Example - 65 - Probe-Orbiter Deflection Maneuver

In this example, we illustrate the calculation of the orbiter divert maneuver delta-V after probe release.

import numpy as np
from AMAT.maneuver import ProbeOrbiterDeflection

The probe will enter near equator, prograde. The orbiter will target a 4000 km periapsis altitude, near equatorial retrograde orbit. The deflection manuever is performed 60 days before probe entry, at a distance of 4225 times the radius of Neptune.

deflection = ProbeOrbiterDeflection(arrivalPlanet="NEPTUNE",
                                    v_inf_vec_icrf_kms=np.array([17.78952518,  8.62038536,  3.15801163]),
                                    rp_probe=(24622+400)*1e3,  psi_probe=3*np.pi/2, h_EI_probe=1000e3,
                                    rp_space=(24622+4000)*1e3, psi_space=np.pi/2,

Compute the orbit divert maneuver delta-V

print("Divert manuever DV: "+str(deflection.dv_maneuver_vec)+ " m/s")
Divert manuever DV: [-1.15867678e+00  1.55142771e+01 -9.20109868e-04] m/s
print("Divert manuever DV magnitude: "+str(round(deflection.dv_maneuver_mag,3))+ " m/s")
Divert manuever DV magnitude: 15.557 m/s
print("TOF from probe release to atm. entry interface: "+str(round(deflection.TOF_probe,6))+ " days")
print("TOF from probe release to orbiter periapsis   : "+str(round(deflection.TOF_space,6))+ " days")
TOF from probe release to atm. entry interface: 60.070866 days
TOF from probe release to orbiter periapsis   : 60.071683 days

Run python example-65-probe-orbiter-deflection-viz.py from your virtual env terminal to generate the figure below showing the geometry of the two approach trajectories.

from IPython.display import Image
Image(filename="../plots/example-65-probe-orbiter-deflection.png", width=800)