Basic Mun Flyby rocket design?

[ADKGuy]

Hi everyone,

I’m super new to KSP. I’ve managed to get into Kerbin orbit using the excellent tutorial by quill18 on YT. 
 

When he moves on to Get to the Mun, he doesn’t get into the rocket design well enough for me to replicate it. It doesn’t help that the designs of the parts have changed between his version of the software and mine (newest). 
 

Any rocket I build starts to roll when my liftoff speed gets to around 100m/s when I need start to make my turn to 90° so that I end up being at 45° on the NavBall when I reach 15000m per his tutorial. This is the only way I know to get to orbit so far. 
 

Can anyone tell from looking at the rocket what parts he’s built the rocket from so I can stick as close to the tutorial as possible?

Here’s the tutorial:

TIA for any assistance  

 

[Gargamel]

Welcome to the forums, you'll find a lot of good info here, sometimes a lot easier to read how to do something rather than waiting through an hour long video.  Check out our tutorials subforum for a lot of these.

18 minutes ago, ADKGuy said:

Can anyone tell from looking at the rocket what parts he’s built the rocket from so I can stick as close to the tutorial as possible?

I see the publish date on the video was 2017.  The parts have gone through some cosmetic work since then, so your rocket will probably not look like the video at all.   But also, one of the joys of KSP is doing things your own way.  Somebody here will be able to tell you exactly which parts he used, but why not try your own?  Build your rocket, have it fail, figure out where the failure point is, and try again.  To me, learning by trial and error is far more rewarding than following a set script. 

[StrandedonEarth]

You didn't post a pic (you have to host it at imgur.com or another hosting site, then paste the link to it), but a roll sounds familiar. I'm guessing you have some radially-attached boosters, which may be a bit wobbly. That can easily make it roll. Use autostrut set to grandparent part (right-click the booster to get the menu; you may have to enable "Advanced Tweakables" in the settings), or use the struts found under the Structural tab to make them more stable. That will probably stop the roll from happening.

[jimmymcgoochie]

Just looking at the rocket in that video, to me it looks like (from top to bottom):

Parachute- Mk1 crew pod with Z-100 battery, mystery goo can, barometer and thermometer on it- heat shield (1.25m)- decoupler (1.25m)-materials bay- FL-T400 fuel tank- terrier engine- decoupler (1.25m)- 3x FL-T400 tanks- swivel engine on the bottom, with 2x radial decouplers on the first stage and Hammer solid boosters with basic nosecones on top.

It's one way of getting to the Mun, sure, but if you have small parts (oscar-B tanks and spark engine) you'd be better off using those and a small probe core e.g. OKTO, HECS, or OKTO2 with a small reaction wheel, as smaller payloads require considerably less effort to get them into orbit; add an experiment storage unit to collect the science from the experiments, an antenna if you're using CommNet to stay in touch with Kerbin and a couple of solar panels to keep the power on and you should be able to orbit the Mun and return without too much difficulty. Crew pods are heavy, probes are generally much lighter.

To fly out to the Mun, try to launch into a completely flat (0 inclination) orbit around Kerbin, then wait until the Mun is directly ahead of you when pointing prograde and fire your engine until your apoapsis meets the Mun's orbit- just try not to get too close to the Mun or you might end up crashing instead of orbiting!

[Streetwind]

@StrandedonEarth - He doesn't actually have a problem with launching or woblly rockets. He just described that he begins his gravity turn once his rocket reaches 100 m/s, to give us an idea of his approach to spaceflight up until now. The correct term is of course "pitch over", not "roll", but then again he's a complete newcomer so we can't expect him to get the lingo right from the get-go.

@ADKGuy - Don't sweat the "it's better to do this" stuff right now. There are many ways that work, and it's okay to learn one of them first, even if it isn't the most optimal one. However, I would echo what @Gargamel said - don't rely overmuch on rockets that other people build. You may not realize it, but building the thing you fly later is just as important (or maybe even more important!) than actually flying it. Steering a rocket into orbit is good and all, but did you understand why this rocket made it into orbit while another did not?

It's quite daunting to get into the physics part of a physics simulator - to look at the alien numbers and units that are listed in the stats of the parts, and to try and figure them out. But the further you get into the game, the less you will be able to achieve without learning this part.

So how about this? You already have rockets that make it into orbit, right? Well then. Try to put "more stuff" into orbit. Not just a pod, but something with an engine and a fuel tank. One that still has fuel in it when you reach orbit. Ideally, one that's completely full of fuel. Can you figure out what you need to do - to build - in order to have a lot of fuel left in orbit?

