Real Solar System career using stock parts and *no contracts*

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Inspired by this challenge thread: 

I wanted to take things up a notch and attempt this challenge with the RSS mod using only unmodified stock parts.


To state the obvious, RSS makes things far more difficult. Here's a dV chart. For example, just taking off from Earth into a stable orbit takes more dV than taking off from Kerbin and landing on any body in the Kerbol system. Landing on the Moon and returning to Earth takes ~17.5 km/s dV while landing on Eve and returning takes ~14 km/s dV

No contracts means that money can only be made on automatic world firsts. The lack of low dV options in RSS makes things especially difficult near the start, as we will have to progress very quickly and cheaply with low tech and few building upgrades or we'll run out of money. I'm not really sure I can pull it off but it will be fun to try. My first attempt flamed out pretty early due to a series of compounding errors, but I got close enough to make me think it's possible and I've decided to document my second attempt here.

The game mode will be normal with no options changed. I'm also going to follow self-imposed rules of no strategies via the admin building, no clipping of non-structural parts, no ISRU, and no science lab. The mods I'll be using are Mechjeb, KER, Mechjeb for all, automatic science sampler (runs experiments automatically), better time warp, and RSS with the minimum number of required mods (Kopernicus, RSS textures, etc.). I'm also using KSP version 1.7 even though it is not officially supported by RSS. Without further ado, let's get started.

The first three launches

First we dip into Earth's upper atmosphere over 50km, landing splashed down at the shores for 70 total science. Using girders as decouplers helps us get high on the first launch, and using 3 goo canisters on the command pod (coupled with lots of spinning) lets Bob shed enough speed for his parachute to function properly.



Next we spend almost all our science on science tech and we get our first taste of space past 140km. The main purpose of this launch is to grab some extra science so that we can have both the Science Jr. and some basic wheels for our science car (coming up next) and also so that we can have as much science as possible for the launch after next when the real fun begins. 



The third launch is a pretty standard science car for running experiments around the KSC. Jets facing forward and back prevents us from getting stuck running into buildings, and the experiment storage unit allows us to keep two copies of every goo/materials experiment. We are successful in mopping up every bit of science, leaving us with 519 unspent points.



That concludes the easy portion of this challenge. Tune in next time when we will try to run a mission with almost as much dV requirement as a Tylo or Eve landing and return with only a single building upgrade.

Edited by bayesian_acolyte

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The most logical next step would seem to be getting to orbit, which is no easy task with a launchpad upgrade being the only building improvement (we had 188k funds and no upgrades after launch 3 and then spent 50k on upgrading the launchpad). However just getting to orbit and returning to the surface wouldn't give us quite enough funds for a VAB upgrade, a science upgrade, or another launch upgrade. So we would still have to get to the Moon or somewhere else with the same restrictions, and any Moon launch will get all the Orbit bonuses anyways. So if we can't get to the Moon on these launches, our journey would be effectively over.

Launches 4 and 5: Moon orbit




Doing this crewed was out of the question, as probes allow far more precious dV. The part and weight limits were quite restrictive. After much testing and many redesigns, the above ship is what we launched. It is tricky to control with no reaction wheel, especially the first solid booster stage with no engine gimbals, so the strategy was basically to launch it and reload until it happened to drift in a desirable direction.HrLcQdW.jpg0jhgYF2.jpg

Orbit achieved! To get into a Moon orbit and return, we will need about 4k dV from low Earth orbit. We are a bit short here with 3.3km/s, but we were only able to get this much because we launched without any batteries (or solar panels which we didn't have enough science to unlock) or a parachute for the return. These are left for the next launch:


This launch will deliver a drop tank, battery, and parachute to meet up with the previous launch. The higher part count payload meant we had to use a lower part count launch vehicle. Notice the low TWR for atmospheric flight especially in the 2nd and 3rd stages (numbers in screenshot are for vacuum), we actually lost speed for a bit on the second stage. A few designs with more normal TWR were also tested, but extra dV of this one (dV in the screenshot is correct and fuel in the drop tank is not included) made it more efficient. At least this time we have a reaction wheel.SF2mDda.jpg

Orbit achieved with most of the fuel left in the drop tank. It took about 10.6 km/s dV to get into orbit because of bad aerodynamics and lower TWR.


