The famous tagline from the movie Alien noted, “In space, no one can hear you scream.” Back on earth, however, everyone will hear the screaming if a multimillion-dollar spacecraft fails due to problems with faulty components. That’s why it is critical that aerospace designers pick the right capacitors for space-based applications—and make sure to avoid counterfeit parts that can be subject to failure.
Electronics in aerospace applications
The related areas of space exploration and nuclear missiles were major factors driving the early development of the electronics industry and technology. NASA’s Apollo moon mission triggered the invention of integrated circuit (IC) technology, while the Minuteman missile program spurred the first mass production of ICs. Space travel is demanding on electronic components and systems. Challenges include extreme vibrations, wide temperature variations and airless vacuum conditions. Radiation is also a major concern, potentially causing failure or even the complete destruction of electronics.
Because of these issues, electronics for space must meet demanding specifications. As a result, the market for space-worthy components is limited to a small number of suppliers who have the capabilities to meet the standards.
Aerospace component breakdowns
Failures in space missions sometimes have been attributed to component breakdowns. The use of defective SRAM was proffered as one of many possible reasons for the downing of the Russian Phobos-Grunt space probe. The Phobos-Grunt, launched in 2011, was intended to make a round trip to one of the moons of Mars. However, the probe failed to rocket out of earth orbit and eventually crashed.
The director of the Russian space agency attributed the failure to counterfeit parts, which malfunctioned after being exposed to the radiation of cosmic rays.
A commission investigating the accident concluded that the Phobos-Grunt mission failure was the result of many factors, including poor quality control and lack of testing.
Aerospace counterfeit parts: Dangers & best practices
Counterfeit parts have been a growing challenge for the electronics business for many reasons, including the increasing number of Chinese players in the industry. Also, the large number of obsolete parts used in aging military aerospace programs makes the market a tempting target for counterfeit components.
To fight the onslaught of fakes, NASA helped form the SAE International G-19 Committee to develop practices designed to reduce risks related to counterfeit parts. NASA has instituted a range of counterfeit detection and avoidance procedures. The agency also has developed methods to assess suppliers’ capabilities and potential problems.
Electronic component counterfeits: How to validate
However, space contractors must take it upon themselves to implement a process to determine which fake devices are in the marketplace. This requires constant effort and reliable data sources to be aware of reports of fake devices in the market.
Companies also can engage in more extensive testing of electronic products. For example, NXP Semiconductors has released an USB Type-C solution designed to validate devices, including checking for counterfeit parts in power supplies.
MIL standards for aerospace
Contractors also must ensure they are procuring parts that comply with standards for performance and ruggedness in space. Among these standards is MIL-PRF-55365, which sets general requirements for tantalum dielectric, fixed-chip capacitors. These capacitors are primarily intended for use in thick and thin film hybrid circuits or surface-mount applications for filter, bypass, coupling, and other applications.
Another standard is MIL-STD-1580, which defines the requirements for destructive physical analysis of samples of parts. The standard sets requirements for analysis procedures and interpreting results.
Alternatively, there’s the European Space Components Coordination's (ESCC's) specification 3009, which covers various types of capacitors, including ceramic, tantalum and feedthrough. The specification includes ratings, physical and electrical characteristics, and test and inspection data.
Using aerospace electronics manufacturers
Aerospace contractors can ensure components are authentic and standards compliant by sourcing directly from suppliers or from authorized distributors. Some capacitor suppliers are offering devices that are specifically designated for space, aerospace and military applications.
For example, AVX. introduced space-level, base metal electrode (BME), X7R dielectric multi-layer ceramic capacitors (MLCCs) suited for use in manned and unmanned spacecraft and satellites. AVX said the devices provide higher capacitance values in smaller case sizes to reduce space usage and weight, which are key factors for space electronics. The capacitors also employ tin-lead plating with Flexiterm terminations to resist mechanical stress by allowing for more than twice as much board flexure as standard terminations.
AVX also offers the TCH series of hermetically sealed tantalum polymer chip capacitors for aerospace and other high-reliability applications. AVX said the TCH series was originally developed for a European Space Agency program that required extremely high capacitance and low equivalent series resistance (ESR).
Another supplier, KEMET Corp, announced a line of polymer capacitors suitable for the military and aerospace markets. Part of the company’s T540 and T541 Polymer COTS Series, the capacitors are targeted for decoupling and filtering applications that require very low ESR, high ripple current capability and improved capacitance retention at high frequency. These characteristics are suited for aerospace applications such as radar, power supplies and guidance systems.
Electronics distributors for aerospace applications
When sourcing from distributors, space contractors need to ensure they are engaging with reputable firms that are committed to avoiding counterfeit parts. This is a particular concern in the military/aerospace segment where many components have become obsolete.
Some distributors offer assurances that they can avoid counterfeits by engaging directly with suppliers and eschewing third-party purchases. For example, Arrow Electronics Inc. stated that for the last two decades it has bought end of life products in bulk directly from factories.
This allows Arrow to continue to sell thousands of obsolete parts as long as 10 years after they have been discontinued. Arrow’s parts come with Certificates of Compliance, which eliminate the risk of counterfeit components sabotaging space missions. By picking the right parts and taking the steps to avoid counterfeits, contractors can help reduce the risk of capacitor failures in outer space.