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13 Minutes
Artemis II: 12. Please return to your seats
00:40:10
The Artemis II mission hurtles towards re-entry and splashdown.
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- [00:00]
Tim Peake
This BBC podcast is supported by ads outside the uk.
- [00:06]
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- [01:10]
Kristen Fisher
Save on tropical flavors at Whole Foods Market during the Savor the Tropics event with yellow sales signs highlighting seasonal finds throughout the store. The produce section is bursting with pineapples, mangoes and kiwis at their juicies.
- [01:25]
Dr. Philip Metzger
Grill up fresh seafood paired with tropical fruit marinades. Or grab and enjoy the spicy Hawaiian
- [01:30]
Kristen Fisher
pizza, huli huli chicken and more. Finish with a sweet slice of mango yuzu Chantilly cake.
- [01:36]
Dr. Philip Metzger
Savor the tropics and save at Whole Foods Market.
- [01:44]
Tim Peake
Welcome to 13 Minutes presents Artemis 2 from the BBC World Service. I'm astronaut Tim Peake and this is episode 12, approaching flight A10.
- [01:55]
Maggie Adairin
And I'm space scientist Maggie Adairin. We're following the progress of the first crewed mission around the moon in more than 50 years with a new episode every day.
- [02:11]
Kristen Fisher
Integrity Crew, when you are able, could you give us an indicator or an indication if you are bumping up against or touching the smoke detector in any way when you're over in that area of the cabin?
- [02:24]
Dr. Philip Metzger
We had a towel over there, but we don't think we're bumping into it. Give us a couple more seconds because we need to grab a few more pictures and then we'll try to get away from it for a minute
- [02:37]
Kristen Fisher
and we don't have any concern. You guys can stay over there. Keep taking your photos. We're just curious. Continue.
- [02:43]
Dr. Philip Metzger
All right, sounds good. Jenny? Yeah. We caught a view of Earth in window one and now we're completely distracted for a little bit. You guys are looking for it.
- [02:54]
Kristen Fisher
Thanks. Yeah, we love that.
- [02:55]
Tim Peake
We were just noticing.
- [02:57]
Kristen Fisher
It's really cool actually, in the data, that ecom scene, they're seeing an indication on the smoke detector and they think it's when the flash goes off.
- [03:06]
Tim Peake
So we're just curious.
- [03:07]
Kristen Fisher
Thank you.
- [03:08]
Tim Peake
And they're still learning things about the spacecraft as ever. We are joined by space journalist Kristen Fisher. Hi, Kristen.
- [03:15]
Kristen Fisher
Hi, Tim. Hi, Maggie. Gosh, you know, when the crew says they're distracted by a new view of Earth or whatever they're seeing, I'm immediately like, when can we get that photo? Because we've seen what incredible pictures they've taken so far. And really as we kind of check in with where the crew is at at this moment in time, that's really what they're doing right now. On their way home. They're continuing to take photographs of probably Earth more than the moon, which we've gotten so used to over the last few days. But really what the crew is focused on right now and everybody on the ground and everybody that's been following along in this journey quite frankly, is re entry. Probably one of the most dangerous and nerve wracking few minutes of this mission. And so to get ready for that, they really have to reconfigure the insides of the Orion spacecraft. They've stowed away their secret seats and their seat belts essentially to provide themselves some more space to move and float around and do all these scientific observations that they've been doing and taking pictures. So these last few hours before re entering the Earth's atmosphere are really spent configuring the Orion spacecraft for the proper configuration for reentry and getting themselves all suited up and ready too.
- [04:30]
Tim Peake
Yeah, and you mentioned about those photographs, Kristin. Earth will be getting pretty big in the window quite rapidly because yesterday we were speaking they were still closer to the moon yesterday day than Earth. Now they are very much closer to Earth. And of course as they get closer, Earth's gravitational pull gets even stronger. So they're at about 5,000 miles per hour at the moment and in about well less than 12 hours time they're going to be doing 25,000 miles per hour coming into the atmosphere. So they've got to start getting this spacecraft ready pretty quickly for that re entry process.
- [05:01]
Maggie Adairin
They did another return trajectory correction burn which lasted only nine seconds, but it produced an acceleration in velocity of 5.3ft per second second. So as you say, they're going at a fair clip.
