def test_path_can_be_calculated_with_a_maneuver(self):
"""
This method is intended to be a direct translation of the
test in testpath.cc of the same name.
"""
body = PyBody(gm=const.G * 1.98891691172467e30, r=10)
system = PySystem(root=body)
r = PyVector(617244712358.0, -431694791368.0, -12036457087.0)
v = PyVector(7320.0, 11329.0, -0211.0)
path_ = path.PyFlightPath(system, r, v, 0)
half_orbit_t = 374942509.78053558 / 2
performance = path.PyPerformanceData(3000, 20000) # ve, thrust
path_.add(
path.PyManeuver(path.PyManeuver.Types.Prograde, 2000, performance,
150, half_orbit_t))
# predict orbit of 1/2 period from t0.
prediction1 = path_.predict(half_orbit_t)
# This test doesn't try to determine a precise position, just that
# the calculation can complete, and results in a changed orbit.
position1 = prediction1.r
self.assertAlmostEqual(-719081127257.4052, position1.x, 0)
self.assertAlmostEqual(364854624247.8101, position1.y, 0)
self.assertAlmostEqual(14595231066.51168, position1.z, 0)
# predict orbit of 3/2 period from t0.
# Orbit should have changed notably
prediction2 = path_.predict(374942509.78053558 * 3.0 / 2.0)
position2 = prediction2.r
self.assertNotAlmostEqual(-712305324741.15112, position2.x, 0)
self.assertNotAlmostEqual(365151451881.22858, position2.y, 0)
self.assertNotAlmostEqual(14442203602.998617, position2.z, 0)
def test_path_maneuver_increases_velocity(self):
"""
This method is intended to be a direct translation of the
test in testpath.cc of the same name.
"""
body = PyBody(gm=const.G * 1.98891691172467e30, r=10)
system = PySystem(root=body)
r = PyVector(617244712358.0, -431694791368.0, -12036457087.0)
v = PyVector(7320.0, 11329.0, -0211.0)
path_ = path.PyFlightPath(system, r, v, 0)
half_orbit_t = 374942509.78053558 / 2
performance = path.PyPerformanceData(3000, 20000) # ve, thrust
dv = 2000
maneuver = path.PyManeuver(path.PyManeuver.Types.Prograde, dv,
performance, 150, half_orbit_t)
path_.add(maneuver)
# Predict orbit of 1/2 period from t0.
prediction0 = path_.predict(half_orbit_t)
# Predict orbit at end of burn
prediction1 = path_.predict(maneuver.t1)
# This test doesn't try to determine a precise velocity, just that
# it has increased a roughly expected amount.
v0 = prediction0.v
v1 = prediction1.v
self.assertAlmostEqual(v1.norm, v0.norm + dv, -1) # within ~10
def test_r_and_v_between_segment_groups_match(self):
body = PyBody(gm=const.G * 1.98891691172467e30, r=10)
system = PySystem(root=body)
r = PyVector(617244712358.0, -431694791368.0, -12036457087.0)
v = PyVector(7320.0, 11329.0, -0211.0)
path_ = path.PyFlightPath(system, r, v, 0)
period0 = 374942509.78053558
performance = path.PyPerformanceData(3000, 200) # ve, thrust
burn_start_t = period0 / 2
maneuver = path.PyManeuver(
path.PyManeuver.Types.Prograde, # Maneuver Type
2, # DV
performance,
150.0, # m0
burn_start_t) # t0
path_.add(maneuver)
seg0_end_data = path_.predict(burn_start_t - 0.001)
seg1_start_data = path_.predict(burn_start_t)
# Roundabout check to make sure both predictions were different
self.assertNotEqual(seg0_end_data.v.x, seg1_start_data.v.x)
# Check that velocities nearly match
self.assertAlmostEqual(seg0_end_data.v.x, seg1_start_data.v.x, 6)
self.assertAlmostEqual(seg0_end_data.v.y, seg1_start_data.v.y, 6)
self.assertAlmostEqual(seg0_end_data.v.z, seg1_start_data.v.z, 6)
def burn_plot() -> None:
body = PyBody(gm=const.G * 1.98891691172467e30, r=10)
system = PySystem(root=body)
r = PyVector(617_244_712_358.0, -431_694_791_368.0, -12_036_457_087.0)
v = PyVector(7320.0, 11329.0, -0211.0)
path_ = path.PyFlightPath(system, r, v, 0)
period0 = 374942509.78053558
performance = path.PyPerformanceData(3000, 2000) # ve, thrust
burn_start_t = 2
maneuver = path.PyManeuver(path.PyManeuver.Types.Prograde, 10, performance,
150, burn_start_t)
path_.add(maneuver)
maneuver = path.PyManeuver(path.PyManeuver.Types.Prograde, 10, performance,
150, burn_start_t + 2)
path_.add(maneuver)
# Get Data to plot
t_pts = []
v_pts = []
apo_pts = []
a_pts = []
t0 = maneuver.t0 - 3
tf = maneuver.t1 + 3
plot_duration = tf - t0
for i in range(N_POINTS):
t = plot_duration / N_POINTS * i + t0
t_pts.append(t - maneuver.t0) # Time relative to burn t0
orbit_data = path_.predict_orbit(t)
v_pts.append(orbit_data.orbit.velocity.norm)
apo_pts.append(orbit_data.orbit.apoapsis)
a_pts.append(orbit_data.orbit.semi_major_axis)
