$LastChangedDate: 27-Juil-2011 $

# CL_man_thrustDuration

Thrust duration as function of mass consumed

## Calling Sequence

       [output]=CL_man_thrustDuration(type_output,par1,par2,par3 [,g0])
       [dt]=CL_man_thrustDuration('dt',dm,F,isp,[g0])
       [dm]=CL_man_thrustDuration('dm',dt,F,isp,[g0])
       [F]=CL_man_thrustDuration('F',dt,dm,isp,[g0])
       [isp]=CL_man_thrustDuration('isp',dt,dm,F,[g0])

## Description

- The thrust duration can be computed as a function of mass consumed, thrust and propellant specific impulse by the following equation:

  Given 3 of the 4 variables that appear in the equation (thrust duration, mass consumed, thrust value and Isp), the function computes the 4th one.

  The output argument type_output defines the parameter to be computed. It can be among the following:

  - 'dt' : thrust duration.

  - 'dm' : mass consumed

  - 'F' : thrust value.

  - 'isp' : propellant specific impulse.

  Notes:

  - Input arguments are always in the same order: dt, dm, F, isp

  - The flow rate (mass consumed per unit of time) can be computed by : flow = dm./dt

## Parameters

type_output:

  String defining the parameter to be computed. It can be 'dt,'dm','F' or 'isp'. (1x1)

par1:

  First input parameter: dt, dm, F or isp [s kg N or s] (1xN)

par2:

  Second input parameter: dm, F or isp [kg N or s] (1xN)

par3:

  Third input parameter: F or isp [N or s] (1xN)

g0:

  (optional) value of gravity acceleration. [m/s^2] (default value is %CL_g0) (1x1)

output:

  Value of computed parameter: dt, dm, F or isp [s kg N or s] (1xN)

## Authors

- CNES - DCT/SB

## Bibliography

- 1) Orbital Mechanics for Engineering Students, H D Curtis, Equations 11.10, 11.12, 11.22, 11.30

- 2) Mecanique spatiale, CNES - Cepadues 1995, Tome I, section 4.8.6

## See also

- CL_man_consumption

## Examples

    // mass consumed in kg
    isp = 220; // seconds
    dv = 1; // m/s
    m = 180; // kg
    dm = CL_man_consumption('dm',dv,isp,m);

    // thrust duration in seconds
    F = 1 ; // N
    [dt] = CL_man_thrustDuration('dt',isp,F,dm)