Season 2 • Episode 5
The star attraction of NASA’s Mars 2020 mission is the Perseverance rover. But bolted to its underside was a stowaway: A tiny, 19-inch helicopter called Ingenuity.
She was intended to fly five times on Mars, as a wild experiment to see if anything could fly in Mars’s incredibly thin atmosphere. But as the speed, altitude, length, and usefulness of Ingenuity’s flights improved, her mission was extended indefinitely. Ingenuity is still flying, nearly a year after its original mission was to end—and now, NASA is designing a new generation of Mars helicopters, based on her unlikely success. In this episode, meet the three engineers who created Ingenuity—and kept her flying against all physical, planetary, and managerial odds.
Episode Transcript
Season 2, Episode 5: The Mars Helicopter That Would Not Die.
Intro
Theme begins.
In 2013, a splinter faction of NASA engineers had the bizarre idea to build a helicopter… and send it to Mars, attached to the belly of the Mars 2020 rover. Not everybody loved the idea.
BOB: [00:04:37] / There were more than a handful of people who would be very happy to just get this stupid distraction off the rover. You know, it was a nuisance.
TEDDY: [00:11:52] Yeah. / there were a lot of / skeptics within the engineering community at large./
Today, the skeptics have become cheerleaders. Today, NASA is designing more Mars helicopters. Bigger ones. Better ones. This may be the most amazing Cinderella story in space-engineering history.
I’m David Pogue, and this is “Unsung Science.”
First Ad
In July 2020, NASA sent a helicopter to Mars.
You’d be forgiven for having some questions about that line. First of all, NASA made a helicopter? Second of all…for Mars?
I mean, how? And why?
I mean—a helicopter’s propellers work by spinning through air, right? But how are they supposed to work on Mars, where there’s practically no air at all? There’s an atmosphere, but it’s really thin.
TEDDY: [00:09:52] / The density is 1% that of Earth’s, right? / It’s such a tiny fraction when it comes to air density.
And now you have to think, okay, the rotor blades as they’re spinning, there’s almost nothing, right? How on earth—how on Mars—could they spin fast enough to actually produce enough upwards lift force, right? It sounds impossible and it is almost impossible.
Meet Teddy Tzanetos, NASA’s Mars helicopter team lead.
TEDDY: (cont’d) / to stand any sort of chance of doing that, right, there’s kind of the three hallmarks of a Mars helicopter.
One is it’s got to be very, very light, right? / So you got to be very light.
You have to have large rotor blades. The larger you are, the more air / you can push off of against.
And you need to spin those blades very, very quickly. / we’re spinning at around 2800 revolutions per minute, right? Incredibly fast. Whereas helicopters here on Earth, they’re, you know, around 500 and higher, / but they’re hundreds of RPM. But on Mars, you need to spin that much faster /.
POGUE: [00:17:40] / So / the thin atmosphere made it harder to fly.
TEDDY: Yeah.
POGUE: But presumably the lesser gravity helped you to fly.
TEDDY: It’s a bad trade. Oh, you are correct, you are correct. But it’s a bad trade overall.
So it’s about one-third the gravity of earth, right? So all of us could jump higher. You know, we could probably stand a good chance of dunking on Mars, if we could hold our breath long enough.
But it’s a bad trade overall because of how difficult the 1% the density makes flying. /
OK, so that’s the “how.” But how about why? NASA already has a rover, and it’s already got a rocket. So what value does the chopper add?
AUNG: 13:35:09 So first, if you allow me to state the obvious, we as human beings have never flown in the atmosphere of Mars, right? So this is like the Wright brothers equivalent, right, on Mars. / this would be the very first flight.
This is Mimi Aung, who was the project manager for the helicopter. I met her in 2018, while the chopper was still under construction. I was working on a “CBS Sunday Morning” story about plans to get to Mars. the Mars race.
AUNG: 13:35:50 / there are two major– important– contributions from adding the aerial dimension. The first is forward reconnaissance. So having a helicopter go kilometers ahead of a rover and /to see / where you’re going will make tremendous contributions for rovers/.
13:36:17 And the second part is, there are parts of Mars that we simply cannot get to with rovers, or even when humans get there. For example, sides of very steep cliffs. Very steep volcanoes. You would need an aerial platform that can take you there to get close up to those targets.
So that was the original sales pitch: “If this test works, then someday, a helicopter could serve as a scout.” It could look ahead, to see if this mountain or that crater is even worth driving to, so we don’t waste our time puttering over to a dead end.
We were having this conversation at the Jet Propulsion Lab in Pasadena, California. Better known as JPL, because everything at NASA winds up with a TLA. You know—a three-letter acronym.
Anyway, JPL is NASA’s robotic-spacecraft facility. It’s also where the Mars helicopter story begins. In 2013, JPL’s director Charles Elachi saw a talk.
