You might wonder why Mars gets all the interplanetary attention when Venus, our sister planet, is actually closer. Well, the hellish orb has the hottest surface in the solar system, hotter even than Mercury. Combined with its dense, caustic atmosphere, none of our computers can handle Venus for more than a few hours. Now, scientists think they have come up with a solution.
NASA researchers developed a new computer chip and tested it without any cooling or protective packaging in a high-pressure, high-temperature environment like the surface of Venus — and it worked. Humans haven't sent a lander to Venus since 1982 (that Russian lander lasted just over two hours) although NASA could launch a rover in 2023, according to Forbes. That visit won't happen unless NASA has a computer chip that can withstand the planet's 450-plus degree Celsius environment.
"If you look at Mars missions, there've been rovers on the surface getting all sorts of scientific data," Philip Neudeck, electronics engineer from the NASA Glenn Research Center in Ohio told Gizmodo. "That dataset is totally missing from Venus, and that's because the electronics don't function on Venus." And the planet has lots of features of interest to us Earthlings. For instance, its geological processes and greenhouse gas-loaded atmosphere could help us better understand processes on our own planet, according to reports compiled by the study's authors.
To understand how to build a Venus-hardy computer chip, we need to understand a little about semiconductors and transistors. Semiconductors are metals that current passes through less easily than regular conductors. You can change the electrical conductivity of semiconductors, which means they're useful as transistors. Transistors are like little gates in the current's path, or the circuit, that open and close based on an input current. Microchips, the backbone of computers, are just all the parts of the circuit like wires and transistors etched into a piece of semiconductor.
Neudeck explained that the most important challenges for a chip on Venus to overcome are the temperature and chemically-reactive atmosphere. Most chips are made out of silicon, but at high temperatures it starts behaving like a regular conductor instead of a semiconductor. Neudeck's chips are silicon carbide instead, which maintain their good ol' semiconducting properties. The team also ensured the interconnects — the wires connecting all of the pieces of the chip — wouldn't fry by using exotic materials like tantalum silicide, among other challenges.
Closeup of he integrated circuit, before and after entering the GEER chamber (Image: NASA)
The researchers created special chips that let out an electronic signal, and put their setup into NASA's Glenn Extreme Environments Rig or GEER, a toxic high pressure cooker that can recreate Venus' atmosphere. The chip survived and continued to function even under the recreated Venus atmospheric conditions for over 21 days. They published their results in the journal AIP Advances.
It's awesome that these chips worked, but they're definitely not ready for primetime yet. As of now, the chips only have 24 transistors on them — comparable to much older microchips rather than those found in modern computers. "We're back to the very early 1970s on Moore's law in terms of the complexity of the chip," said Neudeck. But he already has a 100-transistor chip in the wings, and scientists have already explored the solar system with less-complex chips. Plus, aside from the computer, scientists still need to design the remaining pieces of the Venus-faring rover.
But Neudeck is just looking forward to getting these computers onto a Venus mission. "No one has ever made circuits run in this environment at this temperature," he said. "It really opens up a whole new way of doing Venus missions."