User:Quizzical
My user page is no longer a red link.
I created this account mainly to post my game guide, which is available at Tutorial:How_to_Play. Rather than all of the theory, some people just want a vehicle that will work for a given purpose. As such, I'll explain the main vehicles I used for a run of recovering all science on the moderate difficulty level. I had an artificial rule for myself of no mining, and that does affect the vehicles I created. Furthermore, when recovering science, I wanted to deliver three copies to Kerbin, while keeping one copy on a Mobile Processing Lab MPL-LG-2. Surface features transmit with 100% efficiency, but this meant that for surface samples, mystery goo, and so forth, I needed four copies of each experiment result, three of which would be carried back to Kerbin.
As of this writing, the run is incomplete, so not all of the vehicles have their details here yet. I've largely designed most of them, but want to make sure that everything works how I expect before explaining them here and posting them in the Steam workshop. As such, this section is incomplete.
Landers
Landers are the vehicles that are responsible for landing on a given planet or moon to recover any science data that requires that you be landed to run an experiment. In places where this is relevant, they are also responsible for collecting science while splashed down or in flight in the lower atmosphere. Those require considerable thrust to move from one biome to another. Experiments run in space or in an upper atmosphere can readily be recovered from orbit and are not the responsibility of landers.
Different planets or moons called for different landers in a variety of ways. Even so, on a majority of them, my light lander could start in orbit, land in several biomes, and return to orbit to dock with a space station again all on a single tank of fuel. When that was possible, I used the same light lander in many places. When it was not possible, I built a custom lander for that particular planet or moon to optimize it for local conditions. The light lander does not stage, but merely refills fuel for its single stage. The other landers all have multiple stages as a way to get sufficient delta-v to complete their mission.
For Duna, Tylo, and Eve, it was sufficient to make a single lander for use everywhere. On Duna and Tylo, a single lander is responsible for landing in multiple biomes before returning to orbit. On Eve, it is enough to land just once, but the lander had to be capable of either landing on a slope or splashing down in an ocean. For Kerbin, it was also have been possible to use a single lander, but I customized it some for particular launches, such as replacing wheels by lander legs when I knew that I wouldn't need to drive, or eliminating early rocket stages when I didn't need to go far.
On Laythe, I needed two separate lander vehicles for two different purposes. The simple lander can land in one place, pick up science, and return to orbit. But there was also a sinker vehicle that was designed to pick up science from the lower atmosphere on the way down, then land in the water and sink to the bottom. It could pick up the science for being splashed down as it sank, then for being landed in the same biome upon reaching the bottom of the ocean. This allowed picking up the science while splashed and landed in the same biome from a single vehicle. It was also necessary to have something that could sink in order to be able to recover the science while landed in certain biomes that are entirely covered in water.
You cannot land on Jool, but you can pick up science from its lower atmosphere. I decided to list my vehicles for doing so in this section.
Light lander
The purpose of my light lander is to land on a relatively small planet or moon and pick up all available science there. It is intended for use on all planets or moons that do not have an atmosphere, except for Tylo. It offers 4197 m/s of delta-v in a vacuum from a full load of fuel. On Gilly, Minmus, Pol, or Bop, it can easily land in all biomes and return to orbit on a single load of fuel. On Ike and Dres, it may be able to do that, but it will be tight. On Mun, Eeloo, Vall, or Moho, you're going to need to refuel.
The lander has a mass of 11.255 tons, and its single Terrier engine provides 60 kN of thrust, for about 5.33 m/s^2 of acceleration with full fuel. That is plenty enough for any location that lacks an atmosphere other than Tylo, as the highest such acceleration due to gravity is 2.7 m/s^2 at sea level on Moho, which gives the lander a thrust to weight ratio just under 2. Naturally, the mass goes down as you burn fuel, ending at 3.255 tons, for about 18.43 m/s^2 of acceleration.
With lander legs retracted, the lander has 4.5 m of height, 3.3 m width, and 6.5 m length. With legs extended, the height increases to 5.1 m and the width to 5.8 m. The four LT-2 Landing Struts thus provide a rectangular base of support when landed that is 5.8 m wide on the short side, and a little over 6 m on the longer side. With a center of mass that is only about 2 m above the bottom of the extended lander legs, the maximum slope on which the lander should be stable is about 55 to 60 degrees, depending on how it is rotated. That allows landing absolutely anywhere on the various planets or moons for which it is intended except for certain portions of Dres's canyons.
