SSU Questions thread

[GLS]

SVN updates are how you retrieve the latest check ins to the repository. And as GLS wrote, dual vessels in scenarios are unlikely to be supported due to the complexities of each vessel.

Currently. Hopefully that will change.

---------- Post added at 06:13 PM ---------- Previous post was at 06:09 PM ----------

Thanks: What I meant is if I regularly update SSU via SVN will the default and "standard" (one shuttle only) scenarios work?

The "default" SSU scenarios are updated with the code. "Private" user scenarios need of course to be manually updated when something related to the scenario structure is changed, but that shouldn't be hard to do (only boring :lol, one just needs to check how things are in the default scenarios.

 

[DaveS]

Currently. Hopefully that will change.

I don't see that as an option really when we get the real DPS in. Remember, we're only running one GPC right now and it is taxing enough on lower end PCs. Tacking on 4 more will make that even worse. Then you'll have 5 more in dual vessel scenarios adding even more calculations onto an already strained CPU.

 

[GLS]

I don't see that as an option really when we get the real DPS in. Remember, we're only running one GPC right now and it is taxing enough on lower end PCs. Tacking on 4 more will make that even worse. Then you'll have 5 more in dual vessel scenarios adding even more calculations onto an already strained CPU.

I don't have hard data to prove this, but I think the graphics are by far the limiting factor in performance right now. Even during loading, e.g. SSU vs DG, there's a huge difference as SSU has to load many more meshes and textures. I'm not complaining, it's just the way it is. :shrug:

 

[DaveS]

I don't have hard data to prove this, but I think the graphics are by far the limiting factor in performance right now. Even during loading, e.g. SSU vs DG, there's a huge difference as SSU has to load many more meshes and textures. I'm not complaining, it's just the way it is. :shrug:

That's not a problem for modern GPUs, they can handle alot more than we're throwing at them.

 

[Capt_hensley]

How hard would it be to assign 1 GPC per core on multi-core processors, and turn off all but one GPC for low end users? Or would this be better addressed as a memory allocation issue?

As for performance, the GPU, or multi GPUs in any system I've used are always the performance LIMFAC. They just arn't fast enough in any configuration.

JMTC

 

[Urwumpe]

I don't have hard data to prove this, but I think the graphics are by far the limiting factor in performance right now. Even during loading, e.g. SSU vs DG, there's a huge difference as SSU has to load many more meshes and textures. I'm not complaining, it's just the way it is. :shrug:

I can confirm this - especially since I still work hard on shoving the GPC stuff into a worker thread in the background to relax the delays a bit. CPU heavy computations can be taxing, yes, but they are still the least of our worries. For example using bitmap operations on dynamic textures is one of the worst framerate killers.

 

[Wolf]

Topic: SSU Deorbit and reentry

I am trying to check how accurate is SSU reentry (keeping in mind you told me this phase has not been fine tuned yet)

So this is what I have done:

STS-131 reentry analysis

1) took all the official data from NASASPACEFLIGHT.com forum and other docs like Space Shuttle Mission Summary:
DEORBIT BURN 04/20/2010 AT 12:02:59 UTC
LAND at KSC RWY33
POST BURN ORBIT 190X14 NM
R.E.I.= 4480
E.I. speed = 25860 fps

SSU simulation:
- Reentry scenario taken from David413 STS-131 deorbit (orbit parameters match with real ones)
- TIG at same time and pos as per real data; DVtot -297 fps resulting in a post burn orbit of 190x14 NM.

SSU reaches E.I. at 5422 NM from KSC, way too far, leading to a very low energy state which makes it impossible to reach the landing site.

In order to get the proper range at E.I. (between 4200 and 4400 NM) SSU needs to delay the deorbit burn well after the real Shuttle, much closer to the landing site.

Is this correct?

 

[GLS]

Topic: SSU Deorbit and reentry

I am trying to check how accurate is SSU reentry (keeping in mind you told me this phase has not been fine tuned yet)

So this is what I have done:

STS-131 reentry analysis

1) took all the official data from NASASPACEFLIGHT.com forum and other docs like Space Shuttle Mission Summary:
DEORBIT BURN 04/20/2010 AT 12:02:59 UTC
LAND at KSC RWY33
POST BURN ORBIT 190X14 NM
R.E.I.= 4480
E.I. speed = 25860 fps

SSU simulation:
- Reentry scenario taken from David413 STS-131 deorbit (orbit parameters match with real ones)
- TIG at same time and pos as per real data; DVtot -297 fps resulting in a post burn orbit of 190x14 NM.