- [05:14]
Tim Peake
Absolutely, Maggie. That burn's really important. But they still have one more critical burn to do that's RTC3. Return trajectory correction burn three. So that will be later on this evening, about five hours prior to RE entry. And that's one that will set them up on this trajectory to make sure the angle is perfect and the location is perfect.
- [05:37]
Kristen Fisher
And we just want to really prepare our listeners that, you know, there is going to be another loss of communications with the crew. Just like we saw when the crew went around the far side of the moon. It will not be 40 minutes, it will be much shorter. But we just want to prepare everybody that that is expected again and it is totally normal. But there is going to be a period of time where I don't care how well trained you are or how well prepared you are or how confident you are, RE entry is always a bit of a scary thing. And it just so happens that this RE entry is about 13 minutes long. What do you know, Maggie and Tim? Which harkens back to, I guess, really the whole reason the show was called thirteen Minutes to begin with. Right?
- [06:24]
Dr. Philip Metzger
Yeah.
- [06:24]
Maggie Adairin
So the first series was talking about the Apollo 11 astronauts landing on the moon. And it just so happens that they had 13 minutes of terror as they approached the moon's surface. That we had a designated landing site, but that landing site looked to be too rocky, so they had to extend their descent. So this 30 minutes covers that extension of the descent. And when they landed they were virtually on vapors, but they landed successfully. But yeah, there was 13 minutes of terror, which is what this whole series of shows is named after.
- [06:56]
Tim Peake
Yeah, that I remember listening to. That was Kevin Fong. And a brilliant, brilliant start to the whole BBC 13 minutes series and some wonderful warm interviews with the Apollo astronauts in there as well. As far as our astronauts are concerned then really, Chris, all they're doing is they're packing up their camper van, just getting ready to come home effectively.
- [07:17]
Kristen Fisher
Yeah, Tim. And so this is really the final test for the Artemis 2 mission. Everything else has been, I don't want to say perfect, but it's been pretty close. I mean you can't ask for much more than what this crew and mission control has given us in this first crewed test flight. So now the final big test, re entry and this heat shield and it's such a big moment. We thought it would be helpful to kind of walk through the re entry timeline and answer a few of yalls questions which have been coming in.
- [07:48]
Maggie Adairin
So the timeline for descent really starts at 7:33pm Eastern. This is when Orion separates from its service module. And this is the official Start of re entry.
- [08:00]
Tim Peake
Absolutely, Maggie. That service module has done such an outstanding job. It's provided not just the power and the propulsion for the entire journey, but as we've spoken about, the water, the life support systems, all of the things that's needed to keep that crew alive throughout the entire journey. But its job's going to be done. And once it's released, once it's separated, it's designed to burn up in the atmosphere. So European service module doesn't come home. So from here on, Integrity and the crew Orion module is on its own.
- [08:29]
Kristen Fisher
You know, it's a quiet moment, but it's a really powerful one. I mean, everything that supported the astronauts in space is now gone. And now it really is just them, the capsule Integrity, as you say, Tim, and Earth.
- [08:42]
Tim Peake
It's funny actually, Chris, you say a quiet moment there. I think it probably is a quiet moment for Orion. It's four bolts that hold that European service module to Orion. But on the Soyuz spacecraft it was anything but quiet. And I remember Jeff Williams telling me the night before coming home, he said, listen, when that separates, you're going to think it's all over. It's 14 pyrotechnic bolts going off next to your ear. It's like a machine gun. And the spacecraft, the Sawyer spacecraft literally blows itself into three parts. We lose the habitation module above us, we lose the service module beneath us. And it's a very, very loud and quite disconcerting moment. So hopefully for Orion it'll be, it will be that quiet moment that they'll be hoping for.
- [09:25]
Kristen Fisher
Man, at least you got the heads up.
- [09:27]
Maggie Adairin
Yeah, yeah, you were warned about it. Because if you suddenly hear that, you think, wow. Just moments later, at around 7:37pm, Orion performs its final raise burn.
- [09:40]
Tim Peake
Yes, and this is just a very simple burn that simply takes the Orion spacecraft away from that European service module and gets Orion safely away so it can start its re entry process.
- [09:53]
Maggie Adairin
I suppose you want separation between them. So this burn provides that.
- [09:57]
Tim Peake
Absolutely, yes. Yeah, it's a fairly minor burn compared to for example, the final RTC3 burn. That really sets Orion up for its reentry angle.
- [10:07]
Kristen Fisher
And so at this point, that's it. There's no going back. The crew is fully committed to the ride down.