The design of the lander is that the central column has, from top to bottom, a Clamp-O-Tron Docking Port, an SC-9001 Science Jr., a [[Mk1 Lander Can], a Probodobodyne HECS2 probe core, and a terrier engine. As these are all of small radial size, they provide good structural stability when connecting to other components mounted on top and bottom as part of a stack to deliver the vehicle.
The fuel tanks are a pair of Rockomax X200-8 Fuel Tanks, attached to the HECS2 probe core on opposite sides. The four lander legs are radially attached to the fuel tanks as high as possible, in order to bring the rest of the lander as close to the ground as possible. The mystery goo is right outside of the lander can door for easy access to reset it. This allows a scientist in the lander can to go on EVA, reset both the science jr. and mystery goo, pick up a surface sample and EVA report, and then return to the lander can all without needing to move around outside at all.
The rest of the equipment is radially attached to the fuel tanks to bring the mass as low to the ground as possible. That includes the other relevant science equipment: a thermometer, barometer, seismometer, and gravmax. It also includes a single PB-NUK Radioisotope Thermoelectric Generator to ensure never running out of electricity. I include three Experiment Storage Units, to allow pickup up four copies of all science as I move around: three in the storage units and one on the HECS2. This allows returning three copies of all science data to Kerbin, while having a fourth available for a mobile science lab. Returning three copies rather than one to Kerbin allows getting over 98.4% of the maximum possible science from all experiments that the lander will do. For comparison, a single copy would gather less than 80% of available science for three of them.
For communications, I use a Communotron 16, which is the weakest and lightest of the dedicated antennas, but still strong enough to connect to an RA-2 Relay Antenna in orbit 1000 km away with a signal strength over 0.997. As it has 100 times the antenna rating of the weak antenna built into the probe cores, this gives you ten times the range to connect to relays.
In testing, the light lander is a tough little critter. A free-fall from over 1.3 km on Minmus that resulted in hitting the ground at over 35 m/s did not result in any damage at all, even though I had enough fuel on hand to have a little under 2000 m/s of delta-v still available. That's the benefit of having lander legs account for about 12% of the vehicle's dry weight. It also landed quite easily on a 47 degree slope on Minmus, which is the steepest that I've been able to find there.
Kerbin lander
The Kerbin lander is built for a peculiar purpose that likely isn't what you want. Nevertheless, it fills its goal admirably well, so I list it here. The basic goal is to pick up all science from Kerbin's surface and lower atmosphere, including landed at the special biomes such as the island airfield. From there, load all science from a given run onto a detachable rocket that can deliver it to a station in space. Furthermore, keep three copies of all science picked up (both from the lower atmosphere and on the ground) on the base piece that is left on the ground when the detachable copy takes the fourth copy of the science into space.
This is handled in three basic phases. The third and final phase is to build a rocket that can deliver the science data to the orbiting station. Building a rocket that will work at all is not at all difficult. The real challenge is to make it as small and light as possible, and with a shape that will not cause trouble for the earlier phases. I use a fairly simple design with three rocket stages and an initial mass of 2.34 tons. There is technically a fourth stage to discard the Aerodynamic Nose Cone once the rocket is at a high enough altitude to no longer need it. Considerable testing found that putting an aerodynamic nose cone on top in spite of its small radial size offered the best performance even though all of the in-line components in the rocket are of tiny radial size.
The first phase is also pretty simple. Regard the vehicle for the second phase as a payload and put enough thrust behind it to deliver it into a polar orbit about Kerbin with enough delta-v remaining to land safely. Even if this is done badly, the worst that will happen is a waste of funds. My design uses a skipper and four thumper boosters at launch, then discards the latter before the former as they run out of fuel. That's not enough for a stable orbit, of course, but I get additional thrust from the second phase.
The second phase is the real challenge, for several reasons. For starters, some of the places that it has to reach are very small. The vehicle needs to be able to splash down at tundra, grasslands, deserts, and badlands, all of which are naturally land biomes. Lakes in them have to be very small in order to not register as the shores or water biomes instead. The special biomes such as Woomerang and the Dessert Launch Site are much smaller yet, and nearly impossible to land on directly from orbit without a lot of thrust happening near the ground.
The solution here is to build a vehicle that can drive around after landing. That way, instead of failing because you missed the center of your target by 10 m, you can just land within a few km, then drive to the proper location. Yet this also creates additional complications. For starters, rover wheels explode at 1200 K, which means that you'll need a much larger retrograde burn to land without blowing up. It's also naturally harder to land on wheels rather than lander legs, and you need to be able to drive up whatever slopes you encounter on the way to your target.
