Speaker
Description
Summary
Electronic components in an orbiting satellite will be exposed to a total ionizing dose (TID) commensurate with its mission trajectory. Solar particles, electrons/protons trapped in the Van Allen belts and galactic cosmic rays (GCRs) are the main sources. TID due to cosmic electrons and protons can cause device failures. Such detrimental events have a cumulative effects during the whole mission lifetime of the components and, with well-established techniques, it is possible to estimate when the tested component(s) will fail during under relevant operating conditions.
Power Amplifiers (PAs) are chosen as test subjects here as they are key configuration items in any communication satellite. Downlink signals are boosted by PAs in order to compensate for atmospheric path losses. The two primary types of PAs in the market today are: Solid-State Power Amplifiers (SSPAs) and Travelling Wave Tube Amplifiers (TWTAs) [1]. They are also critical elements in space-borne phased-array applications. GaAs-based SSPAs are widely used in satellite systems today with GaN-based solutions becomes as attractive alternatives due to their inherent high power density capabilities [2].
Accompanying the efforts of manufacturing domestic satellite payload components is a need to carry out standard radiation tests to qualify the end equipment for space. Reliability of these components within space environment can only be guaranteed by ground-based qualification through radiation tests together with other widely used environmental tests under varying thermal, vacuum, vibration and shock conditions. Although, the latter set of tests can be performed in-house, there is an urgent need to develop capability to carry out the radiation tests locally so as to expedite the qualification of satellite subsystems or components.
Within easy reach of ASELSAN, there is a test center facility in Ankara; Sarayköy Nuclear Research and Training Center (SANAEM), operated by the Turkish Atomic Energy Agency (TAEK). As dictated by a tight schedule, the construction of the test setup at SANAEM, and the design and manufacturing of the modules were carried out simultaneously to reduce schedule risks. TID tests will be performed using the Co-60 source located at the TAEK SANAEM Gamma Irradiation facility. The source has an activity level of 300 kCi and can deliver a dose rate higher than 30 kRad(Si)/h, which is in compliance with the ESA 22900 standard high dose rate recommendation. A new chamber was designed and built in order to attenuate and deliver the necessary dose rate [3].
Results obtained from tests as described in ECS22900 from the European Space Agency (ESA) [4] to monitor the TID effects and exhibited sensitivities of SSPAs are presented here. Next in line are other critical components like attenuators, phase shifters, etc., and relevant results will be shared during the conference.
REFERENCES
[1] R. Strauss, Orbital Performance of Communication Satellite Microwave Power Amplifiers (MPAs),”International Journal of Satellite Communications, vol. 11, 1993, pp. 279-285.
[2] M. Kaliski, ““Evaluation of the Net Steps in Satellite High Power Amplifier Technology: Flexible TWTAs and GaN SSPAs”,” IEEE International Vacuum Electronics Conference, April, 2009.
[3] R. Uzel et. al. Cost Effective Total Ionizing Dose Tests of Solid State Power Amplifiers, Reinventing Space Conference 2015, BIS-2015-24, Oxford, UK
[4] ESA/SCC Basic Specification No.22900 “Total-Dose Steady State Irradiation Test Method”
