""" JUICE senario 4. Moon flyby.
I chose first Europa flyby as scenario 4.
The time is 2030-10-05T10:57:19 with closest approach of 1964 km (from center).
"""
import datetime
import irfpy.pep.pep_attitude as patt
import irfpy.juice.jspice as js
#js.furnsh('./160222.mk')
#js.init()
#js.define_juice()
import matplotlib.patches
import matplotlib.dates as mpldates
import numpy as np
import os
js.spice.furnsh('scenario.mk')
n_jp = js.spice.bodn2c('JUPITER')
n_sun = js.spice.bodn2c('SUN')
n_earth = js.spice.bodn2c('EARTH')
n_ganymede = js.spice.bodn2c('GANYMEDE')
n_io = js.spice.bodn2c('IO')
n_europa = js.spice.bodn2c('EUROPA')
n_callisto = js.spice.bodn2c('CALLISTO')
rj = 71492.
re = 1560.8
import irfpy.juice.attitude0 as jatt
import matplotlib.pyplot as plt
def length(v):
return np.sqrt(np.inner(v, v))
def unit_vector(v):
return v / np.sqrt(np.inner(v, v))
def longitude(v):
return np.rad2deg(np.arctan2(v[1], v[0]))
def latitude(v):
vv = unit_vector(v)
return np.rad2deg(np.arcsin(vv[2]))
def get_state(n_target, et, frame, n_origin, unit=rj):
posvel, lt = js.spice.spkez(n_target, et, frame, 'LT+S', n_origin)
return posvel[:3] / unit, posvel[3:]
def main():
fp = open('scenario4.txt', 'w')
print('#datetime mpldates et vx_jse vy_jse vz_jse vx_sc vy_sc vz_sc', file=fp)
print('# Velocity is measured in the spacecraft frame', file=fp)
pathname = 'scenario4'
try:
os.mkdir(pathname)
except:
pass
### 2030-10-05T10:57:19 plus minus 12 hr
t0 = datetime.datetime(2030, 10, 4, 23)
t1 = datetime.datetime(2030, 10, 5, 23)
dt = datetime.timedelta(minutes=10) # Time difference to be confirmed.
t = t0 - dt
# t = t1 - dt
while t <= t1:
t = t + dt
et = js.spice.str2et(t.strftime('%FT%T'))
### Ok, now many object positions can be calculated.
### The variable names are "target"_"frame"_"origin"
### Here SC centered JSE positions
# jupiter_jse_juice, v_jupiter_jse_juice = get_state(n_jp, et, "JSE", -907)
sun_jse_juice, v_sun_jse_juice = get_state(n_sun, et, "JSE", -907)
# earth_jse_juice, __vel = get_state(n_earth, et, "JSE", -907)
# io_jse_juice, __vel = get_state(n_io, et, "JSE", -907)
# europa_jse_juice, __vel = get_state(n_europa, et, "JSE", -907)
# ganymede_jse_juice, __vel = get_state(n_ganymede, et, "JSE", -907)
# callisto_jse_juice, __vel = get_state(n_callisto, et, "JSE", -907)
### Here JSE positions
juice_jse_jupiter, v_juice_jse_jupiter = get_state(-907, et, "JSE", n_jp)
juice_jse_sun, v_juice_jse_sun = get_state(-907, et, "JSE", n_sun)
juice_jse_earth, v_juice_jse_earth = get_state(-907, et, "JSE", n_earth)
juice_jse_europa, v_juice_jse_europa = get_state(-907, et, "JSE", n_europa)
io_jse_jupiter, __vel = get_state(n_io, et, "JSE", n_jp)
europa_jse_jupiter, __vel = get_state(n_europa, et, "JSE", n_jp)
ganymede_jse_jupiter, __vel = get_state(n_ganymede, et, "JSE", n_jp)
callisto_jse_jupiter, __vel = get_state(n_callisto, et, "JSE", n_jp)
sun_jse_jupiter, __vel = get_state(n_sun, et, "JSE", n_jp)
sun_jse_jupiter_unitvector = unit_vector(sun_jse_jupiter)
earth_jse_jupiter, __vel = get_state(n_earth, et, "JSE", n_jp)
earth_jse_jupiter_unitvector = unit_vector(earth_jse_jupiter)
### Here System3 positions (many velocity not used)
juice_sys3_jupiter, v_juice_sys3_jupiter = get_state(-907, et, "IAU_JUPITER", n_jp)
