low over Shallows.

Low over Degrasse Sea.

High over Dunes.

Low over Poles.

Establishing the final 190x210km orbit.


High over Peaks.

High over Crescent Bay.

Low over Peaks.

Low over Crater Bay. Most of the science reports collected within 2 days.

One day later, high over Crater Bay.

Another day later, low over Crater Island.

There are only two biomes left, but one in high and one in low space. I missed them several times. To rise my chance for a passage, I spent 250m/s to reduce the inclination of the orbit. 11 days later, low over Crescent Bay.

Now I can rise the PE over 200km, to have on both sides of the orbit a chance to get the final biome.

But no luck. Only after 13 days I had two close passages, but my thrust level is too low to do an effective course correction that close to the target.


The Tree of Life at its maneuver to set up the Pol encounter.

And the planned capture in 16 days.

Back to Sloth with a new idea. After I had two consecutive close passages, let's try to keep on with them and set up some kind of resonant orbit. The closest one was 1/20 of Laythe's period. For that, I only have to reduce my orbital period by 20 seconds, and I will still stay in high space. So I will have the possibility to tweak the orbit further with normal burns close to the poles.

But the latter one isn't necessary, because there is a passage already on the next occasion. High over Crater Island, the final biome of Laythe. I needed over 30 days and 240 orbits to get them all. I can only hope, that Tylo will be better.

The maneuver plan for the transfer to Vall. Starting from an almost polar orbit makes it a little difficult to get a good and cheap transfer. I have to wait with the ejection to the moment, when my orbit is well aligned with Laythe's orbit, to get the highest possible prograde component. Because I have limited burn time and low thrust, I have to split the burn into several parts, and I don't have enough time until the next ejection window, so I have to take the one after it. And luckily, I have directly an encounter with Vall. That's good, because as you can see, my orbit around Jool will have a significant inclination, which would make it more difficult/expensive to modify it for a future encounter. Another option would be, to rise my AP and rotate my orbit around Laythe to equatorial, but then I would have already a longer orbital period, and it would make it more difficult to get the right ejection window, and most likely, it would cost more dV overall.

The maximum available burn with full thrust at the moment. I will need three of them to rise AP.

And a small one at the end to adjust the timing of the ejection burn. There is a glitch in the graphics, the projected orbit isn't visible, only the AP. I will have this later too.

After two orbits, the 110m/s ejection burn for a Vall encounter, with Vall and Tylo in the background. I've increased the ambient light setting. I hope, the pictures from now on will look better.



Around Vall


A course correction after leaving Laythe SOI to get a nice polar obit around Vall with a low PE.

Now, we have a problem. I was so happy to get a direct transfer to Vall, that I didn't consider, how much normal and radial components my encounter will have. I can burn only 130m/s with full thrust, and persistent with only 10% thrust. I messed it up, but I have a lot of fuel. I don't want to reload in such a case. There are several options. I can make more expensive maneuvers to get a cheaper capture. I can tweak my trajectory to set up a second encounter, to do the capture in two parts. Probably I would choose this option, if I would be in an equatorial orbit, but with that inclination I could end up in a much worse situation. I choose the third option. I try to do the capture burn manually, and use the ion engines in a way, like they are used in real life. It will be tight, because Vall SOI isn't really large.

Entering Vall SOI and starting the capture burn immediately with 10% thrust, to keep the batteries full for a full 130m/s retrograde burn at PE. The goal is, to adjust the radial out component of the retrograde burn, to keep PE at a safe altitude. With the last course correction I could reduce the capture to 290m/s. Let's see, what happens. There are 41 minutes left until PE.

Using time warp, to get it done faster.




4 minutes until PE. Now burning retrograde to increase efficiency, because that close to PE, it won't drop into dangerous regions anymore, and I want to get full benefit of the Oberth-effect.

Full thrust close to PE.

The batteries are empty. Burning further retrograde with 10% thrust. It's no problem anymore, if PE drops below zero, I can correct it later. AP at 16,8Mm, it has to go below 2,1Mm, there's still a lot to do. From this point, the maneuver node doesn't make sense anymore.

Capture completed at around 750km altitude :cool:, and there's only a 10m/s burn necessary, to rise PE to a safe level. The whole maneuver took 73 minutes and with the final burn together 360m/s.

Immediately starting with science collection. High over Mountains.

High over Midlands.

