Mike Meacham :

I’m Mike Meacham. Yeah, that’s a photo of me at work at JPL. It’s a NASA center in California called Jet Propulsion Laboratory. We’re known for robotic exploration of the solar system. We like to figure out what our solar system is made of, and since it’s so difficult, at least with today’s technology, to send people, we send robots to do it for us. They sample other surfaces of planets and they send us back the information. One of our favorite places to go is Mars. We love sending things to Mars. We send primarily rovers to Mars that can actually wheel themselves around. Some of you guys have probably seen Curiosity. It’s up there now. It’s been up there for years now, taking good samples of the soil and sending us back data. It is difficult to land things on Mars. When we approach the planet, we’re going more than 10,000 miles per hour, if you can get that in your heads. It’s extremely fast.

Mike Meacham :

And our job at JPL is to go from 10,000 miles an hour to zero miles an hour. That’s it, and you have to do it in about seven minutes. Otherwise it’s game over. You’ll hit the surface way too hard. So I want to show you a part of this very complex sequence now. There’s an animation that shows how Curiosity landed. There is a huge parachute deployed, slowing our spacecraft down. The next thing we do is kick the heat shield off, exposing the rover to the surface, so it can actually start seeing it. The rover slides out of the back shell, and we fire up our rockets and it’s actually a rocket powered elevator that lowers the rover down to the surface. We call this a sky crane maneuver. It gently, fingers crossed, deposits the Rover onto the surface.

Mike Meacham :

We cut away that elevator portion and it literally flies away and destroys itself, and the last thing, the only thing that hasn’t crashed landed, is the rover itself. It’s a very complicated sequence. The scariest part of that, at least for me, and a lot of people I work with, is that parachute inflation. The parachute is really big. It has to inflate at about a thousand miles per hour. You don’t find that very often here on earth, and it has to take enormous amounts of force. The parachute weighs about a hundred pounds, but it has to take 60,000 pounds of force, if you can get that in your heads. It’s a lot of force. If it fails, we crash. It’s as simple as that. We only have one parachute. There’s no time to change things up. This is all autonomous, which means we can’t talk to it, it has to do it on its own. So it’s deploying the parachute when it thinks it’s right to deploy it, and if it bursts it’s game over.

Mike Meacham :

So what that means for me and my team is that we have to test this parachute. We have to test it really, really well so we gain confidence that it won’t break at Mars, and that can be really tricky. I want to talk about testing parachutes a little bit today, but before we get into testing, let’s learn a little bit about parachutes themselves. So you probably noticed this ridiculously big fan behind me that I brought. It’s a really high powered fan and it’s going to help us learn how parachutes work a little bit. I brought three parachutes with me today. The big difference between them is their size. So I’ve got a little tiny one. I got a medium sized one, and some of you can probably see, I’ve got a very large one on the stage here. What I want you to pay attention to, it’s going to be hard to hear my voice once we get the fan turned on, but what I want you to pay attention to is how the larger parachutes cause more force.

Mike Meacham :

The fan is at one speed, same wind. Bigger parachutes, much more force. So with that in mind, let’s fire up this fan and we’ll start playing with parachutes. Okay. The little parachute. It’s a NASA Teddy bear. Not hard to hold on to.

Mike Meacham :

Medium parachute. Wow. That’s a lot more force. So should we test the big one?

Speaker 2:

Yeah.

Mike Meacham :

Okay. For the big one, I’m going to need help, because it’s a lot of force. Same fan, big parachute. It’s going to bring in people. We need four people to hold this thing down. Okay. Ready? Thanks. Awesome. Okay. So that’s a big parachute. These guys are working hard back here. I’m going to see if I can get them just to walk forward a little bit so you guys can touch it. Guys, you want to come forward together? So you can feel free to touch it. It won’t hurt. It’s just nylon, like you find in a camping tent it. Bring it back, and let’s kill the fan. All right.

Mike Meacham :

So everyone gets the basic idea. Bigger parachutes, more force, not so hard. Our Mars parachute is about twice the size of that parachute, and that’s the one that landed Curiosity. What we basically just saw here was a wind tunnel test. We just tested three parachutes, not to super high forces, but they’re tested. We know they work somewhat. But for Mars, we need to do a lot better than that. So for Curiosity and previous missions, we’ve gone to wind tunnels. There are wind tunnels in this country that are much larger than this room. Thousands of times more powerful than that fan, and they can blow wind at a hundred miles per hour, consistently down a huge tunnel, and we can inflate our parachutes and test them to the same forces that they’re going to feel on Mars.