io_sys3_jupiter, __vel = get_state(n_io, et, "IAU_JUPITER", n_jp)
europa_sys3_jupiter, __vel = get_state(n_europa, et, "IAU_JUPITER", n_jp)
ganymede_sys3_jupiter, __vel = get_state(n_ganymede, et, "IAU_JUPITER", n_jp)
callisto_sys3_jupiter, __vel = get_state(n_callisto, et, "IAU_JUPITER", n_jp)
sun_sys3_jupiter, __vel = get_state(n_sun, et, "IAU_JUPITER", n_jp)
sun_sys3_jupiter_unitvector = unit_vector(sun_sys3_jupiter)
earth_sys3_jupiter, __vel = get_state(n_earth, et, "IAU_JUPITER", n_jp)
earth_sys3_jupiter_unitvector = unit_vector(earth_sys3_jupiter)
### Here Europa frame positions (many velocity not used)
juice_europa_europa, v_juice_europa_europa = get_state(-907, et, "IAU_EUROPA", n_europa, unit=re)
io_europa_europa, __vel = get_state(n_io, et, "IAU_EUROPA", n_europa, unit=re)
europa_europa_europa, __vel = get_state(n_europa, et, "IAU_EUROPA", n_europa, unit=re)
ganymede_europa_europa, __vel = get_state(n_ganymede, et, "IAU_EUROPA", n_europa, unit=re)
callisto_europa_europa, __vel = get_state(n_callisto, et, "IAU_EUROPA", n_europa, unit=re)
sun_europa_europa, __vel = get_state(n_sun, et, "IAU_EUROPA", n_europa, unit=re)
sun_europa_europa_unitvector = unit_vector(sun_europa_europa)
earth_europa_europa, __vel = get_state(n_earth, et, "IAU_EUROPA", n_europa, unit=re)
earth_europa_europa_unitvector = unit_vector(earth_europa_europa)
### Conversion matrixes.
cmat_eclip_jse = js.spice.pxform('ECLIPJ2000', 'JSE', et) # Ecliptic -> JSE
cmat_sys3_jse = js.spice.pxform('IAU_JUPITER', 'JSE', et) ### System III to JSE frame conversion matrix
cmat_sys3_europa = js.spice.pxform('IAU_JUPITER', 'IAU_EUROPA', et) # System 3 to Europa fixed.
cmat_jse_europa = js.spice.pxform('JSE', 'IAU_EUROPA', et) # JSE 2 Europa
### Earth's orbital plane.
eclip_norm_vec = cmat_eclip_jse.dot(np.array([0, 0, 1])) # Almost along z by definition.
### Spacecraft frame definition
juice_frame = jatt.get_juice_farflyby(juice_jse_europa, sun_jse_juice)
### Objects in Spacecraft frame
# jupiter_sc_juice = juice_frame.convert_to_nsc(jupiter_jse_juice)
# sun_sc_juice = juice_frame.convert_to_nsc(sun_jse_juice)
# earth_sc_juice = juice_frame.convert_to_nsc(earth_jse_juice)
# io_sc_juice = juice_frame.convert_to_nsc(io_jse_juice)
# europa_sc_juice = juice_frame.convert_to_nsc(europa_jse_juice)
# ganymede_sc_juice = juice_frame.convert_to_nsc(ganymede_jse_juice)
# callisto_sc_juice = juice_frame.convert_to_nsc(callisto_jse_juice)
fig = plt.figure(figsize=(12, 12))
axes={}
### Orbit plot (xy in JSE)
ax = fig.add_axes([0.1, 0.4, 0.35, 0.35])
axes['orbit_jse_xy'] = ax
# Spacecraft position in JSE
ax.plot([juice_jse_jupiter[0]], [juice_jse_jupiter[1]], 'ko')
# SC->JSE conversion, plot
armlen = 3
vec_xaxis_jse = juice_frame.convert_to_ref([1, 0 ,0])
vec_yaxis_jse = juice_frame.convert_to_ref([0, 1 ,0])
vec_zaxis_jse = juice_frame.convert_to_ref([0, 0 ,1])
ax.plot(juice_jse_jupiter[0] + [0, vec_xaxis_jse[0] * armlen],
juice_jse_jupiter[1] + [0, vec_xaxis_jse[1] * armlen],
'r')
ax.text(juice_jse_jupiter[0] + vec_xaxis_jse[0] * armlen,
juice_jse_jupiter[1] + vec_xaxis_jse[1] * armlen,
'x', color='r')
ax.plot(juice_jse_jupiter[0] + [0, vec_yaxis_jse[0] * armlen],
juice_jse_jupiter[1] + [0, vec_yaxis_jse[1] * armlen],