BOB: [00:03:37] / there was a presentation about what was then the hot new thing, about drones. And he came back to the lab and he said, like, “Hey, can we do this on Mars?”
Bob Balaram is the helicopter’s designer and chief engineer. He and a small team put together a proposal for this helicopter idea.
Very few people thought it was a good idea.
BOB: (cont’d) /at every stage of the game, you know, / we could always have been canceled at any step, right?
[00:10:16] /there are dimensions to this which are not just, / “can it fly?”
[00:08:48] / it’s not just an aircraft flying on Mars, it also happens to be a spacecraft. So everything that goes with the space business—vibration testing, / shock testing, radiation, temperature extremes/—that was/ a much bigger add-on than just the fundamental/ feasibility of, can you spin something fast enough to have it generate lift.
[00:10:16 cont’d] / Like, you don’t want to be this thing that breaks apart and, you know, damages the main rover. You don’t want to be this thing that has batteries exploding. You don’t want to be this embarrassment that goes there and fizzles.
[00:13:21] / So the scientists / hated us in the beginning.
[00:13:21 (out of order)] / They were upset because we were taking away precious time from the science campaign.
(cont’d from earlier) / I think if we had failed somewhere along the way, it would’ve been a footnote and they’d have been perfectly happy. /
But Balaram pacified the doubters by reassuring them that the project would be small and limited. The helicopter would fly five times, tops, within a period of 30 days, max.
And after five flights? End of project. NASA’s focus would fully return to the rover’s primary mission: digging up samples and looking for signs of ancient life.
BOB: [00:16:45] /… and then you guys can get on. There’s not going to be this mission creep where it’s going to be one more flight, one more flight.
So the helicopter idea got some funding and a small staff. It was classified as a “technology demo,” a NASA category meaning, “tech ideas that may one day become useful to our main missions, but for now, are just experiments.” Here’s how Teddy Tzanetos explains it:
TEDDY: [00:25:59] / We do not have mission-critical goals that we must execute, like the rover, for example, right? The Perseverance Rover, its goal is to collect samples so that the next mission /, can bring samples back to Earth. That must succeed. Ingenuity did not need to succeed.
To manage the project, Balaram teamed up with our friend Mimi Aung.
BOB: [00:56:39] / MiMi Aung is a force of nature that no programmatic, financial, political thing could withstand, right? And she was, you know, the sharp point of the spear, / that was just able to push through all the obstacles.
Mimi Aung taught me what a balancing act it is to create a Mars copter. I mean, you’re limited in its size—to what can fit underneath the rover, because that’s how the chopper was going to get to Mars.
The limited space limited the size of the propellers, to about four feet long. And that meant that this thing couldn’t be designed like a regular consumer drones, with four propellers at the corners. There just wasn’t room. The propellers would have to be stacked, one above the other. Mimi Aung walked me through the design in JPL’s kind of noisy facility.
POGUE: 13:02:16 I would imagine that it’s a very fine line you’re walking, right? I mean, you could put a bigger battery in there, but that would make it heavier– too heavy to fly. So you could make the wings smaller, but that would make it not powerful enough to fly, you know? /
AUNG: 13:02:33 You– you have nailed it. (LAUGH) This is the ultimate exercise in system engineering. /
POGUE: 13:10:08 Was there ever anyone who said, “Forget it, Mimi. We’re not– (LAUGH) we’re not gonna walk that tightrope. It’s not gonna work”?
AUNG: /11:10:38 So, yes, there were difficult moments. (LAUGH) More than moments. (LAUGHTER) /
POGUE: 13:03:47 / when you add it all up with that amount of power, that amount of weight, this amount of– of rotor span, what’s the total flight time, and flight distance, and flight altitude?
AUNG: 13:04:01 So this particular helicopter is designed now to fly up to 90 seconds. And–
POGUE: 13:04:09 Ninety seconds!? $23 million for a drone (LAUGH) that can fly 90 sec– it doesn’t sound like very much!
We’ll come back to my reaction there. Let’s just say that it was not my finest moment as a forward-thinking journalist.
AUNG: 13:05:00 / So it sounds modest, as you say, but it’s an extraordinarily important– demonstration. Look, this is the first time ever that we’re flying– in an– on another planet. Flying a helicopter on another planet outside of our own earth’s atmosphere, okay?
13:05:49 / And that– I don’t think you can put a price on that. (LAUGH) Because– ba– basically this forms the basis of the fundamental principles of flying in very thin air.
Now, this helicopter doesn’t look like a helicopter. A chopper that carries people is horizontal, with a tail.
This machine looks more like the Apollo lunar module, but with two propellers on top. It’s 19 inches tall, all vertically stacked components. At the top, there’s a rectangular solar panel; below it are the two stacked propellers. They rotate in opposite directions for the same reason that a traditional helicopter has a rotor on the tail: To prevent the torque from making the body of the helicopter spin around.
