Satellites are like robots in the sky: they monitor the weather, make GPS possible, and take stunning pictures of outer space! But how exactly do they work? When a satellite named Meep Moop gets delivered to Brains On HQ by mistake, Molly and co-hosts Tessa and Fallyn learn all about satellite solar panels, thrusters, and radio waves! Then, they chat with Dr. Moriba Jah about satellite space junk and the importance of keeping space pristine. Plus, a stumper of a mystery sound!

Featured expert: Dr. Moriba Jah, space environmentalist and professor of Aerospace Engineering and Engineering Mechanics at The University of Texas at Austin. Find him on Instagram at @moribajah and Facebook @Moriba Kemessia Jah

Special thanks to: Dr. David “Goldy” Goldstein, principal engineer, SpaceX; Colonel., U.S. Air Force, Ret.

Resources: If you want to hear more about GPS, check out the Brains On episode How does GPS know where you are?

And if you’re curious to learn more about space junk, check out Satellite uses giant net to practice capturing space junk and the video Tracking space junk, both written and hosted by Loren Grush and produced by The Verge.

Audio Transcript

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TESSA/FALLYN: You're listening to Brains On, where we're serious about being curious.

Brains On is supported in part by a grant from the National Science Foundation.


MOLLY BLOOM: Oh, my package is here.

DELIVERY ANDY: Hiya, Molly. Got a honker of a box for you. Just going to roll it in.



Here we go. Yeesh, Molly. What'd you order? 300 bags of cement?

MOLLY BLOOM: No. But I did order 25 insects fossilized in prehistoric amber.

DELIVERY ANDY: Yikes. Those must have been some big bugs. OK. Well, have fun with them.

SANDEN TOTTEN: Oh, hey, Molly, did Penelope's jungle gym get here?

MOLLY BLOOM: Oh, hey, Sanden. Hey, Penelope. I mean, maybe. A jungle gym would make more sense in a box this big.

SANDEN TOTTEN: Radical. Let's bust it open. Ready, set, wreck it. I got one side open.

MOLLY BLOOM: OK. Calm down. We don't want to break anything.

SANDEN TOTTEN: Now, we just got to pull it out. Come on, Molly. On three. 1, 2, 3. [GRUNTS]


Hold up. This is definitely not what I ordered. It's all metal and has solar panels on it.


MOLLY BLOOM: Sanden, it just made a sound. What is it?

MARC SANCHEZ: Hey, Molly. Hey, Sanden. Nice satellite.

MOLLY BLOOM: Wait. Marc, did you say satellite?



You're listening to Brains On from APM Studios. I'm your host, Molly Bloom. And today, I'm here with our two fabulous co-hosts, sisters Tessa and Fallyn from Hartford, Connecticut. Hi, Tessa and Fallyn.

TESSA: Hi, Molly.

FALLYN: Hey, Molly.

MOLLY BLOOM: Today, we're talking about satellites. A satellite is any kind of object in space that circles around something bigger than itself.

FALLYN: The moon is a satellite because it travels around the Earth.

TESSA: And the Earth is a satellite because it goes around the sun.

MOLLY BLOOM: But the kind of satellites we're focusing on today are human-made satellites. They're like robots in space circling the Earth doing different jobs for us humans below. Tessa and Fallyn, you sent us a question about satellites.

TESSA: Yeah. We wanted to know how they work.

MOLLY BLOOM: So what made you curious about satellites in the first place?

FALLYN: Well, we were driving in the car. I forget where we were going. But I noticed my mom's GPS and how it could detect how fast she was going on her phone. So I wanted to know how satellites were connected to that.

MOLLY BLOOM: That's a great observation. So what do you think is the coolest thing about satellites based on what you know at this point?

TESSA: Probably there's a bunch of them in space.


MOLLY BLOOM: Excellent. So if you could go to space, would you want to?

TESSA: Yeah.

FALLYN: Maybe. I'm not scared of it. It's just kind of being that far from the Earth kind of scares me. But yeah.

MOLLY BLOOM: So Tessa, what about space makes you excited about potentially visiting?

TESSA: Probably just, like, seeing all the planets.

MOLLY BLOOM: So which planets or places in space would you want to visit?

TESSA: The moon.

