Flight Question How do you translate your ship in Orbit?

[CommanderRich]

I was watching the awesome video by Tex "DGIV to ISS Video Tutorial Redux" and while attempting to line up the orbits of the DGIV and the ISS, it was mentioned, by Tex in the tutorial, that he had to translate the DGIV a bit to get the RInc exactly to "0.00". I understand everything up to the "translate" portion. What exactly does the term "translate" mean in this context and how do I go about performing this maneuver so that I can line up my DGIV RInc precisely to "0.00".

Thank you in advance and I hope I have been clear in my question.

Cheers!

 

[Artlav]

That means getting RCS into translation mode (/) and using their finer-than-main-engine thrust to carefully tune the trajectory.
Try pulsing each pair and looking which ones make Rinc reduce.

 

[CommanderRich]

Thank you for this explanation, however, I am still too new to this program to understand what you mean. Is it possible that you could link me to a .pdf which explains this, or if you could step me through it? Better yet, is this process explained in the DGIV manual?

Thank you again for the help.

 

[DaveS]

Thank you for this explanation, however, I am still too new to this program to understand what you mean. Is it possible that you could link me to a .pdf which explains this, or if you could step me through it? Better yet, is this process explained in the DGIV manual?

Thank you again for the help.

Try the Orbiter manual, Orbiter.pdf in the Doc subfolder.

 

[diogom]

Translation of the craft is firing its RCS engines but instead of giving a rotation to the craft, they move the craft to the side, front, backwards, up and down.
Reducing the Rinc to 0.00 on spacecraft with a higher thrust can be hard, so, when you're close to 0, you cut the main engines, and as Wishbone explained, you switch to Translation mode. You can then fire the RCS which will get you to 0.00 easier, since they have much less power.
Since you probably are in a Orbital Normal or Antinormal orientation, you should press Numpad + 6 to translate forward, or Numpad + 9 to translate backwards, until Rinc is 0.00. If not, try with other keys.

 

[PhantomCruiser]

If you have OrbiterSound installed you will hear a voice say "Translation" or "Rotation" every time you press the [/] key on the numpad. There is also an indicator in the generic cockpit view that will toggle back and forth as well.
In translation mode, the numpad keys [1] and [3] will 'translate' the craft left and right, [9] and [6] move you forward and backward, while [8] and [2] are up and down.

If you hold down the [CTRL] key while in translation mode, the thrust value is greatly reduced to 'fine tune' an approach to a station.

 

[diogom]

If you hold down the [CTRL] key while in translation mode, the thrust value is greatly reduced to 'fine tune' an approach to a station.

Really? I've learned something new today. Thanks.

 

[garyw]

Ctrl reduces the thrust of the RCS to just 10% I always use that for docking. It's much easier to control your approach.

 

[CommanderRich]

Thank you all for the tremendous help and invaluable information. This is a wonderfully helpful community and I certainly appreciate the effort. Thank you all again.

---------- Post added at 11:44 PM ---------- Previous post was at 11:43 PM ----------

OK, I tried the process explained above but to no success. I was able to lower my RInc to 0.03 in the initial phase, I time warped to my next slight burn and got it to 0.02. At this point I went to translation mode and there I got lost. I tried using the numpad keys, in translation mode, to try to get RInc to 0.00, however, no matter how long I spent on the 1, 2, 3, 8, whatever keys, the RInc value never wavered from 0.02. My problem is that once I get to the second burn, and lower the RInc to 0.02, I do not know what direction to go in translation mode. Or I am not doing something right, because as I mentioned, the value never changes no matter how long I burn or in whatever direction.
Thank you again for any help. I am getting so close, 0.02, however, I hate to continue because even that small amount off over a large enough distance can be a huge miss.

 

[diogom]

Rinc reducing burns are performed at either the Ascending Node or Descending Node. Depending on the two, you must use the Orbit Antinormal or Orbit Normal autopilots (just like prograde, retrograde). At the Ascending node (AN) use the Antinormal, at the Descending Node (DN), use Normal. In both, to reduce the Rinc you must translate forward, or backwards if going forward increases Rinc.

 

[CommanderRich]

I am approching an Ascending Node and I have set the craft to Antinormal for the burn. I get the RInc to 0.02 and there I lose control. Thank you again for the help, I will continue to try to get the number to 0.00.

 

[diogom]

Loose control how? The number keeps changing and getting to everything but 0.00?

 

[CommanderRich]

I finally got RInc to 0.00. I went back and made sure to wait until the ship was aligned with the AN and went right into translation and burned up or down, depending on how the RInc number responded and I finally got 0.00.

I think I will be practicing that for a long time, but I finally got it to work.

Thank you again for your patience and time. I hope someday I am knowledgeable enough to help others like you have helped me.

:tiphat:

 

[PhantomCruiser]

Relax a bit now dude. The next challange will be to sync with the station, then a rendevous/docking. It takes time and practice, practice, practice.

And while Orbiter can do the math for you, it still is rocket science after all. :thumbup:

 

[CommanderRich]

I can certainly see that now...and I have started the procedure over and over in order to learn the process by heart. I am also doing some reading to make sure I not only understand the terminology, but the reasons behind the processes I am doing in order to dock an earth based vehicle with an object already in orbit. Being a lover of science, I find the whole thing to be fascinating. I have started to sync with the station, and I am taking it slow. I assume that the sync process I am learning now to dock with the ISS will be pretty much the same no matter which craft I try to dock with? No matter where it is?

One last quick question. Is Orbiter limited in where it can operate? Everything I have seen so far relates to our Solar System. Does Orbiter give you the ability, if you wanted to try it, to go to, say, Alpha Centauri?

Thanks again and keep the comments coming...that is how I learn.

 

[Loru]

One last quick question. Is Orbiter limited in where it can operate? Everything I have seen so far relates to our Solar System. Does Orbiter give you the ability, if you wanted to try it, to go to, say, Alpha Centauri?

Thanks again and keep the comments coming...that is how I learn.

As for now you can freely travel only within our Solar System. There are few add-ons that provide multiple star systems but with them you make a "jump" to to another systems.

AFAIK depending on specific PC Orbiter losses accuracy somewhere around Neptune's orbit. This is way it's coded so for now there is no soulution to this problem.

Here is discussion for that topic.
http://orbiter-forum.com/showthread.php?t=21747

 

[PhantomCruiser]

There are some other solar systems available on the 'hangar for download. I haven't tried them, but from what I understand it's a custom solar system that replaces the 'default' with the new 'custom' system.

At the moment, the further you get out from the sun, Orbiter can begin to act a bit strange due to the math calculations involved with such large numbers. There is a thread here about craft/Ummu's hopping around on their own and docking troubles (etc, etc) it was mentioned as a bug IIRC.

(ninja'd by Loru :ninja

Regarding the sync with object, "Go Play In Space" is a big help, and if you don't already have it, you should get it. http://www.orbiter-forum.com/tutorials.php. Tex's video tutorial "DG4 to ISS" helped me out, even though I could already launch, align, sync and dock. A few things Tex'd mentioned helped me do the same using less fuel (I was a little heavy on the throttle before).

To read it in "Play in Space" is one thing, but to see it on the video really helps it to make sense.
Happy Orbiting!