SSU reaches E.I. at 5422 NM from KSC, way too far, leading to a very low energy state which makes it impossible to reach the landing site.

In order to get the proper range at E.I. (between 4200 and 4400 NM) SSU needs to delay the deorbit burn well after the real Shuttle, much closer to the landing site.

Is this correct?

If the orbit and the dV are correct, then I can't see how we could mess it up in free flight. :shrug:
Did you did the deorbit burn, are you sure you make it do a certain dV and not burn duration? If the mass is lower (because of no payload) the same burn time would create a larger dV, thus the vehicle would fall faster into the atmosphere, leading to a larger range at EI.

 

[Wolf]

The DVtot I used is base on the target HP (14NM)and NOT on burn time (TGO) so it should be correct.
Here is some pics where you can compare actual reentry data vs SSU

135 data Pre burn:


and post burn: SSU orbit in the scenario is very close to the real one


SSU at Deorbit Burn




and post Burn


135 Entry interface


SSU Entry Interface

Maybe from the screenshot above it's not readable but SSU Range at E.I. is around 5440 NM. That is 1000 NM too early!

So something wrong happens during reentry here...

I have done several succesful reentries hitting E.I. at the correct range from landing site (around 4200 nm) and with SSU AFCS handling the profile nicely on energy all the way down to preflare but in all cases I had to perform the de-orbit burn well closer to the site compared to the actual missions

This is the STS-131 entry scenario. Can anyone test it please?

BEGIN_DESC
Scenario at 20/04/2010 12.00 UTC
Deorbit burn was at 12:02:59 UTC over pacific Ocean approaching Port-aux-Francais island.
Landing at KSC RWY33 at 13:08:34 UTC
END_DESC

