Narrator: What would it take to hold a piece of the planet Mars in your hand?
Narrator: Going to Mars is difficult and dangerous, and humans have never made the journey – although many dream of being the first to wander the vast deserts of this alien world.
Mars has already come to Earth, in the form of meteorites that traveled the millions of miles of space between Earth and Mars. We can tell these space rocks originally came from Mars because of their mineralogy, and some even contain tiny pockets of gas that match the Martian air. These rocks were excavated through an explosive event, when a large meteorite slammed into Mars and carved out an impact crater.
sound effect: meteorite hits Mars
Narrator: Some of the debris thrown outward by this cosmic bomb escaped the planet’s gravity, and wandered the solar system for millions of years until eventually, randomly, colliding with our planet, enduring a fiery entry through our atmosphere before falling to Earth.
(1:07) sound effect: meteorite falls to Earth
Narrator: These pummeled pieces of Mars have been much changed by their travels, and only the toughest rocks survive the trip.
Since the 1970s, plans to gather a collection of different rocks on Mars and bring them to Earth in a more careful, deliberate way – known as “Mars Sample Return” – have been developed by the U.S. and other space-faring nations, only to be canceled due to the costs and complexity of such an effort.
Over the same time period, NASA used orbiting spacecraft, landers, and eventually rovers to explore Mars, revealing new insights well beyond what can be gleaned from meteorites or by studying the planet from afar with telescopes. But as good as these close-up views have been, instruments sent on space missions are limited in size, weight, and capability compared to laboratories on Earth.
NASA’s latest Mars rover – the Mars 2020 mission’s Perseverance – is a step toward finally realizing the Mars Sample Return goal of the past fifty years. Here’s deputy project scientist of the mission, Katie Stack Morgan.
(2:24) Katie Stack Morgan: Perseverance's job in that effort is to collect the rock and soil samples and to seal them up and keep them safely on the surface of Mars. Perseverance is not responsible for bringing those samples back to Earth; the rover's job is to collect them.
And we're really hoping that the samples that come back to Earth at some point in the future, if that happens, give us the best chance of answering the question, “Was there once ancient life on Mars?” And so, we are selecting our samples and looking for the kinds of rocks that will give us the best chance of accomplishing that goal and answering that very important question.
Narrator: The Mars 2020 mission is especially targeting often-fragile sedimentary layers, like those laid down in lakes and river deltas, where, on Earth, life is abundant and signs of ancient life tend to be well-preserved.
(3:16) As mission scientists use Perseverance to capture bits of rock that are artifacts of a bygone era, when Mars was more Earth-like billions of years ago, NASA is still working on plans to retrieve all these preserved moments in time, and hopes to bring them to Earth in the next decade. And so, the rover’s rock gathering is an exercise in optimism. In a nod to that, the test rover used on Earth to troubleshoot problems Perseverance may encounter on Mars is named “OPTIMISM.” Thanks to NASA’s love of acronyms, in this case “optimism” also stands for “Operational Perseverance Twin for Integration of Mechanisms and Instruments Sent to Mars.”
The qualities of perseverance and optimism were much needed in the run-up to the launch of the Mars 2020 mission. When the rover and space capsule were being put together in the cleanroom that keeps it free of Earthly microbes, a virus was about to make a big impact on our world.
(4:20) NBC news reporter Tom Costello: With health officials urging the public to practice social distancing to slow down the outbreak, communities around the country now taking action.
Katie Stack Morgan: We had just a lot of concern once the COVID situation came into being about whether we would make our launch date. And I think we're so fortunate, because if we had been in the situation maybe one or two months earlier, I'm not sure we would have made it to the launch pad. As it was, only a couple of things needed to happen before the rover was ready to go. And so, we were able to have a skeleton crew of team members come in and do that work.
Narrator: One of the members of this Mars 2020 COVID crew was the deputy mechanical chief engineer for the mission, Mohamed Abid. While most people were working from home, he helped put the finishing touches on the spacecraft at the Jet Propulsion Laboratory in Southern California, and then prep it for launch at the Kennedy Space Center in Florida.
Mo Abid: We have all this hardware that we need to assemble and launch, so everybody's trying to figure it out, and seeing how can we protect the team, while at the same time getting the right people on site. So I had to travel a few times, but because of the travel restriction that we have, we cannot take commercial airlines. So we used the NASA Gulfstream, the G3, to shuttle critical personnel.
