GoSlash27

Vashts, 1:1 is plenty for series mounted intakes. In truth, most intakes are more than you need to feed an engine. Best, -Slashy

I wouldn't be opposed to community reworking of the stock craft, but remember what their function is. Stock craft are supposed to look good on paper, but have a major flaw that hinders them. This gives the user an opportunity to troubleshoot them and learn about aerospace engineering principles in the process. If they work well out of the box, it's a disincentive to learn. Best, -Slashy

All of the above. The focus is now on eliminating drag. The cleaner your design the less engines you need to get it up to ludicrous speed. -Build it so it looks fast and it probably will be. Think needle shapes without blocky junk hanging out in the breeze. -And don't be afraid to use wings. Wings generate a lot less drag to generate lift than fuselages. -Build it so the nose is pointed as close to prograde as possible during the flight. The closer the better. -Intake spamming will only hurt you. Just give it enough intake to stay lit up to 23 km or so. If you can get it past about 360 m/sec then it will be capable of exceeding 1 km/sec and possibly as much as 1600 m/sec depending on how it's built. So get it up to 18km and get all the speed out of air- breathing mode you can while you drift up over 20km. Then engage closed cycle and proceed like any other rocket. SSTO spaceplanes are a little more difficult than they used to be, but not all that much. If you can figure them out they're still way more economical than chemical rockets. Good luck! -Slashy

JackBush, Are you executing the circularization in map mode? That helps a lot. I maintain the time to Ap at least 45 seconds until I'm faster than 2km/sec. After that I shut down and coast up to it. Once I get within 15 seconds of Ap, I throttle as necessary to keep Ap 5 seconds ahead until circularized. You can use radial in or out to control where the Ap sits as well as the throttle. There's a more realistic method where radial aiming is used instead of throttling, but we'll save that for another day. Glad to see you coming along! -Slashy

The UP Big Boy is always awesome, but what about the Dreyfuss Hudson streamliner? It'd probably be fairly easy to make with stock parts. Best, -Slashy

Yeah, just throwing it out there. If it were me I wouldn't bother putting jet engines on a Duna SSTO. Or sometimes- jet engines that are overweight and inefficient. I think the sandwich lifter is the way to go. Best, -Slashy

xendelaar, Option #3: Build an SSTO that can just get to Kerbin orbit. Refuel it there, then proceed to Duna. Best, -Slashy

xendelaar, That was just a way to get the thrust centers as close to the center of mass as possible while leaving room for the payload and keeping the stack short. It's not actually required, just convenient in some cases. Best, -Slashy

Der Anfang, rearranging these motion equations is simply a matter of straight algebra. ((t/2pi)^2*GM)^(1/3)=a Best, -Slashy

xendelaar, 5thHorseman is talking about this: Definitely an easy way to go, as the wings stabilize the stack instead of destabilizing it. Best, -Slashy

The HALO Halcyon class light cruiser and Starship Troopers USS Rodger Young. Both have the feel of current naval technology and doctrine in space. They have an air of plausibility about them... Best, -Slashy

Well, see that's the thing... I don't know that they are actually capable of building military grade electronic components. Mass- producing even something as simple as an FPGA requires a very sophisticated infrastructure. Making something that will survive the rigors of spaceflight is even more so. I don't know if DPRK has that capability. Without that, they'd be reduced to using off- the- shelf through- hole analog tech and potting the bejeezus out of it. You can make something that will survive that way, but it's not going to be light or capable of any more than bare- bones operation. We're talkin' Redstone level sophistication. But I don't know what their capabilities are. That's why I'm asking. Best, -Slashy

Foxster, Just for grins, I decided to go with an asymmetrical launcher because "Thud". According to my math, it still has 268 m/sec DV on orbit. Best, -Slashy

^ This. It takes very little beyond escape velocity to get an atmospheric periapsis if you do it this way. Best, -Slashy

Yeah, this is what I was talking about. It seems to me that a vacuum chamber would be pretty easy to do. The hard part is making electronic components that will withstand the rigors of spaceflight. Is anybody actually selling DPRK military- grade electronic components? Best, -Slashy