BEGIN_ENVIRONMENT
  System Sol
  Date MJD 55306.500000
END_ENVIRONMENT

BEGIN_FOCUS
  Ship Discovery
END_FOCUS

BEGIN_CAMERA
  TARGET Discovery
  MODE Cockpit
  FOV 40.00
END_CAMERA

BEGIN_HUD
  TYPE Surface
END_HUD

BEGIN_MFD Left
  TYPE User
  MODE CRT
END_MFD

BEGIN_MFD Right
  TYPE User
  MODE CRT
END_MFD

BEGIN_MFD 3
  TYPE User
  MODE CRT
END_MFD

BEGIN_MFD 4
  TYPE User
  MODE CRT
END_MFD

BEGIN_MFD 5
  TYPE User
  MODE CRT
END_MFD

BEGIN_MFD 6
  TYPE User
  MODE CRT
END_MFD

BEGIN_MFD 7
  TYPE User
  MODE CRT
END_MFD

BEGIN_MFD 9
  TYPE Map
  REF Earth
END_MFD

BEGIN_MFD 10
  TYPE User
  MODE CRT
END_MFD

BEGIN_VC
END_VC

BEGIN_SHIPS
Discovery:SpaceShuttleUltra
  STATUS Orbiting Earth
  ELEMENTS 6713469.28188936 0.00170530 74.61404257 169.39370552 307.20267097 87.90777097 55306.43760400
  AROT 16.39 -41.07 14.84
  VROT -0.08 -0.00 -0.00
   AFCMODE 7
  PRPLEVEL 0:0.455555 1:0.683559 2:0.769312 3:0.769496 4:1.000000 5:0.992000 6:0.334776 7:0.410000 8:0.410000 9:0.030000
  NAVFREQ 0 0
  MISSION STS-135
  CONFIGURATION 3
  VC_POS 0
  GEAR 0 0.0000
  OPS 302
  PLB_CAM 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
@SUBSYSTEM HeEng_C
  PRESS 1456.198154
  VALVES 1.000000 1.000000 0.000000 0.000000
@ENDSUBSYSTEM		;HeEng_C
@SUBSYSTEM HeEng_L
  PRESS 1456.175371
  VALVES 1.000000 1.000000 0.000000 0.000000
@ENDSUBSYSTEM		;HeEng_L   
@SUBSYSTEM HeEng_R
  PRESS 1456.206242
  VALVES 1.000000 1.000000 0.000000 0.000000
@ENDSUBSYSTEM		;HeEng_R
@SUBSYSTEM HePneu
  PRESS 1494.743770
  VALVES 1.000000 1.000000 0.000000
@ENDSUBSYSTEM		;HePneu
@SUBSYSTEM MPS
@ENDSUBSYSTEM		;MPS
@SUBSYSTEM MPS_C
  SSME config 5
  VIE config 2
  DCU_chA config 0
  DCU_chB config 0
  CIE_chA config 2
  CIE_chB config 2
@ENDSUBSYSTEM		;MPS_C
@SUBSYSTEM MPS_L
  SSME config 5
  VIE config 2
  DCU_chA config 0
  DCU_chB config 0
  CIE_chA config 2
  CIE_chB config 2
@ENDSUBSYSTEM		;MPS_L
@SUBSYSTEM MPS_R
  SSME config 5
  VIE config 2
  DCU_chA config 0
  DCU_chB config 0
  CIE_chA config 2
  CIE_chB config 2
@ENDSUBSYSTEM		;MPS_R
@SUBSYSTEM FMC1
@ENDSUBSYSTEM		;FMC1
@SUBSYSTEM FMC2
@ENDSUBSYSTEM		;FMC2
@SUBSYSTEM FMC3
@ENDSUBSYSTEM		;FMC3
@SUBSYSTEM MMC1
@ENDSUBSYSTEM		;MMC1
@SUBSYSTEM MMC2
@ENDSUBSYSTEM		;MMC2
@SUBSYSTEM MMC3
@ENDSUBSYSTEM		;MMC3
@SUBSYSTEM MMC4
@ENDSUBSYSTEM		;MMC4
@SUBSYSTEM AMC1
@ENDSUBSYSTEM		;AMC1
@SUBSYSTEM AMC2
@ENDSUBSYSTEM		;AMC2
@SUBSYSTEM AMC3
@ENDSUBSYSTEM		;AMC3
@SUBSYSTEM FF1
@ENDSUBSYSTEM		;FF1
@SUBSYSTEM FF2
@ENDSUBSYSTEM		;FF2
@SUBSYSTEM FF3
@ENDSUBSYSTEM		;FF3
@SUBSYSTEM FF4
@ENDSUBSYSTEM		;FF4
@SUBSYSTEM FA1
@ENDSUBSYSTEM		;FA1
@SUBSYSTEM FA2
@ENDSUBSYSTEM		;FA2
@SUBSYSTEM FA3
@ENDSUBSYSTEM		;FA3
@SUBSYSTEM FA4
@ENDSUBSYSTEM		;FA4
@SUBSYSTEM PL1
@ENDSUBSYSTEM		;PL1
@SUBSYSTEM PL2
@ENDSUBSYSTEM		;PL2
@SUBSYSTEM LF1
@ENDSUBSYSTEM		;LF1
@SUBSYSTEM LM1
@ENDSUBSYSTEM		;LM1
@SUBSYSTEM LA1
@ENDSUBSYSTEM		;LA1
@SUBSYSTEM OF1
@ENDSUBSYSTEM		;OF1
@SUBSYSTEM OF2
@ENDSUBSYSTEM		;OF2
@SUBSYSTEM OF3
