General Question I need some help here!!!

[lektunde]

Hello there. I just joined the forum a few weeks ago, and I need some help. I have actually been using orbiter for over two years now, and I have mastered quite a lot. I have launched the DG, and Shuttle to space, and even docked both with the ISS (through crude means, and several trials). But I have difficulties with the following issues.

1. I am a bit confused about launch inclination, and azimuth. What's the difference between these two? How do I know the exact inclination to launch to? And what figures do I need to look at in order to launch into my target inclination? When do I need to take off?

2. I need more explanations about the OMS 1 and oMS 2 burns of the shuttle. After the GPC MFD gets the shuttle into space, (i.e after ascent traj 2), I see a count down time clock on the GPC MFD a time display below the elapsed mission time. this clock has about 2 mins of time left, and the heading on this display says something like ('OMS MNVR EXEC'). So I just wait for the 2 mins to run out, but no burn occurs. Was I to do something within the two mins?

3. I downloaded and Installed the Guidance and Control MFD for STS. Whenever I get into orbit with the shuttle, and activate the rendevous command, it works. But after TI, CCB1, CCB2, CCB3, and Rendevous burns, it does a 'Station hold'. This hold goes on for a very long time without the shuttle ever getting closer for approached docking. If I try to accelerate time, enourmous amounts of ruel would be consumed by the RCS to stabilize the craft, and eventually, I would have to restart the simulation. What should I do? Or how long am I to wait for station hold? If there are additional information I've missed on this issue, I would like to know.

4. After I docked the shuttle with the ISS on one occasion (STS 114 scenario in shuttle fleet V4.2.0), I brought out the RMS, and pulled a cargo out of the cargo bay. But I did not know where, and how I was to attach the cargo to the ISS. How do I do this?

5. I need help with de-orbit and landing. I want to know how to do it very well.

I would like if anyone can help me as soon as possible!!!


Thanks.

 

[Urwumpe]

1. I am a bit confused about launch inclination, and azimuth. What's the difference between these two? How do I know the exact inclination to launch to? And what figures do I need to look at in order to launch into my target inclination? When do I need to take off?

Azimuth is the direction you fly to relative to the true north, while inclination is the angle between your orbit plane and a reference plane, eg the equator of Earth. If you launch at an azimuth of 90°, your equatorial orbit inclination will be equal to the latitude of the launch site.

Best way for you would be using launch MFD, otherwise, the math might be a bit harder.

2. I need more explanations about the OMS 1 and oMS 2 burns of the shuttle. After the GPC MFD gets the shuttle into space, (i.e after ascent traj 2), I see a count down time clock on the GPC MFD a time display below the elapsed mission time. this clock has about 2 mins of time left, and the heading on this display says something like ('OMS MNVR EXEC'). So I just wait for the 2 mins to run out, but no burn occurs. Was I to do something within the two mins?

No idea, haven't used GPC MFD for a while. But I remember that it doesn't launch the Shuttle itself, it only triggers the autopilot inside the Shuttle. OMS1 and OMS2 have to be triggered independently.

3. I downloaded and Installed the Guidance and Control MFD for STS. Whenever I get into orbit with the shuttle, and activate the rendevous command, it works. But after TI, CCB1, CCB2, CCB3, and Rendevous burns, it does a 'Station hold'. This hold goes on for a very long time without the shuttle ever getting closer for approached docking. If I try to accelerate time, enourmous amounts of ruel would be consumed by the RCS to stabilize the craft, and eventually, I would have to restart the simulation. What should I do? Or how long am I to wait for station hold? If there are additional information I've missed on this issue, I would like to know.

Just leave the station hold and dock. That you don't get closer and use a lot of fuel there is normal for a station hold.

4. After I docked the shuttle with the ISS on one occasion (STS 114 scenario in shuttle fleet V4.2.0), I brought out the RMS, and pulled a cargo out of the cargo bay. But I did not know where, and how I was to attach the cargo to the ISS. How do I do this?

Move it to a free CBM and release it.

5. I need help with de-orbit and landing. I want to know how to do it very well.

Start here: http://www.orbiterwiki.org/wiki/Intuitive_Atmospheric_Entry

 

[ar81]

1.Inclination refers to the inclination plane of the orbit respect to equator.
Azimuth refers to launch heading. For an orbit with a certain inclination, in different latitudes you would have different launch headings. For example, for an orbit that is inclined 30 degrees, if you launch from latitude 30, your launch azimuth would be 90 (east) but if you launch from equator it should be 60 (30 degrees from east).

2.OMS-1 is used only for OMS-1 required ascent profile, and it is used to raise apoapsis with your OMS engines. OMS-2 is used to circularize orbit as far as I understand.

5.[ame="http://www.orbithangar.com/searchid.php?ID=3988"]This tutorial [/ame]may be useful.

 

[lektunde]

Thanks for the reply

Thanks for the reply. I'll try controlling the shuttle for docking with the ISS, during station hold.
If I have any other difficulties, I'll let you know.:thumbup:

 

[Tommy]

In regards to launch headings, there is a formula that will calculate the correct heading. I'm not at home, so don't have it handy. If you download DanSteph's DGIV it's manual contains two versions of the launch heading formula. One is simplified, and not very accurate on a planet with any kind of rotational speed, the other is better, and more than accurate enough.

As for when to launch, for a trip to LEO and rendevous (like a trip to the ISS) launch about 300 seconds before the node, as displayed in AlignPlanesMFD.