Projectile

The Projectile class contains information about the populations of projectiles used to scale between crater and projectile sizes.

To define a projectile, a Target must be created first. If you’re unsure how to define a target, see the Target documentation for guidance.

Creating a Projectile

Example 1: Using a target from the catalogue

In [1]: from cratermaker import Projectile

In [2]: from cratermaker import Target

# First define the target
In [3]: target = Target.maker("Moon")

#The projectile is determined based on the target by default
In [4]: projectile = Projectile.maker(target=target)

# Print projectile properties
In [5]: print(f"cratermaker projectile: {projectile}")
cratermaker projectile: <AsteroidProjectiles>
Sample from distributions: True
Mean Velocity: 22.10 km/s
Density: 2250.0 kg/m³
Target: Moon

If no projectile parameters are specified, Cratermaker will use a default asteroid population suitable for the specified target.

Example 2: Creating a custom projectile

You can specify projectile properties manually using keyword arguments.

In [6]: projectile_userdefined = Projectile.maker(
   ...:     projectile="generic",
   ...:     sample=False,
   ...:     velocity=22000.0,   # meters/second
   ...:     angle=45.0,         # degrees
   ...:     direction=90.0,
   ...:     density=3000.0,     # kg/m³
   ...:     target="Moon"
   ...: )
   ...: 

In [7]: print("Projectile defined by user:", projectile_userdefined)
Projectile defined by user: <GenericProjectiles>
Velocity: 22.00 km/s
Angle: 45.0°
Direction: 90.0°
Density: 3000.0 kg/m³

In this case, the user specifies the projectile velocity, impact angle, trajectory direction, and material density. The target is still required to complete the projectile’s initialization.

More Projectile examples

See more examples at Projectiles and Scaling