'g')
ax.text(juice_jse_jupiter[0] + vec_yaxis_jse[0] * armlen,
juice_jse_jupiter[1] + vec_yaxis_jse[1] * armlen,
'y', color='g')
ax.plot(juice_jse_jupiter[0] + [0, vec_zaxis_jse[0] * armlen],
juice_jse_jupiter[1] + [0, vec_zaxis_jse[1] * armlen],
'b')
ax.text(juice_jse_jupiter[0] + vec_zaxis_jse[0] * armlen,
juice_jse_jupiter[1] + vec_zaxis_jse[1] * armlen,
'z', color='b')
# Decoration
ax.plot([0, 0], [-100, 100], 'k:')
ax.plot([-100, 100], [0, 0], 'k:')
ax.plot([-100, 100], [100, -100], 'k:')
ax.plot([-100, 100], [-100, 100], 'k:')
x = np.cos(np.linspace(0, np.pi * 2, 100))
y = np.sin(np.linspace(0, np.pi * 2, 100))
for r in np.arange(5, 100, 5): ax.plot(r * x, r * y, 'k:')
ax.plot(x, y, 'k')
ax.set_xlim(-30, 30)
ax.set_ylim(-30, 30)
ax.set_xlabel('X [JSE]')
ax.set_ylabel('Y [JSE]')
ax.set_title('{:%FT%T}'.format(t))
ax.set_aspect('equal')
ax.text(io_jse_jupiter[0], io_jse_jupiter[1], 'I', color='g', ha='center', va='center')
ax.text(europa_jse_jupiter[0], europa_jse_jupiter[1], 'E', color='g', ha='center', va='center')
ax.text(ganymede_jse_jupiter[0], ganymede_jse_jupiter[1], 'G', color='g', ha='center', va='center')
ax.text(callisto_jse_jupiter[0], callisto_jse_jupiter[1], 'C', color='g', ha='center', va='center')
# Sun,earth direction
ax.plot([0, sun_jse_jupiter_unitvector[0] * 10],
[0, sun_jse_jupiter_unitvector[1] * 10],
'r-')
ax.text(sun_jse_jupiter_unitvector[0] * 10, sun_jse_jupiter_unitvector[1] * 10,
'S', color='r')
ax.plot([0, earth_jse_jupiter_unitvector[0] * 10],
[0, earth_jse_jupiter_unitvector[1] * 10],
'b-')
ax.text(earth_jse_jupiter_unitvector[0] * 10, earth_jse_jupiter_unitvector[1]* 10,
'E', color='b')
### Orbit plot (xz in JSE)
ax = fig.add_axes([0.1, 0.78, 0.35, 0.20])
axes['orbit_jse_xz'] = ax
# ax = patt.axis_configuration_xz(juice_frame, axis=ax)
# Spacecraft position in JSE
ax.plot([juice_jse_jupiter[0]], [juice_jse_jupiter[2]], 'ko')
# SC->JSE conversion, plot
ax.plot(juice_jse_jupiter[0] + [0, vec_xaxis_jse[0] * armlen],
juice_jse_jupiter[2] + [0, vec_xaxis_jse[2] * armlen],
'r')
ax.text(juice_jse_jupiter[0] + vec_xaxis_jse[0] * armlen,
juice_jse_jupiter[2] + vec_xaxis_jse[2] * armlen,
'x', color='r')
ax.plot(juice_jse_jupiter[0] + [0, vec_yaxis_jse[0] * armlen],
juice_jse_jupiter[2] + [0, vec_yaxis_jse[2] * armlen],
'g')
ax.text(juice_jse_jupiter[0] + vec_yaxis_jse[0] * armlen,
juice_jse_jupiter[2] + vec_yaxis_jse[2] * armlen,
'y', color='g')
ax.plot(juice_jse_jupiter[0] + [0, vec_zaxis_jse[0] * armlen],
juice_jse_jupiter[2] + [0, vec_zaxis_jse[2] * armlen],
'b')
ax.text(juice_jse_jupiter[0] + vec_zaxis_jse[0] * armlen,
juice_jse_jupiter[2] + vec_zaxis_jse[2] * armlen,
'z', color='b')
# Decoration
ax.plot([0, 0], [-1.1, 1.1], 'k-')
ax.plot([-100, 100], [0, 0], 'k:')
x = np.cos(np.linspace(0, np.pi * 2, 100))
y = np.sin(np.linspace(0, np.pi * 2, 100))
ax.plot(x, y, 'k')
ax.set_xlim(-30, 30)
ax.set_ylim(-10, 10)
ax.set_xlabel('X [JSE]')
ax.set_ylabel('Z [JSE]')
ax.set_title('{:%FT%T}'.format(t))
ax.set_aspect('equal')
ax.text(io_jse_jupiter[0], io_jse_jupiter[2], 'I', color='g', ha='center', va='center')
ax.text(europa_jse_jupiter[0], europa_jse_jupiter[2], 'E', color='g', ha='center', va='center')
ax.text(ganymede_jse_jupiter[0], ganymede_jse_jupiter[2], 'G', color='g', ha='center', va='center')