Meeting up with first launch was a bit tricky with needing to conserve fuel, limited battery, and no maneuver nodes. The strategy was to launch into a slightly wider orbit of the same inclination, then fast forward until the ships were close to each other, and then gradually edge closer.


Separating the delivery vehicle for the 5th launch.


We burn prograde at what looks the ascending node for the Moon with all the fuel in the drop tank, after which the drop tank is dropped. We flip around to retrograde before the separation to get a little boost. Any orientation changes with no reaction wheel requires a tiny burst of a burn with full gimbal and then waiting until our craft rotates to the desired direction.0QruitU.jpg

Without maneuver nodes getting an encounter was slightly tricky but not bad. We used a test run to find the exact time the Moon would be at the desired intercept point and the travel time it would take to get there, and then used this info to time the final burn from LEO. 


After a brief capture burn we have a highly eccentric but stable orbit. We are barely still in antenna range of Earth.


We need the cash for the "started constructing the first station" and docking maneuver firsts around the Moon, but there was an oversight in the design: our batteries are attached to the other side of the docking port, and without them we have no control (we can't transfer resources by moving charge to the probe core's built-in battery until we upgrade the science building). After some stressing and testing a workaround was discovered. Set thrust to 2%, engage full throttle, undock, quickly time warp and then normal speed to freeze the rotation of the undocked part, and then wait for docking to occur automatically. 


A quick AP burn retrograde gives us a suborbital first as well, and we are ready to return.


We use all our remaining fuel to kick out into a steep intercept course with Earth. I thought we would need a shallower entry angle but decided to play it out anyways.


The probe's light weight and relatively large surface area make for excellent performance in reentry, and despite hitting the atmosphere at 10.5 km/s orbital speed and a steep angle the probe survives.



The world firsts for our return have us ending up at 493k to spend on some building upgrades and our next mission.

Edited by bayesian_acolyte

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My hope for the next launches was to do a manned science mission to orbit Venus and return. Unfortunately with our limited budget and building upgrade options, I could not make this a reality, and this will have to wait for the next installment. Instead we move to a backup option, sending a probe to Mars. But to do this, we would need solar panels, which we were just 20 science short of. I also decided to pick up some deep sea diving world firsts.

Launches 6 and 7: Deep sea diving and some quick science


Here is our submarine:


You can be forgiven for thinking this looks like a plane. To get the deepest 750m depth bonus, we have to get a ways off the coast, which would be difficult without flying.


We fly for a while until we are almost out of fuel, which makes us light enough to land on the water without damaging anything. Then we dive.


We get the lowest bonus at 750m before floating back up to the surface and recovering. We end up making almost 50k with very little money spent.


To get enough science to unlock the first solar panels, we just need to land in a nearby forest biome.


Our lightweight plane does the job with ease.

Now on to the main event, a probe to Mars and hopefully Phobos and Deimos as well. Initially I hadn't considered this an option, as we don't have any antennas unlocked which have enough range for Mars. However limited probe control is still probe control. Only being able to turn the throttle full blast or off is an annoyance but is not debilitating, as is more limited control over our direction. We won't have enough dV to return after visiting the moons so this is a one way mission. I opted for upgrades to the tracking station and VAB, which left us with 166k.

Launches 8 and 9: Probe to Mars, Phobos, and Deimos




This design has 11 distinct stages. Upping the part limit to 255 increases our dV substantially while also increasing the cost.



In a stable orbit with about double the dV of the first launch of our Moon probe.


Doing this mission in two launches increases the fuel available, which means more moon action. It also allows us to pick up the coveted "building station" and docking world firsts. However it still feels a bit weird going through all this effort just to add a small fuel tank. This isn't like building a ship in orbit of Kerbin.


We don't yet have maneuver nodes, but it is very nice to see ascending/descending nodes and intercept points this time around.


With docking complete we have 7.1km/s dV remaining in low earth orbit.


With no maneuver nodes, the burn to Mars was a big pain in the ass. I had to actually break out some real life math. Eventually a solution was found and the burns were done in 4 stages for the sake of efficiency.k6cDxuR.jpg

Normally making fine adjustments to this encounter to get right where we want would be trivial. However with no throttle control besides off and on, and no reaction wheels to control where we point without burning (which would mess up the encounter), we had to wait until we were close to Mars to refine things so that our course was not as sensitive to our inputs.


