Radiation-Hardened Electronics: An Essential Support for Space Technologies sin the Harsh Space Environment
Exploring the uncharted territories in outer space always comes with huge challenges of dangerous environments. Surviving in extreme environmental conditions in space is not easy either for humans or machines. Therefore, it is essential to equip the spacecraft with robust technologies such as radiation-hardened electronics to survive harsh radiations and temperatures in space.
Above the protected earth’s atmosphere, spacecraft are subjected to extreme temperatures, both hot and cold, and a significant threat of radiation damage. The temperature in space can range from the extremely cold, hundreds of degrees below freezing, to many hundreds of degrees above, especially if spacecraft ventures close to the Sun.
The threats such as vacuum, solar ultraviolet (UV) radiation, charged particle (ionizing) radiation, plasma, surface charging and arcing, extreme temperature, thermal cycling, micrometeoroids, and orbital debris can cause severe damage to the exterior material of the spacecraft. For instance, the major problem caused due to the radiation effect is noise and signal spikes, which occur due to single charged particle strikes. This results in inaccuracy and performance of the electronic devices used in satellites, deep-space probes, and launch vehicles.
Hence, the spacecraft equipped with strong and high-performance devices have a better chance to withstand the extremely harsh environmental conditions in space. The radiation-hardened electronics is one such technology that enables stronger spacecraft systems.
What are radiation-hardened electronics?
Radiation-hardened electronics, also known as rad-hard electronics, are electronic components including circuits, transistors, resistors, diodes, capacitors, single-board computer CPUs, and sensors that are designed to be less susceptible to damage from exposure to radiation and extreme temperatures (-55°C to 125°C).
Electrical components have become essential for various applications ranging from simple timers to most complex instruments such as satellites and supercomputers.
The electronic components that possess the capability to survive in the high radiation environment are essential for a successful space exploration mission. Radiation hardening is a survivability testing of electronic components for radiation environments that are commonly used in industries such as defense, energy sector, and aerospace.
Over the past few decades, the advancement in various electronic components and semiconductors has created opportunities for satellite and launch vehicle manufacturers to operate and survive in high-radiation environments. Additionally, the continuous use of technological advancements in electronics has made the electronics components much smaller in size and weight.
Due to the increasing demand for communication and Earth observation satellites, there is a significant rise in the demand for radiation-hardened electronics.
According to the BIS Research market report, the global radiation-hardened electronics for space applications market is estimated to reach $4.76 billion in 2032 from $2.34 billion in 2021, at a growth rate of 1.70% during the forecast period 2022-2032.
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Effect of Radiation on Spacecrafts and Satellites
When a spacecraft or satellite is exposed to the transient particles from solar events or solar particles interact with the surfaces of the spacecraft, it can affect the system in various ways such as spacecraft charging (SC), single event effects (SEEs), and total ionizing dose (TID). These effects are discussed as follows.
- Spacecraft Charging- Spacecraft charging (SC) is the formation of charge on spacecraft surfaces or in the interior walls; it causes variations in the electrostatic potential of a spacecraft surface concerning the surrounding plasma environment. The major space conditions that contribute to SC include the thermal plasma environment, high-energy electrons, solar radiation, and magnetic fields. Although SC has many damaging effects, electrostatic discharges appear to be the most dangerous of all. It can lead to structural damage, degradation of spacecraft components, and operational anomalies due to the damage to electronic components.
- Single Event Effects– Single event effects (SEEs) are individual events that occur when a single incident ionizing particle deposits sufficient energy to cause an effect in a device. SEEs are caused by two space radiation sources, namely, high-energy photons and cosmic rays. For cosmic rays, SEEs are typically caused by their heavy ion component. These heavy ions cause a direct ionization, i.e., if an ion particle traversing a device deposits sufficient charge, an event such as a memory bit flip or transient may occur.
Protons, usually trapped in the earth’s radiation belts or from solar flares, may cause direct ionization SEEs in very sensitive devices. However, a proton may more typically cause a nuclear reaction near a sensitive device area, thereby creating an indirect ionization effect and potentially causing a SEE.
- Total Ionizing Dose– Total ionizing dose (TID) refers to the amount of energy that ionization processes create and deposit in materials such as semiconductors or insulators when energized particles pass through them. TID can result in device failure or biological damage to astronauts. Radiation-induced trapped charges can build up in the gate oxide of a metal-oxide-semiconductor field-effect transistor and cause a shift in the threshold voltage. Such a device cannot be turned off even at zero volts applied if the shift is large enough. Under this condition, the device is said to have failed by going into depletion mode. In low Earth orbit, the main dose source is from electrons and inner belt protons, while the primary source is the outer belt electron and solar protons in geostationary orbit.
How do radiation-hardened electronics help in preventing damage to space technologies?
The process of radiation hardening and survivability testing is essential for the aerospace industry. These radiation-hardened electronics and systems enable the spacecraft to remain functional in the event of a large dose of electromagnetic radiation.
They have been manufactured and tested to resist different types of radiation damage that can occur in space, during high altitude flights, at scientific research facilities, and in nuclear reactors. It involves rigorous radiation survivability testing, which means bombarding electric components with radiation to determine how long they can operate in extreme conditions and, ultimately, which material will be the best choice for a given radiation-hardened component.
In the “hardening” process, rad-hard electronics are shielded in a layer of depleted boron and mounted on insulating surfaces instead of on conventional semiconductor wafers. This enables them to withstand higher radiation than commercial-grade chips. This process helps in preventing physical damage as well as technical damage, such as data losses or communications and processing errors that could make equipment malfunction.
Rad-hard electronics have extremely low failure rates in harsh radioactive and dangerous environments. Hence, they are often used by space agencies, private spaceflight companies, the defense community, and research scientists to assure consistently reliable performance and longer service life.
Over the past few years, there has been a drastic shift in the applications of space-based technologies. With the rapid growth in small satellite constellations for various applications such as Earth observation, remote sensing, and space-based broadband services, the demand for radiation-hardened electronic components has also significantly increased.
There are several advancements in radiation-hardened electronics with enhanced capability to manage space challenges at a low cost. Various radiation-hardened electronics that are currently used are onboard computers, microprocessors and microcontrollers, power sources, memory (solid-state recorder), field-programmable gate array, transmitter, and receiver (antennas), application-specific integrated circuit, and sensors.
Space is a huge market with unlimited opportunities, and radiation-hardened components are required across all platforms to provide seamless functionality. As a result, the market for radiation-hardened electronics for space applications is expected to be well-established.