Francesco

yeah, the cool thing about Kerbin is that you can turn on LV-Ns pretty much right away: at 1km, their ISP is already ~330 (versus 220 at sea level), so it's on par with the other engines, and therefore they cease to be dead weight just a bit after takeoff. sadly, on eve we can't take advantage of this. :/ but I'm curious, is there actually an advantage on using wings to generate lift on Eve? I'm talking stock parts, without FAR.

dat picture I guess I should have phrased it better. there's no doubt that periapsis kicks is the best "technique" here, I was just noticing that for all the burns following the first one, your altitude is going to change quite a bit during the burn itself, compared to the first kick (which you perform starting from a circular orbit.) but then, it's not really the altitude per se that matters, but rather your velocity, right? so during the subsequent burns, coming towards periapsis, you're gonna be more efficient as you're travelling faster. so yeah, let's just pretend I didn't say that to begin with what about this, RoboRay: what's your rule of thumb for PE kicks - how long does each one last, at the most?

a couple of things about this challenge: 1. I guess the no launch clamps thing is to avoid people exploiting that to get free delta-v by placing their ship as high as possible, but it leads to some problems, like the ship standing on engine nozzles (not a very nice thing to do, especially with NERVAs). this is what I had to come up with to provide a safe and stable platform: 2. but that of course increases the part count, going well past 40. besides, I don't get why there is a part count maximum to partecipate in this challenge. it would make more sense to just give more points to those who use less parts, but not as a strict rule. 3. it seems that it takes 2.7-2.8 km/s to reach Sun escape from LKO, so a total delta-v of 7+ km/s is required; that's really pushing it in engineering terms, since most engines in KSP have a max mass ratio of 8-8.5 km/s; even by adding LV-Ns and raising that limit, we also have to consider a lower launch TWR as we add more fuel tanks, which is a problem since we're talking about a SSTO here and we can't discard SRBs/boosters. a cousin of that ship in the pic came several hundreds m/s short of achieving solar escape: maybe it could do better with some tweaks, or maybe an air breathing hybrid is the way to go - but again, that would require more than 40 parts.

although a thing I should add, which I haven't seen mentioned yet, is that by doing periapsis kicks, for every kick after the first one, you're going to be burning quite higher than the typical 70-80km LKO: coming in towards periapsis, you'll be as close as you can to Kerbin (which is what you want to take advantage of good ol' Oberth effect) for quite a short time. so this kinda mitigates the efficiency of the maneuver, but it's still the best course of action anyway.

if you're patient, once you are in LKO, TWR doesn't really matter: with a 0.1 or 0.2 TWR, you can do a series of periapsis kicks. most delta-v intesive destinations: depends on whether you plan to simply get in orbit around them, land on them, or land and get back to Kerbin from them. in general, I would say they are Moho, Tylo, and Eeloo, with Dres as a runner-up.

eve return should be like 20x points

must have: kerbal engineer (you are what you build ), maneuver node improvement (so simple, yet so useful) should definitely have: subassembly loader recommended: protractor, mechjeb, crew manifest, hyperedit

yup, but it's usually too annoying for me to do that: I mean, it's cool to transfer your Kerbals from the runway to the launchpad for two or three times - it adds to the experience of the game - but then, you'll likely prefer to bypass the problem entirely and use crew manifest http://kerbalspaceprogram.com/18-1-kerbal-crew-manifest/

that graph is meant to show that it's impossible to build an Eve SSTO with more than ~8500 m/s of delta-v. edit: I agree that by combining, say, aerospikes with LV-N's (which you would switch on later during the flight) you could in theory achieve a higher delta-v, but you would also have to carry them as dead weight (because of their low sea level ISP) for quite a long time during the launch.

clear sky yeah it could even be Jool, how can you be so sure it's Minmus?

no again. that's not a bi-elliptic transfer. there is no point in terms of efficiency in what you are saying: to go from a 80km orbit to a 200km one, you just do a simple Hohmann transfer: to take advantage of the Oberth effect, you burn lower, at 80km, not at 100km. raising your AP first to 100km and then, from there, to 200km, will cost you more in terms of delta-v. but we're digressing here: what the OP was asking is what Temstar said, Direct injection/ejection. as already stated, that maneuver is more efficient, but also more challenging to accomplish. a real word example of this is: http://en.wikipedia.org/wiki/Chang%27e_2#Lunar_mission

I don't always troll on the KSP forums... ...you seem to have some confusing ideas there: what's this "burn at orbit B" anyway? you burn at B to go to C, it's not like first you circularize and then you do another burn. so it's only 3. and you don't burn as low as possible: in fact, when you are at "B", you are as high as possible in the gravity well, since "B" is your Apoapsis.

yup. thanks to Google Cache I've found this chart, posted some time ago before the forum shutdown: it clearly shows what foamyesque is saying.

nope, Hohmann is 2 burns, bi-elliptic is 3

actually, there are some situations where a Hohmann transfer is less efficient than a bi-elliptical transfer. so, no.

Oberth, Hohmann, Hoffman (?)... we're messing with German surnames here but yes, everything has already been explained. to make it really simple: straight to Kerbin escape = more efficient, LKO insertion first = easier for you.

you're right in saying it's your personal opinion: SRB actually have a pretty high TWR in this game - try putting a probe on top of RT-10, fire it and you'll see. besides, that is not a fair comparison. SRB are pre-built, while you can build liquid fuel boosters of any size and thrust.

I put panels inside ya panels so you can... oh wait.

well every orbit drifts, in real life; in KSP, I was only aware of this phenomenon as due to the use of time warp, and sometimes randomly happening as you maneuver your ship. so you're saying this also happens while playing in real time, by actually doing nothing?

exactly, periapsis kicks. just to be totally clear, it's not 30% and 70%: it's 3/7 (roughly 43%), which is just a fancy way of saying, "less than half" (of the estimated burn time.)

really? why does this happen?

you need to define "heavy lifter" in terms of the weight of the payload. what is it, 50 tons? also, 50 tons to orbit or 50 tons landed on the Mun? "2 red tanks" and stuff doesn't mean anything by itself: to give an accurate description of you lifter, you should also tell which engines you are using.

nice! you still can escape Sun's gravity, by using Jool to perform a slingshot maneuver.

I like to have a TWR of 0.5-0.6 when using LV-N engines: that way, I can usually fractionate long escape burns (1.6-2 km/s) in two parts. but that's just my preference. in general, you don't want to burn for more than 3 or 4 minutes - that is, for more than 2 minutes before and after your ejection angle. also, I find the 50/50 rule to be quite imprecise: if you create a maneuver node and look at the expected burn time, you'll see that it slowly decreases from its original value; that's because as you burn fuel, the TWR of your ship rises. so, I like the "3/7" rule better: given an estimated burn time per the maneuver nodes, I'll start burning at 3/7 of that time before T+, and put the remaining 4/7 after. note that this applies more specifically to long burns (e.g., Kerbin escape) as opposed to short, correction burns (e.g., inclination changes)

ladies and gentlemen! today, on the KSP forums, another thread degenerated into a flame war