This is a pretty good ship for aerobraking, but the sensitive solar panels and our difficulty in making fine adjustments made things difficult. We ended up losing one of our solar panels, so without batteries we will have to be careful of which way we are facing from here on out after each burn.


Now in a stable orbit of Mars, we pick up the docking bonus (we got the one from the Sun earlier). Only the docking port is left from the other ship, but it is enough.


Our difficulty in making adjustments has left us with one of the worst orbital angles to make a rendezvous with Phobos. This was an extremely difficult encounter to find without maneuver nodes, and despite being about 50km away it is still not within Phobos' sphere of influence. We have to make some post-burn adjustments when we get closer.lcVDZ9Y.jpg

The encounter will not last long enough for us to make our normal retrograde orbital burn to capture, so instead we use a retrograde target burn before the encounter. We end up using about 2,500 m/s dV for this capture burn, about 2.5 times as much as normally needed if we are coming from the same plane, leaving us with a bit over 500 m/s left. It might have been possible to go back and redo the Mars adjustments to reduce this, but at this point I was beyond caring. We should still have enough fuel to get most of the firsts that we came for.


Is it possible to touch the surface without the ability to make a real breaking burn? Let's find out.kO5CmoQ.jpg

We end up bouncing off at about 11.2 m/s, enough to explode our two docking ports but damage nothing else. This is perfect as we don't have enough dV to capture at Deimos and get docking bonuses there, and shedding that weight gives us about 70 m/s extra dV (we already got the docking bonus here).


This encounter was in some ways far easier to find than Phobos as we were starting on the same plane as Deimos, but the difficult part was our very limited dV and ability to change direction. With our now high TWR (our 500 m/s remaining dV is only a 7 second burn), any burn to start the craft rotating to the direction we want will have a significant effect on our course. But in the end an encounter was found with 14 m/s remaining.


With our final bonuses obtained, we are now content to let this craft drift endlessly around Mars.


The final total upon returning our view to the space center is 845k (including our previous remaining balance of 63k). This should buy us some nice building upgrades and a fair amount of wiggle room in our upcoming missions.

Edited by bayesian_acolyte

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Now that we have some funds secured, it's time go for some science. Next up is a manned mission to Venus and back. After building out the ship I had in mind, it had more dV than I thought it would, so the Moon is added as a potential extra mission target. Some of last mission's funds were spent upgrading the launch pad to max, upgrading the flight center for maneuver nodes, and upgrading the astronaut center for EVAs.Launch 10: Kerballed Venus orbit and Moon flyby



We take full advantage of the new launchpad upgrade with this 1.24 kiloton monster, as well as bumping up against the 255 part limit. Most of the weight is from the first two stages, which are both purely solid fuel for cost saving reasons. I wasn't sure what the dV requirement would be on this mission so I decided to plan for some extra. UMxCnMq.jpg

There was a lot of asparagus style staging in this design, with the engine staging taking up two full screens worth of scrolling on the side. 


We reach orbit with 6.1 km/s dV remaining. I could have earned some extra cash in this mission by going for the station building/docking bonuses on Venus. My original was to sit this craft on the launch pad, and then launch a minimalist hover plane from the runway and have it fly up to the top of the plane on the launch pad to add a docking port for these bonuses. However this plan kept blowing up in my face quite literally whenever I got within 200m of the launch pad, apparently due to some physics instabilities. I decided to go the lazy route and not get these bonuses this time around.ZxG0awk.jpg

It's so nice to have maneuver nodes! However we will soon lose this ability when we fly out of communication range from home, as we are only bringing a scientist on this mission. 


Aerocapture at Venus was a tense affair. 


Now in stable orbit of Venus, much science has been accomplished, and a few firsts have been captured. We are kind of in a weird spot here, in an extremely elliptic orbit of Venus with no maneuver nodes. However we have lots of extra fuel to get home so we don't need to be super efficient.


