Tartu scientists presented an instrument for measuring the acidity of the clouds of Venus

It has long been assumed that the atmosphere of the nearest planet to Earth is sulfuric acid-rich and unsuitable for life. New models suggest the situation might not really be that simple. A sensor developed in Tartu may soon shed light on this exciting issue.

Recent data suggests that, in addition to sulfuric acid, neutralizing substances may also be present in the atmosphere of Venus, and complex chemical cycles may occur in the clouds, which is why the acidity level of the droplets of the clouds may vary significantly.

In order to verify the hypothesis, measurements have to be be carried out, and this is where scientists from Tartu lend a helping hand to space research. A special issue of the scientific journal "Aerospace" devoted to the clouds of Venus has just been published. There they introduced their sensor prototype.

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Head of Space Technology Department and Associate Professor in Space Technology in Tartu Observatory, Mihkel Pajusalu hopes to soon send the sensor presented in the article to Venus: "The first probe of the mission series will fly next year, we hope to send our sensor on the way with the second mission, which will launch in 2026."

Laila Kaasik, the first author of the article, got involved with the project by chance: "Mihkel, whom I knew from conferences, wrote to me that they had an astrobiology project and invited me to do some laboratory work as I am a biologist."

The field of research intrigued and the collaboration went smoothly, and Laila abandoned the subject of their master's thesis to devote their full attention to the Venus Clouds project. Under the supervision of Mihkel Pajusalu and Angela Ivask, they defended their master's thesis a few months ago with the title "
Prototyping an acidity sensor to research habitability of the clouds of Venus".

"I worked on experiments to find how to bind the pigment to the matrix and actually get the sensor to work. At the same time, I was also looking for tools that would be good to do all this," Kaasik describes the multifaceted challenge.

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The pigment used in the experiments is fluorescein, which glows under a UV lamp. "To bind it to the matrix, we used polyvinyl alcohol, which keeps the pigment in place. It is important that the layer applied to the glass is thin and on the same size scale as the cloud droplets in the atmosphere" Laila Kaasik describes their work.

The article "Sensor for Determining Single Droplet Acidities in the Venusian Atmosphere" published in the journal Aerospace can be found on the website of the publisher MDPI.

This article was published 14 October 2022 in Novaator.