Jim Skinner

Intro:

Jim Skinner leads Astrogeology's Planetary Geologic Mapping group. He was a key author of the best known global geologic map of Mars and the special Northern Plains map. He leads the efforts to maintain a standard Planetary Mapping Protocol and is the supervisor of the USGS-NASA Planetary Geologic Mapping Program.

Hargitai:

Were there any special difficulties in making the uniform global map of Mars?

Figure 1 Tanaka, K.L., Skinner, J.A., Jr., Dohm, J.M., Irwin, R.P., III, Kolb, E.J., Fortezzo, C.M., Platz, T., Michael, G.G., and Hare, T.M., 2014, Geologic map of Mars: U.S. Geological Survey Scientific Investigations Map 3292, scale 1:20,000,000

Skinner:

Yeah, so it was an interesting project because it was five years, and typically NASA proposals are three years long. And so, that caused a little bit of an issue just from a logistical standpoint. The other part of the logistics there was having multiple mappers on an area, and this area being the whole of Mars. And some of those mappers were in the building, and some of them were not. That was a challenge. The way we subdivided it was, people were assigned certain physiographic provinces. So I, for example, was assigned everything from the lowlands through the highland-lowland transition into Terra Cimmeria, and then kind of the center of the highlands. And so, other people were assigned Tharsis and the Tharsis volcanoes.

Hargitai:

You had this because you had the experience from the north polar…

Skinner:

Yeah, so what Ken tried to do was to identify what people had experience in and what their interests were, and assign them for those regions. Which is great, but trying to bring multiple people together with different methods inside and outside the building was a challenge, a significant challenge. And you have people that are mapping–there's always the quintessential lumpers and splitters in mapping, and there was no way to try to get that reconciled along the way. And so, it was very difficult. Corey Fortezzo was actually the one that did it, and he's here at the USGS. And he was the one that had to go through and amalgamate everything. And so, that was one challenge just from a logistical standpoint. And that's a very typical thing. We talk about geologic mapping and the logistics of geologic mapping. That's typical.

Hargitai:

Was it done in GIS?

Skinner:

So it was done in GIS. We prepared a control package and distributed it to everybody, and then they would periodically give them back to us, Corey. And Corey would amalgamate them. And then, the last year and a half or so, we cut everybody off from the mapping. And then, it was between Ken, and Corey, and me, and we would look at everything in a large format, and we would make those tweaks. And we would talk to people about it, but we would be doing all the mapping on our side. And so, we kind of had three years where everybody was mapping together and sending in periodic updates, and then the last two years, we cut it off, and we were doing the updates because it got to be too unwieldy to try to change the contacts, and the units, and all of that.

So we learned a lot. I learned a lot, just from the execution of the maps, and how that works, and using multiple people. We're implementing some of that now, some of the revisions of that when we start talking about lunar mapping and trying to get the community into mapping the moon with multiple datasets across multiple people and institutions across multiple scales. And so, that's a challenge, and that's something that NASA really hasn't recognized yet is, like, what it means to make a map and the logistical challenges of that. It was also interesting for that product because it was basically the third global geologic map of Mars. There was Mike Carr's map that was Mariner-based, and then there was Scott et al, Scott, Greeley, Ken, multiple folks there, and John Guest was one of them. And that was the Viking-based maps. And so, this was kind of post-Viking.

And there was a lot of interest and maybe even some consternation in the community about why we needed this map because the scale–the original Mariner map was one-to-25-million, the Viking maps were one-to-15-million, and this map was one-to-20-million in Mollweide projection or something that was similar to Mollweide. And people did not quite understand what the intent of it was and why we needed another map. They were very used to and familiar with the I-1802, those Viking-based maps. And so, it took a little bit of sales to have people understand why another map was needed, that it wasn't replacing the map, that it was augmenting and helping describe things in a different way. That was a little bit of an interesting thing. We still are answering questions about why there's a new map for Mars.

Hargitai:

What's the most important argument here?