And then there is the problem of tipping over. Rovers are naturally prone to tipping over. Vehicles that splash down in the water are even more prone to tipping over. And rovers that drive into lakes to recover data while splashed down are especially prone to tipping over. The normal solution to all of these is to make your vehicle short and wide. But short and wide doesn't get a rocket into orbit while using minimal mass, as is needed to deliver the science into space. So that detachable rocket on top makes the tipping over problems much, much worse. Avoiding that in the second stage is the real challenge of the design.
The design of the second phase is to have a central column that is, from top to bottom, a Mk1 Command Pod, a Service Bay (1.25m), an SC-9001 Science Jr., an RC-001S Remote Guidance Unit probe core, an Advanced Inline Stabilizer, another 1.25 m service bay, and a dart engine. Science equipment goes in the top service bay, while electrical equipment and experiment storage units go in the bottom service bay. With a scientist as the occupant of the command pod, this makes it easy to go on an EVA, reset the science equipment, and board again without needing ladders. Sometimes you have to move slightly to reach the science jr. unit and sometimes not.
But the real key to the design is that it has four FL-T800 Fuel Tanks connected to the central column by Modular Girder Segment XLs. That gets you the wide base. Each fuel tank has two TR-2L Ruggedized Vehicular Wheels at the bottom, which allows you to drive. Each fuel tank also has an [[Aerodynamic Nose Cone on top, as well as four Mk2-R Radial-Mount Parachutes and one Mk12-R Radial-Mount Drogue Chute near the top. That provides enough drag to splash down without breaking fuel tanks even when the fuel tanks are completely full. Having lightweight gear extended far out from the center keeps the vehicle from tipping over even while splashed down, and regardless of whether the fuel tanks are full, empty, or anywhere in between. Each fuel tank is also connected to the top of the detachable rocket via a strut for stability.
When the second phase fuel tanks are empty, the second phase has a dry mass of 11.725 tons. Putting that on top of eight TR-2L wheels means that you have under 1.5 tons per wheel, so ascending modest slopes is easily doable--such as up the ramp to the Woomerang or Dessert launch sites. It's hardly the nicest rover to drive around on, but it's not bad, either, especially given that it has to carry around a rocket on top able to dock in space above Kerbin.
The lander can also pick up the science around the Kerbal Space Center by removing the first phase and having the fuel tanks of the second phase start empty. While there, you might as well pick up the science landed and splashed on the shores biome, with the latter available by driving into the ocean. And then you still have the rocket on board available to carry that science into space.
Duna lander
all land science, enough delta-v to hop between a few nearby biomes before returning to space
Tylo lander
all land science in vacuum, stages to land repeatedly nearby and then return to space
Laythe lander
all land science, stages to land on Laythe using parachutes, then return to space
Laythe sinker
all land science, stages to land in Laythe's ocean, sink to bottom, recover both splashed and landed science, then return to space
Eve lander
all land science, land either on land or oceans on Eve, then return to space
Jool diver
parachutes to slow fall near end, transmit manned science, die hope to figure out how to return kerbal to orbit, but hard
Jool probe
probe to recover all unmanned atmospheric science, return to space
Rovers
The natural purpose of a rover is to scan surface features. Unlike some science experiments, surface features can be transmitted back at 100% efficiency. Thus, you can scan a feature once, transmit the data, and have all of the science you can get from it, at least apart from taking the results to a Mobile Processing Lab MPL-LG-2. Surface features are in very particular locations, though, making it difficult to land in just the right spot to scan one. Rather, it is much easier to land close, then drive over to one. And to drive, you want a rover.
I task my rovers with some additional work. Rather than just landing a rover and scanning surface features, I also use them to deliver the deployed science. The basic technique is that the rover will have a small lander connected to it via a stack separator. The lander will have equipment for all of the deployed science, a command pod with an engineer inside, and some rockets that can get the engineer back into orbit. The plan is that I can land the rover, remove the lander from the rover, and then let the rover go scan all of the surface features and transmit the science. It can then bring a copy of all surface features back to the lander, where the engineer picks them up and takes them into orbit, to deliver them to a mobile science lab. If the rover breaks a wheel, there is conveniently an engineer right there to fix it.