Then, see if you can reach the Mun with that. You might be surprised. There is a saying in spaceflight that goes "once you've made it into orbit, you're halfway to anywhere", and you'll find it very true.

Edited June 7, 2020 by Streetwind

[ADKGuy]

10 hours ago, Gargamel said:

Welcome to the forums, you'll find a lot of good info here, sometimes a lot easier to read how to do something rather than waiting through an hour long video.  Check out our tutorials subforum for a lot of these.

I see the publish date on the video was 2017.  The parts have gone through some cosmetic work since then, so your rocket will probably not look like the video at all.   But also, one of the joys of KSP is doing things your own way.  Somebody here will be able to tell you exactly which parts he used, but why not try your own?  Build your rocket, have it fail, figure out where the failure point is, and try again.  To me, learning by trial and error is far more rewarding than following a set script. 

I’ve tried a few designs of my own and they all have the same issue. Anything that has an attached SRB will start to roll with SAS on at a speed of about 100 m/s before I start to pitch. 

[ADKGuy]

 

 

10 hours ago, StrandedonEarth said:

You didn't post a pic (you have to host it at imgur.com or another hosting site, then paste the link to it), but a roll sounds familiar. I'm guessing you have some radially-attached boosters, which may be a bit wobbly. That can easily make it roll. Use autostrut set to grandparent part (right-click the booster to get the menu; you may have to enable "Advanced Tweakables" in the settings), or use the struts found under the Structural tab to make them more stable. That will probably stop the roll from happening.

I’m trying to copy the rocket in the video. I do have two radially attached SRBs. I’ve tried moving the SRB up and down the end of the rocket as well as where the decouplers are but the result is the same a roll when I hit 100 m/s with SAS on before I start to pitch. 

Edited June 7, 2020 by ADKGuy

[ADKGuy]

1 hour ago, jimmymcgoochie said:

Just looking at the rocket in that video, to me it looks like (from top to bottom):

Parachute- Mk1 crew pod with Z-100 battery, mystery goo can, barometer and thermometer on it- heat shield (1.25m)- decoupler (1.25m)-materials bay- FL-T400 fuel tank- terrier engine- decoupler (1.25m)- 3x FL-T400 tanks- swivel engine on the bottom, with 2x radial decouplers on the first stage and Hammer solid boosters with basic nosecones on top.

It's one way of getting to the Mun, sure, but if you have small parts (oscar-B tanks and spark engine) you'd be better off using those and a small probe core e.g. OKTO, HECS, or OKTO2 with a small reaction wheel, as smaller payloads require considerably less effort to get them into orbit; add an experiment storage unit to collect the science from the experiments, an antenna if you're using CommNet to stay in touch with Kerbin and a couple of solar panels to keep the power on and you should be able to orbit the Mun and return without too much difficulty. Crew pods are heavy, probes are generally much lighter.

To fly out to the Mun, try to launch into a completely flat (0 inclination) orbit around Kerbin, then wait until the Mun is directly ahead of you when pointing prograde and fire your engine until your apoapsis meets the Mun's orbit- just try not to get too close to the Mun or you might end up crashing instead of orbiting!

At this point I’m trying to familiarize myself with the basic controls and mechanics of the game while at the same time having some fun.  I’m trying to understand what to push when, then I figured I‘d go back and learn the minutiae of all the various  settings etc. 

I wanted to start with something that works to understand the physics of what is going before I start messing with the variables and introducing multiple problems and get frustrated.

I’m playing sandbox so I have all the parts available and don’t have to worry about budgets and reputation and unlocking this and that.

I tried the in game tutorials but the Mun one quickly went over my head. 

Of course it doesn’t help that physics was my worse subject in college 20 years ago and math wasn’t far behind! (Side note: one of my professors went on to be head of the Nuclear Regulatory Commission during the semester and then another is friends with Buzz Aldrin). And I don’t use advanced math at all in daily life but I always loved space travel and the recent NASA/SpaceX launch had me on the look out for a space simulator and here we are. 
 

 

Edited June 7, 2020 by ADKGuy

[ADKGuy]

1 hour ago, Streetwind said:

@StrandedonEarth - He doesn't actually have a problem with launching or woblly rockets. He just described that he begins his gravity turn once his rocket reaches 100 m/s, to give us an idea of his approach to spaceflight up until now. The correct term is of course "pitch over", not "roll", but then again he's a complete newcomer so we can't expect him to get the lingo right from the get-go.