Skinner:

The most recent global map was made to be more of a product for all people, not just scientists. And so, it was a way to homogenize everything and show a modern view of the geology of Mars on one map sheet. The 1802 Viking-based maps were on three map sheets, so the western hemisphere, the eastern hemisphere, and then the poles. Which is fine for us, that deal with them all the time, for researchers. But it's not necessarily an easy product to consume for the general public. And so, this was a way to make a product that was an updated geologic map that could answer some questions and put everything into one picture for the science community as well as the general public.

Hargitai:

Was there any conceptual shift from previous maps in defining the geological units?

Skinner:

Yes, there were some. Because at that point, we had some of the thermal data from THEMIS, so that became a really good useful base for us, being able to show daytime and nighttime differences in thermal inertia qualitatively. Because at this point, now we're dealing with the entire body, and therefore we're dealing with the entire dataset that goes with Mars. And so, it was not realistic for us to be able to use all the data for all of Mars, so we kind of had to pick and choose. In the end, between topography supplied by MOLA and the thermal inertia data supplied by THEMIS, daytime and nighttime, those were the ones that really helped. And so, that helped us refine how we were describing unit boundaries, trying to get a little bit away from pure geomorphology into something that is a little more–of course, geomorphology drives unit definitions on non-terrestrial bodies. That's all we have to go on.

But past mapping was a little more focused on a Hummocky unit, a groove unit, and using these terms. And so, we were trying to get away from that a little bit and use more terms that were terrestrial-like and using the geography and physiography of Mars to call things like the Nepenthes unit and the different kinds of Cimmeria units. Another thing we did, and this also caused a lot of problems, is that we tried to use the period and epoch in the unit label, so you'll see a mA, so middle Amazonian instead of just Amazonian, which we thought was a good way to try to constrain and have everybody understand when the units were being emplaced. And I think it does, it but also causes a lot of issues because people don't understand why we were doing that.

Hargitai:

Did you use crater-counting for the age definition? And was it different from the previous methods of maybe a stratigraphic definition?

Skinner:

Yeah, so the stratigraphy didn't change that much as far as the definitions and the boundaries between the periods and the epochs. We had our colleagues in Germany doing some absolute model age determinations for tight localities, and that was actually presented in the map pamphlet in the very back. It shows a tabulated four or five pages of all the different areas that we counted. So that was in there. And it didn't change necessarily, but it helped to pin things down as far as, like, the different units. And you'll see, too, that the units–typically in geologic maps for multiple bodies, including Mars, the authors will want to stretch the–in the correlation of map units, where we show where the position of the unit is and when it was deposited or formed, people will want to stretch the boxes vertically, like, the top and the bottom of the box, to try to fit with the crater counts.

And sometimes they will over-rely on the crater counts rather than the cross-cutting relationships. And the cross-cutting relationships are more likely to be correct than model ages for rocks that are basically pinned to the moon, right? For rock samples from the moon. So there's complications from the crater counts. But yes, that map relied on both relative-age crater counting, so size frequency distributions and relative densities, as well as absolute model ages from our German colleagues, who tend to be pretty conservative with applying those numbers. And so, we felt pretty good about that. But you'll see on the correlation of map units on the global map that they conform, the units conform to boundaries, and so that was kind of a way to say, "We don't really understand where these are, but we're kind of using these units to set the beginnings and ends of boundaries chronostratigraphically.

Hargitai:

Moving to the northern plains mapping. How does it fit the series of different maps published by USGS? It's not part of the systematic mapping, not a landing site, but it's some unique...

Figure 2 Tanaka, Kenneth L.; James A. Skinner, and Trent M. Hare 2005, Geologic map of the northern plains of Mars, Scientific Investigations Map 2888

Skinner:

Yes. And so, that one was interesting because from the Viking-based maps–and Ken spent a lot of time in and around the northern plains of Mars when he was mapping for the Viking-based maps. And so, we got funded right when–Ken got funded when MDAP–right when MGS started acquiring data. And so, this was a longer-lived project, too. But the point there was to focus on basically what is everything that's downslope on Mars, or the majority of it, to capture all the materials that were being shed into the northern plains. The only other basins that are there that are capturing sediment like that are Hellas and Argyre. But everything else is presumably moving into the northern plains. So it was a way to capture that. It did not conform to any kind of quadrangle boundaries, but it wasn't the first one. There's a Chryse map by Sue Rotto and Ken Tanaka, and that one also did not conform to…

Hargitai:

On a separate sheet [?].

