SSU Development Thread (2.0 to 3.0)

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I've fixed the pushbutton issue (it's a bug in PushButton.cpp). Should I check the fix in to the trunk, or do you need in the MPS branch?
 
I've fixed the pushbutton issue (it's a bug in PushButton.cpp). Should I check the fix in to the trunk, or do you need in the MPS branch?

Great!!! To the mps branch if you could.
Many thanks! :thumbup:
 
I need coordinates for the both feedline vents.
Where are they? Well the LH2 is well visible on left side of the tail, aft of the APU exhausts. The LO2 is more tricky. I can't find a "flight image" where I can see it in the location where diagrams and literature place it. The only image (that I found) where something is visible is this of the birth of Atlantis
space-shuttle-atlantis-construction-aft-fuselage2.jpg

I think is the little dot (it's only 1 inch) in bottom half of the sidewall, below the row of 3 panels.

Also, just uploaded PanelC3, and the SEP switches need a little adjustment in the coordinates, as it looks like they're floating.
Many thanks!!! :cheers:
 
I'm currently on a very limited connection right now so I can't upload any photos, but based on my research, the LO2 relief port is located on a HRSI tile below the APU-2 service panel.

Here's the pos numbers:
Code:
2.92116, -3.44059, -10.8442
 
Yep, that's the middle of the 3 panels that I mentioned above, so looks like it's that "dot".
Those coordinates are of what vent, LH2 or LO2? (need both)

Don't worry about pictures, I just need the coordinates. :cheers:
 
Yep, that's the middle of the 3 panels that I mentioned above, so looks like it's that "dot".
Those coordinates are of what vent, LH2 or LO2? (need both)

Don't worry about pictures, I just need the coordinates. :cheers:
LO2, on the starboard sidewall of the aft compartment. The other two "panels" are the 9(FWD) and 8(aft) vents.

LH2 feedline relief pos:
Code:
-0.434188, 1.5138, -10.8137

Try this if you don't already have them: https://web.archive.org/web/20050720004209/http://spaceflight.nasa.gov/shuttle/reference/sodb/
 
LO2, on the starboard sidewall of the aft compartment. The other two "panels" are the 9(FWD) and 8(aft) vents.

LH2 feedline relief pos:
Code:
-0.434188, 1.5138, -10.8137
Try this if you don't already have them: https://web.archive.org/web/20050720004209/http://spaceflight.nasa.gov/shuttle/reference/sodb/

I have those for some years now, thanks anyway. And thanks again for the coordinates. :thumbup:
If you have time please correct the positions of the switches in panel C3.
 
I have those for some years now, thanks anyway. And thanks again for the coordinates. :thumbup:
If you have time please correct the positions of the switches in panel C3.
Could you describe the problems you're having with the C3 switches? Do they physically need to change in the actual VC or is it code?
 
I think the coordinates are not exactly correct, because the switches are kind of "floating" above the panel.... it's a similar issue to what we had in some switches in panel R2 sometime ago.
 
I think the coordinates are not exactly correct, because the switches are kind of "floating" above the panel.... it's a similar issue to what we had in some switches in panel R2 sometime ago.
So code then. Try these:

Code:
ET sep: -0.08218, 1.69955, 14.06513
SRB sep: 0.00608, 1.70746, 14.0791
 
Looks good, thanks!
 
Just was thinking about changing the way the ET and MPS interact (to be able to do ullage pressures and level sensors), and I might have found (another) cause for the excessive performance during ascent: in reality there is propellant both in the ET and in the MPS manifold, but I'm not sure if in our ET propellant mass we are including the ~5400lbs from the manifold.
Another possible thing is that some of the propellant that comes into the orbiter gets vaporized and sent back to the ET to keep ullage pressure up. That tiny amount of mass, over 8.5mins, could make a difference...
 
Just was thinking about changing the way the ET and MPS interact (to be able to do ullage pressures and level sensors), and I might have found (another) cause for the excessive performance during ascent: in reality there is propellant both in the ET and in the MPS manifold, but I'm not sure if in our ET propellant mass we are including the ~5400lbs from the manifold.
Another possible thing is that some of the propellant that comes into the orbiter gets vaporized and sent back to the ET to keep ullage pressure up. That tiny amount of mass, over 8.5mins, could make a difference...
This could explain things. I just completed an ascent of STS-61G with the max SSME throttle set to 104% instead of the planned 109%. I did hit the target MECO parameters but only with 18 tons of propellant left in the ET. I did add the MPS manifold propellant mass (5400 lbs).

Does anyone know if that is low enough to trigger the ECO sensors, either LH2 or LOX?
 
Well, the LOX ECO sensors are in the manifold, so I would say to trigger them the mass (LOX only) would be around 4600lbs or less. For a LH2 ECO trigger, the remaining mass would be more than 770lbs (LH2 only). So it looks like the 18tons would not trigger them.

My plan is to have one pair of propellant tanks in the ET (LOX and LH2), feeding another pair in the manifold, that would be always full as long as there's prop in the ET and feeding the engines. We could then simulate the re-press mass flow so the mass at MECO is more accurate, and manage the ullage pressures, as well as having the correct ET mass at sep (probably helpful for "early" ET sep for aborts), seps with disconnect failure, etc. It's a big surgery, so I'm still thinking about it, to make sure it works. If anybody has any ideas please don't be shy :cheers:
 
I would maybe just use a single propellant resource for both LOX and LH2 in the ET and a similar single one in the orbiter and keep track of the exact mass ratio in a variable. This way we can treat them as simple "variable masses", without putting too much interpretation into them... they could represent any mass of the MPS propellant system, including gaseous and other masses that flow inside them (eg, ET ullage gases)
 
That's smart, it would make it more simple. Thanks!
 
I switched branches to test the MPS implementation so far and everything works very nicely. Just one question though: is the MPS GH2 INERTING procedure implemented? If so, how do I access panel R4?
 
I switched branches to test the MPS implementation so far and everything works very nicely. Just one question though: is the MPS GH2 INERTING procedure implemented? If so, how do I access panel R4?

Currently only the MPS dump and both vacuum inerts are done, all auto (I remember to be missing one part somewhere, maybe that's what you're referring to).
That's probably going to be done (plus the reentry purge/press/whatever) after I do the "ET/MPS mods". But I also need panel R4, which currently doesn't exist, and even if existed the current "head position" doesn't allow proper viewing of it.
 
Currently only the MPS dump and both vacuum inerts are done, all auto (I remember to be missing one part somewhere, maybe that's what you're referring to).
That's probably going to be done (plus the reentry purge/press/whatever) after I do the "ET/MPS mods". But I also need panel R4, which currently doesn't exist, and even if existed the current "head position" doesn't allow proper viewing of it.
We do have panel R4 as well L4 on the CDR side. Here's a screenshot of R4:

Right_Panels_VC.jpg
 
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