High Temperature Electronics Aspect of Venus Landers Planet Venus has always been an interesting subject for humanity. Improving and understanding Venus is very important. It is the second planet after the Sun, it orbits the Sun 224.7 days from Earth. The atmosphere of this planet is very difficult for any type of surface exploration. The atmospheric composition of Venus is approximately 96.5% CO2, 3.5% nitrogen, and traces of SO2, HCL, and HF. However, Venus' atmosphere is thicker than Earth's, so the nitrogen content is almost four. times that of the Earth. Our main goal is to design a probe that will survive on the surface of Venus. We will therefore focus on the state of the troposphere which extends from the surface to a radius of 65 km from the planet. The surface air density is 67 kg/m3, the surface temperature is 467°C, and the surface pressure is 90 Earth atms. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get the original essay High-temperature electronics play a critical role in missions to Venus. These technologies are still under development for Venus planetary exploration applications. Due to the lack of electronics capable of collecting and transmitting data at the +450°C temperature of Venus, almost all proposed missions were of very limited duration to explore this planetary environment. In the past, few landers were sent to the surface of Venus but due to lack of high temperature electronics and old technology, they did not survive more than almost 2 hours. Main problem The atmospheric conditions on Venus are very extreme, so it is difficult to extend the operating time of the electronic circuit at high temperatures. Due to the very high temperature (approximately 500°C) and pressure (approximately 90 atmospheres) on Venus, the survivability of the active device, passive device and packaging materials is a challenge. State of the art Many agencies have deployed spacecraft on Venus, more than 23 so far, such as landers, balloons and probes. Here we have a quick overview of ancient Venus landers: As can be seen, in all cases the maximum surface survival time was 2 hours and 7 minutes. Besides the old mechanical technology, no high temperature batteries/electronics were used for these landers. Thanks to modern technology, instead of a heavy and big lander, we can have a small Rover. Due to the hellish location of Venus, for a long period of surface exploration, the rover contains special components such as: An integrated pressure vessel with advanced thermal control. High-temperature, low-consumption electronics. Certain components, for example a sensor and/or telecommunications at 480°C. .Rapid sample collection and analysis system at 480°C.High temperature energy storage.Cooling system.One of the most important parts of a Venus rover directly connected to high temperature electronics. temperature is the pressure vessel with advanced thermal control. It protects the rover's brain system from the hostile environments of the surface of Venus (pressure, heat and oxidation). The advanced thermal control system that fits inside thePressure vessel serves two functions. The first is to minimize heat transfer from the environment to electronic devices and the second is to match the heat generated by internal electrical components such as the power system, transmitter, and instruments. Certain technologies have been designed and exploited. Devices made of solid materials can operate at high temperatures, such as silicon and silicon carbide. Thermionic vacuum devices are inherently high-temperature devices, as they are designed to operate between 600°C and nearly 1000°C. °C. These devices have been shown to operate in a 500°C environment, but further optimization is still required. The challenges of developing this technology include integration and power requirements. The recent generation of semiconductors, including silicon carbide (SiC), diamond, and gallium nitride, have enabled short-term demonstrations of electrical devices at temperatures of 550°C to 650°C. Until now, these devices only had a lifespan of very few hours to operate at these high temperatures. Over a long period of time, the stability of these devices is very important. NASA Grc developed the SiC-based technology transistor for continuous operation at 500°C for more than 3,000 hours. In this essay, I will focus on the high temperature electronics aspect of Venus Landers and take a quick look at NASA GRC's test results on high temperature components and find the best materials and devices.SolutionI will explain the solution in detail. Generally, high-temperature electronic components for a Venus lander are divided into three categories: active devices, passive devices, packaging materials, and high-temperature pressure sensors. We will look at these categories and their subsets. Active Devices Solid State (SOI Devices): Using active thermal control that contains a powerful cooling system, we can maintain the temperature inside the pressure vessel ~300°C (theoretically). In this case, low-power SOI electronics, operating at 300°C, can be considered for use inside the thermally controlled Venus Lander. This electronics is currently used in oil drilling equipment. Such