# Plot
gs = gridspec.GridSpec(2, 2)
plt.subplots_adjust(hspace=0.5, wspace=0.35)
# Velocity plot
plt.subplot(gs[0, 0])
plt.title('Velocity')
plt.plot(t_pts, v_pts, 'r-')
# Apoapsis plot
plt.subplot(gs[1, 0])
plt.title('Apoapsis')
plt.plot(t_pts, apo_pts)
# Semi major axis plot
plt.subplot(gs[0, 1])
plt.title('Semi Major Axis')
plt.plot(t_pts, a_pts)
plt.show()
def test_orbit_data_can_be_calculated_at_time_0(self):
body = PyBody(gm=const.G * 1.98891691172467e30, r=10)
system = PySystem(root=body)
r = PyVector(-719081127257.4052, -364854624247.8101,
-14595231066.51168)
v = PyVector(7320.0, 11329.0, -0211.0)
path_ = path.PyFlightPath(system, r, v, 0)
prediction: path.PyOrbitData = path_.predict_orbit(0)
position: PyVector = prediction.orbit.position
self.assertAlmostEqual(-719081127257.4052, position.x, 0)
self.assertAlmostEqual(-364854624247.8101, position.y, 0)
self.assertAlmostEqual(-14595231066.51168, position.z, 0)
self.assertEqual(body.id, prediction.body.id)
def test_orbit_data_can_be_calculated_at_arbitrary_time(self):
body = PyBody(gm=const.G * 1.98891691172467e30, r=10)
system = PySystem(root=body)
r = PyVector(-719081127257.4052, -364854624247.8101,
-14595231066.51168)
v = PyVector(7320.0, 11329.0, -0211.0)
path_ = path.PyFlightPath(system, r, v, 0)
prediction: path.PyOrbitData = \
path_.predict_orbit(374942509.78053558 / 2)
position: PyVector = prediction.orbit.position
self.assertAlmostEqual(-483167275930.97107, position.x, 0)
self.assertAlmostEqual(-1432791663675.9163, position.y, 0)
self.assertAlmostEqual(46273154729.87547, position.z, 0)
self.assertEqual(body.id, prediction.body.id)
def test_path_with_no_maneuvers_can_be_calculated(self):
"""
This method is intended to be a direct translation of the
test in testpath.cc of the same name.
"""
body = PyBody(gm=const.G * 1.98891691172467e30, r=10)
system = PySystem(root=body)
r = PyVector(617244712358.0, -431694791368.0, -12036457087.0)
v = PyVector(7320.0, 11329.0, -0211.0)
path_ = path.PyFlightPath(system, r, v, 0)
prediction: path.PyKinematicData = path_.predict(374942509.78053558 /
2)
position: PyVector = prediction.r
self.assertAlmostEqual(-719081127257.4052, position.x, 0)
self.assertAlmostEqual(364854624247.8101, position.y, 0)
self.assertAlmostEqual(14595231066.51168, position.z, 0)
def simple_hyperbolic_path() -> None:
body = PyBody(gm=const.G * 1.98891691172467e30, r=10)
system = PySystem(root=body)
r = PyVector(-719081127257.4052, -364854624247.8101, -14595231066.51168)
v = PyVector(7320.0, 21000.0, -0211.0)
path_ = path.PyFlightPath(system, r, v, 0)
# Get points to plot
x_pts = []
y_pts = []
z_pts = []
for i in range(N_POINTS):
t = 374942509.78053558 * 2 / N_POINTS * i
predicted: path.PyKinematicData = path_.predict(t)
x_pts.append(predicted.r.x)
y_pts.append(predicted.r.y)
z_pts.append(predicted.r.z)
# Plot
plt.figure(1)
gs = gridspec.GridSpec(1, 2)
plt.subplots_adjust(hspace=0.5, wspace=0.35)
plt.subplot(gs[0, 0])
plt.plot(0, 0, 'ro') # Body position.
plt.plot(x_pts, y_pts, 'r-') # line
plt.plot(r.x, r.y, 'ro') # current pos
plt.plot(x_pts[0], y_pts[0], 'yo')
plt.axis('equal')
plt.subplot(gs[0, 1])
plt.plot(0, 0, 'ro') # Body position.
plt.plot(x_pts, z_pts, 'r-') # line
plt.plot(r.x, r.z, 'ro') # current pos
plt.plot(x_pts[0], z_pts[0], 'yo')
plt.axis('equal')
plt.show()
def position_plot() -> None:
body = PyBody(gm=const.G * 5.972e24, r=10)
system = PySystem(root=body)
r = PyVector(617_244_712.0, -431_694_791.0, -12_036_457.0)
v = PyVector(132.00, 632.90, -21.1)
path_ = path.PyFlightPath(system, r, v, 0)
period0 = 374942509.78053558 / 25
performance = path.PyPerformanceData(3000, 20000) # ve, thrust
burn_start_t = period0 / 4
maneuver = path.PyManeuver(path.PyManeuver.Types.Prograde, 100,
performance, 150, burn_start_t)
path_.add(maneuver)
# Get points to plot
x_pts = []
y_pts = []
for i in range(N_POINTS):
t = period0 / N_POINTS * i
kinematic_data: path.PyKinematicData = path_.predict(t)
x_pts.append(kinematic_data.r.x)
y_pts.append(kinematic_data.r.y)
burn_start_prediction = path_.predict(burn_start_t)
burn_start_pos = burn_start_prediction.r
# Plot
plt.figure(1)
plt.subplots_adjust(hspace=0.5, wspace=0.35)
plt.plot(0, 0, 'ro') # Body position.
plt.plot(x_pts, y_pts, 'r-') # line
plt.plot(burn_start_pos.x, burn_start_pos.y, 'ro') # current pos
plt.axis('equal')
plt.show()