GoSlash27

CliftonM, The force applied to your vehicle is 1/2*m*v^2. Since the force is proportional to the mass you're ejecting but the square of the velocity, the velocity is clearly the most important part. Moreover, the mass of the bullets is effectively your "fuel" so you're not going to get a very good wet/ dry ratio using bullets. Best, -Slashy

Fubarbrickdust, My calculation of DV isn't agreeing with that figure. What are the two mass figures in your post? *edit* if your mass at the moment of launch is 3.165t, then your DV figure is accurate enough to bank on and it's not enough to get him home. And I see that you're no longer on- line, so here's the plan assuming the mass is correct: 1) Put Bob in orbit and make sure his solar panels are deployed. We don't want him on the Munar surface with dead batteries. 2) Next, you already have a ship that can rescue him in orbit. It's the same one that put him on the surface. Just put a probe on it, kick out the crew, and make sure Jeb doesn't sneak aboard when you're not watching. We're gonna use that to link up with Bob in Munar orbit to bring him home. I'll show you how. You've got a fully-functioning recovery setup on the ship, I hope? You can get by without the heat shield if you're careful, but you gotta have the chute. Best, -Slashy

Fubarbrickdust, It'll keep until you get home. If the equipment does have the DV to get him home, I'll walk you through it. If it doesn't... we'll work the problem from there. You've already established that he can reach orbit, so that'll make it a lot easier than rescuing him from the surface. Don't worry. We'll get him back safe. Best, -Slashy

He must be rescued! I need some vital stats on his ship. -What is his fuel supply (units of fuel and o2)? -What is the mass of his ascent module? -What kind of engine is he using? I want to verify the DV. Best, -Slashy

You simply cannot have a human society without a reliable water supply. That's a fact of life. Without that you're reduced to roving bands of hunter- gatherers. California has grown their population and thus agriculture and water usage, but they haven't increased their water supply to match it. They could have, but chose not to. As for the rest of your post, I'm not gonna argue about it 'cuz it's just assumptions on your part that don't apply to me. I'm just really glad I don't live there. Best, -Slashy

California has plenty of water, they're just not building dams and reservoirs to hold it because 1) They already spent the money allocated for them on public employee pension funds and 2) Every time they try, it gets shut down by environmental lawsuits. So instead of controlling the water (which has been the basis of civilization all the way back to ancient Sumeria) they have flooding and mudslides in the spring and drought/ wildfires in the summer. If they can't build dams and reservoirs, how are they supposed to build a giant canal all the way to Canada? Best, -Slashy

Alshain, A semi-disposable vertical lifter (disposable first stage and recoverable upper stage) will always beat a shuttle for cost- effectiveness and it's much easier to design and use. sardia, I use spaceplanes for crew and supplies to LKO, but never cargo (small or otherwise). They *can* be used to carry cargo and they're cheaper when they are, but I don't think they get used often enough to justify their existence and they limit the size and shape of the cargo. Best, -Slashy

Hechicicero100, You should blend the stayputnik into the rocket more cleanly and turn down the thrust on the SRBs to 50%. Best, -Slashy - - - Updated - - - Best, -Slashy

RokkitScientist, I don't use RSS, but the technique would be the same. Basically you use a resonant parking orbit to interface with the geosynchronous orbit so that they act like a set of gears. You use period instead of radius, but otherwise the concept is the same. If you have an orbit with 24hr period and wish to precisely space 3 sats on it, you would use an elliptical orbit with a period of 16 hours and an apogee equal to the altitude of the geosynchronous orbit. In sidereal space, the resonant orbit makes a full rotation in 16 hours, but the GSO only makes 2/3 of a rotation. When your sat gets to apogee the first time, it's at an arbitrary longitude "zero". Next time around, it's advanced 1/3. Then 2/3 and finally back to 0. For the math, we worry about semimajor axis (or average radius) and period. We have to flip back and forth between them. μ=GM where G= the universal gravitation constant; approx. 6.674x10^-11 M= Earth's mass in kilograms; approx. 5.972x10^24 to find an orbit's period by it's radius or SMA p= 2*pi*sqrt(r^3/μ) where pi= approx. 3.142 r= the orbit's radius in meters and conversely r= cuberoot( μ(p/(2pi)^2) It's important to remember that if you stretch an orbit to be elliptical, the apogee is just as much higher than the SMA as the perigee is below it such that r=(Pe+Ap)/2 So for the process, 1) Place a control module on KSC grounds pointed up so it can track sats as they pass overhead. 2) Place the vehicle into a temporary parking orbit with a convenient orbital period. I like to use 101,306m for the stock game because it passes overhead KSC precisely once every 36 minutes. You will have to pick a different parking orbit for RSS. 3) figure out the transit time from this parking orbit to the GSO altitude. This is 1/2 the period of the SMA of the transfer orbit. 4) Figure out how far the Earth will rotate in that time. 5) Since it has a convenient orbital period, it's easy to convert longitude to time. Figure out the latitude of the burn, then convert to time. 6) Burn at the required time to set GSO apogee. 7) Upon arrival at apogee 7a) if a single sat, burn to circularize at GSO 7b) if multiple sats on a single bus, burn to establish resonant orbit perigee and kick off/ circularize first sat. 8) at apogee, kick off and circularize second sat and so on 9) after all sats deployed, at apogee burn retrograde to deorbit bus. Now... if you're doing individual launches, you would orbit the first and then target it on the next launch to get an intercept. At apogee, you would raise the perigee to the resonant perigee and circularize on the next pass. Voila; perfectly- spaced sats! HTHs, -Slashy

