def test_clamp_to(self, mock_conn):
"""Check that clamp_to() works."""
transfer = HohmannTransfer()
self.assertEqual(transfer.clamp_to(-10, 360), 350)
self.assertEqual(transfer.clamp_to(20, 360), 20)
self.assertEqual(transfer.clamp_to(390, 360), 30)
def test_sma_from_period(self, mock_conn):
"""Check that sma_from_period() works."""
vessel = mock_conn().space_center.active_vessel
vessel.orbit.body.gravitational_parameter = 1
transfer = HohmannTransfer()
self.assertAlmostEqual(transfer.sma_from_period(16 * pi), 4)
def test_target_altitude(self, mock_conn):
"""Check that target_altitude sets target_sma."""
mock_conn().space_center.active_vessel.orbit.body.equatorial_radius = 1
transfer = HohmannTransfer()
transfer.target_altitude = 10
self.assertEqual(transfer.target_altitude, 10)
self.assertEqual(transfer.target_sma, 11)
def test_target_period(self, mock_conn):
"""Check that target_period sets target_sma."""
vessel = mock_conn().space_center.active_vessel
vessel.orbit.body.gravitational_parameter = 1
transfer = HohmannTransfer()
transfer.target_period = 16 * pi
self.assertAlmostEqual(transfer.target_period, 16 * pi)
self.assertAlmostEqual(transfer.target_sma, 4)
def test_transfer_to_synchronous_orbit(self, mock_conn):
"""Check transfer_to_synchronous_orbit sets target_sma."""
vessel = mock_conn().space_center.active_vessel
vessel.orbit.semi_major_axis = 4
vessel.orbit.body.gravitational_parameter = 1
vessel.orbit.body.rotational_period = 20
transfer = HohmannTransfer()
transfer.transfer_to_synchronous_orbit()
self.assertAlmostEqual(transfer.target_period, 20)
def test_initial_phase(self, mock_conn):
"""Check that initial_phase is set from active vessel."""
mock_conn().space_center.active_vessel.flight().longitude = 20
transfer = HohmannTransfer()
self.assertEqual(transfer.initial_phase, 20)
def test_transfer_sma(self, mock_conn):
"""Check that transfer_sma is the average of initial & target smas."""
mock_conn().space_center.active_vessel.orbit.semi_major_axis = 10
transfer = HohmannTransfer(target_sma=30)
self.assertEqual(transfer.transfer_sma, 20)
def test_init_target_sma_no_karg(self, mock_conn):
"""Check that __init__ w/o karg sets target_sma to inital_sma."""
mock_conn().space_center.active_vessel.orbit.semi_major_axis = 10
transfer = HohmannTransfer()
self.assertEqual(transfer.target_sma, 10)
def test_transfer_to_rendezvous(self, mock_conn):
"""Should set target_sma & delay with a target."""
vessel = mock_conn().space_center.active_vessel
vessel.orbit.semi_major_axis = 4
vessel.orbit.body.gravitational_parameter = 1
vessel.flight().longitude = 0
target = mock_conn().space_center.target_vessel
target.orbit.semi_major_axis = 9
target.flight().longitude = 20
transfer = HohmannTransfer()
transfer.transfer_to_rendezvous()
self.assertAlmostEqual(transfer.target_sma, 9)
self.assertAlmostEqual(transfer.target_phase, 20)
def test_no_krpc_connection(self):
"""Server unreachable should raise ConnectionRefusedError."""
try:
HohmannTransfer()
except Exception as e:
self.assertIsInstance(e, ConnectionRefusedError)
return
def test_initial_sma(self, mock_conn):
"""Check that inital_sma is set from active vessel."""
mock_conn().space_center.active_vessel.orbit.semi_major_axis = 10
transfer = HohmannTransfer()
self.assertEqual(transfer.initial_sma, 10)
def test_transfer_to_rendezvous_no_target(self, mock_conn):
"""Should warn but not raise AttributeError w/o target."""
