Second stage engine activates on lift-off (no, it's not the staging)

[dandrestor]

Hello!

My name is Dan, and this is my first time posting on the forum. I have a question regarding staging.

On some rockets, when I activate the first stage for take-off, it happens that engines from subsequent stages activate as well. My staging is correct, and my 'stage' action group is empty. Is there anything else I should be checking? I can't understand why this is happening.

Thanks for your thoughts!

Dan

[StrandedonEarth]

It would be so much easier to help if you could post a pic or better yet, a .craft file.

[dandrestor]

Thanks, I'm still a little new at this. This is the subject.

At lift-off, the engines from both stages 8 and 5 activate.

Craft file: https://www.dropbox.com/s/h3kgu93lntbhq1a/LEO%20Probe.craft

Thanks!

[Taki117]

I know you said its not the staging, and I don't want to sound rude, but check your staging anyway. KSP staging goes from bottom to top, with higher numbers being lower stages.

[Claw]

Hi! And welcome to the forums.

Pics and craft files definitely help.

Also check the "Staging" action group in the VAB. If you accidentally put an engine in there, then hitting the space bar will cause those engines to activate even if they aren't "officially" in the first stage.

[dandrestor]

No worries, I've dealt myself with PEBKAC many times

I triple-checked. It's not the staging (as far as I can tell). Maybe you guys can see something I don't?

[Justin Kerbice]

Depending on how you build your craft, KSP get confusing and icon engines are more likely to confuse us, when you mouse over the icon, is it the engine you think it is which is highlighted ?

Also, if you mouse over the part, it is the icon you think it is which is highlighted ?

Does the engine are actually on ? (sounds very obvious but with low thrust, engine doesn't produce so much "particles", especially jet engines)

More pics may be needed as well as the craft file.

[dandrestor]

Depending on how you build your craft, KSP get confusing and icon engines are more likely to confuse us, when you mouse over the icon, is it the engine you think it is which is highlighted ?

Also, if you mouse over the part, it is the icon you think it is which is highlighted ?

Does the engine are actually on ? (sounds very obvious but with low thrust, engine doesn't produce so much "particles", especially jet engines)

More pics may be needed as well as the craft file.

Yes, I checked by mousing over the icons. And yes, I'm sure the (second) engine is on, I can see it depleting fuel.

I uploaded the craft file and a pic (post #3).

[Claw]

I downloaded your craft and it appears you have several mods. I'm not running most of those so I can't check it in my KSP. You might want to post a list of mods you're using so others who have similar mods can try it.

Also, double check that they are all up to date. This thread may help with that.

http://forum.kerbalspaceprogram.com/threads/74457-ARM-Pack-0-23-5-Mod-Compatibility-Thread

Also, sorry if it seems like some of us aren't listening. Since you are new, some of your posts were delayed in showing up, which led to a bit of double asking for craft files and pictures.

[TheCardinal]

Right click on the engine of the fifth stage in the VAB. If the appearing menu contains "Shutdown engine" the engine has been activated in the VAB by you in a previous editing session. Click on the button next to "Shutdown engine". At the launch the engine won't work anymore until the fifth stage is activated.

Hope this helps.

[Pecan]

I can't really tell but from the name 'probe craft' and the engines you have it looks like you could have a huge amount of thrust at launch. Possibly enough to tear the whole thing in half and make stage 5 the active, lowest remaining one.

[Technical Ben]

Also double check under action groups. The number of times I've put a stray part under "Stage" in action groups.

[Red Iron Crown]

I can't really tell but from the name 'probe craft' and the engines you have it looks like you could have a huge amount of thrust at launch. Possibly enough to tear the whole thing in half and make stage 5 the active, lowest remaining one.

In my experience, unplanned disassembly does not activate stages, or even delete those that were just jettisoned. You would have to space through the lost stages to get to the appropriate engine.

