From The Physics Of G-Force To Weightlessness: How It Feels To Launch Into Space

This episode delves into the physics of launching into space, detailing the journey from the intense forces of liftoff to the serene weightlessness experienced in orbit.

1. Intense Physical Experience: Launching into space subjects astronauts to extreme g-forces, feeling much heavier than on Earth.
2. Surreal Visuals: The curvature of Earth becomes visible, providing a breathtaking perspective from space.
3. Weightlessness Explained: Once in orbit, astronauts experience weightlessness, described as a constant state of free fall.
4. Environmental Concerns: The episode highlights concerns about space debris, which is becoming an environmental issue similar to pollution on Earth.
5. Scientific Foundations: References to Newton’s laws and discussions with experts provide a foundational understanding of the physics involved in space travel.

1: Introduction to Space Camp

Regina Barber and Emily Kwong introduce the series and the focus on space phenomena, setting the stage for a detailed look at space launches.

2: The Physics of Launch

Explains the basic physics of rocketry using analogies and historical references, providing a clear understanding of how rockets overcome Earth’s gravity.

3: Experiencing G-Force and Weightlessness

Wendy Lawrence shares her personal experiences with the physical sensations of launch, from intense g-forces to the marvel of weightlessness.

4: The Problem of Space Debris

Discussion on the environmental impact of space debris, drawing parallels to Earth-based environmental issues and exploring the need for sustainable practices in space exploration.

1. Educate about Space: Learn more about space and physics to better appreciate the complexities of space travel.
2. Support Sustainable Space Initiatives: Advocate for and support policies and technologies that promote the sustainability of space activities.
3. Engage in STEM: Encourage educational and career paths in STEM to contribute to future space exploration solutions.
4. Promote Responsible Innovation: Support companies and initiatives that prioritize long-term environmental considerations in their space ventures.
5. Stay Informed: Keep up with space news to understand how international policies and technological advancements are addressing space debris.

It feels like this is the summer of space launches. So, it's only appropriate that we kick off our new series Space Camp with a look at space launches. Throughout the series, Regina and Emily will plumb our universe to uncover the strange, wonderful things happening all around us. This episode, that entails answering a series of questions about getting to space: What does hurtling into space feel like? What physics are involved? And what's the "junk" in Earth's orbit?

Space Camp episodes drop every Tuesday in the Short Wave feed in addition to our regular episodes happening every Monday, Wednesday and Friday.

For a full explainer of Newton's third law of motion, g-forces and visuals on his cannonball thought experiment, check out our digital story.

Have a particular aspect of space you want us to cover in a future episode? Email us at shortwave@npr.org — we'd love to hear from you!

People

• Wendy Lawrence, Moriba Jah

Companies

• NASA, University of Austin, Texas, Privateer, Guyverse Limited

Books

• None

Guest Name(s):

• Wendy Lawrence, Moriba Jah

Content Warnings:

• None

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Short Wave Host
You're listening to short wave from NPR.

Regina Barber
Hey, short waivers. Regina Barber here with some exciting news. All summer long, we'll be reporting out a new series we're calling Space Camp. Every Tuesday for the next nine weeks, me and my co pilot, Emily Kwong.

Short Wave Host
Hi, Gina.

Regina Barber
Hey. We're gonna travel deep into space. M. Yeah. And we're gonna explore all of the wild, inspiring phenomena in our universe, like different kinds of planets, stars, and even black holes.

Short Wave Host
And we're starting right here on planet Earth with launch to quite literally launch our series. And also because there's been a lot of launches into space recently. In just the last week, there was Boeing's starliner, then there was SpaceX's starship, which was crew less and a bit more of a test.

Regina Barber
Yes. So let's buckle up, Em, and let's start our launch of this series.

Launch is something that Navy captain and NASA astronaut Wendy Lawrence is very familiar with. She was an astronaut from 1992 to 2006, and her first launch was in 1995 on the space shuttle endeavor.

Wendy Lawrence
Launch is one of those things that you always look forward to.

Regina Barber
It never got boring, she remembers as a very surreal experience.

