Houston, We Have a Podcast. Episode 48: Moon Rocks

Gary Jordan (Host): Houston, we have a podcast. Welcome to the official podcast of the NASA Johnson Space Center, episode 48, Moon Rocks. I’m Gary Jordan and I’ll be your host today. So, in this podcast, we bring in the experts, NASA scientists, engineers, astronauts, all to let you know the coolest information about what’s going on right here at NASA. So, today, we’re talking to the keeper of all moon rocks in the world, Ryan Zeigler. Well, technically, they’re all held here at the Johnson Space Center by NASA in the Lunar Curation Facility. But Ryan is the lunar sample curator here in Texas and he’s also a planetary scientist. We had a great discussion about moon rocks, like the reason why we brought them back from moon during the Apollo Program, more about the facilities that keep them, and also what we’re still learning from them. So, with no further delay, let’s go lightspeed and jump right ahead to our talk with Dr. Ryan Zeigler. Enjoy. [ Music ] Host: Ryan, thanks for taking the time to come on the podcast today. I can’t believe it, but we’re actually finally going to talk about moon rocks. Ryan Zeigler: I know, I mean you’d think this was a cursed subject or something. Host: Well, it’s interesting because — and correct me if I’m wrong — all of the moon rocks that were collected on the Apollo missions are here, correct? Ryan Zeigler: Most of our here, about — about 85% are here or maybe 80% are here, 5% are out with scientists, and about 15% are at a secret remote storage facility at White Sands, so — Host: Oh, okay. Ryan Zeigler: Not that secret, I guess, so. Host: The secret’s out now. Okay. So — but — but the moon rocks were collected on just human missions, right, not robotic missions? Ryan Zeigler: For NASA, yes. Host: Okay. Okay. So, were there other lunar acquisition — like robotic ones? Ryan Zeigler: Yeah, so the Soviets had three Luna missions — Luna 16, 20, and 24, and they collected about a pound of samples. Host: Oh, really? Ryan Zeigler: Yeah. Yeah. Host: Robotically? Ryan Zeigler: Robotically, yup. Host: Okay. Very cool. Must have been a different profile. But we went a couple times, right? We did — we did Apollo, you know, 11 through 17. Ryan Zeigler: Yeah. We had six missions that landed on the surface. Host: Exactly. All right, a lot of moon rocks. So. So, let’s talk about moon rocks, themselves, because, you know, how I imagine it is just, you know, gray rocks. But I’m sure — and I’m sure as — from a geologist’s perspective, there are interesting ones and there are — there are not so interesting ones. And there was — there was just some decision-making that went with the acquisition of them. Ryan Zeigler: No, absolutely. And you’re right, though. If you look at moon rocks, most of them are kind of boring to look at. I mean they have a bit of an image problem. Most of them are sort of gray rocks but there’s a few things about them that really set them apart. They’re really old. They formed on a body with no atmosphere, so there’s a lot of micrometeorite impacts into them. There’s a lot of things that set them apart from Apollo’s — from terrestrial samples. And so, they are really interesting to scientists for a lot of those reasons, yeah. Host: For sure, definitely. So, some of the first ones were collected from NASA on Apollo 11, right? Ryan Zeigler: Yes. Host: Awesome. So, how much — do you know how much they collected? Ryan Zeigler: It’s about 25 kilograms, so about — a little over 50 pounds. Host: All right. Ryan Zeigler: Yeah. Host: But I guess it felt different when they were actually collecting it. Ryan Zeigler: Well 1/6 as much. Yeah. I know. I mean everyone was super strong on the moon and it was great. You could jump super high, except for the spacesuits, I think. Host: Oh, yeah. Yeah. So, what did they used to collect it? Was it kind of bending over and picking it up or was it — Ryan Zeigler: Well, they couldn’t bend over very well and that was good for us because that kept them from touching them with their gloved hands because the gloves were a source of contamination. So, they had specially designed tools made out of either stainless steel or aluminum. And so, they — like, basically one of those long claw things you see that — like the t-rex with the two claw things, that’s kind of like that, only NASA, so it was made of steel. Host: Okay. Ryan Zeigler: And then they had sieves and they had some rakes. And so, they had a couple different instruments — tools to help them collect them. Host: Okay. And that was all planned ahead of time. They knew that the — did they understand the surface of the moon before they went? Ryan Zeigler: They understood it pretty well. What they didn’t — they underestimated how important the impacts were on the surface. And on Earth, impacts are a relatively minor thing because we’ve got an atmosphere. So, you see shooting stars at night and that’s little sand sized stuff being burned up. On the moon, all of that stuff, it’s the moon going several kilometers per second. So, it’s a much finer grained place and there’s just — yeah. So, the tools they use evolved over time. On Apollo 11, they had one set. And by Apollo 17, they had a much more evolved set. They