camacju

I'm actually not using the dragless fairing trick here. The air intakes are attached to the front of the fairing and offset backward, partially occluding the front drag cube face (the rest is done with fuel tanks attached to the interstage nodes, which is still a little exploity but certainly not on the level of eliminating all drag). This was to save the mass of an engine plate. I offset the air intakes backward to balance out the body lift of the fairing base, otherwise the craft would become very unstable around Mach 2. They produce the same amount of drag either way. (The fairing base is at the front so I can drop the jet engine out the back and avoid a lot of funny stuff with colliders). The Laythe lander is partially empty of fuel to save mass. As a result, it's very light, and has a lot of drag because a fairing was too heavy to be worthwhile. Also, I take a shallow aerobrake trajectory and angle the lander so the basic fins can provide lift. Note how reentry effects don't even show up on descent, because I slow down so much in the upper atmosphere that heating is never an issue. The problem with aerodynamic exploits is that they usually require additional parts, and the extra mass just isn't worth it for this mission.

Yet another Jool 5, this time optimized for low mass.

Another! 5253 kg by the challenge rules, 5184 kg without pilot or cargo

very impressive mission however physics exploits are not allowed

By the rules of this thread, this should be 1087 kg:

This was a fun challenge! It's my first time in RSS and I don't really know of the RSS-specific optimizations, but I think this did pretty well. Piccard III on the runway (Piccard I had issues with asymmetric thrust under high time warp and Piccard II didn't have enough wing area) Climbing to altitude Settled down at Mach 0.6 and 2 degrees angle of attack. This is close to optimal for subsonic range with the Goliath engine, and this craft is designed to fly subsonic so I can get it off the runway more easily. Supercruising with the Goliath gives more range, but it would be much harder to take off and I would run into heating issues. Gallery: Final descent. I have no roll control here so I can't land on the runway, but I can still land on the grass. Landed! If I were to attempt this mission again, which I won't, I would probably remove some air intakes as they were a pretty big fraction of my total drag. I would also add ailerons. A couple smaller optimizations would be to use the Mk0 fuel tank instead of Mk1 fuel tanks and the Big-S strake instead of the delta wing, which would reduce my dry mass. I didn't do this for part count reasons, but they would be reasonable upgrades with a more powerful computer than my laptop. A large optimization would be to reduce wing area and switch to supersonic air intakes (maybe a single shock cone or ram air intake would work). Cruise would be at Mach 2 instead of Mach 0.6 - this would increase the value of speed * lift / drag, which dictates how far you can fly on a given engine and amount of fuel. You'd need a really long takeoff run to make full use of this, and I'm told there aren't a lot of large flat areas on Earth to act as a runway. But this flight is definitely beatable.

Looks a lot like this challenge! For this one, I submitted a pair of Kerbals in quite the situation. -Retrograde Kerbol orbit -periapsis 4921 km -apoapsis 536000 km They are in a very heat resistant vessel so that shouldn't be an issue. I can DM you the save file if you want.

This is an interesting challenge. I was going to try to cheese it - the DLC turboshaft engine has a built-in alternator that scales with RPM and not with torque, and is also frictionless. Kickstart it and it provides electricity forever, like a less mass efficient RTG. My plan was to run one unit of liquid fuel through the turboshaft to charge a small battery, and then spin it with some DLC electric motors to generate electricity more. Time warp wouldn't be an issue as I could just start it from the battery again, and then I would do something interesting like a Jool surface return using ions and magic wings. However, what I discovered as I was testing crafts was that for some reason, the alternator would scale with 1/(rpm limit). I assume this was to simulate the effect of a gearbox, even though it would be perfectly backdrive-able. Apparently, when rpm limit is set to zero, alternator output hits a divide by zero and evaluates to infinity, which basically means that I've discovered an infinite electricity glitch. A clip of it is attached below. Note the change in electricity generation when I change the motor's RPM limit, and how I generate 64k electric charge in a single frame when RPM limit hits zero. Also, I'm spinning the turboshaft at 920 RPM by rotating both the base and the rotor with DLC electric motors, because I planned to do this originally to generate twice as much electricity per motor.