Skinner:

Yeah. And so, it kind of was capturing that circum-Chryse area. I find that that's really interesting and relevant these days because the time for quad-based mapping is kind of passed now. With the ability to have multiple datasets and be able to display those at multiple resolutions in the GIS, now we're not really as restricted to those boundaries. And so, most of the maps that are getting funded these days either use the boundaries of quads on Mars or the moon arbitrarily, or they take multiple ones and kind of stick them together. Like the Nepenthes map that we published is actually nine MTM, like, 500,000 scale quads all stuck together. So that one, the northern plains one, was testing out different approaches.

Not only was it focused on the northern plains and everything that is feeding into the northern plains, including the circum-Chryse outflow channels, the rugged landslide, and mudflow deposits that are coming from the western slopes of Elysium Mons into Utopia, as well as the lava flows that are coming out of Cerberus Fossae and Cerberus Rupes into Amazonis, and then some of the circumpolar materials. So it was a way to capture all of those kinds of things together. That was interesting. Whenever we're doing mapping at the USGS, we're trying to figure out, "Are there better ways to do it?" And so, we'll test different things. For the global map, it was testing, for example, the use of the mA, so the labels and the symbology. For the northern plains map, we used two different things. One was a color ramp, and so trying to make it be that if you have a spectrum of colors, that the spectrum of colors will more or less overlap with age.

And so, things that are on one side that are redder and browner tend to be older, and then as you move through that spectrum, they become younger. Implemented with various success. And then, another thing that we used was this kind of small-cap identifier in the unit label to show where the units were grouped, so physiographic provinces. So Utopia units, and so we'd have a lowercase u that would indicate that that is a physiographic province. In that case, we also were trying to get away from pure morphology and talk about regions, and putting into the lexicon the use of physiography instead of morphology for the definition of geologic units. So we had Utopia Planitia 1 and 2 units, and the Tinjar Valles A and B that were coming from Elysium. So we're trying to give it the geographic and physiographic names and get away from the pure morphologies, the knobby [?] units, modeled, that kind of thing.

Hargitai:

Isn't that how it happened to the moon? Because the physiographic map of the moon, that's the '61 map [Engineer Special Study of the Surface of the Moon, Physiographic Divisions of the Moon, 1961], was never used–those terms were never used again in later maps.

Skinner:

No, and so that's something that we need to think about. Every body is a little bit different, and with how the geologic processes are taking place and how we document those processes. The moon's interesting just because that was a place that Shoemaker, and then Wilhelms, and everybody else was focusing on and trying to figure out whether they can do this style of mapping. And so, we're at a place now where we're revisiting those products and seeing, "How can we change them? Do we need to change them?" A lot of the mapping that they did is really good, and so even with new datasets, it doesn't change that much. That's a testament to the mappers themselves and the fact that they were–terrestrial mappers tend to do better with planetary mapping than people that are planetary scientists who have never done field mapping. This was something that Wilhelms recognized in one of his documents that I quote all the time. Wilhelms noted that in a footnote, and he didn't mince words about it. He said, "The best mappers are terrestrial mappers," and that they have a better understanding about what it means to make a geologic map. And we still find that to be true now. It doesn't mean that people can't do that mapping, it just means that they have a better understanding about why they're making the map and being objective about it.

Hargitai:

I would jump to the personal one because you were first–you made marine maps at university, and then you moved to Utopia. So what was behind moving to planetary from terrestrial for you?

Skinner:

So when I graduated with my undergraduate degree, I worked offshore. I worked in the oil industry for a couple years on a boat doing seismic work. My degree is actually in marine geology, marine and coastal dynamics. And I always thought that I would be in coastal restoration, living on a boat somewhere, and fixing and hardening the beaches, and helping preserve the landscapes on the coastal areas. Came to school, and it was right where MGS flew. I worked in oil for a little while, then worked in environmental for a little while. It's kind of the two things that you do with a geology degree, right, is oil and environmental. I liked the offshore work. I didn't like the oil work. I didn't like the environmental work either. Came back to school, and it was right when MGS flew.

