The Magellan probe that orbited Venus from 1990 to 1994 was able to see through the thick Venusian clouds. NASA image
Fairbanks, Alaska (KINY) – Earth has earthquakes, Venus has venusquakes. Researchers at the University of Alaska Fairbanks Geophysical Institute, in collaboration with NASA, are helping to create a Venusian seismometer that can operate long enough at that planet’s extremities to provide information about its seismicity.
It is a major challenge. Venus has surface temperatures of 900 degrees Fahrenheit, hot enough to melt lead, and atmospheric pressure 90 times that of Earth, equal to the pressure one mile below Earth’s oceans.
Learning about the seismicity of Venus is a part of NASA’s Seismic and Atmospheric Exploration of Venus, or SAEVe, project. The mission concept envisions two landers with seismometers positioned between 200 and 500 miles apart. The instruments are under development in NASA’s High Operating Temperature Technology program, which seeks to design devices that can operate in the brutal conditions on the surface of Venus.
“Venus is the planet in our solar system most similar to Earth,” said UAF Geophysical Institute postdoctoral researcher Yuan Tian. “Their structures are very similar to structures on Earth, but some structures can only be found on Venus.”
“To better understand earthquakes on Earth, we have to study other planets,” he said.
Venus’s surface is folded and faulted, but the planet does not have plate tectonics similar to Earth’s. Scientists have offered a variety of theories about the processes that shape the planet’s surface.
Tian and colleagues at NASA’s Glenn Geophysical Institute and Research Center in Ohio conducted a series of studies on combined hardware and software approaches to maximize data collection from a Venus seismometer.
Their work was published late last year in the journal Seismological Research Letters. Tian is the lead author. Research professors Robert Herrick and Michael West, both of the UAF Geophysical Institute, and Tibor Kremic of the Glenn Research Center are co-authors.
Research and development of survivable electronics on Venus has advanced to the point where a battery-powered Venusian seismometer is feasible. Design of a prototype is underway through NASA’s HOTTech program.
The longest a surface lander with conventional electronics has lasted on the surface of Venus is about two hours, the research paper reads. Achieving the most basic goal of determining seismicity levels requires the ability to operate over a period of at least days, with more complex goals requiring longer operation.
A seismometer for Venus has to be made of materials that can survive heat and pressure and have a battery that can survive and hold power long enough to collect and transmit data. Solar-powered seismometers are not an option due to the high surface temperature and the limited amount of solar power available relative to the power needed to transmit data.
The seismometer will also have minimal data storage on board to save power consumption, which means it will need to have a trigger that causes it to transmit data to an orbiter as soon as a seismic event occurs.
The seismometer should be programmed to prevent it from being activated by seismic signals caused by the wind. You will also need to differentiate between small but close earthquakes and large but distant earthquakes for which scientists will want data.
It’s a tall order for a lone lander.
To achieve that, Yuan and his colleagues created an operational algorithm that requires minimal internal memory. Includes a ratio based streaming trigger.
When the shaking from a seismic event reaches the threshold based on the ratio, the seismometer will activate for a certain amount of transmission time. This method reduces instances of data transmission of little use to scientists and extends battery life.
The researchers built their transmission algorithm using a nine-day record from a single seismic station in central Alaska to simulate likely seismicity on Venus.
“We define success as triggering as many real events in the catalog as possible without triggering noise,” the research paper reads.
