- Oct 26, 2011
- Reaction score
Even if the Earth is "where it is supposed to be", the ISS SV conversion could be wrong.
Yeah, certainly can. In the case of the STS-126 launch scenario it could be other things as well. The ISS state vector was changed when the launch scenario was moved from T-11 hours to L-10 minutes, in this revision: https://sourceforge.net/p/shuttleultra/code/1546/ If, for example, the new ISS state vector was generated by coasting for that half of a day and nonspherical gravity was disabled during this procedure, then the error in the longitude of the ascending node would exactly fit with what we get after insertion. Maybe DaveS knows what he did there 5+ years ago. :lol: I haven't tried yet to load an accurate TLE for the ISS, but I have a feeling most of the LAN error would go away.
I have decided how I want to solve the saving/loading issue. The MFD will have saving and loading buttons in the settings menu. There you can save or load e.g. a "STS-126.txt" file in a MFD specific folder, probably in Config/MFD/ShuttleFDOMFD. There launch time etc. will be saved and in the future also the TIG-less rendezvous plan to load up for planning before OMS-2. And of course during a mission you will be able save rendezvous plans in any file you want. But I could also include the flown rendezvous plans for a bunch of missions with the MFD directly. The only downside of not using the normal MFD saving/loading will be that no parameters are saved in a scenario. So step 1 after loading a scenario where you want to use the MFD will always be to load the right mission file. Not too inconvenient I think.
---------- Post added at 19:31 ---------- Previous post was at 19:24 ----------
One way to check this would be comparing Earths axis and rotation with the global coordinate system at different times.
NASSP uses a slightly modified Earth config to compensate for, what I think is, mostly Earth rotation speed not being constant.
And I would be even more surprised if the star positions are correct over 50 years. :lol:
They are not. At least not the ones with large proper motion. The AGC has hardcoded star tables and you can see a small difference for some stars in Orbiter vs. where the AGC thinks they should be. This is solved by using star markers, which shows where you should be make your sextant marks instead of on the star in the Orbiter sky. But the difference is not significant enough to cause any bigger trouble, you could probably get away with now using the markers.