MOLLY BLOOM: Oh, yeah. What would you do on the moon?

TESSA: Jump around. [LAUGHS]

MOLLY BLOOM: Yes. Yeah, I know that lower gravity looks so fun to be in. Do you like going on trampolines and stuff?

TESSA: Yeah.

MOLLY BLOOM: So it'd be like the moon is trampolines but times 1,000.

TESSA: Yeah.

MOLLY BLOOM: So cool. So Tessa and Fallyn, these are great questions. And you are not the only ones with questions about satellites. We also got this question from Maxwell.

MAXWELL: My name is Maxwell, and I'm from [INAUDIBLE] in the Philippines. My question is, how does a satellite transmit data?

MOLLY BLOOM: Luckily and somewhat unexpectedly, we have a satellite with us today to help us find the answers.


MARC SANCHEZ: Oh, Meep Moop, you're really too much.

TESSA: Meep Moop?

MARC SANCHEZ: Oh, that's the satellite's name. Can't you tell?


Oh, I know. That's what I told them, Meep Moop.

MOLLY BLOOM: Anyway, you might not realize it, but satellites are very likely a part of your daily life.

FALLYN: Yeah, we know satellites make GPS possible.

TESSA: GPS stands for Global Positioning System.

MOLLY BLOOM: GPS is a tool owned and created by the United States. And it's made up of 24 satellites in the sky that can tell us where we are on Earth.

FALLYN: How to get someplace else.

TESSA: And how long it might take to get there at any given moment.

MOLLY BLOOM: We have a whole episode about how GPS works. We've linked to it in the show notes.


MARC SANCHEZ: Why, thanks, Meep Moop. Meep Moop loves that episode.

MOLLY BLOOM: Thank you, Meep Moop.

MARC SANCHEZ: Satellites are also used to track the weather. And some satellites can even take detailed photos of outer space.

TESSA: So there are lots of different kinds of satellites.

MARC SANCHEZ: Meep Moop here is a special kind of communication satellite. When it gets to space, it will be working with a group of other small satellites to help people in remote places use the internet, text, and make phone calls.

FALLYN: So useful, Meep Moop.

TESSA: Yeah. And I had no idea satellites could be so big.

FALLYN: Yeah. I'd say Meep Moop is about the size of a picnic table.

MARC SANCHEZ: And around 500 pounds.

MOLLY BLOOM: Wha, wha, wha, wha, wha? We just moved a 500-pound satellite? Dang, those powerlifting classes are finally paying off. High five, Browski.

MARC SANCHEZ: Up top, dude-arino. Anyway, some satellites are even bigger than Meep Moop. They can be as big as a pickup truck. Others can be as small as a Rubik's cube. But no matter what size they are, all satellites have to be able to deal with what it's like in space.

TESSA: Good point. I know space can be really cold.

FALLYN: But sunlight can be super hot.

MARC SANCHEZ: Right. So satellites have temperature-control systems to deal with extreme temperatures. And most of them run on energy from the sun. See these solar panels on Meep Moop?


MARC SANCHEZ: They're all folded up right now. But once Meep Moop makes it up into space, they'll unfold like the wings of a butterfly. And these shiny wings will collect energy from the sun's rays and then store it up in batteries.

TESSA: So the sun is like Meep Moop's food.

MARC SANCHEZ: Yep. And Meep Moop also has thrusters, which are like jets.

MOLLY BLOOM: Oh, yeah. Thrusters help satellites move around in space.

MARC SANCHEZ: Without thrusters, Meep Moop would be at risk of having a bad attitude.

TESSA: Um, rude. Meep Moop is literally right there, Marc.

MARC SANCHEZ: Oh, no I don't mean a bad attitude as in cheeky or bad mannered or impudent. For satellites, attitude means the direction they're pointed in. And it's important for them to have the right attitude, you know, to be pointed in the right direction so they can send and receive information like they're supposed to.


Oh, I know, buddy. You're like a beam of sunlight wrapped in a snuggle. There's not a rude bolt in your satellite body.

FALLYN: Wait. But how do satellites send and receive information?

MARC SANCHEZ: Well, you see this big disk with an antenna in the middle of it?

TESSA: Yeah. It looks like the satellite dish on our friend's house.