@ADKGuy - Don't sweat the "it's better to do this" stuff right now. There are many ways that work, and it's okay to learn one of them first, even if it isn't the most optimal one. However, I would echo what @Gargamel said - don't rely overmuch on rockets that other people build. You may not realize it, but building the thing you fly later is just as important (or maybe even more important!) than actually flying it. Steering a rocket into orbit is good and all, but did you understand why this rocket made it into orbit while another did not?

It's quite daunting to get into the physics part of a physics simulator - to look at the alien numbers and units that are listed in the stats of the parts, and to try and figure them out. But the further you get into the game, the less you will be able to achieve without learning this part.

So how about this? You already have rockets that make it into orbit, right? Well then. Try to put "more stuff" into orbit. Not just a pod, but something with an engine and a fuel tank. One that still has fuel in it when you reach orbit. Ideally, one that's completely full of fuel. Can you figure out what you need to do - to build - in order to have a lot of fuel left in orbit?

Then, see if you can reach the Mun with that. You might be surprised. There is a saying in spaceflight that goes "once you've made it into orbit, you're halfway to anywhere", and you'll find it very true.

Sorry to individually quote everyone!  I can’t figure out how to combine everyone’s answers in one post on my phone!  But I appreciate each and everyone of them. 
 

I actually think it may be a wobbly rocket. I might not have been clear in my description. The roll (and it’s a roll) starts at around 100 m/s with SAS on BEFORE I start my pitch. Just so happens the roll starts when I need to pitch and then I try to correct the roll and pitch and it quickly gets out of control.  When my SRBs run out and are jettisoned the craft stabilizes. But I then have a hard time getting to 45° by 15000 feet as mentioned in quill18’s tutorial. I end up burning a lot fuel trying to circularize my orbit because I didn’t enter orbit at the right angle. Then I don’t have enough fuel to burn to the Mun and return. If I try adding more fuel the extra weight slows my ascent and I still run out of fuel. 
 

 

[jimmymcgoochie]

@ADKGuy if you are genuinely having a roll problem (rolling on the long axis through the rocket that's corrected by Q/E keys) then you might need to add either A- a reaction wheel to the first stage to give it extra torque control, or B- some controllable fins to the first stage, such as AV-R8 winglets or delta-deluxe winglets, which can add aerodynamic control and stability to your rocket at low altitudes. You may also want to try rotating the crew pod by 90 degrees to face either away from or towards the VAB doors in the editor and thus point west/east on the launchpad; you might find pitching is more intuitive than yawing during your ascent.

Enable advanced tweakables in the main menu settings and use autostruts between the SRBs and their grandparent part, and between the nose cones and the root part, to keep them still and stabilise the rocket. You could also try turning the boosters' thrust limiter down to 50% which will decrease your raw acceleration- a thrust to weight ratio (TWR) of 1.5 to 1.8 is optimal, any lower and your rocket will waste fuel fighting against gravity, any higher and you'll lose speed to atmospheric drag especially if you go supersonic (~330m/s) at low altitudes.

On a point tenuously related to the original but directly related to boosters- stick small fuel tanks e.g. FL-T100 or T200 on top of your solid boosters and enable crossfeed on the radial decouplers; the extra fuel will feed the main engine before the tanks in the central stack and are then dropped with the boosters to save weight. It's a nifty way to get a bit more range out of your first stage and as they're on top of the boosters there's no penalty in terms of drag and very little in terms of mass. Bigger boosters can handle bigger fuel tanks, but just remember to use the move tool to shift the boosters down on their decouplers or else the extra weight of the fuel tanks can cause them to collide with your central rocket and potentially damage it or use sepratrons to push them away.

Here's a lander probe I just made; it's small, light and cheap but it can land on the Mun and return to Kerbin with fuel to spare. The first time I got a bit distracted finding the Armstrong Memorial and only made it back to Mun orbit with 1m/s left, so the second time I just landed right beside it then flew back to Kerbin.

Spoiler

First stage is made of 1x FL-T800 and 1x FL-T400 fuel tanks with a Swivel engine, plus 3x Hammer boosters turned down to 40% thrust (note the TWR on the pad is 1.41, it increases considerably as fuel mass decreases and engine ISP increases in thinner air), FL-T200 fuel tanks and nosecones. The decouplers are set to crossfeed enabled and the payload shroud is on the top of the first stage to save hauling it around in space for some extra range, 3x AV-R8 winglets for aero control and stability.

