Spacecraft3 landing points - small movements

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george7378

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Hi all,

I am having a slight problem with the landing points on a simple lunar lander I am making.

All the landing points are at the same co-ordinates in the up/down axis (length of legs is the same). When I place it on the Moon's surface, it is evident that the spacecraft is rocking back and forth very slowly, and if I use time acceleration, it starts to 'vibrate' and move around on the floor. It topples over into a spin when I increase time speed enough.

I have four landing points - is there a way to 'root' the craft to the floor, like the AMSO descent stage, becasue I have a feeling it it the planet's movement causing this, but I may be wrong.

Thanks.
 
Looking at Orbiter's API documentation, it would seem that a vessel should have only three touchdown points.

Try removing one of them and see what happens.
 
Thanks, but it is still the same :(
 
Are you sure that all of the engines are off?

Also, the landing points need to be defined so that (pt3 - pt1) x (pt2 - pt1) gives the correct up direction for the spacecraft.
 
I don't know about that, but MeshWizard defines the Y axis as up.
 
Can you give the SC3 .ini contents?

N.
 
Here it is:

Code: 
[CONFIG]
MESHNAME="Landertest"       
EMPTY_MASS=500
FUEL_MASS=1200
HOVER_THRUST=15000
ATTITUDE_THRUST=400
ISP=4000
PMI=(1.72,1.69,2.53)
CROSS_SECTION=(5.88,5.79,19.29)
CAMERA=(0,0,5.5)
SIZE=19.25
VISIBLE=0
LAND_PT1=(-1.36,-2.167386,1.607835)
LAND_PT2=(-0.51,-2.167386,-1.88)
LAND_PT3=(1.605,-2.167386,1.231)

[LANDING_GEAR]
WHEEL=200000
BELLY=200000
BRAKE=200000
SEQ=1

[EX_HOVER_0]
OFF=(0,-0.7595892,0)
DIR=(0,-1,0)
LENGTH=3
WIDTH=0.3

[EX_ATT_0]
OFF=(-0.1233788,0.6363645,2.196836)
DIR=(0,1,0)
LENGTH=0.5
WIDTH=0.05
ROT_AXIS=X
ROT_CW=1
LIN_AXIS=Y
LIN_CW=1

[EX_ATT_1]
OFF=(-0.1233788,0.6653936,-2.187424)
DIR=(0,1,0)
LENGTH=0.5
WIDTH=0.05
ROT_AXIS=X
ROT_CW=0
LIN_AXIS=Y
LIN_CW=1

[EX_ATT_2]
OFF=(2.173667,0.6653936,0.1152083)
DIR=(0,1,0)
LENGTH=0.5
WIDTH=0.05
ROT_AXIS=Z
ROT_CW=0
LIN_AXIS=Y
LIN_CW=1

[EX_ATT_3]
OFF=(-2.173667,0.6653936,0.1152083)
DIR=(0,1,0)
LENGTH=0.5
WIDTH=0.05
ROT_AXIS=Z
ROT_CW=1
LIN_AXIS=Y
LIN_CW=1

[EX_ATT_4]
OFF=(-0.1233788,0.6363645,2.196836)
DIR=(1,0,0)
LENGTH=0.5
WIDTH=0.05
ROT_AXIS=Y
ROT_CW=0
LIN_AXIS=X
LIN_CW=1

[EX_ATT_5]
OFF=(-0.1233788,0.6363645,-2.196836)
DIR=(-1,0,0)
LENGTH=0.5
WIDTH=0.05
ROT_AXIS=Y
ROT_CW=1
LIN_AXIS=X
LIN_CW=0

[ANIM_SEQ_0]
;LEGS
KEY=G
REPEAT=0
DURATION=30

[ANIM_COMP_0]
SEQ=0
GROUPS=2
RANGE=(0,1)
ROT_PNT=(2.372247,-1.033507,0) 
ROT_AXIS=(0,0,-1)
ANGLE=-115

[ANIM_COMP_1]
SEQ=0
GROUPS=3
RANGE=(0,1)
ROT_PNT=(-2.372247,-1.033507,0) 
ROT_AXIS=(0,0,-1)
ANGLE=115

[ANIM_COMP_2]
SEQ=0
GROUPS=5
RANGE=(0,1)
ROT_PNT=(0,-1.033507,-2.386935) 
ROT_AXIS=(-1,0,0)
ANGLE=-115

[ANIM_COMP_3]
SEQ=0
GROUPS=8
RANGE=(0,1)
ROT_PNT=(0.6973788,-1.034383,2.378905) 
ROT_AXIS=(-1,0,0)
ANGLE=115
 
Try these numbers

LAND_PT1=(0,-2.167386,1.607835)
LAND_PT2=(-1.605,-2.167386,-1.88)
LAND_PT3=(1.605,-2.167386,-1.88)
 
