def test_man_tangetial_linear(tangential):
orb = tangential
forward = 60
dv = 0.1
duration = timedelta(seconds=abs(forward / dv))
dv1 = orb.propagator._mat3 @ [0, dv, 0]
accel = (orb.propagator._mat3 @ [-1, 0, 0]) * 2 * orb.propagator.n * dv
man_start = orb.date + timedelta(seconds=10)
duration = timedelta(seconds=forward / dv)
man_stop = man_start + duration
orb.maneuvers = [
ImpulsiveMan(man_start, dv1),
ContinuousMan(man_start, duration, accel=accel),
ImpulsiveMan(man_stop, -dv1),
]
# ephem = orb.ephem(stop=man_stop + timedelta(hours=1), step=timedelta(seconds=60))
# plot_ephem(ephem)
orb2 = orb.propagate(man_stop + timedelta(seconds=120))
radial = 0 if orb.propagator.frame.orientation == "QSW" else 1
tan = 1 if orb.propagator.frame.orientation == "QSW" else 0
assert duration.total_seconds() == 600
assert np.isclose(orb2[radial], 0)
assert np.isclose(orb2[tan] - orb[tan], forward)
assert orb2[2] == orb[2]
def test_man_tangential_boost(tangential):
orb = tangential
man_start = orb.date + timedelta(seconds=60)
man_stop = man_start + timedelta(seconds=2 * np.pi / orb.propagator.n)
forward = 70 # Advance 70 m closer to the target
dv = forward * orb.propagator.n / (6 * np.pi)
orb.maneuvers = [
ImpulsiveMan(man_start, orb.propagator._mat3 @ [0, -dv, 0]),
ImpulsiveMan(man_stop, orb.propagator._mat3 @ [0, dv, 0]),
]
# ephem = orb.ephem(stop=man_stop + timedelta(hours=1), step=timedelta(seconds=60))
# plot_ephem(ephem)
orb2 = orb.propagate(man_stop + timedelta(seconds=120))
radial = 0 if orb.propagator.frame.orientation == "QSW" else 1
tan = 1 if orb.propagator.frame.orientation == "QSW" else 0
assert np.isclose(orb[radial], orb2[radial])
assert np.isclose(orb2[tan] - orb[tan], forward)
assert np.isclose(orb2[tan], -30)
assert orb[2] == orb2[2]
def test_man_impulsive(molniya_kepler):
# Test of a circularisation of a molniya orbit
# At apogee, this is roughly 1400 m/s
with raises(ValueError):
ImpulsiveMan(Date(2018, 9, 20, 13, 48, 21, 763091), (28, 0, 0, 0))
apo = find_event(molniya_kepler.iter(stop=timedelta(hours=26),
listeners=ApsideListener()),
'Apoapsis',
offset=1)
man = ImpulsiveMan(apo.date, (1427., 0, 0), frame="TNW")
# Check on the sensitivity of the find_event function
apo2 = find_event(molniya_kepler.iter(start=molniya_kepler.date +
timedelta(seconds=243, minutes=5),
stop=timedelta(hours=26),
listeners=ApsideListener()),
'Apoapsis',
offset=1)
assert abs(apo.date - apo2.date) < timedelta(seconds=1)
molniya_kepler.maneuvers = man
altitude = []
eccentricity = []
dates = []
for p in molniya_kepler.iter(stop=timedelta(hours=36)):
altitude.append(p.copy(form='spherical').r - p.frame.center.body.r)
eccentricity.append(p.copy(form="keplerian").e)
dates.append(p.date.datetime)
# plot_delta_a(dates, altitude, eccentricity)
# retrieve the index of the first point after the maneuver
man_idx = (np.array(dates) > man.date.datetime).argmax()
alt_before = np.mean(altitude[:man_idx])
alt_after = np.mean(altitude[man_idx:])
ecc_before = np.mean(eccentricity[:man_idx])
ecc_after = np.mean(eccentricity[man_idx:])
assert abs(ecc_before - 6.47e-1) < 2e-4
assert abs(ecc_after - 3e-3) < 2e-4
# assert abs(ecc_after - 6.57e-4) < 1e-6
assert str(man.date) == "2018-05-03T16:29:23.246451 UTC"
# 8'000 km increment in altitude
assert 8000000 < alt_after - alt_before < 8200000
def test_man_hohmann(kind, lower_circular):
"""Check stability of a Hohmann transfer to nullified radial distance
i.e. if the tangential distance does not evolve
"""
orb = lower_circular
man_start = orb.date + timedelta(seconds=60)