Finding the right window where launch window back to Earth that lines up with our extreme elliptic orbit proved difficult, so I decided to just kick out at Venus PE into a Sun orbit that overlapped Earth, and then use better time warp until an encounter showed up that was close. Then the orbit was adjusted to get inside Earth's SOI. CNFh7WD.jpg

The plan was aerocapture at Earth and then do a Moon fly by (we haven't got any Moon science yet), but the angle of orbit after aerocapture was looking pretty bad for this, so instead we opt for a Moon flyby with no capture at all when an opportunity presents itself.


After being kicked back out into another Sun orbit, 5 year later (this may be RSS but we aren't going for realism),we have another close-ish encounter. This will take a lot of dV to finagle but we have dV to spare.qwwxEHF.jpg

We make it back to Earth with just a bit of fuel left, which we burn off before attempting Aerocapture. The plan was to just blow up the Science module on aerocapture at this point, but I couldn't swing this without also blowing up Bob. After many attempts we settle for a more shallow partial aerocapture.HTSFI1s.jpg

After this first pass, before we leave the atmosphere we go nose up to burn up the Science experiment, empty fuel tank, and engine. The only way back is through some EVA pushing, and this will be easier with less weight. I don't like to abuse EVA pushing but this could have been avoided with the inclusion of a heat shield, which would not have made this mission any more difficult (seeing as we had 1.4 km/s dV remaining on our final near-intercept course with Earth). Also, you can almost always shave 2/3rds of the weight off the heat shield by deleting the ablator. I figured some EVA pushing was more desirable than redoing the whole journey. Live and learn.


The pushing doesn't take too long with the help of 10X physics warp. We shed enough speed to aerocapture then do a number of nose-in aerobreaking passes to shed speed before we are able to go ass-in and land without burning up.



The final haul is 2145 science and about 440k in world firsts (about 240k profit after out 200k ship is included). This will be enough to upgrade the science center and get some much needed technologies before our next mission.

Edited by bayesian_acolyte

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This is quite something. I've been playing RSS with stock parts for a while, did most of the tech tree in science mode, but this takes it about ten levels up.

Now if only playthroughs like yours could finally put the bed the myth that RSS "needs" part mods.

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I had the next mission planned and a ship mostly designed, but I got distracted by some real life stuff and then some other games. I still plan on coming back and finishing this. 

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Posted (edited)

After a long delay, we're officially back on! This seems like a good time to break down what our current and future options are looking like. This might be a bit TL;DR for some people so I've put most of it in spoilers.



First, one of the reasons I burnt out is how much of a pain doing missions without CommNet access and no pilots on board was, so I'd like to avoid this. Complicating matters is the fact that KSP did not design antennas for real solar system distances. The highest range antenna in the game talking to a KSP base with maxed out tracking station has a range of about 1.1 AU, which is enough for pretty much anything in the Kerbol system, but is a good deal less than the average distance from Mars to Earth and is pitiful compared to the 5+ AU of Jupiter's orbit. Disabling CommNet is a possibility but is too much like admitting defeat. So that leaves Kerbed missions, and since I don't believe in leaving anyone behind, that also means returns.

Sending Kerbals to plant a flag on the Moon and return is the most obvious thing we have yet to do. However we can only earn 151k more in firsts from the Moon, and accomplishing that ~21k dV mission including over 13k dV of high-ish TWR ascents/descents for less than 151k cost is a challenging proposition. It is likely doable but the profit margins and net gain would be minimal. 

The next obvious choice is Mars, where we have around 200k worth of firsts left to collect. A Kerballed Mars land and return mission is even more challenging than the Moon, and once again would be difficult to pull off in a way that it would be profitable. However the fact that Deimos (a Mars moon) also has around 250k worth of bonuses left for us makes this a more realistic option, especially if we could combine the two. But adding a Deimos landing to a Mars landing stretches what is possible with our 197k funds we have remaining, especially without the full tech tree, and the potential net profit of ~250k would leave us only slightly better off than we currently are. 

The inner system isn't really an option. Entering Mercury's SOI from Earth takes more dV than any other planet in the entire system (~12k dV just from Earth to Mercury intercept), and landing is like Tylo on steroids. We already did everything we can on Venus short of landing, which isn't an option with it's absurd atmosphere (not sure stock parts can even survive) and estimated 27k dV surface to orbit.