High over Poles.

Like at Laythe, I will lower AP with 2min burns at PE.

High over Highlands.

High over Southern Basin.

High over Northwest Basin.

Low over Highlands. Some biomes are really narrow. In this case (and some others too), I had to collect the EVA report later, but I've got them all.

Low over Midlands.

Now in the right orbit (between 30 and 1500km) I can perform the resource scan. This looks really good. I want to land at the equator, and there is ore everywhere.

High over Lowlands.

High over Southern Valley.

Low over Northwest Basin.

Low over Lowlands.

Low over Poles.

Low over Northeast Basin.

Low over Mountains.

There is one biome left in high space in the northern hemisphere and two biomes in low space in the southern hemisphere. I have to change the orbit, I need AP at the north pole and PE at the south pole. Luckily, the remaining biomes are large enough, so I will get them as soon as Vall rotates to the right position.


High over Northeast Basin.

Low over Southern Valley.

Low over Southern Basin, the final biome.

The maneuver plan at the next ejection window for a transfer orbit to Tylo.

Again, splitting the burn into a full burn to rise AP.

A smaller one to rise AP further, and to adjust the timing of the ejection burn.

The ejection burn.


Maneuver plan for the Tylo encounter.


In the next episode, I will really drive around on the surface of Pol, if we can call that driving :D.

Edited by DennisB
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Episode 5 - Pol and more space science    (Mar 21-23, Mission Day 118-182)

In this episode I will land on Pol to collect all the surface science, and I will also finish the mission of Sloth.

Overview of the situation


Relay 2 still has 123 days until its circularization burn, but as you can see, the constellation looks already very good.

Sloth is just about leaving Vall, in four days it will have a maneuver to get a Tylo encounter. The Tree of Life will arrive at Pol in five days.


Around Tylo - Part 1


After the maneuver, the predicted Tylo orbit is far away from a polar orbit. Thanks to the large SOI of Tylo, it's quite cheap to turn it into a polar orbit with some normal burns at apoapsis.



Pol - Part 1


Arriving at Pol.

Taking a fresh probe core into the cargo bay of Wasp, and checking the fuel. Again, only the four bottom tanks on the corners are full. In theory, I can land on Pol with only two tanks of fuel, but I have enough fuel available.

I will land at the south pole, because there is ore in almost every direction around it.

Wasp is on the way to the surface.





Deploying the surface experiments.

And starting the fuel production.

The mothership is in a good position. It's time to launch the next projectile.



This time I will go straight down, to get the impact position more precise. I have to reach the surface, before running out of battery power.




Almost perfect shot. 2655% energy, but only 68% of it will count, because of the distance (and I thought, 1km would be close enough, on Bop I was further away), but that means again, full science points.


"Landing" the probe core for potential recovery points.

Starting the science collection with Tetrapus at the Poles biome.


The plan is, to climb up from the valley in the center of the image onto the hill further back, and then to look for the other biomes.

Setting the suspension height to 0,60m, the highest value I use.

After a very short drive, I've got a stone, and as you can see, I've reached already the Lowlands.




"Driving" on Pol. The biomes are so close to each other, I didn't even reach cruising speed.


The scenery at the Highlands biome. The landing site is still visible.



Here I noticed, that I forgot to collect the EVA report at the last biome. Kaydre can make a little tour with his jet pack. I think, I'm using a jet pack here for the first time on the surface. Carrying the surface experiments doesn't allow to use it.

Midlands, the final biome. It took just a little over an hour to get them all. I spent more time with going in and out to collect surface samples and to restore the science experiments, than with driving.



Veterinarian is on the way to get the next probe core into a suborbital trajectory.



And back again.




Wasp is refueled, and it's going into hibernation, until the surface experiments get finished.


Around Tylo - Part 2


I came back to Sloth just at the right time to see, that the maneuver is on the wrong side of the orbit, just before the ejection point.

The new capture maneuver.

Starting the science collection. High over Lowlands.

High over Midlands.

High over Gagarin Crater.

High over Highlands.

Low over Lowlands.

Low over Midlands.

Low over Highlands.

High over Galileio Crater.

High over Minor Craters.

Turning the orbit. The burn was larger, than the batteries can supply, but the orbital speed is so low at that altitude, that I could continue the burn with low thrust, until I've got a polar orbit.

