Scenario Editor and more fuel efficient orbit sync...

[Hoggorm]

Hi,

1 - I would like to add the ISS to a scenario, but realize that when I use the Scenario Editor, the ISS is not placed in orbit as it is in real life, but at a general point in space above equator.

Is there an easy way to add the ISS (including all its orbital parameters from real life)? Or - where can I find this information if I have to enter them myself in the Scenario Editor?

2 - After launch, and when I am in orbit, I would like to sync my orbit so that I will be able to reach (and dock with) the ISS sometime in the next orbits. With the DG that is no problem, using the Sync Orbit MFD. The "problem" is that I would like to do the same with the Space Shuttle later, and then there will not be as much fuel available.

Using the DG I normally get a DTmin at about 0.00 around the middle of that list, but then I've used a lot of fuel. And I will also need a lot of fuel when I approach the ISS.

I have adjusted the List Length to what I believe is maximum (20 orbits). Is there a way to see even more orbits? When the space shuttle lifts up, the often require more than 20 orbits to reach the ISS (?).

How can I be more fuel efficient during orbit sync? I use the Launch MFD for orbit insertion.

Thanks,

 

[tblaxland]

1. Use the TLE scenario editor here: [ame="http://www.orbithangar.com/searchid.php?ID=2617"]Scenario Editor TLE[/ame]
and get TLEs from here: http://spaceflight.nasa.gov/realdata/elements/
or here: http://celestrak.com/http://celestrak.com/

2. The best way to be more fuel efficient is to wait longer. You can also try inserting into a lower initial orbit, since that will make you catch up faster. Alternatively, you can wait for a better launch window where the ISS is not so far ahead. Only 20 orbits (actually 19, IIRC) will fit on the Sync Orbit MFD screen. Yes, the Shuttle normally takes more than 20 orbits to reach the ISS. STS-124 arrived at the ISS on orbit 30. STS-125 arrived at the HST on orbit 31.

I also find Rendezvoud MFD very handy for planning rendezvous with low insertion delta-Vs: [ame="http://www.orbithangar.com/searchid.php?ID=1199"]Rendezvous MFD 050621[/ame]

 

[Hoggorm]

Thanks for a great answer tblaxland!

1 - I'll check out the TLE Scenario Editor. Hopefully it will be way easier if I can import TLE's from those two sources.

2 - I'll try the Rendezvous MFD. What I'm looking for is a way to know that in - let's say - 32 orbits I'll reach the ISS. Or that on orbit 32 I'll be pretty close. Maybe the closest I'll be in the next 100 orbits? How else can I know what orbit to aim for to use the least amount of fuel?

 

[tblaxland]

2 - I'll try the Rendezvous MFD. What I'm looking for is a way to know that in - let's say - 32 orbits I'll reach the ISS. Or that on orbit 32 I'll be pretty close. Maybe the closest I'll be in the next 100 orbits? How else can I know what orbit to aim for to use the least amount of fuel?

Rendezvous MFD can predict a fair way out, although the equations that it is based on will become less accurate the further into the future you look, especially the further your target's orbit is from circular. It is also less accurate when you have non-spherical gravity sources enabled.

EDIT: Another way you can easily waste fuel is by rotating too fast to get into position for a manoeuvre. Instead of using the autopilots, fly the steering manually to keep your rotation rates lower (say 1°/s - many autopilots will go at about 5°/s), at least until you are close to the target orientation then switch to auto-pilot.

 

[Hoggorm]

The TLE Scenario Editor worked perfect! Thanks!

 

[Hoggorm]

Regarding the TLE Scenario Editor:

Today I tried to change the date to 18 may and the clock to current UTC time. Then the ISS moved to cross the US on an easterly track. However the real ISS at the same time was over South Africa on an north easterly track.

When I've used the TLE information to update the position of ISS in Orbiter, should it not appear at it's correct place in space (orbit)?

If not, how can I fix it so that it does?

Thanks,