Features

Design to Work in Harsh Environments and Follow Standardization

For the interconnect devices to survive in harsh environments, in addition to radiation resistance, they must include other parameters that may not be required for commercial-grade components. This includes meeting requirements for shock and vibration as specified in MIL-STD 883. It is strongly recommended that the devices be sealed from moisture and thermal shock within a wide range of operating temperature (typical -40°C to +100°C). Keep in mind that some devices may slow down when the temperature goes to the extreme, so it is important to measure sustained performance at those temperatures.

Designing or selecting open standard-based (VITA 66) interconnect devices ensures that the solutions will follow the lifespan of the standards and will not be easily obsoleted, as is often the case in proprietary or custom designs. To ensure that the devices meet minimum standards, they should meet – but are not limited to – the following industry standards:

  • MIL-STD-883, Method 2007.3 (vibration tests)

  • MIL-STD-883, Method 2002.4 (mechanical shock tests)

  • MIL-STD-883, Method 1011.9 (thermal shock tests)

  • MIL-STD-202, Method 103B (damp heat tests)

  • MIL-STD-810, Method 502.5 (cold storage tests)

  • MIL-STD-883, Method 1010.8 (thermal cycling tests)

  • MIL-STD 883 (shock and vibration)

  • MIL-STD-883G, Method 1019.7 (total Ionizing Dose and Cobalt 60 gamma rays tests)

  • Total Non-Ionizing Dose (TNID) tests

  • Open VITA 66 standards

  • ECSS-Q-ST-60-15 Space Assurance

Achieving SWaP and Reliability

Figure 3. A different view of the SpaceABLE fiber-optic transceiver shows the connector for fiber-optic cable connection. At the bottom is the view of the ball grid array (BGA) for surface mount soldering.

Weight becomes increasingly significant in space transportation and applications. The cost of sending 1 kg is estimated to be $50,000. Designing products to achieve optimal SWaP and high reliability with high MTBF is always the ultimate goal.

In space and military missions, failure cannot be tolerated. Satellites will be in orbit for many years, and repairing failed parts is not only difficult but also very costly. Therefore, designing for compact-size, ruggedness and high reliability will help developers stay competitive in the race to space. For example, the SpaceABLE interconnect solution with multiple lanes can yield as much as 150 Gbps. For reliability, a combination of sealing, ruggedness and radiation-resistant design plays into the longevity of the device. Its lifespan can range from a few years to over 20 years. The total cost of ownership including maintenance can be kept to a minimum with high-reliability devices.

Conclusions

Aeronautical applications face many design challenges that are unique to their intended environment. The best practices for optical interconnect design for space applications include the use of radiation-resistant technology to defend against space radiation, the use of components and devices that are designed to operate in harsh environments, and meeting SWaP and long-term reliability requirements. Finally, it is recommended to follow open standards like VPX and to look for solutions that comply with MIL and quality standards.

This article was written by Guillaume Blanchette, Space Industry Manager, and David Rolston, Ph.D., Chief Technology Officer, Reflex Photonics (Kirkland, QC, Canada). For more information, visit here.