[1.9-1.10] Throttle Controlled Avionics

[Blackline]

I actually want something different, TCA should ONLY use engine thrust, IF reaction wheels are fully engaged, to save fuel.

[orthi]

Hi. I love this great mod... I have a question though. Landing with stock combustion rockets works a treat. If I use KSP Interstellar Extended Nuclear rockets however the spacecraft will always crash

It will deorbit just fine, then coast to its correction burn just fine, so it is right on target. Then however it never decelerates. The mod says, there is not enough delta V available, will decelerate as much as I can. However it will do nothing of the sort. It will crash without raising the throttle again, eventhough I sit on 9k dV in that particular case and my Closed Gas Reactor Engine is operational. It must be, because the mod already deorbited and target adjusted with it

Does this have something to do with KSPI's adjusting thrust and is there a way around it, so this great mod can autoland rockets with these nuclear engines?

[Crabman]

1 hour ago, orthi said:

It will deorbit just fine, then coast to its correction burn just fine, so it is right on target. Then however it never decelerates. The mod says, there is not enough delta V available, will decelerate as much as I can.

I had this problem with Karibou (USI) engines and also with the stock Mk-55 "Thud". I deorbited fine, but I think it took too long to kill horizontal velocity because of low TWR and with also slow turning to correct error it just throttle full again and lost control. I don't even know how to report this behaviour. Is there any way to do a less agressive landing, with more margin to turn and correct error?

Thanks for this mod anyway, it's very good!

[orthi]

1 hour ago, Crabman said:

I had this problem with Karibou (USI) engines and also with the stock Mk-55 "Thud". I deorbited fine, but I think it took too long to kill horizontal velocity because of low TWR and with also slow turning to correct error it just throttle full again and lost control. I don't even know how to report this behaviour. Is there any way to do a less agressive landing, with more margin to turn and correct error?

Thanks for this mod anyway, it's very good!

Well in my case it could also be the different fuel, so that the mod looks for the "default" fuel and sees there is none there. In KSPI you can change the fuel for your engines and with that the impulse and thrust. Maybe this is also a problem. And then it would be clear that it says not enough dV, because I have none of the default fuel on board.

I will try to see if the thud also fails on me...

[Seeker89]

10 hours ago, g_BonE said:

Now the following problem / question:
In my ongoing 1.2 career and a freshly started career all the command modules show "TCA: unavailable" despite having a fuel tank, engine and RCS on the craft and the TCA tech is researched completely. Thus the TCA button only opens the manual and im unable to program engine groups or macros.

Im running quite a few mods too but on 1.1.3 with almost the same mods TCA worked just as expected. Do You have an idea what might cause this issue? Is there anything im missing or misunderstood? Is there a way to enable the full TCA window in the editor without the requirements (engine, rcs, etc.) ?

 

I'm kinda having that problem.. all command modules show "TCA: unavailable", but all modules are unlocked and it all works from what I use.. I thought it was because of the MM I made up to unlock at start.

 

EDIT: Status in the manuel says that it's all on... btw

Edited October 19, 2016 by Seeker89

[allista]

3 hours ago, orthi said:

Hi. I love this great mod... I have a question though. Landing with stock combustion rockets works a treat. If I use KSP Interstellar Extended Nuclear rockets however the spacecraft will always crash

It will deorbit just fine, then coast to its correction burn just fine, so it is right on target. Then however it never decelerates. The mod says, there is not enough delta V available, will decelerate as much as I can. However it will do nothing of the sort. It will crash without raising the throttle again, eventhough I sit on 9k dV in that particular case and my Closed Gas Reactor Engine is operational. It must be, because the mod already deorbited and target adjusted with it

Does this have something to do with KSPI's adjusting thrust and is there a way around it, so this great mod can autoland rockets with these nuclear engines?

Thanks for the report.

Well, this is definitely not normal. I would guess it has something to do with the calculation of a total fuel mass available to the ship. I don't know how KSPIE nukes work, never played with the mod.

I will investigate the matter. Thank you for the report!

[allista]

2 hours ago, Crabman said:

I had this problem with Karibou (USI) engines and also with the stock Mk-55 "Thud". I deorbited fine, but I think it took too long to kill horizontal velocity because of low TWR and with also slow turning to correct error it just throttle full again and lost control. I don't even know how to report this behaviour. Is there any way to do a less agressive landing, with more margin to turn and correct error?