Mike Meacham :

Now, you heard a hundred miles an hour and a thousand miles an hour. What’s going on? The atmosphere at Mars is very, very thin compared to what you’re feeling in this room. Now this air is like molasses compared to the air on Mars. It’s very thick here. So when a parachute inflates on Mars at a thousand miles an hour, it produces a certain amount of force. And to reproduce that force here on earth, you can go slower and get the same amount of force, and we use that to our advantage in testing. So a thousand miles an hour at Mars, equals a little less than a hundred miles an hour here at earth. Here’s the big problem. We want to land bigger things on Mars, which means, inevitably, you need bigger parachutes, and the problem we’re running into is that these bigger parachutes don’t fit in any wind tunnel that exists today.

Mike Meacham :

And it’s very expensive and complicated to build new wind tunnels. We have to test these parachutes. Everything’s riding on them. This was the question posed to me and my team. They said, “Find a way to test this parachute, even though you can’t use a wind tunnel.” So what would you do? How do you pass a hundred mile per hour wind over a parachute if you can’t use a fan, you can’t use a tunnel, and you can’t build a tunnel. We don’t have the money to build a new tunnel. So we started drawing on the whiteboard. We came up with all kinds of crazy concepts, and long story short, I’m going to show you guys what we eventually came up with. It starts with a helicopter, a very cool Nighthawk helicopter.

Mike Meacham :

Right now it’s picking a parachute up off the ground. It’s inside of a bag. At the bottom of the bag is a kilometer of rope. This rope weighs 3000 pounds. The whole kilometer is stretched across the desert floor. The helicopter flies up a kilometer in the air. The pilot releases the parachute and we start spooling in that rope with a high horsepower winch, a 300 horsepower winch, you can see up the top of this video here. So we’re maintaining tension in [inaudible 00:07:13] and we pull the parachute down, we pull it down and we latch it up to the back of a rocket sled, a sled that’s powered by huge rockets. Hundreds of thousands of pounds of thrust. What’s going to happen is that winch is pulling it down. It’s going to latch up into the back of the sled and it’s going to automatically trigger the rockets to pull the parachute around a pulley.

Mike Meacham :

Boom. So that sled starts taking off. That’s a huge sled. It’s over a hundred feet long, more than a hundred thousand pounds of weight. We had to pour two million pounds of concrete in the ground just to hold this parachute in place, and you can see we’re getting over 90,000 pounds of force on this parachute. You’re probably also noticing the parachute ripped. “Oh no, we’re going to crash at Mars.” That’s why we do this test. That’s why it was so important to come up with it, is that if we don’t do a test like this and we just think we have the parachute figured out, we will fail a mission. So it’s important to figure that kind of stuff out. So, that’s what I do in my career. I think of crazy ways to test our technologies.

Mike Meacham :

If you’re curious about where I came from, how I got into this sort of career, I’ll tell you a little bit of the background of myself. I studied mechanical engineering at school in college. To me, mechanical engineering just means you’re using the things you learned in science and math and applying it towards building something. It’s as simple as that. Don’t just build it and guess. Use your formulas. Use the things you’ve learned in class. And you’re much better off that way. So what did I build in school? I always loved building things that I could ride. I like building things that no one had built before, that I could get on somehow and go for a ride. So I love mountain biking. There’s me on my mountain bike, and I wanted to see, in college, if I could ride a skateboard down the same trail as my mountain bike was on.

Mike Meacham :

So I built this off-road skateboard. I’m hurting myself in this video pretty badly, and it worked great, and I loved building that kind of stuff. Another thing we do for fun, sometimes, my friends and I, we try to come up with really crazy concepts. Also, we’re engineering these things. Here’s four weather balloons we inflated. We strapped it to a climbing harness and I jumped off a roof with that, and it’s safe. See? I’m okay. And the reason I’m okay is because I used all those formulas. We knew the buoyancy calculations. We knew the drag forces. We knew how to keep ourselves safe. So, that’s the nutshell about what I do in my career. If that kind of thing interests you, just pay attention in math and science. That’s all you got to do, and just keep trying hard. Thank you for the time.