def test_hyperbolic_orbital_parameters(self):
# Unlike the elliptical test, this tests our favourite extra-solar
# visitor to make sure we can calculate Keplerian orbital
# characteristics from its orbital state vectors! That's right, we're
# talking about Sedna! The expected values are arrived at through
# calculation, and also
# http://orbitsimulator.com/formulas/OrbitalElements.html
physics_state = common.load_savefile(
common.savefile('tests/sedna.json'))
sun = physics_state[0]
oumuamua = physics_state[1]
expected_semimajor_axis = -71231070.14146987
self.assertAlmostEqual(calc.semimajor_axis(oumuamua, sun),
expected_semimajor_axis,
delta=abs(0.01 * expected_semimajor_axis))
expected_eccentricity = 1644.477
self.assertAlmostEqual(calc.fastnorm(calc.eccentricity(oumuamua, sun)),
expected_eccentricity,
delta=0.01 * expected_eccentricity)
expected_periapsis = 1.1714e11 # Through calculation
self.assertAlmostEqual(calc.periapsis(sun, oumuamua) + oumuamua.r,
expected_periapsis,
delta=0.01 * 78989185420.15271)
def test_elliptical_orbital_parameters(self):
# Again, see
# https://www.wolframalpha.com/input/?i=International+Space+Station
# For these expected values
physics_state = common.load_savefile(
common.savefile('tests/gui-test.json'))
iss = physics_state[0]
earth = physics_state[1]
# The semiaxes are relatively close to expected.
self.assertAlmostEqual(calc.semimajor_axis(iss, earth),
6785e3,
delta=0.01 * earth.r)
# The eccentricity is within 1e-6 of the expected.
self.assertAlmostEqual(calc.fastnorm(calc.eccentricity(iss, earth)),
5.893e-4,
delta=1e-3)
# The apoapsis is relatively close to expected.
self.assertAlmostEqual(calc.apoapsis(iss, earth),
418.3e3,
delta=0.01 * earth.r)
# The periapsis is relatively close to expected.
self.assertAlmostEqual(calc.periapsis(iss, earth),
410.3e3,
delta=0.01 * earth.r)