Some of the deployed science equipment needs to be deployed by an engineer, and some by a scientist. I usually have only the engineer land with the rover, and a scientist can land nearby using the normal lander for that world, then stop over to deploy the science experiments. The lander has to land in that biome sometime, after all.
I use two different models of rovers, as different planets and moons have different challenges for rovers. In heavy gravity, even a mediocre rover design probably won't flip over apart from doing something dumb. However, it can be difficult to be able to ascend the hills in your path. It's frustrating to see the surface feature you need right near you, but you can't get there because it's uphill. As such, I have a hill climbing rover that is designed to be able to climb steep hills.
In light gravity, it doesn't take nearly as much force to drive up a hill. Furthermore, even if a hill genuinely is too steep, you can just fly over it by firing up rocket engines. Rather, the problem in light gravity is that the gravity doesn't do such a good job of keeping your rover upright. Rather, it is likely to be very prone to flip over, and then parts break off and the mission fails. As such, I have an "unflippable" rover designed to be very resistant to flipping over for use in light gravity.
The unflippable rover has rockets of its own, so it can deliver itself and the deployed science to the surface. The hill climbing rover does not have rockets or fuel to save on weight (and thus be able to climb hills better), so it cannot deliver itself to a planet. Rather, it requires some additional infrastructure to land it that isn't part of the rover proper. That additional structure varies by planet, as does the escape vehicle to return the engineer to orbit. And, for that matter, on Kerbin, you just recover the engineer and return only an unmanned probe to orbit, while on Eve, you the vehicle to deliver the rover doesn't have the capability of returning to orbit, which requires yet another vehicle.
Unflippable rover
The unflippability of the unflippable rover is slightly exaggerated, but only slightly. There are four basic ways that rovers flip over: 1) be on too steep of a hill, 2) accelerate or brake too sharply, 3) turn too sharply at high speeds, or 4) hit a ramp at high speeds to get off the ground, then turn over while flying.
The first cause is pretty obvious, and also applies to landers. The second will probably flip over the first rover that most people build. The third can flip over just about any rover, though some can handle much sharper turns at much higher speeds than others. Absolutely any rover that is capable of moving at high speeds is vulnerable to the fourth, though it isn't really that big of a concern, as it requires intentionally flipping over. The larger concern is landing wrong and breaking something in the process.
The unflippable rover is basically immune to the first cause of flipping, at least apart from extreme situations such as the canyons of Dres or certain parts of Kerbin's mountains. It is also completely immune to the second cause of flipping at least on Minmus. I've tried going downhill on a 45 degree slope on Minmus at more than 30 m/s, and then slamming on the brakes and accelerating backwards to slow as quickly as possible--and with the advanced tweakables adjusted to turn off traction control and maximize braking power. I came to a dead stop without the wheels ever leaving the ground. On that basis, it is probably completely immune to the second cause of flipping on Minmus and Bop, and possibly also on Pol. Likely not on Gilly, though.
The unflippable rover can be flipped by the third cause, but it is far more forgiving than most. The very low center of mass allows turning more sharply at higher speeds than most other rovers. In the light gravity of Minmus, it can make its sharpest possible turns at 5.7 m/s without wheels leaving the ground. It can also drive in tight circles at over 3 m/s while on a slope steeper than 40 degrees. Meanwhile, the high moment of inertia means that if the rover does flip, it will flip slowly enough that you can likely react in time to prevent disaster. Even if you do leave the ground, you may be able to fire the rockets to get enough height to reorient yourself and land safely.
So how do you design a rover like that? The basic size specs give a lot of information: 1.4 m height, 10.2 m width, 13.1 m length. The places where the four wheels touch the ground gives a support base that is a rectangle over 10 m on a side. Meanwhile, the center of mass is less than 1 m off the ground. If the rover didn't slide down the hill, that should theoretically be stable on an 80 degree slope.
The rover has a total mass of 12.79 tons with full fuel. It is fueled by two Rockomax X200-8 Fuel Tanks, which feed four twitch engines. That provides a total of 2793 m/s of delta-v, which should be plenty enough to land from orbit on any of the planets or moons where the rocket is intended for use, and then still have plenty more to fly around further if needed. The engines offer a total of 64 kN of thrust, which offers more than 5 m/s^2 of acceleration on full fuel tanks, increasing to 13.36 m/s^2 as they exhaust their fuel.