- [10:13]
Maggie Adairin
At just before 7:53pm, Orion reaches entry interface about 400,000ft above the Earth.
- [10:23]
Tim Peake
Yes, so this is the point where really the spacecraft, it's regained all of that kinetic energy. It's been falling back towards Earth. It's now back up to about 25,000 miles per hour. It will be orientated heat shield first. And the air in front of it, the upper part of the atmosphere, begins to compress very rapidly in a shock wave. So it's a really aggressive dynamic moment there. And the spacecraft will start to absorb of that energy using the air as a massive air brake. It's got to slow down from 25,000 miles an hour to about 325 miles per hour. So it's a really important process there. And this process of slowing down actually causes ionization of the air because the impact is stripping these molecules of air, stripping electrons from them. And so that ionization causes like an electromagnetic shield really around the whole spacecraft. And that makes it impossible for a radio communication to carry out with a spacecraft. So for about six minutes we're going to have a communications dropout.
- [11:26]
Kristen Fisher
And for the astronauts inside, aside from launch, this is probably the wildest part of the ride for the crew inside. Astronauts have described this moment as riding inside of a giant fireball. The spacecraft shakes, the noise builds and then just silence.
- [11:46]
Tim Peake
Yeah. In the Soyuz, it certainly was an amazing experience. And obviously you also, you're feeling this firm push in your back. You've been experiencing facing zero gravity for a long period of time for this crew for 10 days. But that G force starts to build and it builds like a gentle push in the back of that gets higher and higher and higher. They're going to get up to about 4G during this descent through the atmosphere outside, it's going to get really, really hot. It's going to be up to 2,760 Celsius and they're going to see plasma coming past the windows. They'll see bits of the ablating heat shield. In the Soyuz, actually, it gets so hot our windows burn over and we can no longer see outside. And it gets really hot in the Soyuz. I think that their temperature control inside Orion is going to be a bit more comfortable than ours. Well, we were dripping with sweat inside during that re entry process. But it is a very dynamic phase of the mission.
- [12:44]
Kristen Fisher
You always hear the word dynamic from astronauts to describe this moment in the mission. But I mean, can you put this into plain English? What are you thinking, feeling when you are, when you're watching red hot plasma, you know, rush by you. What, what are, what are you feeling in that moment? I'm, I'm sweating just thinking about it.
- [13:05]
Tim Peake
Well, you're, you're concentrating back on your breathing technique because the G force is, is built up and so four people are essentially sitting on top of your chest. So you're focusing on, on breathing. You're looking at the spacecraft, making sure everything's performing well. And the spacecraft is actually rolling through the atmosphere. It's not just on a straight trajectory, it's rolling to the right, then rolling to the left. And these five roll reversals that it's going to do that changes the lift because believe it or not, it's not just falling like a brick, it's actually generating a small amount of lift over that capsule. And by rolling, you can adjust the lift vector so you can steer it left and right a bit and you can adjust your rate of descent.
- [13:48]
Maggie Adairin
Who's controlling those rolls?
- [13:50]
Tim Peake
Those roll manoeuvres will be automatically programmed in, but the crew can take manual control. And this is something that we had in the Soyuz spacecraft as well. If we needed to, we could take manual control of the spacecraft and adjust this trajectory. And that's what allows Orion to extend its range if it needed, for example, to land in a slightly different area because of bad weather conditions. The crew have that capability to extend the range of Orion by using these roll mano. So it's not just what we would call a ballistic re entry is where there's no control whatsoever. Ballistic is just coming back, not generating lift, falling like a brick. And that means you get up to perhaps about seven GS. It's much more uncomfortable, much higher temperatures. But this is a kind of lifted re entry.
- [14:39]
Maggie Adairin
But what I find interesting is all this is occurring partly during this blackout phase. So if they need to take manual control or whatever, I guess they're making that decision autonomously.
- [14:49]
Tim Peake
Absolutely. If something goes wrong with the spacecraft at that point, the crew are essentially on their own and Mission control are just simply waiting to try and reestablish communication. And that must be quite a nerve wracking moment for Mission Control. It's actually more comfortable in the spacecraft. You're not too worried at that point. You're simply worried about yourself and the spacecraft. You're not worried about the communication with mission Control.
- [15:11]
Kristen Fisher
But for everybody listening, everybody waiting, this might feel like the longest few minutes of the entire mission.
- [15:17]
Maggie Adairin
Eventually, communications will return revealing that integrity has survived peak heat.