Starting with full 200s burns at every PE to lower AP.

Low over Minor Craters. This biome is too small, I have to collect the EVA report next time.

Low over Grissom Crater.

High over Mara.

Decoupling the first xenon tank.

After three periapsis burns I can run the resource scan.

This looks really bad. I wanted to land on the equator on the lowlands next to the large craters, but there are only small patches with ore. And Tylo is the moon, where it's the most difficult to land at a specific place. While orbiting Tylo, I looked for the topography, but the difference of the altitude at specific points, which were significant almost everywhere, even in the lowlands, don't tell me enough about the slopes. Maybe I have to land in one of the craters. That will be interesting.

Decoupling the scanner and the infrared telescope. They've done their job, and I've got almost 1000m/s additional dV.

Now I can get 155m/s in one burn with full thrust.

Establishing the final 225x275km orbit. Luckily, Tylo rotates slowly, so I can get all biomes during one rotation. It's better, than Laythe.


Low over Galileio Crater.

Low over Mara.

Low over Gagarin Crater.

Low over Tycho Crater. The last one in low space. Now I can rise the orbit to get it in high space too.


High over Tycho Crater.

High over Grissom Crater. The final biome.

The mission of Sloth is completed. Ther are 201 individual science reports, 143 2nd, 3rd and 4th copies, and 22 5th copies. The second number should be 147. Something is missing. I hope, it's the magnetometer, because it behaves strange, and it gives full points already for the first report.

Rising AP with 200s burns at PE, then turning the orbit to equatorial.

The final orbit after 1000m/s spent. Sloth will wait here until the others arrive here too.

It's got clear during the test mission, that Sloth will finish much earlier, than the rest. It has a lot of dV in the tank, so I thought about an additional mission, visiting an asteroid. I was ready, to bring a second telescope to the mission, to put it into a solar orbit right outside of Jool SOI to detect asteroids, which cross Jool SOI. I cheated a telescope there in the test mission, but within a year, it didn't find anything, so I dropped the idea. There is still a lot of fuel onboard though. The main mission of Sloth is finished, but I will probably need that fuel to go home. The Tree of Life doesn't have dedicated fuel for the return to Kerbin (except a little, to slow down in the atmosphere enough to not burn up). It will rely completely on the fuel, remaining after each vessel has completed its mission.

Pol - Part 2


Meanwhile on Pol, the surface experiments are far away from finishing. There's nothing else to do, than time warp.

39 days later, they've finished.

It's tricky to grab a ladder while jumping in low gravity. In the test mission I had several accidents, where I destroyed the antenna and the cooling panels in this situation. One of the reasons, why I retract everything. It's funny, how kerbals can put the surface experiment into the cargo bay, while flying.

This should be the direction after the launch.


Setting up a rendezvous.




I brought up full ore tanks again to refine liquid fuel on board.

Placing the probe core into the crew cabin.

At the fuel transfer I was really surprised, that I already have too much oxidizer, and the LF tanks are almost full too. Here you can see the fuel level after Wasp undocked. Was I that much more efficient, than in the test mission? At the second landing on Pol I won't need to refill the tanks completely, and probably it will change the fuel situation at Vall too, but I will see it, when I'm there. Generally, there will be a lot of fuel calculation during the further mission.

Releasing the left-over oxidizer, it would be a ballast during the landing. I was surprised, how much thrust this process generates.

Without ballast, on the way to pick up Tetrapus.




Starting the fuel production.

Tetrapus has only 1km to go.

The necessary flag at the launch site.

Refueling completed. I have only 1/3 of the oxidizer capacity filled. That's the amount, what I need to rendezvous with the mothership and to land later on Vall. I filled the liquid fuel to the maximum, because I will use a lot of it for the transfer to the inner moons.

Launching to the same direction, as the last time, but somehow, my trajectory was messed up. I think, it's the lack of experience. That's why I feel uncomfortable about the Tylo landing, if I have to use an inclined orbit (if I can't land on the equator), because there, this would be very expensive.


But now, I have to correct it.


Back again.

The route on Pol. That was an extremely short tour. If my calculation is right, I collected 99% of the available science at Pol, if I get the recovery points for the two probe cores, or 97,89%, if not.

The Tree of Life is ready for the next adventure. With a lot of fuel, it has a mass of 509,5t. Not bad. That's the highest level during the mission, except the launch on Kerbin. I hope, the last two episodes weren't too boring. There wasn't much excitement, except the Vall capture. But the next episode will be completely different.


