From the SpaceX Starlink crash, we can see the challenges of aerospace-grade circuit design

Recently, the U.S. Space Exploration Technology Corporation (SpaceX) stated that due to a geomagnetic storm, as many as 40 of the 49 Starlink satellites launched by the company on the 3rd of this month were damaged the next day. 

This incident further emphasizes the importance for space system designers to select highly reliable space-grade products for satellite control systems.

However, electronic devices face various unpredictable challenges in space, from extreme temperatures to large amounts of space radiation. In addition, if a failure occurs, the satellite cannot be repaired.

Therefore, there is always a need for robust electronic components with a high mean time to failure (MTTF), which is related to the reliability or average lifespan of a component.

Space-grade circuit design challenges

There are many things to consider when designing cutting-edge aerospace electronics.

The first obstacle that electronic devices must withstand is the vibration and noise generated during startup. These sudden vibrations can damage or even short-circuit the device; therefore, aerospace-grade electronic products must pass various vibration and shock absorption tests.

Another challenge is the high electrostatic discharge caused by the photovoltaic effect and the low-density plasma surrounding the satellite. Electrical components must withstand discharges of up to 20,000 V in the space environment. To prevent this, it is best to use materials that are resistant to charge accumulation.

In addition to these issues, space-grade electronics also face huge thermal management challenges. Electronics are exposed to extreme temperature fluctuations in space, and ceramic packaging provides a high degree of protection from harsh environments.

However, the problem lies in the heat generated by electronic devices, as heat conduction does not occur in a vacuum. When components are exposed to high temperatures, their life expectancy is severely reduced.

Of course the biggest hurdle when it comes to reliability of components in space is radiation.

In space, electronic devices are susceptible to a variety of ions and uncharged particles, such as alpha and beta particles, photons, X-rays, and gamma rays.

An example of the effect of particles on a circuit. Image courtesy of Altium

These particles can strike electronic components and produce undesirable behaviors categorized as Total Ionizing Dose (TID) and Single Event Effects (SEE). TID is a long-term failure that is related to MTTF.

The effects that lead to TID are usually related to charge accumulation in semiconductor devices. Charge accumulation can lead to leakage current, reduced gain, degraded input-output characteristics, and more serious permanent damage.

On the other hand, SEE is caused by energetic particles injecting charge through the package. These effects can cause bit flips, memory state changes, and many permanent issues such as gate oxide damage, latch-up, etc.

As we have observed, electronic devices face many unpredictable challenges in space. In addition, as modern satellites adopt high-speed communication circuits and other onboard processing units, the instruments in satellites are becoming more and more complex. Therefore, there is a need for space-grade components that can simplify system development.

Microchip's Hybrid Space Power Converters

Considering all these challenges in designing space electronics, Microchip recently released a series of products that are driving the development of new space-grade power conversion.

Recently, Microchip released the SA50, a 50W hybrid space-grade power converter series with standard outputs of 3.3V, 5V, 12V, 15V, and 28V single and triple output configurations. These devices are designed to simplify system development for space applications.

Space system designers lack the flexibility in power converters to combine circuits with non-standard input voltages. Therefore, Microchip's flexible converters help designers meet specific voltage and current requirements and simplify their systems.

Microchip's family of space-grade converters. Image courtesy of Microchip

Overall, the SA50 converters are EMI-compliant and radiated-hard. The converters are specified with an MTTF of 8 million hours and 87% efficiency, which is said to be the highest of any hybrid space-grade DC-DC converter.

BAE Systems awarded radiation-hardened microelectronics contract

As space is becoming an important part of the electronics industry, with the advent of satellites and communication hardware, more space-grade components are needed.

BAE Systems was recently awarded a $60 million contract from the Rock Island Army Contracting Command to develop space-grade microelectronics in conjunction with Intel's commercial foundry, Intel Foundry Services.

Currently, the most advanced ASICs (application-specific integrated circuits) and other integrated circuits available commercially are not space-grade. Therefore, BAE Systems' FAST Lab and Intel aim to expand available electronic technologies for space applications. Together, they are building a new design library to pave the way for advanced space-grade microelectronics.

In addition to Intel Foundry Services, BAE Systems is working with a team consisting of Cadence Design Systems, Carnegie Mellon University, Movellus, Reliable MicroSystems and Sandia National Laboratories.

Collaborative development of aerospace-grade FPGA

BAE Systems and Intel aren’t the only companies looking to get into space electronics design.

CAES and Lattice Semiconductor recently announced a collaboration to release a space-grade Lattice FPGA.

The Certus-NX-RT and CertusPro-NX-RT FPGAs developed by NVIDIA are compact and energy-efficient. They are based on 28 nm process technology and use a radiation-tolerant, FD-SOI manufacturing process with temperature-tolerant tin-lead (SnPb) terminals.

A graphic outlining some of the benefits that Lattice and CAES bring to this collaboration. Image courtesy of CAES

The collaboration will address the growing demand for low-power space-grade FPGAs. Esam Elashmawi, Chief Strategy and Marketing Officer at Lattice Semiconductor, believes that with Lattice's FPGA technology and CAES' aerospace knowledge, they can accelerate the processing needs of space applications.

Driving more radiation-hardened and space-grade devices

Designing space systems to operate continuously for decades is a challenging and complex task, and as semiconductor devices increase in size and complexity, the task of radiation hardening becomes increasingly complex.

The shrinking feature sizes of devices make them more susceptible to radiation effects. Moreover, there is always a trade-off between performance and reliability, which is also a challenge that suppliers of space-grade components are working hard to overcome.

However, the lack of space-grade state-of-the-art electronic systems is slowly being addressed as many companies and institutions emerge with various radiation-hardened devices.