Putting Interconnects to the Test in the Harshest Environments

A satellite in low-Earth orbit might cycle between intense sunlight and deep shadow several times a day. As this happens, its internal electronics can be exposed to significant temperature changes. These systems also experience ongoing vibration throughout operation, as well as mechanical shock during major events like launch or deployment.

Ground-based systems introduce their own kinds of stress. Industrial equipment runs continuously in settings that expose components to mechanical load. Medical devices experience repeated sterilization cycles that can take a toll on materials and construction. In automotive systems, interconnects may sit close to parts that generate heat.

Within these harsh environments, interconnects must hold up even when conditions push them far from typical operating limits. Samtec, a global manufacturer of electronic interconnects, has developed a Severe Environment Testing (SET) program to determine how components will behave under heat, vibration, voltage stress and other conditions that exceed standard commercial test requirements.

What is SET?

SET builds on a multi-tiered testing structure that evaluates interconnect durability at increasing levels of stress.

Figure 1: Severe Environment Testing (Image source: Samtec)

At the foundation is Design Qualification Testing (DQT), which applies to all Samtec product series. DQT covers a range of baseline evaluations. Normal force measures how firmly contacts press together. Thermal aging examines how materials behave after long-term exposure to heat. Mating and unmating durability looks at how well a connector holds up to repeated use. Current-carrying capacity determines how much electrical current a contact can safely handle. Insulation resistance measures how well insulating materials prevent unintended current flow between contacts. Event detection monitors for brief interruptions in electrical continuity when the connector is subjected to mechanical stress. DQT also includes checks such as dielectric withstanding voltage (DWV), and mechanical shock and random vibration, which are explored further in the next section.

For products that require added assurance, Samtec offers the Extended Life Product program (ELP). ELP certifications involve more rigorous testing to evaluate contact resistance under simulated storage and field conditions. One example is ten-year mixed flowing gas testing, where gases such as sulfur dioxide, chlorine, hydrogen sulfide and nitrogen dioxide flow around components for two weeks to simulate harsh atmospheric conditions. ELP also includes high mating-cycle testing, ranging from 250 to 2,500 cycles, to assess how contacts perform after repeated use.

SET sits above both programs to focus on high-risk environments. It targets interconnects used in applications ranging from military/aerospace, industrial, medical, and automotive, to test connectivity, AI/machine learning, instrumentation, 5G networking, and broadcast equipment. Products qualified under SET are also approved for NASA Class D missions that include low-Earth orbit (LEO) satellites, SmallSats and CubeSats.

Outgassing considerations for space applications:

Outgassing is a key concern for systems that operate in vacuum environments. It occurs when non-metallic materials such as polymers or adhesives release small amounts of gas when exposed to heat or low pressure. In a vacuum, these vapors can settle onto nearby surfaces and may interfere with optics, sensors, or other components that are sensitive to contamination.

NASA’s ASTM E595 standard is commonly used to assess whether materials are suitable for these conditions. The test measures total mass loss (TML) and collected volatile condensable materials (CVCM), with acceptable thresholds of less than 1.0% TML and less than 0.10% CVCM. Samtec references NASA outgassing data to determine whether specific materials meet these criteria when space applications are involved. Although outgassing is not part of the SET test sequence, it is still relevant for SET-qualified products used in NASA Class D missions.

Key Stress Categories in SET

Samtec’s SET program subjects interconnects to a combination of thermal, mechanical, electrical, and environmental stresses that exceed what is typically required for commercial components.

Altitude testing:

Changes in altitude can affect the ability of insulating materials to withstand voltage. Dielectric withstanding voltage assesses how well a connector’s insulation can “hold its ground” when exposed to higher-than-normal voltage—similar to increasing pressure on a barrier to see if it leaks.

SET includes altitude testing that exceeds VITA 47.1 requirements. In this evaluation, a controlled over-voltage is applied at approximately 70,000 feet to confirm that the insulation continues to keep conductors isolated under electrical stress.

