Problems with docking

[hexed pumice]

Hello,
I am having problems with lesson 10, docking into the LM. As the tutorial says, I separate and then I roll 180 degrees using the pitch (W and S) to face the LM. Now I need to align the crosses, but I have two problems:

• The settings are in HOLD and RATE CMD, which means that after I stop pressing any movement key, the thrust stops and it eventually stops rotating. This is fine for big movements (as the 180 degrees rotation I just did) but for very small movements, any key pressing seems to move the CM a lot and it is very difficult to do fine tuning. Is there a setting that I can use in which a soft key press just moves a little bit and it stops moving? Even with MINIMUM IMPULSE any small pressing keeps moving the craft...
• The crosses are not aligned, so I use a set of rotational and translation moves, but I ALWAYS end up with the axis of the CM and LM unaligned no matter what I do. Which keys should press (or avoid to press) in order to keep my axis aligned with the LM? I guess that axis alignment is essential for docking, but I do not know how to align them in the first place.

Thnaks for your help.

[zenith crescent]

I think you Roll by using Q and E

You Pitch by W and S

and finally Yaw by A and D

[hexed pumice]

hi, yes, I know that, but I should

i use translation too or just rotation?

[zenith crescent]

of course you will use Translation too for Docking ..

remember that Rotational is for : Roll, Pitch and Yaw

and Translational is for translating: UP, Down, Left, Right, Forwards and Backwards

so for Docking goes like this:

1. Detach from the SIV-B rocket segment.

2. Translate a little forward for taking distance from SIV-B.

3. At the right distance (more than 20 feet) try to Pitch down so you face the Lunar Module Docking port.

4. You will also need to Roll so you match the COAS Cross with your T shaped Aim.

5. Then you align the CSM with the LM docking port by using Translational movements (UP, Down, Left, Right, ).

6. Once you are perfectly aligned, translate forwards not more than 2.0 feet per second.

[magic moss]

Also, in realism settings, is the "automatic prograde rotation" on? During the more advanced levels of the game i recommend turning it off

[hexed pumice]

The problem I have is with axis alignment; when I rotate and translate to match the crosses, the axis of the CM and LM do not align, so even if I match the crosses, the docking does not happen because the two axis form an angle.

And I do not know how to watch that; I see the clear misalignment thanks to the external view, but I do not know how to control it with the instruments.

[magic moss]

Ah I see, could you share a few screenshots?

[stiff brook]

yeah sure a few screenshots I am fairly certain you are not lined up in 3D

remember to null your rates after coming forward or else you'll start drifting away more

remember to line up the red and the white bars before you proceed past pre-contact

or else you have to do a little bit of finagling

The target should look pretty much like the image above before you go in for contact

[hexed pumice]

Ok, When I separate it starts fine:

Then turn 180 degrees just using the pitch:

Maybe not perfectly aligned, but not that bad. But then I check the window:

Well, that is my first question: why is my cross to the left of the LM's cross?? I have ONLY used the pitch, nothing else. And whn I finish moving, I make sure all the rates are nulled.

After a few seconds, my rates are still nulled:

But also the CM seems to be moving, as this happens:

How did this happen?? I did not touch any rotational controls and the rates were nulled.

Then, I try to dock and this time I use: 1) the roll as the tutorial says to match the orientation of the crosses and 2) the translation controls to match the centers of both crosses, and this happens:

I an even more angled than before! How come? I swear to God, I did not touch yaw nor pitch, only roll a little bit as the tutorial said, and a bit of translation (which should not change your axis alignment, right?)

I am puzzled; I have played a little of Orbiter, and I am used in docking to 1) Align both axis using just rotational, so the axis of both bodies are parallel, and 2) Using translation to merge both axis and point to the right direction. It is true that everything is a bit related, when in Orbiter I use translation, it DOES affect rotation a little bit, but not that much, and the computer tells me if I have lost alignment, so I can re-adjust rotation. I know the Delta Glider is a futuristic fictional craft with a lot of computing power, though.

So I must be doing something wrong here with the Apollo, or missing something.

[zenith crescent]

for aligning the Cross aiming with the T target you need to use the translational controllers ..

I remember that Academy tutorial mission was created by me ...

maybe I can upload a little tutorial video ..

[hexed pumice]

I do use the translational controllers to match the crosses

And I manage to do it, but as you see my axis is messed up

[zenith crescent]

are you having trouble by nulling rotations or nulling velocities (Left, Right, Up, Down)?

in the picture you poseted it seems that the CSM pitched too much more than required

Do you know how to null rotations by using the FDAI ball?

look for the little black arrows, they should align to end rotations

[magic moss]

Hey!
Excellent, thank you! In the recent patches since my Apollo 13 mission I have been working quite a lot on the SIVB (all this work might lead to some new recent bugs), and I am about to roll out another fix to the SIVB where missions that does not command it to a fixed inertial attitude hold orientation during T&DE (like my Apollo 13 mission does), it goes into Orb Rate (like you see above), while your craft maintains a fixed attitude. This causes the SIVB to rotate compared to you. There is also a setting that "simplifies things" where on the Main Menu -> Realism Settings -> Prograde Rotation (bottom) that can cause some relative rotation.

But you do it correctly as you separate from SIVB, translate a but forward, and then pitch 180 degrees like in your screenshot. Once you are facing the SIVB you need to roll slightly to align the docking target with your COAS as @stiff brook posted above. Once you have this alignment you can close in. If the orb rate is on you will need to translate and slightly tune your attitude as you close in with the target.

In a few minutes I will roll out an update to this that might correct it.

[uneven snow]

Gave +1 flight-hours to @hexed pumice (current: #152 - 1)

[magic moss]

I could share my screen with you and show you how I do it, it will not take much time.

[hexed pumice]

Thanks, that would be great

[magic moss]

Ok, let me know when you want me to start the stream (I got time now at least)

[hexed pumice]

I can now

[magic moss]

Ok, let me get set up here

Ok, I am in the general voice chat

[hexed pumice]

Many thanks Petri! I have to leave now but I shall test and report back.

[stiff brook]

Did you null your rates before performing pitch over

[stiff brook]

you’re not lining up in all the dimensions and miss reading the docking target. And keep in mind in reentry the SIVB doesn’t station keep.

[stiff brook]

Also see the docking target where you have some of the red lights covered by the white lights and the white lights aren’t completely aligned with the red that’s showing you an additional reference to lineup with which it seems like you’re neglecting causing that

[hexed pumice]

Managed to do it; much better now thanks