Second stage is just a FL-T400 tank and a Terrier engine plus an FL-A5 adapter to mount the lander on top.

The lander- OKTO2 probe core with 4x small solar panels, a small reaction wheel and a small heat shield on top and a Z-200 battery, 2x oscar-B fuel tanks and a spark engine on the bottom with 3x small landing legs on the tanks. There's also a 16-S antenna on top of the probe core, you can see it sticking out of the reaction wheel.

Armstrong Memorial- 0.745N, 22.725E. I landed on the second stage because there was still plenty of fuel left in it.

Re-entering directly from the Munar return orbit got a bit hot, the landing legs and solar panels didn't survive but everything else was fine.

And by complete coincidence entirely intentionally, I landed a mere 60km from the KSC.

This design could easily carry a science payload (experiment return unit with some experiments on it, but not a materials bay) to do a return trip; I just made a proof of concept version quickly.

 

[Streetwind]

 

2 hours ago, ADKGuy said:

The roll (and it’s a roll) starts at around 100 m/s with SAS on BEFORE I start my pitch. Just so happens the roll starts when I need to pitch and then I try to correct the roll and pitch and it quickly gets out of control.  When my SRBs run out and are jettisoned the craft stabilizes. (...) If I try adding more fuel the extra weight slows my ascent and I still run out of fuel. 

Hmmm. I see. Alright then, here's some very basic rocketry tips:

1.) Train your pilots. If you are playing with the Kerbal level-up experience system enabled (meaning, Kerbals are not five-star by default), then you want to send a few pilots into Kerbin orbit and back before you head anywhere else. Orbit around Kerbin is enough to get them to level 1, at which point they learn "SAS Hold Prograde". That means you can tell your Kerbal pilot to help you fly by trying to always keep the nose pointed in the direction of travel. You will find this invaluable while launching. There are also probe cores that have this ability, but unless you are playing sandbox mode, you have to put in some research effort to unlock them.

2.) "The golden rule of rocketry": heavy stuff at the front, draggy stuff at the back. Think of an arrow. The compact, pointy metal head is right at the tip. The light feathers that catch a lot of air are at the back. In technical terms, the center of mass is ahead of the center of pressure. This causes passive stability. A well-built, passively stable rocket can fly to orbit without turning on SAS and without touching the steering keys - only via managing the throttle. Though admittedly, in practical application not many player-built ships will be quite that stable, because payloads tend to be light and fuel tends to be heavy, which makes it hard to achieve this perfect distribution. Rather than taking this rule too far, take its opposite, and keep it in your mind as what not to do. Do not put wings or fins on the nose of your rocket, for example. And when you find yourself with a rocket that will not fly straight no matter what, then think of this rule when trying to find the reason.

3.) Single-size designs. A major source of instability is flexing joints, and few joints flex more than stepping down to a smaller part size in the middle of a stack and then stepping up again. This also causes drag, by the way, which (as we just learned) is bad if it happens towards the front of the rocket. As you progress in the game, you will gain parts (service bays, fairings, and engine plates) that allow you to shield smaller parts in the envelope of a larger one.

4.) Single-stack designs. Another thing that wants to flex like Dwayne Johnson hopped up on caffeine is a small radial decoupler carrying a large side booster producing massive thrust. You can use struts to try and fortify such boosters, or you can turn on advanced tweakables and simply magick away joint flexing via rigid attachment and autostrutting (if you do not feel cheaty by doing so), but you can also simply not have the problem in the first place by building your rocket without large radially attached boosters. The main limitation you have here is the thrust output of the launch stage engine. However, it is still easily possible to reach orbit on a single-stack, 1.25m size rocket. It is also possible to perform a Mun flyby and return to Kerbin on a single-stack, 1.25m rocket. Though to pull that off, you may need to get some practice in the next item on this list.

