Last week, our home institution of the Planetary Science Institute (PSI) sent out a press release about a trio of papers about Venus, including one that was published in Science Advances on Friday. The other two papers were published in the journal Icarus and in Geophysical Research Letters. PSI’s Darby Dyer is the lead author on those last two and a co-author on the Science Advances paper.

Here are the basics: Venus is covered in very thick clouds of carbon dioxide. This cloud layer makes it incredibly difficult to get any information about the surface of the planet, as most visible and near-infrared light cannot penetrate, so we cannot get spectra of the rocks on the surface. A few Soviet landers managed to acquire some data back in the 1970s, and the Magellan mission obtained some radar data.

It’s not a completely hopeless situation, however. There are some tiny windows in the near-infrared at about one micron that can penetrate the thick clouds. So let’s send an orbiter! But wait. The question then becomes how will we know if the data we acquire through those windows with that expensive orbiter is accurate when we’ve not sampled data in this fashion before. Laboratory work to the rescue.

Dr. Dyer worked with a team out of the German Aerospace Center Institute of Planetary Research to set up a Venus chamber, where they could work with rocks in a similar high-temperature environment to that of Venus and acquire spectra. These spectra made it possible to understand what the composition of a variety of igneous rocks would look like as sampled by a Venus orbiter. The data was compared to spectra taken with those same Soviet landers and found to be a match.

Now we can plan for missions like VERITAS and ESA’s EnVision to include instruments that can perform the six-wavelength spectroscopy tested in the lab. And we can even set up machine learning algorithms in advance to analyze the data from orbit since we already have a dataset to compare to. Very exciting prospects indeed.

More Information

PSI press release

“Deriving iron contents from past and future Venus surface spectra with new high-temperature laboratory emissivity data,” J. Helbert et al., 2021 January 15, Science Advances

“Surface weathering on Venus: Constraints from kinetic, spectroscopic, and geochemical data,” M. Darby Dyar et al., 2020 October 6, Icarus

“Probing Venus Surface Iron Contents With Six‐Band Visible Near‐Infrared Spectroscopy From Orbit,” M. D. Dyar et al., 2020 October 29, Geophysical Research Letters