Space Shuttle Ultra 1.25 Revision B development

[Urwumpe]

All we really need the KU for, is rendezvous and docking.

Yes, and for satellite deployment.


This one here:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810011799_1981011799.pdf

Is really great, I just skimmed over it, it contains a lot of information about the self-test sequence that I was still missing.

---------- Post added at 09:31 PM ---------- Previous post was at 08:56 PM ----------

And I just saw, it also contains the schematics for the discrete line connections to the real electronics boxes, in this case, we finally wouldn't need to guess...

 

[DaveS]

Any updates on the project? Been pretty quiet the last couple of weeks on the development front.

 

[SiameseCat]

I've been working on the entry guidance code, and I think I have a working drag profile for entry (one of the documents posted earlier has a complete description of the entry target drag calculation, and I've used that). I'm hoping to check it in in a few days, once I work out some controllability issues (at about Mach 4, the shuttle roll rate is ~1 deg/s, which is too slow).

Next step will be to figure out how to have the autopilot fly the entry.

 

[DaveS]

I've been working on the entry guidance code, and I think I have a working drag profile for entry (one of the documents posted earlier has a complete description of the entry target drag calculation, and I've used that). I'm hoping to check it in in a few days, once I work out some controllability issues (at about Mach 4, the shuttle roll rate is ~1 deg/s, which is too slow).

Next step will be to figure out how to have the autopilot fly the entry.

How is this going?

 

[SiameseCat]

I'm hoping to check the code in today or tomorrow. The drag profile seems to work very well throughout entry.

I haven't added the autopilot code yet; currently, the target altitude is displayed in the debug string and the entry has to be flown manually.

 

[DaveS]

Nice document overviewing the ET propellant loading at the pad: Computational Model of the Chilldown and Propellant Loading of the Space Shuttle External Tank

---------- Post added 02-21-12 at 12:19 AM ---------- Previous post was 02-20-12 at 11:54 PM ----------

Another nice document detailing the T0 umbilicals(both TSM carrier plates and OV flight umbilical plates): Shuttle Ground Support Equipment (GSE) T-0 Umbilical to Space Shuttle Program (SSP) Flight Elements Consultation

Has some nice photos from inside the aft compartment of the umbilical plates of the orbiter.

 

[Urwumpe]

You don't seem to know any PDF with something like inventory listings of the VAB? Most tools should be delivered by subcontractors for their work, but there must also be some lots of fixed infrastructure that should be documented somewhere.

 

[DaveS]

You don't seem to know any PDF with something like inventory listings of the VAB? Most tools should be delivered by subcontractors for their work, but there must also be some lots of fixed infrastructure that should be documented somewhere.

What kind of fixed infrastructure are you thinking of specifically? Stuff are moved around as necessary to clear the required space in the Low Bay and Transfer Aisle.

 

[Urwumpe]

What kind of fixed infrastructure are you thinking of specifically? Stuff are moved around as necessary to clear the required space in the Low Bay and Transfer Aisle.

What kind of stuff is available for utilization of the VAB. There must be some sort of document about this, I doubt they just decide to use the VAB for SLS without looking at the question what can still be used.

 

[DaveS]

What kind of stuff is available for utilization of the VAB. There must be some sort of document about this, I doubt they just decide to use the VAB for SLS without looking at the question what can still be used.

Well, based on my research, the only things usable for SLS is the RSRM segment fixtures and maybe the ET sling set. The orbiter sling set was custom designed built for the orbiter, so no further use for it.

The high bay platforms will be replaced with new ones. The cranes will stay the same, no need to replace those.

 

[SiameseCat]

I'm hoping to check the code in today or tomorrow. The drag profile seems to work very well throughout entry.

I haven't added the autopilot code yet; currently, the target altitude is displayed in the debug string and the entry has to be flown manually.

Code has been checked in now.

