Exploring VERITAS, one of NASA’s new missions to Venus

by Haygen Warren

“So we want to look for that chemical fingerprint of water and its effect on the surface chemistry of Venus. We really want to answer this question: are those huge deformed old plateaus (tesserae), are they Venus’s equivalent of continents and thus a marker of the water evolution on Venus?”

Water’s past, present, and future on Venus is another point of interest VERITAS hopes to investigate while in orbit.  “We really don’t know when that atmosphere lost its water. And similarly, we want to look for water coming out of the planet today. Because 30 years ago, when Magellan was in orbit, we thought that a planet’s water came from comets.”

“And we’ve learned a lot about asteroids. We’ve learned a lot about comets in the last decade or so. And we realized that sure, comets definitely deliver water to planetary bodies, but the vast majority of it is coming out of the interior of the planet,” Dr. Smrekar said.

Due to the immense surface pressure of Venus, it’s hard for gases to escape from its interior. So, if water were to be released from the interior of Venus, it would have to make up a noticeable percentage of the magma ejected from the interior of the planet by volcanoes. This same phenomenon occurs in some places on Earth — adding to the list of similarities between the two planets.

“So say that Venus is really releasing Earth-like water from its deep interior. In terms the evolution and in understanding how these two planets diverged, that’s a major, major question,” Dr. Smrekar added. “So that’s one thing we’ll look for.”

Observing active volcanism on Venus is extremely hard due to the environmental conditions surrounding volcanoes, though. “With active volcanism, you have to get really lucky because as soon as those lavas spew on the surface, they crust over. So, within probably a couple weeks of erupting, for a typical flow, you probably wouldn’t see it anymore.”

Sapas Mons. Image composed using data from NASA’s Magellan spacecraft. (NASA/JPL-Caltech)

However, VERITAS teams will be looking for another indicator of active volcanism — lava lake-type surface features.

“Now, if it was like a lava lake or something, where there’s constantly new and bright features, basically a red iridescent glow is what we’re looking for in terms of active stuff. If that’s at the surface and in significant quantities, we’ll be able to see it.”

If VERITAS’ team were to find prominent, active volcanism on Venus’ surface, what might this mean for the overall habitability of of the planet? For this explanation, Dr. Smrekar links back to the idea that phosphine may be present in Venus’ atmosphere.

“In that initial paper, they had said, ‘Oh, Venus isn’t volcanically active enough to possibly produce enough phosphine in that manner.’ And I think that’s likely incorrect. I think Venus is volcanically active enough. The question is, even if there’s enough volcanic activity, where’s that volcanism originating and what’s the chemical makeup of where that volcanism is originating?”

“You need, basically, a reducing mantle to produce phosphine in the interior. And we don’t know what’s going on in the interior of Venus, especially chemically. And it’s hard enough to know [what’s going on] in the Earth. So that’s a very open question for Venus.”

“If we can find lots of volcanism, and we can find lots of water,” Dr. Smrekar added, “that says the interior is not reducing. Because that water wouldn’t be stable if it was. And so that would rule out phosphine coming from the interior of the planet.”

However, scientists know too little at this point about Venus’ surface volcanism rates to make good estimates for potential habitability. To this end, “There are things that we will always have to model with respect to habitability. VERITAS is really aimed at trying to understand the holistic view of habitability. The astrobiologists, the exoplanet study modelers, have kind of put together a list of things that they find compelling about the habitability of Earth. Of course, that’s our reference.”

The VERITAS teams will look for various surface features and processes that affect habitability. For example, they will search for and try to understand plate tectonics, the role of volatiles on Venus’ environment, the catastrophic resurfacing of Venus, why Venus doesn’t have a dynamo, and more.

And VERITAS will not be the only mission studying the past, present, and future habitability of Venus.

DAVINCI, the Discovery program mission selected alongside VERITAS on June 2, will perform a descent into the atmosphere of Venus. During its period, it will sample and analyze the gases it detects and will send back valuable data on the true nature of Venus’ atmosphere. 

Meanwhile, the European Space Agency’s EnVision mission, which NASASpaceflight conducted a similar in-depth introduction for, will use a variety of radars to research the surface of Venus in extreme detail. EnVision is similar to VERITAS in that it will map out the Venusian surface, but unlike VERITAS, EnVision will study specific areas and surface features as well as the overall surface environment.

Dr. Smrekar sees the three missions, set to operate around Venus simultaneously, working together in a similar manner to Mars orbiters and landers. “Mars has this very successful model of orbiters and landers, and we’ll be able to do the same kind of thing because with the global data sets that we provide, we provide the geologic context to understand the location that DAVINCI will probe,” Dr. Smrekar said.

For the DAVINCI mission in particular, although the timelines are still being determined, VERITAS could provide context to certain areas of interest where DAVINCI might want to enter.

“The timelines are still being ironed out in detail, so we probably can’t really help them choose their landing site. But we can say how similar is this site to other sites around the planet and provide the bigger geologic context to interpret the data that they will acquire.”

“You know, if they’re particularly focused on going to Alpha Regio, one of the tessera plateaus, we’ll get compositional data for that and be able to say, ‘yes, is it in fact granitic as we anticipated.’ ‘How similar is it to the other tessera plateaus?’ So we’ll provide that as well as topography to help them fine-tune their mission.”

The DAVINCI mission could also help provide data for VERITAS that the spacecraft can use when making scientific observations.

“We’ll be able to see in a visual image this location where they’ll (DAVINCI) be coming down. And that’ll help us interpret our radar data more precisely as well. And they’re going to be getting temperature and pressure near the surface, and that’s something that we use to put into the data reduction for our surface emissivity. So that’ll be valuable to us, too.”

As with every mission, VERITAS has a set of stated goals and objectives to accomplish during the mission’s lifetime. However, there are always “would be nice” elements to missions.

The first color images from the surface of Venus, taken by Venera 13 on March 1, 1982 just to the east of the eastern extension of Phoebe Regio. (Credit: Soviet Academy of Sciences)

“For me, personally, I’ve been studying these features called coronae my entire career. And they’re basically small-scale, well, I think they have multiple origins, honestly. And they’re arguably found only on Venus,” Dr. Smrekar said.

“The range of features that we see is unique to Venus. And there’s like 500 of these features around the surface. To me, they have always been super-interesting because we don’t see them on the Earth. So that’s telling us something fundamental about the differences between Venus and Earth.”

VERITAS is currently expected to launch in 2028 on a yet-to-be-chosen rocket from the U.S. After liftoff, it will coast through space for several months before entering orbit around Venus, where it will perform its observations.

“I’ve been studying Venus my entire career, but I think it’s going to be super-important to get these really foundational datasets for Venus in the context of trying to understand all of the rocky planets of the solar system and elsewhere,” Dr. Smrekar said.

“So it’s going to help us in understanding theories about Mars, Mercury, the moon. It’s not only the Earth. I think we’re going to learn about how rocky planets form. So it’s just the kind of missing link in understanding what’s going on in our solar system’s evolution.”

(Lead image: VERITAS. Credit: NASA/JPL/Caltech)

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