OHM NTR core propulsion stage

[Wishbone]

Somebody has got a buggy re-getter, it seems. On the punch stack: reading on cross-product powered flight guidance (from the Colossus R-577 manual), since IMFD won't handle burns with this stage.

 

[jgrillo2002]

Found a little hiccup but maybe its just me. I run this scenario. it comes with the Mars DRM addon

BEGIN_DESC

END_DESC

BEGIN_ENVIRONMENT
  System Sol
  Date MJD 54364.0
END_ENVIRONMENT

BEGIN_FOCUS
  Ship NTR2
END_FOCUS

BEGIN_CAMERA
  TARGET NTR1
  MODE Extern
  POS 17.86 -122.26 -153.31
  TRACKMODE TargetRelative
  FOV 50.00
END_CAMERA

BEGIN_HUD
  TYPE Surface
END_HUD

BEGIN_MFD Right
  TYPE Orbit
  PROJ Ship
  FRAME Ecliptic
  ALT
  REF Earth
END_MFD

BEGIN_SHIPS
cargolander:DRM1_cargo
  STATUS Orbiting Earth
  RPOS -1517895.81 5375395.35 -3521953.31
  RVEL -1856.257 -4471.570 -6080.519
  AROT -24.34 34.97 -3.58
  VROT 0 0 0
  DOCKINFO 1:0,Tank1
  AFCMODE 7
  PRPLEVEL 0:0.765645
  NAVFREQ 0 0
  CONFIG 1 1 1 2
  UCGO @@0,1,1,9000,CargoFissionReactorAuto,@@1,1,1,100,CargoSolarBalloonAuto,@@2,1,1,100,CargoWeatherBalloonAuto,
  UCGO @@3,1,1,3217,CargoBaseControl,@@4,1,1,567,CargoBaseConnect,@@5,1,1,2874,CargoBaseModule,  
  UCGO @@6,1,1,2874,CargoBaseModule,@@7,1,1,2874,CargoBaseModule,
END
NTR1:NTR_test
  STATUS Orbiting Earth
  RPOS -1517895.81 5375395.35 -3521953.31
  RVEL -1856.257 -4471.570 -6080.519
  AROT -24.34 34.97 -3.58
  VROT 0 0 0
  DOCKINFO 0:1,Tank1 1:1,cargolander
  PRPLEVEL 0:1.0
END
Tank1:NTR_inlinetank
  STATUS Orbiting Earth
  RPOS -1517895.81 5375395.35 -3521953.31
  RVEL -1856.257 -4471.570 -6080.519
  AROT -24.34 34.97 -3.58
  VROT -0.19 -0.05 5.43
  AFCMODE 7
  PRPLEVEL 0:1.000000 1:1.000000
  DOCKINFO 1:0,NTR1
  IDS 0:522 100 1:523 100
  NAVFREQ 0 0
  XPDR 518
  ANIMATION 0 0 1
  ANIMATION 1 0 1
END
habitatlander:DRM1_hab
  STATUS Orbiting Earth
  RPOS -1517795.81 5375395.35 -3521953.31
  RVEL -1856.257 -4471.570 -6080.519
  AROT -24.34 34.97 -3.58
  VROT 0 0 0
  DOCKINFO 1:0,Tank2
  AFCMODE 7
  PRPLEVEL 0:0.765645
  NAVFREQ 0 0
  CONFIG 1 1 2
END
NTR2:NTR_test
  STATUS Orbiting Earth
  RPOS -1517795.81 5375395.35 -3521953.31
  RVEL -1856.257 -4471.570 -6080.519
  AROT -24.34 34.97 -3.58
  VROT 0 0 0
  DOCKINFO 0:1,Tank2 1:1,habitatlander
  PRPLEVEL 0:1.0
  THRUST 0
END
Tank2:NTR_inlinetank
  STATUS Orbiting Earth
  RPOS -1517795.81 5375395.35 -3521953.31
  RVEL -1856.257 -4471.570 -6080.519
  AROT -24.34 34.97 -3.58
  VROT -0.19 -0.05 5.43
  AFCMODE 7
  PRPLEVEL 0:1.000000 1:1.000000
  DOCKINFO 1:0,NTR2
  IDS 0:522 100 1:523 100
  NAVFREQ 0 0
  XPDR 518
  ANIMATION 0 0 1
  ANIMATION 1 0 1
END
END_SHIPS

The RCS doesnt work and I have no idea how to use the commands. I looked at the manual but it still doesnt make sense. can you provide me a small tutorial

 

[Wishbone]

STEADY RATE 0.010
SLOW RATE 0.005
AUTO RCS ENABLE
AUTO RCS LEVEL 1200
RCS PITCH PROP 20
RCS YAW PROP 20

The stack DAP is not perfect, to say the least. To avoid overshoots, you'll have to issue PDOT and YDOT commands, am afraid (or use up/down left/right arrow keys on the main keyboard).

In addition, there are suspected bugs with stack RCS optimization. To get the configuration to your taste you can issue AUTO RCS SET commands (look at the auto-generated strings for inspiration, they are basically vessel, number of the thruster and thruster setting). Power steering works much better (just be sure to issue STEADY RATE 1.0 for quick convergence).

 

[jaydog]

Hey wishbone! Thanks for the NTR mod, I created a series of scenarios using yours and francis drakes CEV-LM mods and posted them to orbit hanger. Its called Direct_to_Mars Anyone have any suggestions for improvement or added / changed scenarios let me know, should be approved within next day as its my first upload try.
Thanks! Jaydog

 

[Frin63]

Very nice addon Wishbone! Some years ago I designed a BNTR stage for SimNASA myself, but I didn't get to this level of simulation. I very much like the way the engine startup and cooldown is implemented.

There is a problem IMHO with the Xe135 poisoning though. It's now implemented (I beleive) as being 100% after a burn and the steadily decreasing. In reality it will be almost 0% directly after the burn but increasing after that (due to the decay of Iodine-135 that has been produced during the fission). It will reach a peak about 10 hours after the burn (height of the peak will be dependent on burn duration) and then start to fall off to 0 again. This has some implications for multiple burns for instance for a Trans Mars Injection: You could perhaps still start the engine at the next perigee after an orbit of 3 hours, but not after an orbit of 10 hours.

If you like I can work out this model a bit further.
Nice link with enlighting graphic on this subject: [ame="http://en.wikipedia.org/wiki/Iodine_pit"]Iodine pit - Wikipedia, the free encyclopedia[/ame]

Best Regards! Frank.

 

[Wishbone]

Frank,

Work backlog prevents me from perfecting & updating the add-on (work mostly on Linux w/o any simulations/games ). Would be nice if you could fork the development as, say, NTR Mark II.

Cheers,

Wishbone

 

[edition23]

Is there a knack for for getting the rcs under control? I love the attention to detail on this but I'm having a hard time centering my BV in IMFD. I'm not using the auto burn. Sometimes it doesn't seem to respond at all. I only have the Malerba inflatable module 2.0 docked to it. I've read the manual a few times but I don't fully comprehend the DAP settings. (Prop, Int, Deriv, Minout, Maxout ect.) If anyone could help me off in the right direction I'd be appreciative. I know nobody's posted in awhile but I figured I'd give it a shot. Thanks.