ax.text(callisto_jse_jupiter[0], callisto_jse_jupiter[2], 'C', color='g', ha='center', va='center')
### Sun direction
ax.plot([0, sun_jse_jupiter_unitvector[0] * 10],
[0, sun_jse_jupiter_unitvector[2] * 10],
'r-')
ax.text(sun_jse_jupiter_unitvector[0] * 10, sun_jse_jupiter_unitvector[2] * 10,
'S', color='r')
ax.plot([0, earth_jse_jupiter_unitvector[0] * 10],
[0, earth_jse_jupiter_unitvector[2] * 10],
'b-')
ax.text(earth_jse_jupiter_unitvector[0] * 10, earth_jse_jupiter_unitvector[2] * 10,
'E', color='b')
### S/C at Europa frame
### Orbit plot (xy)
ax = fig.add_axes([0.5, 0.4, 0.35, 0.35])
axes['orbit_moon_xy'] = ax
ax.plot([juice_europa_europa[0]], [juice_europa_europa[1]], 'ko')
ax.plot([0, 0], [-100, 100], 'k:')
ax.plot([-100, 100], [0, 0], 'k:')
ax.plot([-100, 100], [100, -100], 'k:')
ax.plot([-100, 100], [-100, 100], 'k:')
x = np.cos(np.linspace(0, np.pi * 2, 100))
y = np.sin(np.linspace(0, np.pi * 2, 100))
for r in np.arange(5, 100, 10): ax.plot(r * x, r * y, 'k:')
ax.plot(x, y, 'k')
ax.set_xlim(-100, 100)
ax.set_ylim(-100, 100)
ax.set_xlabel('X [EUROPA]')
ax.set_ylabel('Y [EUROPA]')
# ax.set_xscale('symlog', linthreshx=30, linscalex=2)
# ax.set_yscale('symlog', linthreshy=30, linscaley=2)
# import matplotlib.patches as mplp
# bbox = mplp.Rectangle((-30, -30), 60, 60, facecolor='none', edgecolor='k', linestyle='-')
# ax.add_patch(bbox)
if np.abs(juice_europa_europa[0]) < 100 and np.abs(juice_europa_europa[1]) < 100:
armlen = 15
vec_xaxis_europa = cmat_jse_europa.dot(vec_xaxis_jse)
vec_yaxis_europa = cmat_jse_europa.dot(vec_yaxis_jse)
vec_zaxis_europa = cmat_jse_europa.dot(vec_zaxis_jse)
ax.plot(juice_europa_europa[0] + [0, vec_xaxis_europa[0] * armlen],
juice_europa_europa[1] + [0, vec_xaxis_europa[1] * armlen],
'r')
ax.text(juice_europa_europa[0] + vec_xaxis_europa[0] * armlen,
juice_europa_europa[1] + vec_xaxis_europa[1] * armlen,
'x', color='r')
ax.plot(juice_europa_europa[0] + [0, vec_yaxis_europa[0] * armlen],
juice_europa_europa[1] + [0, vec_yaxis_europa[1] * armlen],
'g')
ax.text(juice_europa_europa[0] + vec_yaxis_europa[0] * armlen,
juice_europa_europa[1] + vec_yaxis_europa[1] * armlen,
'y', color='g')
ax.plot(juice_europa_europa[0] + [0, vec_zaxis_europa[0] * armlen],
juice_europa_europa[1] + [0, vec_zaxis_europa[1] * armlen],
'b')
ax.text(juice_europa_europa[0] + vec_zaxis_europa[0] * armlen,
juice_europa_europa[1] + vec_zaxis_europa[1] * armlen,
'z', color='b')
ax.set_title('{:%FT%T}'.format(t))
# ax.text(io_europa_europa[0], io_europa_europa[1], 'I', color='g')
# ax.text(europa_europa_europa[0], europa_europa_europa[1], 'E', color='g')
# ax.text(ganymede_europa_europa[0], ganymede_europa_europa[1], 'G', color='g')
# ax.text(callisto_europa_europa[0], callisto_europa_europa[1], 'C', color='g')
# Sun,earth direction
ax.plot([0, sun_europa_europa_unitvector[0] * 10],
[0, sun_europa_europa_unitvector[1] * 10],
'r-')
ax.text(sun_europa_europa_unitvector[0] * 10, sun_europa_europa_unitvector[1] * 10,
'S', color='r')
ax.plot([0, earth_europa_europa_unitvector[0] * 10],
[0, earth_europa_europa_unitvector[1] * 10],
'b-')
ax.text(earth_europa_europa_unitvector[0] * 10, earth_europa_europa_unitvector[1] * 10,
'E', color='b')
