11 Application of Low-Power Pulse Plasma Thrusters in Thrust Units …
147
11.4 Attitude Control and Angular Stabilization
The second task that can be assigned to EPS of SSC is the attitude control and angular
stabilization of the spacecraft. The reactive, flywheel, and gyro-force systems for
the spacecraft attitude control are known, while there is a tendency to gradually
abandon the use of reactive systems that require the consumption of propellant [10].
The peculiarity of the flywheel and gyro-force attitude control systems is that they
require periodic dumping of the accumulated kinematic momentum, which requires
an additional system for unloading the attitude control system, which, in turn, can
be reactive, magnetic (using the Earth’s magnetic field) and, less often, gravitational
or aerodynamic. Currently, for low-orbit SSC, the most widely used are the flywheel
and gyro-force attitude control systems in combination with a magnetic dumping
system. Such attitude control systems do not require the consumption of propellant
to control SSC motion relative to its center of mass. The problems associated with
increased consumption of electric power and an additional mass of electromechanical attitude control systems have been successfully solved. An electromechanical
attitude control system based on flywheels with magnetic unloading was applied
even on such a lightweight scientific SSC as “Chibis-M” weighing 42 kg only [11].
Nevertheless, reactive attitude control systems comprising pulsed plasma thrusters
are also characterized by low mass and extremely low propellant consumption. The
first use of APPT for the system of solar panel attitude control took place at the end
of 1964 on the spacecraft “Zond-2”, developed by the RSC “Energia” [12].
When very precise SSC attitude control is required, for example, for remote Earth
sensing satellites, the reactive attitude control systems based on the pulsed electric
propulsion with a very small single thrust pulse are still beyond the competition. In
particular, a reactive attitude control system with APPT was used on the remotesensing satellite “EO-1” with an active lifetime of about 10 years [13]. In that case,
the reactive attitude control system operated together with the electromechanical
attitude control system, providing precise pointing of optical surveillance devices.
The total pulse of a single EPS module required for that was just 0.46 kN s.
11.5 Available Family of Pulsed Plasma Thrusters
and Their Rational Application Areas
Currently, a number of electric propulsion systems based APPT with discharge
energy from 8 to 155 J are developed at the RIAME MAI, which is shown in
Fig. 11.5 [7]. All propulsion systems of the APPT series are intended mainly for
correcting and maintaining the orbit of low-orbit SSC. The most advanced of them
are the following: APPT-45–2, APPT-155, and APPT-95 EPS. They passed the full
range of ground experimental testing (in the case of APPT-95, with the exception
of lifetime tests). APPT-45–2-based EPS designed for the scientific small spacecraft
“MKA-FKI PN2” was launched into low Earth orbit in 2014. APPT-155-based EPS
147
11.4 Attitude Control and Angular Stabilization
The second task that can be assigned to EPS of SSC is the attitude control and angular
stabilization of the spacecraft. The reactive, flywheel, and gyro-force systems for
the spacecraft attitude control are known, while there is a tendency to gradually
abandon the use of reactive systems that require the consumption of propellant [10].
The peculiarity of the flywheel and gyro-force attitude control systems is that they
require periodic dumping of the accumulated kinematic momentum, which requires
an additional system for unloading the attitude control system, which, in turn, can
be reactive, magnetic (using the Earth’s magnetic field) and, less often, gravitational
or aerodynamic. Currently, for low-orbit SSC, the most widely used are the flywheel
and gyro-force attitude control systems in combination with a magnetic dumping
system. Such attitude control systems do not require the consumption of propellant
to control SSC motion relative to its center of mass. The problems associated with
increased consumption of electric power and an additional mass of electromechanical attitude control systems have been successfully solved. An electromechanical
attitude control system based on flywheels with magnetic unloading was applied
even on such a lightweight scientific SSC as “Chibis-M” weighing 42 kg only [11].
Nevertheless, reactive attitude control systems comprising pulsed plasma thrusters
are also characterized by low mass and extremely low propellant consumption. The
first use of APPT for the system of solar panel attitude control took place at the end
of 1964 on the spacecraft “Zond-2”, developed by the RSC “Energia” [12].
When very precise SSC attitude control is required, for example, for remote Earth
sensing satellites, the reactive attitude control systems based on the pulsed electric
propulsion with a very small single thrust pulse are still beyond the competition. In
particular, a reactive attitude control system with APPT was used on the remotesensing satellite “EO-1” with an active lifetime of about 10 years [13]. In that case,
the reactive attitude control system operated together with the electromechanical
attitude control system, providing precise pointing of optical surveillance devices.
The total pulse of a single EPS module required for that was just 0.46 kN s.
11.5 Available Family of Pulsed Plasma Thrusters
and Their Rational Application Areas
Currently, a number of electric propulsion systems based APPT with discharge
energy from 8 to 155 J are developed at the RIAME MAI, which is shown in
Fig. 11.5 [7]. All propulsion systems of the APPT series are intended mainly for
correcting and maintaining the orbit of low-orbit SSC. The most advanced of them
are the following: APPT-45–2, APPT-155, and APPT-95 EPS. They passed the full
range of ground experimental testing (in the case of APPT-95, with the exception
of lifetime tests). APPT-45–2-based EPS designed for the scientific small spacecraft
“MKA-FKI PN2” was launched into low Earth orbit in 2014. APPT-155-based EPS