Skylab 1973 rebuild

[gattispilot]

So what should I set the CMG to? I wonder if there is away for the CMg to be always adjusting?

 

[BrianJ]

Hi @gattispilot
you were asking about pointing Skylab +Y at the Sun.
A couple of ideas for you....
1. Does CMG have a "Kill Rot" or "Fixed Attitude" mode? If so, then set attitude as required (nice idea using PursuitMFD to get the P/Y/R angles) and hit the Kill Rot mode.

2. Following bit of code will put the +Y axis pointed at the Sun, and +Z axis in orbit plane.
Call it each frame to keep vessel locked in place (if required).

void MyVesssel::DoSunPointing()
{
    VESSELSTATUS vs;
    GetStatus(vs);

    VECTOR3 glob_pos_unit = _V(0,0,0);
    GetGlobalPos(glob_pos_unit);
    normalise(glob_pos_unit);
    glob_pos_unit = -glob_pos_unit;


    VECTOR3 vel_unit = _V(0,0,0);
    GetRelativeVel(GetGravityRef(), vel_unit);
    normalise(vel_unit);

    VECTOR3 pos_unit = _V(0,0,0);
    GetRelativePos(GetGravityRef(), pos_unit);
    normalise(pos_unit);

    VECTOR3 orb_normal_unit = crossp(pos_unit, vel_unit);
    normalise(orb_normal_unit);

    VECTOR3 ves_z_axis_unit = crossp(orb_normal_unit, glob_pos_unit);
    normalise(ves_z_axis_unit);

    VECTOR3 ves_x_axis_unit = crossp(glob_pos_unit, ves_z_axis_unit );
    normalise(ves_x_axis_unit);


    VECTOR3 xright = ves_x_axis_unit;
    VECTOR3 yup = glob_pos_unit;
    VECTOR3 zforward = ves_z_axis_unit;


double gamma = atan2( xright.x, yup.x);
double beta = -1*(asin(zforward.x));
double alpha = atan2(zforward.y, zforward.z);

vs.arot = _V(alpha, beta, (PI/2)-gamma);
vs.vrot = _V(0,0,0);

DefSetState(&vs);

}

Cheers,
Brian

 

[gattispilot]

Thanks
yes if the ISS_HD does Skylab does
Keyboard commands:
1 = CMG Free Drift
2 = CMG Zero Angular
3 = CMG Attitude Keeping
7 = Enter TGT Roll
8 = Enter TGT Pitch
9 = Enter TGT Yaw

But I think the Attitude keeping just keeps it had what you set? Rather follow the sun?
In the 2nd image is is set at hold or Zero angular
and the pitch should +90 of the mfd, right?

 

[gattispilot]

Here is the CMG at CMG Zero Angular not sure if the data for the cmg is correct per the the mfd?
I would thing the skylab would be facing to the sun ?

 

[gattispilot]

@BrianJ
I tried your sun pointing. And it pulled Skylab into the earth and the spun here wildly

 

[gattispilot]

So Tried SKYLABHD in NASSP.
Still not sure on the Sun Aiming. So open Pursuit MFD set the target as the SUN. and then set the CMG to match the values, right. Tell the CMG to adjust to those values. And then hold?