[1.12.x] Anatid Robotics / MuMech - MechJeb - Autopilot - [2.14.3] [4th March 2023]

[Aelfhe1m]

4 hours ago, StickyScissors said:

Anybody know of a decent launch profile/setup for KScale 6.4? i cant seem to get it right

It depends on your launchers staging set-up, especially the TWR and burn-time per stage.

I've been using Rescale 6.4x for my latest game and for high TWR fast-to-orbit launchers I use 40% turn shape and 90km turn end altitude.

Launchers with low TWR final stages need to be lofted more typically with a 50% or 55% turn shape and 100km turn end altitude. I'll also monitor the time to apoapsis before and during the final stage and may need to adjust final flight path angle (possibly several times) to keep the time within a suitable range.

dV to a 150 km to 200 km parking orbit ranges from about 6700 m/s to > 8000 m/s depending on specific set-up. I tend to optimise for price rather than lowest dV.

EDIT: Note I'm playing with SMURFF and stock aero (no FAR).

Edited November 22, 2017 by Aelfhe1m

[jrodriguez]

Hi all,

I'm experiencing an annoying issue when landing using Mechjeb on Earth.  The problem is that Mechjeb seems to be trying to "land" when the rocket still at 200-300 meters altitude (of course causing a catastrophic end lol)

Have you ever seen something similar? 

[Loren Pechtel]

7 minutes ago, jrodriguez said:

Hi all,

I'm experiencing an annoying issue when landing using Mechjeb on Earth.  The problem is that Mechjeb seems to be trying to "land" when the rocket still at 200-300 meters altitude (of course causing a catastrophic end lol)

Have you ever seen something similar? 

Catastrophic?

In my experience the behavior you describe is normal and desirable.  When you attempt to land at a target MechJeb actually aims for a point that in my experience is 500m above the target.  Once it reaches that point it drops the rocket straight down and then burns to reach a soft touchdown.  This is a lot safer than doing a suicide burn that's prone towards leaving inaccuracies that cause the rocket to land not straight up or with a horizontal velocity component like tends to happen when you use the land anywhere function.

[jrodriguez]

1 minute ago, Loren Pechtel said:

Catastrophic?

In my experience the behavior you describe is normal and desirable.  When you attempt to land at a target MechJeb actually aims for a point that in my experience is 500m above the target.  Once it reaches that point it drops the rocket straight down and then burns to reach a soft touchdown.  This is a lot safer than doing a suicide burn that's prone towards leaving inaccuracies that cause the rocket to land not straight up or with a horizontal velocity component like tends to happen when you use the land anywhere function.

uhmm Maybe the problem is then related with the "soft" touchdown part. My rocket has like TWR=2 aprox and due to the engine response speed, it takes like 1-2 seconds to have full thrust on the engines. The problem then is that Mechjeb is applying full throttle too late for my rocket .

[MaxwellsDemon]

1 hour ago, jrodriguez said:

Hi all,

I'm experiencing an annoying issue when landing using Mechjeb on Earth.  The problem is that Mechjeb seems to be trying to "land" when the rocket still at 200-300 meters altitude (of course causing a catastrophic end lol)

Have you ever seen something similar? 

I've been having multiple problems with the landing module of MechJeb since the 1.3.1 upgrade.   

I assume we'll need to wait for another dev build when sarbian has time to address it.

[sarbian]

5 minutes ago, MaxwellsDemon said:

when sarbian has time to address it.

This is the main problem currently. Time and will.

[Loren Pechtel]

1 hour ago, jrodriguez said:

uhmm Maybe the problem is then related with the "soft" touchdown part. My rocket has like TWR=2 aprox and due to the engine response speed, it takes like 1-2 seconds to have full thrust on the engines. The problem then is that Mechjeb is applying full throttle too late for my rocket .

It sounds like the real problem is you're using a non-stock engine that takes time to throttle up.  MechJeb assumes it can do what it wants with the engine's throttle.  I have no idea of a solution other than flying the last part of the landing manually.  Better Burn Time will give you a pretty good estimate of the suicide burn time, light it a few seconds early to deal with the throttle delay.

[jrodriguez]

7 minutes ago, MaxwellsDemon said:

I've been having multiple problems with the landing module of MechJeb since the 1.3.1 upgrade.   

I assume we'll need to wait for another dev build when sarbian has time to address it.