@ENDSUBSYSTEM		;OF3
@SUBSYSTEM OF4
@ENDSUBSYSTEM		;OF4
@SUBSYSTEM OA1
@ENDSUBSYSTEM		;OA1
@SUBSYSTEM OA2
@ENDSUBSYSTEM		;OA2
@SUBSYSTEM OA3
@ENDSUBSYSTEM		;OA3
@SUBSYSTEM LL1
@ENDSUBSYSTEM		;LL1
@SUBSYSTEM LL2
@ENDSUBSYSTEM		;LL2
@SUBSYSTEM LR1
@ENDSUBSYSTEM		;LR1
@SUBSYSTEM LR2
@ENDSUBSYSTEM		;LR2
@SUBSYSTEM EIU1
@ENDSUBSYSTEM		;EIU1
@SUBSYSTEM EIU2
@ENDSUBSYSTEM		;EIU2
@SUBSYSTEM EIU3
@ENDSUBSYSTEM		;EIU3
@SUBSYSTEM MTU
  MET_RUNNING 1
  MET0 1354824.000000
  MET1 1354824.000000
  MET2 1354824.000000
EVENT_TIMER0 0.000000 DOWN STOPPED
EVENT_TIMER1 0.000000 DOWN STOPPED
@ENDSUBSYSTEM		;MTU
@SUBSYSTEM IDP1
  IDP1 SPEC 65535
  IDP1 DISP 65535
@ENDSUBSYSTEM		;IDP1
@SUBSYSTEM IDP2
  IDP2 SPEC 65535
  IDP2 DISP 65535
@ENDSUBSYSTEM		;IDP2
@SUBSYSTEM IDP3
  IDP3 SPEC 65535
  IDP3 DISP 19
@ENDSUBSYSTEM		;IDP3
@SUBSYSTEM IDP4
  IDP4 SPEC 65535
  IDP4 DISP 65535
@ENDSUBSYSTEM		;IDP4
@SUBSYSTEM IMU1
@ENDSUBSYSTEM		;IMU1
@SUBSYSTEM IMU2
@ENDSUBSYSTEM		;IMU2
@SUBSYSTEM IMU3
@ENDSUBSYSTEM		;IMU3
@SUBSYSTEM GPC1
@ENDSUBSYSTEM		;GPC1
@SUBSYSTEM GPC2
@ENDSUBSYSTEM		;GPC2
@SUBSYSTEM GPC3
@ENDSUBSYSTEM		;GPC3
@SUBSYSTEM GPC4
@ENDSUBSYSTEM		;GPC4
@SUBSYSTEM GPC5
@ENDSUBSYSTEM		;GPC5
@SUBSYSTEM MMU1
@ENDSUBSYSTEM		;MMU1
@SUBSYSTEM MMU2
@ENDSUBSYSTEM		;MMU2
@SUBSYSTEM SimpleGPCSystem
  @BEGINSOFTWARE OrbitDAP
  TGT_ID 2
  BODY_VECT 1
  ROLL 0.000000
  PITCH 0.000000
  YAW 0.000000
  P_ANGLE 0.000000
  Y_ANGLE 0.000000
  OM_ANGLE -1.000000
  DAP_MODE 0 0
  ROT_MODE 0 0 0
  TRANS_MODE 0 0 0
  CONTROL_MODE 1
  CUR_MNVR 0 -0.604096 0.553426 -2.006825
  @ENDSOFTWARE 
  @BEGINSOFTWARE StateVectorSoftware
  @ENDSOFTWARE 
  @BEGINSOFTWARE OMSBurnSoftware
  @ENDSOFTWARE 
  @BEGINSOFTWARE AerojetDAP
  SITE_ID 0
  SIDE L
  ENTRY_GUIDANCE 0
  TAEM_GUIDANCE 0
  SB_CONTROL_LOGIC 0
  @ENDSOFTWARE 
  @BEGINSOFTWARE IO_Control
  @ENDSOFTWARE 
  @BEGINSOFTWARE ATVC_SOP
  CONFIG 2
  @ENDSOFTWARE 
  @BEGINSOFTWARE GeneralDisplays
  @ENDSOFTWARE 
  @BEGINSOFTWARE RHC_RM
  @ENDSOFTWARE 
  @BEGINSOFTWARE THC_RM
  @ENDSOFTWARE 
  @BEGINSOFTWARE RHC_SOP
  @ENDSOFTWARE 
  @BEGINSOFTWARE THC_SOP
  @ENDSOFTWARE 
@ENDSUBSYSTEM		;SimpleGPCSystem
@SUBSYSTEM ADPS
  LEFT_AIRDATAPROBE 1 3 0.000000
  RIGHT_AIRDATAPROBE 1 3 0.000000
@ENDSUBSYSTEM		;ADPS
@SUBSYSTEM ETUmbDoors
  ET_DOORS 0.000000 0.000000
  ET_DOOR_LATCHES 1.000000 0.000000 0.000000
@ENDSUBSYSTEM		;ETUmbDoors
@SUBSYSTEM -YStarTrackerDoorMotor
@ENDSUBSYSTEM		;-YStarTrackerDoorMotor
@SUBSYSTEM -ZStarTrackerDoorMotor
@ENDSUBSYSTEM		;-ZStarTrackerDoorMotor
@SUBSYSTEM ACBusSystem
@ENDSUBSYSTEM		;ACBusSystem
@SUBSYSTEM INVERTER1
@ENDSUBSYSTEM		;INVERTER1
@SUBSYSTEM INVERTER2
@ENDSUBSYSTEM		;INVERTER2
@SUBSYSTEM INVERTER3
@ENDSUBSYSTEM		;INVERTER3
@SUBSYSTEM GCIL
@ENDSUBSYSTEM		;GCIL
@SUBSYSTEM ATVC
@ENDSUBSYSTEM		;ATVC
@SUBSYSTEM MEC1
@ENDSUBSYSTEM		;MEC1
@SUBSYSTEM MEC2
@ENDSUBSYSTEM		;MEC2
@SUBSYSTEM RA1
@ENDSUBSYSTEM		;RA1
@SUBSYSTEM RA2
@ENDSUBSYSTEM		;RA2
@SUBSYSTEM PayloadBay
