Previous studies in radiation induced degradation in optocouplers at room temperature indicated that the most affected parameters were CTR and dark current. This fact is also applicable to high voltage (HV) optocoupler where the working voltage could go up to 10KV.
Microbolometers Focal Plane Arrays (FPA) are uncooled infrared arrays suitable for the detection in the 8-14μm spectral
range. Standard products show attractive performances and are available at low cost. They can be consistently used for
space missions on microsatellites. A microbolometers focal plane array (a 640x480 microbolometer array with a pitch of
25 μm) is foreseen to be used on the Mistigri mission proposed by CNES (French National Space Agency). The
scientific objectives of the mission are the monitoring of water conditions of agricultural crops and natural vegetation.
These objectives can be reached thanks to observations in the thermal infrared wavelength. Mistigri is now at an early
stage of development (preliminary definition study). CNES has started a technological evaluation on the
microbolometers array as a risk mitigation action. This technological evaluation plan includes radiation tests (ionizing
dose, displacement damage, and heavy ions), lifetest, thermal cycling and vibrations and shocks. At the same time we
have addressed fine performances of the microbolometers arrays in order to optimize instrument design and
The reliability of bipolar silicon-based phototransistors was investigated through evaluation tests for space
applications. First of all a preliminary evaluation program including thermal cycling, vibrations and shocks test, radiation
test and high-temperature operating life test was carried out to assess the overall quality of these phototransistors. During
life test abnormal fluctuations of phototransistors collector current measured under constant illumination have been
observed. In order to solve this problem, a failure analysis was conducted. Mobile charges located in the photobase
passivation layer were found to be at the origin of these fluctuations. Based on these results a new methodology for
device selection was proposed to achieve, despite to that issue, high reliability in operating conditions.
The goal of this study is to perform a complement of the existing Telcordia standard in order to assess the reliability of commercial optical microswitches in a space environment. A standard qualification (Telcordia / Bellcore) already exists for ground applications, but some topics (in particular radiation and in vacuo operation), which are a specificity of the space environment, are not covered. To this purpose, a specific test battery (γ-ray, neutrons, protons and in vacuo life tests) has been developed in order to assess the switch behavior in space environment and to achieve a complete evaluation of these optical microswitches for space applications. Little effect has been observed on such devices that may be considered as possible candidates for space applications, at least concerning the mission constraints detailed in this study.
Various circuits dedicated to high spectral purity signal transmission using fiber optics are presented. Three application types are investigated: signal transmission of ultra stable oscillators at 10 MHz, IF distribution at 874 MHz and microwave synthesized signals at 3.5 GHz. The receiver circuit is an optically synchronized oscillator, which provides a good signal conditioning far from the carrier while maintaining the high input signal quality close to the carrier