mock_conn().space_center.target_vessel = None
transfer = HohmannTransfer()
with self.subTest('Does not raise AttributeError'):
with patch('sys.stdout') as mock_stdout:
try:
transfer.transfer_to_rendezvous()
except AttributeError:
self.fail('Should have caught the AttributeError')
calls = [call('No target found: transfer unchanged.')]
with self.subTest('Writes warning to stdout'):
mock_stdout.write.assert_has_calls(calls)
def test_repr(self, mock_conn):
"""Check that the __repr__() method works."""
actual_str = repr(HohmannTransfer(target_sma=2000000.0, delay=100.0))
expect_str = 'HohmannTransfer(target_sma=2000000.0, delay=100.0)'
self.assertEqual(actual_str, expect_str)
def test_add_nodes(self, mock_conn):
"""Should call KRPC's add_node() twice with the correct kargs."""
vessel = mock_conn().space_center.active_vessel
vessel.orbit.semi_major_axis = 2
vessel.orbit.body.gravitational_parameter = 1
mock_conn().space_center.ut = 0
transfer = HohmannTransfer(target_sma=3)
transfer.add_nodes()
expect_calls = [
call(prograde=transfer.initial_dV, ut=0),
call(prograde=transfer.final_dV, ut=transfer.transfer_time)
]
control = mock_conn().space_center.active_vessel.control
control.add_node.assert_has_calls(expect_calls)
def test_mu(self, mock_conn):
"""Check that gravitational parameter is set from active vessel."""
vessel = mock_conn().space_center.active_vessel
vessel.orbit.body.gravitational_parameter = 10
transfer = HohmannTransfer()
self.assertEqual(transfer.mu, 10)
def test_initial_altitude(self, mock_conn):
"""Check that initial_altitude is set from active vessel."""
vessel = mock_conn().space_center.active_vessel
vessel.orbit.semi_major_axis = 10
vessel.orbit.body.equatorial_radius = 1
transfer = HohmannTransfer()
self.assertEqual(transfer.initial_altitude, 9)
def test_initial_period(self, mock_conn):
"""Check that initial_period is set from active vessel."""
vessel = mock_conn().space_center.active_vessel
vessel.orbit.semi_major_axis = 4
vessel.orbit.body.gravitational_parameter = 1
transfer = HohmannTransfer()
self.assertAlmostEqual(transfer.initial_period, 16 * pi)
def test_transfer_time(self, mock_conn):
"""Should set transfer_time from active vessel & target_sma."""
vessel = mock_conn().space_center.active_vessel
vessel.orbit.semi_major_axis = 2
vessel.orbit.body.gravitational_parameter = 1
transfer = HohmannTransfer(target_sma=6)
self.assertAlmostEqual(transfer.transfer_time, 8 * pi)
def test_phase_change(self, mock_conn):
"""Check that phase_change is set from active vessel & target_sma."""
vessel = mock_conn().space_center.active_vessel
vessel.orbit.semi_major_axis = 2
vessel.orbit.body.gravitational_parameter = 1
transfer = HohmannTransfer(target_sma=3)
self.assertAlmostEqual(transfer.phase_change, 43.0693606237085)
def test_final_dV(self, mock_conn):
"""Check that final_dV is set from active vessel & target_sma."""
vessel = mock_conn().space_center.active_vessel
vessel.orbit.semi_major_axis = 16
vessel.orbit.body.gravitational_parameter = 8
transfer = HohmannTransfer(target_sma=2)
self.assertAlmostEqual(transfer.final_dV, -2 / 3)
def test_relative_period(self, mock_conn):
"""Should set relative_period from active vessel & target_sma."""
vessel = mock_conn().space_center.active_vessel
vessel.orbit.semi_major_axis = 4
vessel.orbit.body.gravitational_parameter = 1
transfer = HohmannTransfer(target_sma=9)
self.assertAlmostEqual(transfer.relative_period,
pi * 16 * 54 / (16 - 54))
def test_target_phase(self, mock_conn):
"""Check that target_phase sets itself (clamped) as well as delay."""