learn from being there and sort of redesigned them on the fly, so to speak. Host: Okay. That makes sense. You go on the surface and you have people actually using the tools and then providing real-time feedback. Ryan Zeigler: Exactly. Host: Hey, this worked, this didn’t. I need this bigger, this smaller, this longer, whatever, so. Okay, that makes a lot of sense. So, when they collected them, what was that process like? Did they kind of put it into bags and seal them up or was it like a bin? Ryan Zeigler: On Apollo 11 especially, because they didn’t collect that many rocks, I mean 50 pounds sounds like a lot, but rocks are heavy. So, they had a special box with a metal-on-metal knife edge seal that allowed them to seal them away. And so, they would collect them with the tool, put it inside a Teflon bag, roll up the bag, and then the bag would go in the box. Host: Okay. Ryan Zeigler: And then at the end of Apollo 11, just before they were sealing them up to put them inside, Neil Armstrong looked at it and thought that the box looked kind of empty, so he got his shovel out and literally just shoveled a bunch of dirt into the box around all of the other samples. Host: Really? Ryan Zeigler: It’s — almost as an afterthought. And it ended up being like 11 kilograms or something. And it being almost a quarter of the sample they brought back. Host: Whoa. Ryan Zeigler: And it ended up being the largest single sample from Apollo 11 and probably one of the most important. And it was just — he just looked at it and thought, this is silly, I’m going to go all the way to the moon and I’m going to bring back a half-full box of rocks. So, he shoveled some dirt in, sealed it up, and that came back. On later mission, when they started collecting more rocks and would fit in the rock boxes, some of them came back just in the Teflon bags, sealed up tight, like cookies or coffee or something. But those probably saw a little bit of atmosphere. Host: Oh, okay. So, the idea was to protect it from the Earth’s atmosphere, once it got back, to avoid. Ryan Zeigler: Exactly. But the boxes are heavy and so they couldn’t bring 10 boxes to bring back all those samples. So, they decided that for some samples, just being sealed up and minor exposure to air would be okay. Host: Okay. So, why did the dirt ended up being one of the more important pieces of Apollo 11? Ryan Zeigler: Well, one of the things they didn’t realize — because the impacts are so important on the moon, and a lot of the material just gets spread around. And so, the dirt — the soil — the regolith, official — is the technical name for it — is a really good average composition of a large area on the moon, whereas the rocks mostly come from that local area. So, you collect the rocks, you learn a lot about the local area. You collect the soil, you learn about the local area, but also exotic stuff coming from farther away. And it being so big, and hey, us having so much of it, everyone wanted Apollo samples when they came back, and obviously, we had a very limited mass. And so, them bringing back more than they expected opened up new studies just based on mass availability. And we also used those as a goodwill sample. We — every country on Earth in 1970 got a piece of the moon as a gift that came from that soil — that big shoveled soil. They took out the bigger particles, put them in plastic, took some flags they had flown to the moon, put it on a plaque, and they just handed it out to everybody. It was great, yeah. Host: I wish I — Ryan Zeigler: All because — all because Neil thought to shovel in a [inaudible] we’re real close, so. I call him Neil, so. No, I mean all because he had the — you know, the foresight to do something like that. Host: Exactly. So, what was interesting about the Sea of Tranquility, whenever they were picking the location for Apollo 11? Ryan Zeigler: Honestly, I think it really came down to safety. I mean they had some really strict constraints. They — first time, they wanted something near the equator, so they used less Delta V, less fuel. They wanted something flat, so they’d have to worry about landing on, you know, a crater, which they almost did anyway, and they had to avoid it. So, a lot of it came down to it had to be on the equator and it had to be flat. And then they used spectroscopy. They looked at the light and it was bouncing off the surface and trying to find a place that was slightly unusual. And it turned out, Sea of Tranquility had a lot of titanium in it. And so, the light bouncing off it looked a little different and so they thought, let’s go try that place. And then when they went to 12, they had similar constraints, but they went to the other end of the spectrum. And they got low titanium basalts. And so, you know, science wasn’t driving the landing sights at that point, but they were still trying to maximize how much science they could get out of it. Host: Right and, you know, priority one was safety. Priority two was all right, in terms of the safest areas we could land, this one is also — Ryan Zeigler: Exactly, that’s how they did it. Yeah. Host: Okay. Cool. So, what’s — what was interesting about titanium then? Ryan Zeigler: On Earth — I mean this is sort of a technical detail that almost