Mo Abid: And so, that was really cool to go into this VIP… you know, it only happens in the movies, right? We’re going down to the hangar, getting into this small airplane with everybody in their own big chair, and then going for a five-hour flight, and then landing! Landing on the space shuttle runway. I think that was really awesome (laughs). I felt important for a few minutes, you know?
sound effect: jet landing on runway
Mo Abid: So, while it's really sad what's going on with all the COVID deaths and whatnot that's going on throughout the world, and we're all taking our precautions, at the same time, we're trying to get to the finish line, and time is ticking. We absolutely have to launch in this small window or we’re gonna wait for another couple more years.
Narrator: If the mission missed its one-month launch window in the summer of 2020, it would mean waiting another 26 months to try again, due to the way the planets orbit the Sun. In addition to slowdowns caused by the pandemic, technical glitches at the launch pad created more delays.
Narrator: As the Atlas V rocket that would blast Perseverance off Earth was being assembled, the crane that hoists the heavy rocket parts into place experienced a fault that took several days to fix. The launch date slipped again because of concerns over potential contamination of a ground support line, and then a misbehaving liquid oxygen sensor line pushed the launch day back even more.
Launch Control: Status Check. Go Atlas. Go Centaur. Go Mars 2020.
Narrator: The mission’s launch on July 30, 2020 overcame all the forces attempting to hold it back, including gravity. The Perseverance rover, tucked inside its capsule at the top of the rocket, was sporting a small COVID plaque featuring the Greek symbol of healing – a snake wrapped around a rod. This plaque added a space-age twist to the ancient symbol, depicting planet Earth atop the rod, and a little spacecraft circling our planet and heading to Mars.
(7:44) Katie Stack Morgan: It was a great tribute. And in some ways, great timing, I think, for the mission's successful launch and landing in a time when people were really looking for something to be excited about, and looking for a success. We had so many people pulling for us, and maybe even more than we normally would have because of the circumstances.
Narrator: Mere weeks before COVID-19 changed the world, Alex Mather, a 13-year-old from Virginia, won NASA’s student contest to name the rover. While his words seem to eerily predict the pandemic, they reflect on how many challenges always have to be overcome to make space exploration possible.
(8:27) Alex Mather: We as humans evolved as creatures who could learn to adapt to any situation, no matter how harsh. We are a species of explorers, and we will meet many setbacks on the way to Mars. However, we can persevere. We, not as a nation, but as humans, will not give up. The human race will always persevere into the future.
Narrator: Welcome to “On a Mission,” a podcast of NASA’s Jet Propulsion Laboratory. I’m Leslie Mullen, and in this fourth season of the podcast, we’re following in the tracks of rovers on Mars. This is episode six: The Promise of Perseverance.
Narrator: The Perseverance rover was modeled after the Curiosity rover, which landed on Mars in 2012, and over the past decade has found evidence the planet once had long-standing bodies of water and an environment ripe for life as we know it. Because Curiosity has a different goal than Perseverance, some instruments are different, but you’d have a hard time telling the two rovers apart.
Mo Abid: When you look far away, Perseverance and Curiosity look virtually the same, a similar shape, even color, right? But as you get closer and closer, you'll notice a lot of interesting differences. And then once you open the hood, if you will, now you’re seeing other hardware going on. You’ve got all these tubes, you know, we’ve got 43 tubes, like, what is that for?
(10:34) Narrator: Although Perseverance is storing Mars samples in tubes, rather than breaking samples down to examine them like Curiosity does, Perseverance still needs to figure out which rocks are worth taking. So Perseverance includes some of Curiosity’s instruments, like a laser in its head that zaps rocks to figure out what they’re made of, as well as new tools of analysis, like a spectrometer called SHERLOC with a sidekick camera WATSON.
Perseverance’s power source, a radioisotope thermoelectric generator, or RTG, originally had been built as a backup part for Curiosity. The wheels on Perseverance were reconfigured after Curiosity’s aluminum wheels developed holes and tears from driving over sharp rocks. Perseverance’s wheels are thicker and taller, with closely-spaced traction cleats that provide extra defense against the rugged terrain.
Like Curiosity, Perseverance has a drill at the end of a hefty arm, along with other instruments held in a block-like fist called a turret. Perseverance’s rotary percussive drill not only burrows into rock to collect a core, it has a bit with teeth that can gnaw away at a rock’s surface to do a first check on whether the inside of a rock differs from its outside. Perseverance also blows puffs of nitrogen gas to clear off debris that accumulates from abrading or drilling rocks.
(11:47) sound effects: drill, rock abrasion, puffs of gas
Narrator: These extra abilities make Perseverance’s arm and turret heavier than Curiosity’s, and overall, Perseverance weighs 277 pounds, or 126 kilograms more than the nearly-one-ton Curiosity.
