Ep. 804: Mission Tech Series: Fairings, Docking & Airlocks

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1:00And not only what we know, but how we know what we know. I'm Fraser Cain. I'm the publisher of Universe Today. With me, as always, is Dr. Pamela Gay, a senior scientist for the Planetary Science Institute and the director of CosmoQuest. Hey, Pamela, how are you? I am staying at a friend's house that has a coffee maker that's like an espresso maker that is far superior to anything I have ever owned. And sometimes being in a house with a superior coffee maker is all it takes to bring me joy.

1:30Yes. I missed my coffee maker. I have like one of those really fancy Breville ones that both grinds your beans and that just grinds my beans. Yeah. Yeah. And then makes me Americanos all day. Which, of course, we've been trying to push as Canadianos while we were in Europe. Yeah. I said, I'll take a Canadiano, please. And they were like, what? I'm like, it's an Americano, but for Canadians. So, I guess I just need to make the pitch again because we're in this campaign to try and encourage everybody to become our patrons.

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3:42Yes. So, instead of setting up an entire space station for every mission, you can just set up a tiny can filled with astronauts.

Connecting spacecraft in orbit

3:50But that takes docking. And today, we're going to talk about what it takes to connect two spacecraft together, how to keep a cargo safe to get into orbit, and how to get in and out of your spacecraft without killing everyone. All right. So, you smashed these three topics together. Yeah. Which I understand, because each one maybe isn't an entire episode. You need all three, or you die. Sure. But it's also not necessarily enough content for an episode each.

4:21Although, we probably could. Yeah. But still. Exactly. So, where do you want to start with this one? Do you want to talk about docking? Because docking is surprisingly unintuitive. We can do that. Docking spacecraft together. Talking about orbits. Talking about being able to maneuver your spacecraft so that you can dock in orbit. Yeah. So, the problem that you run into is, like, we're children of the 80s. So, we watched Knight Rider, at least I watched Knight Rider as a kid.

4:52And I bring this up because Knight Rider in his kit car, David Hasselhoff, who's apparently well-loved in Germany, would drive into the semi-truck with just the right combination of matching velocity, going a little bit faster, and then stopping, which is terrifying, by the way.

5:17And docked into it. And so, to do that, it's fairly intuitive. You just increase your velocity to overcome, and you're going in the same direction. And, like, there's been various movies, and I don't watch enough of this variety, where, like, people are somehow getting out of moving car carriers. And this is what we've seen and seen in video games, is you accelerate to catch up, you decelerate to not die.

5:48But, in space, the problem is, if you accelerate, you're actually changing your path if you're on an orbit. Right. Yes. Yeah. Yeah. You can imagine, like, say you want to dock two cars together, maybe you have big magnets at the front and back of your cars, and there's a car driving down the highway, and you're driving behind that car, and you speed up, and you speed up until you match the velocity of that car, and so now your relative velocity of that car is not that much different, and you get a little bit closer, and you get a little bit closer, and then the magnets connect, and now you are connected together.

6:24But, imagine if you turned on the accelerator, and now your car lifted up above the car that was in front of you. Imagine you put on the brakes, and your car went underground to the car that was behind you, right? Like, it's just, it's super counterintuitive because of the orbits. And the best example for this is, if you've ever watched Olympic cycling, or some other cycle racing, or lucky enough to live someplace with a cycle drone, when you speed up the bicycle, you go up the wall.

7:04And that's kind of the same idea. So, you increase your orbit, and you end up circling around. Right. And speed up the spacecraft enough, and you just head off into deep space. Right. So, they have to think through, we are going to create, our ISS is on a roughly, International Space Station is on a roughly circular orbit. We are going to create an elliptical orbit that, at the moment of docking, puts both spacecraft in the same place, but not at the same velocity.

7:41Yes. Yes. Not at the same velocity. Yeah. So, again, imagine those two cars that are driving down the highway. You know, one is floating up above the other one. Yeah. And so, you are, you know, sort of like, what is the speed that those two could get close to each other without tearing each other apart, you organize that maneuver. Yeah. Yeah. So, it's one of these things where they have to put the pilots through a whole lot of flight simulators. And the poor Gemini astronauts in the days before flight simulators, they had to just get someone who was, like, really good at doing orbital dynamics in their head.

8:20And that is not, like, normal thinking. The wonderful sort of story about the Apollo program was that Buzz Aldrin, the, you know, the second person on the moon, he wrote his, was it his doctoral thesis? Mm-hmm. On orbital docking, orbital mechanics in docking. Yeah. So, he literally helped design the strategies for doing orbital docking. And then had to carry them out on spacecraft.