### Plot of SC in x-z plane.
ax = fig.add_axes([0.5, 0.78, 0.35, 0.20])
axes['orbit_moon_xz'] = ax
ax.plot([juice_europa_europa[0]], [juice_europa_europa[2]], 'ko')
ax.plot([0, 0], [-1.1, 1.1], 'k-')
ax.plot([-100, 100], [0, 0], 'k:')
x = np.cos(np.linspace(0, np.pi * 2, 100))
y = np.sin(np.linspace(0, np.pi * 2, 100))
ax.plot(x, y, 'k')
ax.set_xlim(-100, 100)
ax.set_ylim(-100 / 3., 100 / 3.)
ax.set_xlabel('X [EUROPA]')
ax.set_ylabel('Z [EUROPA]')
ax.set_aspect('equal')
if np.abs(juice_europa_europa[0]) < 100 and np.abs(juice_europa_europa[2]) < 33.33:
armlen = 15
vec_xaxis_europa = cmat_jse_europa.dot(vec_xaxis_jse)
vec_yaxis_europa = cmat_jse_europa.dot(vec_yaxis_jse)
vec_zaxis_europa = cmat_jse_europa.dot(vec_zaxis_jse)
ax.plot(juice_europa_europa[0] + [0, vec_xaxis_europa[0] * armlen],
juice_europa_europa[2] + [0, vec_xaxis_europa[2] * armlen],
'r')
ax.text(juice_europa_europa[0] + vec_xaxis_europa[0] * armlen,
juice_europa_europa[2] + vec_xaxis_europa[2] * armlen,
'x', color='r')
ax.plot(juice_europa_europa[0] + [0, vec_yaxis_europa[0] * armlen],
juice_europa_europa[2] + [0, vec_yaxis_europa[2] * armlen],
'g')
ax.text(juice_europa_europa[0] + vec_yaxis_europa[0] * armlen,
juice_europa_europa[2] + vec_yaxis_europa[2] * armlen,
'y', color='g')
ax.plot(juice_europa_europa[0] + [0, vec_zaxis_europa[0] * armlen],
juice_europa_europa[2] + [0, vec_zaxis_europa[2] * armlen],
'b')
ax.text(juice_europa_europa[0] + vec_zaxis_europa[0] * armlen,
juice_europa_europa[2] + vec_zaxis_europa[2] * armlen,
'z', color='b')
### Other objects
# ax.text(io_europa_europa[0], io_europa_europa[2], 'I', color='g')
# ax.text(europa_europa_europa[0], europa_europa_europa[2], 'E', color='g')
# ax.text(ganymede_europa_europa[0], ganymede_europa_europa[2], 'G', color='g')
# ax.text(callisto_europa_europa[0], callisto_europa_europa[2], 'C', color='g')
# Sun,earth direction
ax.plot([0, sun_europa_europa_unitvector[0] * 10],
[0, sun_europa_europa_unitvector[2] * 10],
'r-')
ax.text(sun_europa_europa_unitvector[0] * 10, sun_europa_europa_unitvector[2] * 10,
'S', color='r')
ax.plot([0, earth_europa_europa_unitvector[0] * 10],
[0, earth_europa_europa_unitvector[2] * 10],
'b-')
ax.text(earth_europa_europa_unitvector[0] * 10, earth_europa_europa_unitvector[2] * 10,
'E', color='b')