electronics would help ease the thermal control burden and significantly increase survivability and mission lifespan. Leakage current could also be managed. Solid State (Wide Bandgap Devices) When using passive thermal controls, wide bandgap semiconductors must be considered for temperatures above 300°C. . Looking at the table above, we can see that gallium nitride, silicon carbide, diamond, and thermionic vacuum devices are all capable of operating at the temperature of the planet Venus (~500°C). But considering factors such as cost, lifespan and technological range, silicon carbides (SiC devices) are the best choice for this task. However, on paper the maximum operating temperature of SiC is 600 °C, but problems with diffusion and oxidation of the metal contact layers significantly reduce both operating temperature and lifespan. In this case, appropriate metal layers should be chosen to reduce diffusion and oxidation. Other facts such as the integration and metallization process must also be taken into account. Recently, scientists from NASA's Glenn team invented a new type of SIC device.4H-SiC-based JFET integrated circuits (24 transistors, with 2 levels of metal interconnection) and ceramic package for over 1,000 hours of constant operation at 500°C for testing in the Earth's atmosphere. This is a big step forward for Venus landers because this SIC device does not need a cooling or thermal system or even a pressure vessel. The characteristics of current, voltage and some key parameters are very good, as shown below. Venus surface test steps on 4H-SiC JFET. a) The complete assembly showing the SIC ring oscillator chip before heated testing. b) Complete assembly before thermal testing show the mesh screen cap which allows immersion of the chips in the simulated atmosphere of Venus during testing. c) And after the 1,000 hours of testing under Venus surface conditions, the cap of the next mesh screen is removed. shorted power supply by removing nickel alloy wires. Thermionic Vacuum Tubes This is an inherently high temperature device that controls the electrical current between the electrodes in the vacuum tank. The vacuum tube relies on thermionic release of electrons from the hot filament. They are among the first and oldest high-temperature electronic devices. Although with the invention of transistors in the 1950s, these tubes almost disappeared from the electronics industry, they are still useful in certain cases related to microwave amplifiers, high frequency amplifiers and especially for pressure sensor preamplifier for Venus rovers. The figures below show vacuum tubes and a concept of internal components. For Venus rovers, the use of TVT can be considered because the cathode is designed to operate between 700 and 900°C. Yet these tubes still need to be optimized for Venus' harsh environment, as their use for Venus rovers presents some challenges. Challenges related to packaging, high level of integration, shelf life, power supply, size and weight. The graphs below show the influence of temperature on thermal vacuum tubes. Recent tubes use the cathode of the filament. This is a directly heated tube. The figure and concept below shows a vacuum tube including the heater, cathode, grid and anode. As mentioned earlier, TVT devices can be used for the high temperature pressure sensor amplifier in a Venus rover. The thermionic vacuum tube preamplifier was evaluated at room temperature and 500°C. The results are shown below: Passive devicesResistors: For a Venus rover, resistors are essential requirements for enabling a wireless system at high temperatures. High temperature resistances constitute one of the great challenges of Venus missions and this technology is still in development. Currently HT resistors are capable of operating at +500°C but with a limited lifespan. There are some factors for choosing the best resistor for the Venus rover, such as: Noise Thermal stress Interdiffusion Oxidation Looking at the table, we can see that the Ruthenium Silver and Ruthenium Oxide resistors have the highest maximum operating temperature. Ruthenium oxide also features superior stability, low thermal stress and low noise. But the main problem with these two resistors is that ruthenium is very rare and difficult to find. In this case, the cost of these resistors would be high. So technically we should look for another type of high temperature resistors. On the other hand, we have thin film and thick film resistors. The notable advantage ofthese resistors is that they are based on a ceramic substrate and that they no longer need mechanical fixing. Recently, a new type of thin film nickel-chromium resistors (NiCr) has been introduced by scientists. NiCr resistances are stable at almost 10% at 300°C. They have a high stability rate and low noise (not as good as ruthenium resistors). But the biggest advantage is the lower price. In my opinion, and considering the factors of cost, stability and maximum temperature, NiCr thin film resistors are the best choice for a long duration surface mission on Venus. Capacitors: Besides resistors, capacitors are also key elements of the high-temperature wireless system for Venus rovers. Current capacitors are not ready for a long-term