That leaves only Jupiter and the other outer planets and moons. The lowest dV Jupiter moon implemented in RSS (Callisto) is about 21k dV one way to intercept, or ~33k dV to land and return, which is not possible with our current situation, even if we could pull off multiple gravity assists.

It's kinda sounding like we are screwed. But not so fast... Saturn may be further than Jupiter, but it has two moons in Titan and Iapetus which aren't quite as far down it's gravity well as Jupiter's moons. Titan being the only moon in the solar system with an atmosphere provides dV-saving aerocapture possibilities, and Iapetus's low gravity makes landing there not too dV intense. I estimate a round trip landing on Iapetus after capturing at Titan will take around 24km/s dV, should net around 900k in world firsts, and is barely possible with our current 197k budget and tech without gravity assists.


So next mission is probably a Kerbed land and return mission to Iapetus. After that it gets even tougher. We will still be well short of the cash and science to get the final 1.6m research upgrade. I kinda hate using high dV ion setups because of absurd burn times, but we will definitely need them if we want to pick up enough of the ~14m in world firsts that are available in the moons of Jupiter, Saturn, and Uranus to close this thing out while remaining profitable enough. So looking beyond this next launch we will need a science mission probably to Mars and moons, and probably close to revenue neutral, and then figure out some way to make the final 600k-1m we will need to unlock and launch our first Ion ship and start the final phase of this project.

Edited by bayesian_acolyte

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this is some next level excrements dude! I didn't even know you could get off from earth with Kerbal sized rocket motors!

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Posted (edited)

Launch 11: Titan and IapetusOur next destination is Saturn and two of its moons, Titan and Iapetus. We've just unlocked the NERV, twin boar, and many other useful parts, which we can use to seriously boost our reach. This was a difficult design challenge with less than 200k in the bank and mission requirement of ~24 km/s dV including that murderous Earth launch. 



Most of the fuel is separated away from the rockets so that it can be staged off as it empties. Some solid fuel boosters help with initial TWR allowing us to carry more fuel tanks. These size 2 to 3 adapter tanks cost significantly less for the same fuel capacity compared to other tanks, and thus part of the design revolved around using as many as possible. This design enables lots of control over staging choices such as when to drop engines vs fuel tanks and how much fuel to include in each stage, making it easier to find and implement efficient stage breakdowns.


The second phase of the Earth ascent stages involves two high ISP Poodle engines with tanks sequentially staged off from the middle. These Poodles activate while there are still 3 Twin Boars active for a small TWR and efficiency boost. The last 1km/s or so of obtaining a stable orbit is done with the NERV atomic engine.


We are able to make it orbit with 14.6 km/s dV remaining, more than double our previous high. Here you can see the design of the upper stages with the familiar fuel tanks staging off as they empty. I also decided there was enough margin on this trip to include experiment storage, a thermometer, and a barometer. 


We go for a gravity assist via Jupiter mostly to collect some world firsts. Multiple correction burns are required for this trajectory, so in the end only around 500 dV was saved over a direct to Saturn route. The price of having an efficient upper stage is that this ejection burn clocks in at 28 minutes, which presented some accuracy and efficiency losses, but will likely be minor compared to upcoming ion missions.


12 years and 4 correction burns later, we arrive at Titan with 7.7km/s dV left in the tank. Titan is easily the best aerobreaking planet in either RSS or the Kerbol system, with an atmosphere 7 times the mass of Earth's but solid mass closer to the Moon, which makes the atmosphere extend far into space (in RSS to 600km). This particular aerobreaking maneuver saves around 3800 m/s dV and a lot more was possible.


We aerobreak juuust enough so that we are in a highly elliptic orbit. Pe is raised barely above the atmosphere, and next we find a window where a burn at Pe can get us near Iapetus.


Touchdown at Iapetus!


We have some extra dV so we do some quick biome hopping. We were able to land in 4 out of 6 of Iapetus's biome before heading back.


We launch from Iapetus and kick out into an orbit around Saturn very similar to that of Iapetus, wait for a window, and then boost for home. We will still have around 500 km/s dV left after the burn.