And you cannot believe how light these propellers are.
AUNG: 13:44:34 / So I want you to hold it.
POGUE: 13:44:39 Oh my gosh! It’s like a dead leaf! I mean, I’m not kidding! This thing— I could blow this thing like a Kleenex. That’s amazing. And that’s strong enough?
AUNG: 13:44:51 Yes. So–it had to be built for strength, as well as for the stiffness and the light weight. So when we talk about having to fit in a four-pound bag, it is not an exaggeration. /
These blades are not just made of carbon fiber, which already has one of the best strength-to-weight ratios known to man. It’s hollow carbon fiber. There’s foam inside to make it even lighter.
Then, below the propellers, a cube, known as the fuselage.
POGUE: 13:40:15 And so what all is in that box? So camera, electronics, batteries…?
AUNG: Uh-huh (AFFIRM). 13:40:48 / So if you open, take out the outer shell of it, you will see– circuit boards surrounding a battery pack.
And that’s an ingenious design decision. It gets bitterly cold at night on Mars. So NASA assembled the circuit boards around the battery, because a battery gives off heat. The hope was that it could keep the circuitry warm at night.
AUNG: 13:43:11 / And there are– two cameras that are on there. /It’s a side-looking– color camera to take images of the terrain—
POGUE: Uh-huh (AFFIRM).
AUNG: —But on the bottom is the black and white camera for navigation. 13:41:24 / And then we have landing gears, which are legs. Again, designed to be strong but light, and with some play, you know, for landing.
POGUE: Nice! I’ll take two. (LAUGHTER)
AUNG: Okay.
Part of what makes this chopper project so complicated, by the way, is that you can’t control its flight in real time. It takes anywhere from 20 minutes to four hours for a signal from the Earth to reach Mars, depending on the planets’ positions.
POGUE: 13:17:28 / so you can’t be like, “Watch out for that mountain!” It’s not like that.
AUNG: 13:17:32 –absolutely not. (LAUGH) No, no. 13:18:02 / Definitely not a real-time (LAUGH) control of– or joysticking of any sources possible, simply due to the distance– /between earth and Mars.
Instead, the plan was for NASA to pre-script each helicopter flight on earth, and transmit those instructions well in advance.
But, to me, the scariest aspect of building a Mars helicopter on earth must have been that it’s a one-off. It’s not based on any previous design. There isn’t a series of them that NASA could steadily improve.
And there’s no spare.
And you’re going to send this machine on a 300-million-mile journey, to a place where you’ll never be able to touch it again? No repairs, no spare parts, no shelter, no adjustments?
To make matters worse, you have to do all your testing here on earth—where the atmosphere, temperatures, solar patterns, and gravity are all different from Mars.
So you know what NASA did?
They used their space simulator.
AUNG: 00:00:51 We use the JPL 25-foot space simulator here.
It’s a massive, cylindrical, stainless-steel chamber, 25 feet across and 85 feet high. It’s got an enormous door, 15 by 25 feet, big enough to accommodate the various spacecraft prototypes that NASA has tested inside since 1961, when the thing was built.
I asked Teddy Tzenetos about it.
Here’s Teddy Tzanetos.
POGUE: [00:46:36] / how close can the chamber come to simulating Mars?
TEDDY: [00:46:53] / Pretty close. / What it provides us is the ability to suck the air out. / And you can carefully adjust the amount of air that you want to match the density or the pressure at Mars. So that takes care of one part of the equation, is the air density.
What he’s calling air, by the way, is basically carbon dioxide. CO2 is 95% of the Mars atmosphere.
TEDDY (cont’d) The second part is the temperature. / Around the perimeter, along the inside edge are all of these fins that run the entire height of the chamber. Those fins can carry inside of them liquid nitrogen to chill the chamber down, right? So that takes care of the second part of of feeling like Mars, right?
[00:48:36] / So, so the third part is / the solar actual energy that’s reaching your solar panels. This chamber has a set of large powerful bulbs outside of the chamber. / you can beam down onto your spacecraft whatever sort of energy that you want. So you could simulate doing a near, near bypass the sun. / And you can dial in that energy to match and test your solar panels, test your recharge capability.
POGUE: [00:48:35, moved from above:] But you can’t do gravity.
TEDDY: (cont’d) / you hit the nail on the head. You can’t do gravity. We don’t, we don’t have an anti-gravity system figured out. / The closest thing that we were able to think up was a gravity offload system, right? And it’s a fancy name for effectively what is a pulley with a bunch of fishing line rolled around, it attached to a motor and a torque sensor.
/ so this was at the top of the chamber. / So we brought the fishing line all the way down to the helicopter. And we had a little—we had a little eyelet and we tied a very secure and very well-reviewed knot, a series of knots.