### Calculate the corotation flow.
# Assume the corotation flow is axisymmetric flow wrt the rotation axis (System 3)
# The flow vector is perpendicular to the position vector in x-y plane, without z component.
speed_solid_corotation_sys3 = length(juice_sys3_jupiter) * rj * 2 * np.pi / 36000. # 10 hour per rotation assumed
vel_solid_corotation_sys3 = [-juice_sys3_jupiter[1], juice_sys3_jupiter[0], 0]
vel_solid_corotation_sys3_unitvector = unit_vector(vel_solid_corotation_sys3)
vel_solid_corotation_sys3 = vel_solid_corotation_sys3_unitvector * speed_solid_corotation_sys3
print('Corotation/1st order', vel_solid_corotation_sys3, speed_solid_corotation_sys3)
### Geometric conversion from SystemIII to JSE. (Velocity measured at spacecraft -> geometric/position conversion,
### not velocity conversion)
vel_solid_corotation_jse = cmat_sys3_jse.dot(vel_solid_corotation_sys3)
### Plasma flow at the spacecraft. Expressed in JSE frame.
vel_solid_corotation_sys3 = vel_solid_corotation_jse - v_juice_jse_jupiter
### Plasma flow at the spacecraft. Convert it to SC frame.
vel_solid_corotation_sc = juice_frame.convert_to_nsc(vel_solid_corotation_sys3)
print('{0:%FT%T} {4:.5f} {1:.3f} {2[0]:.2f} {2[1]:.2f} {2[2]:.2f} {3[0]:.2f} {3[1]:.2f} {3[2]:.2f}'.format(
t, et, vel_solid_corotation_sys3, vel_solid_corotation_sc, mpldates.date2num(t)), file=fp)
print('{0:%FT%T} {4:.5f} {1:.3f} {2[0]:.2f} {2[1]:.2f} {2[2]:.2f} {3[0]:.2f} {3[1]:.2f} {3[2]:.2f}'.format(
t, et, vel_solid_corotation_sys3, vel_solid_corotation_sc, mpldates.date2num(t)))
### Viewing direction axis
ax = fig.add_axes([0.1, 0.08, 0.35, 0.20])
## Boundary of the viewing direction
import fovplot
fovplot.frame_plot_limit(ax=ax, alpha=0.1)
ax.text(0, 0, 'Tilt=0', color='r')
fovplot.frame_plot_limit(ax=ax, tilt=15, alpha=0.1)
ax.text(0, 15, 'Tilt=15', color='r')
fovplot.frame_plot_limit(ax=ax, tilt=30, alpha=0.1)
ax.text(0, 30, 'Tilt=30', color='r')
fovplot.frame_plot_limit(ax=ax, tilt=45, alpha=0.1)
ax.text(0, 45, 'Tilt=45', color='r')
## Direction of the corotation flow in SC
looking_vco_long = longitude(-vel_solid_corotation_sc)
looking_vco_lat = latitude(-vel_solid_corotation_sc)
ax.plot([looking_vco_long], [looking_vco_lat], 'bo')
ax.text(looking_vco_long, looking_vco_lat, 'Corot', color='b')
## Galileans / Earth / Sun
for num, nam, clr in zip((n_jp, n_sun, n_earth, n_io, n_europa, n_ganymede, n_callisto),
('Jupiter', 'Sun', 'Earth', 'Io', 'Europa', 'Ganymede', 'Callisto'),
('g', 'r', 'b', 'g', 'g', 'g', 'g')):
looking_object_jse, __vel = get_state(num, et, 'JSE', -907)
looking_object_sc = juice_frame.convert_to_nsc(looking_object_jse)
looking_object_long = longitude(looking_object_sc)
looking_object_lat = latitude(looking_object_sc)
if np.abs(looking_object_lat) > 89.5:
looking_object_long = 0.
ax.plot([looking_object_long], [looking_object_lat], clr + 'o')
ax.text(looking_object_long, looking_object_lat, nam, color=clr)
## Europa horizon
distance = length(juice_europa_europa) # Europa-S/C in re.
angle = np.rad2deg(np.arcsin(1 / distance)) # Europa angle
ax.axhline(90 - angle, color='g')
print(angle)
plt.gcf().savefig(os.path.join(pathname, 'scenario4_{:d}.png'.format(int(et))))
plt.close('all')
fp.flush()
if __name__ == '__main__':
main()