NOVA; To the Moon; Interview with Dr. David "Dave" J. Roddy, Astrogeologist at the US Geological Survey, part 2 of 2

One of the principal avenues that we followed to try to prepare the astronauts for the lunar surface was to create a crater field. And the simplest place to create a crater field was in volcanic centers, which is what we expected to find on the moon, which, indeed, they did to greater and lesser degrees. The effort that we went to was rather large because we took a great deal of TNT dynamite explosives out to the Centurlake Crater Field, just east of Flagstaff on government land for the surface land. And we set the charges in such a manner that we would have craters that were essentially the same distribution, the same number of craters, if you will, with the same depths and diameters as we expected for the Apollo 11 and 12 landing sites. So we actually made a crater field of many acres and size that had several hundred craters in them that looked for all intents and purposes if you took an aerial photograph, it looked

like a surface of the moon. And indeed it did look like where they were going to land. Then we took the astronauts, repeatedly out to these sites, and did everything from sort of a show and tell to give them an overview to actual exercises as though they landed on the lunar surface. And we're doing EVA or extra vehicular activity traverses to collect information. So it was as close as simulation as we possibly could. They even got to the point where we suited the guy, where the guy suited up, and there was live transmission back to NASA, Houston and JSC, where they could evaluate the performance as though they were on an actual mission. We also had a crater field that we developed from some 40 acres down in Cottonwood, which is about dead center of Arizona. And we had a field there that we created 400 craters by explosives. And that was to simulate the Apollo 15 landing site.

And there we had full up EVA extra vehicular activity traverses where the prime crew and the backup crew in two separate elements went from point A to point B in a complex pattern to collect information. And then we evaluated that after they were finished, and it was very much given take exchange between the astronauts who wanted to understand how to collect information better, and our cells who were trying to help them. Now, how did it stop for just a minute? Well, on a contrary, it wasn't Rube Goldberg in the normal sense of the word, or in any sense the word as far as we concerned, because we actually knew enough about cratering processes and creating mechanics by that time to know how to set charges at various depths and get craters that had diameters that we expected and depths that we expected. The real bottom line all this is that if you're going to take your pickup truck and you're going to drive from here up to the top of the San Francisco peaks, which is 12,000 feet

high, you better have a good plan or you're going to be in deep trouble pretty quickly. So what we wanted to do was have the guys have the astronauts sufficiently well prepared that when they got to the lunar surface, that they knew exactly what they wanted to do because they had in effect been there before. And so we put together a plan that was based upon the highest quality resolution photography of the lunar surface in the areas that they said they were going to use as landing sites or potential landing sites. We took those photos and we made the measurements of the craters. We got some idea of the depths of the craters and we simply went to the drawing board, did the calculations were necessary. That told us what size charges delay out and we looked at the distribution of the lunar craters and we simply put the charges where they would simulate that part of the lunar surface straight forward.

After you thought about it quite a bit, it was straight forward. You tell me about taking your plane out and doing some of this stuff I thought. That was indeed true. On the first go around when we made the craters over east of Flagstaff, we basically knew what we wanted to do and it was the first simple and straight forward attempt and that's how it turned out. Straight forward and it was simple and the astronauts made considerable use of it as we gave them the various elements of training on cratering mechanics and creating processes and cratering shapes, morphologies if you will. When we went down to the cottonwood Arizona area, we were somewhat more sophisticated by then in the sense that we had done it before, in fact we had made two fields up here and made major use of them. I might add that we even went so far as to put the simulated rover that was constructed by our engineers here in our branch at the US Geological Survey. We took the rover out and the astronauts got in the rover and they drove the rover on various

exercises, training exercises, so it was a major use effort. It was big time because it was exactly where it was designed to look exactly like what the guys were going to see when it got to the lunar surface. Now you also took them to some lunar simulations, right, nuclear, right? Nuclear. Well, before I lose that other one, let me comment, you would ask about other techniques of them, of acquiring data. We did have the situation in cottonwood Arizona orchestrated such that when we made that crater field, we detonated it so we didn't get the public running all over the place and wondering what was going on. We detonated the charges in segments or in groups and at one time we detonated about 180 all at once and then the rest of the 400 were detonated in groups of smaller groups like 65 or so.