Yeah, you really can do that. Best, -Slashy

I have a radical idea: Circularize around Laythe instead of Jool. It will carry you around to the target orbit's plane for free. Then eject from Laythe to match your Pe to the target orbit. as soon as you escape Laythe's SoI, fix your inclination while the velocity is low. This is the cheapest solution I can think of. Best, -Slashy

I realize that this is intended to be tongue-in-cheek, but a lot of people *actually* try to run their space programs in accordance with rules #1 and #2 and then wonder why their rockets are bloated laggy uncontrollable messes. So for those who are struggling, I would like to point out: "Moar boosters" and "moar struts" is just a running joke, not actual advice. Best, -Slashy

https://youtu.be/ZAQOf7Kwb2M?t=1652 This is not a good rocket design. Too short, too wide, too draggy, too powerful. Make it weaker, make it look like a real rocket, and fly it like a real rocket. Also, ^ what Harry Rhodan said. Good luck, -Slashy

As long as you're playing around with stage recovery, this one should be your best bet: Cheep 20 craft file This one does 20t for 20 grand. Just boost vertically until 60m/sec then hold D until SRB burnout. Best, -Slashy

Norcalplanner, I would imagine if you're using stage recovery it'd be in your best interest to make more of the total DV come from the booster stage and less from the insertion stage. Also, I've got that stack up to 38t payload now. Best, -Slashy

Cool! I'll have to give it a go and document how it turns out. Best, -Slashy

maltesh, What I mean is if I kick off and circularize the first sat directly from the initial transfer orbit, can I plot this from the transfer orbit and then go directly into the resonant parking orbit? Or will it not plot that way? I'd expect it would, but just want to be sure. Best, -Slashy

maltesh, Would this technique still work if you don't circularize the entire bus? I like to leave my bus in the resonant orbit and kick off/ circularize the sats independently. Best, -Slashy

maltesh, Yeah, I had just looked that over. Pretty freakin' brilliant! That would simplify things immensely. I'll have to try it out. Best, -Slashy

HECHICERO100, Pointy at the front, draggy at the back. And try to keep to a tall skinny design with the weight closer to the front. Better yet, read this: http://forum.kerbalspaceprogram.com/threads/117876-Why-Does-My-FLIPing-Rocket-Always-Flip-Over!-%28Easy-Picture-Explanation%29 Best, -Slashy

Actually, even using the math it's still difficult. The problem lies in the fact that you don't know precisely how much time it will take to get to orbit from the pad and once you do know that, it's highly variable from one launch to the next. What I do is first launch into a parking orbit with a fixed period (for example 11 orbits per day, which passes over KSC 10 times per day). I can then track it and mark the time that it passes over KSC (using a guidance head on KSC grounds) and compute down to the second when to begin the transfer. The math is a lot hairier than it is for the single launch resonant spacing setup. Best, -Slashy

Alshain, Yeah, I'd imagine that's why you're having trouble with it. When done properly, no adjustment is necessary. The parking orbit is computed to be perfectly resonant with the final orbit, so the correct spacing is assured. What I mean to say is that if you're setting up a constellation without any mods, then you need to plan out the process mathematically. In that situation, it's much easier to do a one- up launch than it is to do a bunch of individual launches. I can well- imagine that if you are using mods, then the advantage of doing a one- up launch would be reduced or even eliminated. Best, -Slashy

^ Truthiness. I use a mix of both. Spaceplanes for the stuff that spaceplanes excel at and vertical lifters for the rest. *edit* as long as we're showing our spaceplanes... Big heapin' helpings of fuel and o2 to orbit for cheap. Best, -Slashy

Alshain, That's cool. We just have different definitions of "easier". What I mean by "easier" is getting the sats into position. If you do a single launch with a resonant orbit, you set up a machine that neatly drops the sats where they're supposed to be like intermeshing gears, no adjustments necessary. If you launch them one at a time, then you wind up with a ragged constellation that requires you to adjust each sat to get it where it's supposed to be. But I suppose it's a different problem if you use mods to assist in the process. Best, -Slashy

DC, Figuring out the distances between satellites doesn't really help solve the problem of how you're going to get the satellites in position. What you really need to know is orbital period from orbital radius and vice- versa. For Kerbin, period (in seconds) is p= 2À√(r3/µ) where r= orbit radius from Kerbin's center in meters. Subtract Kerbin's radius (600km) to get altitude. and µ= Kerbin's mass x std gravitational constant; approx. 3.5316x10^12 in cubic meters per second squared. algebraically flipping this around, r=3√[µ(p/2À)2] To get sats into precise positions, you play around with orbital periods rather than distances. For example, if your final orbit had a period of 1 hr, you might use an elliptical parking orbit with the Ap at the desired altitude and an orbital period of 40 minutes. Or you might pick a higher parking orbit with a Pe at the desired orbit and an orbital period of 1hr 15 minutes. It's much easier to do if you launch all of the sats into a parking orbit in 1 bus assembly and kick off the individual sats 1 at a time. If that's not an option, then the process gets a great deal more complicated. You have to figure out launch windows based on time, track when the sats pass overhead KSC, then correct their orbits as necessary. Best, -Slashy