if kind == "impulive":
man_stop = man_start + timedelta(seconds=np.pi / orb.propagator.n)
else:
man_stop = timedelta(seconds=2 * np.pi / orb.propagator.n)
delta_a = 600
dv = 1.5 * orb.propagator.n * delta_a / 6
if kind == "impulive":
orb.maneuvers = [
ImpulsiveMan(man_start, orb.propagator._mat3 @ [0, dv, 0]),
ImpulsiveMan(man_stop, orb.propagator._mat3 @ [0, dv, 0]),
]
else:
orb.maneuvers = [
ContinuousMan(man_start,
man_stop,
dv=2 * orb.propagator._mat3 @ [0, dv, 0]),
]
# ephem = orb.ephem(stop=man_stop + timedelta(hours=1), step=timedelta(seconds=60))
# plot_ephem(ephem)
orb2 = orb.propagate(man_stop + timedelta(seconds=60))
orb3 = orb.propagate(man_stop + timedelta(seconds=120))
radial = 0 if orb.propagator.frame.orientation == "QSW" else 1
tan = 1 if orb.propagator.frame.orientation == "QSW" else 0
assert np.isclose(orb2[radial], orb3[radial])
assert np.isclose(orb2[tan], orb3[tan])
assert orb2[2] == orb3[2]
# Propagate during the continuous maneuver
if kind == "continuous":
orb4 = orb.propagate(man_start + timedelta(minutes=25))
assert orb.maneuvers[0].check(orb4.date)
if orb.propagator.frame.orientation == "QSW":
assert -delta_a < orb4[radial] < 0
else:
assert delta_a > orb4[radial] > 0
def orbit_man(orbit):
orbit = orbit.copy()
orbit.propagator = KeplerNum(get_body("Earth"), timedelta(seconds=60))
orbit.maneuvers = [
ImpulsiveMan(
Date(2008, 9, 20, 12, 41, 9, 984493),
[280, 0, 0],
frame="TNW",
comment="Maneuver 1",
),
ImpulsiveMan(Date(2008, 9, 20, 13, 33, 11, 374985), [270, 0, 0],
frame="TNW"),
]
return orbit
def test_man_eccentric_boost(kind, tangential):
orb = tangential
man_start = orb.date + timedelta(seconds=60)
if kind == "impulive":
man_stop = man_start + timedelta(seconds=np.pi / orb.propagator.n)
else:
man_stop = timedelta(seconds=2 * np.pi / orb.propagator.n)
forward = 70 # Advance 70 m closer to the target
dv = forward * orb.propagator.n / 4
if kind == "impulive":
orb.maneuvers = [
ImpulsiveMan(man_start, orb.propagator._mat3 @ [-dv, 0, 0]),
ImpulsiveMan(man_stop, orb.propagator._mat3 @ [-dv, 0, 0]),
]
else:
orb.maneuvers = ContinuousMan(man_start,
man_stop,
dv=2 *
orb.propagator._mat3 @ [-dv, 0, 0])
# ephem = orb.ephem(stop=man_stop + timedelta(hours=1), step=timedelta(seconds=60))
# plot_ephem(ephem)
orb2 = orb.propagate(man_stop + timedelta(seconds=120))
radial = 0 if orb.propagator.frame.orientation == "QSW" else 1
tan = 1 if orb.propagator.frame.orientation == "QSW" else 0
assert np.isclose(orb[radial], orb2[radial])
assert np.isclose(orb2[tan] - orb[tan], forward)
assert np.isclose(orb2[tan], -30)
assert orb[2] == orb2[2]
1 25544U 98067A 18124.55610684 .00001524 00000-0 30197-4 0 9997
2 25544 51.6421 236.2139 0003381 47.8509 47.6767 15.54198229111731"""
).orbit()
start = orb.date
stop = timedelta(minutes=300)
step = timedelta(seconds=60)
# Changing the propagator to Keplerian, as SGP4 is not able to perform maneuvers
orb.propagator = KeplerNum(step, bodies=get_body("Earth"))
# Research for the next perigee
perigee = find_event(orb.iter(stop=stop, listeners=ApsideListener()),
'Periapsis')
man1 = ImpulsiveMan(perigee.date, (280, 0, 0), frame="TNW")
orb.maneuvers = [man1]
dates1, alt1 = [], []
# Research for the next apogee after the first maneuver
apogee = find_event(
orb.iter(start=perigee.date - step * 10,
stop=stop,
listeners=ApsideListener()), 'Apoapsis')
# apogee = find_event(orb.iter(stop=stop, listeners=ApsideListener()), 'Apoapsis', offset=1)
# Adding the second maneuver to the orbit
man2 = ImpulsiveMan(apogee.date, (270, 0, 0), frame="TNW")
orb.maneuvers.append(man2)