  DOOR_PORT 0 0.0000
  DOOR_STBD 0 0.0000
  RADIATOR_PORT 0 0.0000
  RADIATOR_STBD 0 0.0000
  RADLATCH_PORT 0 0.0000
  RADLATCH_STBD 0 0.0000
  DOORLATCH0 0 0.0000
  DOORLATCH1 0 0.0000
  DOORLATCH2 0 0.0000
  DOORLATCH3 0 0.0000
  DOORLATCH4 0 0.0000
  DOORLATCH5 0 0.0000
  DOORLATCH6 0 0.0000
  DOORLATCH7 0 0.0000
  KUBAND 0 0.0000
@ENDSUBSYSTEM		;PayloadBay
@SUBSYSTEM APU1
  APU1_State 0
  APU1_FuelPress 0.000000
  APU1_HydPress 0.00000
  APU1_Speed 0.000000
@ENDSUBSYSTEM		;APU1
@SUBSYSTEM APU2
  APU2_State 0
  APU2_FuelPress 0.000000
  APU2_HydPress 0.000000
  APU2_Speed 0.000000
@ENDSUBSYSTEM		;APU2
@SUBSYSTEM APU3
  APU3_State 0
  APU3_FuelPress 0.000000
  APU3_HydPress 0.000000
  APU3_Speed 0.000000
@ENDSUBSYSTEM		;APU3
@SUBSYSTEM WSB1
@ENDSUBSYSTEM		;WSB1
@SUBSYSTEM WSB2
@ENDSUBSYSTEM		;WSB2
@SUBSYSTEM WSB3
@ENDSUBSYSTEM		;WSB3
@SUBSYSTEM LATCH0
  LATCH_STATE1 1 1.0000
  LATCH_STATE2 1 1.0000
  LATCH_STATE3 1 1.0000
  LATCH_STATE4 1 1.0000
  LATCH_STATE5 1 1.0000
@ENDSUBSYSTEM		;LATCH0
@SUBSYSTEM LATCH1
  LATCH_STATE1 1 1.0000
  LATCH_STATE2 1 1.0000
  LATCH_STATE3 1 1.0000
  LATCH_STATE4 1 1.0000
  LATCH_STATE5 1 1.0000
@ENDSUBSYSTEM		;LATCH1
@SUBSYSTEM LATCH2
  LATCH_STATE1 1 1.0000
  LATCH_STATE2 1 1.0000
  LATCH_STATE3 1 1.0000
  LATCH_STATE4 1 1.0000
  LATCH_STATE5 1 1.0000
@ENDSUBSYSTEM		;LATCH2
@SUBSYSTEM PRSD
  LV011 1.000000
  LV021 1.000000
  LV031 1.000000
  LV041 1.000000
  LV013 1.000000
  LV023 1.000000
  LV024 1.000000
  LV033 1.000000
  LV043 1.000000
  LV044 1.000000
  LV012 1.000000
  LV022 1.000000
@ENDSUBSYSTEM		;PRSD
@SUBSYSTEM VideoControlUnit
  CAMERA_POWER 0 0 0 0 0
  OUTPUT 0
  INPUTS 0 0 0 0 0 0 0 0
@ENDSUBSYSTEM		;VideoControlUnit
@SUBSYSTEM ACA1
@ENDSUBSYSTEM		;ACA1
@SUBSYSTEM ACA2
@ENDSUBSYSTEM		;ACA2
@SUBSYSTEM ACA3
@ENDSUBSYSTEM		;ACA3
@SUBSYSTEM ACA4
@ENDSUBSYSTEM		;ACA4
@SUBSYSTEM ACA5
@ENDSUBSYSTEM		;ACA5
@SUBSYSTEM RMS
  ARM_STATUS 0.500000 0.013600 0.014688 0.500000 0.500000 0.500000
  SHOULDER_BRACE 0.000000
  GRAPPLE 1 1.0000
  RIGIDIZE 1 1.0000
  EXTEND 1 1.0000
  RMS_ELBOW_CAM 0.0000 0.0000
  RMS_ROLLOUT 0 0.0000
  RMS_LATCHES 1 1.0000
@ENDSUBSYSTEM		;RMS
@SUBSYSTEM STBD_MPM
  STBD_MPM_ROLLOUT 0 0.0000
  STBD_MPM_LATCHES 1 1.0000
@ENDSUBSYSTEM		;STBD_MPM
@SUBSYSTEM ODS
  RING_STATE -1 0.0000
@ENDSUBSYSTEM		;ODS
@SUBSYSTEM DeployedAssembly
  ALPHA 124.300000
  BETA -27.500000
@ENDSUBSYSTEM		;DeployedAssembly
@SUBSYSTEM ElectronicsAssembly1
@ENDSUBSYSTEM		;ElectronicsAssembly1
@SUBSYSTEM ElectronicsAssembly2
@ENDSUBSYSTEM		;ElectronicsAssembly2
@SUBSYSTEM DragChute
@ENDSUBSYSTEM		;DragChute
  @PANEL F2
  "Drag Chute ARM Cover" [0]
  "Drag Chute DPY Cover" [0]
  "HUD Mode" NORM
  "HUD Brightness" [2]
  "HUD Bright" AUTO
  @ENDPANEL 
  @PANEL F3
  "Drag Chute ARM Cover" [0]
  "Drag Chute DPY Cover" [0]
  "Drag Chute JETT Cover" [0]
  "HUD Power CDR" OFF
  "HUD Power PLT" OFF
  @ENDPANEL 
  @PANEL F4
  "Drag Chute JETT Cover" [0]
  "HUD Mode" NORM
  "HUD Brightness" [2]
