One reason NASA's Mars lander missions have been so successful is the development of silicon-based integrated circuits capable of surviving the Martian environment for years. Now NASA is hoping for similar results for Venus by developing silicon carbide circuits that can withstand the incredibly hostile Venusian conditions for over 520 hours without special shielding or cooling systems.
Venus was once thought one of the two most likely places in the Solar System where life might exist, but the Mariner and Venera space probes of the 1960s and '70s told another story. Instead of the swampy world inhabited by dinosaurs as imagined by sci-fi writers, the unmanned explorers found a planet with a surface temperature of 460° C (860° F), a carbon dioxide atmosphere 94 times has heavy as Earth's, and weather marked by deadly sulfuric acid rains.
Despite these hellish conditions, a series of Soviet Venera missions attempted to land on Venus – many of them successfully. However, "successful" is a relative word. In order to survive the landing and send back data, the Venera landers used massive, specially armored pressure vessels with special cooling systems. None lasted more than 127 minutes on the surface before succumbing to the hostile environment.
According to NASA, even a lander built today wouldn't last more than a few hours. There are many reasons for this, but a key factor is the electronics used by the lander. Just as a Mars lander couldn't survive using the old radio valves or primitive printed circuits of the 1950s, the silicon-based integrated circuits used today can only operate on Venus for a brief time under heavy protection.
NASA's answer is to develop a new electronics technology using much tougher silicon carbide as a base. A team at the space agency's Glenn Research Center in Cleveland, Ohio produced silicon carbide semiconductor integrated circuits, two of which were subjected to a simulated Venusian environment in the Glenn Extreme Environments Rig (GEER).
What the team found was that, without any special protection, the silicon carbide circuits survived for 521 hours, which is a fair advance on 127 minutes. According to NASA, the circuits were still functional after the test. Similar circuits were originally developed to operate inside aircraft engines and had already survived 1,000 hours at a temperature of 482°C (900° F) in the Earth's atmosphere.
"This work not only enables the potential for new science in extended Venus surface and other planetary exploration," says Gary Hunter, principal investigator for the Venus surface electronics development. "But it also has potentially significant impact for a range of Earth relevant applications, such as in aircraft engines to enable new capabilities, improve operations, and reduce emissions,"
The research was published in AIP Advances.
Source: NASA