MARC SANCHEZ: Exactly. Satellites up in space have dishes and antennae on them just like that so they can talk to similar ones down on Earth.

FALLYN: But how do they send those messages?

MARC SANCHEZ: Good question. Radio waves. Satellites communicate using the same invisible waves that radios use to send out music and talk shows. Radio waves are amazing because they can hold a ton of information. And get this-- they travel at the speed of light, so super fast.

TESSA: Whoa. OK. So satellites can do lots of different jobs, come in all different sizes, are powered by the sun, communicate using radio waves, and sometimes need attitude adjustments.

MOLLY BLOOM: When I need an attitude adjustment, I give myself a timeout and grab my knitting needles for some therapeutic scarf making. But firing thrusters sounds pretty fun too. I should try that next time.


FALLYN: Who could that be?

DELIVERY ANDY: Hey. So sorry to bother you again, folks. It's me, the delivery guy who is here, like, 10 minutes ago? Well, I just got a call from Explains On headquarters.

TESSA: Explains On headquarters?

DELIVERY ANDY: Yeah. They manage a fleet of communication satellites. Sounds like they got your package of 25 ancient insects trapped in fossilized Amber. So I'm wondering if I might have left their package here by mistake. It was about the size of a picnic table and made a lot of "meep mooping" noises.

MOLLY BLOOM: I think you did.

DELIVERY ANDY: Oh, thank goodness. I'll get that packaged up and out of your hair.

MARC SANCHEZ: Wait. Let me say goodbye first. Meep moop, meep moop, meep meep, moop.


FALLYN: I literally have no idea what they said.

TESSA: Yeah. But it was so beautiful.

DELIVERY ANDY: Oh, man. That was really lovely. You seem to have a way with machines. I'm wondering if there's a chance you could speak to my carburetor. My delivery truck has been acting up lately. And I would love if you could have a word with it.

MARC SANCHEZ: Oh, well, as a matter of fact, I do think I might be able to help. It just so happens I'm semi-fluent in carburetor thanks to that year abroad I spent studying inside the engine of a 1988 Ford Fiesta. Show me the way, good sir. I'll help you carry Meep Moop out.

DELIVERY ANDY: OK. On three. 1, 2, 3.


500 pounds. Excuse me.


MOLLY BLOOM: I'm glad Meep Moop is going to find its way home. And here's something that's going to find its way into your ears.

FALLYN: That segue was a stretch, Molly.

MOLLY BLOOM: Yes, it was. Now get ready for the--

TESSA: Mystery sound.

MOLLY BLOOM: You guys ready?

GIRLS: Yeah.

MOLLY BLOOM: Awesome. Here it is.


What do we think? Let's start with Fallyn.

FALLYN: OK. So I think that maybe it's a car on the highway. But it's one of those big trucks that's zooming past one of the other cars.

MOLLY BLOOM: Nice. Tessa, what do you think?

TESSA: Maybe a train that's starting slow and starting to go really fast.

MOLLY BLOOM: Both very good guesses. So we're thinking transportation is involved. Something big, moving. Do you want to hear it again?



MOLLY BLOOM: Any new thoughts?

FALLYN: No. I'm sticking with my first answer.

TESSA: Maybe it could be a roller coaster going very fast, but don't know.

MOLLY BLOOM: OK. We're still thinking something is moving.


TESSA: Yeah.

MOLLY BLOOM: OK. So we will hear it again. Guess again and hear the answer after the credits. So stick around.

Hi, Brains On besties. We are working on an episode all about UFOs or Unidentified Flying Objects. They're mysterious. They're curious. But are they real? Imagine some aliens showed up at your front door and wanted to know more about planet Earth. Where would you take them? To your local library? The art museum? Maybe to your neighbor's tree house? Tessa and Fallyn, where would you take the aliens? Let's start with Tessa.

TESSA: Maybe teach them how to play sports.

MOLLY BLOOM: Ooh. Which sport?

TESSA: Soccer or basketball.

MOLLY BLOOM: Excellent. What if they didn't have the proper limbs? What if they were more like a blob? Do you think they would like to play anyway?

TESSA: Maybe.

MOLLY BLOOM: Yeah. Maybe they'd find an unconventional way to be a really good goalie or something.

TESSA: Yeah.

MOLLY BLOOM: All right. Fallyn, what about you? Where would you take the aliens?