Wendy Lawrence
The moment that really kind of crystallizes it for you is when all the engines cut off and suddenly you're kind of thrown forward in your seat, up against your restraining harness.

You have a view out the window, and you're like, wow, look, the earth really is curved.

Regina Barber
Wendy said it was a beautiful view, but that she couldn't really fully take it in. In that moment, you would think you.

Wendy Lawrence
Would have more of an opportunity to just really savor the fact that, oh, I'm in space. This is awesome. You unstrapped from your seat, and instantly you're not very coordinated.

Regina Barber
And so with the help of Wendy and many other experts, were about to boldly go where few have gone before to outer space.

Short Wave Host
Today on the show, we launch short wave gets into the basics of a launch, from the physics to the weightlessness experience, and we ask why. There is an increasing amount of things to avoid once you reach earths orbit, youre listening to short wave, the science podcast from NPR.

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Regina Barber
Ok am let's get more into what it takes to launch a rocket with astronauts into space. Yes.

Short Wave Host
Ok. So for answers on just a basic physics level, I reached out to Mauriba Ja. He's a professor at the University of Austin, Texas, co founder of privateer and Guyverse Limited, and an astrodynamicist.

Regina Barber
Academics speak for somebody that studies how things move in space, correct?

Short Wave Host
Yeah. And he threw it all the way back to 1686.

Moriba Jah
There's this dude whose name's Isaac Isaac Newton.

He had a few cool things to say, and one of the things that we can attribute to his work was a set of laws of motion.

Regina Barber
Yes, I know those three laws very well. The law I think he's gonna talk about is that for every action, there's an equal and opposite reaction. Right? That's Newton's third law. So imagine you blow up a balloon, hold the end, then you let go. What happens?

Short Wave Host
The balloon should, like, move away from us.

Moriba Jah
Yeah, but it's because the air in the balloon is going towards us and the balloon itself is moving in the opposite direction. It's very similar to a rocket.

Regina Barber
So, em, here's another example. So in physics 101, I used to do this demo when I teach in university, and I would sit on my knees on this like plank thing with wheels that mechanics use to go under cars. And I would put a fire extinguisher between my knees. I would like, let it rip, and then it would shoot me backwards as it fired.

Short Wave Host
That sounds so fun.

Regina Barber
Yeah. So, basically, the rocket has mass, it has fuel. And by this law, Newton's third law, the fuel goes out, and that's what's known as exhaust, and it generates power known as thrust. And we go up in 54321.

Short Wave Host
Lift up.

Gina. Escaping Earth's gravitational pull is not easy, right?

Regina Barber
No, it is not easy. We're overcoming the curvature of space time itself. Like, just a reminder the fabric of our universe. Space time can be thought of as, like, a bendable sheet.

The mass of Earth is making that flat fabric of spacetime curve down into this, like, funnel like shape. Moving up the funnel, escaping Earth's gravity is more difficult than moving down. So we need to go really fast.

Moriba Jah
You need to have enough velocity to be able to no longer succumb to the curvature of spacetime based on the Earth's presence.

Regina Barber
And as all this is happening, the people inside the spaceship are experiencing intense g forces. M. So, gravitational forces, or g forces, come when your body experiences acceleration.

So when you're sitting or walking around on Earth, you're probably not noticing them, even though you're always getting this pull towards the center of Earth or earth's gravity, and that's one g. When you're doing something like going up in an elevator, like, really fast, you feel heavier, and that's more than your regular one g, but it's nothing compared to, like, what astronauts experienced during launch. Like Captain Wendy.

Wendy Lawrence
I remember on my first flight thinking, oh, my gosh, somebody just sat down on my chest. This was an incredibly heavy sensation.

Then I tried to see if I could put my arm out in front of me, just extend my arm, and I'm like, no, I cannot hold it out there against this tremendous power and acceleration being produced by this amazing space vehicle.

Regina Barber
The g forces Wendy experienced were so intense because the acceleration she was feeling was actually three times the gravity we feel on Earth. And, of course, like, once the rocket reaches space, almost nine minutes later, she feels almost weightless. Wendy says that once she got past that uncoordinated stage of floating, it's just awesome.