And then, I started volunteering up here. I started here as a volunteer with Ken. And Ken and Trent basically threw a bunch of data at me to see if I could survive, and I enjoyed it. Making maps was something that always resonated with me. When I give talks now, I talk about, "When I was a kid, three things that I always did was"–our house as on an eroded granite intrusion. So behind our house, in the red dirt, we could pull out books of mica. Like, really thick, big pieces of mica. So I was always interested in geology. I had a mineral gem book, and I'd walk around and look for minerals, convinced that I was going to find something that was really valuable but never finding that.

We would also make maps of our neighborhood. And so we would make these products and, like, all pretend like we were on a treasure hunt. And so, we would make big physical maps of our neighborhood. And then, I always enjoyed space. Back when we used to have encyclopedias, and the S volume was so big it got split into two. And the second one was Sp- to Sz-, I guess, and Sp- starts with space. I remember opening that up and seeing the Apollo flight routes, and the astronauts, and all the things they were doing. So between those two things, I feel like I'm doing what I was supposed to be doing, what I enjoyed as a kid, is now making these maps.

So that switch from terrestrial mapping and understanding different datasets, being in the field, the stressor environments, living offshore when I was working offshore, I think fits really well with this work, especially the field work that we do now and considering what we're doing for astronaut training, and understanding what they're going to be going through, the stressor environments that they're experiencing. So I think that we have a–not just making the maps but helping understand how the maps are made, how to be objective, how to say and describe something correctly without having to overdo it.

I think a lot of times when we see maps that are being manufactured from some of the community members, it's natural for them to over-interpret. And our maps have to be very objective. It's like, "This is what we see. This is what we interpret. But this is how we describe it and how we see it," and try to do that objectively. So that kind of thing, and then convincing flight directors and astronauts to understand that part of it when they go to moon has been one of the highlights of my job, at least for the past five or six years, is making that jump and then convincing other people that it's important to do the mapping.

Hargitai:

How different the maps will be for the astronauts compared to Apollo, the paper maps?

Skinner:

Yeah, so they'll be the same. So Apollo did a really good job of doing these multi-scale, like, the nested maps. And so, they were even down to 1 to 5,000, in some cases, 1 to 10,000, depending if they were open file reports or preliminary products. But 1 to 5, 1 to 10, 1 to 50, 1 to 250. And so, they really understood the need to put things into context. So there will be a similar approach, I think. And then, what will happen that didn't happen then, because we have far more data and a better understanding about how to make maps, it's important for us to understand that a lot of the maps that we make for Mars, the global geologic map of Mars, and the geologic map of the northern plains, those are made for fundamental science, basic understanding of the geologic processes, the context, so that we understand better about the different kinds of processes that might've acted.

They're not made for exploration because the scale is inappropriate for that. So the maps that need to be made for Artemis 3 and beyond, or anybody that's going to the moon, will need to be more applied science maps and integrating hazards, viewsheds, traversability, resources, whatever the resources are, geologic units, thickness of regolith, anything like that. That's all still geologic mapping. And the terrestrial USGS does a lot of this work already. And so, we've been talking to folks out of Reston and Denver about how they make these kinds of products.

Hargitai:

Engineering geology.

Skinner:

Engineering geology and applied science geology, yep. And so, it's understanding what can you see, understanding who all the stakeholders and users are for the product. Because it's not just scientists, it's engineers, it's flight directors, it's crew. When they go to the moon, the way we've been testing it with NASA is that they will have a map book with them, and the map book will have copies of the maps in different kind of stages. So we're trying to determine, "What do they need to see when they're out there? Grids, viewsheds." And Apollo did some of this, but we're adapting what we've done on Apollo and trying to update it with new data and new perspectives.

Hargitai:

So going back to the maps, you also did Venus mapping. How different Venus is from a mapping perspective?

Figure 3 Dohm, J.M., Tanaka, K.L., and Skinner, J.A., 2011, Geologic map of the Metis Mons quadrangle (V–6), Venus: U.S. Geological Survey Scientific Investigations Map 3158.