Despite entering Earth's atmosphere at over 16 km/s, our tiny weight and relatively large heat shield make re-entry a breeze. We glide down to a gentle splash with the EVA suit's paraglider.mGxhvks.jpg


We end up raking in 1.55 million funds via world firsts to go along with 3876 science, far better than expected. The final science complex upgrade is 1.69 million, and we have plenty of science for the final techs, so now we just need one more mission to earn some cash in order to unlock everything we need to make Ion upper stages and reach the 30k+ dV targets.

Edited by bayesian_acolyte

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Posted (edited)

Launch 12: Landing on Mars and its Moons

Next up we go back to Mars, this time with a pilot, a lander, and a return ticket. We are feeling good with 1.6 million funds and lots of science, but we still need to be conservative with our money as we save for the research upgrade, and the science doesn't do much for us without that upgrade (we now have a bigger fairing and a new science experiment). I'll admit I was tempted to go for broke here and try to spend it all on a mega craft to visit a number of new outer system moons in one launch with our current technology. My early design draft of a ship indicated it was maybe possible. However in the end I was swayed by this being my first time playing RSS and landing on Mars being something I've wanted to try for a while.




We are using an updated version of the previous launch vehicle and main interplanetary stage. This second iteration has slightly better aerodynamics on launch, slightly higher TWR, some upper stage modifications for our new mission, and a new final stage. Although I made some effort to keep this ship within the efficient minimalist spirit of this career, our previous mission has bought us a bit of a comfort zone, and to save development time this craft's capabilities far exceed this mission.


High average TWR in early stages and good aerodynamics lets us make an aggressive gravity turn with a shallow ascent angle.


We make it into orbit with almost all of our nuclear fuel still intact. Next we set up a 4.3 km/s dV burn for Mars.


H4Y9KuE.jpgAs Mars approaches, we transfer fuel to forward tanks to shift our center of gravity. We need to keep our not-very-aerodynamic front facing forward to get max aerobreaking and protect our pilot. This is also the purpose of the wing brakes near our engine.


Our aerobreaking is successful and puts us in a highly elliptic orbit. After a few more aerobreaking passes to lower our dV, I get bored and do the final 600 dV of orbit-lowering with our engines.


Now in a low orbit, we undock the lander/ascent vehicle.


Mars' atmosphere has less than 1% of the pressure of Earth's, and orbital velocity around Mars is also higher than Kerbin and almost 3 times higher than Duna, which makes aerobreaking difficult. To slow down enough for our parachutes to function, we use some sideways wings and 5 frontally exposed fuel tanks, combined with our light weight.


Once speed gets below ~850m/s, the drogue chute is released and the craft is flipped. The regular parachute is deployed right after it becomes "risky" and then the wings are ejected from the bottom. The 8000m land altitude of our randomly chosen destination makes things more intense than anticipated. The terminal velocity of the craft with parachutes deployed is around 40 m/s as ground approaches, and the last little bit is done with our engine.


Valentina strikes a pose (the part on the ground is detached parachutes). 


After the photo-op, Valentina gets back in her vehicle, trying not to dilly-dally too long to miss the launch window which she landed in. Using the target on the track ball helps execute a dog-leg ascent to almost exactly match the inclination of the craft she recently left. DV charts list Mars as a 3800 m/s ascent, slightly more than Kerbin, which is why our small ascent craft has 3 stages.


Orbit achieved, we dock with the rest of the craft with around 500m/s dV left in the ascent vehicle's tank.


Next we head for Phobos. We've already landed here with a probe, but still have some Kerbol and return related world firsts to get here, along with some science.


Unfortunately in our haste to leave Mars, we forgot we only have one flag and needed to take it with us. Not a big deal, we should still have plenty of cash without the flag planting world firsts on Mars' moons. We hop around to all of Phobos' biomes, which the minuscule gravity causes to take almost no dV but plenty of real life time.qHISWZa.jpg

After leaving Phobos, Deimos is next on our itinerary. 


On Deimos there is a repeat of the familiar biome hopping song and dance.


Having gotten almost every single world first near Mars (on return), we start a burn back for earth. In the above shot you can see a part of the design that was never really used, with extra oxidized fuel tanks on the top of the nuclear section to transfer fuel back into the last stage (which mostly exhausted its fuel on the Mars ascent). This means that after finishing this burn back to earth, we still have almost 5k dV fuel, which feels like a waste.


