Rocket model loop stability

we are trying to get a stable loop from this tf GthetaM =

          -0.0001017 s^6 + 3.161e-19 s^5 - 0.007922 s^4 + 7.786e-18 s^3 + 0.003973 s^2 + 2.561e-17 s + 1.015e-17
  -----------------------------------------------------------------------------------------------------------------------
  s^8 - 2.998e-15 s^7 - 0.9966 s^6 - 9.695e-16 s^5 + 0.2483 s^4 + 1.227e-15 s^3 + 6.599e-16 s^2 - 7.297e-31 s + 7.393e-32