Well. In my case I still on KSP 1.3 (with RO/RSS mods suite)

[MaxwellsDemon]

Well, in the meantime, it's got me practicing my manual landings, anyway.  But it's a long way from pinpoint accuracy.  

[jrodriguez]

Hi @sarbian

I was trying to build Mechjeb2 from VS but the sln inside the zip folder seems to be pretty outdated. I'm going to try to fix it adding and removing the files but I thought that it would be nice to have it updated for compilation on Windows+VS dev enviroments.

 

[Ed Oaf]

This is the most excellent mod that exists.

 

The only 'bug' I'm seeing is that sometimes it does not stage and sometimes it does not accelerate time. If you manually stage it carries on as normal, but this isn't optimal. If you manually accelerate time it speeds away as normal. But again not optimal.

Specifically this is happening when I use the ascent guidance on a pretty stock rocket and sometime it doesn't accelerate time when using maneuver planner.

 

I'm using the dev build, I thought it may be better than he release build, but seems to behave the same way.

 

 

Edited November 23, 2017 by Ed Oaf

[pippaf1]

Just installed build 755 and on the hole the landing problem seems to be corrected, there is just one problem every so often it seems to get stack in a coarse correction mode and you have to take manual control, not a biggy once you know about it. You just don’t land where you wanted to.

 

I have noted the staging problem, again not a biggy and it is workable.

[kithylin]

So I have the latest version of kerbal space program, and I have tried both the latest stable version of mechjeb2 from this thread, and the "nightly" version off the dev tracker and.. guess I have to quit playing KSP again because mechjeb is just broken as heck and doesn't do anything correctly. For clarification, mechjeb is the only mod I have installed, all others removed.

Problems:

1.) Ascent guidance turns all ships over to be flat with the horizon at just 30km altitude above the ground. Resulting in both failure to achieve orbit, and most ships burning up in atmosphere. All of said ships I can launch manually and make it in to orbit successfully with no issues.

2.) 80% of the time trying to do in-space maneuvers and like, I was in a flyby trajectory around Ike just now, and told mechjeb to circularize at 0s (now) to establish circular orbit for me. It just sits there at a burn time of 0.0s and doesn't move the ship, doesn't burn anything, doesn't do anything at all. I told it to circularize at the next periapsis and it proceeded to do that correctly with no issues though.

3.) Landing doesn't work. From a 100km circular orbit, I tried to land on Ike. Picked a target on the map on the surface, clicked go. As I type this my other computer is sit here indefinitely doing "Performing course correction of about 0.0m/s" and it's apparently trying to land on the opposite side of the moon from where I picked for some reason. Like not even remotely close, 230km off target. ??????????????????

4.) Most space manuvers don't initiate time warp unless I manually warp it a little bit first and then it'll take over.

This is all very stupidly annoying.. and borderline completely unusable for this mod. It used to work fine in 1.2.xxx, what the heck happened with the current version?

Edited November 25, 2017 by kithylin

[maja]

4 hours ago, kithylin said:

1.) Ascent guidance turns all ships over to be flat with the horizon at just 30km altitude above the ground. Resulting in both failure to achieve orbit, and most ships burning up in atmosphere. All of said ships I can launch manually and make it in to orbit successfully with no issues.

2.) 80% of the time trying to do in-space maneuvers and like, I was in a flyby trajectory around Ike just now, and told mechjeb to circularize at 0s (now) to establish circular orbit for me. It just sits there at a burn time of 0.0s and doesn't move the ship, doesn't burn anything, doesn't do anything at all. I told it to circularize at the next periapsis and it proceeded to do that correctly with no issues though.

3.) Landing doesn't work. From a 100km circular orbit, I tried to land on Ike. Picked a target on the map on the surface, clicked go. As I type this my other computer is sit here indefinitely doing "Performing course correction of about 0.0m/s" and it's apparently trying to land on the opposite side of the moon from where I picked for some reason. Like not even remotely close, 230km off target. ??????????????????

4.) Most space manuvers don't initiate time warp unless I manually warp it a little bit first and then it'll take over.

First thing first, you're not helping with your attitude.

1) I don't have problems with ascent guidance in the latest stable (2.6.1) and KSP 1.3.1. Check your flight profile. I have it set to 60km end altitude, end angle 10° and turn shape 45%.

2) Don't do burns at 0s. Give MJ some time to set a node and turn a vessel. 60s works for me everytime.