[dandrestor]

Right click on the engine of the fifth stage in the VAB. If the appearing menu contains "Shutdown engine" the engine has been activated in the VAB by you in a previous editing session. Click on the button next to "Shutdown engine". At the launch the engine won't work anymore until the fifth stage is activated.

Hope this helps.

Alas, it's not this. I have no "Shutdown engine" option in the VAB. The option is there during flight, though.

[dandrestor]

I downloaded your craft and it appears you have several mods. I'm not running most of those so I can't check it in my KSP. You might want to post a list of mods you're using so others who have similar mods can try it.

Also, double check that they are all up to date. This thread may help with that.

http://forum.kerbalspaceprogram.com/threads/74457-ARM-Pack-0-23-5-Mod-Compatibility-Thread

As parts go, I'm using RealEngines, ProceduralFairings, ProceduralParts, AIES_Aerospace, MechJeb2, KWRocketry, RealChute, RealFuels. They're all the latest versions. I will check out the link you gave me and see if I find anything there.

Also, sorry if it seems like some of us aren't listening. Since you are new, some of your posts were delayed in showing up, which led to a bit of double asking for craft files and pictures.

Thanks. I think my first five comments needed to go through a moderation process, now I'm good to go however.

[TheCardinal]

Alas, it's not this. I have no "Shutdown engine" option in the VAB. The option is there during flight, though.

Is the option also visible when the craft is standing on the launchpad awaiting launch?

[Pecan]

In my experience, unplanned disassembly does not activate stages, or even delete those that were just jettisoned. You would have to space through the lost stages to get to the appropriate engine.

Hehe, is it also you experience that unplanned disassembly is predictable?

I was fishing for something that might be useful and I have had occassions when 'disassembly' was taken as a staging event. Not likely though, I know.

[FenrirWolf]

You can tell for sure if something broke upon loading or not by hitting F3

[Red Iron Crown]

Hehe, is it also you experience that unplanned disassembly is predictable?

I was fishing for something that might be useful and I have had occassions when 'disassembly' was taken as a staging event. Not likely though, I know.

Really? I've never had it happen in all the disassembly events I've experienced (and there have been many). Something new everyday, I guess.

[pxi]

As parts go, I'm using RealEngines, ProceduralFairings, ProceduralParts, AIES_Aerospace, MechJeb2, KWRocketry, RealChute, RealFuels. They're all the latest versions. I will check out the link you gave me and see if I find anything there.

IF you are using Mechjeb's ascent guidance, try turning off the autostage option. I've had that behave screwy a couple of times.

[Pecan]

...Something new everyday, I guess.

Must be. I don't get many disassembly events because I tend to Esc/F3 and revert before they go completely haywire but, yes, on a few occassions I've had higher stages that snapped off activate as if they'd been staged.

Edit - with pxi's comment in mind it's quite possible that the times I've seen disassembly => stage may well have been MJ-controlled. If that's so, it may have been MJ trying to recover what was left of the rocket by autostaging. (Bleh, I should have thought of that earlier. It makes the whole scenario less interesting :-( )

Edited April 27, 2014 by Pecan

[dandrestor]

Is the option also visible when the craft is standing on the launchpad awaiting launch?

On the launchpad, apart from the pitch-trim/gimbal/thrust controls, I have the options to Jettison, Toggle, and Activate Engine. If I press "Activate Engine", that changes to "Shutdown Engine" (having done this throttled down, though, there was no actual engine start-up).

[dandrestor]

Hehe, is it also you experience that unplanned disassembly is predictable?

I was fishing for something that might be useful and I have had occassions when 'disassembly' was taken as a staging event. Not likely though, I know.

On the launchpad, the event log is clean - no disassembly.

You can tell for sure if something broke upon loading or not by hitting F3

Thanks! This is most useful.

[dandrestor]

IF you are using Mechjeb's ascent guidance, try turning off the autostage option. I've had that behave screwy a couple of times.

This happens event when doing a manual lift-off.

[dandrestor]

A couple of you suggested it may be that the engine is in the "Staging" action group - it's not this, checked again.