ast2000tools.space_mission.LandingSequence¶

class ast2000tools.space_mission.LandingSequence(mission, assume_uniform_gravity_atmosphere=True, verbose=True)¶

Bases: ast2000tools.space_mission._SpacecraftJourney

Represents a landing process with your spacecraft at the destination planet.

Note

Do not create instances of this class directly, use begin_landing_sequence() instead.

Raises

RuntimeError – When called before the destination of the interplanetary travel has been recorded.
RuntimeError – When the recorded position is not sufficiently close to the destination planet.

Methods

`activate_landing_thruster`()	Activates the landing thruster.
`adjust_landing_thruster`([force, min_height])	Modifies landing thruster parameters.
`adjust_parachute_area`(area)	Sets the parachute area.
`boost`(delta_v)	Adds the given velocity difference to the current spacecraft velocity.
`deploy_parachute`()	Deploys the parachute.
`fall`(duration[, tolerance])	Integrates the spacecraft/lander trajectory for a given duration and updates the current position and velocity.
`fall_until_time`(end_time[, tolerance])	Integrates the spacecraft/lander trajectory until a given end time and updates the current position and velocity.
`finish_video`([filename, number_of_frames, …])	Ends the recording and generates a corresponding video viewable in MCAst.
`launch_lander`(delta_v)	Launches the landing module from the spacecraft with the given boost.
`look_in_direction_of_motion`([…])	Makes the camera point towards a given angle relative to the direction of motion.
`look_in_direction_of_planet`([planet_idx, …])	Makes the camera point towards a given angle relative to the direction of the planet.
`look_in_fixed_direction`([polar_angle, …])	Orients the camera in a fixed direction specified by the given spherical angles.
`orient`()	Returns the current time, position and velocity for the spacecraft/lander.
`restart`()	Resets the spacecraft and system to the state at the beginning of the landing sequence.
`set_camera_up_vector`(up_x, up_y, up_z)	Specifies the up-vector to use for the camera.
`start_video`()	Starts recording what the spacecraft/lander camera sees.
`take_picture`([filename])	Generates a picture viewable in MCAst, with framing decided by the current spacecraft/lander camera orientation.

Attributes

`lander_launched`	Whether the landing module has been launched.
`landing_thruster_activated`	Whether the landing thruster has been activated.
`mission`	The mission that the spacecraft journey is associated with.
`parachute_broken`	Whether the parachute was destroyed.
`parachute_deployed`	Whether the parachute has been deployed.
`reached_surface`	Whether the surface has been reached.
`system`	The solar system in which the spacecraft journey takes place.
`verbose`	Whether non-essential messages will be printed during the journey.
`video_active`	Whether video is currently being recorded as the spacecraft moves.

property mission¶

The mission that the spacecraft journey is associated with.

Type: SpaceMission

property system¶

The solar system in which the spacecraft journey takes place.

Type: ast2000tools.solar_system.SolarSystem

property verbose¶

Whether non-essential messages will be printed during the journey.

Type: bool

property video_active¶

Whether video is currently being recorded as the spacecraft moves.

Type: bool

property lander_launched¶

Whether the landing module has been launched.

Type: bool

property parachute_deployed¶

Whether the parachute has been deployed.

Type: bool

property parachute_broken¶

Whether the parachute was destroyed.

Type: bool

property landing_thruster_activated¶

Whether the landing thruster has been activated.

Type: bool

property reached_surface¶

Whether the surface has been reached.

Type: bool

adjust_parachute_area(area)¶

Sets the parachute area.

Parameters: area (float) – The area to use for the parachute, in square meters.
Raises: RuntimeError – When the parachute has already been deployed.

adjust_landing_thruster(force=None, min_height=None)¶

Modifies landing thruster parameters.

Note

The default force and minimum height are both zero.

Parameters

force (float, optional) – The force to use for the landing thruster, in Newtons. By default, the force remains at the previous value.
min_height (float, optional) – The height below which the thruster will be automatically activated, in meters. Cannot exceed 500 m. By default, the minimum height remains at the previous value.

Raises

RuntimeError – When the landing thrusted has already been activated.

fall(duration, tolerance=1e-09)¶

Integrates the spacecraft/lander trajectory for a given duration and updates the current position and velocity.

Parameters

duration (float) – The duration to coast, in seconds.
tolerance (float, optional) – The relative error tolerance to use when integrating the trajectory. Default is 10^-9, which should be fine for the majority of cases.

fall_until_time(end_time, tolerance=1e-09)¶

Integrates the spacecraft/lander trajectory until a given end time and updates the current position and velocity.