Thanks, but still the same...
 
Try setting the scenario with no propellent, you may have a thruster firing slighty.
 
I don't think you can that much difference between your X,Y and Z values in your LAND_PT's.

Here's some from the SC3 sample .ini's

GL-VH
LAND_PT1=(0,-2.57,9)
LAND_PT2=(-4,-2.57,-5)
LAND_PT3=(4,-2.57,-5)

Dpod2
LAND_PT1=(1.5,-2.162,1.59)
LAND_PT2=(-1.5,-2.162,1.59)
LAND_PT3=(0,-2.162,-1.59)

STS-102
LAND_PT1=(0,-4,17)
LAND_PT2=(-3.96,-5.6,-4.3)
LAND_PT3=(3.96,-5.6,-4.3)

and one of mine!
BlueStreak_F2
LAND_PT1=(0,-2.57,9)
LAND_PT2=(-4,-2.57,-5)
LAND_PT3=(4,-2.57,-5)

I think with your values, the vessels COG is not through the centre of the landing points, and you are generating a "moment" about those points.
In other words, its falling over! Might explain why its dancing about? Of course it might just be happy.

N.
 
Right - the zero propellant scenario worked, and I watched the fuel with the tanks full in the same scenario, and it was decreasing slightly.

Could it be because I haven't configured a full RCS in the INI yet?

---------- Post added at 04:57 PM ---------- Previous post was at 04:52 PM ----------

Maybe it's LOLA MFD? (even though it is disengaged).
 
You may have movement in the scenario.
 
george7378 said:


Maybe it's LOLA MFD? (even though it is disengaged).
Click to expand...

I think so, I've got the exact same problem. Even disengaged it's still trying to use the RCS thrusters for something. I can spot them still firing a little when I zoom the camera in.
 
Yes - when I lift off again, the craft keeps pitching forwards. I've a feeling it's the AP.

---------- Post added 11-07-09 at 08:19 AM ---------- Previous post was 11-06-09 at 09:38 PM ----------

Is there a way to avoid this, or another MFD I can use? How can I eliminate movement in the scenario?
 
delete them
 
Which lines would this be? Does this make the RCS fire? How can I fully disengage LOLA?
 
Here it is:

Code: 
BEGIN_DESC
Orbiter saved state at T = 5394
END_DESC

BEGIN_ENVIRONMENT
  System Sol
  Date MJD 55141.0743834305
END_ENVIRONMENT

BEGIN_FOCUS
  Ship Landertest
END_FOCUS

BEGIN_CAMERA
  TARGET Landertest
  MODE Extern
  POS 1.04 118.75 -4.44
  TRACKMODE TargetRelative
  FOV 40.00
END_CAMERA