  "HUD Bright" AUTO
  @ENDPANEL 
  @PANEL F6
  @OBJECT "CDR1"
  DISPLAY 3
  MENU 2
  BRIGHTNESS 0.800000
  @ENDOBJECT
  @OBJECT "CDR2"
  DISPLAY 1
  MENU 1
  BRIGHTNESS 0.800000
  @ENDOBJECT
  "Cdr Flt Cntlr Pwr" ON
  "ADI Attitude" INRTL
  "ADI Error" MED
  "ADI Rate" MED
  "Landing Gear ARM Cover" [0]
  "Landing Gear DN Cover" [0]
  @ENDPANEL 
  @PANEL F7
  @OBJECT "CRT1"
  DISPLAY 0
  MENU 3
  BRIGHTNESS 0.800000
  @ENDOBJECT
  @OBJECT "CRT2"
  DISPLAY 0
  MENU 3
  BRIGHTNESS 0.800000
  @ENDOBJECT
  @OBJECT "CRT3"
  DISPLAY 0
  MENU 3
  BRIGHTNESS 0.800000
  @ENDOBJECT
  @OBJECT "MFD1"
  DISPLAY 5
  MENU 2
  BRIGHTNESS 0.800000
  @ENDOBJECT
  @OBJECT "MFD2"
  DISPLAY 3
  MENU 2
  BRIGHTNESS 0.800000
  @ENDOBJECT
  @ENDPANEL 
  @PANEL F8
  @OBJECT "PLT1"
  DISPLAY 1
  MENU 1
  BRIGHTNESS 0.800000
  @ENDOBJECT
  @OBJECT "PLT2"
  DISPLAY 4
  MENU 2
  BRIGHTNESS 0.800000
  @ENDOBJECT
  "Plt Flt Cntlr Pwr" OFF
  "ADI Attitude" INRTL
  "ADI Error" MED
  "ADI Rate" MED
  "Landing Gear ARM Cover" [0]
  "Landing Gear DN Cover" [0]
  @ENDPANEL 
  @PANEL L1
  "Fire Suppression Av Bay 1 Disch Agent Cover" [0]
  "Fire Suppression Av Bay 2 Disch Agent Cover" [0]
  "Fire Suppression Av Bay 3 Disch Agent Cover" [0]
  @ENDPANEL 
  @PANEL C2
  "IDP/CRT 1 Power" ON
  "IDP/CRT 2 Power" ON
  "IDP/CRT 3 Power" ON
  "IDP/CRT 1 Maj Func" GNC
  "IDP/CRT 2 Maj Func" GNC
  "IDP/CRT 3 Maj Func" GNC
  "Left CRT Sel" 1
  "Right CRT Sel" 2
  "Event Timer Mode" Down
  @ENDPANEL 
  @PANEL C3
  "LOMS Arm" ARM/PRESS
  "ROMS Arm" ARM/PRESS
  "BFC CRT Display" ON
  "BFC CRT Select" 3+1
  "LADP Stow Enable" INHIBIT
  "RADP Stow Enable" INHIBIT
  "LADP Deploy" STOW
  "RADP Deploy" STOW
  "MAIN ENGINE LIMIT SHUT DN" AUTO
  "SSME Left S/D PB Cover" [0]
  "SSME Ctr S/D PB Cover" [0]
  "SSME Right S/D PB Cover" [0]
  "SRB Separation" AUTO
  "SRB Separation PB Cover" [0]
  "ET Separation" AUTO
  "ET Separation PB Cover" [0]
  @ENDPANEL 
  @PANEL R2
  "Boiler1 N2 Supply" ON
  "Boiler2 N2 Supply" ON
  "Boiler3 N2 Supply" ON
  "Boiler1 Power" ON
  "Boiler2 Power" ON
  "Boiler3 Power" ON
  "Boiler1 Cntlr/Htr" A
  "Boiler2 Cntlr/Htr" A
  "Boiler3 Cntlr/Htr" A
  "APU1 Operate" START/RUN
  "APU2 Operate" OFF
  "APU3 Operate" OFF
  "Hyd Main Pump Press 1" LOW
  "Hyd Main Pump Press 2" LOW
  "Hyd Main Pump Press 3" LOW
  "APU1 Cntlr Pwr" ON
  "APU2 Cntlr Pwr" ON
  "APU3 Cntlr Pwr" ON
  "APU1 Fuel Tank Valve" OPEN
  "APU2 Fuel Tank Valve" CLOSE
  "APU3 Fuel Tank Valve" CLOSE
  "ET Umb Centerline Latch" GND
  "ET Umb Left Door" OFF
  "ET Umb Left Door Latch" OFF
  "ET Umb Right Door" OFF
  "ET Umb Right Door Latch" OFF
  "MPS Pwr Left AC2" [0]
  "MPS Pwr Ctr AC1" [0]
  "MPS Pwr Right AC3" [0]
  "MPS Pwr Left AC3" [0]
  "MPS Pwr Ctr AC2" [0]
  "MPS Pwr Right AC1" [0]
  "MPS He Isol A Left" GPC
  "MPS He Isol A Ctr" GPC
  "MPS He Isol A Right" GPC
  "MPS He Isol B Left" GPC
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END
END_SHIPS

