vyznev

Well, I guess this old mission earns me 2×500 points, then. (Actually I guess that's 2×505 points, since it looks like I reached the eccentricity target too.) (Not 100% sure about the settings, but your list mostly matches what I usually play with. Part upgrades might be the exception, but I don't think they'd have made any significant difference even if I had them on. And I'm not sure about the Commnet settings either, but both vessels were crewed so it definitely wouldn't have mattered.)

Nice video. And yes, that indeed also works with the bike I built, and does let you turn a lot faster than just leaning over would. It can feel a bit wobbly sometimes, though, but I suspect that's in part due to the limited fine control provided by the keyboard controls. It might behave a lot better with a proper driving controller, but I don't have one to test it with. Still, even with a keyboard, the bike is actually quite stable and only rarely flips over.

Very nice! That design also looks rather hard to beat. I do see a few potential ways to maybe shave off a few kg here and there, but nothing that would make the result look significantly different from yours. Maybe if I used an SRB…

Does the shuttle need to be crewed? And does it need to be able to carry a payload (and if yes, how much)?

The runway landing, of course. I suspect somebody in the control tower needs a change of pants after that. The Mun landing looked pretty routine in comparison.

Impressive! That was a very… kerbal landing. Nice craft, too.

Here's the same principle applied to an actual replica (minus a bunch of bells and whistles equipment and science instruments): As you can see, it's not quite there yet as far as looks are concerned. But all the mechanically important parts work.

Looks like that's true for the non-exploit method too. I added a fuel tank as ballast to the launcher from my previous post and got a whopping 451 meters of extra altitude. (Waiting until the tip of the launcher was pointing more precisely straight up might've helped a bit too, as the piston stack is tall enough to wobble a bit on the launch pad. I might have to consider adding some extra throwaway bracing struts.)

That's really neat! After downloading the craft and studying a bit, I think I mostly get how it works. The one thing I'm still puzzled about is how you seem to have managed to keep the rotors that the cubes attach to from getting gimbal locked. I tried looking inside, but all I see is an octagonal strut crammed full of rotors clipped into each other, and trying to pull them apart wasn't very helpful either. Sometimes it would be really nice to have some way of selecting a part in the editor and having it highlight (or even switch to) that part's parent. Just saying…

The launchpad surface is 72 meters above sea level. (Yes, I just checked. The wiki says 68 meters, but I think that's for the level 1 launch pad in Career mode.) But if we're being completely fair, we should also subtract the height of the piston stack, which is about 45 meters tall, for a total starting altitude of 117 meters ASL. Which, in fact, is what the pre-launch screenshot shows. (I wasn't sure if it was showing the altitude of the root part or of the center of mass, but apparently it's the former.)

Clearly you're just not using enough pistons. Craft file here: https://pastebin.com/5zjhZ4q9 Note the complete absence of any KAL-1000 controllers. I did "cheat" a bit by leaving the pistons on the ground instead of launching them with the craft, but you didn't say I couldn't.

