Aerospace Engineer Swati Mohan Plays Not My Job On 'Wait Wait... Don't Tell Me!' Swati Mohan was the Guidance and Controls Operations Lead on the NASA Mars 2020 Mission, which successfully landed the newest Mars Rover, Perseverance, on February 18.

Not My Job: We Quiz NASA's Swati Mohan On Planets Closer Than Mars

Not My Job: We Quiz NASA's Swati Mohan On Planets Closer Than Mars

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T. Wynne/NASA/JPL-Caltech
Swati Mohan
T. Wynne/NASA/JPL-Caltech

Swati Mohan was the Guidance and Controls Operations Lead on the NASA Mars 2020 Mission, which successfully landed the newest Mars Rover, Perseverance, on February 18. We've invited Mohan to play a game called "Mars is too fars." Three questions about planets here on Earth: Planet Fitness, Planet Hollywood and "Lonely Planet" travel guides.

Click the audio link above to find out how she does.


And now the game where impressive people attempt something that's not that impressive. It's called Not My Job. Let's face it, America. We haven't had a lot of wins recently. That's why it was so exciting to watch NASA and JPL successfully land the newest Mars rover, Perseverance, last week. If you watched it live, the person you saw and heard narrating the events as they happened was lead engineer Swati Mohan. And we are delighted to have her join us now.

Dr. Mohan, welcome to WAIT WAIT... DON'T TELL ME.

SWATI MOHAN: Thank you very much. I'm happy to be here.

SAGAL: I'm very happy to have you. Congratulations, first of all, on the very cool thing that you did. Were you as excited as everybody else was? Because we were all pretty excited.

MOHAN: I think I'm still in shock that it actually happened and went well. But hopefully, one day I'll be super excited and still in awe.

SAGAL: I know a few engineers. And because of their, you know, devotion to facts and measurements and calculations, they tend to be pretty confident. Is that not true? Or are you actually just as terrified of screwing up as the rest of us?

MOHAN: I would say dealing with all the facts and uncertainty makes me even more humble because there's so much we know we cannot control.

SAGAL: I mean, if all of a sudden, it breaks down, you can't, like, send out a truck to fix it.

MOHAN: Exactly. Or if there's a wind gust that, like, knocks you into a cliff - bad day.

SAGAL: Right. My understanding - oh, yeah, I guess so. Oh, well, there's $40 million. I don't know how much - how much did it cost?

MOHAN: I don't know the actual number, but I think it was in the single-digit billions.

SAGAL: Oh, sure. That's about right.

ADAM FELBER: And how long did it take?

MOHAN: I've been on the project for about eight years.

SAGAL: Eight years.

FELBER: So it would've been a really bad day if it blew into a cliff?

MOHAN: It would have been a really bad day, yes.

SAGAL: Yeah, I'm beginning to see why you might have been nervous after all.

FELBER: (Laughter).

SAGAL: Now your job, as I understand it, was specifically the system that allowed the rover to look where it was going and steer to the right landing space. Is that right, the guidance system?

MOHAN: Yes, that is correct, the guidance control.

SAGAL: Guidance - and that's new. We never had that before.

MOHAN: What was new on Perseverance was a new sensor and system called Terrain Relative Navigation that let us see with the camera the surface and determine where we were with respect to that surface. That part was new.


FELBER: Wow. I just have to ask. When my Internet in this house is a little bit slow and my son's got a little bit of lag on his video game, he loses his mind. How much lag were you dealing with? What was your ping in trying to land that thing real time on Mars?

MOHAN: So the lag was about 11 minutes and change, 11 minutes and five seconds or so. But because of that, we can't joystick it. There's no way we can joystick it. So about an hour before, we actually turned off the transmitter on Perseverance and basically said, we're not going to tell you what to do anymore, you're on your own. And from that point forward, Perseverance did everything herself. And all the information we got was 11 minutes behind. So when we actually called touchdown, Perseverance had been on the ground, you know, just...

SAGAL: Really?

MOHAN: ...Chilling out.

SAGAL: So you were the person that everybody was listening to and/or watching on landing day in what was called what we now know is the seven minutes of terror. Could you tell us exactly what that is?

MOHAN: The seven minutes of terror refers to the time it takes to get from the top of the atmosphere of Mars to the ground. It takes seven minutes to - from when the vehicle hits the atmosphere to when it gets on the ground. And because it takes between 10 and 15 minutes for light to travel between Mars and Earth, those seven minutes are terrifying to those of us in mission control because by the time you received word from Perseverance that hit the top of the atmosphere, she was already on the ground, either nice and healthy or in a big, flat crater. And you wouldn't know. You'd have to wait for that time to pass.

FELBER: It's like being the parent of a teenager.

MOHAN: (Laughter).

SAGAL: I mean, if you think about it, it doesn't matter at all because you wouldn't be able to do anything anyway if you were able to see it live. But that does make it worse, that you're sitting there and you have - it could be in a flaming wreck, and you have no idea.

DULCE SLOAN: Well, could it be a flaming car wreck, or could it just crash and then not burn?

MOHAN: Well, there's a lot of propellant onboard. So depending on the timing, you know, there could be some fireworks.

SLOAN: I have a question. Why do we keep going to Mars and bothering that planet trying to find stuff that's alive? Like, what is we doing?