3) Landing on the opposite side is a problem, but because landing worked in KSP 1.3, something changed in KSP not in MJ.

4) Again, not a problem with the latest stable in my game.

You are free to stop using MechJeb or stop playing at all, but don't blame the mod developer, that something changed in the game and he don't have time to change his mod.

Edited November 25, 2017 by maja

[jrodriguez]

On 23/11/2017 at 7:48 PM, jrodriguez said:

Hi @sarbian

I was trying to build Mechjeb2 from VS but the sln inside the zip folder seems to be pretty outdated. I'm going to try to fix it adding and removing the files but I thought that it would be nice to have it updated for compilation on Windows+VS dev enviroments.

 

@sarbianI've updated the sln on my fork. If you think it is useful I can do a PR to your dev branch. 

A part from that I have also added a couple actions to the Mechjeb part module to allow automatic landing on target and somewhere. Thus, allowing to trigger them using Smart parts mod. 

 

 

[kithylin]

2 hours ago, maja said:

First thing first, you're not helping with your attitude.

1) I don't have problems with ascent guidance in the latest stable (2.6.1) and KSP 1.3.1. Check your flight profile. I have it set to 60km end altitude, end angle 10° and turn shape 45%.

2) Don't do burns at 0s. Give MJ some time to set a node and turn a vessel. 60s works for me everytime.

3) Landing on the opposite side is a problem, but because landing worked in KSP 1.3, something changed in KSP not in MJ.

4) Again, not a problem with the latest stable in my game.

You are free to stop using MechJeb or stop playing at all, but don't blame the mod developer, that something changed in the game and he don't have time to change his mod.

I never had to "Set anything" before with mechjeb. I always just told the auto ascent thing 100km target, corrective steering, auto staging and clicked go and tapped space and launched and it got me in orbit. It doesn't do that anymore, no matter how simple of a ship I make, even a simple 5 part thing from early in the tech tree can't get up there like this with mechjeb. I don't know what "flight profile" is or "end angle" or "turn shape". I'll repeat: I never had to even concern myself with any of that before with previous versions, just clicked button and it went and had orbit. Admittedly I haven't played in a long time since 1.2.xx, and just got in to 1.3.xx and this is my first experience.

And no I did not do a burn at 0s, you are not understanding what I tried to convey so I'll try to be more clear: I had a trajectory where I was 500km from the surface of Ike, but my periapsis was such that if I did not correct it.. I would smash in to the surface. Typically in the past, at such a situation, even at 500km altitude from the target, I would just open mechjeb, click maneuver planner and tell it: circularize, at a set time, 0 seconds (Which means now, which will end up like +17s by the time it turns the ship around to burn). Click execute button and it would circularize me at about 500k, or 400km or at worst 300km, depending how fast I'm going and how steep the descent trajectory is. But it doesn't do that now. In this same situation, I told it circularize at 0s and clicked go and it just sits there and never fires RCS, never turns the ship, never fires anything. I've always done this for over a year with KSP + Mechjeb, it's always worked before.

Latest version of the game from steam, using the latest version of mechjeb posted in the 1st page of this thread. No other mods loaded what so ever.

Edited November 25, 2017 by kithylin

[maja]

23 minutes ago, kithylin said:

I never had to "Set anything" before with mechjeb. I always just told the auto ascent thing 100km target, corrective steering, auto staging and clicked go and tapped space and launched and it got me in orbit. It doesn't do that anymore, no matter how simple of a ship I make, even a simple 5 part thing from early in the tech tree can't get up there like this with mechjeb. I don't know what "flight profile" is or "end angle" or "turn shape". I'll repeat: I never had to even concern myself with any of that before with previous versions, just clicked button and it went and had orbit. Admittedly I haven't played in a long time since 1.2.xx, and just got in to 1.3.xx and this is my first experience.

Click on Edit ascent path (last checkbox in the Ascent Guidance window). There you can change ascent profile.

 

26 minutes ago, kithylin said:

And no I did not do a burn at 0s, you are not understanding what I tried to convey so I'll try to be more clear: I had a trajectory where I was 500km from the surface of Ike, but my periapsis was such that if I did not correct it.. I would smash in to the surface. Typically in the past, at such a situation, even at 500km altitude from the target, I would just open mechjeb, click maneuver planner and tell it: circularize, at a set time, 0 seconds (Which means now, which will end up like +17s by the time it turns the ship around to burn). Click execute button and it would circularize me at about 500k, or 400km or at worst 300km, depending how fast I'm going and how steep the descent trajectory is. But it doesn't do that now. In this same situation, I told it circularize at 0s and clicked go and it just sits there and never fires RCS, never turns the ship, never fires anything. I've always done this for over a year with KSP + Mechjeb, it's always worked before.

