$LastChangedDate: 27-Juil-2011 $

# CL_cw_contPropa

Continuous thrust trajectory

## Calling Sequence

       [t,rel_pos_vel]=CL_cw_contPropa(t_ini,rel_pos_vel_ini,gama_diff,...
       alt,t_end,delta_t,[ballistic_coef_chaser,ballistic_coef_target,er,mu])

## Description

- Computes the position and velocity vector of a chaser relative to a target when the motion of the chaser is affected by continuous thrust.

  The output argument rel_pos_vel contains the positions and velocities of the chaser relative to the target in the target's LVLH reference frame at the times t.

  If no ballistic coefficients are given, acceleration due to drag is not taken into account.

## Parameters

t_ini:

  Initial time [seconds] (1x1)

rel_pos_vel_ini:

  Initial position and velocity vector of the chaser relative to the target in the target's LVLH frame [X;Y;Z;Vx;Vy;Vz] [m;m/s] (6x1)

gamma_diff:

  Continuous thrust differential acceleration [ax, ay, az] [m/s**2] (3xM)

alt:

  Altitude of target [m]

t_end:

  Final time [seconds] (1x1)

delta_t:

  (optional) Time step [s] (default is 100)

ballistic_coef_chaser:

  (optional) Ballistic coefficient of chaser : S*cx/m S=equivalent drag surface, cx = drag coefficient, m = mass [m^2/kg] (default is 0)

ballistic_coef_target:

  (optional) Ballistic coefficient of target : S*cx/m S=equivalent drag surface, cx = drag coefficient, m = mass [m^2/kg] (default is 0)

er:

  (optional) Equatorial radius [m] (default is %CL_eqRad)

mu:

  (optional) Gravitational constant [m^3/s^2] (default value is %CL_mu)

t:

  Computation times [seconds] (1xN)

rel_pos_vel:

  Position and velocity vectors of chaser in target's LVLH frame at corresponding times [X;Y;Z;Vx;Vy;Vz] (6xN)

## Authors

- CNES - DCT/SB

## See also

- CL_cw_impulPropa

- CL_cw_diffDrag

- CL_cw_Mmatrix

- CL_cw_Nmatrix

## Bibliography

- 1) Mecanique spatiale, CNES - Cepadues 1995, Tome II

## Examples

    t_ini = 11550.677;
    rel_pos_vel_ini = [-250; 0. ; 0 ; -3e-6 ; 0. ; 3e-6];
    gama_diff = [0. ; 0. ; 0.0003238];
    alt = 450.e3;
    ballistic_coef_chaser = 100 * 1 / 20.e3;
    ballistic_coef_target = 200 * 1 / 400.e3;
    t_end = 4*3600; // 4 hours of ballistic propagation
    delta_t = 100; // 100 seconds time step
    [t,rel_pos_vel] = CL_cw_contPropa(t_ini, ..
    rel_pos_vel_ini,gama_diff,alt,t_end,delta_t, ..
    ballistic_coef_chaser,ballistic_coef_target)