Europa is extra than simply certainly one of Jupiter’s many moons — it is also certainly one of most promising locations within the photo voltaic system to search for extraterrestrial life. Underneath 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 probably the most inhospitable locations within the photo voltaic system. Exploring Europa may very well be doable within the coming years because of new purposes for silicon-germanium transistor know-how analysis at Georgia Tech.
Regents’ Professor John D. Cressler within the Faculty 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.
“Because of the method that they are made, these gadgets really survive these excessive situations with none modifications made to the underlying know-how itself,” stated Cressler, who’s the venture investigator. “You may construct it for what you need it to do on Earth, and also you then can use it in area.”
The researchers are in 12 months certainly one 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 finally ship a touchdown automobile, Europa Lander, to drill by way of the ice and discover its ocean. However it all begins with electronics that may perform in Europa’s excessive setting.
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 setting in a paper offered on the IEEE Nuclear and Area Radiation Results Conventionin July.
Like Earth, Jupiter additionally has a liquid steel core that generates a magnetic discipline, 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 know-how designed for Europa’s floor wouldn’t solely want to have the ability to survive the chilly temperatures but additionally the worst radiation encountered within the photo voltaic system.
Happily, SiGe HBTs are perfect for this hostile setting. 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 value of conventional silicon transistors. SiGe HBTs have the distinctive potential to take care of efficiency underneath excessive radiation publicity, and their properties naturally enhance at colder temperatures. Such a novel mixture makes them splendid candidates for Europa exploration.
“It isn’t simply doing the fundamental science and proving that SiGe works,” Cressler stated. “It is really creating 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 might do each on the identical 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 finished was to make use of electronics like we did in that experiment,” Cressler stated. “So, we labored actually for the primary 12 months to get the outcomes which might be in that paper, which is in essence definitive proof that what we claimed is, the truth is, 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 may very well be used on Europa, equivalent to radios and microcontrollers. But extra importantly, these gadgets might then be seamlessly utilized in virtually any area setting, together with on the moon and Mars.
“If Europa is the worst-case setting within the photo voltaic system, and you’ll construct these to work on Europa, then they’ll work wherever,” Cressler stated. “This analysis ties collectively previous analysis that we now have finished in my group right here at Georgia Tech for a very long time and reveals actually fascinating and novel purposes of those applied sciences. We pleasure ourselves on utilizing our analysis to interrupt new revolutionary floor and thereby allow novel purposes.”