The rover is designed to have a Probodobodyne HECS2 probe core that controls it at the center. Two Modular Girder Segment XLs protrude from the front and back of it, with the two fuel tanks at their other ends. Two more such XL girders connect from the sides of each fuel tank, each with a TR-2L Ruggedized Vehicular Wheel at the end, for four wheels in total. That keeps the base of the rover very low to the ground, as it is all just off the ground.
All other rover parts are radially attached to the fuel tanks. The four twitch engines are attached in a symmetric manner such that the center of thrust is exactly along the center of the HECS2 probe core at the center of the rover. The other parts are distributed such that exactly half of the remaining weight is attached to each fuel tank, to keep the center of mass almost exactly at the center of the probe core. One end has only an OP-E Large Scanning Arm. The other end has a Communotron 88-88, two PB-NUK Radioisotope Thermoelectric Generators, and two Z-400 Rechargeable Batterys.
With all wheels in use, you can drain the batteries at a net 12.55 electric charge per second. With a capacity of 1800 electric charge in total, this gives you over 143 seconds of electricity, not counting any reduced power usage from motors not going at 100%, nor any recharging while you coast. You can also park to recharge your batteries.
I use the very powerful antenna because the rover has to actually transmit science. Furthermore, as it is completely unmanned, losing your connection at a bad time is much worse than merely falling back to crew control. The antenna is able to reach all the way back to Kerbin from anywhere in the solar system, or able to get a very strong connection to any space station, even around a different planet entirely. That means that even if by chance you can't connect to any of the relays about the planet or moon where the rover is, you'll probably still be able to connect to something else, at least unless you're on the dark side of Eeloo.
The unflippable rover is able to survive hitting the ground at over 15 m/s without damage. That it attempts to be so low to the ground prevents it from surviving some of the more extreme falls that the light lander can take. It also tends to bounce if you land hard, as wheels can't stick nearly as well as lander legs, so you do want to let it down gently, as with any other rover.
Hill climbing rover
The hill climbing rover is for those who, upon reaching a steep slope in a mountainous area, wish to just drive right up it rather than having to stop and go around. This means a very high wheel to vehicle weight ratio, in order to get sufficient force to drive up the hill. As being able to ascend hills safely is the driving reason for this rover to exist, it is quite good at it. While the design is relatively low to the ground, it is much easier to flip over than my unflippable rover.
As best as I can tell, there are only three places in the game where there are hills that the unflippable rover cannot ascend. One is the canyons of Dres, where the rover has ample drive force, but would flip and fall on the nearly vertical slopes of the sides of the canyons. A second is the mountains of Kerbin, where the steepest slopes that the rover can climb are about 70 degrees. That's good enough to climb most of the slopes in Kerbin's mountains, but there are some steeper than that. The third is in Eve's mountainous areas, which do have some steep slopes, even though most of Eve is relatively flat. Even so, the hill climbing rover can go straight up most of the slopes in Eve's mountainous areas.
The hill climbing rover is a single stage with no rockets. It crams six TR-2L Ruggedized Vehicular Wheels into a mass of 1.82 tons, meaning that those wheels account for more than a third of the total mass of the rover. Its dimensions are 5.8 m length, 4.5 m width, and 2.8 m height. That may not seem particularly low to the ground, but merely removing the rover arm sticking up reduces the vehicle height to 1.5 m. Also removing the antenna makes it 1.2 m.
Because it isn't as low to the ground as the unflippable rover, the hill climbing rover can't handle as steep of slopes. While stationary, it can handle slopes of a little over 70 degrees, but it becomes awkward to maneuver without falling on slopes over about 60 degrees. I managed to create an unrecoverable save file of the rover stopped on Kerbin on a 69 degree slope, as it takes a little bit of time for the brakes to kick in when you load a saved game, and that was enough time to pick up enough speed that trying to brake and stop would cause the rover to flip.
The design of the rover is to build around a [[Z-4K Rechargeable Battery Bank] as its main body component. It has a wheel attached to either side, as well as Modular Girder Segments on the front and back. Each of the girders has a wheel on either side. The rover puts the OP-E Large Scanning Arm necessary for its mission on the front, then puts three PB-NUK Radioisotope Thermoelectric Generator and a Communotron 88-88 antenna on the back to balance the weight of the scanning arm. Add an RC-001S Remote Guidance Unit probe core on top of the center and you have the entire vehicle.