surface mission on Venus. This technology is still in development. Innovations on all fronts, including materials, device design and packaging, are pursued. Before making a capacitor for extremely harsh environment, we need to consider some parameters like capacitance, leakage current, equivalent series resistance, rated voltage, dissipation factor, dielectric absorption and efficiency volumetric or weight. Here we will take a look at some of the famous high temperature capacitors. X7R: Capacity is strongly dependent on temperature. High current leakage at high temperature.NP0: Stable up to nearly 500°C with zero capacitance coefficient. High temperature dissipation problem. Piezoelectric: composition selected to achieve peak capacitance and dissipation factor for specified temperatures. Difficult to implement. Diamond: Theoretically functional up to almost over 500°C with stable and high capacity. Still under development to achieve uniform diamond film and stable metal contacts. Air gap/parallel plate: low capacity, but stable over the entire temperature range. Very large surface capacitors would be necessary. All the capacitors mentioned have a limited lifespan for the harsh environment of Venus, but recently a new design of high temperature capacitors has been invented by scientists. It is known as MIM (Metal Insulator andMetal Capacitors). The MIM capacitor is composed of two parallel plates with a dielectric layer between the plates. A microstrip line is connected to each plate. I think MIM capacitors based on SiC technology are the best choice for Venus rovers. However, these capacitors still need to be optimized due to their limited lifespan. It is expected that by +2020, scientists will be able to manufacture MIM capacitors with a long lifespan. Oscillators: Oscillator is one of the important components of wireless sensor system for signal generation, which is modulated by the sensor and the data will be transmitted to colder environments. , NASA's Glenn team is working on high-temperature oscillators to enable the advancement of SiC devices, as well as for the improvement of passive devices. The figure below shows a prototype HT oscillator that was tested by the Glenn team under conditions similar to those on the surface of Venus. Oscillator with SIC MESFET and capacitors with ceramic chip, spiral inductor and interconnections. Packaging Materials For harsh environments, packaging is required for operation. of sensor and electronics technologies beyond those of ordinary electronics and sensors. For Venus missions, sensors and electronics..

Essay / High Temperature Electronics Aspect of Venus Landers Planet Venus has always been an interesting subject for humanity. Improving and understanding Venus is very important. It is the second planet after the Sun, it orbits the Sun 224.7 days from Earth. The atmosphere of this planet is very difficult for any type of surface exploration. The atmospheric composition of Venus is approximately 96.5% CO2, 3.5% nitrogen, and traces of SO2, HCL, and HF. However, Venus' atmosphere is thicker than Earth's, so the nitrogen content is almost four. times that of the Earth. Our main goal is to design a probe that will survive on the surface of Venus. We will therefore focus on the state of the troposphere which extends from the surface to a radius of 65 km from the planet. The surface air density is 67 kg/m3, the surface temperature is 467°C, and the surface pressure is 90 Earth atms. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get the original essay High-temperature electronics play a critical role in missions to Venus. These technologies are still under development for Venus planetary exploration applications. Due to the lack of electronics capable of collecting and transmitting data at the +450°C temperature of Venus, almost all proposed missions were of very limited duration to explore this planetary environment. In the past, few landers were sent to the surface of Venus but due to lack of high temperature electronics and old technology, they did not survive more than almost 2 hours. Main problem The atmospheric conditions on Venus are very extreme, so it is difficult to extend the operating time of the electronic circuit at high temperatures. Due to the very high temperature (approximately 500°C) and pressure (approximately 90 atmospheres) on Venus, the survivability of the active device, passive device and packaging materials is a challenge. State of the art Many agencies have deployed spacecraft on Venus, more than 23 so far, such as landers, balloons and probes. Here we have a quick overview of ancient Venus landers: As can be seen, in all cases the maximum surface survival time was 2 hours and 7 minutes. Besides the old mechanical technology, no high temperature batteries/electronics were used for these landers. Thanks to modern technology, instead of a heavy and big lander, we can have a small Rover. Due to the hellish location of Venus, for a long period of surface exploration, the rover contains special components such as: An integrated pressure vessel with advanced thermal control. High-temperature, low-consumption electronics. Certain components, for example a sensor and/or telecommunications at 