HOTTech Attempts to Tackle Venus

Specialized test equipment determines how new technology performs in extreme conditions

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High Temperature Operating Temperature Technology (HOTTech) Program; NASA Glenn Extreme Environment Rig (GEER)

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Projects in NASA’s HOTTech program are developing technology that can operate on the surface of Venus for at least 60 days. Previous Venus landers could only survive for a few hours, so extended operation would represent a paradigm shift in lander technology. His GEER chamber at NASA’s Glenn Research Center simulates conditions on Venus and serves as a testbed for materials, electronics, sensors, and power technologies for future long-term exploration.

As far as solar system exploration is concerned, The surface of Venus is inhospitable For technology. The average temperature is around 900°F, which is high enough to melt metals such as lead. The atmospheric pressure is over 90 times that of Earth. And the atmosphere contains highly corrosive chemicals. Previous Venus landers exposed to such harsh environmental conditions could only survive for a few hours. To overcome this challenge, the HOTTech program is developing core technologies such as electronics, batteries, power systems, and actuators that can operate on the surface of Venus for at least 60 days.

The teams working on these technologies have been building and testing them in labs across the United States over the last few years, but ultimately the big question is: How will these technologies work on Venus? That’s it.enter Glen Extreme Environmental Rig (GEER), a nearly 20-ton chamber at NASA’s Glenn Research Center, was designed to simulate conditions on the surface of Venus. This chamber is huge to safely contain the pressure of Venus. The GEER end cap slides open on railroad-like rails to allow for experimental setup. The simulated surface pressure of Venus exerts a force of 2 million pounds. The heater keeps the chamber and everything inside it at an extreme temperature of about 900°F. In addition, GEER can insert and monitor corrosive gases into the chamber and “boost” them as necessary to match conditions expected on the surface of Venus (these gases (It may react with the technology being tested!). Finally, the GEER team incorporated electrical feedthroughs to allow power and electrical signals to be transferred between his HOTTech technology inside the chamber and external test equipment.

GEER Chamber (Image credit: NASA GRC)

Several HOTTech project teams formed a community of practice and collaborated with each other and the GEER team to improve and optimize the technology. The goal is to eventually combine successful individual components to build higher-performing systems. The technologies listed below were recently tested together at GEER to learn how they would perform during long-term operations on Venus.

GEER testing of these technologies was conducted from December 2022 to February 2023. Engineers are still conducting post-test analyzes to assess the technology’s performance, but some promising early results have already been noted.

Gaskets are critical components that seal various mechanical and electrical systems in spacecraft and landers, preventing the ingress of dust, gases, and other contaminants. While developing a power system for a future Venus lander, the Penn State team identified vermiculite as a potential gasket material that could withstand extreme Venus conditions. “Vermiculite is a mineral with excellent thermal stability, a low coefficient of thermal expansion, and excellent resistance to most corrosive environments,” said Dr. Christopher J. Greer, assistant professor of mechanical engineering at Penn State.. GEER testing confirmed this vermiculite sealant’s ability to withstand high pressures and temperatures and withstand Venusian corrosive conditions.

In this recent GEER test, three different groups tested electronic devices packaged by a fourth group in a joint effort. One of his devices was a diamond diode provided by Dr. Nemanich, who is a member of the Arizona State University team. He explains: “A computer-controlled system turned on the diamond diode every hour and recorded the forward and reverse current density (vs. voltage). The figure below shows a composite plot of all measurements over a 30-day period. Throughout the test, the diode exhibits high rectification ratios (forward and reverse current densities), which is consistent with theoretical simulations.” It will be the first demonstration of period-operating diamond-based electronics and provide the foundation for new types of electronics for future missions.

Composite plot of electrical properties of diamond diodes during HOTTech GEER testing. Current-V curves were recorded during the 30-day test, and the color scale on the right indicates the day a particular scan was recorded (Image credit: Dr. Robert Nemanich/Arizona State University)

A notable “first” achieved in the GEER test was the successful operation of electronic memory. This allows scientific data to be stored until it can be transmitted by: Silicon carbide (SiC) electronics. The photo below shows the original state of the memory chip and packaging after the GEER test is completed, as well as a snapshot of the electrical performance during the test. Dr. Phil Neudeck of NASA GRC said: “Although this early prototype chip is only 16 bits, it is the first random access memory ever to demonstrate successful operation for several days while exposed to extreme temperatures, pressures, and reactive chemicals. The surface of Venus. The chip outlasted the test period in the Venusian environment. Such capabilities have proven to be extremely beneficial scientifically on the surface of Mars. It represents a new step towards opening up the world.”

Silicon carbide RAM memory chip (top) and electrical signals (bottom) after exposure to Venus surface conditions simulated in GEER, demonstrating perfect memory operation without protection from Venus surface conditions in GEER is shown. (Image credit: OAI, Dr. Liangyu Chen)

This latest GEER run also tested other technologies. Results are still being analyzed and will be the subject of future presentations and publications. Overall, a wide range of techniques and materials of varying degrees of maturity were given their first Venusian surface exposures simulated by GEER, in some cases. While some technologies achieved a new level of proven maturity, developers of other technologies learned valuable lessons about the harsh environment of Venus’s surface. This collaborative GEER testing effort provided the foundation for future technological advances that will enable long-term missions on the surface of Venus.

Project leader

Dr. Michael Lienhard (GRC), PSD HOTTech Program Director. Dr. Gary Hunter (GRC), HOTTech GEER Coordinator.and his HOTTech Principal Investigator above.

Supporting organization

NASA SMD Planetary Science Division HOTTech Program