While testing a simple Mars rover replica with wheels built out of Breaking Ground rotors and grip pads for a challenge, I noticed that it could ski indefinitely in a circle with just the wheels on one side in contact with the ground. Of course, this immediately suggested the possibility of building a Kerbal motorcycle. The result is what you see here. (In case you're wondering, the Mk1 was basically the same thing but with worse wheels.) I'm positively surprised by how well the makeshift wheels work. It seems that radially attached BG grip pads really do make a pretty good substitute for rubber tires. Notably, there's no suspension on the bike, but the wheels flex under pressure and provide a natural cushioning effect. The rear wheel does noticeably expand while driving, even though I applied rigid attachment on the pads. Clearly "rigid attachment" in KSP does not mean perfectly rigid, just a bit more rigid than usual. I designed this thing to work and behave as much like a real motorcycle as possible. Like on a real motorbike, you mostly steer by shifting your weight — in this case, via the roll controls, which are bound to a hinge that moves and tilts the command seat(!). Yaw (actually wheel steer) controls the steering column and is best applied sparingly, as it tends to cause strong adverse roll. The bike is reasonably stable and driveable even without SAS, especially at low speed (around 10 m/s or so seems optimal for stability). It goes up to 25 m/s or so at full throttle, although that's definitely straining the wheels a little. At higher speeds, if things feel too wobbly, turning SAS on can help — while it won’t affect the steering much (since that’s done mainly via the hinges, which SAS won’t actually control), there’s a small reaction wheel set to SAS only buried in the body that can help in damping out oscillations. You can think of that reaction wheel as modeling the driver's (otherwise all but nonexistent) natural weight shifting to maintain balance. Or, if you consider it cheating, just turn SAS off and drive without it. At launch, stage to start the engine, throttle up and press G to raise the landing legs. To stop, throttle down and extend the legs before you fall over. If you do fall, it’s usually possible to get back up by deploying the legs and briefly toggling the throttle (which should cause the bike to flip over!). Or you can just get off and push. If you find yourself needing pitch control in midair (because of course you will ), consider using the throttle — that rear wheel can carry quite a lot of angular momentum. On the same token, hitting the brakes at high speed is not advised. Specifications: Part count: 177 (most of them grip pads ) Height: 2.0 m Width: 2.7 m (with the "kick stands" extended) Length: 4.6 m Mass: 1.66 t Carries: one kerbal in a command seat (no probe core) Craft file on KerbalX: https://kerbalx.com/vyznev/Kerley-Davidson-Mk2 (I finally made a KerbalX account just so I could post this there!)

There's an RTG that you can see poking out of the rover body. The RoveMate body itself can store 120 units of power, so no separate batteries are needed. In practice, it seems that the BG motors are pretty power-efficient (and RTGs in KSP are, of course, unrealistically good). I've never noticed the stored charge dropping below max, even when running at top speed (which, for this particular rover, is around 7—10 m/s; beyond that the wheels start to get wonky), so apparently the single RTG is enough to satisfy their power draw.

So, after thinking about this a little, I decided to try building a rover with a working rocker-bogie suspension as a proof of concept: It's all built with BG robotics parts, no stock wheels. The only powered parts are the wheel rotors and the two servos at the front used for steering. (I believe Perseverance uses four wheel steering, but I was lazy and only made two of the six wheel steerable for this test rover.) The real secret ingredient is the unpowered servo at the back of the rover body and the two grip pads attached to it, highlighted in the screenshot above. The grip pads have same-vessel interactions turned on, as do the four pads on the suspension that they're sandwiched between. What this simple mechanism does is implement the rocker part of the rocker-bogie suspension: it holds the pitch of the rover body at the average of the pitches of the two upper suspension arms on either side of it, thus allowing the body to match the approximate tilt of the terrain below it, even when said terrain is highly uneven: Craft file here: https://pastebin.com/LV6crxNq

Part of the reason for the limited interest might be that the difficulty curve feels kind of wonky. What I mean by that is that it's really easy to build something that kinda looks a bit like Perseverance, because KSP has a lot of similar looking stock / DLC parts built in. But for the parts that don't have decent stock look-alikes in KSP, building decent replicas of them gets really hard real quick. Especially if you don't (heavily over)use Tweakscale. Take the wheels, for example. KSP of course has the Ruggedized Vehicular Wheels that look kinda similar to the ones on Perseverance, and if you just stick six of them on the rover, it'll look kinda like Perseverance from a distance. But if you try to actually recreate the rocker-bogie suspension and the cool-looking way the wheels attach to it… well, there just isn't anything like that in KSP, so about the only way would be to try to build the wheels and suspension yourself out of Breaking Ground robotics parts. Which might be doable, and making it work could actually be an interesting engineering challenge. But making it work and look authentic seems really hard. Especially if you want the rocker mechanism to actually work and tilt the rover body like it's supposed to. Also, except for the Ingenuity drone helicopter, the Perseverance rover looks a lot like Curiosity. So I'd guess a lot of the people who might be interested in doing this have basically done it already. Anyway, I figured the drone seemed kinda interesting, so I tried building a simple replica. Basically, what I wanted to test was whether I could hide the big ugly Breaking Ground rotors by clipping them inside the drone body. And it turns out I can. I'm kind of annoyed that I had to include a reaction wheel, but it was the only way I could get useful yaw control. In principle, it should be possible to control yaw just via differential throttle on the two rotors, but in practice stock KSP doesn't seem smart enough to do that. (Wouldn't be hard to write a kOS script to do it, though.) And yes, it does fly. Not very long on just one battery, but then, neither does the real thing. Peak altitude on Duna is somewhere between 1.5 km and 2 km above datum, so better not land on a mountain. I could probably save a bit of weight and improve performance by reducing the motor size — 30% torque seems more than enough to max out the RPM limit even with a high blade pitch.

