SSU Development thread (4.0 to 5.0) [DEVELOPMENT HALTED DUE TIME REQUIREMENTS!]

[DaveS]

I've done some more research into our a first stage performance problems I and through alot of trial&error this is what I have discovered. This is a direct quote from my latest entry in ticket#20:

"I think I have nailed down the issues to differences in Low Q vs High Q (Performance Enhancement) pitch tables (High Q is slightly more aggressive), Adaptive Guidance Throttling (AGT) being off (it throttles down and causes multi-step throttle downs when it shouldn't) and finally us not having the historical throttle bucket numbers for the missions as well as the historical payload masses.
Points 1 and 3 have been identified by me through several 1st stage ascent runs of STS-107 using historical throttle bucket figures and payload masses."

So it is a four-factor problem:
1: Pitch tables not being the same for Low Q ascents and High Q ascents (Addressed by me in r.3285)
2: AGT most likely targeting a Low Q number which causes multi-step throttle downs
3: Our scenarios not having the historical payloads with their correct masses (STS-107 addressed by me in r.3285)
4: Our mission files not having the historical throttle bucket numbers, causing either late or early throttle commands easing the loads (STS-107 addressed by me in r.3285)

 

[DaveS]

Another thing for consideration is a switch from OrbiterSound to XRSound. This mainly due to that the development of OS rests on a single individual and is closed source while XRSound recently went open source. GLS did note a problem with SSU/SSV and OS 5.0: https://www.orbiter-forum.com/threa...rsound-5-0-for-orbiter-2016.38115/post-565903

 

[n72.75]

Yeah, unless you're planning a release for 2016/R90/OS5, pausing development makes perfect sense.

 

[DaveS]

Something I have been working on in case SSU comes back. Everything is now very accurate thanks to the Smithsonian National Air&Space Museum, as I have been using their freely available 3D model of the real Discovery created by laser-scanning the orbiter as she was parked on the Udvar-Hazy Museum floor. This only of the exterior of the orbiter, so nothing of the payload bay or other interior compartments unfortunately.