Europa is extra than simply one in every of Jupiter’s many moons — it is also one in every of most promising locations within the photo voltaic system to search for extraterrestrial life. Below 10 kilometers of ice is a liquid water ocean that would maintain life. However with floor temperatures at -180 Celsius and with excessive ranges of radiation, it is also one of the vital inhospitable locations within the photo voltaic system. Exploring Europa could possibly be doable within the coming years due to new functions for silicon-germanium transistor expertise analysis at Georgia Tech.
Regents’ Professor John D. Cressler within the College of Electrical and Pc Engineering (ECE) and his college students have been working with silicon-germanium heterojunction bipolar transistors (SiGe HBTs) for many years and have discovered them to have distinctive benefits in excessive environments like Europa.
“As a result of approach that they are made, these gadgets truly survive these excessive situations with none modifications made to the underlying expertise itself,” mentioned Cressler, who’s the challenge investigator. “You’ll be able to construct it for what you need it to do on Earth, and also you then can use it in area.”
The researchers are in yr one in every of a three-year grant within the NASA Ideas for Ocean Worlds Life Detection Know-how (COLDTech) program to design the electronics infrastructure for upcoming Europa floor missions. NASA plans to launch the Europa Clipper in 2024, an orbiting spacecraft that can map the oceans of Europa, after which ultimately ship a touchdown car, Europa Lander, to drill by means of the ice and discover its ocean. However it all begins with electronics that may perform in Europa’s excessive surroundings.
Cressler and his college students, along with researchers from NASA Jet Propulsion Lab (JPL) and the College of Tennessee (UT), demonstrated the capabilities of SiGe HBTs for this hostile surroundings in a paper offered on the IEEE Nuclear and Area Radiation Results Conventionin July.
Europa’s Problem
Like Earth, Jupiter additionally has a liquid metallic core that generates a magnetic subject, producing radiation belts of high-energy protons and electrons from the impinging photo voltaic wind. Sadly, as a moon of Jupiter, Europa sits squarely in these radiation belts. In impact, any expertise designed for Europa’s floor wouldn’t solely want to have the ability to survive the chilly temperatures but in addition the worst radiation encountered within the photo voltaic system.
Luckily, SiGe HBTs are perfect for this hostile surroundings. The SiGe HBT introduces a nanoscale Si-Ge alloy inside a typical bipolar transistor to nano-engineer its properties, successfully producing a a lot sooner transistor whereas sustaining the economy-of-scale and low price of conventional silicon transistors. SiGe HBTs have the distinctive potential to take care of efficiency below excessive radiation publicity, and their properties naturally enhance at colder temperatures. Such a singular mixture makes them excellent candidates for Europa exploration.
“It isn’t simply doing the essential science and proving that SiGe works,” Cressler mentioned. “It is truly growing electronics for NASA to make use of on Europa. We all know SiGe can survive excessive ranges of radiation. And we all know it is stays practical at chilly temperatures. What we didn’t know is that if it may do each on the similar time, which is required for Europa floor missions.”
Testing the Transistors
To reply this query, the GT researchers used JPL’s Dynamitron, a machine that shoots high-flux electrons at very low temperatures to check SiGe in Europa-type environments. They uncovered SiGe HBTs to at least one million Volt electrons to a radiation dose of 5 million rads of radiation (200-400 rads is deadly to people), at 300, 200, and 115 Kelvins (-160 Celsius).
“What had by no means been completed was to make use of electronics like we did in that experiment,” Cressler mentioned. “So, we labored actually for the primary yr to get the outcomes which might be in that paper, which is in essence definitive proof that what we claimed is, in actual fact, true — that SiGe does survive Europa floor situations.”
Within the subsequent two years, the GT and UT researchers will develop precise circuits from SiGe that could possibly be used on Europa, comparable to radios and microcontrollers. But extra importantly, these gadgets may then be seamlessly utilized in virtually any area surroundings, together with on the moon and Mars.
“If Europa is the worst-case surroundings within the photo voltaic system, and you’ll construct these to work on Europa, then they’ll work anyplace,” Cressler mentioned. “This analysis ties collectively previous analysis that we’ve completed in my workforce right here at Georgia Tech for a very long time and reveals actually attention-grabbing and novel functions of those applied sciences. We pleasure ourselves on utilizing our analysis to interrupt new revolutionary floor and thereby allow novel functions.”
Video: https://youtu.be/hKr6uh4k-7g
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Supplies offered by Georgia Institute of Know-how. Authentic written by Tess Malone. Notice: Content material could also be edited for type and size.