What about the in-game difficulty settings? Those affect science (and money) rewards, don't they? Is it just orthogonal to the challenge difficulty?

Perhaps. But I wanted to see how it flies without it. And to be honest, KSP's SAS isn't all that great when it comes to flying planes. For one thing, it doesn't allow trimming the controls while it's active, so you can't tell it to e.g. "hold prograde but pitch up by this much." It's also not very good at making gradual turns — even in fine-tuning mode, its steering tends to be a bit jerky. In my experience, most of the time, if a plane is stable enough to fly without SAS, it often actually flies better without it, once properly trimmed. (For the specific task of "hold prograde but pitch up by this much" there is a workaround, but it involves using DLC parts. Basically you put a probe core or a docking port on a robotics hinge and control the vessel from there. You can even map the hinge angle to some unused control axis like "translate up/down" so you can adjust it without right-clicking the part. But it doesn't help with the other issues of flying planes with stock SAS, and of course you have to build that feature into the craft — it doesn't just work with any random plane downloaded off KerbalX.)

Well, I'm on PC (Mac, actually), so I flew it for you. Consider this an unofficial extension of my "bad plane flight test" series. Anyway, the answer seems to be "surprisingly well". Takeoff was kind of wiggly, but I'm positively surprised that it didn't crash on the runway. And once I got it aloft and properly trimmed, it wasn't bad at all.

So how does that work, anyway? Is it just a weird electric rover using reaction wheels, or is it actually powered by some kind of kraken tech?

Technically, I could do a bielliptic plane change followed by aerobraking without ever raising my periapsis above 70 km. But I guess the second part rules that out.

Good point. I'm more used to doing these kinds of maneuvers around airless moons, where that's more difficult. Anyway, whether aerobraking is allowed or not, I'd still like to see an altitude limit of some kind. I guess something like "periapsis > 70 km, apoapsis < 250 km" (which matches the in-game definition of "in space low over Kerbin") would make a reasonable default if you don't want to be stricter.

Can we get a definition of what counts as LKO, please? Specifically, what's the highest allowed apoapsis? I ask because I'm pretty sure the way to do this with minimal delta-v is either with a bi-elliptic transfer or a gravity assist off the Mun or Minmus — both of which will first put you into a highly eccentric equatorial orbit that you then need to circularize with a retrograde burn at periapsis, and the shorter that burn can be, the less delta-v you'll need. (Also, is using 1.8 + HyperEdit / VesselMover allowed?)

Well, that was unexpected. And your entry does indeed appear to be perfectly valid under the challenge rules, too. I'm not 100% sure whether to just give you first place in the general category or to start a whole new category for fully automated craft. I guess I'll put you in general for now, and think about possible new categories if and when more robotic entries show up. (I'm also wondering, if I do make a new category, whether I should allow kOS in it.) In any case, thanks for the awesome entry, and congratulations on taking first place!

I still haven't flown the mission, but instead I ended up rebuilding my lander from scratch because I wanted it to look nicer. I feel like this is starting to look pretty close to the renderings. (Also, the actual structural linkages are now much less janky, since this time I actually had some idea of where I was going when I started building this version.) I did fly a couple of test hops at KSC, since this thing actually has enough thrust for it. Like @jinnantonix's version, this one also has some difficulties with attitude and horizontal speed control. I might need to add a few more RCS ports. (The renderings actually show a pair of RCS nozzles above the crew compartment that I haven't included so far.) Landing in full Kerbin gravity can get a bit rough, but at least the core structure is surprisingly durable.

I'm also working on a Dynetics-style lander.