maccollo

Sunset/Sunrise tint also happens in orbit =O

I'm not sure any engine would be good for a saturn V replica in stock. The problem is that, given the overall performance of stock parts, the delta V requirements for a mun round trip is to low, so a replica that looks good will be over-engineered for the task. Here's a replica that can perform a mission to mun in an Apollo like mission plan. The proportions of the rocket is roughly correct, the initial TWR quite close to the real deal... but it's built for a 4X kerbol system where the ratio between max stage deltaV, and deltaV to orbit is a lot closer to real life than it is in stock. This means you end up with fairly realistic rocket designs using stock parts. So a 3 stage booster to land 2 kerbals on the moon is actually quite optimal, and even though it is 4X scale there's enough margin to add science payloads to the lander.

No. It's just a retrograde orbit. Altough it's just outside the hill sphere of Mun it's still stable. This is a neat characteristic of retrograde orbits. Anyway, I've made sure there is enough deltaV on the cargo vessel to perform the rendezvous. The native patched conics trajectory will be highly inaccurate, though that's sort of the point. The real trajectory makes a lot more sense when you actually see it in motion.

Seeing as Principia is getting to the point where it is quite useable, it seems to be a good time to do this. The challenge is fairly straight forward. A space station has been placed in a magical square orbit around Mun. The objective is to pilot the cargo vessel, which is in low Kerbin orbit, and rendezvous with the station, using as little delta V as possible. You will need a 1.2.2 installation of KSP with a stock planetary setup, and Principia Catalan, then load this save file. https://www.dropbox.com/s/d9vbdw0wba0jkxv/rendezvous.zip Rules: No use of cheats or performance altering mods. Telemetry and visual enhancement mods are allowed. Since this is not a docking challenge, you only have to park within a 100 meter distance from the station, with a relative velocity less than 0.3 m/s. Submissions are scored based on how much delta V remains after rendezvous is complete. The Kerbals must not exit the station. Also crashing into the station to slow down is not allowed The time limit is 5 Kerbin years. This is just a technicality since I can't be certain the orbit of the station will be stable 1000 years from now. This is not a super serious challenge so extensive documentation is not really required. Just post an screenshot showing your overall approach, and one after you've completed the challenge showing how much delta V you have left. However, feel free to show your approach in greater detail if you complete the challenge with a small amount of delta V.

It's a known issue that they have fixed for the next release. For now you can fix it by using the debug menu (Alt+F12) -> console -> input locks -> clear input locks.

The planets simulate at much lower rate that vessels, so if you disable asteroids you can simulate 1000 years in 2 or 3 minutes with the stock system. If you add more stuff it will obviously be slower, but you shouldn't have to wait hours.

Submission for category 1. Same old sustainer, except this time I used the offset stack trick to reduce the drag on the boosters. As a result I was able to push it below 600 funds/ton. booster cost: 36488 funds Payload: 61.87 tons 589.8 funds/ton

Pretty sure this will the the worst on the scoreboard: 49.637 tons. However, I wanted to see if I could do it with a standard rocket, and so I didn't use xenon, air breathing engines, or command seats, just a standard 3 stage rocket with the second being an LV-N stage.

You need the version that's in the master zip file on github. There's a folder in it called output, and in there you will have a version that works with 1.2.

They are Reliants, which is why I had to add those fins. There were some balance changes in 1.2 which appears to widen the performance gap between the two when used as booster engines. Also, the spark got a 11% increase in thrust, and also a very significant 20 second increase in vacuum ISP.

Did the challenge with an all chemical rocket with a mass of 28.43 tons. Like @Aegolius13 I also didn't use a heatshield for Kerbin EDL, and instead opted for multiple aerobrake passes.

