One of Jupiter’s numerous moons, Europa is also one of the most promising places in the solar system to look for extraterrestrial life. Under ten kilometres of ice, there lies a liquid ocean that might be home to life. Despite this, it is among the least hospitable locations in the solar system, with surface temperatures of -180 degrees Celsius and high radiation levels. The development of silicon-germanium transistors at Georgia Tech may make it possible to explore Europa in the upcoming years.
Working with silicon-germanium heterojunction bipolar transistors (SiGe HBTs) for many years, Professor John D. Cressler of the Regents’ School of Electrical and Computer Engineering (ECE) and his students have shown that they offer distinct advantages in harsh environments like Europa.
According to project investigator Cressler, “These gadgets actually endure such harsh conditions due to the method that they’re built, without any alterations made to the underlying technology itself.” You can construct it to accomplish your goals on Earth and employ it in space afterward.
As part of a three-year NASA Concepts for Ocean Worlds Life Detection Technology (COLDTech) contract, the scientists are currently in the first year of developing the electrical framework for upcoming Europa surface missions. In 2024, NASA plans to launch the Europa Clipper, an orbiting spacecraft that will study Europa’s oceans. Later, the agency will send the Europa Lander, a landing craft that would drill through the ice to examine Europa’s ocean. But it all starts with electronics that can function in the hostile climate of Europa.
Researchers from the NASA Jet Propulsion Lab (JPL) and the University of Tennessee (UT) joined Cressler and his students to demonstrate the capabilities of SiGe HBTs for this hostile environment in a work that was presented at the IEEE Nuclear and Space Radiation Effects Conference in July.
Similar to Earth, Jupiter has a liquid metal core that produces a magnetic field and radiation belts of solar wind protons and electrons with high energy. Europa, a moon of Jupiter, unfortunately is right in the path of these radiation belts. In other words, any technology created for Europa’s surface would need to be able to endure both the solar system’s harshest radiation and the planet’s extreme cold.
Fortunately, SiGe HBTs are perfect for this challenging environment. The SiGe HBT nano-engineers a conventional bipolar transistor’s features by enclosing a tiny Si-Ge alloy inside of it. This produces a transistor that is significantly quicker while keeping the economies of scale and low cost of conventional silicon transistors. The performance of SiGe HBTs can be maintained in extreme radiation conditions, and their characteristics improve naturally as the temperature is lowered. They are excellent prospects for exploring Europa because of this unique combination.
Cressler remarked, “It’s not simply doing the fundamental science and showing that SiGe works. Actually, it’s creating electronics that NASA will utilise on Europa. We are aware of SiGe’s radiation resistance. And we are aware that it functions properly in chilly climates. We were unsure as to whether it could simultaneously perform both tasks, which is necessary for Europa surface missions.
To test SiGe in conditions similar to those found in Europa, the GT researchers utilised JPL’s Dynamitron, a device that fires high-flux electrons at very low temperatures. They exposed SiGe HBTs to one million Volt electrons and a radiation dose of five million rads at 300, 200, and 115 Kelvins (200-400 rads is deadly to humans) (-160 Celsius).
What had never been done, according to Cressler, was use electronics like we did in that experiment. Therefore, “we essentially laboured for the first year to achieve the results that are in that paper, which is really clear proof that what we stated is, in fact, true—that SiGe does withstand Europa surface conditions.”
The following two years will be devoted to creating practical SiGe devices, like radios and microcontrollers, that may be deployed on Europa. The ability to use these gadgets in virtually any space environment, including on Mars and the moon, is even more significant.
“If you can build things to work on Europa, which is the harshest environment in the solar system, then they will work elsewhere,” Cressler added. “This discovery connects together earlier research that my team and I have conducted for a considerable amount of time here at Georgia Tech, and it demonstrates truly fascinating and innovative applications of these technologies. We take great delight in utilising our knowledge to forge ahead in fresh ways and open up new applications.
(source : ANI)
