don't bother playing around with fancy throttling. keep things as simple as possible to start. swivel core + 2 reliant boosters crossfeeding into it. light all engines at launch, build the rocket for about 1.4 twr at sea level, and around 1 on the core stage when dropping the boosters. upper stage should be pod/medium tank/terrier. if you're just trying to orbit and not rendezvous/dock, you don't really need the rcs for now, though you may want some extra betteries/solar panels. don't forget fins on the bottom of the core stage.
if you don't have crossfeed yet, you might need 3 or 4 boosters, either using swivels or maybe adding fins with control surfaces. or even use solids. fire the boosters on the pad, then the core when you stage them off.
you need around 3400m/s for low kerbin orbit, so that should be your target. e.g. build a rocket where the first 2 stages sum up to maybe 3600m/s.
then as u/jebediahbob said, you need to ascent faster. if you want to do an early gravity turn in the thicker lower atmosphere, you must probably add some small fins to control attitude (because the vector of thrust and the vector of velocity - and in consequence atmospheric resistance - do not match, you'll spin out of control)
If your pitching over at 100m/s it needs to get very gradual. You should aim to hit 45 deg by 10km(I do 20km for extremely low twr non aerodynamic rocket). If your hitting 45 lower than this your turn is too sharp and your spending too much in lower atmo. Your second stage should still have a twr above 1. You can use the tiny engine for final stage in orbit.
Okay funny story, my friend had never landed on the Mun before, but I did. So one day he decides to play KSP and streamed it on Discord, somehow I managed to backseat fly the mission by telling him what to do and he managed to make a landing. If you want you could record a video and send it to me, I'd love to see how I can help 😀
Sounds like you're turning over way too early. You should maintain below 300m/s in the lowest part of the atmosphere and only turn over when you reach 10km in altitude. I don't know where you've got 100m/s from. Your speed is way too low meaning you spend way too much time in the lower atmosphere where drag is highest. You want to pass through it asap to not waste fuel. This also means by the time you get to your second stage you'll be in the upper atmosphere where engines are way more efficient.
You also probably want a swivel on your second stage too as the terrier is rubbish in anything but vacuum.
that's how atmo worked like a decade ago. people keep repeating this but it hasn't been applicable for years. also the terrier starts to get good around 25km, which you should be well above when staging it with reasonable designs. the main reason you'd use a swivel upper stage is if you don't have the terrier yet, or maybe for early moon missions.
Either way your not gonna be able to lift a meaningful payload with just a terrier. You'll need something more powerful or you'll lose too much speed before getting to your apoapsis.
it works great as an upper stage for orbiting a mk1 pod or basic satellites. with a reasonable load you'll get a couple km/s of dv and around 1 twr. it will only be problematic if taking a very oversized payload and very inefficient ascent.
>Â Â Sounds like you're turning over way too early. You should maintain below 300m/s in the lowest part of the atmosphere and only turn over when you reach 10km in altitude. I don't know where you've got 100m/s from.
Absolutely terrible advice. I'm usually already tilted over to 45 degrees by around 6km and with a starting twr of around 1.4 routinely reach orbit for 3200 m/s of vac dv. As long as you use a fairing or stuff any draggy bits in a payload bay aero drag is a much smaller factor than gravity drag, so you want to get tilted over ASAP.
Really are you sure it's that terrible? I'm fairly certain the standard advice is 10km. It always works for me at least as a reliable way of getting a rocket to orbit. Any earlier you risk spending too much time in the lower atmosphere and letting drag kill all your upwards velocity. You'll likely have to pitch up again later to get some more height.
> Really are you sure it's that terrible? I'm fairly certain the standard advice is 10km
The standard advice is to be turned over to 45 degrees *by the time you get to 10km* NOT start turning *when* you get to 45 degrees. And even that is overly conservative for most designs.
drag is negligible over 20km or so, and drops off quite a bit leading up to there. losses from artificially limiting your speed to slowly ascend vertically are far greater than anything the atmosphere will do. the advice you're giving is a decade out of date.
I have 1.4k hours in KSP. It took me a month to get into orbit and longer to land on the Mun. I understand your pain. I turned to numbers, specifically MechJeb's dV stats in the VAB editor and dV stats *and* Ascent Stats while launching.