Thanks for this mod anyway, it's very good!

I don't know what to suggest, except to change the ship's design. Landing from orbit is one of the most sophisticated autopilots I've created so far; it has many safety checks and alternate scenarios, many realtime corrections to adapt to the situation. But you can't be less "agressive": in orbit a ship has so much energy, that more "gentle" approach would mean huge fuel expenditure because of the engines that constantly work against gravity. And control authority (especially on atmospheric worlds) is a must.

Still, I would not (ever) state that the autopilot is perfect. So I would appreciate if you share the .craft file of your lander with the stock "Thud" engine; and a more verbose description of the situation where it has crashed. So that I could investigate.

40 minutes ago, Seeker89 said:

I'm kinda having that problem.. all command modules show "TCA: unavailable", but all modules are unlocked and it all works from what I use.. I thought it was because of the MM I made up to unlock at start.

EDIT: Status in the manuel says that it's all on... btw

Very strange! All on and all unlocked including the "Throttle Control Avionics Subsystem"? Please, check the R&D and ensure that not only nodes are unlocked, but the subsystem is purchased. In stock tech tree it is located at "Stability" node.

And please share the log if all checks out and TCA is still unavailable.

[FirroSeranel]

Hey @allista, is there any way to have TCA do some basic TWR per stage and dV or fuel remaining per stage calculations, so it can do a better job of dealing with staged launches?

I'm having an issue where my sustainer stage gets me to the target Ap, with just a tiny bit of fuel left. At that point, with that much fuel already spent, the craft's TWR is like, 4.5 or something. But then when it goes to make a circularization burn, it calculates the node using the 4.5 TWR, but that only has a few seconds of fuel left, so then when it switches to, say, a 0.8 TWR vacuum engine, it fails to circularize and burns up in an unplanned reentry.

None of the autopilots I've used or seen have been able to do this, including MechJeb. If TCA could do this sort of (mildly) predictive analysis, and adjust burn times for nodes according to actual future TWR predictions across stages, it would be a total first.

[allista]

1 minute ago, FirroSeranel said:

Hey @allista, is there any way to have TCA do some basic TWR per stage and dV or fuel remaining per stage calculations, so it can do a better job of dealing with staged launches?

I'm having an issue where my sustainer stage gets me to the target Ap, with just a tiny bit of fuel left. At that point, with that much fuel already spent, the craft's TWR is like, 4.5 or something. But then when it goes to make a circularization burn, it calculates the node using the 4.5 TWR, but that only has a few seconds of fuel left, so then when it switches to, say, a 0.8 TWR vacuum engine, it fails to circularize and burns up in an unplanned reentry.

None of the autopilots I've used or seen have been able to do this, including MechJeb. If TCA could do this sort of (mildly) predictive analysis, and adjust burn times for nodes according to actual future TWR predictions across stages, it would be a total first.

It's not that simple to implement, but I'll add this to the list. Thanks for the suggestion!

[Blackline]

If you don't mind, ill repost this, since it seems it has been overlooked :

Quote: Because in Orbit there's no notion of vertical speed.

I don't understand what you mean by this, or why it should prevent using vsc in Orbit. But this might hit another issue I have: the prograde commmand does not follow my selection (surface or Orbit (or even target)) but rather decides by itself, what prograde is to be used. Are there any threshholds for that behavior change? Wouldn't it make sense to couple it to the users selection?

[FirroSeranel]

33 minutes ago, Blackline said:

If you don't mind, ill repost this, since it seems it has been overlooked :

Quote: Because in Orbit there's no notion of vertical speed.

I don't understand what you mean by this, or why it should prevent using vsc in Orbit. But this might hit another issue I have: the prograde commmand does not follow my selection (surface or Orbit (or even target)) but rather decides by itself, what prograde is to be used. Are there any threshholds for that behavior change? Wouldn't it make sense to couple it to the users selection?