no one’s going to care about. But on Earth, you know, basalts only have a weight percent of titanium, 1% titanium. And on the moon, that’s 8 or 9% titanium, and it tells you about the interior of the moon and what was melting to form these basalts. And it’s quite different than Earth. And so, it was telling us about how the moon formed and evolved, all from one rock on the surface. And it wasn’t the whole story, but it sure got things moving in the right direction. Host: All right. Ryan Zeigler: Otherwise, we’ve been wasting our time for 45 years. Host: Well, then so that was just a piece of the story. And then you went to — we went to different areas to kind of let — you know, we have these Apollo missions, let’s use them to our fullest advantage. Let’s figure out this story of the moon. So, what were some of the decisions — and you said Apollo 12 was lower titanium — but what were some of the other decisions for the later missions? Ryan Zeigler: So, for the later missions — if you look up at the moon at night — and this is super basic, but there’s dark parts and light parts. And the first two missions went to the dark parts, those are mare basalts, like you would get in Hawaii. And then there was the bright parts, which actually make up about 80% of the moon, so they need — they were like, we need to go to one of these bright parts and see what make up the Highlands. And so, same constraints, Apollo 14 landed pretty close to Apollo 12, near the equator, but in the Highlands. And then they got those samples back and realized, wow, everything’s an impact, everything’s a breccia, a rock made of pieces of other rock. It’s like a jigsaw puzzle almost. And then after that, when they got to 15, 16, and 17, those were the J missions, so they had a Rover, they had much more — better suits, they had a lot of other stuff. And so, then they were able to go to more technically challenging sites that were, at the junction, between the bright parts and the dark parts mostly. And so, also, I mean I’m sure you know this and all of the pilot — all of the Apollo astronauts are pretty much test pilots. So, just landing on a flat bit, I don’t think he was doing it for them. And so, Apollo 15 and Apollo 17, when you hear the astronauts talk about what it was like to land there, like landing in this little narrow valley on Apollo 17, and Apollo 15 landing and coming over this huge mountain. And then having to get down really fast and land onto — before the big canyon. Host: Canyon. Ryan Zeigler: Yeah. You know, and so, you know, they were able to do more technically challenging things with flying too. Host: Okay. Yeah. Well, that was — that was their thing, right? Ryan Zeigler: Yeah. Host: But then on — was it Apollo 17, Jack Schmitt, now you finally have a geologist, right? Ryan Zeigler: Right. I mean, and Jack had played a really important part. I mean Jack comes to all of our science conferences. Jack has PhD in geology. He’s way smarter than I’ll ever be, and he still comes to all of the — all of the conferences and many, many, many a debate ends with, well, when I was on the moon — and that’s when you know you’ve lost the argument because he’s really [inaudible]. You know, you don’t get to use that. No, Jack was there. And so, he was able to help select the sites but when they were on the ground, he was — you know, everyone got a — basically a master’s degree in geology as part of their training. But he already had a PhD and was one of those people who trained the other astronauts in geology. And so, he really was able to spot and collect things from a different perspective. Host: Okay. And was — did he have a part in deciding where they were going to land and what things to pick up and bring back? Ryan Zeigler: I’m sure he did. And I mean he started to tell a story at a meeting a couple months ago, about well, that’s not how we selected that site. And he never finished the story, so I don’t have the whole story yet. But I don’t think the sites were selected that far ahead of time. As they were leading up to a new mission, the scientists and Jack, because he’s one of the scientists, would get together and talk about where they wanted to go from science priorities. And then the mission safety people would be like, yeah, we’re not landing in the middle of Tycho Crater, that’s crazy, and then there would be some back-and-forth. And — but yeah, no, Jack was definitely part of that discussion. Host: Okay cool. So, what were — what were some of the — besides titanium — what were some of the more interesting things that you found? Because there’s a finite number of samples we have from the moon, right? So, what are — were some of the most interesting things that we found from those samples? Ryan Zeigler: Well, they’re really old. I mean — and that’s — that sounds very basic. But essentially, every rock from the moon is older than every rock on Earth. It’s not perfectly true. There’s some overlap in the middle. There’s like four places on Earth where they’re that old. But it turns — so the moon is just an ancient body. The fact that everything was either a volcanic process of basalts, like what you’d see in Hawaii, or breccia, something from impact, that threw people off. There was no water on