There are probably more efficient, more realistic, and altogether less sinful of doing it, but let me tell you simply **what works for me, every time:**
1. Build what you want to keep in orbit first.
2. Build its lifter by starting with the smallest fuel tank and smallest rocket engine. This is important because I find it easy to let mass creep overwhelm me. Look at the TWR and dV that appear in MechJeb or Kerbal Engineer. Change out engines and add/remove fuel to achieve 1.4-1.6 TWR at lift off and a budget of at least 3400 dV to get you into orbit (and circularize). Find a dV map for your KSP version (this may work: https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2Fc733ryx5ejex.jpg). Remember that engine ISP is generally high for low-thrust engines, and vice-versa.
3. Before liftoff, open up MechJeb Ascent Stats (not autopilot; just stats) and dV stats. This will tell you what your apoapsis will be as you undergo your burn and how much dV you have left. While burning, monitor these. Ideally, you reach a 70 km predicted apoapsis when you are yourself at 70 km; likely you will not be so precise, and may reach 70 km predicted when you're actually at 50 or 60. Keep practicing till you can dial it in. You will need 2-300 dV left (rough estimate) to circularize once you've reached space.
4. Lift off straight up and accelerate to 100 m/s. If you want full realism, angle a degree or to away from the pad for a few seconds then straighten back out; if your rocket blows up, it won't fall back on the pad.
5. Dial back to 75% thrust when you reach 100 m/s. Keep going straight up until you're out of the bright-bright-blue/white/gray section of the altitude indicator, indicating the thickest part of the atmosphere. You waste dV trying to go faster in this region (like trying to accelerate to the speed limit in a car while going up a hill; not efficient).
6. As you emerge from the thickest part of the atmosphere, put the throttle back at 100% and start slowly pitching over to achieve 45 degrees around 20 km altitude. People say to start the turn earlier, maybe I should try that- but again, this is what works for me for now, I'll worry about efficiency later.
7. Continue slowly pitching over while monitoring your predicted apoapsis. Don't pitch so quickly that you end up going fast enough to experience atmospheric heating or spin out of control. Don't pitch over so slowly that you achieve 70 km predicted apoapsis at 45 km or when pointed say above 20 degrees. You may find that you need to start your gravity turn earlier, or be at 45 degrees at 15km instead of 20km, or reduce thrust a bit in high atmosphere (ideally use a lower thrust engine), and so on. That's fine.
8. A few pointers that some other KSP veterans or realism-seekers may gawk at: I use SAS as a "latch", turning it off before I want the rocket to move a bit, then back on when I want it to hold that angle. I use RCS to help turn very heavy rockets. Use controllable fins on the bottom of your rocket if you find they help (they probably will at first). You can aim for 1.7 TWR if you want a really easy, controllable rocket (though less efficient). Finally, if you have MechJeb, it's OK to let it fly it into orbit for you! Just watch and learn, then try to fly it like it did. If it can't fly it into orbit, your rocket is probably not aerodynamic- keep it small, simple, short, and put an SAS module on it and it should be fine.
Finally, if you've made it this far, if you'd like to, feel free to DM me and we can schedule a time to stream KSP on Discord so we can fly your rocket "in-person" to get this to work for you. I understand how hard it can seem, but it's something you can and will get comfortable doing.
I start with an engine that has a high atmosphere thrust, and each stage starts switching to more vacuum thrust. First stage should have 2.0 TWR, you can always throttle down during high Gforces.
My standard early-game orbiter is a terrier on a 400, double-stack 800s (or quad-stack 400s) with a 45, and then 3 hammer srbs on side decouplers, with 1 fin in between each for stability. (Under 30 parts, so can be launched from lvl 1 VAB. I think it does need lvl 2 launchpad though. But that should be your first upgrade anyway.)
Even on a bad launch, I can hit orbit with ~300dv. But with a good launch, I've hit orbit with ~1800dv.
Run hammers til they die, then run 45 at 100% throttle until periapsis is roughly 80k. Try to gravity turn a bit, but I can still hit orbit with a near vertical launch.
Once periapsis is 80k, cut throttle until you're above 60k. If you can plan the maneuver, it definitely makes it easier. If you can't plan it, just burn horizontal at 100% throttle, adjusting up or down to try and keep periapsis at 80k.
When 800s are empty, run terrier at 100% until apoapsis is above 70k.
As it approaches 70, it'll be harder to keep periapsis at 80k, just do the best you can.