8:52Yeah. With Neil Armstrong, which is, which is just, and Michael Collins, which is just amazing. That, that, that, that was the, that was the thing that got him on that spacecraft was that he had, in addition to just being all of the other things, the test pilot, you know, the ability to fly, all of this, was he also had, had helped do the math for orbital maneuvers. Yeah. And knew how to make this work. Yeah. Astronauts are something special because they're physically fit, intellectually there.

9:23And you have to be a polymath. So, it's just wild. Have you, we're totally getting rabbit-holing now, but have you, like, sat and talked to an astronaut? Oh, many times. For a long time? Yeah. They're so great. Yeah. You're like, I get it. Right? You talk to one of these astronauts, you're like, oh, I get it. No, I understand now. Yes. Yeah, I see why you're, I see why they chose you. Yeah. Because you are the warmest, kindest human being I've ever met. And they can't wake up ready to murder the world, which is a reason I probably should never be an astronaut.

9:55Yeah, they're in ridiculous shape. Yeah. Well-educated, super ambitious, but also a total team player. Right. It's, yeah, they're the whole package. And then they get to walk on the moon. So, you know. Fair. So, okay. So, you've got this idea of orbital mechanics. Yeah. But then what, but then you have the actual, the hardware, the mating between these, these vehicles. How does that work?

Docking hardware and automation

10:21I, so what I love about this is they refer to them as androgynous and non-androgynous. So, you either have something with a male part and a female part, and I don't know, I actually had to make hand gestures about that. So, I'm going to just stop. Yeah. I'm glad I wasn't watching your actual video screen at this point. I mean, yeah, we're just going to pretend the last 30 seconds did not exist on video. Yeah. Think about, think about network plugs going into adapters.

10:53Yeah. Think about, yeah. And, and one of the things they work very hard to do is have systems where if you start out slightly unaligned, all the edges are rounded and they funnel you into where you belong. And, and it's the idea is you approach, you start to get the couplers together and it's not like a USB. If you're a little bit off, it's okay.

11:23And as you apply pressure, it fixes your direction and then essentially does the moral equivalent of clicking into place so that you are locked there. Do you remember the time when I told you that you were unintentionally filthy? Yeah. Yeah. Anyway. I know. Yeah. Anyway, please continue. Yeah. This is who I, I, how could we not, how could this not be double entendre city as we talk about docking spacecraft? Yeah. Male and male and female docking components as they have to be guided together.

11:55It's together to achieve a docking, uh, maneuver. Yeah. Yes. So I, one of the unfortunate things is there's been a lot of debate on how to do this effectively over the past, what, 50 some odd years since Apollo Soyuz. And, and so even on the International Space Station, there are two different sets of docks.

12:28There's actually three. There's the docks that are used between modules that are U.S. modules. Then there's the, uh, docking ports that are good for Russian and European spacecraft. And then there's the docks that are good for American spacecraft. And for the longest time, the Americans insisted on humans, on the pilots. Right. Doing these docking maneuvers. And Russia has always been. Always been automated. Yeah. From day zero.

12:59It has always been, yeah, they are spamming a can that the, the cosmonauts are not responsible for docking the spacecraft. Yeah. Yeah. The, the Soviets really started that. But, and like, even Buran, their space plane was fully autonomous, which is wild to think about when you consider the power of 1980s computers. The idea of flying a space shuttle as a drone in the 80s is way more impressive to look back on than it was in the moment.

13:32Yeah. But with the Falcon, with, with the, uh, Crew Dragon, we're back to a very high level of automation at this point. Yeah. Yeah. I mean, it really, as you, you know, it really is a complicated maneuver. And that one misstep, one bad rocket firing, and you tear your spacecraft apart, you tear the thing that you're trying to dock with apart. Everything's made of aluminum foil. The chance of destruction is very high. And, and, and one of the things that, that's been really cool is there have been a fair number of cases where they grab something with a Canada arm and then dock it.

14:15And so I appreciate that old school way of doing it. Right. Have it be nearby, reach out with the arm, grab it, and then pull it in. And now you're, it's a, it's a more straightforward docking maneuver as opposed to trying to match the velocities and think about how you're going to raise your orbit as you, as you change your velocity. Okay. So, so how do airlocks work?