Wendy Lawrence
You're just perfectly suspended right in the middle of the air. And what's really fun about it is it doesn't take any effort on the part of your muscles or your body to maintain position in front of a window and watch the world go by.

Regina Barber
Something that's actually really cool to me about weightlessness is it feels like you're floating. And astronauts kind of are when they're in the International Space Station. But in physics terms, you're actually very slowly falling towards Earth.

Short Wave Host
You're falling?

Regina Barber
Yes.

Short Wave Host
That's so bizarre. Do you feel like you're falling?

Regina Barber
Yeah, I asked Wendy that, and she said, for her personally, no, I've never.

Wendy Lawrence
Had that falling since. And sometimes you'll hear people who have had the opportunity to go out and do a spacewalk. They'll get that sensation when they first open the outer hatch of the airlock and now are typically looking down at planet Earth.

Em.

Regina Barber
So I don't know if you know this, but you can actually experience this feeling here on Earth. Have you ever gone to the Tower of terror in Disneyland?

Short Wave Host
Actually, a lot. I love that ride.

Regina Barber
Awesome. So you feel weightless for a bit when it drops, right?

Wendy Lawrence
Yes.

Short Wave Host
You kind of hover in the air.

Regina Barber
Even though you're falling.

Short Wave Host
Oh, right.

What? I don't get it.

Regina Barber
In physics, we call that free fall. All the astronauts in the ISS orbiting Earth are just falling. That's why they feel weightless.

Short Wave Host
Wait, so how are they falling but still orbiting? Like, horizontal and vertical motion? I get it.

Regina Barber
Well, it all starts with projectile motion.

Here's Wendy again.

Wendy Lawrence
I think pretty much every kid has thrown a ball. Gravity pulls it eventually back down to Earth. So you. You know, that ball kind of has an arc shape as it travels.

So, in general, that's happening to my spacecraft. It literally is falling back to Earth.

Short Wave Host
I think I get it. But wait, can you explain this some more?

Regina Barber
Yes. Isaac Newton. You know the guy we've been talking about, that dude?

Short Wave Host
Yeah.

Regina Barber
He had this thought experiment that if you were to shoot a cannonball, let's say, like, horizontally, that that ball will first travel pretty flat horizontally, and then it'll start to fall in that curve path. Now, imagine that we're doing this on a very, very tall mountain, and the ball would hit the ground even farther away because it had farther to fall, and it would have been in the air longer.

Short Wave Host
The arc would have been bigger.

Regina Barber
Yeah, the arc would have been bigger longer. Now, imagine you could shoot the cannonball even faster. It would travel even farther.

Short Wave Host
I can see this in my mind. Like, the arc is just getting bigger and bigger and more stretched, right, right.

Regina Barber
So now imagine that the mountain was so high and the launch was so strong that the cannonball, when you shot it out, the curved path matched the curvature of earth so that it never falls and never hits the ground.

Short Wave Host
It's just so it never falls and never hits the ground. Like, it just keeps missing the planet.

Regina Barber
Yeah. Now you're in orbit.

Short Wave Host
No, that's all it is.

Regina Barber
Yeah. That's all it is. Projectile motion.

Short Wave Host
That is so cool, Gina, thank you for explaining this to me. There is one thing that, or I really should say thousands of things that are just not so awe inspiring about getting to the Internet national Space Station these days. And that is all the stuff that is starting to clog up low Earth orbit. You know about this, right, Gina?

Wendy Lawrence
Yep.

Short Wave Host
Yeah, we call it space junk. And looking into it for this episode, it reminded me a lot of that scene in Wall E. Do you know the one I'm talking about?

Regina Barber
I do.

Short Wave Host
I love Wall er. WAll E. Neave had to, like, cut through a cluster of satellites to get off the planet right now.

Regina Barber
You know, our, that debris isn't as close, but yeah, there is debris out there.