The hill climbing rover is intended for heavy gravity areas, where the gravity will greatly mitigate the risk of flipping due to accelerating or braking too fast. Lighter gravity can handle a lot more mass while keeping the wheels per weight ratio high enough to maneuver easily. As such, the hill climbing rover is intended for Eve, Kerbin, Laythe, and Tylo. It is also used on Duna, where either it or the unflippable rover could work, even though neither is ideal.
Unlike the unflippable rover, the hill climbing rover has no rockets, and hence, no way to deliver itself to a planet. Reaching Kerbin is easy because you start there. The others all require a custom delivery vehicle to put the rover on the surface. The details here vary considerably from target destination to the next.
On Kerbin, the rover was not responsible for delivering the deployed science equipment. Rather, that was a separate vehicle that started at the runway, got out to deploy the equipment, then recovered the main vehicle. With no need to deploy science equipment, there was no need for a manned rover. Rather, it loaded a rocket on top to deliver the scanning arm science to space, then drove from the Kerbal Space Center into the nearby mountains.
(need to include some details for other places)
Space stations
Space stations serve several purposes, so the basic design is to add whatever equipment is needed for each purpose until you have everything. First, a space station must serve as a very powerful relay. I attach 16 RA-100 Relay Antennas. That gets you eight times the antenna strength of just a single RA-100 relay. With such a station at each end, even with Eeloo at its farthest point from the Sun, you can connect back to Kerbin at a signal strength of over 0.93. The idea is that you can have many light relays with much weaker connections that pass a signal on to the big station that sends it to other planets.
Second, a space station should have a Mobile Processing Lab MPL-LG-2. Other than on Kerbin, you do get a little more science for doing your lab research while landed rather than in space. But you're not going to start using labs until you've unlocked everything, anyway, so I just do it in space. In addition to the science lab, that means electrical generators to be able to run the lab and a place to store the data.
Third, there are some scientific experiments that are only done in space. You don't want to weigh down a lander or rover with such equipment, so I keep it on the station. That includes an [[M700 Survey Scanner, a SENTINEL Infrared Telescope, and a Magnetometer Boom. Both the survey scanner and the desire to use the station as a relay mean putting it in a polar orbit. You can get into a low enough orbit to do the science in space near the planet and the survey, as well as being near so that refueling is easier, and then later move to a higher orbit to be more appropriate as the long-distance relay.
Fourth, after setting up the deployed science on the surface, you want to be able to have something crash into the surface to complete the seismometer science. The space station goes at the bottom of my stack of vehicles, and is directly connected to the rockets used to deliver the stack to its destination. That allows removing all other vehicles while still being able to fire rockets to reposition the station. Once everything is done, you can disconnect the rockets in order to have a large vehicle that is no longer otherwise needed, so it can crash into the surface at high speeds and instantly complete the grand slam passive seismometer science. Or at least, you can so long as you don't have a thick atmosphere to slow you down, as you do on Eve and Laythe.
There are actually three different models of space stations. The main difference is whether they need to be able to refuel the lander. On Gilly, Minmus, Pol, Bop, Ike, Dres, Mun, Eeloo, Vall, and Moho, you do need to be able to refuel the light lander, so I added a Rockomax Jumbo-64 Fuel Tank, which has enough fuel to completely refuel the lander four times. That is sufficient in each of those locations. I also added the necessary docking port to be able to connect to the lander.
Elsewhere, the landers are disposable, so you don't try to refuel them at a space station. As such, you don't need the fuel tank or docking port. It is still convenient to be able to attach to landers easily, however, so I added an [[Advanced Grabbing Unit. That is simpler to use than a docking port, and still good enough for transferring kerbals and data, even if it can't transfer fuel. The station without fuel is used on Duna, Laythe, Tylo, Eve, and Jool.
For Kerbin, since that is where you are connecting back to, I made an alternate version that added many more relays. Rather than 16 RA-100 relays, I put 162 on a station and put it in orbit about Kerbin. That allows for a theoretical maximum range for a connection between the Kerbin station and any other of over 1900 Gm, or about 15 times the greatest possible distance between Eeloo and Kerbin. Thus, at normal difficulty, the connection strength between the Kerbin station and any other station will always be greater than .987, at least if they can see each other.
Science return
The idea of a science return vehicle is that it can pick up science data from around whatever planet or moon the stack was sent to, then return that data to Kerbin. I want to be able to bring three copies of data home, so that is done by storing it in two experiment storage units and a probe core. You add the needed communications and electrical equipment, as well as parachutes to be able to land. I also have a docking port as the way to transfer data.