5.) Downsizing. Contrary to what you may think, bigger isn't always better. You will learn about this as you get deeper into the game (the keyword is "Delta-V"), but for now, what you need to understand is: how far a rocket can go does not directly scale with its size. The only thing that counts is the mass of the fuel you carry compared to the mass of "not-fuel" you carry. And no matter if your rocket is 10 meters in diameter or just 1 meter - if this ratio is the same, then both rockets will fly the same distance. So the takeaway should be: you must minimize everything that is "not-fuel". Take the fewest number of parts that are not fuel tanks as is possible. And if you have multiple parts that can fulfill a certain job you need done, pick the one that weighs the least - unless this causes other problems, such as having the wrong size. Besides helping with going further, this also helps with rocket building in general - if your rocket is light enough, you do not need extra boosters to make it move! And without extra boosters, you don't get flexing decoupler joints, which means your rocket won't go out of control on ascent...

To illustrate my point, let me show you the rocket I used for my initial Mun flyby the last time I played Career (well, Science mode, actually):

Spoiler

From the top down, that is: a MK-16 parachute, a MK1 command pod, a 1.25m service bay, a TD-12 decoupler, two SC-9001 "Sciene Jr." bays, a FL-T200 tank, a FL-T400 tank, a LV-909 "Terrier" engine, another decoupler, another four FL-T400 tanks, and finally a LV-T30 "Reliant" engine. Inside the service bay, there are two mystery goo containers, two thermometers, two barometers, and two Z-100 batteries.

Super simple. No radial boosters. No size mismatches. No struts. No advanced tweakables shenanigans. The whole thing weighs just 15.4 tons and contains just 23 parts, 8 of which are science instruments. It can be built and launched in career mode without needing any building upgrades whatsoever, and no tech tree node more expensive than 45 science. It actually has a healthy surplus of fuel for the Mun flyby mission - you could technically slim it down a little more still, but then again, you can never go wrong with some safety margin.

It is not 100% passively stable, but perhaps 99%. Adding four basic fins to the bottom will make it perfectly passively stable - a bit too stable for my tastes even, so stable that it becomes hard to make it turn in the lower atmosphere. Which is why I prefer it without fins.

Edited June 7, 2020 by Streetwind

[ADKGuy]

4 hours ago, jimmymcgoochie said:

@ADKGuy if you are genuinely having a roll problem (rolling on the long axis through the rocket that's corrected by Q/E keys) then you might need to add either A- a reaction wheel to the first stage to give it extra torque control, or B- some controllable fins to the first stage, such as AV-R8 winglets or delta-deluxe winglets, which can add aerodynamic control and stability to your rocket at low altitudes. You may also want to try rotating the crew pod by 90 degrees to face either away from or towards the VAB doors in the editor and thus point west/east on the launchpad; you might find pitching is more intuitive than yawing during your ascent.

Enable advanced tweakables in the main menu settings and use autostruts between the SRBs and their grandparent part, and between the nose cones and the root part, to keep them still and stabilise the rocket. You could also try turning the boosters' thrust limiter down to 50% which will decrease your raw acceleration- a thrust to weight ratio (TWR) of 1.5 to 1.8 is optimal, any lower and your rocket will waste fuel fighting against gravity, any higher and you'll lose speed to atmospheric drag especially if you go supersonic (~330m/s) at low altitudes.

On a point tenuously related to the original but directly related to boosters- stick small fuel tanks e.g. FL-T100 or T200 on top of your solid boosters and enable crossfeed on the radial decouplers; the extra fuel will feed the main engine before the tanks in the central stack and are then dropped with the boosters to save weight. It's a nifty way to get a bit more range out of your first stage and as they're on top of the boosters there's no penalty in terms of drag and very little in terms of mass. Bigger boosters can handle bigger fuel tanks, but just remember to use the move tool to shift the boosters down on their decouplers or else the extra weight of the fuel tanks can cause them to collide with your central rocket and potentially damage it or use sepratrons to push them away.

Here's a lander probe I just made; it's small, light and cheap but it can land on the Mun and return to Kerbin with fuel to spare. The first time I got a bit distracted finding the Armstrong Memorial and only made it back to Mun orbit with 1m/s left, so the second time I just landed right beside it then flew back to Kerbin.

  Reveal hidden contents

First stage is made of 1x FL-T800 and 1x FL-T400 fuel tanks with a Swivel engine, plus 3x Hammer boosters turned down to 40% thrust (note the TWR on the pad is 1.41, it increases considerably as fuel mass decreases and engine ISP increases in thinner air), FL-T200 fuel tanks and nosecones. The decouplers are set to crossfeed enabled and the payload shroud is on the top of the first stage to save hauling it around in space for some extra range, 3x AV-R8 winglets for aero control and stability.

Second stage is just a FL-T400 tank and a Terrier engine plus an FL-A5 adapter to mount the lander on top.