But doing that, we did fly an aircraft down of which I and one of our chief pilots participated in getting high speed photography of it so we could actually show the astronauts later on what an impact crater, the formation of an impact crater looks like dynamically. And that really took us a long, long way in terms of the training because you can go out and look at a tire laying on the ground, you can figure out, well, that's a tire laying on the ground and I sort of know how it got there and how it was formed. But when you go look at a crater, it's complex enough that you need to have some feeling for just how the mechanics of formation operate and that high speed photography that we took was a real help in astronaut training. Now the nuclear sites, you took them to nuclear sites, why? We did go to a number of other sites, we did go to a number of other sites that we thought would help the astronaut community understand that both the dynamics as of cratering as well as the surface features that are formed by large crater.

For example, we were in a, the U.S. was in a joint operation with a number of other countries including Canada on uses of large explosives to, large explosive charges, I should say, to create craters as well as do other kinds of studies. And there was one event in the late 60s that was one creating event in the late 60s in which the U.S. and Canada were participating together. And it seemed to me since I had been working on some of those events in the past that the astronaut community could benefit significantly from looking at a very large single cratering event and then going down and walking across it. And so we actually had over a dozen of the astronauts, in fact the full astronaut community, the Apollo astronaut community did attend this experiment and they were welcomed by both

the U.S. and Canadian defense communities to participate jointly in terms of trying to let the astronauts see what these things look like when you have a large single event occur, either an explosion or an impact event are almost identical in that they produce same kinds of shockwaves. So when this event was detonated it produced a large flat-floor crater with sort of a multi-ringed like structures on a crater floor which is exactly like the giant mario-antile crater on the moon. So once again we were looking at analogues that were as close to what we saw on the earth as humanly possible. You're talking to Brent about Copernicus Ray and what a big deal that was. Give me, tell me that again. How do you impact related to Copernicus Ray? You're just just earlier today we were talking about that in your office. Ready? What if I take three?

Well that question involves thinking about a lot of things. First of all the astronauts were chosen, the specific individual they were chosen was the exception of Jack Schmidt who was the only geologist that was included in the Apollo crew that did go to the moon. The astronauts were chosen on the basis of their capabilities to fly machinery and I think that was frankly a wise decision. In fact having come from the Air Force myself I really applauded the conclusions that the NASA community reached and said we want this to be not only successful but we want it to be very successful. We don't want mistakes. We want it done right. And my impression of having worked with the crews, especially crews 13 through 17 was that these people were 11 and 12 too but Jean worked with those people.

These gentlemen were extraordinarily capable. Here this expression right stuff used a lot over and over again and it becomes somewhat trite. It isn't trite. There are people that can do things very well and if they're trained to do specific things they will get them done and the Apollo astronaut crews got them done. I can't fault any of the people that I worked with. In fact quite the opposite. This was the most interesting and the most exciting group of people and dedicated group of people I've ever worked with in my life. Who stands out in your mind? Frankly they all stand out. They were such a capable group of people and such a likable group of people that I found it just a enormous pleasure to work with these gentlemen. I remember different people for different reasons but I think Dave Scott was one person who typified the Apollo astronaut community as well as the military flying community.