 

 

 

In orbit, while there is such a thing as a vertical component of velocity relative to the parent body's center (or surface), the effects of thrusting are non-intuitive. For example, if you were descending at 20 m/s and told TCA that you want to descend at 10 instead, and it points the engines radially inward and thrusts... you won't deorbit at all. You'll actually rotate your orbit around your current location to increase orbital altitude in front of you and decrease it behind you.

Instead, to deorbit, you thrust retrograde to slow down.

Thus "vertical speed" is only really a relevant concept when you're suborbital, and thrusting down slows down your descent instead of doing counterintuitive things to your orbit.

Not to mention, trying to do a velocity-constant deorbit would be wildly, untenably fuel-inefficient. You can deorbit and land on the Mun for about 800 m/s with a suicide burn at the end. Or... you could easily spend 10,000 m/s doing a controlled 10 m/s descent, which is more dV than you can possibly have with stock engines.

May I ask what exactly it is you want to -do- using vertical speed control in orbit?

Edited October 19, 2016 by FirroSeranel

[g_BonE]

about the tca being unavailable In vab/sph : once I get home from work I will post a savegame (contains the mod list) and maybe some screenshots / more details here. 

[Blackline]

5 hours ago, FirroSeranel said:

In orbit, while there is such a thing as a vertical component of velocity relative to the parent body's center (or surface), the effects of thrusting are non-intuitive. For example, if you were descending at 20 m/s and told TCA that you want to descend at 10 instead, and it points the engines radially inward and thrusts... you won't deorbit at all. You'll actually rotate your orbit around your current location to increase orbital altitude in front of you and decrease it behind you.

Instead, to deorbit, you thrust retrograde to slow down.

Thus "vertical speed" is only really a relevant concept when you're suborbital, and thrusting down slows down your descent instead of doing counterintuitive things to your orbit.

Not to mention, trying to do a velocity-constant deorbit would be wildly, untenably fuel-inefficient. You can deorbit and land on the Mun for about 800 m/s with a suicide burn at the end. Or... you could easily spend 10,000 m/s doing a controlled 10 m/s descent, which is more dV than you can possibly have with stock engines.

May I ask what exactly it is you want to -do- using vertical speed control in orbit?

You may ask :-) at first thanks for the information, but that was not what I intend to do. But I do not fully agree. It wont make much sense at first glance, im with you on that side, but setting a vertical speed control of -300m/s would definitely deorbit your craft. You can change the allowed vsc range in the user config file.

I want to start in a 10x10 Orbit around mun and start a retro burn with vsc set to 0m/s to realize a Constant Altitude Burn (CAS) . And slowly increase the allowed the vsc until it ends in a common suizide burn.

[g_BonE]

alright, here is an uploaded savegame and logfile. i just created a new game and cheated in some science points to purchase all TCA related stuff from the tech tree. also created a quick craft which has tank, engine and RCS.

http://www104.zippyshare.com/v/NpPDJCMW/file.html

Also included some screenshot snippets demonstrating the problem. Hope it helps figuring out why TCA does not activate properly in the editors.

Additionally i wanted to state that TCA works flawlessly in flight, i.e. i can run all the modules when im at the launchpad.

 

edit: found this in the logs, dont know if this might be the culprit?

[EXC 19:22:28.654] NullReferenceException: Object reference not set to an instance of an object
	AT_Utils.Utils.PartIsPurchased (System.String name)
	ThrottleControlledAvionics.TCAModulesDatabase.ModuleAvailable (System.Type m)
	ThrottleControlledAvionics.EnginesProfileEditor.Awake ()
	UnityEngine.GameObject:AddComponent(Type)
	AddonLoader:StartAddon(LoadedAssembly, Type, KSPAddon, Startup)
	AddonLoader:StartAddons(Startup)
	AddonLoader:OnLevelLoaded(Int32)
	AddonLoader:OnSceneLoaded(Scene, LoadSceneMode)
	UnityEngine.SceneManagement.SceneManager:Internal_SceneLoaded(Scene, LoadSceneMode)

 

Edited October 19, 2016 by g_BonE

[allista]

2 hours ago, g_BonE said:

alright, here is an uploaded savegame and logfile. i just created a new game and cheated in some science points to purchase all TCA related stuff from the tech tree. also created a quick craft which has tank, engine and RCS.

http://www104.zippyshare.com/v/NpPDJCMW/file.html

Also included some screenshot snippets demonstrating the problem. Hope it helps figuring out why TCA does not activate properly in the editors.

