docking to ISS FINAL!!!( I hope)

[me]

okay i am tired of this so can someone just just give me a detailed explanation from take off to
docking? i am starting over!(i think i made a mistake early on) and I don't want to use the stupid
manual...it doesn't seem to help! so maybye a link to a good tutorial would help. PLEASE
HURRY

[canadave]

If I may make a suggestion/observation:

It seems to me that you're going about this the wrong way.  You don't understand the basic
concepts/terminology of spaceflight (I deduce this from your "attitude" question in the other
thread), and instead, you want a simple "press this button to get here, then aim at that HUD icon
to get near ISS, then press that button to go closer and dock" kind of answer.

The beauty of Orbiter is that it forces players to actually sit down and *learn concepts*.  I didn't
understand much about orbital mechanics at all when I first started using Orbiter.  But I wanted to
know how to get to ISS, so I sat down and read the manual.  Didn't help much.  Then I realized I
had to sit down and actually LEARN the concepts that were being TAUGHT in the manual, rather
than looking for the manual to tell me "Do this, this, and this, and you'll get to ISS."

A tutorial might tell you HOW to get to ISS, but unless you seriously sit down with the manual and
STUDY IT (yes, it might take you a week), you won't know WHY you got to ISS.  And without
knowing that, even if you make it to ISS, what's the point?

I highly suggest that you go back and read the manual...ALL of it.  If you don't understand the
concepts, READ IT AGAIN.  And again, and again, until you understand.  It took me about five or six
readings of it to start to understand what was going on.  Then the docking/flight processes
became a lot easier to master.

A final thought--spaceflight is about patience, if nothing else.  Impatience won't serve you very
well in your search for answers.

--Dave

[DanSteph]

It seem to me that you start from the wrong way,
start slowly doing some tutorial as the trevor john one
on mars, try to understand what you do than start
harder flight as reaching the iss from earth.

It took me some try and I think it even took me more days than
you to make my first docking at the ISS, but at this time
I knowed exactly what I was doing.

And you would be kind to not open more thread
on this topic , in case you didn't noticed one is enough
your new post will always bring the thread in the top
of the forum. and a thread can go far more than 500 posts
so you have enough room in one thread.

Thank you,

Dan

[canadave]

I might add that it will be hard to find a tutorial on approaching and docking with ISS that will be
*better* than the one in the Orbiter manual.  No matter what "tutorial" you choose, you still need
to study it carefully and understand the underlying concepts.

==Dave

[Krytom]

The way i found how to do the basics of orbits was in a science lesson. (They are useful after all.)
8o

Before that i was trying to fly to the moon by pointing the nose at it and burning as much fuel as
possible.

Also when i read how to use the Orbit MFD everything just came together. Now i can get to the
moon and back with the help of tutorials and the Transfer MFD.

But it does state on the Orbiter main site that 'the learning curve can be steep' so you have to,
before playing Orbiter take in mind that you are not going anywhere unless you read the manual
and a ton of tutorials. I have found that Harmsway's site has brilliant tutorials and that the DGII
manual has great DGII and DGIII specific stuff.

Enjoy your reading.

Krytom

P.S. Please no more useless threads.

[me]

hi guys! so i took your advice and started reading the manual it is all starting to make sense but i'd
like you to help me understand the whole sync orbit thing!

[Wilko]

Thats where I used to have difficulty to, but once you get your head wrapped around it its quite
easy.

Sync orbit allows you to either slow down or speed up your craft so on numerous orbits you
eventually catch up or step back to whatever you're sync'ing it with.

1: Press Shift-T to insert a target (ISS)
2: Repeatedly press Shift-M (I think) Select either 'Sh-Apoapsis' or 'Tg-Apoapsis'

I've found it necessary to first of all ignore what the numbers mean, but just know what to do with
them.

3: Point your ship Pro-Grade.
4: Engage ship thrusters

In the Sh-ToR column, the numbers should be going up at a faster rate than those in the Tg-ToR
column. If two numbers are coming close to matching, they will light up yellow to indicate which
are close.

5: Once they are the same number, shut off the engines.
6: Double check that your Apd (maximum altitude) is much larger than your Ped (minimum
altitude). Your Ped should still be above approx 160km.
7: Double check that you have done the burn correctly by noting that the DTmin number (on the
Sync MFD) is around zero. If you wish you can make small corrections to make this closer to zero.

As you near the target, the Dist number on the Sync MFD should be fluctuating, but overall getting
smaller each orbit.

8: When within 500-1000km of the target, change your HUD to Dock and set the frequencies of
the ISS (XPDR and one of the numerous docking frequencies (look them up using Ctrl-I)) using the
radio MFD (Shift-C).

9: The XPDR of the target should show up as a green box on the HUD along with the distance.
Watch the distance. When it stops and starts to get larger, point your ship at the crosshair (V ISS
or something) and fire main thrusters.

10: If the numbers are going UP instead of DOWN below that crosshair, shut off the engines and
point the nose at the crosshair with a circle around it and fire main engines again. The numbers
should rapidly count down. Once they are around zero, the relative motion between you and the
target should be hardly any.

11: Point your nose at the target and fire main thrusters. You should close in on it.

12: Repeat steps 9 to 11 if necessary.

Thats the Sync tutorial.

[canadave]

OK, now that you're asking questions about understanding the manual and not demanding
answers, I can help.

Here's an analogy that might help understand Sync Orbit:

Picture yourself in a race car going around a circular track at a certain speed.  Now imagine a
second race car that's halfway around the track from you at the same speed.  If you want to get
to that second race car, what can you do?

