GoSlash27

Vector addition for transfer burns crossing SoI boundaries. DV= sqrt(Vxs^2+Vesc^2)-Vorb I use this one constantly for mission planning. Vxs is the DV required to set up an intercept, neglecting the current gravity well. Vesc is the escape velocity from the current gravity well... which happens to be your orbital velocity times sqrt(2). Vorb is your orbital velocity in the current gravity well. This can be concatenated (chained) to calculate transfers from a moon about one planet to a moon about a completely different planet. Also, gate orbits. r=2GM/Vxs^2 Handy for figuring out the optimal transfer altitudes (not always LKO). Best, -Slashy

I use little drones called "hands" for my orbital assembly work. A drone core, RCS tank/ thrusters, and docking ports at both ends. Latch on to the section, remove it from the delivery stage. Grab the other end with the other hand, maneuver it into place, Move the first hand out of the way and dock the section with the other. Best, -Slashy

An old design I had laying around: 100 kerbals, 62.21t= .622 points. Super-easy to operate, too. I made it to participate in a very silly challenge; How many kerbals can you stuff into the old tower. Best, -Slashy

The reason planes are more difficult in KSP has already been explained. The reason it's the opposite from real life is the DV to orbit. It's only 3.2 km/sec in KSP, but over 9km/sec in real life. Best, -Slashy

Oh, that's fine. I'm just posting cheap designs that I didn't develop in the last challenge. These ones aren't as cheap as those, but I figure there's no point in resubmitting those since they still work. Best, -Slashy

Jason, Yeah, you're right. I don't need the nose cones or the fins, but I do need the tanks. It's just a lifter I had laying around and figured I'd submit it since nobody else had entered yet. Best, -Slashy

A new entry at the "cheap and light" end of stock. 17.2t at $891.28 per tonne. I did not optimize this one, so there's lots of room for improvement. http://s52.photobucket.com/user/GoSlash27/slideshow/KSP/Cheep17 Best, -Slashy

@Geschosskopf, The Oberth effect is not hard to understand if you look at it logically: It does not exist. It is merely a construct to help explain why you are not seeing the results you expect to see. It's like the Doppler Effect; the train moving toward you doesn't actually raise it's horn's frequency, just as the Oberth Effect doesn't actually give you free DV. It just *seems* that way because orbits don't work like we implicitly expect them to work. Every orbit exists because the object carries energy. Mostly kinetic at periapsis and mostly potential at apoapsis, but always the same total energy. You get to where you're going not because you have velocity, but because you have energy. Going back to high school physics, the kinetic energy of an object is directly proportional to it's mass, and directly proportional to the square of it's velocity. The relationship between energy and velocity is not linear, but rather exponential. We tend to think of it as linear simply because everything we do is measured in DV, but that is incorrect and that's why the Obert Effect seems to exist (and why you are able to "cheat" DV maps if you play your cards right). A fixed change in velocity adds more kinetic energy to an orbit at higher velocities than lower velocities. This is simple to prove mathematically. Let kinetic energy equal k(constant)v^2 Our change in energy in response to a change in velocity is therefore k(v+delta)^2-kv^2 We can ignore "k" since it's equal in both. Foiling out (v+delta)^2 yields v^2+2vdelta+delta^2-v^2. Cancelling the v^2 leaves 2vdelta+delta^2 The delta is common to both arbitrary examples, yet that "2vdelta" remains. *That's* where your "Oberth Effect" is coming from. Accordingly, the same change in velocity makes a different change in apoapsis depending on how fast you're going at the moment of burn. Same goes for any Hohmann transfer, or even interplanetary intercept (which is really just a Hohmann transfer that extends beyond the SoI). If you're moving quickly, your DV has a larger effect on the apoapsis. If you're moving slowly, it has less effect. It has nothing to do with what engine you use, or the mass of it's exhaust, or any of that stuff. It is simply math behaving as it ought. Accordingly, it does not need to be modeled or accounted for in the game engine. So long as we follow Newtonian physics, it will appear on its own like it's supposed to. But remember: It doesn't actually exist. It's just an illusion you *think* you see because physics doesn't work quite like what you expect. HTHs, -Slashy PS Don't argue orbital mechanics with OhioBob. He's right. *edit* Ninja'd...