the moon and that’s not true anymore. But compared to terrestrial rocks, which every rock you pick up on Earth has a mineral with water in it and they couldn’t find any water in lunar samples until about 10 years ago. And it was only when instruments had evolved to the point where they could measure lower concentrations and new scientists came along and said, this doesn’t make sense. We need to re-examine these. And so, there was a little bit of missed from earlier. But the moon is a very dry place and that throws people off. Host: So, you said there’s– parts of it, you said it’s not true anymore. Ten years ago, we discovered there’s a little bit of water on the moon. What was the instrument that found that and where is it? Ryan Zeigler: It was something called the SIMS, the secondary ion mass spectroscopy. And so, what you do is you take the sample, you bombard the surface with ions, either positively or negatively charged, and then that sputters off what’s there. And before, we were using an electron probe, where you’re doing essentially the same thing, but with electrons. And they just — they started looking at a mineral called apatite and on every other planet where you find that mineral, there’s water in it. And then when they started looking at it on the moon, there was a fair amount of water in it. And so — and it was one of those cases where the analytical instruments in the ’70s were very good, and Apollo helped revolutionized them. But the little bit of water — the little bit that was missing, they just assumed was analytical error, and it was very hard to directly detect water because you’re not doing it by mass, you’re doing it by energy and so — anyway. So, they — so this — these new instruments — which weren’t new in the — in the 2000s. They were invented in the — in the ’80s. But by the 2000s, when new scientists came along, that’s when they started to figure it out. Host: Okay. Isn’t it also true that there are — on the polar ends of the moon, there are [inaudible] shaded areas that have I guess never seen the Sun, are their deposits of water there too? Ryan Zeigler: Almost certainly. We have limited direct evidence of that, but we have a lot of circumstantial evidence. There’s extra hydrogen there, so what’s the hydrogen there as? They — you get a different radar back scatter out of there and one of the only things that causes that is ice. And so, they did have the L Cross mission, which landed in one of these permanently shadowed regions, put up a plume of debris, and then it flew through it. And they did detect water, and so we do have some direct evidence, but — so that’s a different kind of water. So, I’m talking about water that came from the interior of the — of the — of the planet. And the water that’s at the poles probably is from comets and meteorites slamming into the surface over time. And the ice that’s in that, sort of migrating along the surface, and then freezing down in these cold areas. And so, I — you know, I’m talking about intrinsic water to the moon versus external water. The external water might be more interesting for like refueling spacecraft someday. Intrinsic water, it’s very minor and so it’s always going to be of geologic interest, but probably not economic importance. Host: I see. So, when you say that you were looking at rocks and using these instruments to find little — you know, use a different type of method to discover the water inside the rock, that was here on Earth, right? That was here — Ryan Zeigler: All of that was done on Earth. In fact, the — in Apollo missions — I mean you see the Mars missions now and they have Rovers and they do all these cool measurements on the — on Mars, they didn’t do that on Apollo. They had some surface experiments where they did some geophysical experiments on the surface, but that was on the moon, as a whole, and not on the rocks. The rocks were really not studied until they came back because anything they might have done on the surface could be done much better back on Earth. And since they knew they were bringing the rocks back anyway, they didn’t spend any mass, or time, or energy on that. They just collected the rocks and brought them back. Host: Plus, you risk the chance of contamination. Ryan Zeigler: Exactly. I mean we have a lot of talk now about, you know, what could be done on samples like on the way back and the answer is always like, don’t touch the samples, just bring them back. Just don’t touch the samples. We’ll do it when you get them back here. And we is not me, and we is not NASA. We, is this — the larger scientific community on the planet. And so, I keep using the royal we. And as my dad always asked, do you have a mouse in your pocket? No, it’s just, you know, it’s a very large and active science community that studies all these samples. Host: Well, and the — and one of the more important parts about that is there is a finite number of samples that you have, right? Ryan Zeigler: There is. There is. Host: So, whenever they’re bringing these samples back, the story from the Apollo days, what were some of the facilities that they were bringing them back to? What were some of the methods to make sure that they were acquired safely and properly? Ryan Zeigler: So, they