def test_vel_mag():
r = 5.04 * constants.earth.radius
a = 6 * constants.earth.radius
mu = constants.earth.mu
v_true = 3.79259
v = maneuver.vel_mag(r, a, mu)
np.testing.assert_allclose(v, v_true, rtol=1e-4)
"""Problem 12 HW6 2017
"""
from astro import kepler, maneuver, constants
import numpy as np
r1 = 8000
r2 = 42160
i1 = np.deg2rad(30)
i2 = 0
mu = constants.earth.mu
# hohmann transfer and combined plane change at apoapsis
at, pt, et = kepler.perapo2aecc(r1, r2)
vt1 = maneuver.vel_mag(r1, at, mu)
vt2 = maneuver.vel_mag(r2, at, mu)
v1 = maneuver.vel_mag(r1, r1, mu)
v2 = maneuver.vel_mag(r2, r2, mu)
dv1, alpha1, beta1 = maneuver.delta_v_solve_planar(v1, vt1, 0, 0)
dv2, beta2, _ = maneuver.delta_v_solve_planar(vt2, v2, i1, 0)
print('Combined plane change at apoapsis')
print('V1 : {} , V2 : {} km/sec'.format(v1, v2))
print('VT1 : {} , VT2 : {} km/sec'.format(vt1, vt2))
print('DV1 : {} km/sec'.format(dv1))
print('DV2 : {} km/sec'.format(dv2))
print('Beta (outofplane) : {} deg'.format(np.rad2deg(beta2)))
"""Solve bielliptical problem 2 2017 HW6 """ from astro import kepler, maneuver, constants import numpy as np mu = constants.moon.mu rm = constants.moon.radius r1 = 100 + rm r2 = 100 + rm ri = 17000 delta_inc = np.pi/2 v1 = maneuver.vel_mag(r1, r1, mu) v2 = maneuver.vel_mag(r2, r2, mu) # bielliptical transfer orbit a_bi, p_bi, ecc_bi= kepler.perapo2aecc(r1, ri) # simple plane change at current altitude dv_current = maneuver.simple_plane_change(v1, delta_inc) # first manuever v1_bi = maneuver.vel_mag(r1, a_bi, mu) dv1 = np.absolute(v1 - v1_bi) # plane change at apoapsis of bielliptical transfer v2_bi = maneuver.vel_mag(ri, a_bi, mu) dv2 = maneuver.simple_plane_change(v2_bi, delta_inc)
"""Bielliptical transfer Problem 10 HW6 2017 """ from astro import kepler, maneuver, constants import numpy as np r1 = 8000 r2 = 120000 ri = 280000 mu = constants.earth.mu v1 = maneuver.vel_mag(r1, r1, mu) v2 = maneuver.vel_mag(r2, r2, mu) # bielliptical transfer orbit ab1, pb1, eccb1 = kepler.perapo2aecc(r1, ri) ab2, pb2, eccb2 = kepler.perapo2aecc(r2, ri) # first manuever vb1 = maneuver.vel_mag(r1, ab1, mu) dv1 = np.absolute(v1 - vb1) # second manuever at intermediate radius vb1i = maneuver.vel_mag(ri, ab1, mu) vb2i = maneuver.vel_mag(ri, ab2, mu) dv2 = np.absolute(vb2i - vb1i) # third maneuver vb2 = maneuver.vel_mag(r2, ab2, mu) dv3 = np.absolute(v2 - vb2)
import pdb ra = 7000 rb = 14000 mu = constants.earth.mu # define hyperbolic arrival orbit va1 = 12 e_h = va1**2 / 2 - mu / ra a_h = -mu / e_h / 2 ecc_h = ra / np.absolute(a_h) + 1 p_h = kepler.semilatus_rectum(np.absolute(a_h), ecc_h) nu_h = 0 # hohmann transfer from hyperbolic orbit to circular orbit rb a_t, p_t, ecc_t = kepler.perapo2aecc(ra, rb) vt1 = maneuver.vel_mag(ra, a_t, mu) dva1, _, toft, phaset = maneuver.hohmann(ra, rb, ecc_h, 0, 0, 0, mu) # final orbit mean motion n2 = np.sqrt(mu / rb**3) angle = n2 * toft p2 = 2 * np.pi * np.sqrt(rb**3 / mu) phasing_period = p2 - toft # design of phasing orbit a_p = kepler.period2sma(phasing_period, mu) rc = a_p * 2 - rb a_p, p_p, ecc_p = kepler.perapo2aecc(rc, rb) # hohmann from transfer ellipse to phasing orbit
"""Problem 9 HW6 2017
"""
from astro import maneuver, kepler, constants
import numpy as np
ra = 25000
rb = 40000
rc = 10000
rd = 55000
mu = constants.earth.mu
# orbit 1 properties
a1, p1, ecc1 = kepler.perapo2aecc(ra, rb)
va1 = maneuver.vel_mag(ra, a1, mu)
vb1 = maneuver.vel_mag(rb, a1, mu)
# orbit 2 properties
a2, p2, ecc2 = kepler.perapo2aecc(rc, rd)
vc2 = maneuver.vel_mag(rc, a2, mu)
vd2 = maneuver.vel_mag(rd, a2, mu)
# A to C Hohmann trasnfer
at1, pt1, ecct1 = kepler.perapo2aecc(rc, ra)
vat = maneuver.vel_mag(ra, at1, mu)
vct = maneuver.vel_mag(rc, at1, mu)
dv1, dv2, tof1, _ = maneuver.hohmann(ra, rc, ecc1, ecc2, 0, 0, mu)
dvt1 = np.absolute(dv1) + np.absolute(dv2)
print('A to C hohmann transfer')
print('Semimajor axis : {} km'.format(at1))
"""Hohmann Transfer example Problem 5 HW 5 2017
"""
from astro import constants, kepler, maneuver
import numpy as np
mu = constants.earth.mu
# initial orbit
r1 = 1.25 * constants.earth.radius
r2 = 6.6 * constants.earth.radius
at, pt, ecct = kepler.perapo2aecc(r1, r2)
v1 = maneuver.vel_mag(r1, r1, mu)
v2 = maneuver.vel_mag(r2, r2, mu)
dv1, dv2, tof, phase_angle = maneuver.hohmann(r1, r2, 0, 0, 0, np.pi, mu)
S = maneuver.synodic_period(r1, r2, mu)
print('V1 : {} km/sec'.format(v1))
print('DV1 : {} km/sec'.format(dv1))
print('V2 : {} km/sec'.format(v2))
print('DV2 : {} km/sec'.format(dv2))
print('TOF : {} sec = {} hr'.format(tof, tof / 3600))
print('Phase Angle : {} deg'.format(np.rad2deg(phase_angle)))
print('Synodic Period : {} sec = {} hr'.format(S, S / 3600))