Edited by DennisB
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Posted (edited)

Episode 6 - The Grand Separation and the journey to the inner moons    (Mar 24-25, Mission Day 182-238)

In this episode the Tree of Life will perform a major transformation and split up into different parts.


Relay 2 still has 59 days until its circularization burn.
Sloth is waiting in an elliptical orbit around Tylo. The Tree of Like is ready to leave Pol.


After 7 days, the orbit is aligned to Pol's orbit to escape in retrograde direction.



Waiting with the plane change until the descending node. On the ascending node it would cost 50m/s more.

Maneuver plan for a Laythe encounter with a Tylo gravity assist.

With such a high mass, it takes 5min with the Nerv engines.

Making sure, that all of the 69 fuel tanks on Falcon are full. 22 were not, so another fuel transfer is necessary :rolleyes:. Falcon will leave the Tree of Life now, and it won't get fuel anymore.

Here is the full uncut video of the Grand Separation. Screenshots will follow, as usual.


After cutting the struts and undocking, the upper part of the ship is slowly gliding away, releasing Falcon.

Veterinarian is on the way to dock with Cocoon.


After both of them are undocked, Bill is on EVA, and he's moving the docking port from Falcon to Veterinarian. I don't want that extra mass and drag in the atmosphere.


Reconfiguring the aerodynamics of Cocoon for atmospheric flight.

Docking to the main hub. I could do it much better, but I forgot to install the additional RCS thrusters of Veterinarian on Cocoon.


Transferring monopropelant from Wasp to Veterinarian.

Back to Falcon.


Bill is on EVA again. Here I had the problem of tumbling again. I had it already on my Eve mission. Later, I discovered, that time warp stops it, but not now. I was really close to reload, because I couldn't get Bill under control. But luckily it stopped as I switched to construction mode. You can see the tumbling between 46:57-49:39 in the video. What's the reason for it? Is it the size of the ships? In the Sloth mission I did EVA 50 times without this problem.
The final task is, to get Falcon aerodynamic for atmospheric flight. At first, removing the docking port, and then moving the nose of one of the fuel tanks, which won't fly in an atmosphere again, to the nose of the plane. The attachment is a bit difficult, probably because of the chutes. I don't know, why it works from some angle and not from others. My first design had a simple nose cone, but it blew up in Jool's atmosphere. This design is better, I don't know, why.



Course correction for Falcon to get the Laythe encounter again. It was quite difficult to get the encounter speed low enough. I don't want to spend more than 250m/s for the capture, because that's the amount of fuel, which I don't want to bring down to Laythe and which I can't dump in the Jool stage. If I use more fuel, then I have to do more aerobraking at Jool.

The course correction for the Tree of Life. It will perform a close fly-by at Tylo to get a periapsis close to Vall's orbit.

Another course correction for Falcon before the Tylo encounter.

Maneuver plan for the Tree of Life after the Tylo fly-by, to set up a Vall encounter on the second orbit with a low encounter speed.

Falcon at the correction burn close to Tylo.

The maneuver was successful. The Laythe capture will be less than 100m/s.

The Tree of Life at Tylo. Maneuvering with 220t is much better than with 500t, even with two engines less.


This maneuver wasn't successful, I need a little correction to get a Vall encounter.

Capture burn at Laythe. I'm using the Vector engines again, because I have enough fuel for them, and I have to use the oxidizer too. In this configuration, Falcon is unstable, I can't use more than half thrust. Because of the problems at Jool on the test mission, I increased the gimbal range of the Vector engines from 10 to 25%, which doesn't help in this case.

A little correction to get an equatorial orbit.

I delayed the Laythe landing a little, because the Tree of Life had its correction burn in the near future, and I did't want to get disturbed during the landing process. After the course correction, it's 4 days until the capture burn. That's enough time to land on Laythe.

Before the next separation, I'm transferring as much liquid fuel as I can into the Jool stage. Every drop will give more dV to slow down, and I need less aerobraking. I have 2x3 stacks of fuel tanks on the bottom of the Jool stage. In theory, I could do the Jool transfer with 1x3 stacks, but it would take many hours of aerobraking, because without heatshields, aerobraking is less efficient. I have that much fuel only for my comfort.