Managing airlocks and pressure

14:41So the, I do airlocks, why, why airlocks and how do they work? Like, you, you, you have two different problems that you need to solve. Um, one is you have the air inside the, uh, capsule, and then you have the air inside the spacecraft. Um, sorry, the space station, or if it's two space, you have two different objects with air in them. We'll just go with that. And that air may not be at the exact same pressure.

15:13And so ideally what you want to do is dock to a contained unit. And you also don't want to lose air anywhere because it's a valuable commodity. So you have your airlock, you have thing A and thing B that are pressurized. You fill airlock to match thing A, so dragon capsule, whatever, match the pressures, then match the pressure to the other place.

15:49And so it's kind of like a ship going through a lock where you lower and raise it between different parts of a river. Except in this case, you're lowering and raising the air pressure to get between different vessels without blowing anything out. Now, the other side of the airlock is, while they're absolutely necessary to bring two spacecraft, a space station and a spacecraft, whatever combination of pressurized things you have together. You also need them to exit.

16:19Like if you're going to go on a spacewalk? Yeah. So if you want to go on a spacewalk, you go into the airlock and then it's the same idea. You have to match pressures. So in this case, you close the door to your spaceship. You pull all the air out to match the pressure outside. Which is vacuum. Yeah, but you're going to need the exact same thing on Mars, except on Mars, you are swapping it out to be the same pressure as outside.

16:50If you don't match the pressure, you're going to either get pressure pushing you in if you're too low and slamming you against the wall behind you. Or if it's too high inside the airlock, you get flung outwards. So when you're in an airlock in outer space, you open the door while braced to something in case something has gone wrong so you don't get exited at high velocity, which we've all seen in movies as how they kill people.

17:21We don't do that by accident. So there's a great episode of...

17:28Expanse? Star City. No, Star City. Oh, I haven't watched that. Yeah, so this is the follow-on to For All Mankind. And airlocks play a big role in this TV show for some of the episodes. And you get a lot of just how life and death these things are. That you are, you know, like just a human body. It's just not meant to exist in vacuum. And that we need this cushion, this middle stage that you, you know, you're in your spacecraft, you go into the airlock, you pump out all the, you know, you're in your space suit, you pump out all the atmosphere of that airlock.

18:07Now you're at the same pressure as the vacuum of space, you can go out and do your spacewalk. And then you come back in, you start off at the vacuum of space, you close off the airlock, you fill it back up with the atmosphere so it's the same atmospheric pressure as the rest of your spacecraft. Yep. Open up the door and now you can take off your space suit. And that this process is, it just takes a long time. And, you know, when the astronauts are doing, say, spacewalks outside the space station, it's so laborious to go through this process of getting themselves into their spacesuits, getting in, you know, while they're floating around in the station, getting into the airlock, depressurizing it, going on their spacewalk.

18:50They make their spacewalks really long. Like they don't just pop outside. No, no. It is an event. It's grueling because, I mean, imagine you get something on your face inside your helmet or like, I've never seen this in a book, but it is one of my personal, that would be horrifying. Imagine an eyelash falls into your eye while you have a helmet on. There is nothing you can do. Nope. And now you're outside for eight hours.

19:23Yeah. Or your water tube goes wrong. And, yeah. Yeah. There's no way to pull your arm inside. No. Reach up, you know, fix your eye. Yeah. Get your arm back down into your, into your arm, into your suit and keep working. Yeah. You're stuck. Yeah. Things, things I worry about. Yeah, totally. I have no reason to. And yet, here we are. So let's talk about the third piece of this conversation that you included, which is pharynx.

Rocket fairings and cargo protection

19:57So, probably should have done this in a different order, but that's okay. So, when, when you're taking off, there is this, this mismatch between the shape of whatever you're trying to launch, unless you're launching your capsule, and the shape that is necessary to get through an atmosphere without things going terribly, terribly, frictionally wrong. So, you have the nose cone, which is shaping how air flows over your rocket, and then you have the shape of the body of the rocket.

20:36And those can take on different shapes. Some of them have that weird, they're extra large at the top, and some of them are just, like, straight down the sides. So, more like a hydro flask coffee cup with, like, a nice rounded cone on top. A spacecraft is going to be shaped more like a box with solar panels attached to it. Right. And the solar panels are completely folded up. Right. So, you basically have a box with boxes attached to it. That is not an aerodynamic shape.