Parameters

end_time (float) – The time to stop coasting, in seconds.
tolerance (float, optional) – The relative error tolerance to use when integrating the trajectory. Default is 10^-9, which should be fine for the majority of cases.

boost(delta_v)¶

Adds the given velocity difference to the current spacecraft velocity.

Parameters

delta_v (1-D array_like) – Array of shape (3,) containing the x, y and z-component of the change in velocity, in meters per second.

Raises

RuntimeError – When the landing module has been launched.
RuntimeError – When the lander has already been able to land.

launch_lander(delta_v)¶

Launches the landing module from the spacecraft with the given boost.

Parameters

delta_v (1-D array_like) – Array of shape (3,) containing the x and y-component of the change in velocity, in meters per seconds.

Raises

RuntimeError – When the landing module has already been launched.
RuntimeError – When the spacecraft has already been able to land.

deploy_parachute()¶

Deploys the parachute.

Raises

RuntimeError – When the parachute has already been deployed.
RuntimeError – When the lander has already been able to land.

activate_landing_thruster()¶

Activates the landing thruster.

Note

Does nothing if the lander is farther than 500 m from the surface.

Raises

RuntimeError – When the landing thruster has already been activated.
RuntimeError – When the lander has already been able to land.

orient()¶

Returns the current time, position and velocity for the spacecraft/lander.

Returns

float – The current time after the initial landing sequence time, in seconds.
1-D numpy.ndarray – Array of shape (3,) containing the current position in meters relative to the planet center.
1-D numpy.ndarray – Array of shape (3,) containing the current velocity in meters per second relative to the planet center.

take_picture(filename='landing_picture.xml')¶

Generates a picture viewable in MCAst, with framing decided by the current spacecraft/lander camera orientation.

Parameters: filename (str, optional) – Name of the XML file to generate inside the data directory. Default is “landing_picture.xml”.

start_video()¶

Starts recording what the spacecraft/lander camera sees.

Raises: RuntimeError – When called while video mode is active.

finish_video(filename='landing_video.xml', number_of_frames=1000, radial_camera_offset=100000.0)¶

Ends the recording and generates a corresponding video viewable in MCAst.

Parameters

filename (str, optional) – Name of the XML file to generate inside the data directory. Default is “landing_video.xml”.
number_of_frames (int, optional) – The number of video frames to generate. Default is 1000, but must be at least 100.
radial_camera_offset (float, optional) – The distance from the planet surface to offset the camera in order to avoid clipping during landing, in meters. Default is 10^5 meters.

Raises

RuntimeError – When called while video mode is not active.

look_in_fixed_direction(polar_angle=1.5707963267948966, azimuth_angle=0)¶

Orients the camera in a fixed direction specified by the given spherical angles.

Parameters

polar_angle (float, optional) – The polar angle to use for the camera direction. Default is pi/2. Must be in the range [0, pi].
azimuth_angle (float, optional) – The azimuthal angle to use for the camera direction. Default is 0.

look_in_direction_of_planet(planet_idx=None, relative_polar_angle=0, relative_azimuth_angle=0)¶

Makes the camera point towards a given angle relative to the direction of the planet.

Parameters

planet_idx (int, optional) – The index of the planet to track. By default the planet being landed on is used.
relative_polar_angle (float, optional) – The polar angle to offset the camera with relative to the direction towards the planet. Default is 0. Must be in the range [0, pi].
relative_azimuth_angle (float, optional) – The azimuthal angle to offset the camera with relative to the direction towards the planet. Default is 0.

look_in_direction_of_motion(relative_polar_angle=0, relative_azimuth_angle=0)¶

Makes the camera point towards a given angle relative to the direction of motion.

Parameters

relative_polar_angle (float, optional) – The polar angle to offset the camera with relative to the direction of motion. Default is 0. Must be in the range [0, pi].
relative_azimuth_angle (float, optional) – The azimuthal angle to offset the camera with relative to the direction of motion. Default is 0.

set_camera_up_vector(up_x, up_y, up_z)¶

Specifies the up-vector to use for the camera.

Parameters

up_x (float) – The x-component of the camera up-vector.
up_y (float) – The y-component of the camera up-vector.
up_z (float) – The z-component of the camera up-vector.

restart()¶

Resets the spacecraft and system to the state at the beginning of the landing sequence.

Note

If a new interplanetary travel destination has been recorded since the landing sequence began, the new destination state will be used as initial condition.

Also be aware that any recorded landing site coordinates will be cleared.

Raises: RuntimeError – When called while video recording is active.