Okay. This isn't the cheapest ride to orbit I've ever made, but it's the largest so far. 318 tonnes to orbit for $739.10 per tonne. All stock (no mods). http://s52.photobucket.com/user/GoSlash27/slideshow/KSP/BigCheep113 If I can swing it, I'll submit some cheaper entries at less- insane payloads. Best, -Slashy

Norcalplanner, I really don't think I'm capable of doing any better than I did in the 1.0.3 challenge, but I'll see what I can come up with. Maybe something ridiculously huge... Best, -Slashy

I think it's extremely silly that we don't have props already. There are plenty of good add- ons available. Best, -Slashy

I concur with most of the above suggestions. While I am able to use the lumpy runway without any problems, it's silly to have a lumpy runway. Flatten it and make everything around it lumpy! Best, -Slashy

Ah, here it is. NovaSilsko's comments on the subject: Best, -Slashy

I like this idea for interplanetary motherships where I'm aerobraking at both ends. I currently have to leave the shield inflated. Previously, I replaced the ablators in orbit during refit/ refueling using clamp-o-trons. It'd be nice to be able to stow them when not in use. Best, -Slashy

IIRC... But of course none of this was ever implemented, so now we just have the leftover clues as easter eggs. Best, -Slashy

I was wondering about that myself. Why not just build a big SSTO and call the whole thing "payload"? x mass/(launch parts-payload parts)= x mass/0 =infinity points. Also, I didn't discount my payload parts from my entry. Corrected, my score should be 4.6. Best, -Slashy

LN400, When speaking of first stage DV, I calculate it at 1/2 ATM. Everything else is vacuum. Best, -Slashy

And FWIW, I've found that even with my "cheap" lifters (which follow a true gravity turn), I find substantial DV savings by following an aggressive trajectory like you demonstrate here. I necessarily have to hit a higher speed before the kick, but the path winds up being the same. Best, -Slashy

RIC, I haven't, since none of the gate altitudes exceed the Mun and other assorted difficulties involved with departing from Minmus. I can run them if you like and get back to you on it. Best, -Slashy

magnemoe, Surprisingly, most destinations actually wind up costing more DV if you drop all the way back down before transfer. That's the weird balance between Oberth and the gravity well. Every destination has an ideal periapsis to depart from, and this ideal altitude is somewhere higher than LKO. I ginned up a handy list. Hang on, I'll see if I can find it... (rummaging noises...) Ah, yes. Here we are (adjusts glasses, clears throat) Moho: Periapsis 680 km Eve: Depart directly from Mun Duna: Depart directly from Mun Dres: Periapsis 1 Mm Jool: Periapsis 360 km Eeloo: Periapsis 210 km Best, -Slashy

nascarlaser, The ideal rocket will depend on exactly how much mass you're taking up. Could be anywhere from 2.1 to 4.3 tonnes, depending on which option you choose. 2.1 tonnes is a Skipper with 1 X200-8 and 1 X200-32. 4.3 tonnes is the same with an additional X200-16. Best, -Slashy

nascarlaser1, We were discussing designs and popularity earlier? If you can isolate and harness that kraken drive you've inadvertently created, it will be the most popular download on the forum. Best, -Slashy

haha you're just catching on? -Slashy

Norcalplanner, Thanks for the valuable data! I think we figured out back in 1.0 that the cheapest trip to orbit (in terms of DV) was high t/w, a large rocket, and aiming the gravity turn so that circularization occurs at 43 km. Of course... getting to orbit with the lowest DV expenditure isn't a practical concern. At least not in career. What matters most is getting to orbit cheaply. That generally requires much lower t/w. Best, -Slashy

RIC, If you set up an infrastructure so that you have a refueling station in LMO, trips to every destination in the system are cheaper than direct burns from LKO. Closer planets get a single burn from LMO, while farther destinations get 2 burns; first to gate periapsis and second to transfer. This makes the IP vehicle much smaller and more efficient, reducing costs (both in DV and dollars). I just pointed this out to counter the notion that direct transfers from LKO are always cheapest because Oberth. They are not. Oberth doesn't always win out over the gravity well and it's useful to know when it does and when it doesn't. You could be right though; most IP trips probably are single launch. My mileage varies because I never do single launch IP trips. Best, -Slashy