MOHAN: We keep doing this to answer the fundamental question of are we alone in the universe? Is Earth the only place that has life? There's billions and billions of worlds out there, and Mars is the closest place and most realistic place that we could possibly answer that question. And that's why we keep going back. And that's why every mission builds on the next.

Perseverance relies on the knowledge we got from Curiosity. Curiosity found that Mars has water. It has all the building blocks for what we know life on Earth needs. So what Perseverance is looking for is the actual fossilized record of past life on Mars. And by sampling and preparing those samples to come back to Earth, that'll open up the possibility to do that detailed analysis where we could potentially, definitively say that, yes, Mars had life in the past, and that means that Earth was not the only planet to have created life. And that's a big thing.


MO ROCCA: I - you know, Swati, you must have imagined maybe just lying in bed at night, just imagined what that life might have looked like if it existed. Have you wondered? Have you kind of let your imagination kind of picture what it might have looked like?

SAGAL: Can you do an imitation of what you think they'd sound like?

MOHAN: Well, the sounds - we actually have a microphone now on the rover that you can listen to. And they released that first - the first clip of the sounds of Mars.

SAGAL: I was very - it was very cool to hear it. It was also a little disappointing 'cause we didn't hear any, like, cool, like Hans Zimmer music.

SLOAN: (Vocalizing)

SAGAL: Or like that, for example. It was just...

SLOAN: You want to hear, what the hell is this? Y'all, they done sent some more trash up here. I'm tired of them sending these little damn cars up to my planet.


SLOAN: You know what they be talking about. Like, do you think they're just hiding from us?

MOHAN: Maybe. But maybe if they go enough, they'll, like, actually show themselves just to get rid of us. That could be one option.

SAGAL: All right. Well, Swati Mohan, it's obviously fascinating to talk to you about this. We're all nerds in America now. But we have invited you here to play a game that this time we're calling...

BILL KURTIS: Mars Is Too Fars.

SAGAL: You're obviously interested in other planets, but what about the many planets to be found here on Earth? We're going to ask you three questions about earthly planets. Answer two out of three correctly, you'll win our prize for one of our listeners. Bill, who is Swati Mohan playing for?

KURTIS: Rebecca Lee of Minneapolis, Minn.

SAGAL: All right. Here's your first question. Planet Hollywood is, of course, the movie star-themed restaurant chain. The restaurants feature many props from famous movies, including which of these - A, an enormous pile of dinosaur dung from "Jurassic Park 2"; B, a plastic model of the meat slab that was pulverized by Sly Stallone in the film "Rocky"; or C, a genuine half-smoked doobie from Cheech & Chong's "Up In Smoke"?

MOHAN: I kind of want to go with one.

SAGAL: You want to go with the enormous pile of dinosaur dung?

MOHAN: Yeah. How many times do I get to pick up poop as an answer?

SAGAL: I don't know. How...

FELBER: In my business? (Laughter).

MOHAN: In my business, we don't get to do it very much. Mars doesn't have a lot of poop, you know? So...

SAGAL: So is that the one you're going for?

MOHAN: That is what I'm going for.

SAGAL: I'm afraid it was the slab of beef from "Rocky." Two more chances. This is not a problem. The Planet Fitness chain of gyms has the slogan, a judgment-free zone. But that turns out not to be strictly true, as one New Hampshire man found out when he tried to do what at a Planet Fitness? A, he brought in his four cats, which he called his workout buddies; B, he tried to ride his own bicycle on the treadmill; or C, he tried to work out completely naked.

MOHAN: I think I'm going to go for C. That's my wild guess.

SAGAL: No, you're right. That's what happened.


SAGAL: Even worse, he was doing yoga. And, yes, he did say - as he was being dragged out, he said, I thought this was a judgment-free zone.


SAGAL: All right. Now this is OK. You still have one to go. And if you get this right, you win. Here we go. The Lonely Planet is a go-to guide for exploring life here on Earth. And it points tourists in one of its books to such hard-to-find earthly wonders as which of these - a particular rooftop in Ankara, Turkey, which if you stand on it and look down, the building next door looks just like a butt; B, a Starbucks in Shaker Heights, Ohio, which they say has the best coffee of all the Starbucks in all the world; or C, a public toilet in Hull, England, which they list as one of the 500 most interesting places to visit in the United Kingdom?

MOHAN: Oh, this is hard. OK, we'll go with three.

SAGAL: You're going to go with - for C, the public toilet in Hull, England. You're right.


SAGAL: That's the answer.



SAGAL: It is apparently an architecturally and historically significant public facility.

Bill, how did Swati do on our quiz?

KURTIS: With two out of three, Swati landed successfully.



MOHAN: My husband will be very proud of me.

SAGAL: Dr. Swati Mohan was the guidance and controls operation lead on the NASA Mars 2020 mission, also known as Perseverance rover. Dr. Mohan, thank you so much for joining us on WAIT WAIT... DON'T TELL ME. And congratulations, again. You made us all proud.

MOHAN: Thank you for having me.

SAGAL: Thank you.


DAVID BOWIE: (Singing) Is there life on Mars?

SAGAL: In just a minute, L-I-M-E-R-I-C-K-S. Call 1-888-WAIT-WAIT to join us on air. We'll be back in a minute with more of WAIT WAIT... DON'T TELL ME from NPR.

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