Skinner:

Venus is interesting. And in that project, I was not the lead. It was James Dohm and Ken were both the leads on that. And that was interesting because James had done a lot of–he's very detail-oriented, he's very structure-oriented. And that's what Venus is. So most of the maps you'll see for Venus, depending on who's mapping it, will have a tremendous amount of features that are mapped, like, structures that are mapped. Others, maybe less so. But it being a tectonic body, it's completely different. And being able to understand the age relationships on Venus is problematic because we can't assume that all the old, really fractured terrains like the Tessera are all the same age. You can assume that, but there's some critical problems with that, so it's not quite clear what that means. And it's a big debate within the community. I don't want to be a part of that.

I like to watch the two camps debate this. But it is true that if you map all the Tessera as the same age and the same thing, it'd be like mapping the Alps and the Himalayas as the same thing because they are tall, and high-standing, and above everything else. And you'd map all the coastal plains and lower areas in North America, the Amazon, and across China as the same thing. Just because physiographically, they look the same. And there's not a whole lot of cross-cutting relationships you can get on Venus that you can on some other bodies, and you're lacking the impact craters, so you can't do that kind of relative age assessment. It's a really complicated body, and every quad on Venus seems to be a little bit different than every other quad, and there's no really good answer on whether you can put that together into a global map like has been done by Jim Head, and Misha Ivanov, and those folks, who have put that together. But you can argue whether that's appropriate or not. It's an interesting project.

Hargitai:

So the mapping protocol [Skinner, J.A., Jr., Huff, A.E., Black, S.R., Buban, H.C., Fortezzo, C.M., Gaither, T.A., Hare, T.M., and Hunter, M.A., 2022, Planetary geologic mapping protocol—2022: U.S. Geological Survey Techniques and Methods 11–B13, 28 p., https://doi.org/10.3133/tm11B13.]. Can you pinpoint some major points on the evolution of the protocol? So what elements you added that were not there before.

Skinner:

Yes. And so, the protocol, which we published–well, one was a white paper that was kind of unpublished, and then the last one was published last year as a techniques and methods paper. That protocol was intended to help give the authors full knowledge about what they're getting ready to get into. So before they even propose, if they can see this document and see all the different levels of detail that need to go into the map preparation. It's to have the community have a full understanding about what it takes to create a geologic map. Because I think often, not just authors but NASA program managers as well think that it's something that just happens, that it's pretty easy to do. And it's not rocket science, but it's very tedious, and it requires some level of attention, just like every other discipline in planetary science and science in general. It's its own thing.

And so, the protocol had multiple purposes. One was to convince the authors and NASA that there is a process, and it's very long and detailed. And so, if you're going to propose to do this, you need to be prepared to take it all the way. The second thing was to keep the maps from languishing, so to put them on a time scale and help people understand when they can complete these maps and what would be expected of them. Lots of the maps before this protocol had been out there for 20 years and had never been submitted. The money had run out, new data had come in. And so, the authors were feeling like they always wanted to do it but didn't have the time, now didn't have the money, now there's new data. And so, us as USGS had a backlog of maps that were not being submitted. We had to go through and talk to everybody and say, "Are you going to submit these maps? Take that back so we don't have that burdening us."

It allows us to focus on maps that are more timely, are going to get out there sooner. And it helps with NASA so that they can track what projects are out there and which ones are actually going to be coming in. So it was helping with that. I think that it helps for everybody to see the different levels of detail and what the expectation is, and help them get a timeline that works for them. We have timelines so that when we conduct a review and give it back to them, there are expectations of the amount of time that it's going to take when they owe it back to us. And if they don't give it back to us within four months, then they are technically in a delinquency stage. So it helps speed things up so that NASA's getting their project sooner rather than later.

Hargitai:

As far as you can remember, how GIS became part of the mapping process?