There are two quirks to the design. First, it needs to fit neatly in a stack, which means a relatively short central column consisting entirely of in-line parts of small radial size. That is readily done by, from top to bottom, a Clamp-O-Tron Docking Port, a Service Bay (1.25m), an RC-001S Remote Guidance Unit probe core, an FL-T200 Fuel Tank, and a terrier engine. Then you add however many more FL-T200 fuel tanks you need via asparagus staging.
There are actually two different models, with different amounts of staging. With two extra stages (for five fuel tanks in total), you get somewhat over 5000 m/s of delta-v, which is enough to get home from most places. That's not enough from Moho or a low orbit of Jool, however. Those add extra stages for the other model.
The other quirk is that I don't put the Communotron 88-88 antennas on the final stage, as you normally would. Rather, I put them on the next to last stage. It is anticipated that you'll be near Kerbin by the time you get to that last stage, so the weak antenna built into the probe core will suffice. Depending on where you're returning from, you could have a 2000 m/s retrograde burn to get into a low orbit of Kerbin, which is more delta-v than the final stage contains. Discarding the antennas a little sooner allows that final stage to provide more delta-v.
Light relay
The idea of the light relay is that you put several of them around every planet or moon that you orbit. That way, rather than other vehicles needing to connect to relays that are very far away or even all the way back to Kerbin, there are several that are at most a few thousand km away. That allows even a weak antenna to get a good connection.
You don't want to rely on a light relay to connect all the way back to Kerbin, however. The idea is that if each planet or moon has one very powerful space station and several light relays, then you just have to connect to some relay, and the relays can connect to each other to eventually get your signal to the powerful space station. That space station is responsible for the connection across interplanetary space.
The reason to make most of the relays very light is so that it is easy to get several of them to a planet. If you just have one huge space station, then when you're landed, more often than not, the planet you're landed on will block your access to the station. It will similarly block your access to any particular relay more often than not. But if you have eight light relays plus a station arranged randomly, the odds that you can connect to something at any given time while landed are about 99%--and much higher than that while in a higher orbit.
My own light relay design is very simple, with specs of 0.65 tons of mass, 2.3 m height, 1.0 m width, and 1.0m length. From top to bottom, I have in order, an RA-2 Relay Antenna, a Probodobodyne HECS probe core, a Z-200 Rechargeable Battery Bank, an Oscar-B Fuel Tank, and a spark engine. There are two OX-4L 1x6 Photovoltaic Panels connected to the probe core, opposite each other for balance. The engine offers 1154 m/s of delta-v in a vacuum, which is plenty to move the probe cores from one high orbit to another.
Transporting eight of those at once with the ability to detach them from a larger vessel thus adds less than 6 tons of weight to the vehicle. They each have their own rocket engine, which allows putting the eight small relays into eight very different orbits. That makes it cheap and easy to set up a good CommNet connection about any planet or moon.
Electricity is an issue, but the built-in batteries can last 140 minutes without recharging. That can be greatly extended if needed by putting the probe core into hibernation mode. Furthermore, the solar panels will tend to recharge the batteries much faster than they drain even without hibernation mode as far out as Jool. It gets dicier for Eeloo at its furthest point from the Sun, but there, you can put the probes in orbit, then the game will never check their electric charge so long as you don't come close. Eeloo is also completely fine when it is relatively near the Sun, as it likely will be when you approach.
I use eight light relays about every planet or moon except for Kerbin. They aren't needed on Kerbin unless you disable the extra groundstations. "Every planet or moon" includes Jool, where you may want to send a probe into Jool's atmosphere, but does not include the Sun.
Stacks
The idea of stacks is that, even if I want several vehicles on a given moon, that doesn't mean that I have to launch them all one at a time. Rather, I can attach them all to each other so that I only have to launch one vehicle from Kerbin, then split it up into components when the combined vehicle reaches its destination.
Stacking several unrelated vehicles is pretty much guaranteed to give a combined vehicle with extremely bad aerodynamics. It is also going to be prone to falling apart. The latter is fixable by adding a lot of struts. Even so, you don't want a bunch of unnecessary struts still attached to your real vehicles after disconnecting them. The solution is to have reaction wheels with I-beams attached in between vehicles. The struts to hold the different vehicles together all have their base on an I-beam, so that they are discarded as debris after detaching everything.
Light stack
The light stack has several vehicles. From bottom to top, it includes a station with fuel, an unflippable rover, a light lander, a science return vehicle, and eight light relays. I put the eight relays under a single AE-FF2 Airstream Protective Shell (2.5m).
