code: def _get_satellite_unit_vector_z(attitude, orbit):
      v1950 = _get_satellite_z_axis_1950(
          attitude.angle_between_sat_spin_and_z_axis,
          attitude.angle_between_sat_spin_and_yz_plane,
      )
      vcorr = _correct_nutation_precession(
          v1950, orbit.nutation_precession
      )
      return _rotate_to_greenwich(
          vcorr, orbit.angles.greenwich_sidereal_time
      )
  
imports: from collections import namedtuple
  import dask.array
  import numba
  import numpy
  from satpy.utils import get_legacy_chunk_size
label_desc: Use image node_id 13 for calling a global function with example usage: _get_satellite_unit_vector_z(attitude, orbit) and returns: _rotate_to_greenwich