(12:25) Mo Abid: Now when you talk about a heavier rover, when you change something, there's always a chain reaction. It's not, “add a few pounds here and there, therefore, everything will be the same.” No. You want to tune it really to the ounce level. When you build stuff on Earth, two, three, four kilos higher, eh, who cares? You know, what is a couple of kilos between friends, right? To launch stuff to space, every single ounce counts.
Narrator: After every ounce is negotiated and the rover is carefully put together, everything is tested to make sure it works and can take the stress of spaceflight.
Mo Abid: One of my favorite things that happens in a day [is] when someone tells me, “Hey, Mo, we have an issue – got a problem here that we need to understand or resolve.” My general reaction will be, “This is really great. Now we are going to learn something new today.” So, it's something that I live for.
And fortunately, we find surprises. If there's no surprises in testing, that means we're doing something wrong. The testing is super well, everything is going swimmingly, I get really nervous (laughs). So like, “Nothing? Are you guys sure? What are we missing here?” Because the minute you leave the launchpad, we're done. You got what you got.
(13:32) Yes, we’ve got operational work-arounds. We can do a lot of crazy stuff, as you’ve seen [with] prior rovers, you know, they failed different hardware, there's always a lot of creativity going on with the team on how can we make something work. But at the end of the day, you want to fail on Earth. You don't want to fail on Mars, right? On Earth, we can always recover. We can always figure out how to fix it. So if you fail, that's actually succeeding.
Narrator: One Mars 2020 test “succeeded” by showing a dangerous weak point in the space capsule that would carry the rover from Earth to Mars.
Mo Abid: There's one phone call that I'll never forget. It’s a call I got from my colleague from Lockheed Martin. He said, “When we lifted the heat shield from the testing stand, we found a crack along the whole circumference of the heat shield.”
Mo Abid: Now, the heat shield is a big deal. I mean, this is basically what protects Percy (Perseverance) from cooking, frying, as we enter Mars atmosphere. The temperature on the outside can go as high as 1300 degrees Celsius. That's almost the melting point of stainless steel, which is about 14, 1500. But at the same time, Percy inside is enjoying like a normal South California beach temperature day, you know, 20, 30 degrees Celsius. So that's a lot to ask from a heat shield.
When we enter the Mars atmosphere, we come in at really high speed – 20,000 kilometers per hour – about four times the speed of a bullet.
sound effect: speeding through the atmosphere
Mo Abid: And even though Mars has a really thin atmosphere, it has sufficient density that it will decelerate the vehicle. As it decelerates, it pushes the heat shield against the back shell, and so you get dynamic pressure.
(15:08) sound effect: atmospheric friction
Mo Abid: And that's not for too long, really, for a few seconds, but it's sufficient to generate high loads, about 12, 13 Gs or so. There's really different ways of mimicking those loads on the heat shield. So you can take the heat shield and you put it on a flat table. And then you pull pressure from the inside of the heat shield. So now the atmospheric air acts like your load. Or the other way we can do it is that you constrain it to one side, and the other side you put like an inflatable mattress, if you will. And as you inflate it, it pushes on the heat shield. It mimics entry loads.
sound: heat shield test
Mo Abid: So as we were running the test, we were hearing some noise, you know, cracks. You would expect something like that during this test.
sound: heat shield test
Mo Abid: So, we finished the test campaign, but one thing left was we needed to do visual inspection to make sure that nothing had broken, and we need to remove this air bag that we’d inflated to get the loads. So the team [at] Lockheed, they were removing the heat shield from this bag, and then when they lift it, they saw this crack throughout the circumference.
(16:28) sound effect: heat shield crack
Mo Abid: So it was a huge deal. This can delay launches. And it was one of the most puzzling problems we've seen. We could not find one single root cause. So typically, when there are anomalies, you like to find that one thing, you know, it's like, “Yes, that's exactly what happened. That's your fault, you little bolt.” Or whatever it is, “Your fault.” But for this one, man, it was all over the place, it’s like, “Oh yeah, maybe this, maybe that.” But we couldn't find the one smoking gun, and we're racing against the clock. We need to make it to the launch date.
Narrator: The team built a new heat shield that addressed suspected causes of the crack, tweaking things like how fast they’d cured the composite materials, and adjusting densities throughout the honeycomb structure of the heat shield’s core. Fortunately, their next-generation heat shield passed all the tests.
The cracked heat shield had been déjà vu for Mo, who’d been a part of NASA’s space shuttle program when damaged heat tiles on the shuttle’s wing led to the tragic loss of seven astronauts.