Skinner:

Yeah, so Trent Hare would be the one to talk to about that. When I started volunteering here in '99, I didn't know GIS. ArcView and ArcInfo were the Esri services that were being provided. Trent was the one that was starting to recognize the importance of this for the planetary mapping community specifically. And so, he was working with Ken quite a bit. The first map that was published in GIS was James Dohm's Thaumasia series of maps. And so, for me, it was something that was just–I never knew the before times, I just knew GIS mapping. But I have seen a giant progression of what GIS can do and the amount of data that's available for us to do this work. So it is required in this protocol. Maps are required to be in GIS, and that's so that they can create them efficiently and that the data can be used by as many people as possible. Now that maps are required to be submitted, and reviewed, and posted in GIS, we have a backlog of all the old maps that were not done in GIS. There's 240-some odd maps. We're going through, and digitizing all those maps, and turning them into GIS so that they are available.

Hargitai:

As an interactive map?

Skinner:

Yeah, so that's one part of it. When you go to the website to download the map, there will be a link to the GIS, and there will be a link to the interactive maps that allow people, not just scientists but anybody, to explore the maps and understand what they are.

Hargitai:

Traverse planning. What's the evolution of traverse mapping methodology from the beginning to now?

Skinner:

Yeah, so I don't know historically. I know what was done for traversing for the Apollo missions and the J missions, and what they had, an LTV. I'm not the person to talk about the history of it. What I can speak to is how I think that we need to be doing this moving forward and what traversing means, and how specifically we would use the geologic maps to help with traversing. Because traversing often is done as an engineering exercise. It's how to safely get somebody from one place to another, which obviously is critical. But there's also the element of, "How can we maximize our science observations along that traverse?" For Artemis 3, the traverses by foot will be very controlled. There will not be a lot of diversity that happens, not a lot of decisions. It will be around and back.

For future missions, there will be more autonomy with the crew to make decisions about where they go and why they go there. But traversing should be able to help account for that, understanding that A, B, C, D along my traverse, I might find out something about station B when I go to A. That means that I don't need to go to B anymore at all. So skipping that. And it's this whole concept of–there's a paper that was written by Jack Schmitt and Kip Hodges, and they talk about a term that they bring up, it's called flexecution. It's an excellent paper, and we talk about this when we do our astronaut training, is flexecuting.

When we're walking around, doing mapping in the field here, you are making decisions all the time about where you need to go, understanding about the terrain, understanding where the car is, understanding when you need to take lunch, understanding that there's a storm coming in. You're always changing based on the conditions on the ground as well as the answers that you're trying to seek. And so, every observation that you make is going to change your traverse plan. We're trying to figure out a way that will computationally integrate and re-rank sites, both engineering constraints and science constraints, couple those together that will push a traverse to maximize science, to give you that maximum return.

Hargitai:

Our geologists are going to be communicating with the astronauts directly from the Earth?

Skinner:

Well, for Artemis 3, they will be communicating, and they will be asking questions, but there will be very little re-planning that happens. For later on, the hope would be that the astronauts are trained sufficiently to be able to accommodate those changes, and they can do the science investigation autonomously. They would know that they saw basalt or some kind of breccia in this one area, and they need to take an additional sample. They would know they need to go to these places because they have the geology training. And maybe they have an algorithm or something that is helping them decide, "If I need to go to these three places, what's the best route for me to go through?" So it's helping them with traversing.

Hargitai:

Do you have any favorite site where you would land if you would be an astronaut on the old mapped areas that you mapped?

Skinner:

Yeah, so my favorite map that we made was the Nepenthes Planum map, which is the area between the highlands and the lowlands in southern Utopia. Nepenthes Planum is an area that kind of sits in between that, we call it a boundary plain, so it's the high and lowland boundary plain. And on that, there are these pitted cones and flows, effectively. And we had interpreted that map and an associated paper as being potential mud volcanoes. Other people have interpreted them as being juvenile magmatic volcanoes, and we don't know the answer to that. If they are mud volcanoes, then they would be bringing up material from great depth, and I think that they would be a very interesting place to be able to look at to see if they are mud volcanoes. If they're mud volcanoes, then look at the stratigraphy of the material that's being brought up and try to put that into a subsurface architecture. If they are juvenile magmatic volcanoes, they're relatively young, and to see what kind of chemistry they would be. So that whole boundary plain in there, I think there would be some interesting things to see.

Hargitai:

What was the most difficult mapping project that you ever had, maybe so difficult you couldn't even finish?

