Choosing the Best Aerospace PCB Connectors for Your Job

Gazing at a clear sky at night can be mesmerizing, perhaps even therapeutic. From a vantage point safely here on earth, space seems serene and safe. However, the opposite can be true for spacecraft, orbital and interplanetary. The space environment can subject mechanical and electrical systems to many hazards. These include radiation, extreme temperatures and significant vibratory forces during flight.

Electronic systems and PCBAs are typically somewhat shielded from a spacecraft’s external effects, but they are not immune to the impact. For example, some radiation particles can penetrate virtually any material and pose a threat to circuit boards, primarily if radiation-hardened electronics are not utilized. These hazards extend beyond individual boards and components to the greater electronic systems, meaning your aerospace PCB connectors’ choice is critical to system performance and reliability.

Let’s look at the challenges for circuit board interconnectivity about spacecraft and how to make the best selections for your aerospace PCBA design.

Challenges of PCB Connectivity in Space

Before discussing specific challenges for aerospace PCB connectors, it is helpful to understand the environment in which space vehicles operate. Space includes all elevations above the earth, whether within the earth’s atmosphere or beyond it. The earth’s atmosphere consists of five layers. All of these, except the mesosphere, which extends from 50 km (≅ 31 mi) to 85 km (≅ 53 mi), routinely consists of platforms that contain avionics or electronics systems aboard aircraft, spacecraft and satellites—the most common aerospace vehicle. Each has specific environmental conditions, some of which are hazardous.

Hazards for PCBA Connectors in the Space Environment

There are three primary hazards for platforms and the electronic systems--boards and connectors--that comprise them when operating in space. These are vibration and shock, temperature extremes and radiation.

• Vibration hazard

Vibration is a concern for all space vehicles as the most shock occurs during launch. The most damaging effects are breakage or material deformation (which may be instantaneous) and material fatigue that may have long term impact.

• Temperature hazard

For board connectors, the hazard of extreme temperature is most often more of an internal issue than an external. For example, during the launch, temperatures greater than 3,000 °C (or nearly 6,000 °F) may be present near the rocket engine. These exceed the PCBA temperature limits for most materials used in aerospace electronics systems. Therefore, isolation and thermal control systems are critical onboard space vehicles.

• Radiation hazard

Probably the most dangerous hazard in space is high-energy ionizing radiation, which can be present at any of the earth’s atmospheric levels and beyond. Certain radiation particles can penetrate virtually any material and cause charge buildup on conductive elements or atomic dislocation to impact device functionality. Similar to vibration and shock, there may single event effects (SEEs) or issues that evolve.

Once the hazards present for aerospace PCB connectors are understood, a set of guidelines will help you make the best selections.

How to Choose Your Aerospace PCB Connectors

There are many connectors for PCBAs available, and selecting the best type for your application is not a simple proposition. Connector selection cannot be made in isolation. It is imperative to know the connector type for the PCBA(s) or electronic devices with which your board must attach to optimize signal TX/RX and power transfer. There are also physical concerns, such as enclosure clearances and aperture alignment for wiring, cabling, or the connector.

Additionally, as connectors are circuit board components, they must adhere to aerospace industry standards for PCBA manufacturing. This adherence includes ensuring that adequate testing requirements for space grade connectors are met. Therefore, the best means for choosing aerospace connectors for your design requires that you incorporate all of the following:

Considerations for Aerospace PCB Connector Selection

• Regulatory requirements

  Connectors used on aerospace platforms must satisfy material requirements as stipulated by EIA/ECA-364-18B, mating and unmating force standards as defined by EIA-364-13E, continuity during mechanical shock as stated in EIA-364-27C and other testing regimens based on the installation environment.

• External environmental conditions

  For external cabling and connectors, temperature range and radiation exposure are primary considerations.

• Internal environmental conditions

  Internal environment concerns include temperature range, humidity, environmental EMI and external radiation that may penetrate the spacecraft’s interior.

• Operational requirements

  For most space vehicles, repair or replacement of electronic systems, including connectors, is not possible. Therefore, well-defined lifetime operational requirements must be established and utilized in selecting the best connectors.

Operating in space can be hazardous; one must meet stringent regulations set forth by the aerospace industry. Primary considerations influencing your connector decision include evaluating the space vehicle’s internal and external environment and whether the PCBA is a part of a mission critical system.

In addition to the considerations above, component supply chain management can also be a significant concern.