def test_perifocal_points_to_perigee():
_d = 1.0 * u.AU # Unused distance
_ = 0.5 * u.one # Unused dimensionless value
_a = 1.0 * u.deg # Unused angle
ss = State.from_classical(Sun, _d, _, _a, _a, _a, _a)
p, _, _ = ss.pqw()
assert_almost_equal(p, ss.e_vec / ss.ecc)
def test_default_time_for_new_state():
_d = 1.0 * u.AU # Unused distance
_ = 0.5 * u.one # Unused dimensionless value
_a = 1.0 * u.deg # Unused angle
_body = Sun # Unused body
expected_epoch = time.Time("J2000", scale='utc')
ss = State.from_classical(_body, _d, _, _a, _a, _a, _a)
assert ss.epoch == expected_epoch
def test_state_raises_unitserror_if_elements_units_are_wrong():
_d = 1.0 * u.AU # Unused distance
_ = 0.5 * u.one # Unused dimensionless value
_a = 1.0 * u.deg # Unused angle
wrong_angle = 1.0 * u.AU
with pytest.raises(u.UnitsError) as excinfo:
ss = State.from_classical(Sun, _d, _, _a, _a, _a, wrong_angle)
assert ("UnitsError: Units must be consistent"
in excinfo.exconly())
def test_apply_maneuver_changes_epoch():
_d = 1.0 * u.AU # Unused distance
_ = 0.5 * u.one # Unused dimensionless value
_a = 1.0 * u.deg # Unused angle
ss = State.from_classical(Sun, _d, _, _a, _a, _a, _a)
dt = 1 * u.h
dv = [0, 0, 0] * u.km / u.s
ss_new = ss.apply_maneuver([(dt, dv)])
assert ss_new.epoch == ss.epoch + dt
def test_state_has_elements_given_in_constructor():
# Mars data from HORIZONS at J2000
a = 1.523679 * u.AU
ecc = 0.093315 * u.one
p = a * (1 - ecc**2)
inc = 1.85 * u.deg
raan = 49.562 * u.deg
argp = 286.537 * u.deg
nu = 23.33 * u.deg
ss = State.from_classical(Sun, p, ecc, inc, raan, argp, nu)
assert ss.coe() == (p, ecc, inc, raan, argp, nu)
def test_apply_zero_maneuver_returns_equal_state():
_d = 1.0 * u.AU # Unused distance
_ = 0.5 * u.one # Unused dimensionless value
_a = 1.0 * u.deg # Unused angle
ss = State.from_classical(Sun, _d, _, _a, _a, _a, _a)
dt = 0 * u.s
dv = [0, 0, 0] * u.km / u.s
ss_new = ss.apply_maneuver([(dt, dv)])
assert_almost_equal(ss_new.r.to(u.km).value,
ss.r.to(u.km).value)
assert_almost_equal(ss_new.v.to(u.km / u.s).value,
ss.v.to(u.km / u.s).value)
def test_perigee_and_apogee():
expected_r_a = 500 * u.km
expected_r_p = 300 * u.km
a = (expected_r_a + expected_r_p) / 2
ecc = expected_r_a / a - 1
p = a * (1 - ecc**2)
_a = 1.0 * u.deg # Unused angle
ss = State.from_classical(Earth, p, ecc, _a, _a, _a, _a)
assert_almost_equal(ss.r_a.to(u.km).value,
expected_r_a.to(u.km).value)
assert_almost_equal(ss.r_p.to(u.km).value,
expected_r_p.to(u.km).value)
def test_convert_from_rv_to_coe():
# Data from Vallado, example 2.6
attractor = Earth
p = 11067.790 * u.km
ecc = 0.83285 * u.one
inc = 87.87 * u.deg
raan = 227.89 * u.deg
argp = 53.38 * u.deg
nu = 92.335 * u.deg
expected_r = [6525.344, 6861.535, 6449.125] # km
expected_v = [4.902276, 5.533124, -1.975709] # km / s
r, v = State.from_classical(Earth, p, ecc, inc, raan, argp, nu).rv()
assert_array_almost_equal(r.value, expected_r, decimal=1)
assert_array_almost_equal(v.value, expected_v, decimal=5)
def test_state_has_individual_elements():
a = 1.523679 * u.AU
ecc = 0.093315 * u.one
p = a * (1 - ecc**2)
inc = 1.85 * u.deg
raan = 49.562 * u.deg
argp = 286.537 * u.deg
nu = 23.33 * u.deg
ss = State.from_classical(Sun, p, ecc, inc, raan, argp, nu)
assert ss.a == a
assert ss.ecc == ecc
assert ss.inc == inc
assert ss.raan == raan
assert ss.argp == argp
assert ss.nu == nu
# coding: utf-8
"""Example data.
"""
from astropy import time
from astropy import units as u
from poliastro.bodies import Earth
from poliastro.twobody import State
# Taken from Plyades (c) 2012 Helge Eichhorn (MIT License)
iss = State.from_vectors(Earth,
[8.59072560e2, -4.13720368e3, 5.29556871e3] * u.km,
[7.37289205, 2.08223573, 4.39999794e-1] * u.km / u.s,
time.Time("2013-03-18 12:00", scale='utc'))
molniya = State.from_classical(Earth,
26600 * u.km, 0.75 * u.one, 63.4 * u.deg,
0 * u.deg, 270 * u.deg, 80 * u.deg)
def test_state_has_attractor_given_in_constructor():
_d = 1.0 * u.AU # Unused distance
_ = 0.5 * u.one # Unused dimensionless value
_a = 1.0 * u.deg # Unused angle
ss = State.from_classical(Sun, _d, _, _a, _a, _a, _a)
assert ss.attractor == Sun