General Question Delta Glider engine parameters for GMAT ChemicalThruster configuration

[ghrasko]

Hi,

I am checking how could I combine mission planning in GMAT with Orbiter. As a simple example, I would like to plan a Hohmann transfer from LEO to a higher orbit. I planned the scenarion in GMAT both with ImpulsiveBurn and FiniteBurn steps. The more realistic is the FiniteBurn based scenarion of course. But for that I should define the thruster parameters: thrust (N) and ISP (sec) to calculate the neccessary full thrust burn duration.

Is it possible to get these data for the Delta Glider and is it feasible to plan a Hohhmann transfer based on this? I know that I could use the MFD for this, but I am checking how to work together with Orbiter and GMAT.

Gábor

 

[ghrasko]

Well, I guess, I found it in the doc:

Thrust: 2 x 1.6·10^5 N (main engines)
Isp: 4·104 m/s (fuel-specific impulse in vacuum)

Anyhow, has anyone calculated such values with GMAT and checked it in Orbiter?

If I understand correctly, this ISP is in m/sec and in GMAT it is in sec. If I call the orbiter versnio as ve (exhaust gas speed), then:

Isp = ve / g0 = 4 x 10^4 / 9.80665 = 4079 sec

Ref: https://en.wikipedia.org/wiki/Specific_impulse#Specific_impulse_in_seconds

 

[francisdrake]

These data are included as an example in OrbiterSDK\DeltaGlider\DeltaGlider.h

const double EMPTY_MASS = 11000.0; // standard configuration
const double EMPTY_MASS_SC = 13000.0; // ramjet configuration
// DG mass w/o fuel

const double PSNGR_MASS = 85.0;
// mass per passenger (including life support system)

const double TANK1_CAPACITY = 10400.0;
const double TANK2_CAPACITY = 2500.0;
// Main fuel tank capacities [kg] (can be split between rocket
// fuel and scramjet fuel)

const double RCS_FUEL_CAPACITY = 600.0;
// Max fuel capacity: RCS tank [kg]

const double MAX_MAIN_THRUST[2] = {2.0e5, 1.6e5};
// Main engine max vacuum thrust [N] per engine. (x2 for total)

const double MAX_RETRO_THRUST = 3.4e4;
// Retro engine max vacuum thrust [N] per engine. (x2 for total)

const double MAX_HOVER_THRUST[2] = {1.4e5, 1.1e5};
// Hover engine max vacuum thrust [N] (x2 for total)

const double MAX_RCS_THRUST = 2.5e3;
// Attitude control system max thrust [N] per engine.

const double ISP = 4e4;
// Vacuum Isp (fuel-specific impulse) for all thrusters [m/s]