FALLYN: Well, if Tessa was already going to space, I'd just send them with her.

MOLLY BLOOM: You'd be like, you could go back to space. Thank you so much. And if they were like, no, please, please, please, Fallyn, please take us somewhere, where would you take them?

FALLYN: I'd probably just let them in my house and just let them-- I don't know-- make themselves comfortable.

MOLLY BLOOM: Yeah. You're like, here's a couch.


MOLLY BLOOM: Here's a TV. Let me show you some things. That would be a good way to learn about a lot of different kinds of people probably. Would you try to give them snacks?

FALLYN: I'd probably-- I'd give them something but probably the food that astronauts eat.

MOLLY BLOOM: Ah, smart. Like dehydrated stuff. Yeah. That makes sense. Well, listeners, we want to hear from you. Record yourself describing where you would take a group of alien visitors and send it to us at While you're there, you can send us mystery sounds, drawings, and questions too.

TESSA: Like this one.

CHILD: My question is, what does earwax do for our ears?

MOLLY BLOOM: Again, that's

FALLYN: Keep listening.

CHILDREN: Brains On!

TESSA: You're listening to Brains On. I'm Tessa.

FALLYN: And I'm Fallyn.

MOLLY BLOOM: And I'm Molly. Today, we're talking about satellites, our little robot friends in space.

TESSA: They help humans do all sorts of cool things, like help us find our way via GPS, collect information about the weather, and take pictures of the stars and distant galaxies.

FALLYN: Since satellites have become so helpful to humans, we've sent a lot of them up into space.

MOLLY BLOOM: Over 8,000 to be exact. That's a lot of satellites. And there are more satellites being sent up into space all the time.

TESSA: In fact, one of our neighbors is getting a little worried about it.

THE MOON: Hello, it's me, your neighbor, the moon. You know, I hate to be a pest, but-- no, wait. Let me start over. Let's do one of those compliment sandwiches. Ahem. Earth, your landscaping is exquisite-- snow-capped mountains, green forests, deep blue oceans so pretty I could stare at them all day.

And I do because as your moon, I'm literally locked in orbit around you. But you know what's not aesthetically pleasing? All this space junk. Ahem. Excuse me. I generally don't lose my temper. For a long time, it was just you and me. But in the last, oh, 70 years or so, it's gotten crowded.

All these little satellites zipping around-- I can hardly see that gorgeous landscaping I referenced earlier in my previous compliment. I know. I know. They're helpful. They can send and receive messages over very long distances through the vacuum of space using radio waves. Well, la di da. I'm the moon.

I control the tides in the ocean. Sorry. Maybe I'm a little jealous. But I'm also worried. Guess what happens when these satellites stop working? They stay up here. They become space junk, literal junk in space. Guess humans didn't have enough landfills. They needed to make garbage up here too.

Space should be clean and pristine. But what do I know? I'm just a gray hunk of rock, and you're a multi-layered planet with living, breathing lifeforms and cool stuff like fire and water and various kinds of cheese.

OK. Compliment sandwich complete. Thanks for listening, Earth. You really are a great friend. Love, The Moon.

MOLLY BLOOM: Well, that was quite the moony monologue. Tessa and Fallyn, what do you think about having all these satellites orbiting Earth?

FALLYN: I'd say that it's a little weird but because they're supposed to be there, it's not as creepy.

TESSA: Yeah.

MOLLY BLOOM: One of the interesting things is that there isn't one group in charge of keeping track of all of these satellites.

FALLYN: There's no mayor of space to watch over the satellites.

TESSA: And there aren't any traffic lights or stop signs in space.

MORIBA JAH: Everybody's kind of doing whatever it is that they want. And there's no common set of rules that are being followed. And that's the risk.

MOLLY BLOOM: That's Dr. Moriba Jah. He's a professor at the University of Texas at Austin and studies how objects like satellites move in space. You can picture all of the satellites in orbit like a three-lane highway from Earth with some circling closer to Earth while others are further out. And they're all zooming super fast.

TESSA: With so many satellites in space at once, it means there's a bigger chance they'll crash.

FALLYN: Exactly. And when these satellites collide, it creates stuff called space debris or space junk.