The separation of Falcon in the Laythe landing configuration. I have 900 units of liquid fuel and 900 units of oxidizer more, than I need, and more than I want to have. The landing is really on the edge, and I can't risk it with that high mass. It wouldn't make sense, because I couldn't take off again, and I also wouldn't have the tank capacity for that much fuel..... I let you think for a moment..... If you think, that something strange will happen, then you are absolutely right. So, I have to burn that fuel or I have to drain it. I will burn a part of it for sure, so I have to do less aerobraking at Laythe. Probably I could do the landing in a completely different way, but I didn't practice that scenario, so I don't want to risk it. It's against my rules to test new scenarios after I've launched the real mission.

Adjusting the fuel priority, because it's messed up through the separations. The tanks will drain from the outside to the center, and the core at last.

Ready for the landing.... in the next episode.

Edited by DennisB
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  • 3 weeks later...

Episode 7 - Laythe and Vall (Part 1)    (Mar 28 - Apr 09, Mission Day 238-246)

This episode covers the landings on Laythe and Vall and the surface tour on Laythe. It took longer than expected, because IRL stuff held me back, and the game had again new (bad) surprises for me. Before this episode, I had to reload only 2 times, but on Laythe only, I reloaded 4 times, and Falcon is still sitting on the surface.
I already know, that I can't complete the mission before my vacation, when I will take a break of two weeks. It's doubtful, that I can complete my tour on Vall before it, and Jool and Tylo must wait for sure, until I'm back again. 

Overview of the situation


Sloth is waiting in its orbit around Tylo. Falcon is separated in Laythe orbit and ready to land. The Tree of Life has its capture at Vall in 4 days. Relay 2 has its circularization burn in 2 days, but I will do it now, because I will be busy with the other missions, and the relay constellation doesn't have to be perfect. In less than a half orbit I will complete the science collection anyway.




At Laythe


Bill is on EVA to prepare the aerodynamics of the Jool stage for atmospheric flight. I can't remove the decoupler, but luckily, the tube, which covered the engine, disappears when I switch to the vessel again. Putting on a nose from a fuel tank, which won't fly into an atmosphere again.


Before starting the science collection, let's take a closer look into Falcon's cargo bay. I took here a slightly different approach, than at the other vessels, which were quite minimalistic. I have four spectro-variometers, because the atmosphere analysis is biome sensitive at flight and it gives more points for multiple copies. I have four mystery goos and science jr. They are not biome sensitive in flight, but Jool has only one biome, and I will have only one shot in the low atmosphere to collect multiple copies of them. I have only one of each of the other science experiments. The thermometer is biome sensitive in flight, but it doesn't give additional points for multiple copies, so I don't need more. The seismometer and the gravimeter I can use only on the surface, where I have time to do the experiments multiple times. In the other half of the cargo bay, there are 8 RTGs, which are enough, to power the propellers on Laythe and the reaction wheels on Jool. The three reaction wheels are necessary, to give some kind of stability in space and in thin air, because the thrust isn't aligned with the center of mass. There is a container for the surface experiments. At the back, there are the four science containers, and between them, because there was some free room, three tiny fuel tanks. Jebediah is the pilot of Falcon and Bob is the scientist.

Starting the science collection with a first small dip into the atmosphere. Flying high over Sagen Sea.

As I mentioned in the last episode, I have too much fuel on board. It's not enough to reach a low circular orbit with rocket power only, I still have to aerobrake. For the burns, I use the Rapier engine only, because of the imbalance, not with full thrust, but I'm not in hurry.

At the next orbit, flying high over Degrasse Sea.

And the first aerobrake maneuver. Another one of medium intensity and two small ones will follow with retrograde burns to reach a low orbit.


Draining some fuel to reach the planned mass for the entry into the atmosphere.

Fuel transfer for the correct mass distribution. The wings are empty, the four small fuel tanks at the back too, the larger tanks on the outside are partially filled. During the tests I noticed, that the wings are a weak part of the plane. I can't remove the landing gears from the side tanks, but I can reduce the stress with emptying the fuel tanks. And overall, I have to move the center of mass to the front, to not flip at entry. I want to land at a specific place, so I have to aerobrake during the descent to adjust my trajectory. My wing area isn't sufficient to maintain level flight with 50t, and I have only limited fuel to use jet power, so I have to be really precise. I think, the landing on Laythe is the most technical maneuver, I ever did. I needed more time to develop my Jool maneuver, but the result was less complex. It doesn't look that spectacular on the video, but I will explain the background, so you get an impression about what's going on.