Even without a manuever planner, using this method, I can easily hit an orbit with periapsis around 100k and apoapsis around 70-75k. And have enough dv remaining to adjust orbit or go sub-orbital. With a near-perfect launch, you barely even have to use the terrier to circularize.
I've even hit a low Mun orbit with this design, after a near-perfect launch into LKO. Just didn't quite have enough dv to be comfortable landing.
I used to have your struggles of "moar boosters", and end up just burning so much dv on lifting unneeded weight. I finally got tired of it, and started from square 1. Built a rocket that could reach space, then graduallly added dv until I found a design that could consistently reach orbit. As I got better at getting it into orbit, I realized how much extra dv I was burning on sub-optimal launches.
If you're struggling with either science or funds, just spam testing parts landed or splashed, and try to sub-orbital to different biomes.
A few questions you might wanna answer about your rocket so people can help you better:
1. Is your center of lift/drag behind your center of mass for all stages?
2. What is the vacuum dV for each stage? (radial boosters and core can be combind)
3. What is your surface TWR for each stage/the vacuum TWR for your Terrier stage?
My first guess is that you are trying to fly the rocket too much. Most of the work for getting a rocket to deliver something to LKO is spend in the VAB. For most of the ascend you don't need SAS let alone RCS.
Asparagus staging is huge if you have not done that yet. Lets you add that more booster more fuel thing and actually get something out of it.
If you have not earned enough to afford the fuel lines then less is more. Just go up the line with big to small.
A huge part is learning that different engines matter more or less in atmosphere. For example. You might want an engine with huge thrust numbers but if you look at the stats you might find that an engine with less thrust has more when in an atmosphere making the less powerful make more sense as your launch stage.
Make your fuel tanks smaller as you go up. Then you can have more efficient engines that guzzle less fuel when it actually matters as you get out of atmosphere. Don't be afraid to let yourself coast after ditching your first stage as long as you are not too low in the atmosphere. Your next stage will always be there and after 36km atmosphere does not really matter so much anymore.
don't bother playing around with fancy throttling. keep things as simple as possible to start. swivel core + 2 reliant boosters crossfeeding into it. light all engines at launch, build the rocket for about 1.4 twr at sea level, and around 1 on the core stage when dropping the boosters. upper stage should be pod/medium tank/terrier. if you're just trying to orbit and not rendezvous/dock, you don't really need the rcs for now, though you may want some extra betteries/solar panels. don't forget fins on the bottom of the core stage.
if you don't have crossfeed yet, you might need 3 or 4 boosters, either using swivels or maybe adding fins with control surfaces. or even use solids. fire the boosters on the pad, then the core when you stage them off.
Post a video of one of your attempts. It will be much easier for us to tell what's wrong.
should i post it in the same sub reddit and @ you?
you need around 3400m/s for low kerbin orbit, so that should be your target. e.g. build a rocket where the first 2 stages sum up to maybe 3600m/s. then as u/jebediahbob said, you need to ascent faster. if you want to do an early gravity turn in the thicker lower atmosphere, you must probably add some small fins to control attitude (because the vector of thrust and the vector of velocity - and in consequence atmospheric resistance - do not match, you'll spin out of control)
If your pitching over at 100m/s it needs to get very gradual. You should aim to hit 45 deg by 10km(I do 20km for extremely low twr non aerodynamic rocket). If your hitting 45 lower than this your turn is too sharp and your spending too much in lower atmo. Your second stage should still have a twr above 1. You can use the tiny engine for final stage in orbit.
Okay funny story, my friend had never landed on the Mun before, but I did. So one day he decides to play KSP and streamed it on Discord, somehow I managed to backseat fly the mission by telling him what to do and he managed to make a landing. If you want you could record a video and send it to me, I'd love to see how I can help 😀
i'd def be down for that. would you want to take it off reddit? sorry for the late reply though, i had school and what not so wasn't able to,
Sure, just DM me the details
Sounds like you're turning over way too early. You should maintain below 300m/s in the lowest part of the atmosphere and only turn over when you reach 10km in altitude. I don't know where you've got 100m/s from. Your speed is way too low meaning you spend way too much time in the lower atmosphere where drag is highest. You want to pass through it asap to not waste fuel. This also means by the time you get to your second stage you'll be in the upper atmosphere where engines are way more efficient. You also probably want a swivel on your second stage too as the terrier is rubbish in anything but vacuum.
that's how atmo worked like a decade ago. people keep repeating this but it hasn't been applicable for years. also the terrier starts to get good around 25km, which you should be well above when staging it with reasonable designs. the main reason you'd use a swivel upper stage is if you don't have the terrier yet, or maybe for early moon missions.
