def change_inc_ecc(ss_0, ecc_f, inc_f, f):
"""Guidance law from the model.
Thrust is aligned with an inertially fixed direction perpendicular to the
semimajor axis of the orbit.
Parameters
----------
ss_0 : Orbit
Initial orbit, containing all the information.
ecc_f : float
Final eccentricity.
inc_f : float
Final inclination.
f : float
Magnitude of constant acceleration.
"""
# We fix the inertial direction at the beginning
ecc_0 = ss_0.ecc.value
if ecc_0 > 0.001: # Arbitrary tolerance
ref_vec = ss_0.e_vec / ecc_0
else:
ref_vec = ss_0.r / norm(ss_0.r)
h_unit = ss_0.h_vec / norm(ss_0.h_vec)
thrust_unit = cross(h_unit, ref_vec) * np.sign(ecc_f - ecc_0)
inc_0 = ss_0.inc.to(u.rad).value
argp = ss_0.argp.to(u.rad).value
beta_0_ = beta(ecc_0, ecc_f, inc_0, inc_f, argp)
@njit
def a_d(t0, u_, k):
r = u_[:3]
v = u_[3:]
nu = rv2coe(k, r, v)[-1]
beta_ = beta_0_ * np.sign(
np.cos(nu)) # The sign of ß reverses at minor axis crossings
w_ = cross(r, v) / norm(cross(r, v))
accel_v = f * (np.cos(beta_) * thrust_unit + np.sin(beta_) * w_)
return accel_v
delta_V, beta_, t_f = extra_quantities(
ss_0.attractor.k.to(u.km**3 / u.s**2).value,
ss_0.a.to(u.km).value,
ecc_0,
ecc_f,
inc_0,
inc_f,
argp,
f,
)
return a_d, delta_V, beta_, t_f
def change_inc_ecc(ss_0, ecc_f, inc_f, f):
"""Guidance law from the model.
Thrust is aligned with an inertially fixed direction perpendicular to the
semimajor axis of the orbit.
Parameters
----------
ss_0 : Orbit
Initial orbit, containing all the information.
ecc_f : float
Final eccentricity.
inc_f : float
Final inclination.
f : float
Magnitude of constant acceleration.
"""
# We fix the inertial direction at the beginning
ecc_0 = ss_0.ecc.value
if ecc_0 > 0.001: # Arbitrary tolerance
ref_vec = ss_0.e_vec / ecc_0
else:
ref_vec = ss_0.r / norm(ss_0.r)
h_unit = ss_0.h_vec / norm(ss_0.h_vec)
thrust_unit = cross(h_unit, ref_vec) * np.sign(ecc_f - ecc_0)
inc_0 = ss_0.inc.to(u.rad).value
argp = ss_0.argp.to(u.rad).value
beta_0_ = beta(ecc_0, ecc_f, inc_0, inc_f, argp)
def a_d(t0, u_, k):
r = u_[:3]
v = u_[3:]
nu = rv2coe(k, r, v)[-1]
beta_ = beta_0_ * np.sign(
np.cos(nu)
) # The sign of ß reverses at minor axis crossings
w_ = cross(r, v) / norm(cross(r, v))
accel_v = f * (np.cos(beta_) * thrust_unit + np.sin(beta_) * w_)
return accel_v
delta_V, beta_, t_f = extra_quantities(
ss_0.attractor.k.to(u.km ** 3 / u.s ** 2).value,
ss_0.a.to(u.km).value,
ecc_0,
ecc_f,
inc_0,
inc_f,
argp,
f,
)
return a_d, delta_V, beta_, t_f