480°C. .Rapid sample collection and analysis system at 480°C.High temperature energy storage.Cooling system.One of the most important parts of a Venus rover directly connected to high temperature electronics. temperature is the pressure vessel with advanced thermal control. It protects the rover's brain system from the hostile environments of the surface of Venus (pressure, heat and oxidation). The advanced thermal control system that fits inside thePressure vessel serves two functions. The first is to minimize heat transfer from the environment to electronic devices and the second is to match the heat generated by internal electrical components such as the power system, transmitter, and instruments. Certain technologies have been designed and exploited. Devices made of solid materials can operate at high temperatures, such as silicon and silicon carbide. Thermionic vacuum devices are inherently high-temperature devices, as they are designed to operate between 600°C and nearly 1000°C. °C. These devices have been shown to operate in a 500°C environment, but further optimization is still required. The challenges of developing this technology include integration and power requirements. The recent generation of semiconductors, including silicon carbide (SiC), diamond, and gallium nitride, have enabled short-term demonstrations of electrical devices at temperatures of 550°C to 650°C. Until now, these devices only had a lifespan of very few hours to operate at these high temperatures. Over a long period of time, the stability of these devices is very important. NASA Grc developed the SiC-based technology transistor for continuous operation at 500°C for more than 3,000 hours. In this essay, I will focus on the high temperature electronics aspect of Venus Landers and take a quick look at NASA GRC's test results on high temperature components and find the best materials and devices.SolutionI will explain the solution in detail. Generally, high-temperature electronic components for a Venus lander are divided into three categories: active devices, passive devices, packaging materials, and high-temperature pressure sensors. We will look at these categories and their subsets. Active Devices Solid State (SOI Devices): Using active thermal control that contains a powerful cooling system, we can maintain the temperature inside the pressure vessel ~300°C (theoretically). In this case, low-power SOI electronics, operating at 300°C, can be considered for use inside the thermally controlled Venus Lander. This electronics is currently used in oil drilling equipment. Such electronics would help ease the thermal control burden and significantly increase survivability and mission lifespan. Leakage current could also be managed. Solid State (Wide Bandgap Devices) When using passive thermal controls, wide bandgap semiconductors must be considered for temperatures above 300°C. . Looking at the table above, we can see that gallium nitride, silicon carbide, diamond, and thermionic vacuum devices are all capable of operating at the temperature of the planet Venus (~500°C). But considering factors such as cost, lifespan and technological range, silicon carbides (SiC devices) are the best choice for this task. However, on paper the maximum operating temperature of SiC is 600 °C, but problems with diffusion and oxidation of the metal contact layers significantly reduce both operating temperature and lifespan. In this case, appropriate metal layers should be chosen to reduce diffusion and oxidation. Other facts such as the integration and metallization process must also be taken into account. Recently, scientists from NASA's Glenn team invented a new type of SIC device.4H-SiC-based JFET integrated circuits (24 transistors, with 2 levels of metal interconnection) and ceramic package for over 1,000 hours of constant operation at 500°C for testing in the Earth's atmosphere. This is a big step forward for Venus landers because this SIC device does not need a cooling or thermal system or even a pressure vessel. The characteristics of current, voltage and some key parameters are very good, as shown below. Venus surface test steps on 4H-SiC JFET. a) The complete assembly showing the SIC ring oscillator chip before heated testing. b) Complete assembly before thermal testing show the mesh screen cap which allows immersion of the chips in the simulated atmosphere of Venus during testing. c) And after the 1,000 hours of testing under Venus surface conditions, the cap of the next mesh screen is removed. shorted power supply by removing nickel alloy wires. Thermionic Vacuum Tubes This is an inherently high temperature device that controls the electrical current between the electrodes in the vacuum tank. The vacuum tube relies on thermionic release of electrons from the hot filament. They are among the first and oldest high-temperature electronic devices. Although with the invention of transistors in the 1950s, these tubes almost disappeared from the electronics industry, they are still useful in certain cases related to microwave amplifiers, high frequency amplifiers and especially for pressure sensor preamplifier for Venus rovers. The figures below show vacuum tubes and a concept of internal