Space electronics face extreme conditions not found on Earth. Careful design and implementation of them help keep spacecraft and the astronauts within them safe.
So, we’re planning a trip into space. What do we need? Well, lots of things.
But first and foremost, according to NASA, we need systems that allow us to live and breathe. And not just any old system – ours must “be highly reliable while taking up minimal mass and volume.”
Second, we’ll need proper propulsion because the “farther into space a vehicle ventures, the more capable its propulsion systems need to be to maintain its course on the journey with precision and ensure its crew can get home.”
Next up: we need the ability to keep the heat off. “The farther a spacecraft travels in space, the more heat it will generate as it returns to Earth,” NASA writes. “Getting back safely requires technologies that can help a spacecraft endure speeds 30 times the speed of sound and heat twice as hot as molten lava or half as hot as the sun.”
What about protection from radiation, you may be asking. Yep, we’ll need that, too. According to NASA, “As a spacecraft travels on missions beyond the protection of Earth’s magnetic field, it will be exposed to a harsher radiation environment than in low-Earth orbit with greater amounts of radiation from charged particles and solar storms that can cause disruptions to critical computers, avionics, and other equipment. Humans exposed to large amounts of radiation can experience both acute and chronic health problems ranging from near-term radiation sickness to the potential of developing cancer in the long-term.”
Finally, we’re going to have to be able to maintain constant communication and navigation. “Spacecraft venturing far from home go beyond the Global Positioning System (GPS) in space and above communication satellites in Earth orbit,” writes NASA. “To talk with mission control in Houston, (we’ll) use all three of NASA’s space communications networks.
“As (we) rise from the launch pad and into cislunar space, (we’ll) switch from the Near Earth Network to the Space Network, made possible by the Tracking and Data Relay Satellites, and finally to the Deep Space Network that provides communications for some of NASA’s most distant spacecraft.”
Of course, there’s more to it than that. But, without these five technologies, our trip doesn’t get anywhere close to getting off the ground. And, without Electrical, Electronic, and Electromechanical (EEE) components, we’re not even thinking about slipping the surly bonds of Earth.
Differences In Space Vs. Earth Electronics
Environmental Challenges: Space components must withstand extreme temperatures, vacuum conditions, and high radiation levels, which are not typically encountered on Earth. This requires the use of materials and designs that can endure such harsh conditions.
Reliability and Performance: Space applications demand high reliability and performance due to the difficulty of repairing or replacing components once deployed. This often involves rigorous testing and qualification processes to ensure components can survive the mission duration without failure.
Radiation Hardening: Unlike most Earth applications, space components must be radiation-hardened to prevent malfunctions caused by cosmic rays and solar radiation. This involves using specific materials and design techniques to mitigate radiation effects.
Mechanical Robustness: Components used in space must be mechanically robust to withstand the vibrations and shocks experienced during launch and operation in space.
Space Is A Dangerous Place For Electronics
Without electronics, there would be no communication, life support, attitude control, or navigation. Numerous critical systems that all staffed spacecraft have relied upon will be eliminated, including:
Ground-based radar tracking to plot the flight path
Communication with anything beyond the spacecraft
Mission Control
Flight computer with preprogrammed burns
Spacecraft-based radar for docking/landing maneuvers
Even with today’s fully functioning, reliable electronics designed specifically for the journey into space, there are problems. For starters, there are the vibrations that occur when a rocket is launched into space.
These vibrations cause small motion throughout all ranges, sometimes referred to as harmonics. A space launch is extremely violent and creates an unbelievable amount of vibration through a large range of harmonics for a long time. If the electronics on board aren’t strong enough to survive the vibration harmonics of a space launch, they’d simply shake so much they’d develop small cracks that would make them stop working.
Then there are the temperatures in space which vary from hundreds of degrees below freezing to hundreds of degrees above. For instance, the temperature on the moon can range from 410° below Fahrenheit to 250° above depending on the time of day and location.
For electronics, this temperature range can be dangerous to long-term use. Specifically, many electronic components such as integrated circuits or chips are only rated for -40° to 160° Fahrenheit, although companies make specialty components to withstand extreme temperatures.
The near vacuum of space can be catastrophic to any self-captured pocket of an electro-mechanical assembly such as a plastic boss that a screw goes into. In space, a small self-captured pocket like this becomes a mini pressure vessel and, as a result, any device subject to a vacuum must have relief holes to prevent accidental pressure build-up and the potential for explosions.