I practiced the landing six times before I tried it for real. The first five ended in a crash. It was the same in the test mission. When I don't do it for several weeks, I have to learn the whole procedure again. My orbit in the test mission was lower, which made it more difficult to adjust my trajectory with aerobraking. My primary landing site is the little island east of the larger one. The secondary landing site is the peninsula at the west of the larger island, where Falcon is on the screenshot. I've chosen these spots, because they are on the equator, they have nearly flat terrain, and they are on sea level, which is essential for the landing, and very useful for the start to orbit. There's over a day until the capture burn of the Tree of Life at Vall, it's enough to land.


Landing on Laythe


Here is the uncut video of the entire landing procedure. As always, screenshots will follow.


Performing the deorbiting burn at almost the opposite side of Laythe. I do the adjustments by eyeballing. As I said, my orbit in the test mission was different.

Switching to prograde direction before entering the atmosphere, when no retrograde burn is necessary anymore. The cargo bay is open to collect more science. I will fly over an island soon after entry, and can catch multiple biomes.

Flying high over Shores.

Flying high over Peaks.

Flying high over Dunes.

I missed the Shallows, but now it's time for aerobraking. During the maneuver, Falcon is tumbling quite heavy, the reaction wheels and the correct mass distribution are essential in this phase. It would be cool to look at it, but I have to control the trajectory.


Switching to prograde again before the atmosphere gets too thick. The trajectory still overshoot the island, but in the thicker atmosphere there's enough drag, which will make it shorter. I mustn't overshoot the target, because I can't do a U-turn. I would lose too much altitude to reach the island.

It starts to be hot, but there's no danger of overheating.

Draining some oxidizer to reduce mass further. The planned fuel for the ascent to orbit is 2454/2486 LF/Ox, and I want to get as close to it as possible at touchdown. I will use liquid fuel with the Rapier engine in jet mode, but I will use oxidizer only in the final seconds with the four Twitch engines. If you haven't noticed them yet, they are mounted on the bottom of the plane. With that high mass, small wings and thin air, I can't land safe like a plane, I need the chutes and the rockets.

The trajectory looks good. I won't overshoot the island. I have fuel for a few minutes of jet power to reach the target, if I'm short.

Below 300m/s, starting the engine and pointing to the island.

Below 200m/s, starting the propellers too. As the jet loses thrust with lower speed, the propellers gain thrust through the thicker air. I adjust the propeller angle, based on speed and altitude, with the H-N keys. The task is, to reach the island before running out of fuel, at an altitude of over 1000m. At practice I was short several time, so I had to switch off the Rapier engine, when ran out of fuel, and did the final part with propellers only. As I wanted to deploy the chutes, the engine switched on again, because it's in the bottom stage. To avoid this, I switched the stages before my first real landing, but then the chutes didn't deploy, even they were in the first stage. I don't know why. I had to reload, because after I pressed Space multiple times, the decouplers detached all the chutes. This is the second landing attempt.

Draining more oxidizer before the landing. Then changing the propeller angle for slow flight. This increases the thrust at slow speed, and it's an efficient air brake at higher speed.

The next critical point, the deployment of the chutes. The first four chutes fully deploy at 1000m altitude, the other ones later. But already the first brings the plane almost to an immediate stop. I have to set my trajectory right in advance, to land, where I want. At the same time, I have to slow down below 95m/s before the full deployment. At higher speed, the forces would break off the wings and the fuel tanks.



At 500m, all chutes are fully deployed, and starting the propellers again with full thrust. The landing is really on the edge. I not only need the chutes and the small rockets to land, I need the propellers too, to not crash fully vertical into the ground. The distribution of the chutes and the fuel is well planned to keep the plane horizontal at full propeller thrust, to land on all landing gears at the same time. That's the reason, why I need a flat terrain. At the test mission I was really frustrated, because I crashed every time, but I did it earlier safely. After five crashes I noticed, that two chutes were in the wrong stage and didn't deploy. That was enough to not be horizontal and unable to use the propellers, and it ended in a crash everytime.

Switching on the rockets to reduce vertical speed.