Discord is best for small communities in my opinion. I find it a lot easier to keep up with, for example, super-optimized stock KSP missions, because there's a pretty small group of people who actually does that and it kinda gets lost in this big of a forum.

It doesn't need to be exploity. You can do something like attaching a 1.25 meter fuel tank to the front of the fairing, or a 1.25 meter nose cone. It'll occlude just as well.

It's a Mechjeb unit because I'm not good enough of a pilot to fly this craft consistently - the ascent profile needs to be very precise with a lander this small. It doesn't really provide a benefit to the craft otherwise, in fact it just adds drag, but it's a good band-aid solution for my lack of piloting skill. I also use Mechjeb for aero and TWR info in a nice compact display, so it's not just used as an autopilot. Edit: The ascent profile is roughly as follows: -Go up to 43.5 km altitude on propellers. The propeller stage can go higher than this but it takes a really long time. -Light all engines and pitch down to 55 degrees pitch. I found that this was a good angle to get out of most of the atmosphere and also build up vertical speed. If drag weren't an issue, I would want to go closer to 30 degrees, but drag is an issue so I want to get out of the atmosphere quickly. -Drop fuel tanks as they empty. I don't draw fuel from upper stages as the engine dry mass isn't worth it. -When apoapsis reaches 65 km, lock prograde because there's enough vertical speed from the second stage. -When the second stage detaches, pitch to 30 degrees and hold it - the Spider engine has really low TWR so this is necessary. -Finally, circularize with the jetpack. I hold the translate forward and upward keys at the same time, which loses a bit of efficiency but buys time to gain horizontal speed. This is important because the jetpack also has very low TWR, so it needs a lot of centripetal force in order to maintain altitude.

Motivation For a long time, I've been interested in ultra low mass missions, and even flown a few myself. It's incredibly satisfying to iterate on a design and watch it get smaller and smaller, often beyond what I believed was possible originally. One of the most difficult challenges in stock KSP is getting a Kerbal from Eve's surface to a low Eve orbit. The high gravity, dense and unoxygenated atmosphere, and large planetary size all combine to make Eve more difficult than any other planet (with the possible exception of Jool, which doesn't really have a surface). Low mass Eve missions are very interesting - Bradley Whistance's 9 ton Eve mission was a big influence in how I play KSP. The Design Process At the beginning, I stuck to a few design principles common in low mass craft: -The craft would be controlled through a command seat. The command chair is much lighter than any command pod - not only does this reduce mass of the craft directly, it also requires less propellant to launch into orbit. However, it's not very aerodynamic, which is a bad thing when dealing with Eve's atmosphere. Fortunately, a command chair in a fairing is still much lighter than a command pod, plus the fairing can shield fuel tanks and engines from drag. So I also decided to use a fairing on the lander. -I would use a propeller to get above the majority of the atmosphere. Not only does the atmosphere present issues with drag, it also reduces the efficiency of my engines. With a propeller, not only do I incur less drag, I also start burning the rocket engines from a higher altitude (meaning I have more energy and thus use less delta-v), and the burn can be done at a higher efficiency. Note that propellers aren't the best for Kerbin because jet engines are lighter and can give a bigger speed boost, but jet engines don't work on Eve. -I also want to use the EVA pack to finish circularization. The EVA pack with the extra fuel cylinder is about 900 m/s of delta-v, which is too much to pass up and more than makes up for the additional EVA propellant mass by lowering the fuel requirement. I've divided the various iterations of the lander design into categories so there isn't a big text wall. The initial lander design is 5 tons and gets improved from there. Category 1: Ducted Fans At this point the mass of the Eve lander is 3.31 tons. This is a huge improvement, but we can do better still. Category 2: Basic Fins Category 3: Basic Fins, Part 2 Category 4: Fairingless The final result

I got a ~10 ton craft functional, but I didn't fly it beyond low Kerbin orbit. @Ultimate Steve If you're still interested, I'd love to collaborate on another grand tour!

Fuel flow has been an issue for a long time. Did you just use the exact same system as in KSP 1?

