$LastChangedDate: 27-Juil-2011 $

# CL_3b_environment

Structure creation for the 3-body problem functions

## Calling Sequence

       env = CL_3b_environment(bodies,Lpoint)

## Description

- Creates a structure to be used by other "3b" functions.

  This structure contains the necessary information about a specific libration point in a specific system.

  At the moment, only (Earth + Moon), (Sun + barycenter of Earth-Moon) and (Sun + Jupiter) systems are included, and only the colinear libration points (L1, L2 and L3) are defined.

- Description of output structure fields:

  - bodies: (string) System of primaries ('S-EM', 'E-M' or 'S-J')

  - Lpoint: (string) Libration point ('L1', 'L2' or 'L3')

  - gammal: Adimensional distance between the libration point and the closest primary (m1-L1 or m1-L2 or m2-L3)

  - MU: constant mu: Ratio of the mass of the biggest primary to the mass of the smallest primary (mu1/mu2)

  - omega_init: Used for internal computations.Theoretical pulsation of in-plane motion for orbits around the libration point

  - k: Used for internal computations

  - gl: Distance from the center of mass of the primaries to the libration point (G-L1 or G-L2 or G-L3)

  - pas: Integration step

  - OMEGA: Pulsation (rad/s) of the primaries around their center of mass G. Used to "adimensionalyse" time (1 year => 365.25*24*3600*OMEGA)

  - D: Distance (m) between the primaries. Used to "adimensionalyse" distances and velocities

  - c2: Used for internal computations

  - nu: Used for internal computations

  - invM: Used for internal computations

  - ESCAPEDIR: Used for internal computations

  - ESCAPEDIRNORM: Used for internal computations

- Notes:

  - The stacksize is changed to 5e7 in order to perform the Manifold computations.

( Last updated: 2010-09-20 )

## Parameters

bodies:

  (string) Body system: 'S-EM', 'E-M' or 'S-J'

Lpoint:

  (string) Type of libration point. It can be 'L1', 'L2' or 'L3'

env:

  Resulting structure.

## See also

- CL_3b_halo

- CL_3b_lissajous

- CL_3b_manifolds

## Authors

- CNES - DCT/SB

## Examples

    envL1 = CL_3b_environment('S-EM','L1')