Update S/C mass and extForceTorque force

[schaubh]

Hi Basilisk users!
I’m struggling with a Basilisk simulation that exhibits several memory leaks, causing the RAM to reach too high values.
I modelled a spacecraft equipped with an extForceTorque object to simulate a low-thrust thruster. I set up the simulation to be executed in multiple steps, because at each step I want to impose a different force value.
Right now, I’m updating the force value directly by changing extForce_B (extForceTorqueObject.extForce_B = [[new_fx], [new_fy], [new_fz]]) before each simulation step. I’m also updating the mass of the spacecraft by computing the mass loss and changing the value of mHub (scObject.hub.mHub = new_mass).
However, this causes several memory leaks problems.
Is there a proper way to manage the messages to set a new force value for the extForceTorque object and to update the mass of the s/c at each simulation step without relying on a thruster object?

Thank you for your help!

[schaubh]

Hi Federica,

Mass depletion arising from thruster use is handled by the FuelTank class in the Basilisk simulation modules. This class needs to be connected to a dynamic effector (namely, a thruster) for the overall mass update to be considered.

As far as I know, there is currently no low-thrust engine model in Basilisk. The thruster model you can find in Basilisk these days is tailored for high-thrust, chemical propulsion. The steady-state thrust output by this model is defined in a configuration message that I would refrain from making time-varying.

I think the best way to go would be to make your own low-thrust thruster module, following the original basilisk thruster class as a template from which you would remove a lot of unnecessary aspects. This way you could also leverage the FuelTank class.

[schaubh]

Federicafederica.fp96@gmail.com
Mar 29, 2022, 3:58:03 AM
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Thank you for your answer!
For sure implementing a custom Thruster module+FuelTank will be the best way and I'm working on it.

However, to perform some preliminar tests, I'm wondering if it is possible to use the extForceTorque object. I'm able to update the istantaneous value of the applied force through appropriate input messages that I change at each simulation step. But I can't find a way to do the same for the S/C mass.
As far as you know, is there a way to act directly on the S/C mass and modify it through appropriate messages without implementing a Thruster and FuelTank object?