There is zero pressure in space, and the components manufactured under atmospheric pressure may behave differently under such no-pressure conditions.
Outgassing is the phenomenon of releasing gases by non-metallic materials.
Several techniques such as potting, external shielding, and insulating substrate usage for space-grade ICs are employed for preventing failure in electronics utilized in space missions.
There is rapid (and exciting!) progress in space technology, and these advancements are contributing to the growth of space applications. Electronic circuits are imperative in any space application – they play a significant role in building efficient and reliable space systems.
Unattended challenges in electronic circuits in space applications are expensive to fix. Space is a harsh environment with numerous challenges for electronic circuits. Component failures, outgassing, and mechanical mounting issues are just some of the challenges faced by electronic circuits in space applications. In this article, we will explore how electronics affect the reliability of space applications and a few ways to mitigate these issues.
Space Is a Harsh Place for Electronic Circuits
The environment where electronic components operate is very important for their reliability. As the temperature, pressure, and other ambient conditions change, the behavior of the materials change as well, and the component may even fail under extremely harsh conditions.
If you look at the datasheets for most electronic components, you may see a grade of applications such as commercial, military, aerospace, automotive, etc. Grades are specified for their use in particular fields, meaning those components will be able to withstand the extreme conditions specified in the datasheet.
Here are some of the space conditions that pose challenges for electronic circuits:
Pressure - There is zero pressure in space and components manufactured under atmospheric pressure may behave differently under such no-pressure conditions.
Ion and particle presence - In the space application for low earth orbits, UV radiation causes molecular degradation of helium, oxygen, nitrogen, etc. The atomic versions of these elements initiate corrosion and erosion of materials. The ions and free electrons in space can cause arching, which may affect sensitive electronic components.
UV degradation - UV degradation changes the composition of materials and can even remove oxygen from materials, thereby affecting the performance of the components.
Radiation - The free-particle radiation environment can introduce single-event glitches that may challenge the operation of sensors and controls in electronic circuits.
Extreme temperature and thermal cycles - Extreme hot and cold temperatures and thermal cycles impose mechanical stress on electronic components, especially ICs and their packages.
Apart from the conditions in space, vibration during the launch of a space system is the main reason for the failure of space electronic circuits.
Common Challenges for Electronic Circuits in Space Applications
Circuit Board Damage
Space applications are subjected to vibrations at the launching stage, separation stage, etc. The shocks and vibrations generated at any of these stages are strong enough to damage the circuit boards. The shocks and vibrations may short electrical components.
The jerking of the circuits may cause loose connections or connector failures. The loss of data transfer or control due to loose connections or intermittent connections can be disastrous in space applications. Another mechanical vibration-induced failure challenging space electronic applications is the resonance in electronic components, which should be addressed to ensure reliable missions.
One of the major concerns of electronic circuit applications in space is outgassing. Outgassing is the phenomenon of non-metallic materials releasing gases. Thermal paste, plastics, glues, or PCB materials can all outgas. The vapor or air released from such materials can deposit on other components and affect their performance. The vapor release from materials can even result in short circuits between leads, connectors, components, etc.
Reduced Life and Operational Functionality
The temperature can hit extreme values in space, and this adversely affects electronic circuits. The wide variation of temperatures may shorten a component's lifetime and significantly limit its operational functionality. When commercial off-the-shelf components are subjected to temperatures above or below the allowable range, it can lead to failure.
Materials such as tin, cadmium, zinc, etc. in electronic components and circuits grow whiskers in the vacuum of space. These whiskers are crystalline and electrically conductive and can lead to short circuits.
Mitigating Electronic Circuit Challenges in Space Applications
Space missions are already expensive; repairing a failed system is not economical or practical. It is important to ensure the challenges faced by electronic circuits in space applications are addressed before a mission is launched. Several techniques are employed for protecting the electronics utilized in space missions, including potting, external shielding, and insulating substrate usage for space-grade ICs.
Cadence’s suite of design and analysis tools can help you in designing space application electronic circuits. Cadence tools help by simulating, analyzing, and modeling the sensitive parameters of your design under different conditions.
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