Additionally i wanted to state that TCA works flawlessly in flight, i.e. i can run all the modules when im at the launchpad.

edit: found this in the logs, dont know if this might be the culprit?

[EXC 19:22:28.654] NullReferenceException: Object reference not set to an instance of an object
	AT_Utils.Utils.PartIsPurchased (System.String name)
	ThrottleControlledAvionics.TCAModulesDatabase.ModuleAvailable (System.Type m)
	ThrottleControlledAvionics.EnginesProfileEditor.Awake ()
	UnityEngine.GameObject:AddComponent(Type)
	AddonLoader:StartAddon(LoadedAssembly, Type, KSPAddon, Startup)
	AddonLoader:StartAddons(Startup)
	AddonLoader:OnLevelLoaded(Int32)
	AddonLoader:OnSceneLoaded(Scene, LoadSceneMode)
	UnityEngine.SceneManagement.SceneManager:Internal_SceneLoaded(Scene, LoadSceneMode)

 

Oh, THIS is definitely the culprit! Thank you for digging this out.

Looks like some hidden KSP-1.2 incompatibility, but I'll know for sure when I'm in the code again.

19 hours ago, orthi said:

Hi. I love this great mod... I have a question though. Landing with stock combustion rockets works a treat. If I use KSP Interstellar Extended Nuclear rockets however the spacecraft will always crash

It will deorbit just fine, then coast to its correction burn just fine, so it is right on target. Then however it never decelerates. The mod says, there is not enough delta V available, will decelerate as much as I can. However it will do nothing of the sort. It will crash without raising the throttle again, eventhough I sit on 9k dV in that particular case and my Closed Gas Reactor Engine is operational. It must be, because the mod already deorbited and target adjusted with it

Does this have something to do with KSPI's adjusting thrust and is there a way around it, so this great mod can autoland rockets with these nuclear engines?

Ah... tried to make something up with KSPIE. Never played with the thing, so couldn't make heads or tails of it!

Would you be so kind as to share the .craft file (or the save file) with the problematic ship? 

[FirroSeranel]

8 hours ago, Blackline said:

You may ask :-) at first thanks for the information, but that was not what I intend to do. But I do not fully agree. It wont make much sense at first glance, im with you on that side, but setting a vertical speed control of -300m/s would definitely deorbit your craft. You can change the allowed vsc range in the user config file.

I want to start in a 10x10 Orbit around mun and start a retro burn with vsc set to 0m/s to realize a Constant Altitude Burn (CAS) . And slowly increase the allowed the vsc until it ends in a common suizide burn.

 

Ah. Well, that's... yeah, not really gonna work at all for the deorbit burn.

Setting a vertical speed control of -300 m/s -might- deorbit your craft (assuming radial thrust, which is what TCA assumes for pure vertical speed control). Or it might decrease your altitude, but leave you skimming along above the surface going so fast your engines aren't powerful enough to maintain the -300 m/s anymore. You could very well reach escape velocity, perhaps even of Kerbin's SoI! In fact, one trick you can use during gravity slingshots is basically exactly that: set your Pe as low as you can get it without impacting surface features, then right at Pe you burn radially in toward the body as hard as you can. It increases the "bend" around the body, thus changing the exit angle, allowing you to do a more extreme velocity and/or direction change through the gravity assist.

Even if it did deorbit your craft, by the time you were at low altitude, you'd still be traveling at orbital horizontal velocity, -plus- the 300m/s vertical velocity, and come in screaming fast with at least a 1200 m/s suicide burn required at the end to avoid crashing.

Basically, unless I'm missing something... and I'm trying not to be a dick about it... what you're trying to do just isn't how space flight works. Trying to force orbital mechanics to obey a constant-velocity descent means spending a -lot- of fuel to change the natural Keplerian deorbit trajectory into something radically different.

A constant rate of descent is a great thing for airplanes. Not so much for spaceships landing on bodies without atmosphere.

