Flight Question Approaching ISS

[Nigge]

Hi! I am having some troubles approaching ISS with STS-88...
When I have entered the frequency I get two boxes, one D[ISS] and one V[ISS] what I understand I am supposed to track the V[ISS] using ROT thrusters and the LIN to move [V[ISS] towards D[ISS] but I cant seem to see the connection between what thrusters i apply...
If i press the 6 button on my numpad the V[ISS] seems to start moving, but then after a while it stops moving again, and i start to get further and further away from ISS... and to apply the 9 button on my numpad doesnt seem to help...

Can anyone just point me in the right direction... I understand that it needs a lot of practice but i cant seem to even get in the right direction

/Niklas

 

[Ripley]

Make sure your RInc (Align Planes MFD) and your DTmin (Sync MFD) are exactly at zero, and that your Rendez-vous point's height is exactly the same as ISS's (Orbit MFD).

If everything is like above, get very close to ISS without engaging engines. Relative speed should be low enough when you are, say, at 5 km or so. Get closer. When you are < 1 km you can start slowing down your ship by pointing V[ISS] and applying retrothrust (or by pointing -V[ISS] and applying forward thrust).
Then, with still some positive closure velocity (about 1 m/s), with LIN RCS, move V[ISS] indicator towards the docking corridor, and fine tune from there.

"T" to fast forward, "R" to slow down.
Lots of LIN/ROT pushes in the final alignment.

 

[Nigge]

Ok.
to begin with, thanks for your answer!

my values are right now:
My RInc is at 0.03 degrees
and my DTmin is at 9.12.

Is there any way to correct these down to zero or do I have to start all over again?
/Niklas

---------- Post added at 07:57 PM ---------- Previous post was at 05:23 PM ----------

Okey, now I have tried my mission once again and got a lot closer now.
But at about 1 km distance i tried to start slowing down.
By aiming at V[ISS] and applying thrust forward(LIN) so that the flames comes out the front... this did send me of course... and i never got any closer...

Any tips? Sorry, I feel like a n00b;-)

 

[Ripley]

Depends on how many orbits are left before Rendez-vous. Between you and the ISS there's less than 1.000 km now.

If you have more than 1 orbit left, when you are on your Rendez-vous point, orient Prograde and burn (forward if ISS is behind you OR backwards if it is ahead) with RCS LIN, to bring DTmin down.

Then bring up Align planes MFD. If you are lucky to happen on any node, orient Normal+ (DN) or Normal- (AN) and burn very briefly.

When you are one half orbit from Rendez-vous, it's your last chance to tune Rendez-vous height.

That's it.

 

[Nigge]

Im sorry but your answer was a bit over my knowledge-level... didnt understand what you meant...
Is it possible to simplify a bit? How do I see how many orbits I have left?
And how do I know that i am on my rendevouz point?

And what do you mean with: Orient Prograde and burn (forward if ISS is behind you OR backwards if it is ahead) with RCS LIN, to bring DTmin down

Isnt a prograde burn always in the same direction? how can it be backwards?

And how do i perform RCS LIN? and what happens if DTmin comes down?
It would be great if you could explain

Thanks
/Niklas

 

[Ripley]

Wow!!
It looks like you started with a step longer than your leg...

Read this
[ame="http://www.orbithangar.com/searchid.php?ID=3074"]Tutorial: DG to ISS[/ame]

Watch this
http://www.orbiter-forum.com/showthread.php?t=2055

 

[Nigge]

Possibly but still... my question remains...

 

[clive bradbury]

Based on Soyuz to Mir, but the RV principles are the same:

[ame="http://www.orbithangar.com/searchid.php?ID=5472"]Soyuz to MIR Tutorial[/ame]

 

[Nigge]

Thanks Clive! Ill look into that tutorial! Thanks for the tip!