vessel = mock_conn().space_center.active_vessel
vessel.orbit.semi_major_axis = 2
vessel.orbit.body.gravitational_parameter = 1
vessel.flight().longitude = 10
transfer = HohmannTransfer(target_sma=3)
target_phase_baseline = transfer.initial_phase + transfer.phase_change
with self.subTest('Target already in position.'):
transfer.target_phase = target_phase_baseline
self.assertAlmostEqual(transfer.target_phase,
target_phase_baseline)
self.assertAlmostEqual(transfer.delay, 0)
with self.subTest('Target 90 degrees ahead.'):
transfer.target_phase = 90 + target_phase_baseline
self.assertAlmostEqual(transfer.target_phase,
90 + target_phase_baseline)
self.assertAlmostEqual(transfer.delay,
0.25 * abs(transfer.relative_period))
with self.subTest('Target 90 degrees behind.'):
transfer.target_phase = -90 + target_phase_baseline
self.assertAlmostEqual(transfer.target_phase,
270 + target_phase_baseline)
self.assertAlmostEqual(transfer.delay,
0.75 * abs(transfer.relative_period))
with self.subTest('Target a full turn & a third degrees ahead.'):
transfer.target_phase = 480 + target_phase_baseline
self.assertAlmostEqual(transfer.target_phase,
120 + target_phase_baseline)
self.assertAlmostEqual(transfer.delay,
1 / 3 * abs(transfer.relative_period))
def test_str(self, mock_conn):
"""Check that the __str__() method works."""
vessel = mock_conn().space_center.active_vessel
vessel.orbit.semi_major_axis = 10**6
vessel.orbit.body.gravitational_parameter = 10**12
vessel.orbit.body.equatorial_radius = 1
actual_str = str(HohmannTransfer(target_sma=2 * 10**6))
expect_str = 'Hohmann transfer from 1000 km altitude to '
expect_str += '2000 km altitude:\n'
expect_str += ' 1. Wait: 0 seconds to burn: '
expect_str += '154.7 m/s prograde.\n'
expect_str += ' 2. Wait: 5771 seconds to burn: '
expect_str += '129.8 m/s prograde.\n'
self.assertEqual(actual_str, expect_str)
def test_init_delay(self, mock_conn):
"""Check that __init__ with delay karg sets it."""
transfer = HohmannTransfer(delay=10)
self.assertEqual(transfer.delay, 10)
def test_init_delay_no_karg(self, mock_conn):
"""Check that __init__ w/o karg sets delay to zero."""
transfer = HohmannTransfer()
self.assertEqual(transfer.delay, 0)
def test_init_target_sma(self, mock_conn):
"""Check that __init__ with target_sma karg sets it."""
transfer = HohmannTransfer(target_sma=10)
self.assertEqual(transfer.target_sma, 10)
def test_krpc_connection(self, mock_conn):
"""Check that __init__ connects to KRPC server."""
HohmannTransfer()
mock_conn.assert_called_once_with(name='HohmannTransfer')
def test_delay(self, mock_conn):
"""Check that target_sma can be set."""
transfer = HohmannTransfer()
transfer.delay = 10
self.assertEqual(transfer.delay, 10)
""" Adds two nodes for a Hohmann transfer to a given altitude. Currently checks that the initial orbit is reasonably circular. """ from HohmannTransfer import HohmannTransfer DELAY = 180 # in seconds transfer = HohmannTransfer(delay=DELAY) TARGET_ALTITUDE = 100 * 1000 # in meters transfer.target_altitude = TARGET_ALTITUDE print(transfer) transfer.add_nodes()
""" Adds two nodes for a Hohmann transfer to synchronous orbit around current body. Currently checks that the initial orbit is reasonably circular. """ from HohmannTransfer import HohmannTransfer transfer = HohmannTransfer() transfer.transfer_to_synchronous_orbit() KSC_LONGITUDE = 285.425 transfer.target_phase = KSC_LONGITUDE print(transfer) transfer.add_nodes()