The most fuel-efficient deorbit is one that puts your Pe as close to tangential to the ground as you can make it and still clear surrounding terrain, followed by a suicide burn timed perfectly to reach zero velocity along all three axes just as you kiss the ground. That is, however, -extremely- dangerous, which is why the Apollo lander, for example, used a step-wise descent profile, starting with a retrograde deorbit burn, and then a series of (I believe three) smaller burns to reduce horizontal velocity and keep vertical velocity from getting too extreme. It cost them more fuel, but gave them a much greater safety margin in case things went wrong.

All that aside... whether because the algorithms to transition from a zero-vertical-velocity orbit to a constant-descent deorbit are too complex, or simply because it's so wildly non-optimal that he just didn't want people to have the temptation, Allista turned the button off. *shrugs* Not sure what else to tell ya.

[FirroSeranel]

@allista, I have another request.

I would like the ability to have a macro trigger an action group. I have mods with engines that can switch from hover to flight mode, like the Harrier, but no way to trigger the transition as part of a macro. Would this be difficult to add?

[FirroSeranel]

Hahaha! I made a Harrier! It totally works!

[g_BonE]

@allista, thanks for looking in to this! and thanks again for this great mod! using it mainly for VTOL and auto waypoint navigation on kerbin currently. it's amazing what TCA makes possible and controllable. thanks again and keep it up!

[allista]

4 hours ago, FirroSeranel said:

@allista, I have another request.

I would like the ability to have a macro trigger an action group. I have mods with engines that can switch from hover to flight mode, like the Harrier, but no way to trigger the transition as part of a macro. Would this be difficult to add?

Thanks for the suggestion. Will do! 

[Blackline]

9 hours ago, FirroSeranel said:

Ah. Well, that's... yeah, not really gonna work at all for the deorbit burn.

Setting a vertical speed control of -300 m/s -might- deorbit your craft (assuming radial thrust, which is what TCA assumes for pure vertical speed control). Or it might decrease your altitude, but leave you skimming along above the surface going so fast your engines aren't powerful enough to maintain the -300 m/s anymore. You could very well reach escape velocity, perhaps even of Kerbin's SoI! In fact, one trick you can use during gravity slingshots is basically exactly that: set your Pe as low as you can get it without impacting surface features, then right at Pe you burn radially in toward the body as hard as you can. It increases the "bend" around the body, thus changing the exit angle, allowing you to do a more extreme velocity and/or direction change through the gravity assist.

Even if it did deorbit your craft, by the time you were at low altitude, you'd still be traveling at orbital horizontal velocity, -plus- the 300m/s vertical velocity, and come in screaming fast with at least a 1200 m/s suicide burn required at the end to avoid crashing.

Basically, unless I'm missing something... and I'm trying not to be a dick about it... what you're trying to do just isn't how space flight works. Trying to force orbital mechanics to obey a constant-velocity descent means spending a -lot- of fuel to change the natural Keplerian deorbit trajectory into something radically different.

A constant rate of descent is a great thing for airplanes. Not so much for spaceships landing on bodies without atmosphere.

The most fuel-efficient deorbit is one that puts your Pe as close to tangential to the ground as you can make it and still clear surrounding terrain, followed by a suicide burn timed perfectly to reach zero velocity along all three axes just as you kiss the ground. That is, however, -extremely- dangerous, which is why the Apollo lander, for example, used a step-wise descent profile, starting with a retrograde deorbit burn, and then a series of (I believe three) smaller burns to reduce horizontal velocity and keep vertical velocity from getting too extreme. It cost them more fuel, but gave them a much greater safety margin in case things went wrong.

All that aside... whether because the algorithms to transition from a zero-vertical-velocity orbit to a constant-descent deorbit are too complex, or simply because it's so wildly non-optimal that he just didn't want people to have the temptation, Allista turned the button off. *shrugs* Not sure what else to tell ya.

1) you did misinterpret me. I do NOT want to deorbit via vsc only. What I said, that it IS possible to deorbit via vsc, you said it isnt.

2) suizide burn is NOT the most efficient way to dorbit. See https://m.reddit.com/r/KerbalSpaceProgram/comments/2zoeqf/most_efficient_way_to_land_suicide_burn_good/

3) linking the availability of vsc to the orbit status is IMHO a unnecessary limitation. I am just asking for a way to enable vsc in all situations, for example via user config

 

[Bit Fiddler]

Well I have been looking at this mod for a year or more now, and keep telling myself I need to use it.  So I finally took the plunge into the VTOL soup (no Kerbals were put in a blender to make this soup...)  any way  as I get working on VTOL design, I find myself in need of Intake Air powered RCS...  I see B9 has some, but does anybody know of any other mods offering intake air powered RCS?