I almost named this episode, “A Very Well-Reviewed Knot.” I mean, they’ve got this helicopter, which eventually cost 80 million dollars, hanging from a piece of fishing line! I guess you really would check that knot carefully!
TEDDY: [00:50:28] / It’s like, you have the best engineers on the planet here debating knot strategy, right, on a fishing line, right? / it sounds cliché, but the entire project was hanging on the thread of a string at some point, right? If that knot failed, the helicopter would fall, hit the ground and be destroyed.
In any case, the fishing line was designed to pull gently upward on the helicopter, continuously, always exactly enough to subtract two-thirds its weight as it flies around. Because Mars gravity is about one-third Earth gravity.
POGUE: [00:51:57] /I guess you can’t use the, the swimming pools that the astronauts use, that—
TEDDY: [00:52:01] That would have been a little tough. That would have been a little tough on the electronics. /
Now, if I learned anything from the movie “The Martian,” it’s that you have to watch out for windstorms on Mars. Just ask Matt Damon’s character.
Sound clip of “The Martian” windstorm
So JPL rigged the testing chamber to generate its own wind, too. They bought a bunch of computer fans—the ones inside PCs—about 900 of them—and arrayed them in a giant wall of 25-mile-an-hour wind.
But not because they were worried about windstorms knocking things over, like in “The Martian.”
TEDDY: [00:52:26] / I love the movie. A big fan of the movie. /But most films / about dust storms / tend to overplay it. You know, it made for a great film. But you got to keep in mind, the air density is 1%. So even if you have fast gusts, fast gusts of very thin air is not imparting a lot of momentum, right? / If you have very thin air, you’re not going to have a lot of momentum, you know, transfer when the wind hit you.
/ That just means that we’re not worried about being tipped over. Wind is a big concern when it comes to flying. / We do care about winds, you know, from a stability or controls perspective. /
By early 2020, the Mars helicopter was flying well in the test chamber—noisily, but well—
Use sound from: https://youtu.be/Pd2271JaMeg?t=21
—and it now had a name. As is its custom, NASA opened up a naming contest to American school students—and the winner was 14-year-old Vaneeza Rupani.
RUPANI: Ingenuity represents the most remarkable things that humanity is capable of.
Ingenuity is a great name, but what have we learned about NASA? That’s right. They shorten all terminology. So Ingenuity soon had a nickname: Ginny.
Another kid’s essay won naming rights to the rover—Perseverance. Wanna guess its nickname? Yup. Percy.
Finally, on July 30, 2020, everything was ready. The Mars 2020 mission lifted off. It was like a set of Russian nesting dolls: The helicopter was nestled beneath the rover, which itself was inside a landing jetpack, which was packed into a landing capsule, which was stored at the top of an Atlas 5 rocket.
Audio of takeoff… let it play under the following
Somehow, the Mars helicopter had made it past the bean counters and the skeptics, the physics problems and the political ones. One executive joked that the helicopter should have been called Perseverance!
I think that this much of the story has been pretty cool—but it’s nothing compared to what happened after Ingenuity reached Mars. Up next, the part where Ingenuity’s flying blew everyone away. The part where it got frozen to death 200 times. The part of the three miracles. The part you’ll hear after the ads.
Ad break
Last time you heard from me, the Perseverance rover was lifting off for its 7-month journey to Mars. And it had a stowaway: The first helicopter ever to leave the earth. It was bolted to the belly of the rover, on its side, protected by a cover that, once you take it off, looks kinda like a guitar case with the lid missing.
The whole package arrived at Mars going 12,000 miles an hour. How NASA got from there to setting the rover down onto the Mars surface gently, without stirring up any dust that would have gotten on its cameras, is a story in itself—and an episode of “Unsung Science” in itself, from last season.
{{{{{{{From the Mars Landing episode—a super truncated version of the landing sequence:
BEEP!
/ Parachute opens.
BEEP!
/…and the jetpack’s eight engines light up/.
F jetpack.aiff
/ The rover drops out of the jetpack on its nylon ropes. /
5 touchdown.aiff
NASA: Touchdown confirmed! Perseverance safely on the surface of Mars! Ready to begin seeking the signs of past life. (cheers)
Let the applause continue.) }}}}}}}}}}}
That was February 18, 2021. It took a month for the rover to wake up, get its bearings, and undergo testing before NASA was ready to drop Ingenuity.
The first step was kicking off the debris shield—that guitar-case thing—on March 21. Here’s integration lead Farah Alibay, giving a press conference.
Farah: / And what you’re looking at here is the debris shield on the ground. / But what’s the coolest thing is you can see ingenuity there, all tucked in below the rover, doing okay. / Everything is all in place.
The rover, with the helicopter still underneath, spent a couple of days driving to the spot that NASA had picked out for…the copter drop.