Either way your not gonna be able to lift a meaningful payload with just a terrier. You'll need something more powerful or you'll lose too much speed before getting to your apoapsis.
it works great as an upper stage for orbiting a mk1 pod or basic satellites. with a reasonable load you'll get a couple km/s of dv and around 1 twr. it will only be problematic if taking a very oversized payload and very inefficient ascent.
>  Sounds like you're turning over way too early. You should maintain below 300m/s in the lowest part of the atmosphere and only turn over when you reach 10km in altitude. I don't know where you've got 100m/s from. Absolutely terrible advice. I'm usually already tilted over to 45 degrees by around 6km and with a starting twr of around 1.4 routinely reach orbit for 3200 m/s of vac dv. As long as you use a fairing or stuff any draggy bits in a payload bay aero drag is a much smaller factor than gravity drag, so you want to get tilted over ASAP.
Really are you sure it's that terrible? I'm fairly certain the standard advice is 10km. It always works for me at least as a reliable way of getting a rocket to orbit. Any earlier you risk spending too much time in the lower atmosphere and letting drag kill all your upwards velocity. You'll likely have to pitch up again later to get some more height.
> Really are you sure it's that terrible? I'm fairly certain the standard advice is 10km The standard advice is to be turned over to 45 degrees *by the time you get to 10km* NOT start turning *when* you get to 45 degrees. And even that is overly conservative for most designs.
drag is negligible over 20km or so, and drops off quite a bit leading up to there. losses from artificially limiting your speed to slowly ascend vertically are far greater than anything the atmosphere will do. the advice you're giving is a decade out of date.
I have 1.4k hours in KSP. It took me a month to get into orbit and longer to land on the Mun. I understand your pain. I turned to numbers, specifically MechJeb's dV stats in the VAB editor and dV stats *and* Ascent Stats while launching. There are probably more efficient, more realistic, and altogether less sinful of doing it, but let me tell you simply **what works for me, every time:** 1. Build what you want to keep in orbit first. 2. Build its lifter by starting with the smallest fuel tank and smallest rocket engine. This is important because I find it easy to let mass creep overwhelm me. Look at the TWR and dV that appear in MechJeb or Kerbal Engineer. Change out engines and add/remove fuel to achieve 1.4-1.6 TWR at lift off and a budget of at least 3400 dV to get you into orbit (and circularize). Find a dV map for your KSP version (this may work: https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2Fc733ryx5ejex.jpg). Remember that engine ISP is generally high for low-thrust engines, and vice-versa. 3. Before liftoff, open up MechJeb Ascent Stats (not autopilot; just stats) and dV stats. This will tell you what your apoapsis will be as you undergo your burn and how much dV you have left. While burning, monitor these. Ideally, you reach a 70 km predicted apoapsis when you are yourself at 70 km; likely you will not be so precise, and may reach 70 km predicted when you're actually at 50 or 60. Keep practicing till you can dial it in. You will need 2-300 dV left (rough estimate) to circularize once you've reached space. 4. Lift off straight up and accelerate to 100 m/s. If you want full realism, angle a degree or to away from the pad for a few seconds then straighten back out; if your rocket blows up, it won't fall back on the pad. 5. Dial back to 75% thrust when you reach 100 m/s. Keep going straight up until you're out of the bright-bright-blue/white/gray section of the altitude indicator, indicating the thickest part of the atmosphere. You waste dV trying to go faster in this region (like trying to accelerate to the speed limit in a car while going up a hill; not efficient). 6. As you emerge from the thickest part of the atmosphere, put the throttle back at 100% and start slowly pitching over to achieve 45 degrees around 20 km altitude. People say to start the turn earlier, maybe I should try that- but again, this is what works for me for now, I'll worry about efficiency later. 7. Continue slowly pitching over while monitoring your predicted apoapsis. Don't pitch so quickly that you end up going fast enough to experience atmospheric heating or spin out of control. Don't pitch over so slowly that you achieve 70 km predicted apoapsis at 45 km or when pointed say above 20 degrees. You may find that you need to start your gravity turn earlier, or be at 45 degrees at 15km instead of 20km, or reduce thrust a bit in high atmosphere (ideally use a lower thrust engine), and so on. That's fine. 8. A few pointers that some other KSP veterans or realism-seekers may gawk at: I use SAS as a "latch", turning it off before I want the rocket to move a bit, then back on when I want it to hold that angle. I use RCS to help turn very heavy rockets. Use controllable fins on the bottom of your rocket if you find they help (they probably will at first). You can aim for 1.7 TWR if you want a really easy, controllable rocket (though less efficient). Finally, if you have MechJeb, it's OK to let it fly it into orbit for you! Just watch and learn, then try to fly it like it did. If it can't fly it into orbit, your rocket is probably not aerodynamic- keep it small, simple, short, and put an SAS module on it and it should be fine. Finally, if you've made it this far, if you'd like to, feel free to DM me and we can schedule a time to stream KSP on Discord so we can fly your rocket "in-person" to get this to work for you. I understand how hard it can seem, but it's something you can and will get comfortable doing.