The light stack is used on Mun, Minmus, Ike, Gilly, Dres, Vall, Bop, Pol, and Eeloo. Well, I didn't really use the full stack for Mun and Minmus. I did use the component vehicles there, but sent them in two separate chunks as part of completing the technology tree. That allowed me to recover science from vehicles I could build, then have the others join them later.
The light stack has about 5500 delta-v remaining after reaching a low orbit of Kerbin. That is enough to comfortably go from a low orbit about Kerbin to a low orbit about any other celestial body in the game, except for Moho, Jool, and the Sun. Moho is the only one of those three that matters, as you can't land on the other two, making the light stack wildly inappropriate for the job.
As the payload is only a little over 100 tons, that's easily managed, and I use rhino engines so that I can mostly have acceleration around 10 m/s in space, rather than waiting a long time for nerv engines to finish their very slow burns.
Moho stack
The Moho stack is nearly identical to the light stack. The only real difference is that it takes more delta-v to get to and from Moho. As such, I wanted more stages on the science return vehicle to ensure that it would have about 7000 m/s of delta-v and could actually get back to Kerbin. Everything else about the payload was the same, however.
The earlier stages to deliver the payload to Moho were substantially different, however. Rather than face the enormous cost of adding additional stages to an already heavy vehicle, I kept a single rhino engine as its last stage, but moved some previous stages to nerv engines. The much lower thrust of the nerv engines means much longer burns to get to Moho, but it allows having a little under 9000 m/s of delta-v to get there from a low orbit of Kerbin at a cost of about 500k extra funds.
Duna stack
4x Duna lander, hill climbing rover, station without fuel, science return, 8x light relay, 3000 delta-v after reaching Kerbin orbit
Tylo stack
4x Tylo lander, hill climbing rover, station without fuel, science return, 8x light relay, 5000 delta-v after reaching Kerbin orbit
Laythe stack
8x Laythe sinker, Laythe lander, hill climbing rover, station without fuel, science return, 8x light relay, 5000 delta-v after reaching Kerbin orbit
Eve stack
station without fuel, science return, 8x light relay, 5000 delta-v after reaching Kerbin orbit.
Jool stack
station without fuel, science return, all non-landed science equipment, 8x light relay, 7000 delta-v after reaching Kerbin orbit
Custom vehicles
In addition to the stacks of vehicles that I send to various planets and moons, there are also some custom vehicles that I launch independently for a variety of reasons. In the cases of Jool and Eve, it is because all of the vehicles that I want to send to a planet collectively have too much mass to be reasonable in a single launch, so they have to be broken up. For the Sun, because you can't land there or even enter its atmosphere, there is only ever a need for a single vehicle to pick up the science in space around it.
On Kerbin, there is also the issue that launching many separate vehicles is much easier. In some cases, the vehicles don't even have to reach a stable orbit to complete their mission. As such, I don't list vehicles that were launched separately while staying near Kerbin in this section.
Sun science pickup
The sun science pickup vehicle is simple enough for their to be no need for copious details. The basic vehicle just needs to have a single kerbal (as needed for a crew report and EVA report) in a command pod (needed for the crew report) together with all of the science equipment for experiments that can be done in space. Bring enough experiment storage units for however many copies you want to return to Kerbin, and choose a scientist kerbal to be able to reset the science jr. and mystery goo units. That plus electrical and communications equipment is readily doable in under three tons.
After that, you just need to put enough fuel tanks and rocket engines to have sufficient delta-v to get there. From a low orbit of Kerbin, it takes about 4000-4500 delta-v to get your periapsis about the Sun under 1 million km, which is the threshold for being in space near the sun rather than high in space above it. You can pick up the science high in space as soon as you leave Kerbin's sphere of influence. Then you wait until you get near periapsis to pick up the science near the sun.
To get back to Kerbin, you wait until you are back at apoapsis, then burn prograde to make it so that the sum of your periods before and after the burn totals one year. That means that your two orbits about the sun will match one Kerbin orbit, and the next time you're back near apoapsis, you'll have an encounter with Kerbin. The prograde burn takes about 3000-3500 delta-v. You can fine-tune your encounter from the periapsis of your second orbit. And then, of course, once you have your final encounter with Kerbin, you'll need some more delta-v to land safely. A total of 10000 delta-v remaining after reaching the initial low Kerbin orbit should be sufficient.