BEGIN_ExtMFD
END

 

[GLS]

The DVtot I used is base on the target HP (14NM)and NOT on burn time (TGO) so it should be correct.
Here is some pics where you can compare actual reentry data vs SSU

135 data Pre burn:
View attachment 15482

and post burn: SSU orbit in the scenario is very close to the real one
View attachment 15481

SSU at Deorbit Burn
View attachment 15483

and post Burn
View attachment 15484

135 Entry interface
View attachment 15486

SSU Entry Interface
View attachment 15485
Maybe from the screenshot above it's not readable but SSU Range at E.I. is around 5440 NM. That is 1000 NM too early!

So something wrong happens during reentry here...

I can't see what... nothing happens during that coast to EI. Could you try with another vessel (e.g. DG)?

 

[Wolf]

I can't see what... nothing happens during that coast to EI. Could you try with another vessel (e.g. DG)?

Sorry what do you mean by "nothing happens.."

Above you can find the scenario attached: would you be happy to give it a try?

 

[GLS]

Sorry what do you mean by "nothing happens.."

Above you can find the scenario attached: would you be happy to give it a try?

SSU does nothing... it's "Mr. Newton in the driver's seat". So my bet is on the data you are using being wrong... but it could also be our OMS burns aren't correct.

 

[DaveS]

SSU does nothing... it's "Mr. Newton in the driver's seat". So my bet is on the data you are using being wrong... but it could also be our OMS burns aren't correct.