Some of that fuel comes in handy with breaking burns near Earth, as the ability of this craft to deal with re-entry is not nearly equal to the heat shield design of our last mission. FIAaGlZ.jpg

We make a nice easy splashdown with our paragliding vehicle.



The haul for this jaunt is 4713 science and +530k funds after all expenses, bringing our final total to 2.08 million funds. After upgrading the science building we have about about 390k funds left over. This career mode challenge ends after upgrading all buildings, and we should be able to earn the 3 million more funds we need to do that in our next launch. 

Edited by bayesian_acolyte

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Just so you know I've been reading this and loving it :)

I added a "Rogue's Gallery" to the challenge so I could put you in there SOMEWHERE.

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Posted (edited)

Holy [redacted]!!!!!! This is just incredible! I never thought playing RSS with stock parts was feasibly possible, let alone without any contracts or strategies!!! Just. Wow.

Edited by Thatguywholikesionengines

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Launch 13: Planting the flag on all of the moons of Jupiter and Saturn

Landing on all 11 of Jupiter's and Saturn's moons in RSS in a single launch seemed like a fitting send-off. The dV requirements for this mission are scary. Here are some rough overview numbers:

Earth's surface to Callisto's surface: ~24 km/s 

Callisto's surface to Io's surface to Callisto orbit: ~16 km/s

Callisto orbit (Jupiter) to Titan orbit (Saturn): ~3 km/s 

Titan surface to Iapetus surface to Midas surface: ~17km/s

Midas orbit to Earth's surface:  ~8 km/s 

That all adds up to 68km/s dV, but it doesn't include more than half the moons we are landing on, so the real number flown will be substantially higher. This will only be possible by getting the most out of our ion engines and because the whole ship doesn't have to make the whole journey. Calculating the dV of this mission seemed like a nightmare on both the requirement and capability side, so my strategy was to plan the landings/ascents, and then just build the highest dV craft with our budget that I could and hope for the best.


Two solid boosters and 6 more adapter tanks are added to the bottom stages from the last mission. The NERV stage is similar. The main question with ion engines is always electricity management, and our answer will be a single RTG recharging 11,000 main battery capacity, enough for a ~23 minute burn with our single engine. Using one RTG is the only way we can afford 5 large xenon tanks.


LEO is achieved with about 5.3 km/s left on our NERV.


The 6.6km/s burn to Jupiter is split up into 8 parts for max efficiency with a node splitting mod. However more than half the dV of the burn needs to take place after our path leads out of Earth's SOI, and thus can't be split up.iwOEM0j.jpg

On the final part of the last burn, with the NERV stage discarded, our ion engine is about to run out of batteries with 1km/s dV left. Our only power generation is a single RTG, putting our engine down to 8.5% efficiency. The calculated remaining burn time in this screen shot of 1 hour and 21 minutes is for our engine running at 100%, which means we are looking at about 15 hours of a horribly inefficient burn as we slingshot away from earth.


With 300 m/s left, we've already burned through a fifth of all our xenon fuel for this mission, and we momentarily pause to discard a tank from the middle of our stack (undock top of ship, undock tank, re-dock top of ship). The better time warp mod with its increased physics warp speeds was crucial here. You can see from the difference in dV in the above shots that we spent 1800 dV worth of fuel for about a 700 dV change, for an efficiency of 39%. Not the best start.


Arriving in the Jupiter system a few years later, we execute a 240 m/s capture burn right at the edge of Jupiter's atmosphere.


Now in a highly elliptic orbit, we burn about 150 m/s to get a gravity assist with Ganymede. The purpose of this assist is mostly to help our inclination, which will make it easier to to do future assists.


After another Ganymede assist to match our inclination to Jupiter's moons, we execute a long series of gravity assists in an attempt to raise our PE to near Callisto, the outer most moon, and lower our AP to something more reasonable. Finding gravity assists in the Jupiter system is not overly difficult with the large moon sizes, quick orbital periods, and matching inclinations (within 0.4%).


I didn't count how many gravity assists, maybe 10. It didn't save much dV over using Callisto to capture directly into this orbit from Earth, probably under 1 km/s, but dV is very precious right now when we are this heavy. Eventually we get the orbit we want, shown as the faint red in the above screen shot as the final gravity assist. From this orbit it takes about 150 dV to raise our PE out past Callisto into a safe parking orbit.