The lander- OKTO2 probe core with 4x small solar panels, a small reaction wheel and a small heat shield on top and a Z-200 battery, 2x oscar-B fuel tanks and a spark engine on the bottom with 3x small landing legs on the tanks. There's also a 16-S antenna on top of the probe core, you can see it sticking out of the reaction wheel.

Armstrong Memorial- 0.745N, 22.725E. I landed on the second stage because there was still plenty of fuel left in it.

Re-entering directly from the Munar return orbit got a bit hot, the landing legs and solar panels didn't survive but everything else was fine.

And by complete coincidence entirely intentionally, I landed a mere 60km from the KSC.

This design could easily carry a science payload (experiment return unit with some experiments on it, but not a materials bay) to do a return trip; I just made a proof of concept version quickly.

 

 

3 hours ago, Streetwind said:

 

Hmmm. I see. Alright then, here's some very basic rocketry tips:

1.) Train your pilots. If you are playing with the Kerbal level-up experience system enabled (meaning, Kerbals are not five-star by default), then you want to send a few pilots into Kerbin orbit and back before you head anywhere else. Orbit around Kerbin is enough to get them to level 1, at which point they learn "SAS Hold Prograde". That means you can tell your Kerbal pilot to help you fly by trying to always keep the nose pointed in the direction of travel. You will find this invaluable while launching. There are also probe cores that have this ability, but unless you are playing sandbox mode, you have to put in some research effort to unlock them.

2.) "The golden rule of rocketry": heavy stuff at the front, draggy stuff at the back. Think of an arrow. The compact, pointy metal head is right at the tip. The light feathers that catch a lot of air are at the back. In technical terms, the center of mass is ahead of the center of pressure. This causes passive stability. A well-built, passively stable rocket can fly to orbit without turning on SAS and without touching the steering keys - only via managing the throttle. Though admittedly, in practical application not many player-built ships will be quite that stable, because payloads tend to be light and fuel tends to be heavy, which makes it hard to achieve this perfect distribution. Rather than taking this rule too far, take its opposite, and keep it in your mind as what not to do. Do not put wings or fins on the nose of your rocket, for example. And when you find yourself with a rocket that will not fly straight no matter what, then think of this rule when trying to find the reason.

3.) Single-size designs. A major source of instability is flexing joints, and few joints flex more than stepping down to a smaller part size in the middle of a stack and then stepping up again. This also causes drag, by the way, which (as we just learned) is bad if it happens towards the front of the rocket. As you progress in the game, you will gain parts (service bays, fairings, and engine plates) that allow you to shield smaller parts in the envelope of a larger one.

4.) Single-stack designs. Another thing that wants to flex like Dwayne Johnson hopped up on caffeine is a small radial decoupler carrying a large side booster producing massive thrust. You can use struts to try and fortify such boosters, or you can turn on advanced tweakables and simply magick away joint flexing via rigid attachment and autostrutting (if you do not feel cheaty by doing so), but you can also simply not have the problem in the first place by building your rocket without large radially attached boosters. The main limitation you have here is the thrust output of the launch stage engine. However, it is still easily possible to reach orbit on a single-stack, 1.25m size rocket. It is also possible to perform a Mun flyby and return to Kerbin on a single-stack, 1.25m rocket. Though to pull that off, you may need to get some practice in the next item on this list.

5.) Downsizing. Contrary to what you may think, bigger isn't always better. You will learn about this as you get deeper into the game (the keyword is "Delta-V"), but for now, what you need to understand is: how far a rocket can go does not directly scale with its size. The only thing that counts is the mass of the fuel you carry compared to the mass of "not-fuel" you carry. And no matter if your rocket is 10 meters in diameter or just 1 meter - if this ratio is the same, then both rockets will fly the same distance. So the takeaway should be: you must minimize everything that is "not-fuel". Take the fewest number of parts that are not fuel tanks as is possible. And if you have multiple parts that can fulfill a certain job you need done, pick the one that weighs the least - unless this causes other problems, such as having the wrong size. Besides helping with going further, this also helps with rocket building in general - if your rocket is light enough, you do not need extra boosters to make it move! And without extra boosters, you don't get flexing decoupler joints, which means your rocket won't go out of control on ascent...