(17:35) NBC news reporter: The Space Shuttle Columbia had been scheduled to land in Florida at the Kennedy Space Center at 9:16 a.m. East Coast time, so it has now been almost two hours since they lost contact. Almost immediately, there were reports of explosions…
Mo Abid: It was the straight flashback. When we broke the shield, obviously it's load issues, it's the way we tested this, all of that, but still the intent, the use of it is really a thermal protection scheme. But definitely I had that flashback about what happened back then.
NASA Administrator Sean O’Keefe: This is indeed a tragic day for the NASA family, for the families of the astronauts who flew on STS-107, and likewise, tragic for the nation.
Narrator: Mo’s emotional connection to the space shuttle began when he was young.
Mo Abid: I was always fascinated by the space shuttle program and just by the space shuttle itself. I think the space shuttle, it's one of the most beautiful birds ever created by mankind. The astronaut suiting up and driving down to the launch pad – that was always really exciting to watch. And then you've got the countdown. Can you believe counting from ten to zero is so exciting for people?
Launch Control: Go for main engine start, T-minus 10, nine, eight, seven….
Mo Abid: I mean, I'm counting from 10 to zero. (laughs) Yeah! So thrilling! And yet, you’re always waiting for that, “liftoff!”
(19:07) Launch Control: … two, one, zero, and liftoff!
Mo Abid: The whole liftoff, the solid rocket booster separations, the whole sequence of events of going all the way up to peaceful space. It was something to be really, really thrilled about watching.
I grew up in Tunisia, in Sfax, and back in the ‘80s, late ‘70s, a space program, it wasn't really part of the national interest. You need resources. It's not cheap, space, right? And so, like many other countries, Tunisia had different priorities. Space is not one of them. There are other issues to work out for the country. So it was always something exciting to watch, and that was it.
Launch Control: …and liftoff, liftoff of the 25th space shuttle mission, and it has cleared the tower.
Houston, ground control.
Roger roll Challenger.
(20:01) Mo Abid: So, I was watching another space shuttle launch, and I remember this day very, very well. That’s when we had the Space Shuttle Challenger accident.
Launch Control: Challenger, go for throttle up.
Eyewitness news ABC7 NY reporter: Less than two minutes after liftoff, the rocket speeding the shuttle at 2,000 miles an hour exploded. On the ground, spectators not certain of what they saw. And the understated explanation from NASA:
Launch Control: Obviously, a major malfunction.
Mo Abid: The disaster rocked the whole world, you know, it was a huge tragedy. It's one of those that shows how space is really difficult. But it really got me thinking. I was like, “This is something important for us, as humans.”
And so, I start brewing and basically became determined to join, in one way or another, I need to find my way to be part of the NASA family. I wanted to be part of this team that make crazy stuff happen, like the shuttle at the time, and others. And then, prepare for issues that basically wouldn't allow the space shuttle incident like happen.
(21:08) So that was really the spark or the trigger. Now, the interaction with friends and teachers was always was like, “You're dreaming. You're never going to make it.” And some family members are like, “Eh, forget about it. No way. Stay where you are. Become a medical doctor.” So it was virtually impossible, the way it had been portrayed to me.
And when you say something’s impossible to do, that now becomes my determination. (laughs) “No, you can't go there.” Well, now I want to go there, just because you told me not to. So that was really huge motivation. One of my best favorite quotes says, “It costs nothing to dream, but everything not to.”
Narrator: In pursuit of his dream, Mo went to college in France, and then on to the University of Southern California in Los Angeles to earn his PhD. When he came to the U.S. for his studies in aerospace and mechanical engineering, he also worked on his English, with a little help from American television.
(22:05) Mo Abid: In Tunisia, English is kind of a third language, eventually, if you want to take it. I mean, French is our second language because of the French colony. So I took a class or two of English. It was more, you know, “What's this? What's that?” Nothing really spectacular. And I was really, really, really bad at it.
So coming to the U.S., I've got a very basic notion of English. But in any language, I found that there are a few key words you need to learn. I'm not going to talk about the bad words, the swear words, which everybody seems to learn those. Let's ignore those for a second. When you talk about English, the word “stuff” and the word “cool” and the word “thing,” are really, really important words. “Give me that stuff.” Now, I was watching Beavis and Butthead and… (laughs)
Butthead: Whoa! That was cool!
Mo Abid: So at the time when I came in, it was popular, and I mean, you can have a whole conversation with “cool” and “stuff,” you know? Especially in L.A., right? “Oh, that's cool.” “Yeah, cool stuff.”