FARAH (cont’d) / And then when we get there, we’re going to go through a series of steps to get the helicopter from its current horizontal position all the way to being vertical and then being dropped on the ground. /
Finally, the bottom of the helicopter was allowed to swing down 90 degrees, into an upright position. The connecting bolt blew off with a small explosive, and Ginny dropped a couple of inches to the ground.
bolt noise
At this point, the rover drove a hundred yards away, leaving the copter alone and shivering.
Now it was time for Ingenuity’s first big test. No, not zooming off into the ruddy Mars sky. According to Teddy Tzanetos, the first big challenge—
TEDDY: [00:20:17] /…is surviving the first night, okay? Mars is so cold that the sheer problem of just, hey, keep enough heat in the system and make sure you have enough energy in your battery tanks to warm the battery overnight, right, is a huge—was a huge challenge. It still is a huge challenge.
During the day, summertime on Mars is nice—in the 60s or 70s Fahrenheit. But at night—hoo boy. We’re talking negative 130. And those temperature swings are a big problem for delicate machinery.
TEDDY: [00:22:19] / every time you thermal cycle something, heat something up and then cool it down, everything expands and then contracts, expands and contracts. And just like if you were to take a metal spoon and bend it back and forth, you do that five, ten, 30 times, eventually it’ll snap. Think of now all of the electrical joints inside of Ingenuity, expanding and contracting, expanding and contracting, right? And that, that kind of gets to the core of, of one of these big milestones, is surviving the night /.
POGUE: [00:23:14] / And we all know that, you know, electric car batteries, cell phone batteries, they all are horrible in the cold. /
TEDDY: [00:23:36] Exactly. /so what do we do, is we conserve as much as we can. / Throughout the night, we would use a little bit of the battery energy to keep that temperature at around -20. / And then once sunrise happens, then the SOC starts climbing again.
SOC—that’s the state of charge. Meaning how full the battery is.
All told, two-thirds of Ingenuity’s battery power goes to keeping the thing warm at night. Only one-third is actually used for flying!
Anyway, Ginny did survive the first night. And the first two months of nights. Finally, on April 19, it was ready to take its first flight. The plan was to spin the rotors up to over 2500 rpm, fast enough to lift the whole machine slowly, majestically, into the sky!
Well, OK—slowly, majestically 10 feet off the ground.
And there it was supposed to hover for a magnificent 39 seconds, take a couple of pictures, and then land.
The thing is, at this point, Mars was so far away from the earth that it would take any messages from the helicopter four hours to arrive!
So for four hours after the flight, the NASA team had no idea whether or not its $80 million drone had even flown. For all they knew, it was a pile of twisted metal in the dust.
First flight 1.aiff
Tim: Earlier today, the helicopter flew. As it was flying and after it landed, it transferred its data to the base station. When it shows up, our team can take that data and decode it, and see what happened during that flight.
This is how the live YouTube broadcast went from JPL, as Mimi Aung, Teddy Tzanetos, Bob Balaram, and their team waited for the news from Mars.
First flight 2.aiff (continue through the VO below)
ANN: We’re moments away from getting that all-important data, and the anticipation’s definitely building in the room.
Down: This is downlink. We are beginning to fetch the data from Mars 2020.
Flight: This is flight control. Ingenuity is reporting having performed spinup, takeoff, climb, hover, descent, landing, touchdown, and spindown. (applause) Confirmed that Ingenuity has performed its first flight of a powered aircraft on another planet!
That data was pretty cool—but not as cool as the data that showed up next: a picture.
(crowd roars)
Terr: So the image we’re looking at on the screen is/ showing us hovering above the surface of Mars. How incredible! The onboard navigation camera points straight down, so we’re seeing its shadow right now.
ANN: I can just hear Mimi in the background, “This is real! This is real!” It’s so amazing!
TERR: We’re gonna wait for the Perseverance rover image of us.
That would be… a photo taken by the rover, of the helicopter in flight.
Crowd loses its mind
It was actually a bunch of frames, kind of like a GIF—a jerky little movie of the first flight.
And that… was the first time a human-made aircraft had ever flown under its own power on a distant world.
On Flight #2, three days later, Ginny went a little higher—16 feet—and flew sideways for the first time. 7 feet out, then 7 feet back to the start. Flawless.
Flight #3: 4.5 mph, 328 feet.
Flight #4: 887 feet. This time, another first: the rover’s microphones recorded the sound of Ingenuity.
Copter sounds.aiff
Flight #5: Ingenuity flew to a new landing spot for the first time, 430 feet away.
Clearly, something spectacular was happening. There’d been a couple of little glitches, which NASA fixed with software upgrades—but otherwise, this thing was performing like a champ. Didn’t crash, didn’t fall over, survived the frigid Mars nights.