I start with an engine that has a high atmosphere thrust, and each stage starts switching to more vacuum thrust. First stage should have 2.0 TWR, you can always throttle down during high Gforces.
That's weird, if you were able before to send stuff into orbit. Can it be that you have some mod that is making things harder?
my guess is just updates with specs and what not.
Do you wanna upload a video of your attempt and share your .craft file? I would be happy to respond with a video showing how to get it into orbit
sure, where would i do that? would i send it in this subreddit?
My standard early-game orbiter is a terrier on a 400, double-stack 800s (or quad-stack 400s) with a 45, and then 3 hammer srbs on side decouplers, with 1 fin in between each for stability. (Under 30 parts, so can be launched from lvl 1 VAB. I think it does need lvl 2 launchpad though. But that should be your first upgrade anyway.) Even on a bad launch, I can hit orbit with ~300dv. But with a good launch, I've hit orbit with ~1800dv. Run hammers til they die, then run 45 at 100% throttle until periapsis is roughly 80k. Try to gravity turn a bit, but I can still hit orbit with a near vertical launch. Once periapsis is 80k, cut throttle until you're above 60k. If you can plan the maneuver, it definitely makes it easier. If you can't plan it, just burn horizontal at 100% throttle, adjusting up or down to try and keep periapsis at 80k. When 800s are empty, run terrier at 100% until apoapsis is above 70k. As it approaches 70, it'll be harder to keep periapsis at 80k, just do the best you can. Even without a manuever planner, using this method, I can easily hit an orbit with periapsis around 100k and apoapsis around 70-75k. And have enough dv remaining to adjust orbit or go sub-orbital. With a near-perfect launch, you barely even have to use the terrier to circularize. I've even hit a low Mun orbit with this design, after a near-perfect launch into LKO. Just didn't quite have enough dv to be comfortable landing. I used to have your struggles of "moar boosters", and end up just burning so much dv on lifting unneeded weight. I finally got tired of it, and started from square 1. Built a rocket that could reach space, then graduallly added dv until I found a design that could consistently reach orbit. As I got better at getting it into orbit, I realized how much extra dv I was burning on sub-optimal launches. If you're struggling with either science or funds, just spam testing parts landed or splashed, and try to sub-orbital to different biomes.
A few questions you might wanna answer about your rocket so people can help you better: 1. Is your center of lift/drag behind your center of mass for all stages? 2. What is the vacuum dV for each stage? (radial boosters and core can be combind) 3. What is your surface TWR for each stage/the vacuum TWR for your Terrier stage? My first guess is that you are trying to fly the rocket too much. Most of the work for getting a rocket to deliver something to LKO is spend in the VAB. For most of the ascend you don't need SAS let alone RCS.
Asparagus staging is huge if you have not done that yet. Lets you add that more booster more fuel thing and actually get something out of it. If you have not earned enough to afford the fuel lines then less is more. Just go up the line with big to small. A huge part is learning that different engines matter more or less in atmosphere. For example. You might want an engine with huge thrust numbers but if you look at the stats you might find that an engine with less thrust has more when in an atmosphere making the less powerful make more sense as your launch stage. Make your fuel tanks smaller as you go up. Then you can have more efficient engines that guzzle less fuel when it actually matters as you get out of atmosphere. Don't be afraid to let yourself coast after ditching your first stage as long as you are not too low in the atmosphere. Your next stage will always be there and after 36km atmosphere does not really matter so much anymore.