- [15:23]
Tim Peake
Yes. And soon after that comes what I think is the most important part of the mission, because the parachutes have to function. This happens in a number of different ways because at first there are three forward bay cover parachutes. These come out and these actually pull the forward bay cover away from the spacecraft and that's protecting the rest of the parachute system. From that heat of re entry. And then two drogue parachutes come out. And these parachutes, they slow and stabilize the module and that brings the speed down to about 150 miles per hour. And then three pilot parachutes come out, and they're quite small as well. And their job is to actually pull out the final main parachute. So these three massive orange and white striped main parachutes, they're the ones that we're going to be really watching for. They're the ones that are going to be most visible for us. And that will slow this whole spacecraft down to about 20 miles an hour. And that's the moment, I think, that most people breathe a sigh of relief when they see those three lovely, massive
- [16:27]
Kristen Fisher
main parachutes and that violence of re entry that we were talking about. The fireball. Right. Once those parachutes open, it really gives way to a much more gentle descent. Just a very. A very comfortable 17 miles per hour. That's quite the slowdown from what they were doing.
- [16:46]
Tim Peake
Yeah, absolutely. And in fact, I was talking there about the dynamic element. And during the re entry process, the most dynamic, and by this I just mean violent, is when those drogue parachutes come out. Because the drogue parachutes, your spacecraft's still going quite fast, and these parachutes sometimes come out off axis and you get flung around inside that spacecraft quite wildly. It's like the best roller coaster you've ever been on, really. So when those main parachutes do open, you're right, Kristin, that is the moment where you can just have this nice, gentle, calm ride down to the surface. And of course, there's a. They're heading for the water.
- [17:26]
Kristen Fisher
You do make it sound kind of fun.
- [17:29]
Tim Peake
It's a huge amount of fun. It really is. I recommend it to anybody.
- [17:34]
Maggie Adairin
You're selling it well, but I guess. But it's splashdown. So they need to be collected then because they land in the sea.
- [17:40]
Tim Peake
Absolutely. And you know, those main canopies, I think the surface area of those three parachutes, about the size of a football pitch. But then orion weighs about 10 tons at that point. So, you know, you need those three big parachutes to slow it down. But by coming into the ocean, you also have that slightly softer landing than, for example, we had in a Soyuz on hard ground on the steppes of Kazakhstan. We needed small rocket thrusters that fire at 1 meter off the ground and they just cushion the blow a little bit for that last bit of the landing. So I've never splashed down. I'd love to try it.
- [18:14]
Kristen Fisher
You know what, I just realized that I'm dressed like one of those main parachutes today. Didn't even plan it for our listeners. I've got an orange suit jacket on
- [18:21]
Tim Peake
and a white shirt.
- [18:23]
Kristen Fisher
I'm going to thought about changing now. I'm gonna keep this on all day. This is my lucky splashdown attire. All right, what do we say we get to some questions from the audience?
- [18:33]
Maggie Adairin
We have one here from Megan. How does weather factor in? Does splashdown location have to change if there's a storm and how would they do the change?
- [18:42]
Kristen Fisher
I think the answer there, Megan, is yes, weather absolutely affects the splashdown location and it's not just for the Orion spacecraft. We see this when SpaceX's Crew Dragon capsule splashes down. Back on Earth, weather is a huge factor and wave height in particular is a big factor. It has to be less than six feet. I mean, just imagine you've been up in space for 10 days now, you've been experiencing these high G forces on re entry and then you splash down and you're getting tossed around in these waves. You know, I mean, we've heard the stories about the Apollo astronauts getting a little bit sick in some of those waves. So wave height is a big deal. Winds have to be under 25 knots in order to safely deploy the small recovery boats. There can't be any rain or thunderstorms within 30 nautical miles. So the weather team is really working hard to make sure they've got all of their forecasts as dialed in as possible. And then the deploy boats are going to come in, the rescue ships essentially. And you know, Tim and Maggie, I had the pleasure of watching the Artemis II crew about a year and a half ago train for this recovery in the big pool at NASA's Johnson Space center where there was a mock up of the Orion spacecraft floating in the pool. They brought in these Navy teams that were going to help them get out and it was unbelievable the amount of precision that goes into something like this because little things like you want to make sure that this little hook or strap on their spacesuit doesn't get caught as they're trying to crawl out. I mean, every little thing is right, rehearsed and re, rehearsed and practiced just for this moment.