BEGIN_HUD
  TYPE Surface
END_HUD

BEGIN_MFD Left
  TYPE Surface
  SPDMODE 1
END_MFD

BEGIN_MFD Right
  TYPE User
  MODE LolaMFD
END_MFD


BEGIN_SHIPS
Landertest:Spacecraft\Spacecraft3
  STATUS Orbiting Moon
  RPOS -440793.84 -65311.30 -1679906.84
  RVEL 4.466 0.032 -1.169
  AROT 113.02 -53.55 -25.27
  RCSMODE 2
  PRPLEVEL 0:0.309
  THLEVEL 5:0.002 6:0.002
  NAVFREQ 0 0
  RCS 1
  CTRL_SURFACE 1
  CONFIGURATION 1
  CURRENT_PAYLOAD 0
  SEQ 0 2 0.970900
END
ISS:ProjectAlpha_ISS
  STATUS Orbiting Earth
  RPOS -6607973.61 -147476.61 1322032.01
  RVEL -559.172 7405.671 -1981.804
  AROT -108.08 -7.35 -34.52
  VROT 0.10 -0.01 -0.02
  PRPLEVEL 0:1.000
  IDS 0:588 100 1:586 100 2:584 100 3:582 100 4:580 100
  NAVFREQ 0 0
  XPDR 466
END
Mir:Mir
  STATUS Orbiting Earth
  RPOS -1619077.76 395136.95 6460500.78
  RVEL -7498.679 -114.239 -1867.724
  AROT -142.48 -54.59 -111.29
  IDS 0:540 100 1:542 100 2:544 100
  XPDR 482
END
Luna-OB1:Wheel
  STATUS Orbiting Moon
  RPOS 1643681.76 1520647.78 -238.96
  RVEL -1004.839 1086.206 -0.203
  AROT 0.01 0.01 -146.42
  VROT 0.00 0.00 10.00
  IDS 0:560 100 1:564 100
  XPDR 494
END
Upton Village - Wing 1:DGIVPreludeII
  STATUS Landed Moon
  POS -93.8364110 -18.9943500
  HEADING 45.15
  NAVFREQ 0 0
  XPDR 320
  SKINNAME none
  DISPLAYLANDINGPAD 0         ;0=ground base 1=mountain base (eg: phobos) 2= disable
  MAINAIRLOCK 0 0.0000
  PADLIGHT1MODE 0
  PADLIGHT1STATE 0
  UMMUCREW Chem-George_Petropoulos-50-66-92
  UMMUCREW -Vernon_Ready-44-65-91
  UMMUCREW -Stephen_Pye-32-70-62
  UMMUCREW -Joel_Delwasse-40-66-76
  UMMUCREW Vip-Robert_Cummings-54-67-66
  UMMUCREW Tech-Achim_Radmacher-38-68-91
  UMMUCREW Sci-Antonio_Henriquez-27-61-61
  UMMUCREW -Thomas_Boehme-23-69-66
  UMMUCREW Tech-david_Saluman-46-65-71
  UMMUCREW Tech-Sonny_Jakobsen-50-64-74
  UMMUCREW Chem-Sean_OShea-41-62-77
  UMMUCREW Vip-Daniel_Rosh-39-73-83
  UMMUCREW Vip-Adrian_Crownover-53-64-72
  UMMUCREW Sci-Torstein_Soenstaboe-49-72-67
  UMMUCREW -Thomas_Rammacher-31-61-79
END
Upton Village - Wing 2:DGIVPreludeII
  STATUS Landed Moon
  POS -93.8484710 -19.0056600
  HEADING 225.15
  NAVFREQ 0 0
  XPDR 320
  SKINNAME none
  DISPLAYLANDINGPAD 0         ;0=ground base 1=mountain base (eg: phobos) 2= disable
  MAINAIRLOCK 0 0.0000
  PADLIGHT1MODE 0
  PADLIGHT1STATE 0
  UMMUCREW Vip-Stephen_Pye-49-69-86
  UMMUCREW APhy-Joel_Delwasse-25-60-69
  UMMUCREW Sec-Rolf_Feller-54-68-82
  UMMUCREW APhy-Mika_Huovinen-47-61-72
  UMMUCREW -Nicola_Rinaldi-28-72-72
  UMMUCREW -Antonio_Henriquez-43-67-65
  UMMUCREW Sec-Teofilo_Homsany-39-63-78
  UMMUCREW APhy-Ezekiel_Sutton-49-64-83
  UMMUCREW Sci-Kasper_Weinkouff-26-71-89
  UMMUCREW Sec-Raphael_Vincent-58-63-83
  UMMUCREW -Karsten_Hasseler-20-61-80
  UMMUCREW -Caudron_Vincent-33-62-89
END
END_SHIPS

BEGIN_VesselParametersMFD
END

BEGIN_MeshLand_2
  VESSEL=1 
  TERRAIN=1 
  ROTATION=1 
  3RD_LAW=1 
  FRICTION=1 
  GRAVITY=1 
  USEORULEX=1 
  mfd_mode=0 
END
 
Change status to landed on Moon, then delete the RVEL and AROT lines and try that.
 
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