To illustrate my point, let me show you the rocket I used for my initial Mun flyby the last time I played Career (well, Science mode, actually):

  Reveal hidden contents

From the top down, that is: a MK-16 parachute, a MK1 command pod, a 1.25m service bay, a TD-12 decoupler, two SC-9001 "Sciene Jr." bays, a FL-T200 tank, a FL-T400 tank, a LV-909 "Terrier" engine, another decoupler, another four FL-T400 tanks, and finally a LV-T30 "Reliant" engine. Inside the service bay, there are two mystery goo containers, two thermometers, two barometers, and two Z-100 batteries.

Super simple. No radial boosters. No size mismatches. No struts. No advanced tweakables shenanigans. The whole thing weighs just 15.4 tons and contains just 23 parts, 8 of which are science instruments. It can be built and launched in career mode without needing any building upgrades whatsoever, and no tech tree node more expensive than 45 science. It actually has a healthy surplus of fuel for the Mun flyby mission - you could technically slim it down a little more still, but then again, you can never go wrong with some safety margin.

It is not 100% passively stable, but perhaps 99%. Adding four basic fins to the bottom will make it perfectly passively stable - a bit too stable for my tastes even, so stable that it becomes hard to make it turn in the lower atmosphere. Which is why I prefer it without fins.

A lot to digest in these two posts!  Thanks. I’m in sandbox mode do I still have to train my Kerbals?

 

I had no idea which way the hatch faced mattered in how I took off!  

 

 

 

[Streetwind]

1 minute ago, ADKGuy said:

I’m in sandbox mode do I still have to train my Kerbals?

Not unless you intentionally changed your difficulty settings to make it so. In default sandbox mode, Kerbal experience is disabled, and all Kerbals are maximum level all the time.

In this case, you have even more SAS modes available to you when you have a pilot on board (or use one of the high-end probe cores). When you press T, these modes appear as little red circles on the left of the navball. You can click them to switch between them.

[jimmymcgoochie]

2 hours ago, ADKGuy said:

I had no idea which way the hatch faced mattered in how I took off!  

It doesn't matter in the strictest sense, but it makes it much easier to figure out what way you're going. The way the rocket is oriented in the VAB is exactly the same as it will appear on the launchpad; the VAB doors face east towards the pad and you want to turn east to gain orbital velocity, so it makes sense to point in that direction.

Most real crewed rockets used to/still do take off with the crew hatch facing towards their direction of travel after they start turning because a) if the crew can see the ground out of that window instead of the sky they know to hit that big red ABORT button, b) old rockets had very limited computing capacity (I've heard it said that Apollo 11's service module and lander computers combined would be outclassed by an old pocket calculator, and not even a scientific one either) so a straight forward pitch program was easier to compute and c) you're pulling up as you climb, a procedure familiar to pilots (and many astronauts during the space race were previously military or test pilots).

[ADKGuy]

10 hours ago, Streetwind said:

Not unless you intentionally changed your difficulty settings to make it so. In default sandbox mode, Kerbal experience is disabled, and all Kerbals are maximum level all the time.

In this case, you have even more SAS modes available to you when you have a pilot on board (or use one of the high-end probe cores). When you press T, these modes appear as little red circles on the left of the navball. You can click them to switch between them.

I have all of them available and have toyed with them a bit. 
 

I did manage to get a Mun encounter a couple of times but then had no idea what I was looking at or what to do with all the stuff that popped up on the map screen and by then I didn’t have enough fuel to make many burns anyway. 

7 hours ago, jimmymcgoochie said:

It doesn't matter in the strictest sense, but it makes it much easier to figure out what way you're going. The way the rocket is oriented in the VAB is exactly the same as it will appear on the launchpad; the VAB doors face east towards the pad and you want to turn east to gain orbital velocity, so it makes sense to point in that direction.

Most real crewed rockets used to/still do take off with the crew hatch facing towards their direction of travel after they start turning because a) if the crew can see the ground out of that window instead of the sky they know to hit that big red ABORT button, b) old rockets had very limited computing capacity (I've heard it said that Apollo 11's service module and lander computers combined would be outclassed by an old pocket calculator, and not even a scientific one either) so a straight forward pitch program was easier to compute and c) you're pulling up as you climb, a procedure familiar to pilots (and many astronauts during the space race were previously military or test pilots).

Good to know. Yeah, it’s crazy to think how much technology has changed. Look at SpaceX’s Crew Dragons touch screens. I’d love to hear Buzz’s reaction on that. 
 

Met him at the Air and Space Museum years ago and got his Mars book signed. Pretty cool experience.