The answer is either speed up your own car to catch up, or slow down and let the second car
reach you.  This is basically what happens with the Sync Orbit function; you want to either slow
down or speed up your own craft, and after a certain number of orbits, your spacecraft will
intersect the target.

Dave

[Arkalius]

One thing to add though, is that unlike the racecar example, you don't slow down by "letting off
the gas" or speed up by accelerating... You slow down by going faster. This doesn't seem to make
sense but the reason why this is true is because if you increase your speed while in orbit, your
speed at the other side of the orbit will decrease. Not only that, but the amount of time it takes to
go around the planet once will increase. This will allow a target that is behind you to catch up. If
you wanted to catch up to a target in front of you, you would want to slow down (which would
cause your speed on the other side of the orbit to increase) because this would reduce the
amount of time it takes to complete one orbit, allowing you to catch up to the target.

Orbital mechanics is not a very intuitive subject for the unitiated. Have you ever heard someone
say "It's not rocket science!" in reference to something? Well, this is rocket science. It's supposed
to be hard. Why do you think astronauts usually have multiple doctorates?

[DanSteph]

Yes rocket science... Oh God it's so marvellous HURRY UP NASA AND OTHERS
WE WANT MARS, MOON, *SEING* OTHER STAR'S PLANET !!!! err... mmhhh sorry.

Also an explaination that take only fews words and some hand drawing
to illustrate become really more complicated when you can only write
a text without actually showing things.

In fact the basic of Orbit is somewhat "simple" but things goes really
worse with multiple G body and interplanetary trip.

(have you seen the Rosetta planned trip ?  10 years trip while using mars
and earth slingshot.. I would not be able to calculate even the first orbit
http://www.rmki.kfki.hu/kffo/missrose.html


Dan

[me]

okay i've read through the manual and understand more or less i tried the same "docking with
ISS" but i am having problems (i really do understand what i am doing but can't figure out what i
am doing wrong) i only have these "problems" from the sync orbit part after that. (other than that
i'm doing great (i think)). okay, one of the probs is this: when i turn prograde and boost my orbit
gets larger, if i turn retrograde and boost until on of the Sh-ToR is equal to one of the Tg-ToR my
orbit gets to small and i bounce off the atmosphere. baaa-hum-bug.

[Wilko]

Don't go retrograde... ever. I found that to be a real pain. Always be oriented pro-grade. When
you get in sight of the ISS, when you burn towards it and lower your relative velocity etc, your
orbit will get sent back to its original state. Never fire retrograde, it can cause all sorts of
problems.

Keep trying One day it will click.

[DocHoliday]

One reliable way to sync orbit is to set the interception point to your targets apoapsis and
increase your apoapsis with a prograde burn at the TARGET's periapsis (not your own!) and
increase it until they are at an exactly same altitude. I know this sounds complicated, I hope you
understand.

Now when you come around to the new apoapsis (NOTE: about 60seconds more or less before)
which should be the same as the target's, burn prograde and watch the Sh-ToR. Burn until it gets
to zero, or if you have enough fuel (like with the DG) burn until you only need one orbit to intercept
the target. Then just coast around the planet. When you reach your apoapsis (the one you
created just now), check your Sh-ToR. If it changed you can now adjust it with RCS linear bursts
and then wait again to drop back to periapsis and a little before that set your frequency and HUD
to Dock, point your ship into the crossed circle and burn until your reach zreo relative speed.

That should be the easiest way I came across, but not the most fuel efficient.

Good luck,

[me]

ahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh!!!!!!!!!!!!!!!! okay! i can't get this! can someone
explain not how to but what should happen when i fire prograde? and how close should sh_tor
and tg_tor be? someone help!!!!!!!!!!!!!!!!

[Pierre, LFPG]

Hi "me"!

If you want to know WHAT happens when you fire prograde... just try it and watch!

Pierre, LFPG, STV1010

[glObalist]

LOL man!

[canadave]

What exactly do you mean by "what should happen when I fire prograde"?  Normally, this
increases your apoapsis.  If you fire prograde long enough, you'll escape orbit.

Re your other question:
Orbiter manual, page 69.  It's all there.

Dave



Post Edited (03-04-04 21:50)

[Krytom]

When we talk to "Me" it sounds like we're talking to ourselves!

[DocHoliday]

Come on ME. (What's you name anyway?)

People are really bending over backwards for you here. Do gives us an accurate description of
where you are and what the problem is, how much manual did you read so far and what you want
to do. Coz, I'm kind of lost.

Cheers,

[harmsway]

OK you guys will think I'm nuts but when I first started learning how to use the sync MFD someone
in the official forum had this suggestion...

don't use the sys MFD use the Orbit MFD

I know it sounds silly but it really helped me out. Learn to sync to station with only the Orbit MFD.
Think of canadave's race car exapmle above. If you need to catch up lower your orbit or an even
safer way increase your orbit to let the station catch you. This will take quite a number of orbits
around earth. When you and the target are getting close ( the arc between the green and brown
lines ) begin to match orbital elements with small adjustment burns. Mainly your Ped and Apd
should be nearly the same only leave the T ( time to make complete orbit ) to your advantage.

After you have docked several times this way then you will be ready to take advantage of the sync
tool.

http://www.eharm.net/shop/freeware/orbiter/tutorials/orbiter_instrument/synchronize.html

[canadave]

That's actually a really good idea.  I usually do my Sync Orbit attempts with the Sync Orbit MFD on
my left, and the plain old Orbit MFD on my right.  It gives me two perspectives to work with as I
attempt it.

Dave

[Dave Grover]

Darn, Dave!  

I have the Orbit MFD on my left and the Sync Orbit MFD on my right!

Grover  



Post Edited (03-09-04 06:31)