Temperature cycling and non-operating temperature testing:

Temperature changes can place significant stress on connector materials. Thermal expansion and contraction can shift materials over time, affecting contact resistance, plating, and overall mechanical stability. SET includes temperature cycling that moves parts between -65°C and +125°C, with time spent at each extreme before shifting to the next. Some evaluations involve as many as 500 cycles. These tests help show how an interconnect responds when it is exposed to sharp swings between hot and cold conditions.

SET also includes non-operating temperature testing to assess durability outside recommended ranges. Parts are cycled between -55°C and +105°C for 100 cycles, and between -65°C and +125°C for another 100 cycles. This type of testing helps confirm whether materials and connector structures remain stable when exposed to severe temperature excursions.

Mechanical shock and vibration:

Mechanical forces are another source of stress that can influence how well a connector performs over time. In many applications, electronics encounter sudden impacts, steady vibration, or a mix of both. These forces can come from equipment that rotates, from motors running nearby, or from machines operating across uneven surfaces. Over time, this kind of motion can affect how securely contacts meet and whether electrical connections remain stable.

SET includes both mechanical shock and random vibration testing to evaluate how interconnects respond to these conditions. Mechanical shock testing subjects components to a peak of 40 G using an 11 millisecond half-sine pulse, which represents a sharp, momentary impact. Random vibration testing exposes parts to motion ranging from 5 to 2,000 Hz at 12 gRMS, simulating the continuous shaking that can occur in environments such as industrial equipment, aerospace systems, or automotive applications.

Humidity exposure:

Moisture in the environment can also affect the materials inside a connector. High humidity and repeated humidity cycling can contribute to corrosion on metal surfaces or changes in insulation resistance.

SET includes humidity testing based on VITA 47.3 to evaluate how interconnects respond under these conditions. In this test, components are exposed to humidity levels far higher than they would normally encounter, for an extended period.

Electrostatic discharge (ESD):

When two surfaces come into contact and then separate, they can build up static electricity. If that charge suddenly transfers to a connector or nearby circuitry, it can disturb sensitive electronics or affect the surfaces where contacts meet. In everyday handling, even a small spark created by static buildup can reach surprisingly high voltages.

SET evaluates how interconnects respond to these events by exposing components to repeated electrostatic discharges at 5 kV, 10 kV, and 15 kV, with ten discharges applied at each level. The evaluation also incorporates VITA 47.1 ESD resistance criteria as part of the testing process.

Samtec’s SET-Qualified Products

The SET program spans several types of interconnect families from Samtec. These examples highlight some of the products that fall under SET test conditions.

Edge Rate:

Edge Rate connectors are qualified for altitude testing that measures DWV at 70,000 feet. The family uses a rugged contact geometry with a smooth, milled surface to reduce wear in high-mating-cycle applications. Edge Rate is built on a 0.80 mm pitch board-to-board format and is designed for high-speed systems, supporting data rates up to 56 Gbps PAM4. Shielded versions are also available for designs that require additional protection.

Tiger Eye:

Tiger Eye connectors are built to withstand the intense shock and vibration testing performed under SET. The system uses a 1.27 mm pitch and a multi-finger, heat-treated beryllium copper contact that helps maintain engagement under mechanical stress. Tiger Eye is available in board-to-board and wire-to-board formats, with options for surface-mount or through-hole assembly. The durability of the contact design makes it suitable for applications involving frequent mating cycles or vibration exposure.

SEARAY:

SEARAY connectors are included in the temperature-related evaluations in SET. The family features an open pin-field architecture available in 1.27 mm or 0.80 mm pitches, supporting high-density layouts with configurations reaching up to 500 I/O. The Edge Rate contact system is also part of the SEARAY design, enabling data rates up to 56 Gbps. Multiple board-to-board configurations are available, including mezzanine, coplanar, and right-angle layouts.

Tiger Claw:

Tiger Claw connectors appear in the SET-qualified list for the electrostatic discharge portion of testing, which includes exposure to discharge levels up to 15 kV. Built on a 0.100 inch (2.54 mm) square-post header and socket format, the system is listed as a general-purpose option for harsh environments that use larger pitch spacing or traditional header-and-socket layouts.

Samtec also offers digital models for 97 percent of its stocking parts on DigiKey to assist engineers during early stages of development.

To learn more, visit Samtec Severe Environment Testing.