We detach the top part of our ship into a parking orbit to be retrieved later, and then make a small burn into a Callisto encounter.


Our batteries can support about a 23 minute burn, and this capture burn would take about 26 minutes, so the difference is made up by setting our thrust low enough not to drain batteries and starting the burn early. Once we are closer to PE the engine is set to full thrust, and capture is finalized with depleted thrust after our batteries run out. 


We take a number of burns to get into a low orbit and then detach our lander, which consists mostly of our ion engine, RTG, and a bit over half our batteries (12 minute burn). Callisto has a listed landing/ascent dV of 1.8 km/s each, which is a bit outside the 3.3 km/s range of our small ion vehicle. Our TWR would also be low and cause efficiency losses, and we don't quite have the battery power. So to make this possible a small booster was pre-attached to the top of the craft made up of 2 oscar tanks with 2 ant engines. About 75% of the booster's fuel is spent on landing with the last 25% on takeoff, always at the same time as the ion engine. When the booster is spent, it is discarded and falls to the moon below.


We complete the first of many landings and fast forward a few hours so our batteries can recharge. 8b2uekM.jpg

After completing the ascent, we re-dock, transfer fuel back into the lander, and then plan a burn to Ganymede.


With our now somewhat lighter weight, capturing at Ganymede is within our battery's capabilities. The burn to Ganymede, capture, and orbit lowering take around 3k dV, and we use up the last of another large Xenon tank. We then reconfigure by undocking a booster from the top and then attaching it to our landing craft, leaving the rest in orbit.


Ganymede is the largest and most massive moon in the solar system, and is even larger than Mercury. We use the same landing strategy as we did with Callisto, just with more fuel in the booster. Our margins are very thin, with this design actually failing every pre-launch test.Gbtu6vR.jpg

Landing is a tense affair, as laying off the throttle at any point means extra efficiency losses to gravity which are not really in our budget. Complicating the suicide burn is the fact that we need to land high in mountains to save fuel, and their variable terrain makes timing and angling the 12 minute burn difficult. My solution was mostly save spamming.


We are a bit short of making the ascent with our remaining fuel, so we leave around 8 m/s worth of fuel and get out and push. With no traditional command pod on this journey, we can't ever refill our EVA pack, so we can only pull this trick once. A stable orbit is achieved with less that 10% fuel left in the pack, and our inclination matching on ascent lets us rendezvous and dock with the 8 m/s remaining fuel.


Next up is Europa, the smallest of Jupiter's 4 main moons, but the 6th largest in the solar system. Getting to orbit from the surface takes the same dV as Duna at 1.45 km/s, but with no atmosphere and lower surface gravity.QOysrO7.png

The specs of this core craft match up nicely with Europa, and it is able to undock, land, and return unassisted.N5Q0Inw.jpg

Io is the last of Jupiter's moons for us to visit. It has the highest surface gravity and density of any moon in the solar system, with an ascent dV rating that ranks second highest to Ganymede. I9EuHiQ.jpg

After re-configuring to add the last booster to the core craft, we again leave the rest in a parking orbit and head to the surface. This setup is identical to the one we used on Ganymede, but Io's smaller size and mass gives us more margin for error.


After reaching orbit and docking we are left with 1840 m/s worth of fuel. The rest of our supplies are around 7 km/s dV away, high up Jupiter's gravity well. To reach them we will need to repeat a similar gravity assist sequence that we used when we first got here, and we start by burning a bit over 1km/s fuel to get our first boost off of Europa.


With the practice of our earlier gravity assist sequence, I am more confident in these maneuvers. This time we plan each gravity assist two ahead, adjusting after each assist so that we are lined up for one after the next one. 


After maybe 8 gravity assists we reach an orbit similar enough to our depot that we can match it with our remaining fuel. We split the matching burn into multiple maneuver nodes to meet up in a somewhat reasonable amount of time this far out.


We dock with 270 m/s remaining, transfer some fuel, and ditch a tank. After landing on all of Jupiter's moons and reconnecting with our other half, we are now ready to burn for Saturn.

To be continued...

Edited by bayesian_acolyte

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