European Space Agency

SAAF A configurable Solar Array Ancillary Functions for telecoms AIT


The activities under the SAAF project address the ancillary functionalities and autotest capabilities that coupled with a power producing SAS (Solar Array Simulator) would provide full simulation and verification of the power and dynamic aspects of a spacecraft Solar Array (SA), see figure below:

SAAF Conceptual Diagram

 The basic functionality of SAAF can be decomposed into three principal blocks:

  • Autotest.
  • SA Initial Deployment.
  • SA Through-life Simulation.


Key challenge was to keep the design generic enough to satisfy the needs of both telecom customers in Europe and USA.


The product provides a major reduction in validation time for telecom  customer during AIV and re-configuration of facility for different S/C.



The Autotest capability provides satellite integrators with an automated tool for verifying the performance and safety of the SAS equipment and harness before it is connected to the spacecraft. It provides the following major features:

  • Assurance of Spacecraft Protection:
    • Automated verification of the correct operation of OVP, OCP and UVP of each SAS and SLP unit.
  • SAS Accuracy Testing:
    • Automated verification of the output accuracy of the SAS units.
    • Automated (or limited user intervention) calibration of the SAS units.
  • SAS Endurance Testing:
    • Automated verification of SAS unit long-term stability at full power.

SA Initial Deployment

The SA Initial Deployment simulation capability provides satellite integrators with the ancillary functions related to the initial deployment of the spacecraft SA, namely:

  • Pyro Simulation:
    • Automated simulation and verification of the spacecraft pyrotechnics firing pulses for full Pyro characteristic verification to and from the spacecraft.
  • Hinge Simulation:
    • Automated simulation and verification of the spacecraft hinge feedback signals for indication of successful deployment. 

SA Through-life Simulation

The SA Through-life Simulation capability provides satellite integrators with emulation of the SA sensors and actuators (aside from provision of power itself) which operate during the nominal power harvesting phases of the mission:

  • Thermistor Simulation:
    • Automated simulation of temperature sensor outputs distributed across SA sections.
  • Solar Array Drive Mechanism (SADM):
    • Automated simulation and verification of the Solar Array Drive Mechanism load characteristics and feedback to the spacecraft. Automated reaction to the control signal from the spacecraft with the appropriated load and provision of the correct angular position feedback to the spacecraft.
  • Strain-gauge Simulation:
    • Automated simulation and verification of the strain-gauge sensor outputs towards the spacecraft, different scenarios provided in terms of sensor type and the effects of tension and compression on the sensor output.


As described in Contract and CCN1. 

Current status

Current status is completed.

Status date

Wednesday, December 2, 2020 - 09:38