The skeptics around Bob Balaram had begun to soften.
BOB: [00:16:45] / in those five flights, we proved our merit. We proved our worth, right? And that’s when things started changing, right? And that’s when the scientists said, “Oh, this thing actually works. Oh, those images are pretty darn cool. We can actually infer some geology from them, and we can decide where to send the rover.”
One scientist, who’d publicly slammed the helicopter as a waste of time and money, actually approached Balaram at JPL.
BOB: [00:13:21] / he was man enough to just say, you know, “you guys proved me wrong.” /
Ingenuity’s mission was to fly five times and then shut up forever. Go off and crash somewhere. But suddenly, that seemed like a waste.
In fact, the scientists wondered if maybe Ingenuity could do some real scouting for the rover? They wanted to know if a region known as Seitah (SAY-ta) would be worth rovering over to. Answering that question would mean flying Ginny much faster and farther than ever before.
BOB: [00:18:14] / it was a calculated risk on my part, because my take on it was if we succeeded in that flight, that would seal the science case once and for all. And we did that. We did that long flight. / we went across the region of Seitah and we did the forward scouting for them.
[00:19:22] / once the scientists saw those images, they were completely on our side, you know, and then they started asking us to go here, go there. / [00:13:21] / We kept succeeding, so they couldn’t get rid of us!
Suddenly this little black-sheep technology demo found its classification upgraded—to an operational demo. And its 30-day lease on life was upgraded, too—now the project was extended seven months, to at least September 2021. It was going to participate in the actual mission of exploring Mars!
TEDDY: [01:01:34] / there was an area called Raised Ridges / that the rover team was potentially interested in exploring, but they weren’t quite sure. And we flew out there. We took some images and we found out, no, it wasn’t as interesting as they thought it was. That’s a win. That’s time saved from the rover. /Flight 13, we were able to fly around an outcrop called Faillefeu and generate a three—beautiful three-dimensional map that you can look up online and you can zoom around in in three dimensions/.
Little Ginny was no longer a freak, an orphan, a nuisance.
TEDDY: [01:04:51] now we’re for real, right? Now we have real mission objectives and the stakes are much higher.
For Ingenuity, it was a miracle—the first of three.
Ingenuity kept flying through the summer, getting better and doing more. On Flight 12, it flew for nearly 3 minutes—so much for that 90-second thing.
On Flight 18, it flew farther and faster than ever before: almost half a mile, at 12.3 miles an hour.
Throughout these flights, Ginny sent a steady stream of photos back to earth: Of craters, of deltas, of the parachute and other landing gear from Mars 2020 itself. The team kept improving its software with updates—for example, to allow it to fly higher, to let it change speed in mid-flight, and to understand the terrain below it better.
Now, remember: NASA had designed the helicopter to survive for only 30 sols. A sol, S-O-L, is one Mars day. See, a Mars day is about 24 and a half hours, so we can’t really use the word “day”; we’d get that confused with earth days. So the word is “sol.”
As the May sols flowed into the warmer sols of June, warmer weather just made it easier for Ingenuity to stay warm.
TEDDY: [00:31:44] We would charge during the morning and then, hey, we’d be at 100% state of charge by 1:00 in the afternoon. Great.
As the mission progressed, we went into the summer. Things got even better in the summer. We had excess energy. / We call it Leaving Energy on the panel.
But everybody knew it couldn’t last.
TEDDY: [00:25:59] no one designed for winter ops on Mars. She was designed to operate in spring and, and nowhere outside. /
In winter, the sun is lower in the sky, which means less light falling onto the solar panel …and on Mars, there’s more dust in the atmosphere in winter, which also means less sunlight hitting the panel.
TEDDY: [00:33:02] / So we’re not charging as much. And because it’s colder, we’re using more energy to stay at the same temperature, right?
/ we knew that we were going to run into a problem here where we might reach our limit. And on sol 426, we hit that limit. We went to sleep on sol 426 with about 70% state of charge in our battery. It was so cold that night. / And we were burning energy, burning energy, burning energy. / And the battery drained all the way to zero. We stopped heating ourselves. / In the Ingenuity mission on sol 427, we tried talking to her, and she didn’t reply.
So that was it. The copter was unresponsive and frozen. After a spectacular 427 Mars days and 28 flights, little Ingenuity was dead.
POGUE: [00:44:32] So did you do any, like, little micro-mourning, like, “Well, that’s it. It was a good run”? Or are you trained not to get emotionally involved?
TEDDY: [00:44:42] / There’s always that question in the back of your mind, you know, did we get to the end of the mission? / [00:36:07] /There’s a part of you that’s always emotionally prepared in the background, right, to …to call it. /OK, let’s assess. Let’s analyze, let’s find out what happened, let’s see what we can learn from it.