The gateway orbit, which would be at about 4000 km above Mars, will only lower the round trip delta V from 4000 to 3600, while the elliptical orbit approach will lower it to less than 1600 m/s... If it is executed correctly, and it might be more on some windows since Mars is like Moho when it comes to consistency in transfer windows. The MAV would need 1 km/s to reach the gateway orbit from LEO, compared to 1.35 km/s to reach the ERV in a highly elliptical orbit. Principia is quite stable now. I tested it quite a bit by running it doing a career run with it, and it works quite well. n-body orbits only gets really tricky when you are dealing with low energy trajectories, but for the most part you don't actually use those. Orbit that are set firmly inside a gravity well don't suddenly go crazy, and the flight planner allows you to predict years into the future. As an example, here is a rough flight plan starting from getting captured into an eliptical orbit, all the way back to Earth using 1 km/s of deltaV. It's not quite as efficient as it could be. The flight planner is a bit awkward for these multiple maneuver plans, but it is still sort of manageable. http://imgur.com/a/ApwVL To plan more generally for transfer windows and such, I'm not sure the regular transfer planner is going to be accurate, I've been using this one that was made for orbiter. http://www.orbithangar.com/searchid.php?ID=5034

Well, there is principia. Weak boundry can be quite tricky, but this one is very easy. Simply burn to get captured. Right as you cross into a captured orbit, the trajectory will end up looking like this, so you only have the do the burn to get kicked down into an elitpica trajectory again, which should be about 175-200 m/s, so you save a couple of 100 m/s compared to doing the same maneuver with patched conics.

Just tested one of my designs, which has a high thrust first stage followed by a low TWR upper stage, and it looses 60% of it's payload capacity to Kerbin escape velocity.

But it's impulse/cost ratio is garbage. You get 8448 Ns per fund. Jump just one step up to the hammer, and you get 13450 Ns per fund, and the kickback gets 15584.

SpaceY entry booster cost: 17600 funds payload mass: 31.42 tons cost per unit of payload mass: 560.15 funds/ton

Found a very good combination using the big KW Thor II solids and the Maverick-V. The Maverick brings the cost down quite a bit. 2650 funds for 1400 kN of thrust at an ISP of 315. That's about half the cost of a skipper. It's insanely good! (Though not quite good enough to replace the solids). Comparing the Thor II to the kick back, Thor II has 20% higher cost per impulse, 15% higher cost per unit of thrust. However, it's structural mass fraction is much better, 7.5% compared to 18.75% for the kickback, so more of the impulse will actually go into the core. Not sure which one actually comes out on top, but one Thor II is certainly a lot less unwieldy than clustering 5 kickbacks together. booster cost: 52820 funds payload mass: 97.01 tons cost per unit of payload mass: 544.5 funds/ton To be frank, the cost balance in KW rocketry is a bit broken.

Alright then, this allows me to beat my personal record with ease KW rocketry has slightly different cost charateristics. The fuel tanks and more expensive, but have slightly better fuel fraction, while the engines cheaper but have slightly worse performance. Overall it seems cost difference is more significant than the performance for launches to low orbit, so mixing stock tanks with KW rocketry engines seems to be a good idea. With that, here is my entry... It's another kickback boosted sustainer. Shocking! The core engine is the Vesta VR-9D from KW rocketry. booster cost: 27820 funds payload mass: 47.27 tons cost per unit of payload mass: 588.5 funds/ton

are mixed parts allowed, like using both stock parts and KW rocketry in one launcher?.

Finished a KOS launch script for SLS that I have been working on.

Performances a rendezvous with Principia at the Kerbin Mun L5 point, where I had placed a Space Station. I've managed before with Hohmann transfer, but this time I tried to use a more efficient route.

It seems Jetski set a president. Still, what's the criteria for for the score? Launch mass? Cost? Mission time? Anyway, here's my entry. Went somewhat overboard with the editing, and actually spent more time doing that than actually flying the mission.

Seems doable, but the rules require some clarification. Is it enough to simply pass through the SOI of Eeloo, or do you have to be in orbit? If so how low an orbit? Or do we have to land as well?

Pretty much never since I always run them at max thrust. edit High thrust/cost ratio is one of the advantages of solids. Reducing thrust doesn't seem to make sense. If I have more power than I need, then I balance that by switching to a weaker engine on the core, or by piling on more liquid fuel.

Refined my trebuchet a bit, making the flexible segment longer. Managed to throw the kerbal 1.5 km.