Space
A key example of this is the T510 multiple anode manganese dioxide tantalum chip capacitor from Kemet. In the standard level of reliability, there are 37 values of the T510 capacitor listed. The voltage ranges from 4V to 50V with capacitance values from 22µF to
some technologies have shown advances. Oscillators, fuses and switches have all seen recent developments. The use of higher voltages can affect the reliability of satellite performance. The power systems in satellites have previously used
The fuses provide minimum and maximum
clear-times at overload currents regardless of vacuum conditions and eliminate the risk of out-gassing to avoid the de-rating factors covered by MIL-STD-975. Backed by funding from the European
Space Agency (ESA), Exxelia has developed a ferrite-based, Y-shaped switch which enables an antenna to be reconfigured, on-the-fly, in space. The ferrites enable the satellite to use a narrow spot-beam for beam-hopping across a range of smaller targets within the same territory. The operator controls the satellite so that higher bandwidth is delivered to certain locations. This targeted communication supports an increased capacity.
A hi-rel supply chain Voltage and capacitance ranges reduce as reliability increases
1000µF. For the automotive-grade version which complies to the AEC-Q200 standard, the number of versions drops to 24 over the same voltage and capacitance ranges. But there is a significant drop for the High Reliability Alternative (HRA) space-grade version of the T510, which has just four values with voltages from 4V to 10V and capacitance from 330µF to 1000µF. Specialist support at the early stage of the design can help the designer to ensure that the design uses parts which can be moved smoothly from BB to FM.
Screening for reliability Some component manufacturers, which have a definite focus on the space market, give designers the option of screening components to meet higher levels of reliability. The New Space Electronics programme
from TT Electronics offers 15 different tests for screening discrete and Multi-Chip Arrays (MCA). These tests cover the option of having a stabilising bake and pre-cap inspection, to component validation and group testing. There are also options to have residual gas analysis, radiography, Total Irradiated Dose (TID) and Single Event Upset (SEU) testing. For passives, Exxelia supports reliability by having 50 series of space-qualified components on the ESCC Qualified Parts List (QPL). This list covers film capacitors, magnetics and electromechanical filters which can be used in the satellite platform, payload or launcher. In fact, film capacitors from Exxelia were on the NASA InSight probe which landed on Mars from the rover Perseverance.
Emerging trends
Although the number of components which are listed on the QPL or EPPL is relatively low,
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It is not just the parts which need to deliver space-grade reliability, it is the whole supply chain which must provide confidence as well as traceability. The installation by Euroquartz of a Class 7 cleanroom in the UK enables its in-house manufactured surface-mount oscillators to
successful resolution of any issue which may affect the performance or reliability of the part.
Since 1985, Charcroft has maintained an archive of every CofC that has been received from a component manufacturer. The archive started with hardcopies of the CoCs and is now a fully digital archive with a scan of each CofC. A flag on the OMNIS computer system denotes which CofC or release is required with each shipment which is sent to an OEM or CEM. These documents can be used to recall batch numbers and manufacturing dates at any time in the future.
From COTS to QPL and beyond The trade-off needed to deliver high reliability at reduced cost demands specialist knowledge and skills from the designers of small satellites. The ability to complete this trade-off also demands the same level of knowledge and support from the supply chain.
Designers have the option of starting the design with components which are
The UK-based Euroquartz cleanroom is free from ITAR regulations
fuses which comply to MIL-PRF-23419/8 to protect circuits which operate on voltages from 28V to 50V DC. The trend now is to use voltage levels above the limit of 135V DC which can be protected by a standard high- reliability solid-body fuse. For these higher voltages, the solid body, current limiting fuses from AEM Inc., are on the ESCC QPL and have been added to the European Preferred Parts List (EPPL).
deliver reliability without being governed by the International Traffic in Arms Regulations (ITAR) regulations. ITAR regulates the export of certain US-manufactured products. The traceability of space-grade and other components is also critical throughout the supply chain. If a Certificate of Conformity and Certificate of Compliance is not retained by the OEM or CEM, full traceability can be lost. This can compromise the
manufactured to withstand industrial or automotive conditions. There is also the option of applying additional testing to increase the reliability offered by each component. These options mean that reliability can be extended from COTS to QPL and beyond as the satellite industry looks set to reach a new peak of launches in 2025.
www.charcroft.com Components in Electronics October 2021 15
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