For three days, the team threw themselves into studying what went wrong.
TEDDY: [00:36:07] / pulling up the schematics, pulling up the designs, and trying to come up with any explanation, any reasonable explanation that we could to to explain what was happening.
You know how, in movies, there’s that trope where the hero starts frantically giving CPR to revive his best friend, who’s been shot? But the hero’s so overcome with grief that he keeps CPR-ing way too long, way past the point where everyone else realizes the buddy is dead?
Scene like that.
It was kinda like that. The comms team spent day after day frantically pinging their baby on Mars, desperately hoping for a response.
And then…on the third day…they got one.
Ingenuity responded. Somehow, it was alive—and taking commands again.
TEDDY: [00:36:07] / We wiggled our blades. We did a high speed spin just to confirm that everything was still healthy.
It was the most incredible thing—and eventually, they figured out what was happening.
Each night, Ingenuity really was freezing. The battery really was dead, so there was no longer anything to keep the electronics warm.
But each morning, the solar panel started collecting energy, and Ingenuity thawed out.
TEDDY: [00:36:07] / What was happening is that every morning it was like Groundhog Day. The sun would rise. She’d have 0% state of charge in her batteries.
But by pure luck—or pure design brilliance—Ingenuity has a little circuit that directs the first trickle of energy to the battery. Bob Balaram calls it the Lazarus circuit.
BOB: [00:21:14] / So the piece of circuitry that we call the Lazarus circuits, which divert this solar power to first warm up the battery and thaw it out, and when the battery gets to about / -13 degrees Fahrenheit, roughly, it then starts charging of the battery.
So basically there is a piece of old fashioned electronics, you know—no digital, no computer, no nothing—that brings the helicopter back from the dead every single morning.
Once the battery is warm enough, it begins to charge, and the electronics come to life.
So why hadn’t Ingenuity been responding to pings from earth? Because each night when it died of cold, its clock got reset to zero. So when NASA sent its morning commands at the usual time, the helicopter didn’t know it was time to listen!
TEDDY: [00:36:07] / And that’s what was happening, is that Ingenuity was waking up later on in the afternoon, / and / she was waiting, you know, for commands as if nothing had ever changed, right? It was just another day. Just happened to be later on in the afternoon than usual.
Once the team on Earth realized that, they tried reworking the timing of the commands.
Bob: (cont’d) We catch the helicopter at that time, talk to it, set the clock. And then during the rest of the day, where it’s still warm, we then schedule a flight for or any other activity for late in the afternoon. And it does its job, goes into the night thinking it’s going to get through the night. But, you know, / we know that around midnight or something it’s gonna die. And then it comes back to life every single morning. /
Ingenuity continued freezing to death every night…and rising from the dead in the morning…and it kept right on flying…through the entire winter. For 150 days and nights—until the weather began to warm up again.
Now, incredibly, Ingenuity is no longer freezing at night—it’s returned to its original heating and flying patterns! This chopper will…not…die!
It was Ingenuity’s second miracle.
But as promised, there is a third one. This technology demo, this dark horse, this waste of money…has a third act.
See, the primary mission of the Perseverance rover is collecting samples of dirt and rocks, and to put them into airtight tubes. But collecting the samples is only Number 1 of three missions that will get those samples back to earth.
Number 2, possibly launching in 2028, is called Mars SRL, the sample retrieval lander. That is, a spaceship that will land on the surface of Mars.
BOB: [00:44:23] / the Perseverance will trundle up to the lander, present the samples to a little robot arm on the lander, which will carefully take those tubes and stick them in a canister that will then be mounted into the Mars ascent vehicle. And then, you know, the Mars ascent vehicle eventually takes off.
And Mars mission number 3 will be a ship in Mars orbit that intercepts those samples and flies them back to earth.
But with a project this big and expensive and complicated, it’s really scary to have it all lie on the shoulders of the Perseverance rover. I mean, it’s a fantastic rover, and it’s been performing like a champ. But by 2028, it will have been driving around in the rocks and the dust for eight years, and any number of things could have gone wrong. NASA needed a backup plan for getting those sample tubes onto the lander.
And can you guess what the backup plan is? Two…more… helicopters.
BOB: (cont’) / So what’s being designed right now, is a variant of Ingenuity that has the capability to do this. /
[00:47:37] And you would have effectively a claw or an arm that would grab one tube at a time. So we are basically adding on four wheels. And a small robot arm to Ingenuity, that Ingenuity design.
And we’ll have two of those for redundancy /. They’re called sample recovery helicopters. SRH. I tend to think of them as ‘Sarah.’ It’s–the Ingenuity was Ginny. We’re going to have two ‘Sarahs’ on Mars helping.
Even the Sarahs aren’t the end of the Mars chopper line. Balaram is also working on a much bigger copter, capable of carrying ten pounds of science equipment into the air. It’s currently called the Mars Science Helicopter.