had designed Building 37 here at Johnson Space Center was the Lunar Receiving Lab and they finished that in 1967, so a couple years before it came back. Because they had no real idea what lunar samples were like and because everyone has read War of the Worlds, they actually designed it as a quarantine facility. And so, both the astronauts and the samples went into quarantine for 21 days after Apollo’s 11, 12, and 14, to make sure all the bugs from the moon didn’t kill all life on Earth. And now once they got to the surface and they realized there was no water, and really no atmosphere, and they already knew that, they’re like, there’s no bugs in these samples. But through an abundance of caution, for the first three missions, they kept the quarantine going. And so, that was a facility designed to keep everything in, so everything leaked in. And the problem with that is everything leaks in on the samples, and we’re trying to keep the samples clean. And so, once they realized, no, this isn’t — you know, this isn’t a concern, we’re not trying to keep the bugs in. They redesigned laboratories in the building next door — in Building 31. And within about three or four years, they moved over and put most of the samples there in a positive pressure laboratory, where everything leaked out and everything leaked away from the samples. And the samples were stored in glove boxes surrounded by nitrogen and no one ever touched them, no one ever breathed on them, or coughed on them, like me. And so, yeah. So, that was — that was a pretty quick change they had to make. Host: Okay. So, some of the later Apollo missions — the samples collected from those I guess have some of the more pristine samples that you have here because of this method? Ryan Zeigler: Sort of. I mean there’s more of them and so some of them were able to be held in reserve. But all of them originally came back and were open and then — and initially analyzed in their lunar — in the LRL, in the Lunar Receiving Lab. And then it wasn’t till like ’73, ’74, when all of the samples got moved over to the next — to the next thing, so yeah. Host: So, then the actual study of — or the actual process of studying, what’s that like? What is — what do you do to actually figure out what’s inside? Ryan Zeigler: Wow. There’s so many different studies. So, I’ve been the Apollo curator for about six years now and I’ve had almost 400 individual requests to analyze sample. So, I’d like to go through them one by one — no? Okay. So, yeah. Yeah. No, it could be a long podcast. You know, if you — if you look at all of the collections in total, a lot of effort goes into dating the samples. And you would think, yeah, we already know the date of them. Well, as instruments and scientists get better — oh, man — the way they age date the samples has been refined over time. And there’s a couple different camps still trying to figure out exactly the age of the moon. A lot of study has been on the new water they found. But there’s even esoteric things. Like a guy in the UK wanted samples to do spectroscopy to figure out if he could see life on planet — on exoplanets. And so, all life on Earth has a chirality, it’s all left-handed or right-handed, and I’m not a biologist, so I don’t remember. But if you look at the light that reflects off an atmosphere with that light in it, can have a chirality to it. And so, they’re from orbit and Earth, they’re trying to do that. And one of the main sources of contamination for them is light bouncing off the moon. So, he needed to see what light bouncing off the moon looked like to put into his equations to understand whether they could see life on exoplanets from their atmospheres — from spectroscopy of their atmospheres. And so, every– I mean everything in between. It’s just crazy how diverse Apollo samples and samples, in general, can be used. Host: So, it’s fair to say you’re still studying them though, right? Ryan Zeigler: Oh, absolutely. This year, I — you know, we have — a new batch of requests just came in and we have 36 new requests for the — to be considered by the committee that reviews all of these and they’ll do that next month, so. I — they might find out about it on here. They don’t know how many we got, so they might be a little dismayed at how much work they have to do. Host: We’ll put this out a little bit later, so we don’t have any spoilers. Ryan Zeigler: No, that’s okay. They wouldn’t listen to me anyway. Host: Okay, so when you’re cracking them open — and some of the — some of the first times you were actually — you — now you have scientists that have their hands on these lunar samples — the first time. Ryan Zeigler: They better not. Host: Well, oh, okay. They have — they have protective gloving — gloves and — Ryan Zeigler: Yeah. Sorry, sorry, sorry. Host: Proper equipment to analyze the samples for the first time, first time humans have ever done that. What were some — was some of the first things that they wanted to look at and some of the first things that they found? Ryan Zeigler: So, some of the very first measurements that were done, after the Apollo 11 samples came back, were actually done here. So, the LRL was both the containment facility and the curation facility, but it also had a