Do a radial burn (Radial in/out) to move your periapsis. The best time is after a SOI change, when you will need the least amount of dV. Radial burns rotates your orbital plane and in your case of hyperbolic orbit ending with the very close Ike encounter the radial burn pushes your periapsis up to a fly-by. You need to choose the right radial burn (in or out), so it's usualy trial and error to get the right one from the two.

[LameLefty]

1 hour ago, kithylin said:

And no I did not do a burn at 0s, you are not understanding what I tried to convey so I'll try to be more clear: I had a trajectory where I was 500km from the surface of Ike, but my periapsis was such that if I did not correct it.. I would smash in to the surface. Typically in the past, at such a situation, even at 500km altitude from the target, I would just open mechjeb, click maneuver planner and tell it: circularize, at a set time, 0 seconds (Which means now, which will end up like +17s by the time it turns the ship around to burn). Click execute button and it would circularize me at about 500k, or 400km or at worst 300km, depending how fast I'm going and how steep the descent trajectory is. But it doesn't do that now. In this same situation, I told it circularize at 0s and clicked go and it just sits there and never fires RCS, never turns the ship, never fires anything. I've always done this for over a year with KSP + Mechjeb, it's always worked before.

In that situation, tell Mechjeb's Maneuver Planner to "Change Periapsis" to something like 70km (or whatever your preferred Pe is) in 10 seconds - that give MJ plenty of time to set the node, adjust your vessel for the radial burn and execute. Then tell Maneuver Planner to "Circularize" at periapsis. That's been my basic technique, and it's worked fine since forever in MJ and KSP since 0.19.

[jrodriguez]

I recorded this beautiful video yesterday using Mechjeb for ascent & landing. You might learn something that Mechjeb is capable of - remote ascending & landing:

Mechjeb  can manage my second stage ascending even if it is not the active vessel. And also the final landing of the first stage even if it is not the active vessel. 

 

[sarbian]

3 hours ago, jrodriguez said:

@sarbianI've updated the sln on my fork. If you think it is useful I can do a PR to your dev branch. 

A part from that I have also added a couple actions to the Mechjeb part module to allow automatic landing on target and somewhere. Thus, allowing to trigger them using Smart parts mod. 

 

 

I have left the solution and project file out since I did not really want to push a post build script that would not work for others. Not sure if I should include it...

[MaxwellsDemon]

53 minutes ago, jrodriguez said:

I recorded this beautiful video yesterday using Mechjeb for ascent & landing. You might learn something that Mechjeb is capable of - remote ascending & landing:

Mechjeb  can manage my second stage ascending even if it is not the active vessel. And also the final landing of the first stage even if it is not the active vessel. 

 

I just have to say, that's a great-looking rocket!

[Loren Pechtel]

4 hours ago, kithylin said:

And no I did not do a burn at 0s, you are not understanding what I tried to convey so I'll try to be more clear: I had a trajectory where I was 500km from the surface of Ike, but my periapsis was such that if I did not correct it.. I would smash in to the surface. Typically in the past, at such a situation, even at 500km altitude from the target, I would just open mechjeb, click maneuver planner and tell it: circularize, at a set time, 0 seconds (Which means now, which will end up like +17s by the time it turns the ship around to burn). Click execute button and it would circularize me at about 500k, or 400km or at worst 300km, depending how fast I'm going and how steep the descent trajectory is. But it doesn't do that now. In this same situation, I told it circularize at 0s and clicked go and it just sits there and never fires RCS, never turns the ship, never fires anything. I've always done this for over a year with KSP + Mechjeb, it's always worked before.

This is very inefficient.

As soon as you enter the SOI of your target body do a burn to set the periapsis to your desired orbit.  Do a circularize at periapsis.  Note that if your circularization burn will be very long (low TWR & carrying a lot of velocity) you should do it in two stages--do a circularization burn well clear of the body and then lower it to your desired orbit.  The problem is that MechJeb does it's math assuming the burn is instant, then brackets it around the burn point.  This has an acceptable error margin when the actual result completes in a quite small fraction of an orbit.  However, the closer and longer the burn the greater the amount of orbit completed during the burn and the greater the error--flying it into the planet is quite possible with Nerva-powered interplanetary missions.

