Space grade electronics and the Venus problem
Published Wednesday 1st May, 2019
Developing space grade electronics is a tough job, but making them robust enough to handle one of the most alien and inhospitable environments known to man is another thing entirely. Venus may be our closest neighbour, but its hurricane force winds, 460°C surface temperature, and atmospheric pressure more than 90 times that of Earth makes it anything but welcoming… and no probe has lasted more than two hours on its surface.
However, over the last few years, NASA and other space agencies around the world have been working to overcome these obstacles, with the hope of developing robots capable of surviving several months on Venus.
Let's take a look at the potential electronics solution to this problem and see where NASA is with its thinking right now.
Testing space grade electronics
In order to survive on Venus, previous mission probes had to be encased in pressure and temperature resistant casings with complex cooling systems, but these all failed quickly and exposed the silicone-based semiconductors to temperatures far outside their normal operating parameters. Instead of attempting to build stronger casings, it seemed more intelligent to try to develop electronic components that could survive without help.
NASA used its Glenn Extreme Environment Rig (GEER) at the Glenn Research Centre to develop and test silicon carbide semiconductors, which it hopes will provide up to 4000 hours of service at 500°C. Testing has shown that a silicon carbide 12-transistor ring oscillator can function in a stable state for 521 hours under the same conditions present on Venus.
This is even more impressive when you hear that the test only ended for scheduling reasons, and the same tech has proven to be effective for thousands of hours in Earth atmosphere ovens at 500°C. These results demonstrate the strides made in developing complex space grade electronics that are up to the task of collecting data for extended missions to Venus and beyond.
NASA's latest ideas on the Venus project
NASA is in no hurry to develop electronics up to the task of extended Venus stays, however, and nothing concrete has been built yet. In fact, they're still openly considering all options – including the outside chance of manned missions!
Clearly, landing humans on Venus is far beyond our scope, but Project HAVOC (that's 'High Altitude Venus Operational Concept') was almost as daring. Using solar-powered airships, astronauts would hover in the upper atmosphere for 30-day missions and record data before returning to Earth. As crazy as this may sound, the upper atmosphere of Venus is much more Earth-like than the inner atmosphere, which made it a possibility. It’s a shame that this inventive idea was archived, as it would have been interesting to study the electronics designed for that mission.
So, with that idea off the table for the foreseeable future, NASA is working on the more sensible option of stronger, more capable robotic probes for future journeys to our nearest neighbour – even though the earliest possible launch date would be 2026.
We're going to keep an eye on this fascinating story because developments in space graded electronics usually have an impact on terrestrial technology, and we’re always looking for more robust and hardwearing solutions.