cmech

README

cmech

A simple celestial mechanics package in golang

Body

A struct which models a celestial body in the solar system. Mass in kg, state vector in cartesian coordinates (km-s).

func (body *Body) Update(other *Body, timestep float64)

Updates the state vector of a pair of Bodies based on gravitational forces for a single timestep.

getsv

Uses the JPL Horizons telnet server to get a mass and state vector for a celestial body. Includes a command line demo application.

Documentation

Index

• Constants
• type Body
  • func (body *Body) Dist(other *Body) float64
  • func (body *Body) Update(other *Body, timestep float64)
• type CMSystem

Constants

const G float64 = 6.674e-20 // km**3 / kg-s**2

gravitational constant

Types

type Body

type Body struct {
	Name string
	X    float64
	Y    float64
	Z    float64
	Vx   float64
	Vy   float64
	Vz   float64
	T    float64 // thrust
	TVx  float64 // thrust direction (unit vector)
	TVy  float64
	TVz  float64
	Mass float64
}

celestial body km, sec, kg

func (*Body) Dist

func (body *Body) Dist(other *Body) float64

compute the Euclidian distance between two bodies

func (*Body) Update

func (body *Body) Update(other *Body, timestep float64)

update state of body and other based on pairwise interaction G m1 m2 / r ** 2 meters, seconds

type CMSystem

type CMSystem []*Body

system of Bodys