Example - 44 - Ice Giant Pre-Decadal - Neptune Probe (Concept)

from AMAT.planet import Planet
from AMAT.vehicle import Vehicle

import numpy as np
import matplotlib.pyplot as plt

This notebook simulates the atmospheric entry of the Neptune entry probe described in Sec. A.5.3 of the Ice Giants Pre-Decadal Mission Study. https://www.lpi.usra.edu/icegiants/mission_study/Full-Report.pdf

# Set up the planet and atmosphere model.
planet=Planet("NEPTUNE")
planet.h_skip = 1000.0E3
planet.h_trap = -100.0E3
planet.loadAtmosphereModel('../atmdata/Neptune/neptune-gram-avg.dat', 0 , 7 ,6, 5 , heightInKmFlag=True)

# Set up the vehicle
vehicle1=Vehicle('igpd-neptune', 325.0, 205.0, 0.0, np.pi*1.2**2.0*0.25, 0.0, 0.20, planet)

# Set up entry parameters
vehicle1.setInitialState(1000.0,0.0,0.0,25.73,0.0,-20.0,0.0,0.0)

# Set up solver
vehicle1.setSolverParams(1E-6)

# Propogate vehicle entry trajectory
vehicle1.propogateEntry (120.0*60.0,0.1,0.0)

# import rcParams to set figure font type
from matplotlib import rcParams

fig = plt.figure(figsize=(12,8))
plt.rc('font',family='Times New Roman')
params = {'mathtext.default': 'regular' }
plt.rcParams.update(params)

plt.subplot(2, 2, 1)
plt.plot(vehicle1.v_kmsc, vehicle1.h_kmc, 'k-', linewidth=2.0)

plt.xlabel('Speed, km/s',fontsize=14)
plt.ylabel('Altitude, km', fontsize=14)
ax=plt.gca()
ax.tick_params(direction='in')
ax.yaxis.set_ticks_position('both')
ax.xaxis.set_ticks_position('both')
ax.tick_params(axis='x',labelsize=14)
ax.tick_params(axis='y',labelsize=14)

plt.subplot(2, 2, 2)
plt.plot(vehicle1.acc_net_g, vehicle1.h_kmc, 'b-', linewidth=2.0)
plt.xlabel('Deceleration, Earth g',fontsize=14)
plt.ylabel('Altitude, km', fontsize=14)
ax=plt.gca()
ax.tick_params(direction='in')
ax.yaxis.set_ticks_position('both')
ax.xaxis.set_ticks_position('both')
ax.tick_params(axis='x',labelsize=14)
ax.tick_params(axis='y',labelsize=14)

plt.subplot(2, 2, 3)
plt.plot(vehicle1.q_stag_total, vehicle1.h_kmc,'r-', linewidth=2.0)
plt.xlabel('Stagnation point heat-rate, '+r'$W/cm^2$',fontsize=14)
plt.ylabel('Altitude, km', fontsize=14)
ax=plt.gca()
ax.tick_params(direction='in')
ax.yaxis.set_ticks_position('both')
ax.xaxis.set_ticks_position('both')
ax.tick_params(axis='x',labelsize=14)
ax.tick_params(axis='y',labelsize=14)


plt.subplot(2, 2, 4)
plt.plot(vehicle1.heatload/1.0E3, vehicle1.h_kmc, 'm-', linewidth=2.0)
plt.xlabel('Stagnation point heat-load, '+r'$kJ/cm^2$',fontsize=14)
plt.ylabel('Altitude, km', fontsize=14)
ax=plt.gca()
ax.tick_params(direction='in')
ax.yaxis.set_ticks_position('both')
ax.xaxis.set_ticks_position('both')
ax.tick_params(axis='x',labelsize=14)
ax.tick_params(axis='y',labelsize=14)

plt.savefig('../plots/igpd-neptune.png',bbox_inches='tight')
plt.savefig('../plots/igpd-neptune.pdf', dpi=300,bbox_inches='tight')
plt.savefig('../plots/igpd-neptune.eps', dpi=300,bbox_inches='tight')

plt.show()

Discrepancies are attributed to initial state being not properly converted to planet-relative frame, and different heating relations used in the studies.