- [20:22]
Tim Peake
Meticulous attention to detail. And I know we've said this before on the podcast as well, but it's interesting to note that the Translunar injection nearly 10 days ago, now part of the go no go for that was the weather. You know, those long range weather forecasters at NASA, they were looking all the way out till tonight to the weather in the Pacific to make that decision. Are we going to have good weather for splashdown before we send this crew on their journ to the moon? So let's see how good those forecasters have been, but I think it's looking okay right now.
- [20:55]
Maggie Adairin
Thank you so much, Megan, for sending in your question.
- [20:58]
Tim Peake
Now, space exploration involves a lot of extreme temperatures and stresses, from liftoffs to landings and from touchdowns to traversing. All of the materials involved need to be carefully thought about, particularly if you're hoping to build structures using lunar soil, for example. Now, we're delighted to welcome to 13 minutes from the BBC World Service, Dr. Philip Metzger, Director of the Stephen Hawking center for Microgravity Research and Education and co founder of NASA Swamp Works. Thanks for joining us, Phil.
- [21:28]
Dr. Philip Metzger
Hi, glad to be here.
- [21:37]
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Tim Peake
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- [22:40]
Tim Peake
Well, it's great to have you with us and we've got a lot to talk about, but I wanted to mention avcoat first. And avcoat is this ablative material that's used to shield the bottom of the Orion capsule from that heat of re entry that we've been speaking about. And it goes back to the Apollo design. It was also used on Artemis I. And of course, it's now on the Integrity spacecraft that our four astronauts are traveling in. And there were some question marks after Artemis 1. And our listener Dave, along with many others have asked what changes, if any, have been made to the heat shield since Artemis 1?
- [23:15]
Dr. Philip Metzger
That's a great question. So, yes, the AVCO does have a heritage that goes back into the Apollo program, but it's been a long time since Apollo, and some of the materials that went into AVCO can't be used anymore. So they've had to replace those chemicals. And that resulted in a slightly different material. It has different properties. And we now realize that it's a little bit less permeable to gases than the Apollo AVcode was. And when you're coming in in hot re entry, you're ablating that material to carry the heat away. Ablating means it's breaking down at the molecular level and being sloughed off. Well, that also produces gas inside the material. And that gas builds up pressure and it has to get out through the permeability of the material. So the other change we made from Apollo, one of the other changes is that we're now not doing a direct entry, it's doing a skip entry. So there's two periods of higher heating. And it turns out that during that intermediate time, you're not sloughing off the exterior material, so the gases inside are more trapped, but you're still generating those gases because it's still hot enough to do that. And that caused a problem with Artemis I blowing off chips of material. So we didn't have enough time to change the avcoat for Artemis ii. But they could address that second change from Apollo. They've changed the RE entry. We're still going to have a skip entry, but they've redesigned it so there will not be this longer period of ash building up on the surface, keeping the gases trapped in. And they've done extensive modeling. They were able to reproduce this problem in the laboratory. And the modeling agrees with the experiment, which is a good indicator that we understand the problem. And so the new trajectory has been shown through the modeling to avoid this problem and to create even more margin than we had in Artemis 1.
- [25:23]
Tim Peake
I think it might be helpful, Phil, for the listeners to we've mentioned about this Skip entry. Skip RE entry. If you could just describe a bit about what is a skip RE entry and how and why is it different to the Apollo spacecraft?
- [25:37]
Dr. Philip Metzger
For example, in Apollo, they came in directly without the skip. And so the astronauts on board experienced about 6.8 GS, which is really high. And I mean, I've only experienced two GS in the NASA reduced gravity aircraft. And two GS for 40 seconds is pretty intense, but I can't imagine 6.8 GS for 13 minutes. So in Artemis, they had the idea that by using the aerodynamic lift of the vehicle, they could spread out the heating period and create more margin in the performance of the heat shield. And it would also reduce the stress on the crew. However, they didn't realize this problem that it created by having this intermediate period between the two skips, it actually caused a problem with the heat shield. So one approach would be to do the more direct entry. Don't use the aerodynamic lift to bounce back out of the atmosphere and then come back a second time. However, that would be a major change at this point in the program. And they were able to find a subtle change in the trajectory that could reduce that intermediate period. But also it still is going to be a skip re entry.