certain number of built-in instruments to do some of these initial preliminary examinations. And one of them was to look at the radiation in the sample. Now everyone hears radiation and thinks, Chernobyl or — no, what they’re trying to see is the natural radiation that every rock has. And so, they built a special pit underneath Building 37 that was lined with dunnite, a special type of rock from Earth, battleship armor from pre-nuclear tests. So, the — it could drive down the low levels of natural background radiation. Put the samples in front of a detector and then see just how much radiation was coming off of these. And so that was one of the very first things done. They had a gas lab to see what kind of gases came off it, whether there was a, you know, measuring the solar wind. So, it was — it was measurements like that that were initially done at Johnson Space Center. And then almost immediately after those initial measurements were done, they went out to I think 50 or 60 different groups around the country who were pre-approved, and they all had different stuff they were doing. Host: Unbelievable. So, I guess to work with this and to find out something specific, right, if you wanted to find out something more about radiation, there’s something special that you have to design, something special that you have to do. It’s not just chiseling at it and looking at it and say, ah, there’s the radiation. There’s like this huge — this very unique type of experiment and facility that you have to design. Ryan Zeigler: Right. And that particular facility was both expensive and time-consuming. And so, that was the kind of thing that NASA was going to take on, where — because they could use Apollo money on it. And then other things that didn’t require quite such specialized equipment, that could be done better by the experts in those individual fields at the different universities and other institutions. Host: There you go. Okay, so I’m assuming that one of the main objectives, when you have these samples of moon rocks, is to find out what happened to the moon. What was the formation of the moon? So, does some of your findings support Giant Impact Theory? Ryan Zeigler: I think, at this point, pretty much all of the findings support Giant Impact. Now there’s still — yeah. I mean there’s still a little bit of debate about how big the impactor was, or the exact timing, or — but as far as I know — and I go to all of these conferences, whether I like it or not, I’m — and, you know, keep an eye on these guys. And no, I mean everyone — no one’s arguing about — at these science conference — whether there was a Giant Impact. They’re arguing about the details of the Giant Impact. I know there are one or two holdouts, but that they are being increasingly marginalized, just by the — by the data that’s coming off the samples. Host: So, we can pretty much sit down and say, yeah, it was some kind of Giant Impact Theory that formed it. Ryan Zeigler: At this point, yes. I mean, although if you’d asked me 10 years ago if there was any water on the moon, I would have said absolutely not and everyone agrees on that. And so — but there’s physics involved here and I don’t understand physics because I’m a geologists. But I mean the angular momentum of the Earth-moon system and the spin and all that, that’s really hard to do any other way. And that’s not going to change, like we’re not going to learn how to measure angular momentum better. So, I don’t think the Giant Impact is going away, yeah. Ryan Zeigler: Okay. Okay. That’s fair. So, kind of going back to some of the facilities that you have. I’m imagining — I’m imagining these guys in gloves and you said, oh, no, they’re not going to be touching it. They’re going to be wearing proper equipment and they’re going to be using — you know, they’re going to make sure they’re not — nothing’s going to get contaminated. What does that look like? What is this — you say, bunny suit? Ryan Zeigler: Well, so in our lab, if you want to come and study the samples — so, yeah, you would put on a full bunny suit. Think white polyester suit head-to-toe. Host: Okay. Ryan Zeigler: Basically, a pair of coveralls, cloth gloves, a hat. Not — we don’t have to wear masks most of the time. And then over boots. And then you go into a laboratory that’s sterile — not sterile because they’re — that’s very clean. And then the samples are inside the cabinets. And then you put your hands through neoprene gloves and then if you needed to handle the samples, themselves, on the inside of the neoprene gloves — excuse me — you would put Teflon gloves. And so, you can only touch the samples with Teflon, or aluminum, or steel. So, you would have to actually handle the samples in our laboratory through three layers of gloves, inside of a controlled atmosphere cabinet. Yeah. And so, now not everyone in their own lab has to do that because we have to keep the samples ready for anyone to do anything, as near as we can. If somebody knows that they’re not going to contaminate the samples by handling them in air, what — when I did this at Washington University in Saint Louis, before I came here, we had a clean flow bench. We would take the samples to JSC [inaudible]. We would open them, we would pour