BOB: [00:41:48] / the JPL is interested in saying like, “How do we scale it up, okay? / And let’s see what such a system design might look like.” And I was leading a team that did that study and continues to do that study. / it would look effectively like a hexacopter, with effectively each of the six blades looking roughly the same size as in Ingenuity, blade diameter, okay? /
So…Three miracles.
The first miracle was that the Ingenuity helicopter, once mocked, cursed, and dismissed as a nuisance, wound up outliving its five-flight, 30-day mandate, and became an essential part of the Mars 2020 mission.
I mean, I was the idiot who said to Mimi Aung,
POGUE: 13:04:09 Ninety seconds? $23 million for a drone (LAUGH) that can fly 90 sec– it doesn’t sound like very much!
I played that recording for Bob Balaram. He was cool about it.
BOB: [00:02:57] But that’s okay. You can join the line, a long line, of people who are skeptics.
The second miracle was that Ingenuity refused to die, even when Mars froze it solid every single night for hundreds of nights.
And the third miracle is… that Ingenuity now has descendants. Two will go to Mars on the sample-retrieval project, and could wind up saving the whole three-mission, multi-multi-billion-dollar arc…and a big helicopter with six giant rotors could become a primary vehicle on a future mission.
As for Ingenuity herself… she is still flying. She’s survived two dust storms and one brutal, bitterly cold winter—and she is still flying. And still breaking her own records. On December 3, 2022, she flew 46 feet off the ground.
And nobody can see any reason why she’ll ever stop.
POGUE: [00:58:53] Is there any hard death day for Ingenuity?
TEDDY: No.
POGUE: Somewhere, some consumable that will—
TEDDY: [00:59:02] No, your guess is—and I’m very serious when I say this—your guess is as good as mine. We’re well outside of the manufacturer’s original warranty window, right? That 30 sols really was the design point.
But I’m very happy to say that our batteries are extremely healthy, / Our solar panels are doing well, our motors are still performing extremely well. / Our computer system, / is still performing just fine as it was on the first day. So there is no hard date, there is no key consumable. / But when that day does come and it will come, we’re going to have a massive party.
BOB: [00:34:00] If we had failed, no big deal, it would have been a footnote. You know, we would have been saying, “oh, yeah, they tried to fly a helicopter and it got two feet above the ground and tipped over and crashed, a ha ha,” you know. And then maybe the social media would have had a field day for a few days and then they would have gone on to the next thing.
This may be a good time to reveal the secret of Ingenuity’s ballast. A little Bob Balaram easter egg.
BOB: [00:49:24] / when we were building Ingenuity, I wanted to have some kind of token of appreciation. A talisman / paying homage to the pioneers who came before.
He learned that it was possible to buy a piece of cloth from the wing of the first airplane that ever flew on earth—the Wright Brothers’ Wright Flyer.
BOB: / Apparently, the Wright brothers were, you know, they were auctioning pieces of fabric from the first flyer to raise money. You know, fundraising never goes away in this business.
And so, so we got a piece of the fabric. / and we basically cut out a small piece. / you know, half inch by half inch kind of swatch. And that’s wrapped up in some tape and tied to a little cable bundle under the solar panel.
[00:51:37 (moved up) I had my engineers sworn to secrecy.
(cont’d) And so that same piece of fabric flew about a half a dozen times on Kitty Hawk /, so it flew five times there and it’s flown 33 times on Mars. That little piece of fabric. / there’s a lot of parallels, by the way, between what our team had to face and what the Wright brothers faced. /
Balaram and Tzaentos are still at JPL, building insanely cool rotorcraft. But in the summer of 2021, Amazon poached Mimi Aung from NASA…hired her to oversee its plan to launch a constellation of satellites—over 3 thousand of them—to provide internet service.
But Balaram believes that cool, bold projects like Ingenuity are important to NASA’s future—and to its ability to attract young engineers.
BOB: [01:00:17] / it’s a very real issue, by the way, in terms of our retention of people, in terms of what we can offer. You know, kids, people, go to Amazon or here or there and they build some gadget to deliver a brown box into your doorstep, you know, but they get paid twice as much or something, right? And—
POGUE: [01:01:05] Yeah. Yeah.
BOB: [01:01:06] How do you compete with that? /
POGUE: Well, the next time you’re interviewing someone, you can say, “Do you want to engineer something that drops off brown boxes on front porches, or do you want to deliver something to Mars, like I did?”
BOB: [01:02:52] You know, it’s—it’s—it’s true. [01:04:36] Packages to Mars versus packages to your front doorstep is still the hook. But it doesn’t mean that/ we should not be thinking about exciting, good ways of making that happen. /Hopefully we’ll learn some things from Ingenuity and take that into everything else we do.
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