- [26:54]
Tim Peake
Okay, so the advantages are that it's easier for the crew, less punishment, less G forces, and you spread out that thermal loading on the heat shield over a longer period of time. And I guess also because you're exiting the atmosphere, then back into the atmosphere for a second time, you can extend the range of possible landing sites as well.
- [27:14]
Dr. Philip Metzger
I think that's correct. You do get more downrange and cross range authority because you're utilizing the aerodynamic lift of the vehicle over a longer period of time.
- [27:24]
Kristen Fisher
Phil, going into this mission, this very issue, the heat shield was arguably the most controversial aspect of the entire Artemis 2 mission. Profile and architecture and design. There were some people who thought that astronauts, humans should not fly on this mission, that the spacecraft should be tested one more time in an uncrewed test flight. Because of the extensive damage to the heat Shield in Artemis 1, even just as recently as when the new NASA administrator, Jared Isaacman came into office, he convened a big meeting with a bunch of experts to see if he felt comfortable with keeping humans on board this mission. And in the end, obviously, he did. I'm just curious where you fall down on this debate. How confident are you that this heat shield is going to hold on re entry?
- [28:12]
Dr. Philip Metzger
It's a tough question, but that's the way it is in spaceflight. There are a lot of tough questions. And we could never fly a perfectly safe mission. The safest mission is just staying home in bed. So we're always making decisions about is this safe enough, and considering the economics and the political environment and the value we get from the mission, are we willing to take this risk? So this was a judgment call. I understand the concerns. I know some of the people that were very vocal about it. I know one of the astronauts who was in that hearing with Jared Isaacman. I understand their concerns. But I do have faith in the team that has studied the problem, I've reviewed the results of their analysis and their rationale. I know Jared Isaacman is a fantastic administrator, and so I do have confidence that they're making a solid decision. However, I will just say, you know, space flight is inherently dangerous. And so we're, we're all going to be on the edges of our seats during entry.
- [29:17]
Maggie Adairin
So we're looking forward to a safe splashdown. But looking at the Artemis program in general and longer term, a lot of your work is about the materials for construction techniques, and it's looking to sort of buildings and launch pads on Mars maybe one day and also on the Moon. Does the long term ambition for the Artemis program help us realize some of this with your work? And will we be mixing a lunar regolith in with any materials so that we can actually limit the amount of stuff we need to take out into space?
- [29:47]
Dr. Philip Metzger
That's exactly the right way to describe it. The problem with trying to do construction on the Moon is that it's incredibly expensive to transport concrete to the moon. And you know, the cost of the concrete would be entirely transportation costs. But the Moon has plenty of aggregate that could go into concrete. It just doesn't have binders. The geology on the Moon has not produced clay type materials because there's no hydrology on the Moon. And so if we wanted to create binders for a concrete, we would need to have big vats of chemical processing to change the silicate materials into something like Roman concrete. And that's possible, but the amount of infrastructure would be excessive. And so we've looked into alternatives like bringing a polymer from the Earth. And we've actually done calculations that show once the transportation cost to the Moon goes below about $23,000 per kilogram, then it'll be cheaper to bring the polymer from the Earth than to do the other methods. But it's still a long time in the future before the transportation costs are that low. You know, they're, they're currently about a million dollars per kilogram. Wow.
- [31:02]
Maggie Adairin
So it's got a way to go.
- [31:05]
Dr. Philip Metzger
You have a ways to go. So we're looking at things like using microwaves or heating the regolith in an oven to create pavers. The problem with creating pavers is then you have joints between the pavers and the rocket exhaust gas when you're landing on it can blow into those cracks and explode the landing paddle pad. And we've seen that happen in tests where we actually explode an entire landing pad because the gas went between the Cracks. So it's a more complex construction operation to use pavers with grout and make sure all of that will be reliable.
- [31:39]
Tim Peake
And what about construction material for habitation, Phil? So, I mean, obviously there's, there's making kind of landing sites and launch pads. But is the lunar regolith any good for radiation protection, for example? And could you use that in some way to shield your habitation modules?
- [31:57]
Dr. Philip Metzger
Yes, it is, with a caveat. If you have too thin of a layer of regolith, it actually makes the radiation worse. And that's because the heavy elements in the regolith, including iron, will be shattered by the cosmic ray particles. And then you end up having the energy of the cosmic ray split into multiple fragments of that nucleus. So you've got more of them and they're going slower. And because they're going slower, it's actually more dose to the crew, a higher probability of being absorbed in your tissues. So a thin layer of regolith is not a good radiation shield. People argue how thick is thick enough? The optimists say 1 meter, the pessimists say 10 meters, which is basically going, wow, wow. Consensus is around 2 to 3 meters. But for short term, 1 meter is fine. So, yes, we want to use regolith for radiation shielding, also for micrometeoroid shielding, but it's not adequate as a complete construction material because you need to maintain the air pressure inside the habitation unit. And so it has to be a combination of materials to build that.