them out, then you rinse them off with acetone, you get some of the dust off. Picked them up with tweezers, never touched them with my hands, despite what the pictures show. And then we would get them ready and when we send them off to the reactor to do — to do — to do measurements and stuff like that. So, clean space, controlled atmosphere, but not a controlled atmosphere — sorry. Not inside of a nitrogen glovebox. And that’s — most people don’t have the glove boxes we have. They cost a quarter of a million dollars each and there’s all this infrastructure that goes into it, so. Host: Wow. Ryan Zeigler: Yeah. No. Host: Take your moon rocks very seriously. Ryan Zeigler: Yeah, well we spent 24 billion dollars to bring them back, we ought to — we ought to keep — you know, okay, we’re trying to keep them safe for long term. Host: Exactly. And like you said, you’re still studying them and there’s still a lot of things to be discovered. So, the last thing you need is to — is to waste any of the samples. Ryan Zeigler: You don’t get to have two bad days in curation. You have one bad — you can’t un-contaminate a sample. If something goes wrong and water got on the samples, it’s always going to have had water on it and it will eliminate certain number of measurements. And so, no, we — yeah, you’re right. We do — we have procedures — I mean I used to make fun of procedures before I came to NASA. Now I really make fun of procedures, but I understand why they’re important and why we have them. And so — and we have like 160 of them to run the lab and all the different things we have to do to them. Yeah. Host: Wow. Ryan Zeigler: Yeah. Auditors love us because we’ve got everything written down. It’s great. Yeah. Host: Okay. So, then that brings me to the thought that there’s a finite number of — or finite amount of moon rocks that you have. So, how do you keep track of it? How do you make sure that you have — that you’re taking advantage of this finite amount? Ryan Zeigler: With great effort. So, every sample that we loan to a scientist to do study on — to do a study on, we keep track of. And everything’s a loan and they have to return it. So, if they destroy it, as part of the analysis, then great, then they have better have had permission to do that. Then that’s great, we mark that off. But anything else, they would study, and they would come back. And so, once a year, I send them all an inventory, and they have to check off and they say, yes, I have all these samples or no I don’t, in which case bad things happen. And no one ever says, no, I don’t. They’re very, very conscientious. And so, 125 inventories a year gets sent out and I have to — you know, we all – we all take care of it. Now we do in — an internal inventory with JSC security where once a year — or once every other year, they come by and they ask us to find every sample for them. And so — yeah, no. And so, we have to meet the same bar as everyone else, just every other year, because we have 100,000 samples and most scientists have 50 or 100, so. Host: So, the interesting thing about the moon rocks is that you’re still — you’ve collected them so long ago but you’re still finding stuff out, right? And so — so what are the — some of the more recent findings that you’ve been having? Ryan Zeigler: Well, one of the more recent findings that has come out and in the last five or six years was that perhaps the Solar System didn’t form the way we originally thought it did. People noticed that there was a preponderance of samples on the moon that are 3.9 billion years old. Now the age, itself, doesn’t matter to you or me. But within the Solar — and they were all formed by giant impacts. Now 600 million years after the Solar System formed, there shouldn’t be a bunch of giant impacts. Everything should have quieted down by that. So, for — to explain the lunar samples, they had to come up with a new dynamical model for the evolution of the entire Solar System. So, originally, it was — the new one was called the Nice Model because it was formed by a bunch of scientists in Nice, France, which I hope is true or I’m going to get phone calls. And that said that Jupiter, and Saturn, and Uranus, and Neptune all formed in much closer to the Sun. They gravitationally interacted and then they spread out 3.9 million years ago. And when they did that, they took all of the asteroids and comments and spun them around the Solar System and that caused the Giant Impacts. Now people don’t like the Nice Model anymore. Now they have something called the Grand Tack Model, but it doesn’t matter. Any of the models for planetary formation actually have to explain the ages that we see in the Apollo samples. Now the ages, themselves, are actually old. They figured that out early on. But no one noticed how many ages were 3.9 and put two and two together with what it meant for the Solar System, as a whole, until more recently. And so — you know. So, when people ask me what moon rocks can tell you about, I say, well, where Jupiter formed. And they always look at me like I’m lying. Host: Well, it’s kind of amazing how we can find so much about our Solar System, just from studying so close to home. I’ve had a couple conversations with some — some of the meteorite