 

[DaveS]

Which file has the preloaded settings for the Orbit DAP? I'm thinking of fixing this problem: http://www.orbiter-forum.com/showthread.php?p=303204&postcount=1761

 

[SiameseCat]

Which file has the preloaded settings for the Orbit DAP? I'm thinking of fixing this problem: http://www.orbiter-forum.com/showthread.php?p=303204&postcount=1761

Are you sure it's still there? I fixed the DAP settings a while ago.

The code is in dps/OrbitDAP.cpp, if you want to change the settings (the DAP settings are initialized at line 79).

---------- Post added at 05:48 PM ---------- Previous post was at 05:47 PM ----------

I've been working on the entry guidance code, and I think I have a working drag profile for entry (one of the documents posted earlier has a complete description of the entry target drag calculation, and I've used that). I'm hoping to check it in in a few days, once I work out some controllability issues (at about Mach 4, the shuttle roll rate is ~1 deg/s, which is too slow).

Next step will be to figure out how to have the autopilot fly the entry.

Has anyone had a chance to try this out yet? I checked the code in a few days ago.

 

[DaveS]

Are you sure it's still there? I fixed the DAP settings a while ago.

The code is in dps/OrbitDAP.cpp, if you want to change the settings (the DAP settings are initialized at line 79).

---------- Post added at 05:48 PM ---------- Previous post was at 05:47 PM ----------


Has anyone had a chance to try this out yet? I checked the code in a few days ago.

I'll check the Orbit DAP. I guess I haven't noticed the changes. One problem with testing the new entry guidance is the the rolls. They're based on DelAz, not energy. So, once MM304 has been loaded, you don't have any information on how you're doing. It's just blank.

 

[SiameseCat]

I've been using the Shuttle Fleet's GPCMFD during entry, and switching to CRT MFD for TAEM. I agree that we need to add the MM304 displays to SSU, but GPCMFD does a good enough that I don't think this should be a priority.

 

[DaveS]

Just to let you know that I'm not really suited to manual entries as I fail them all. I just can't keep the drag under control. I can't even balance the altitude error, it just gets away from me.

One observation though, the first part of a fully AUTO entry was rock solid. It seems like the problem is always with the first roll reversal. It seems to get confused right when the roll is to be commanded.

 

[Poscik]

I'v been flying reentries for 2 hours now, and indeed, drag works very fine, TAEM and 80kft, 2.5mach and 60nm to landing site. But I'm experiencing one problem. At TAEM I'm commanding final bank to "intercept" heading to HAC. But even with 0% speedbrake, I have very low speed. At 30kft I should start the HAC, breaking 1 mach then. But after TAEM speed drops very fast, and I'm breaking mach 1 very soon after TAEM. Any tips?

 

[Donamy]

drop the nose more !!

 

[Poscik]

I had pitch between -5 and 0. This doesn't work so good, as I am too low (in spite of low speed). But TAEM is fully ok.

 

[David413]

I've been using the Shuttle Fleet's GPCMFD during entry, and switching to CRT MFD for TAEM. I agree that we need to add the MM304 displays to SSU, but GPCMFD does a good enough that I don't think this should be a priority.

Glad that this is working for you. You guys are the only shuttle sim in town now for Orbiter; I have officially retired the Shuttle fleet.

Best wishes...

Dave

---------- Post added at 17:56 ---------- Previous post was at 17:54 ----------

I'v been flying reentries for 2 hours now, and indeed, drag works very fine, TAEM and 80kft, 2.5mach and 60nm to landing site. But I'm experiencing one problem. At TAEM I'm commanding final bank to "intercept" heading to HAC. But even with 0% speedbrake, I have very low speed. At 30kft I should start the HAC, breaking 1 mach then. But after TAEM speed drops very fast, and I'm breaking mach 1 very soon after TAEM. Any tips?

In most cases during an actual entry of the shuttle, the vehicle dropped below mach 1 30 to 60 seconds before HAC intercept.

Dave