- [33:06]
Maggie Adairin
What I love is that the Artemis II is the path that is leading us that way. And we sort of are watching all this sort of pan out, but it's like, it does feel like the start of something glorious.
- [33:15]
Dr. Philip Metzger
Oh, I totally agree. I'm thrilled. This is what we've been waiting for for 50 years. In fact, I want to say that the fact that we had humans flying around the moon taking photographs turned out to be vastly better for science than I thought it would be. Because having a human in the loop making those decisions based on the big picture of what they see, it's better than anything we can do in software or AI at this point. And so everybody I know that wants to do lunar science wants to have humans on the moon so that we can have real scientists making quick decisions and accomplishing 100 times more in a day than what a robot can do.
- [34:01]
Kristen Fisher
Part of the reason that you're so qualified to speak about all of this is because you are the co founder of NASA's Swamp Works. Great name. I think a lot of people have heard about Lockheed's Skunk works. This is NASA's Swamp Works. What exactly is it? And what are the sorts of things that it's, like, studied?
- [34:18]
Dr. Philip Metzger
Okay. Now, people tell me that I was the one who came up with the name Swamp Works, but I honestly don't remember it. But we were trying to copy the Skunk Works. And so we're thinking, well, what is it about Cape Canaveral that's distinctive? And so we finally came up with the idea of the swamp. The marshes.
- [34:36]
Kristen Fisher
It's the gators, right?
- [34:37]
Dr. Philip Metzger
Yeah, yeah. We ended up with a robot alligator as the logo. And I love it. But there were just a bunch of people inside NASA that wanted to do more. We wanted to go back to the moon and Mars. And so we decided, well, we're just going to start working on that. We're going to find a way to make it happen. So we, through a series of really remarkable events, we were able to get a facility. And in fact, NASA won a lawsuit against an aerospace company and got $50 million back. But when NASA gets money from Congress, it has an expiration date, and getting it back in a lawsuit did not reset the date. And so we had to spend the money in just a few months. And everybody in NASA was trying to figure out, how can we spend $50 million in such a short time. And so somebody told me, call this man up and ask him for some money. And I thought, well, that's really awkward. But I had to do it. And I said, can I have some of your money? And he goes, yes. How much do you want? I wasn't ready for that question, so I just made up a number on the spot. I said, $200,000. And he said, okay, done. So I had. I had one month to spend $200,000. The only way to do that was buying equipment. By the way, when people found out I was spending money, they started calling me, do you want another 60,000? Okay. So I spent all the money and bought equipment, But I had nowhere to put the equipment. I had no lab. And so it was all shoved into a storage closet. Well, one day, Jackie Quinn, who's an amazing inventor, scientist and engineer at NASA, she saw me in the hallway and she said, father Phil, did you ever get a room to put all that equipment in? I said, no, they won't let me start a lab. They don't want the ongoing maintenance cost of another lab, so they won't give me a lab. And she said, phil, really, do I have to show you how to do this. And so she took me out in the hallway, and she started looking in the windows of the various lab doors, and she found an empty one. And on every door, there's a number. It says, call this number for entry. And so she called it, and she used her Jedi voice to convince the guy to give her the combination to go into the door. And she said, this guy's going to use the room. He'll only use it for six months, and then he'll leave. And so as soon as she opened the door, she said, write this number down. This is your lab now. They're never going to get you out of here. And sure enough, they forgot I was there. They never asked me to leave. And when they moved our entire organization to a new building, I got this weird phone call. Somebody said, we're trying to collect the requirements for the new facility. The strange thing is, we couldn't find your lab in the database. I don't know how it got deleted, but I put it back in. And so that was how the Swamp Works was born. I love it.
- [37:26]
Maggie Adairin
It's a tale of serendipity, and it's an opportunity.