A quite rough landing. As you can see, there is very little ground clearance, so I have to use a stiff damper setting on the landing gears, which isn't helpful in this situation. The position of the bottom tanks are limited by the docking port. The position of the side tanks are limited by the length of the ladder, because the kerbals have to climb back somehow into the cockpit. The position of the rear landing gears are that high, to reduce drag at water takeoff. I didn't mention it, but I had to switch off SAS, because wit SAS on, the wings would break off.

Transferring all the fuel into the three center stacks of fuel tanks, and draining everything, what isn't necessary for the ascent.


Filling a little fuel into the tail tank for a better balance during the flight tour. A little more would be better.

I'm sure, you already noticed the hydraulic cylinders on the bottom, and meanwhile you may think, what comes next. I don't want to carry all the fuel with me during the whole tour, so I will dump it here. It's easier to fly with 15t than with 50t. I designed the plane, to fly with the reduced mass, that's the reason, why it has small wings. On Jool, I will have additional wings on the detachable first stage.



Going further away to remove the chutes. I don't want all that debris at the landing site. It's cool, how explosive those chutes are. Are they made of the same material, than the solid rocket fuel?



Laythe tour part 1


Starting the science collection. Landed at Shores, with flag planting and EVA experiment.



Deploying the surface experiments. I don't have the grand slam experiment here. I wouldn't get my projectile up to speed in the atmosphere, and I didn't want to develop a different one for Laythe. Falcon is already heavy enough. I have 3 RTGs, because I don't have an engineer here. Falcon has only two seats, and I need a pilot and a scientist on the mission.

Switching off the controls of the winglets on the side tanks. I will deploy them via action group. I will use them as flaps at landing and takeoff, and as hydrofoils in the water.

The landing site, before starting the tour.

Not far away, there is a boulder. I don't even have to take off. Surprisingly, I have no problems with moving vessel, unlike on Eve.


A geyser is also in sight.




Bob's taking a cold bath to collect samples from the water.

Splashed at Shores, with all the previous sites visible in the background.

It's time to go up into the air, and fly like a plane. With the hydrofoils, Falcon can glide stable on the water with 30-90m/s, and it has a minimum takeoff speed of 50m/s.



Flying low over Shores.

Flying low over Shallows.

Heading west to the bay, where my secondary landing site was. There is the first special place for science collection.


A safe landing on the water.


Splashed at Shallows.

Climbing out of the water.

Landed at Shallows.


And there is also a stone not far away, so I can get rid of the scanner arm.




I like to take off from flat terrain or from water, but downhill is also OK as long as it isn't bumpy.


Heading northwest to Crescent Bay, and taking some other biomes on the way.


Flying low over Dunes.

The first landing on land. Luckily it isn't bumpy. I soften the dampers, but if I hit a bump at around 30m/s, I get airborne again, but at that speed I can't control the plane and it most likely ends up crashing into the ground with the nose.



Landed at Dunes.


The next part of the tour goes over the sea, there's enough time to climb up high. Flying high over Shallows. I didn't want to take high atmosphere science, like I did on Eve. Luckily, it's much easier to construct a plane, which can fly up to 10km on Laythe, than one, which can reach 22km on Eve. If you remember, it took 30 days to collect space science over all biomes, and in the atmosphere I can do only 4x time warp. As I built the plane, I reached 13400m altitude, but it was with the old wings. At first, I had structural wing, but they had nearly the same size as the delta wings. I switched them, as I designed my flight on Jool. I need there more liquid fuel for the final stage. On Laythe, they were empty at the descent, and will be only partially filled at the ascent.

Flying low over Sagen Sea.

Arriving at Crescent Bay, and climbing up high again, to collect all science.

Flying high over Crescent Bay.

Flying low over Crescent Bay.

Reaching terminal velocity at the descent.

Splashed at Crescent Bay.

Heading to the north pole, to the second special place for science collection. That mountain is on the way. Perfect.

Flying low over Peaks.

I haven't practiced the landing at such a high altitude. Maybe a mistake, because the air is much thinner, but luckily, the terrain was flat, and the plane behaved really well.


Landed at Peaks.


The Tree of Life has four hours until its capture burn at Vall. The maneuver node doesn't look like it should. It should be at PE. After many bad experiences, I don't trust the game. I will pause my tour on Laythe, and focus here. I don't want to miss the Vall encounter.


At Vall


Capture burn at Vall.