He was a person who was openly dedicated to learning. In fact Scott is commander of Apollo 15. Commonly would come along during a field exercise and ask you to move things faster. Ask you to teach them more, ask you to show them how to do various kinds of things in more detail. There was never ever a question with motivation with the Apollo astronaut crews. I found that you had to run hard to keep up with them and that I found enormously pleasurable. Though it was not only fun but you knew what you were doing was going to have meaning to these people and that was part of a national program and it was just enormously exciting. You can only go to the moon for the first time once and we really wanted to see if it couldn't

be done right and those guys did it right and NASA did it right. Now you know Gene was obviously you know Gene was not happy with the way that NASA conducted the geology on the moon. Did you agree with Gene about that? Well that was a little early for me I was still coming out of the Air Force and going to graduate school and I didn't have a chance to really have a develop a mature view at that particular period of time. As time has gone by I have mixed emotions. Gene was a dedicated scientist. I think the most interesting and the most imaginative and the most far reaching person that I have ever worked with in the sciences. By the same token that was the first time to go to the moon and the engineering was enormously complex and they didn't want any mistakes as we said before.

We wanted to get the guys off the earth to the moon, down to the moon, back off the moon and back to the earth. That's really complicated. And to do good science at the same time it was a trade off. And so I think Gene's heart and mind were in the right place but I think NASA was doing the right thing too and it was a complex interaction. But take a look, if you want a real answer to this, it's happened now far enough back in time that history has been made and look at the wealth of information that we've gotten. Look at the enormous amount of changes and ideas about the origin of the moon. We never had lunar samples before, the outside of what may have been knocked off the moon by impacts and come into an earth gravitational orbit such that it landed on here. But we never collected material before and of enormous importance, we never had ages.

We never had ages of the lunar surface rocks that we could absolutely, unequivocal, you say, these came from the moon, no question these came from the moon. When Apollo astronauts brought back material and you analyzed it, you not only could tell what was in it, the materials that they brought back, that is what kind of minerals, what kind of chemistry. When we got the materials back, we knew for sure because you had it in your hand. Number two is when they did the radioactive age dating, there was just absolutely no question that we had ages for those materials on the lunar surface. That was like coming out of the dark ages, I mean the way, way back dark ages to a level of enlightenment that was just enormously important. We not only were able to collect the materials due to adequate, safe, competent, sane engineering by NASA, but by the leadership of shoemaker and others, we actually did good science.

It was an incredibly successful program and incredibly successful. Okay, terrific, do you want to do it? Why, why meteor crater? Why was it so important? meteor crater is the largest best preserved impact crater on the face of the earth. That alone makes it an important site to work on. But number two is it's in a unique position here in northern Arizona. It's close to Flagstaff, which is a beautiful staging area, so to speak, to get out to the crater and back. It logistically was easy to get to and it is the classic type of impact crater that we find exists on all of the planets and all the satellites in the solar system. It's basically a bowl-shaped crater with uplifted rims and an ejected blanket around it. That's exactly what you see on all of the other planets and all the other satellites in

terms of density of craters, the bowl shapers are the simplest and the least complicated and they are the most abundant. As you get larger, you get from bowl-shaped to flat floor, all the way up to flat floor with central peaks, all the way up to giant basins at a thousand miles across. But meteor crater is the classic bowl-shaped crater that is so common throughout the solar system. What happens when you have a meteorite, an asteroid or a comet, hit a hard surface and if it doesn't make one of these other more complex kinds of craters, it will make the simple type of crater right off the bat. So meteor crater is important for that reason alone. As you asked, not stood in meteor crater, but they tell a lot about the geology just by looking at the rim and the sides. How can I put this? By the time they got done with us and we got done with them, they were darned. And good.

The astronaut community actually had a capability for learning and that exceeds most other environments that you can imagine. They also wanted to learn. And so when you told them something about meteor crater, how does the rim get uplifted and can you see stratigraphy in it and what does it mean? They wouldn't stop there. They would ask you more and more and more questions until they fully understood what understood the rim in this particular case or the crater floor or the crater walls or the ejected blanket. They would ask you questions to the point that they felt that they were comfortable in understanding. It was an incredibly nice community, great community to work with. Got it. Cut. Terrific David.