- [37:29]
Dr. Philip Metzger
So, yes, in Swamp Works, we were focused on developing technologies for the surfaces of other planetary bodies. In NASA, they talk about flight systems and ground systems. They also talk about surfaces systems, and that means for surfaces other than Earth. So it's like ground systems on another planet. And so we were working on the equivalent of spaceport technologies like we had at the Kennedy Space center, but for the moon and for Mars. So cryogenic fuel supplies and landing pads and other infrastructure like that. And that's why we got into lunar construction. And my personal area of research was how rocket exhaust blows soil during lunar and Mars landings. And that's become very relevant now in Artemis. So for 20 years inside NASA, we were fighting to explain why this is a real concern. And after I retired from NASA, suddenly NASA understands it. And so now NASA's working feverishly on all these questions, but I am getting funding from NASA to continue working with them through the university.
- [38:38]
Kristen Fisher
And just explain why that is so important right now for folks that may not understand why is studying what happens after a rocket lifts off from the surface of the moon and Mars. Why is that so relevant?
- [38:49]
Dr. Philip Metzger
Yeah, well, I want to relate this to philosophically why I love planetary science. The reason I love it is because every world has different rules than the Earth. You know, the gravity is different, the atmosphere is different. The radiation is different. And that makes everything, the integrated performance of everything, be different in unexpected Ways. And we never learn how different until we get to that planetary body. And that's why we have to do these missions well. One of the things we learned during Apollo that we didn't anticipate is that rocket exhaust blasts go globally on the Moon. And that's because the Moon is an airless body. There's nothing to slow down the dust and the other fine particles that get accelerated to the speed of the rocket exhaust. Rocket exhaust typically goes faster than 3 kilometers per second. Escape velocity on the Moon is 2.4 kilometers per second per second. So there are particles that go all the way up to and above the escape velocity. And therefore there is no distance on the Moon far enough away to have zero impact of the launch. However, the flux becomes very low at great distance. We just don't know what distance it's low enough because we don't know the physics well. And we don't know how to design equipment to handle the sandblasting. So it's going to be an international issue issue. Nations need to come to agreements about how we can operate near each other to show due regard to each other's hardware and not interfere with each other's operations. And yet to enable robust activity on the Moon.
- [40:24]
Kristen Fisher
Phil, what have these last nine, 10 days been like for you as somebody who has been in the space industry for so long? And I'm sure there were moments where you thought this moment might never happen again, or you hoped it would, but it felt so far away. It's now finally here. Humans are back in the business of going to the Moon. Moon. Just on a personal level, what's it been like for you to witness?
- [40:43]
Dr. Philip Metzger
Well, so for me, it's very personal because I grew up on the Space Coast. My dad worked on the Apollo program. He has the certificate as a team member helping to prepare the rockets for Apollo 11. He was so proud of that. That was one of his greatest accomplishments in life. And so I worked for NASA right out of college. I was there for 30 years. And we were always talking about going back to the Moon and going to Mars, but it just never happened because of political and funding concerns. So to finally see us sending humans beyond low Earth orbit, flying around the Moon, and even going a little bit farther than humans have ever gone before, you know, that's a really meaningful symbol. It wasn't that much farther than they did in Apollo 13. But the fact that we did did says we're now going beyond what we did in the 1970s and 60s.
- [41:38]
Tim Peake
That is utterly fascinating. And I'm sure we could all talk to you all day. Phil, thank you so much for joining us and sharing your expertise. I'm afraid that's all we've got time for today, but it's been great having you on the podcast. Thank you.
- [41:52]
Dr. Philip Metzger
My pleasure. Thank you so much.
- [41:54]
Maggie Adairin
And thanks as ever to you, Kristin for being alongside in the cap.
- [41:59]
Kristen Fisher
Oh, it's been a true pleasure, Tim and Maggie. I'll talk to y' all tomorrow.
- [42:02]
Tim Peake
As a reminder, we've been doing an episode every day for this mission, so do search for BBC 13 Minutes presents Artemis 2 to catch up on this and previous series. And if you're new here then please do subscribe or follow. But that's it for today. This is our last episode before re entry of Artemis 2, so goodbye from
- [42:21]
Maggie Adairin
me, Tim Peake and me, Maggie Derrin. The producers are Alex Mansfield and Sophie Ormiston and the series editor is Martin Smith.
- [42:31]
Tim Peake
And thanks to Hans Zimmer and Christian Lundberg at Bleeding Fingers Music for our
- [42:35]
Maggie Adairin
theme music 13 minutes presents Artemis 2 is a BBC audio science production for the BBC World Service.
- [42:58]
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