[softweir]

4 hours ago, kithylin said:

... Admittedly I haven't played in a long time since 1.2.xx, and just got in to 1.3.xx and this is my first experience...

Unfortunately, a lot has changed in KSP since then. Most significantly, the aerodynamics were adjusted, in consequence of which rockets that were previously stable are now much less stable and vice versa, and that rockets that used to have enough power are now underpowered. Your description of the problems you are getting makes me suspect your old design practices need tweaking. I certainly had to redesign a lot of old rockets after that change came out!

You may find that playing with rocket designs will pay large dividends. Perhaps downloading some designs from The Spacecraft Exchange and seeing how they work might be useful?

I find that most good rocket designs now work without having to play with MechJeb too much. Still, it is worth going back to @maja's post and read through his suggestions, and work your way through the ascent assist until you have mastered them. Those tweaks and adjustments to MechJeb can be oh-so-useful when trying to expand one's repertoire of rocket designs!

Good luck with this! It's frustrating when a good old game gets improved in ways that upset old gameplay habits, but it can be worth persevering.

[kithylin]

3 hours ago, softweir said:

Unfortunately, a lot has changed in KSP since then. Most significantly, the aerodynamics were adjusted, in consequence of which rockets that were previously stable are now much less stable and vice versa, and that rockets that used to have enough power are now underpowered. Your description of the problems you are getting makes me suspect your old design practices need tweaking. I certainly had to redesign a lot of old rockets after that change came out!

You may find that playing with rocket designs will pay large dividends. Perhaps downloading some designs from The Spacecraft Exchange and seeing how they work might be useful?

I find that most good rocket designs now work without having to play with MechJeb too much. Still, it is worth going back to @maja's post and read through his suggestions, and work your way through the ascent assist until you have mastered them. Those tweaks and adjustments to MechJeb can be oh-so-useful when trying to expand one's repertoire of rocket designs!

Good luck with this! It's frustrating when a good old game gets improved in ways that upset old gameplay habits, but it can be worth persevering.

Nope.. I've designed rockets that can totally get up there in orbit on their own if I do it manually. I have one such ship that I've launched and orbited my craft manually multiple times, same craft with no problems, not even difficult or unstable either. Everything's fine. Just mechjeb for unknown reasons can't seem to figure out how to get it up there without flopping over sideways and burning up each time. And to the above post if mechjeb worked correctly, I shouldn't have to "edit my ascent path" or anything like that. In the past we never had to. This is pretty crappy now. I can do it myself, straight up to 8km, over to 90 degrees on the nav ball until 35km altitude, little further over at 50km, and then at the horizon about 70km until apoapsis is reading 100km. Super simple. But that's not what mechjeb tries to do. I don't know why but it starts turning over to the right at 5km off the ground, and ends up at the horizon by 30km altitude, which makes everything go too fast in atmosphere and burn up and splody. 

KSP & Mechjeb used to be a lot of fun and easy to play now it's just.. I don't know, sucky. I think personally it's because mechjeb developers thought "this made the game too easy" and now require us to do "a lot of manual tuning" to make mechjeb automate correctly. They're not doing everything for us like it used to. I know how to orbit myself, it's a tedious bore now. I much rather have mechjeb totally automate it for me, but it doesn't work. I should just open ascent guidance and click corrective steering and set altitude and click button and if the ascent path needs modifying, mechjeb should do that for me and figure it out on it's own. But it doesn't seem to know how anymore. I've tried many different ship designs, editing almost everything I can think of it's just.. really annoying and stupid now and totally -not easy-.

 

I don't want to be editing ascent path and vectors and what ever and all that other BS. I wish folks would understand, in the past we just clicked corrective steering, clicked engage and then launched and it went. We shouldn't have to screw around with anything else ever. If mechjeb worked that's the entire -POINT- of the mod is to automate all of this for us. 

 

Edited November 25, 2017 by kithylin

[sarbian]

Damned, I was found out. It was indeed all a conspiracy so players can Git Gud.

 

Instead of trying to make me intro a Bond villain you could maybe show us the settings you use ? Because I still use MJ default config to fly a Kerbal X to orbit as my basic test and it still does quite fine.

Edited November 25, 2017 by sarbian