Skinner:

Right. So one that we haven't published yet but we are working on is a 1 to 20,000 verso scale of one HiRISE image in an area north of Hellas Planitia that is an exhumed basin, it's called Hadriacus Palus is the name of the plain, and then Hadriacus Cavi is the exhumed depressions. And in that, we see columnar joints. And so, it was volcanic, but we don't know whether it is in-place lava flows or even ash deposits that have been cooled. So we know it's volcanic, and we also see channel cross-sections, and so we know that there was this kind of back and forth between vulcanism and some kind of climate-driven overland flow and kind of flood plain. And so, there are a lot of interesting things that go along with that. And we have not finished it yet because it's complicated to do cartographically, to show all this information at these very local scales. We haven't done this for Mars.

Chris Okubo did some kind of structural mapping, but we're trying to figure out how to do geologic mapping in these areas. And it's also just geologically complicated because we don't know–if it is a welded tuff, which can fracture into columns, that means that the vulcanism was of a different type than we observe later in Mars's history, so it's more caldera-forming eruptions, like Santorini, perhaps. And so, it's things like that. And we see these kind of uplifted massifs, and they might be crustal massifs from the basin, or they might be fractured pieces of an old caldera, so there's a lot of complicated things that go along with that. The great thing about mapping is that all we need to do is to describe it. We can interpret it however we want to, but if we describe it accurately, that's really where we need to be. And so, as long as we're mapping it and objectively describing it, we're covered. The interpretations can be–you can quibble with that, and people can come back later on, but the mapping should be objective. So we're still working on that one, hope to get that out here soon. But that's kind of maybe one of my favorite areas, but also really super complicated. It's just a completely different way of approaching geologic mapping.

Hargitai:

And the final question is, if you would need to convince congressmen to finance planetary geologic mapping, what would be your argument?

Skinner:

Yeah, that gets into things that we probably don't need to be answering. I think that we can make a case for the value of geologic mapping from both an applied and a fundamental basically science. To understand our processes here and where we fit into the grand scheme of things, we need to understand those processes. We need to understand the geology on multiple bodies, and we need to understand those processes on multiple scales on multiple bodies. So at a global scale and also a very local scale, like we see in that Hadriacus Cavi area. Probably more importantly to people that make these kinds of decisions is understanding the applied science aspects of it, so safety of crew members, safety of assets that we put on these bodies.

That will be driven by geologic mapping, and cartographic mapping, and everything that kind of goes into–geologic mapping is not just the geology, but it's also the hazards and the distributions of materials, and all those things can fit under geologic or geoscience mapping. And so, when we talk about safety of our investment, geologic mapping has something to do with ensuring that those investments are well made and that they're safe. We don't want to put some asset adjacent to an unstable rock surface that might be in danger of kind of slipping and causing damage to our asset. So there's that aspect of it. Which is why we have the National Geologic Mapping Program for Earth. So it's 1-to-24,000 scale maps across all of the United States. That's done for basic science. That's also done for applied science, and resource extraction, and understanding where to put a road, and all of that. And if you look at the Geologic Mapping Act of 1992, it says both of those things. We need to have these maps so that we understand fundamental basic geologic process as well as an ability to understand how we can use these most effectively for humankind.

Hargitai:

Do you think that if the future is in commercial space exploration or mineral resource extraction, then like in the oil industry, planetary geologic mapping will also go towards commercial companies?

Skinner:

I think that that's probably–yes. And I think that we might have to put regulations in place as we progress because it could be in a similar situation that we had with the oil boom. And now, all of a sudden, we have lots of extraction, and we're not necessarily paying attention to land stewardship and what is the impact to the environment. And so, I think that we might be in a similar situation. We need to recognize the importance of land stewardship for ourselves as well as for our kids' kids because it's not just about us. So I think that yes, commercial is going to be the way to go for us to get to these places, but there will need to be regulations in place so that they are understanding that it's not just about taking, it's about preserving and keeping the landscapes where they need to be.

Hargitai:

Thank you very much.

Skinner:

Yeah, no problem. [Laugh] Yeah, it's fun.

[End]