21:09Right. A box with flaps attached to it. And if you're doing a rideshare, you have a box, and then you have 30 other boxes, and they're all in something that looks like a piece of jungle gym equipment. Right. And that is a really not aerodynamic shape. A metal rack. Yeah. And really, I mean, escaping the gravity of the planet is the hard part. Yeah. But the aerodynamics are definitely a factor, and you want to be as streamlined as you can. And if you're not aerodynamic, you tear yourself apart.

21:40This is, unfortunately, something an airplane learned last week. We're not going to go into this. But an airplane that dropped about 15,000 feet in 30 seconds, its rudder tore off. Like, no more rudder. Rudder gone. That was aerodynamics. So, we don't want to do that in general, that idea. So, what they do instead is they enclose in, and there's a variety of different ways that they've done this over the decades, they enclose that jungle gym of equipment inside nice, smooth panels that fit together.

22:18And sometimes they open up like a flower. Sometimes they explode themselves apart and fly away. Whatever the mechanism is, these beautifully fit together panels release the inside cargo so that it can fly free. And they don't always do all of this at the same time, especially when there's that jungle gym of additional satellites, a transporter of some sort inside. So, they'll release the fairings, and now you have a new enclosure that often has some of its own engines that's just releasing things as it goes.

22:53So, fairings serve one purpose, and that is to keep your thing safe from air pressure and to make your rocket more aerodynamic. And what's cool is the need to have fairings is driven by the atmosphere. So, in the Martian, they actually had to reduce the weight to get off of Mars. And so, instead of having full-on fairings, they used a tarp. And I think it was a tarp, if I remember correctly. Yeah, yeah, yeah. Yeah, it was a tarp. And that was because that was all they needed with Martian thinner air.

23:28But it was still scary. Yeah, it's terrifying.

23:32And, you know, one of the things that's fairly interesting is that SpaceX has been trying to – was trying to reuse the rocket fairings. And they're getting a lot of reuse out of those. Yeah. And so, originally, they were trying to capture them before they even touched the water. Yeah, they would have them, like, with a parachute, and then they would fly down, and then they could try to sort of chase underneath them and then try to catch them. Yeah. And in the end, it turns out, you just let them hit the water, and then you just retrieve them out of the ocean and clean them up, and they're fine.

24:05You can use them again. And with Starship, the plan is that the – like, right now, Starship is deploying its Starlinks out of this Pez dispenser slot. But eventually, they're hoping to have a big old chomp-chomp Pac-Man maw that opens up on Starship. I had not read that yet. Yeah. So, think of, like, a whale, like a whale feeding on krill, right? So, the thing will open up this huge fairing, spit out whatever stuff is inside of it, and then close it back up and then return.

24:41And so, you don't always have to ditch the fairing. But normally, in the olden days, you would ditch your first stage, you'd ditch your second stage, and you'd ditch your fairing. But really, the only thing that made it to space and survived was the actual payload. Everything else was fine to be disposed of. To be clear, there is a whole lot of empty second stages in space. Yes. Yeah. But what's cool is a lot of the ideas from how do you build a small, low-cost observatory that opens up to reveal your telescope, and how do you build low-cost fairings, a lot of the same mechanical ideas get reflected in both.

25:28And that just amuses me. And I can't tell you why it amuses me, but it does. I wonder, though, you think about, say, aeroshells, and we're probably going to talk about this at some point, but they're sort of like fairings in reverse. Yes. Right? That essentially, you need the fairing to get you up out of the atmosphere, where you are starting off at zero and then accelerating up to get yourself out to orbital velocity. And then you can ditch your fairing. And then in reverse, with the aeroshell, with the heat shield, you are hitting the atmosphere.

26:00Instead of you trying to make yourself aerodynamic, you're just trying to spread the heat coming from the interaction with the atmosphere around. And that the shape of the fairing, the shape of the heat shield changes depending on where you're going. If you're going to Mars, if you're going to go to Titan, different shapes. Go to Venus, different shapes. So it's a totally different, totally different world. But, you know, we'll talk about that later on, I'm sure. Very cool. Was there anything else you want to talk about of this episode? No, that was it.

26:31Okay. All right. Well, thank you, Pamela. Thank you, Fraser. And next time we record, you're going to be in yet another country. Or back in Canada. Oh, okay. For some reason, in my head, your trip to... I will be very long. Okay. Okay. Yeah. Yeah. This one is just a little over a week. Oh, cool. And then in November, we, quite by accident... We meet up in Japan. ...are both going to be in Tokyo at the same time.

27:01Yeah. Maybe. Yeah. Probably. I haven't figured out my schedule yet. But, yeah. All right.

Patron shoutouts and credits

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