Amazing! Maybe make a leaderboard for most records? (: Jool surface can be another category. I know Brad Whistance, Stratzenblitz and Lt_Duckweed have done it before. I think Lark has also, but I don't know details.

I remember Bradley Whistance used staged batteries to make it work, also he made significant use of body lift to increase his usable thrust.

woah this challenge exists i might attempt a juno based mission

This is possible with sufficient abuse of propellers and magic wings (Stratzenblitz did it)

You should disallow action groups as well.

I actually had a serious submission in the works (very similar to OJT's most recent one) before I saw the message about root fairings, so I never finished it. I've been well. Doing some games other than KSP, but still playing. Right now in KSP I'm working on a tour of Lt_Duckweed's Quack Pack.

This challenge as-is is so ripe for exploiting that it's honestly a bit ridiculous. This seems like it's a game of who can get the closest to a 49999.9 x 49999.9 meter orbit and then who is the most patient. Also I've seen root fairings brought up here, so clearly aero exploits are on the table. I think I'm going to sidestep all the optimization of aero exploits and orbit height at once. In KSP, two parts can mutually occlude one another. Fairings, cargo bays, and engine plates can all occlude other parts, and by using two fairings or two cargo bays aligned perfectly (and I do mean perfectly; floating point errors are enough to break this), they will also mutually occlude, leaving a craft with drag of exactly zero. Engine plates are a bit easier, as when the engine plate is "closed" with a part on the bottom node, it will occlude all parts attached to its other nodes. This includes fairings and cargo bays, both of which can occlude the engine plate. This doesn't require precise alignment so it's much more robust, although a bit heavier. I think you can see where this is going. I'm too lazy to take this thing to Duna, and it doesn't deserve an actual rocket. So here's a proof of concept where I complete an entire orbit of Duna with exactly zero drag after I decouple the rocket engine. Any change in apoapsis and periapsis is entirely up to floating-point errors, so this truly is only limited by the stability of my computer. If I wanted to really abuse this, I would leave my laptop running for several days and use a macro to quicksave every few hours, so it could persist through crashes. I don't intend this to be an actual submission. Rather, I want to call attention to the fact that submissions here aren't really in the spirit of winged aircraft range. I have a few ideas for modifications to the rules: -Start from a stationary point on Duna's surface. It could be standardized to a certain lat/long, or maybe we could be free to select our favorite mountain peak or something. -Start the distance meter when altitude crosses X amount from above. This is abuseable with my above video, but you can easily say something like "at least one wing part needs to be producing drag at all times" so our planes have to actually be planes. -Disallow fairings, cargo bays, and engine plates. This is the lazy solution and it'll still degenerate the challenge into who can get the closest to space without actually being in it.

227160 funds with tank, 175960 funds without tank, 611 funds per ton of payload. First stage is 7 Clydesdale Second stage is 1 Rhino (4x Poodle is probably even cheaper) In testing I managed to bring a few more tons of payload to orbit with a better ascent profile, but this is still pretty good

Ok, this is probably as optimized as I can get my previous expendable launcher. 287520 funds with fuel tank, 236320 funds without fuel tank. This is just about the lowest that I thought this design could go. Six Clydesdales, seven Twin-Boars, the outer six are dropped once suborbital and the central one circularizes. Warped to the day side, showing propellant and full fuel tank. Counting the bit of unused propellant as payload, this craft brings 293 tons of payload into orbit for 236320 funds, for 806 funds per ton. This is probably beatable by switching engine types, which I will attempt.

I'm gonna put this placeholder submission here, I've since done better than this but I am not quite finished optimizing it yet. I know that SRB + Twin Boar is a good cost per ton combination. Not sure what the best ratio of solid to liquid fuel is however. The cost of the S4-512 is 51200 funds so the cost of the launcher is 292310 funds. Note the lack of nose cones. Large rockets don't need them as much because of the higher thrust. Launch, immediately pitch over Core throttles down otherwise it'll go too fast in the lower atmosphere SRB burnout, apoapsis is above 70 km SRB separation Circularization In orbit. Note that I actually have more than a full Twin-Boar's worth of fuel left here.