Short Wave Host
Yeah. Like low Earth orbit is just becoming a little bit of a junkyard for orbital debris. It's generated from these satellite collisions and stuff just breaking down and falling apart.

Wendy Lawrence
Even a fleck of paint off an old satellite can do damage because we're talking about a tremendous rate of speed to stay in orbit. Space station right now is probably also about 250 miles above the Earth's surface. It's going 5 miles a second, 8 stay in orbit, same with the orbital debris. So it doesn't have to have a high amount of mass to do a lot of damage.

Short Wave Host
So that's why the space station has to monitor for space junk all the time.

Regina Barber
Morbid.

Short Wave Host
Ja. Our astrodynamicist from earlier says space junk is an escalating environmental issue and we're on kind of a dangerous trajectory. Think about single use plastic and the danger it poses to the environment here on Earth.

Moriba Jah
But that's what we're doing in space because nothing that we launch into space is this reusable thing. Except for maybe the space station.

Short Wave Host
Yeah, the ISS. Gina, did you know it has to monitor for space junk to avoid a collision?

Regina Barber
I do. I do know that, yeah.

Short Wave Host
It's part of the gig. And when I spoke to Moriba five years ago, there were about 20,000 objects that the US Department of defense was tracking. Like satellites, rocket bodies, debris.

Most of it, 90% of it is just trash. Like it doesn't work.

Now the catalog has grown to over 45,000 objects.

Regina Barber
Wow, that's a huge jump.

Short Wave Host
Yeah. And it has to do with this trend. Okay. In the last few years, commercial entities have launched thousands of satellites. Like SpaceX alone has launched 6000 of the over 9000 working satellites to create the Internet network, Starlink and Moriba, he supports a global Internet, you know, giving people access in remote locations. But he's worried about these unforeseen costs to our environment.

Regina Barber
Okay, you're really making me think very differently about launch. Like, once stuff is up there, like, what happens to it?

Short Wave Host
This is the question for our age. I mean, there is no international treaty that, say, limits space junk or sets standards for negligence. If a country creates more.

Moribaugh wants to see space become a much more sustainable place.

Moriba Jah
Countries governments need to incentivize their industry to say, you're going to get some kind of incentive or tax cut or whatever if you design, build, and operate reusable and recyclable satellites.

Short Wave Host
And he thinks those same parties need to be held accountable for responsible disposal. But until that future comes to pass, we're going to see more launches, but also more space junk littering the sky.

Regina Barber
Well, let's not contribute to the stuff in orbit right now, and let's move on to Pluto.

Short Wave Host
I like how you think. Regina Barber. We will be back tomorrow with more regular shortwave, but you don't want to miss this series every Tuesday. Tune in to our next installment of space camp.

Regina Barber
Yeah, Tuesday, we will continue our exploration of the universe with a push deeper into space.

So m I have this clip ahead of our next spacecamp episode. Reporting on something at the edge of our solar system, I have this, like, message from one of our experts.

Vladimir Lyra
This is Vladimir Lyra, your planetary officer here on Earth. This is ground control to major taunt. You're about to pass Pluto after a long, cold journey, saying hello to Pluto and getting to know you close up and personal. Look at the other side and you see the crescent of Charon. I bet the stars look very different today.

Regina Barber
And before we head out, we want to hear from you. We want you to send us your favorite planet in a voice memo in 20 seconds or less. Say what your favorite planet is, why you love it, your name and location, and email it to shortwave.org, and we may feature your voice in an upcoming episode.

Short Wave Host
This episode was produced by Burleigh McCoy. It was edited by our showrunner Rebecca Ramirez, and fact checked by me and Gina. The audio engineer was Gilly Moon, who is not from space but is awesome.

Regina Barber
Julia Carney is our project manager. Beth Donovan is our senior director. And Colin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber.

Short Wave Host
And I'm Emily Kwong.

Regina Barber
Thank you for listening to Space Camp, a science summer series from NPR.

A space science summer series.

Short Wave Host
So many s's.

Regina Barber
Yes, the science Summer series, a special Space science Summer series from NPR.

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