RCS tank priority

[E. F. Kranz]

Shouldn\'t the flight system give priority to RCS tanks on lower stages? That doesn\'t seem to be the case, currently.

Can anyone explain to me in what order RCS tanks are drained?

[sjwt]

Tanks are drained in lower stages first, but all of the RCS units always fire.

[E. F. Kranz]

Not on my ships, they don\'t.

[Leeksoup]

Not on my ships, they don\'t.

That\'s true. I\'ve thought for some time that it would be nice to be able to manually assign priority to RCS tanks, instead of just relying on the VAB to do it for us- I can\'t tell you how many times my rockets have drained my 'lander' stage of RCS while still in Orbital Insertion phase, just to leave the OI stage full of RCS fuel when I ditch it.

[Zephram Kerman]

In the VAB, if you mouse over a part, the corresponding stage icon lights up. So it should be possible to separate the RCS tanks and set the order manually. I haven\'t tested this though.

[sjwt]

In the VAB, if you mouse over a part, the corresponding stage icon lights up. So it should be possible to separate the RCS tanks and set the order manually. I haven\'t tested this though.

I do it all the time when its wrong, It always drains them from the tank that is listed as being in the highest numbers stage

[E. F. Kranz]

In the VAB, if you mouse over a part, the corresponding stage icon lights up. So it should be possible to separate the RCS tanks and set the order manually. I haven\'t tested this though.

Okay, explain this again to me, please?

I currently have a four-stage design... one heavy lift, one orbital, one lander, and one rover. I have RCS tanks on the three upper stages. In the VAB, they are all inside the correct stages. Explain to me then why the first tanks to drain are on the rover?

EDIT:

For grins, I switched the location (not physical, but in the stages) of the lowest RCS tanks from the orbital stage to the lift stage. Still draining from the top down.

[E. F. Kranz]

Forgive the crude illustration, but it\'s the best I can do right now.

What am I doing wrong?

Aw heck, I\'m lying to yall, sorry. The lower arrow is pointing to the wrong stage, since all the stages won\'t fit in a single window. Still, the point stands. It\'s draining my rover stage, not the two beneath it.

[DayOne]

Could this be fixed with fuel pipes? I know RCS tanks don\'t need them but it may cause the game to prioritise certain RCS tanks.

[sjwt]

Could this be fixed with fuel pipes? I know RCS tanks don\'t need them but it may cause the game to prioritise certain RCS tanks.

No, the fuel liens only effect LFT, just use the VAB and move them around in the priority list.

[MrMoog]

I\'ve had this exact same bug multiple times. And no, it\'s not RCS tank placed in bad order.

A workaround I found is, in the VAB, to remove the tank being used first, and replace them. It seems to correct the order. But yeah, it\'s kinda annoying.

[E. F. Kranz]

A workaround I found is, in the VAB, to remove the tank being used first, and replace them. It seems to correct the order.

Thanks. I removed every single RCS tank on the entire craft, and replaced them. That seems to have solved the issue. What a pain in the neck though.

[sjwt]

Thanks. I removed every single RCS tank on the entire craft, and replaced them. That seems to have solved the issue. What a pain in the neck though.

The easy way is to move the mouse over the part, then look at what it is highlighting on the list down the side(it helps to move your mouse over the part, then over a different type of part and then back again) this will show you where that tank is located on the virtual list, then you just move it in the list to where you want.

[E. F. Kranz]

The easy way is to move the mouse over the part, then look at what it is highlighting on the list down the side(it helps to move your mouse over the part, then over a different type of part and then back again) this will show you where that tank is located on the virtual list, then you just move it in the list to where you want.

Yeah, believe me, I get that. They were all located in the stage list exactly where they should be. They simply weren\'\'t draining properly.

While we\'re having the discussion (and yes, it seems this probably should be in the bugs forum (and may already be, for all I know, I haven\'t looked)) - I should describe how I arrived at this point.

The rover (absolute top stage) needed a redesign, but my lower stages were all pretty much perfect. So I disconnected all the lower stages, and rebuilt the rover.

I suspect this is what introduced the problem. I even did this, in order to do some ground testing:

Connected the lower 'lift,' 'orbital,' and 'lander' stages to the rover, and saved the craft. Then disconnected all the lower stages and 'launched,' to test drive/fly just the rover. (when you launch while objects are not connected to the craft, those objects disappear)

Then I went back to the VAB and loaded the saved craft, which of course had the entire ship connected underneath the rover.

I\'m sure that one of these interactions causes the thing to garble the RCS priority.

[E. F. Kranz]

I will suggest as a possible future feature -

A workspace where landers and/or rovers can be constructed and tested in their own environment, independent of whatever will eventually be attached beneath them.

For that matter, each stage might as well be constructed in its own, user-defined environment.

For instance: Currently, there is no way to test an orbital stage without first designing a sufficient suborbital stage.

And so on. There is no way to test a rover design in the environment in which it is expected to operate without first delivering it to that environment.

Surely any advanced space program would solve these rather simple problems.

[MrMoog]

The easy way is to move the mouse over the part, then look at what it is highlighting on the list down the side(it helps to move your mouse over the part, then over a different type of part and then back again) this will show you where that tank is located on the virtual list, then you just move it in the list to where you want.

The problem is that even if all the tanks are in the good place, sometimes small tanks from upper level (both in the ship and in the staging icons) fire before lower, bigger ones.

It seems to happens when you load a big saved craft in the VAB, remove the launcher part (with RCS tanks) while keeping the orbiter (also with RCS tanks), and rebuild the launcher (with new RCS tanks). The unchanged RCS tanks from the orbiter then fire first. Maybe something in the handling of saved parts.

Hard to reproduce on purpose with stock parts, but pretty annoying when you discover in orbit that your lander\'s tiny RCS tanks have been drained in a few seconds by the second stage without you knowing because they were way high in the staging icons.

You could try replacing only the tanks firing first, it might be enough.

Version 0.15 will probably solve this issue though. It\'s not gamebreaking, just annoying.

EDIT: Just saw your post:

So I disconnected all the lower stages, and rebuilt the rover.

I suspect this is what introduced the problem.

I think we\'re closing in

[Crowley]

I just tested this on my own rocket (I noticed the same RCS usage as you described) and I removed ALL RCS tanks & replaced them (and of course made sure they were in the right stage). It used the RCS\'s from bottom up to the top (as it should, per stage) as E. F. Kranz has done, so I can confirm it. I will be testing it again shortly....

*edit* Confirmed again.. uses bottom RCS stages, then the uppers.