And the circularization.

Transferring fuel to Jellyfish, and making inventory. If I have enough fuel to land Wasp on Vall and to fill Jellyfish, then I don't need a refueling mission. I want to land on the equator, and the biome constellation on Vall is like, that if I visit all the biomes, I will come back to the same place, where I started. So I wouldn't need two landings.

There's enough fuel.


I still can drain some liquid fuel, to match the level to the oxidizer.

Another fuel transfer for the right mass distribution.

Decoupling the LF tanks. Wasp uses LFOx, Jellyfish is full, and at Tylo I don't refuel the mothership, so there's no need for the tanks anymore.

That basin in the center will be my landing area.



I almost messed up the landing (I was too tired on that evening), but I survived. But I forgot to take the extra probe core to the surface. On the other moons, it wouldn't be an issue, because of the second landing, but here I don't want to land a second time.


The fuel production is running, and the surface experiments are deployed.

Meanwhile, on Laythe it's night time at Falcon's position. Because I want to fly at daylight, there is time for Projectile 3 to crash into Vall's surface.



This time, there's no reduction for the distance. Maybe, too close isn't good. But the impact energy is only 23%. It looks like, on larger bodies, a greater impact is necessary. Maybe I have to improvise something at Tylo. I didn't do this experiment on Tylo in my test mission.



Laythe tour part 2


Waiting for sunrise, and then flying at the terminator to the next destination.



Vall can be really huge in opposition.

The polar ice cap gets visible. I noticed here, that my course lead me to the wrong island. After it, it was clear, that I will arrive in the darkness, what I didn't want.

Flying low over Poles.

Flying high over Poles. The landing spot is on the right end of the island.


Splashed at Sagen Sea. Close to the biome border, which runs here also over the ice cap.

Splashed at Poles.

Unfortunately, I can't climb onto the ice, so I have to take off and land again, but at least, the ice is flat.


Landed at Poles with Vall at the horizon.



After rolling a little, landed at Sagen Sea.


The first two stages. But now, I will really wait for sunlight.

Meanwhile, Wasp is refueled, and it goes into hibernation.

The next stage of the tour will go over Degrasse Sea to Crater Bay. It starts to be boring. Long flights over the ocean, and I had to do them many times, because I didn't save frequently, and I had to reload multiple times for various reasons. Luckily, Falcon is much faster, than my Eve plane was. I had there much longer uninterrupted flights, but there I flew at least mostly over land. This is the last island before the open sea.

Flying low over Degrasse Sea.

Splashed at Degrasse Sea.

Flying lower with a higher propeller angle improves the speed a little. At least something positive.

After an eternity, arriving at the perimeter of the crater. Starting to climb, to get low and high atmosphere science in a single flight.

Flying low over Crater Bay.

Flying low over Crater Island.

Flying high over Crater Island.

Flying high over Crater Bay.

I managed to land exactly in the largest gap between Crater Bay and Crater Island biomes, so I had to cruise quite a lot on the water. KerbNet would be really useful here, but I can't use it on Laythe. I could glide much faster on the water, but then I have to take off, because I can't stop safely.

Splashed at Crater Bay.

At that distance, I decided to do a short flight to the island.

Splashed at Crater Island.

Climbing out of the water extreme carefully. I don't know why, but at this maneuver I had an engine failure multiple times. I thought about the reasons. Was it, because the coast is so steep, that the propellers touched the water, or because the cargo bay was open? But none of them is plausible, especially as I looked back the screenshots, and saw, that at the Shallows biome, I did the same, without consequences. With three propellers, I couldn't go straight, and if I switched off the engine on the opposite side, it was quite difficult to take off. I could fly, but with only two propellers, it's impossible to reach orbit. I had to reload. Maybe the island should be called Kraken Island.


Landed at Crater Island. The final biome.


The route at stage 3.

After a longer break, to do the final stage in daylight, leaving the island to fly back to the starting point.

After an hour long flight over the ocean, preparing for the final landing. This one is probably the most difficult, because the terrain here is quite bumpy.




The surface experiments need more time, in that I can do the tour around Vall, but that's for the next episode.

Here is the final stage of the tour. I collected splashed science from 8 biomes and landed science from 7 biomes.


Here is a short video of Falcon, which shows its flight capabilities on Laythe. The footage isn't from the actual mission.


Edited by DennisB
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