 

it can be    intake air + EC = compressed air --> RCS  or requiring an active engine of some sort etc.   I am not looking for a "free ride" I just need to use compressed air for RCS so I do not need to carry limited supplies in a tank such as Monoprop.

[Denko666]

15 minutes ago, Bit Fiddler said:

Well I have been looking at this mod for a year or more now, and keep telling myself I need to use it.  So I finally took the plunge into the VTOL soup (no Kerbals were put in a blender to make this soup...)  any way  as I get working on VTOL design, I find myself in need of Intake Air powered RCS...  I see B9 has some, but does anybody know of any other mods offering intake air powered RCS?

 

it can be    intake air + EC = compressed air --> RCS  or requiring an active engine of some sort etc.   I am not looking for a "free ride" I just need to use compressed air for RCS so I do not need to carry limited supplies in a tank such as Monoprop.

Quiztech aeropack has cute little air powered rcs ports. 

[Bit Fiddler]

 

1 minute ago, Denko666 said:

Quiztech aeropack has cute little air powered rcs ports. 

ah this is the one I was looking for actually.  I love the Mk2 and I knew I had a pack of Mk2 stuff that had some in it...   thanks a bunch

[FirroSeranel]

17 minutes ago, Blackline said:

1) you did misinterpret me. I do NOT want to deorbit via vsc only. What I said, that it IS possible to deorbit via vsc, you said it isnt.

2) suizide burn is NOT the most efficient way to dorbit. See https://m.reddit.com/r/KerbalSpaceProgram/comments/2zoeqf/most_efficient_way_to_land_suicide_burn_good/

3) linking the availability of vsc to the orbit status is IMHO a unnecessary limitation. I am just asking for a way to enable vsc in all situations, for example via user config

 

 

The gravity turn is actually what I described, not a "halt in space then drop to suicide burn". That's absurdly wasteful, I wouldn't even have ever considered it!

But yes, the CAS described there is certainly better than a vertical drop, you're right. A gravity turn is better still, however. That post isn't quite right about the lunar lander though, it actually used a step-wise deorbit, that was similar to the gravity turn, but safer, since it doesn't rely on an angled suicide burn that kills horizontal and vertical velocity just as you touch the ground.

(To be clear, a suicide burn doesn't imply a vertical velocity vector, just a burn at the last possible second to stop all motion just as you touch the ground.)

It's basically the same thing as the different ascent profiles.

1 in that Reddit post is the same thing as thrusting vertically to Ap, then horizontally to circularize, and is the least-efficient in vacuum, and only efficient in atmosphere for -extremely- non-aerodynamic craft, like launching a giant curved section of space station or something.

2 in the Reddit is basically what MechJeb and TCA call a "gravity turn", though it actually isn't. It's much better than 1, but still less efficient than a real gravity turn.

But yes, I did misunderstand what you were wanting to do. You never mentioned that you would burn retrograde to lower your Pe first.

If you re-read what I wrote, you'll see that that's exactly what I said, I just phrased it as "get your Pe as close to the surface as you can without risking impacting surface features".

I also never said it was impossible to deorbit with vertical thrust only... just not -always- possible, and I then gave an example of a case in which it wouldn't be.

In any case, a gravity turn approach is actually really easy to do in KSP. Just burn retrograde to set your Pe slightly below the ground, so the intercept is slightly beyond where you want to land, then coast down with SAS set to Retrograde in Surface mode (not Orbit mode, this will produce unfortunate results), and burn whenever you're comfortable. You'll probably wind up using exactly the sort of step-wise landing sequence Apollo used, just because it's much safer and less scary than a suicide burn at the end, especially since no mod I've seen yet can properly calculate the timing of a suicide burn that deviates much from a 90° angle.

So... yes, @allista, technically if you allowed VSC in orbit, you'd enable a middle-of-the-road option in terms of efficiency. I'm just not sure why anyone would use it, when the more efficient version is also easier to do.