COBEM99

S8 Engenharia Aeroespacial

Title:

SISTEMA PROPULSIVO PARA A PLATAFORMA SUB-ORBITAL

Summary :

THE PROPULSION SUBSYTEM OF THE SUB-ORBITAL PLATFORM ABSTRACT. THIS PAPER DESCRIBES THE DESIGN, FABRICATION AND OPERATION OF THE PROPULSION SUBSYSTEM USED FOR ATTITUDE CONTROL OF THE SUB-ORBITAL PLATFORM (PSO). THE PSO IS AN EXPERIMENTAL PLATFORM WITH A MASS OF APPROXIMATELY 110 KG, WHICH IS LAUNCHED BY A TWO STAGE SOUNDING ROCKET, THE SONDA III. AT THE END OF THE PROPULSIVE PHASE, THE PLATFORM IS SEPARATED FROM THE LAST STAGE OF THE ROCKET, WITH AN ANGULAR SPEED OF 130 RPM AND FOLLOWS A PARABOLIC TRAJECTORY WITH APOGEE OF 400 KM. STABILIZATION OF THE PLATFORM BEGINS IMMEDIATELY AFTER SEPARATION. DURING THIS PHASE THE ONBOARD COMPUTER, USING A PRE-LOADED CONTROL STRATEGY, COMMANDS THE FIRING OF THE THRUSTERS TO OBTAIN THE TORQUES REQUIRED TO REDUCE THE ROTATIONAL MOVEMENT OF THE PLATFORM. THE ANGULAR VELOCITY IN THE THREE AXES, AT THE END OF THE STABILIZATION PHASE MUST BE LESS THAN 0.033 RPM AND THE ACCELERATION IN EVERY LOCATION ON THE PLATFORM MUST BE LESS THAN 10-6 G0, CHARACTERIZING A MICRO-GRAVITY ENVIRONMENT. THE STABILIZATION PHASE LASTS APPROXIMATELY 3 MINUTES, AFTER WHICH THE PLATFORM FOLLOWS A PARABOLIC FLIGHT PATH FOR APPROXIMATELY 7 MINUTES, DURING WHICH MICRO-GRAVITY EXPERIMENTS MAY BE RUN. THE PROPULSION SUBSYSTEM COMPRISES A PROPELLANT TANK WITH CAPACITY OF 900 ML OF PROPELLANT, A PRESSURE TRANSDUCER, TWO FILL AND DRAIN VALVES AND FOUR HYDRAZINE MONOPROPELLANT THRUSTERS WITH NOMINAL THRUST OF 2 N. THE PROPELLANT TANK HAS A CYLINDRICAL BODY WITH ELLIPTICAL CAP ENDS. THE PRESSURIZING AGENT IS GASEOUS AND IT IS SEPARATED FROM THE PROPELLANT BY A FREE PISTON INSIDE THE CYLINDRICAL BODY. THE SYSTEM OPERATES IN BLOWDOWN WITH RATIO OF 4:1. KEYWORDS: PROPULSIVE SYSTEM, MICRO-GRAVITY, CONTROL SYSTEM

Author :

Hinckel, José NIvaldo
Varotto, Sebastão Eduardo C.

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