Speaking of the near vacuum of space – that’s where you’ll find atomic oxygen (O), a key component of Earth’s mesosphere and lower thermosphere, where it controls energy balance and photochemistry, and also can be used to track dynamical motions. O is extremely reactive with some metals making it dangerous to expose them to space’s near vacuum without industry-standard coatings that do not react to O. Most electronics’ printed circuit boards include these metals and, unless protected, they will be attacked by O and corrode very quickly.
Electronics are relatively safe from these outcomes in a controlled environment such as the International Space Station but would probably not survive very long if taken directly into space.
Keeping Electronics Safe In Space
We’ve previously written about how space agencies are keeping electronics safe in space. Let’s take that one step further and look specifically at components such as resistors, capacitors, and inductors:
Capacitors: Space-based capacitors are predominantly ceramic and tantalum types, designed to handle high voltages and temperatures. They are used in power management, filtering, and energy storage applications.
Resistors: Commonly used resistors in space include tantalum nitride and tin oxide types, which are selected for their stability and reliability in high-radiation environments. They are used in various applications, including power regulation and signal processing.
Inductors: Inductors used in space are designed for electromagnetic compatibility and are used in power supplies and communication systems. They must be robust and capable of operating in high-frequency environments.
Electronic components such as these used in space differ significantly from those used on Earth due to the unique challenges noted above, and designing and deploying electronic systems for space applications involves addressing these issues. For instance, radiation, the effects of which can cause single-event effects (SEE) and total ionizing dose (TID) damage. In addition, high-energy particles can cause malfunctions in electronic circuits, leading to system failures or data corruption.
Several strategies are employed to mitigate radiation effects on space-based electronics, including radiation hardening, a process that involves designing and manufacturing electronic components to withstand high levels of radiation exposure.
Radiation-hardened components, according to City Labs, are specially designed semiconductors and other electronic parts that can tolerate much higher radiation doses than standard commercial components. They often use different materials or manufacturing processes to increase radiation resistance. Some missions use a radiation-tolerant approach rather than full radiation hardening, which may involve using more robust commercial components and additional protective measures.
While not always the primary method, shielding can provide additional protection, writes Stack Overflow. Spacecraft may incorporate radiation-absorbing materials to reduce the amount of radiation reaching sensitive electronics, and critical components may be positioned within the spacecraft to maximize natural shielding from other structures and less sensitive equipment.
Temperature extremes also pose a significant challenge for electronics used in space and several strategies are employed to mitigate these temperature-related issues including thermal management techniques. According to Proto-Electronics, space-grade PCBs often use ceramic materials with low coefficients of thermal expansion, providing better stability and reliability in extreme temperature fluctuations.
A second technique is radiative heat transfer. For instance, in the vacuum of space satellites are designed to radiate excess heat out into space. Thoughtful component selection is needed to combat the effects of temperature extremes as well. Space electronics use components rated for extreme temperatures, often specified as military, aerospace, or space-grade in datasheets. Ceramic-packaged components are preferred as they can withstand repeated temperature fluctuations, provide better hermeticity, and remain functional at higher power levels and temperatures.
A third danger – the vacuum conditions of space itself – can lead to outgassing, where materials release gases that can deposit on and damage electronic components. This requires careful selection of materials and packaging.
The development of radiation-hardened plastic packaging, such as QML Class P, offers a lighter alternative to traditional ceramic packaging while still meeting reliability standards. In addition, using materials that minimize outgassing and can withstand the vacuum of space is critical to preventing contamination and ensuring long-term reliability.
All of the solutions to the problems of operating the many electrical systems needed to operate in space must also factor in the unique properties of space vehicles. Space missions often have strict constraints on size, weight, and power meaning electronics must be highly efficient and compact.
Space electronics must also undergo rigorous testing and qualification to ensure they can survive launch vibrations and operate reliably in space. This includes meeting government standards such as the Qualified Manufacturers List (QML) for radiation-hardened devices.
Designed For The Harsh Environment Of Space
Electronics used in space are designed to handle challenges that are not present on Earth, such as radiation, extreme temperatures, and the vacuum of space. By employing specialized materials, rigorous testing, and innovative designs, engineers can ensure that these systems operate reliably in the harsh conditions of space.
As space exploration and satellite deployment continue to expand, the development and innovation in the electronics they depend on remain crucial to the success of these missions.