MORIBA JAH: And so it's everything from dead satellites to pieces of solar panels that break off. Sometimes the satellites collide with each other and become smaller pieces, fragments, nuts, bolts. So everything from flecks of paint that chip off to entire satellites comprise what is space debris.

MOLLY BLOOM: And all of this space debris and junk can interfere with other satellites. It might even affect how some of them work, which can mess up communications, internet, GPS, you name it.

TESSA: Depending on where their orbiting, satellites can last up to a few years to hundreds of years in space.

MORIBA JAH: Right now every satellite is single-use. As soon as that satellite stops working, it's garbage.

FALLYN: Satellites that orbit closer to Earth do eventually get pulled back down by gravity.

TESSA: As they fall, most of their parts actually burn up in the Earth's atmosphere.

MOLLY BLOOM: Right. Because they fall super fast, the air in front of them gets squished together. And that air gets hot, hot enough to burn up the satellite. We don't know yet how all of this burning space trash might affect our environment here on Earth. In the past when humans have filled up the environment with trash, it hasn't been good. So people are working on space junk solutions.

FALLYN: Some scientists, like Dr. Jah, say designing satellites you could reuse or recycle could help.

TESSA: Or sending less satellites into the atmosphere in the first place.

MOLLY BLOOM: Meanwhile, other researchers are brainstorming ways we could use technology to help clean up space junk, from using big magnets, harpoons, or even robotic arms to help grab space junk out of orbit.

FALLYN: Since humans rely on satellites, it's our job to figure out how to keep space clean and safe.


TESSA: Satellites are special machines that circle the Earth and do specific jobs.

FALLYN: Some check the weather. Others help us navigate the planet.

MOLLY BLOOM: Satellites are solar-powered and have temperature-control systems to help them survive the extreme hot and cold of space.

TESSA: They also have little jets called thrusters to help them point in the right direction.

FALLYN: Humans have spent a lot of satellites into space, and it's becoming a problem.

TESSA: Many satellites have become space junk. But scientists are trying to figure out how to clean up that space mess.

MOLLY BLOOM: That's it for this episode of Brains On.

FALLYN: This episode was written by Rosie Dupont and Ruby Guthrie.

TESSA: We had production help from Molly Bloom, Anna Goldfield, Anna Weggel, Nico Gonzalez Wisler, Marc Sanchez, and [INAUDIBLE].

MOLLY BLOOM: Our editors are Sanden Totten and Shahla Farzan. We had engineering help from Alex Simpson and Bill Ahern with sound design by Rachel Brees. Beth Pearlman is our executive producer. The executives in charge of APM Studios are Chandra Kavati and Joanne Griffith. Special Thanks to Andy Doucette and Amy and Mike Zimmel.

TESSA: Brains On is a non-profit Public Radio program.

MOLLY BLOOM: There are lots of ways to support the show. Head to

FALLYN: While you're there, you can send us in your mystery sounds, questions, and drawings.

MOLLY BLOOM: You can also subscribe to our Smarty Pass.

TESSA: Ad-free episodes and bonus stuff just for you.

MOLLY BLOOM: OK, Fallyn, Tessa, ready to hear that mystery sound again?


MOLLY BLOOM: OK. Here it is.


OK. What do we think?

FALLYN: I still think it's some sort of really big truck on the highway but also maybe some sort of really loud fan.

TESSA: Yeah. I was thinking a fan too.

MOLLY BLOOM: OK. Should we hear the answer?


MOLLY BLOOM: All right. Here is the answer.

SOPHIA: I'm Sophia. I'm from Lexington, Kentucky. And that sound you heard was the Singing Bridge over the Kentucky River.

MOLLY BLOOM: So that's the Singing Bridge over the Kentucky River.


MOLLY BLOOM: But that's cars driving over it.

FALLYN: Oh, so we were pretty close.

MOLLY BLOOM: Yeah. You were really close. Yeah. So when cars drive over it, it makes that sound.

FALLYN: Oh, that's interesting.

MOLLY BLOOM: Yeah. So they call it the Singing Bridge.


Now it's time for the Brains Honor Roll. These are the kids who keep the show going with their questions, ideas, mystery sounds, drawings, and high fives.


We'll be back next week with a new episode all about why we laugh.

TESSA/FALLYN: Thanks for listening.

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