Given that we're getting large residuals way out side the official SSP specs, I concur with that. Currently our OMS is in the need of a serious overhaul. Here's the official ticket for it: https://sourceforge.net/p/shuttleultra/tickets/95/

We've had for two-a-half years now, so I think it's time.

 

[GLS]

Another thing: are we talking STS-131 or 135?

 

[Wolf]

SSU does nothing... it's "Mr. Newton in the driver's seat". So my bet is on the data you are using being wrong... but it could also be our OMS burns aren't correct.

Yes but what is supposed to happen between deorbit and E.I.: AFAIK the Shuttle does nothing eccept re orienting herself for the proper E.I. attitude.
there is no drag above 400k feet so what else should happen?

Yes we are talking about STS-131. Sorry I wrote 135 commenting the screenshots, my mistake

 

[Urwumpe]

Yes but what is supposed to happen between deorbit and E.I.: AFAIK the Shuttle does nothing eccept re orienting herself for the proper E.I. attitude.
there is no drag above 400k feet so what else should happen?

Yes we are talking about STS-131. Sorry I wrote 135 commenting the screenshots, my mistake

How is your orbit after the deorbit burn?

 

[GLS]

Yes but what is supposed to happen between deorbit and E.I.: AFAIK the Shuttle does nothing eccept re orienting herself for the proper E.I. attitude.
there is no drag above 400k feet so what else should happen?

Yes we are talking about STS-131. Sorry I wrote 135 commenting the screenshots, my mistake

Nothing (apart from the turn) should happen, so either the trajactory data is wrong, or SSU isn't doing the OMS burn correctly, which although it currently isn't perfect, if the perigee matches IMO it means it isn't that bad. :shrug: So that leaves the trajectory data.
Another source of problems is off-plane deorbit burn, something that was done sometimes to dump OMS prop. It seems that it isn't the case here, as the perigee matches after the dV.

 

[Wolf]

How is your orbit after the deorbit burn?

If you mean HA and HP I have got 190x14 nm as CRT1 shows in the post burn screenshot. That matches with real data.
So I am getting confused now:
Assuming the data I used are correct, if I do the burn exactly at the same point it was done in real life, with last orbit being the same as the real one and with same HA and HP, targeting a burn (Dv) that gives me the desired HP (again taken by real data) how comes SSU reaches EI that early and so far from the desired Range? From post burn to EI, as you confirmed, nothing happens and no factor can influence the trajectory since the shuttle simply loses altitude in a virtual no-drag environment. My guess is the re entry angle resulting from the burn is steeper than it should be hence SSU descends from orbit altitude to 120 km in a much shorter distance then it should (as the scenario shows cimpared to the real EI point)

 

[Urwumpe]

If you mean HA and HP I have got 190x14 nm as CRT1 shows in the post burn screenshot.

I mean in Orbiter. I would not trust our displays further than I can throw an equivalent hardware.... and a GPC is a heavy thing.

Generally, the numbers are right in SSU, but if you really depend on them, they will be wrong. I call this my dualism law of SSU.

 

[Wolf]

Nothing (apart from the turn) should happen, so either the trajactory data is wrong, or SSU isn't doing the OMS burn correctly, which although it currently isn't perfect, if the perigee matches IMO it means it isn't that bad. :shrug: So that leaves the trajectory data.
Another source of problems is off-plane deorbit burn, something that was done sometimes to dump OMS prop. It seems that it isn't the case here, as the perigee matches after the dV.

As said above, if the burn is good nd it’s done at the correct point, what could csuse the trajectory data to be wrong? The L2 website data MUST be correct since they were taken realtime from NASA source during reentry, so I wonder why the discrepancy at EI is so huge..

---------- Post added at 11:18 PM ---------- Previous post was at 11:13 PM ----------

I mean in Orbiter. I would not trust our displays further than I can throw an equivalent hardware.... and a GPC is a heavy thing.

Generally, the numbers are right in SSU, but if you really depend on them, they will be wrong. I call this my dualism law of SSU.

In other words you mean that if we target and do a burn that results in the desired HP value we cannot rely on that?
So to get a proper reentry path will need a lot of trial and error?
Sorry I missed that you ment Orbiter values: yes I crosschecked with orbit MFD and the values match (HP is around 25 Km)