sample curators and like — [ Inaudible ] Host: Yeah, I’ve had conversations with all of them and just the stories that you can find from analyzing these rocks are fantastic. Ryan Zeigler: And it’s really nice because the meteorites are all really old. So, almost all the meteorites are older than all the Apollo samples. And all the Apollo samples are older than the Earth. And so, each of them gives you a different window into how the Solar System formed. And if we only had one, we wouldn’t know the whole story, or even if we only had two. Having all three is really important to understanding how things work. Host: So, looking towards the future, are there missions that you are kind of planning for for possibly extra curation missions or anything that is going back to the moon to analyze something new? Ryan Zeigler: Well, I mean there was just a big announcement yesterday, obviously, that, you know, NASA is refocusing on the moon and I think want to send people back to the moon. And there was some talk about robotic missions, both to do in situ science, science on the surface, but also to hopefully bring back some samples. I stayed at Wash U to be part of the Moonrise Team, which was a new frontiers mission, so a billion dollar mission, to bring back samples back from the far side. We came in second twice to Juneau and OSIRIS-REx, I’m not bitter, especially while I was at the Juneau — at the — at the OSIRIS-REx launch. No. And then this most recent time, they just down selected Caesar and Dragonfly as the finalists for the next round of New Frontiers, so Moonrise won’t go either. But within those two, Caesar is a sample return mission. It is a sample return mission from the surface of a comet. So, there was a Rosetta Mission by Europe and it went and it — you know, it went into orbit around a comet. And then sent a lander and then studied that and I don’t know that much about it. And I don’t know that much about Caesar yet because it’s brand new. But their plan is to bring back samples from the surface, both gas and ice, and I think rock samples, back from the surface of a comet, to Johnson Space Center, where we will curate them. So, we’re going to have to figure out how to curate gas and ice. Host: Oh, yeah. Ryan Zeigler: And it’s not that we don’t have an idea. We do but we have never had to do it before. And so, we’re going to spend the next — luckily, we have about 15 years to build up the capabilities to get ready for that. Host: Okay, so capabilities in terms of facilities. Ryan Zeigler: Right. So, I mean keeping ice cold is easy. There’s lots of ice labs around the country. But if you want to treat that ice like we treat rocks, where you’re going to subdivide it, and that’s different. If you want to work on it cold, that’s harder. And also, there’s cold and then there’s cold. So, minus 20, great, that’s easy. We can do that with a freezer. Minus 80, oh, that takes robotics and [inaudible] minus 160, like do you really want to keep it like the temperatures on the comet, itself? And these are things we still don’t know all the answers to and we don’t even know the requirements yet. But this is going to be what we spend the next decade figuring out. Host: Okay. All right. Well, best of luck to you. Ryan Zeigler: Yeah. Yeah. Host: It’s going to be a long process. Ryan, thank you so much for coming on. That was — that was fantastic to learn about everything — all these moon rocks. I’ve been dying to have this conversation. Ryan Zeigler: It was my pleasure. Host: Fantastic. And it’s crazy what the moon rocks can tell you, just from looking at these and that we’re still finding stuff out and just, you know, the story of water that has to — you have to rethink these thoughts that — and findings from decades ago because there’s something new that we found. So, it’ll be interesting to see what comes up in the future. Ryan Zeigler: Yeah. Absolutely. Host: All right. Very cool. Thanks for coming on. Ryan Zeigler: All right. My pleasure. [ Music ] Host: Hey, thanks for sticking around. So, today, we talked with Ryan Ziegler about moon rocks and the facilities that are keeping them. And honestly, we’re still hurting so much from these rocks. If you want to know more about the rocks, you can go to the ARES site, that’s our Astromaterials group. It’s ares.jsc.nasa.gov. You can go to that site also to find out how to get your hands on a meteorite sample if you actually want to study meteorites or moon rocks. On social media, you can follow the NASA Johnson Space Center accounts or the Astromaterials accounts, they have their own on Facebook, Twitter, and Instagram. You can go to any one of those accounts and use the hashtag ask NASA to submit an idea or question for the show or for I guess any other reason. But if you want it to be brought right here on Houston, we have a podcast, just make sure to mention the show, and then we’ll actually bring it on, maybe answer it, or dedicate an entire episode to it. We have done in the past. This podcast episode was recorded on February 14, 2018. Thanks to Alex Perryman, and Tracy Calhoun, and Jenny Knotts. Thanks again to Dr. Ryan Zeigler for coming on the show. We’ll be back next week.

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