I very rarely use more than 2 stages to orbit. I'll have to review the numbers on it. *edit* My quick back- of-the- envelope says you have just barely enough DV to do the job. I concur with Harry Rhodan; that extra stage isn't doing you any favors. I estimate your LV-909 can handle a lot more of the workload. I design them to hit a minimum .7G and your design is getting about 2G. Your lowest stage is also a little overworked. My math says to expect 1.2G out of the gate. I design mine to hit 1.4G. 2 stages can do this efficiently. The T45 in the middle is essentially a ton and a half of dead weight. I also noticed that the fins may be a bit high on yours, which would cause it to be a little too unstable to track cleanly. Finally, your initial prograde kick looked like it was way too early and aggressive. Best, -Slashy

This can be answered by the uniform circular motion and vis-viva equations. v= sqrt(GM/r) where v=orbital velocity in m/sec G= universal gravitational constant 6.67x10^-11 M= parent body mass in grams r= orbital radius in meters (from parent center, *not* altitude) v= sqrt(GM(2/r-1/a)) same as above and a=semi-major axis; the mean radius of your elliptical orbit If you're in an 80x80 orbit then you have an orbital velocity of 2279 m/sec. If you wish to deorbit, then the cost in DV depends on where you wish to set your periapsis. I usually go for 45km. Setting that up would require a retroburn of 30.3 m/sec. If you wanted to set up an elliptical orbit with an 80 km periapsis with 100 m/sec DV, you could set your apoapsis to 214,000m. You could do a hohmann transfer to a 144,000m circular orbit. Best, -Slashy

Kryxal, Best I can say is that hasn't been my experience. When dealing with non- pilots and no SAS, I've found it helpful to design the booster so that it follows a gravity turn on it's own with minimal input. YMMV, -Slashy

Serious question: How hard is it *really* to build a thermal vacuum testing chamber? I wouldn't think it'd be all that difficult to do, even for an amateur. Is DPRK's problem really an inability to produce a proper R&D facility, or their inability to produce acceptable components? Best, -Slashy

Coyote27, Just a matter of balance. If the fins are too far back it's excessively- stable. Putting them there makes the rocket want to naturally follow a gravity turn. That's important because the only source of guidance on these rockets is the reaction wheel in the command pod. If you design it to naturally tend to go where you want it to go, you need a lot less command authority. This aids stability when you don't have access to SAS. Best, -Slashy

I don't overlook them because "math". I use whatever engine the math tells me I should use Best, -Slashy

Jack Bush, No problem at all. We've all got to start somewhere and you're coming along just fine. I usually work it so that I keep the apoapsis 5-10 seconds ahead and adjust it with thrust. That way the apoapsis doesn't rise too much while I'm dumping energy into the orbit. Gives me a nice circular orbit without too much effort. Best, -Slashy

pawelk, It looks like you're at level 4 on the tech tree. Is that correct? I can get you to orbit at level 2 with starter facilities, but I can't bring the goo pods. Level 4 is no problem. Here's an easy to fly orbital lifter at lvl. 2 http://wikisend.com/download/506720/early2stager.craft Here's the lvl.4 version with science: http://wikisend.com/download/326644/early2stagerlv4.craft For both of them you keep it vertical to 90 m/sec velocity, then pitch prograde to 80°. After that, just keep the acceleration under 2G and keep the nose prograde. Best, -Slashy

pawelk, The trick to it is to keep the fins and thrust balanced so that it naturally follows a gravity turn. This requires minimal control and is naturally stable. Fins too far back or too much area = it wants to face plant at low speed and not tip over enough at high speed. I'll see if I can knock you together a very simple and low tech 2- stager to orbit. Best, -Slashy

^ I agree with all of the above. It appears to be initiating the flip due to an overly- aggressive initial turn and excessive acceleration off the pad. I just downloaded it and will try to fly it... if it will work on a stock install. *edit* "Contains invalid or locked parts". Sorry. It's a beautiful looking launcher. Best, -Slashy