components. For Venus rovers, the use of TVT can be considered because the cathode is designed to operate between 700 and 900°C. Yet these tubes still need to be optimized for Venus' harsh environment, as their use for Venus rovers presents some challenges. Challenges related to packaging, high level of integration, shelf life, power supply, size and weight. The graphs below show the influence of temperature on thermal vacuum tubes. Recent tubes use the cathode of the filament. This is a directly heated tube. The figure and concept below shows a vacuum tube including the heater, cathode, grid and anode. As mentioned earlier, TVT devices can be used for the high temperature pressure sensor amplifier in a Venus rover. The thermionic vacuum tube preamplifier was evaluated at room temperature and 500°C. The results are shown below: Passive devicesResistors: For a Venus rover, resistors are essential requirements for enabling a wireless system at high temperatures. High temperature resistances constitute one of the great challenges of Venus missions and this technology is still in development. Currently HT resistors are capable of operating at +500°C but with a limited lifespan. There are some factors for choosing the best resistor for the Venus rover, such as: Noise Thermal stress Interdiffusion Oxidation Looking at the table, we can see that the Ruthenium Silver and Ruthenium Oxide resistors have the highest maximum operating temperature. Ruthenium oxide also features superior stability, low thermal stress and low noise. But the main problem with these two resistors is that ruthenium is very rare and difficult to find. In this case, the cost of these resistors would be high. So technically we should look for another type of high temperature resistors. On the other hand, we have thin film and thick film resistors. The notable advantage ofthese resistors is that they are based on a ceramic substrate and that they no longer need mechanical fixing. Recently, a new type of thin film nickel-chromium resistors (NiCr) has been introduced by scientists. NiCr resistances are stable at almost 10% at 300°C. They have a high stability rate and low noise (not as good as ruthenium resistors). But the biggest advantage is the lower price. In my opinion, and considering the factors of cost, stability and maximum temperature, NiCr thin film resistors are the best choice for a long duration surface mission on Venus. Capacitors: Besides resistors, capacitors are also key elements of the high-temperature wireless system for Venus rovers. Current capacitors are not ready for a long-term surface mission on Venus. This technology is still in development. Innovations on all fronts, including materials, device design and packaging, are pursued. Before making a capacitor for extremely harsh environment, we need to consider some parameters like capacitance, leakage current, equivalent series resistance, rated voltage, dissipation factor, dielectric absorption and efficiency volumetric or weight. Here we will take a look at some of the famous high temperature capacitors. X7R: Capacity is strongly dependent on temperature. High current leakage at high temperature.NP0: Stable up to nearly 500°C with zero capacitance coefficient. High temperature dissipation problem. Piezoelectric: composition selected to achieve peak capacitance and dissipation factor for specified temperatures. Difficult to implement. Diamond: Theoretically functional up to almost over 500°C with stable and high capacity. Still under development to achieve uniform diamond film and stable metal contacts. Air gap/parallel plate: low capacity, but stable over the entire temperature range. Very large surface capacitors would be necessary. All the capacitors mentioned have a limited lifespan for the harsh environment of Venus, but recently a new design of high temperature capacitors has been invented by scientists. It is known as MIM (Metal Insulator andMetal Capacitors). The MIM capacitor is composed of two parallel plates with a dielectric layer between the plates. A microstrip line is connected to each plate. I think MIM capacitors based on SiC technology are the best choice for Venus rovers. However, these capacitors still need to be optimized due to their limited lifespan. It is expected that by +2020, scientists will be able to manufacture MIM capacitors with a long lifespan. Oscillators: Oscillator is one of the important components of wireless sensor system for signal generation, which is modulated by the sensor and the data will be transmitted to colder environments. , NASA's Glenn team is working on high-temperature oscillators to enable the advancement of SiC devices, as well as for the improvement of passive devices. The figure below shows a prototype HT oscillator that was tested by the Glenn team under conditions similar to those on the surface of Venus. Oscillator with SIC MESFET and capacitors with ceramic chip, spiral inductor and interconnections. Packaging Materials For harsh environments, packaging is required for operation. of sensor and electronics technologies beyond those of ordinary electronics and sensors. For Venus missions, sensors and electronics..

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