(23:01) Butthead: Hey Beavis, we’re the last people on Earth.
Beavis: Whoa, really?
Butthead: We can go anywhere and do anything.
Beavis: Yeah! Yeah, anything!
Butthead: There’s no one to tell us what not to do.
Beavis: Yeah, there’s nobody to say, “Don’t burn that, no, no, no. Don’t set that on fire, no.”
Narrator: Mo set fires in his PhD studies to study combustion, and that led him to the once-seemingly impossible dream of working with NASA’s space shuttle program.
sound effect: fire ignition and crackle
Mo Abid: At USC, my thesis advisor Paul Ronney was very interested about weak flames, how they burn in microgravity, how fire takes place in the space station. So in order to understand that in space, we needed a ride. And so, a lot of testing in microgravity, working on the Vomit Comet for many, many flights to simulate a weightless environment.
Narrator: The affectionately nicknamed “Vomit Comet” was a NASA plane that would rise and fall in steep, roller-coaster like maneuvers called “parabolas” to create about 25 seconds of weightlessness. Each flight would perform 40 to 60 parabolas.
(24:04) sound effect: parabolic flight
Mo Abid: And this is leading to the first space shuttle mission, the STS-83 that launched back in ’97. But there was an issue with that shuttle, with the fuel cell. And so, they had to turn around after four days of the mission, land it, change the fuel cells, and then launch again with the follow-up one, STS-94.
You know, that was really an exciting time, unfortunately ended up with a tragedy, the Space Shuttle Columbia, the STS-107, that I was working on as well. And unfortunately lost dear colleagues that I worked with and sacrificed their life to space. I think what it was is a continuous reminder that we're taking a risk all the time. Space is not easy.
Narrator: Soon after the loss of Space Shuttle Columbia, Mo came to JPL and worked on Earth satellite missions. He eventually became manager of JPL’s Mechatronics group, which helps design, test and build all kinds of spacecraft, including his first Mars rover, Perseverance.
(25:12) Perseverance not only had to be strong enough to survive one of the riskiest parts of every space mission – the rocket launch off Earth – but also make it through the fast-paced peril of landing on Mars, and then live in a hostile alien environment where already-frigid temperatures plummet once the Sun goes down.
Mo Abid: The temperature on Mars changes drastically between night and day, so it can go from, five, 10, 20 degrees Celsius, to minus 90 degrees, minus 100 degrees. Those are huge temperature swings. And so, hardware behaves very differently at low temperature. When you have something that deploys, if you don't have the right things, you actually might freeze. You might not be even able to deploy because it's locked.
So you want to make sure that you design into the system ways that you can handle that cold. You want to have the right, for instance, lubricant – you cannot just use any random stuff. You want to make sure that you have heaters to warm it up to get it to a temperature that it can operate. But there are challenges with that because power is limited on the rover. We get, what, about 100 watts to play with? So you can’t just have your heaters all over the place, and turn them on, turn them off. You need to do all of that methodically. Every watt counts.
(26:28) Narrator: All of NASA’s rovers have landed near the Mars equator partly because temperature variations there are less extreme than farther north or south. Perseverance would be heading for Jezero, a 28-mile- or 45-kilometer-wide crater just north of the Mars equator.
The safest places to land on Mars are low, flat areas, free of deep caverns, mountains, or large rocks. But Jezero has more hazards than the standard Mars landing site. Katie Stack Morgan explains why the mission was willing to risk landing in a more difficult spot.
Katie Stack Morgan: Jezero has one of the best-preserved delta deposits of any proposed ancient crater lake basin on the surface of Mars. We have beautiful exposures of classic sedimentary structures and textures that you really only see in watery environments, where you have sediment being deposited into a lake. And also, very interesting astrobiologically-relevant minerals that we've detected from orbit, including clays and carbonate minerals – in particular, carbonate minerals around the inner margin of the crater, exactly where you might expect a shallow lake to once have been.
(27:47) Also in Jezero, we have conclusive evidence that there was a lake in the crater for a substantial amount of time, because we have an inlet valley and an outlet valley. And most crater lake basins on Mars have an inlet valley but don't have an outlet valley. So there's always a question of, “Well, how long was the water really there, and how much of the crater was really filled when there was water present?” But here in Jezero, we know for sure that that crater filled up with water and then drained out.
But that's actually another thing that makes this landing site so attractive, is the thought that, “Well, maybe here in the crater we have sedimentary rocks, and that we also might have igneous rocks,” volcanic rocks which are really great for getting absolute age dates from, which can help us can constrain the time and duration of when liquid water was present when Mars was perhaps a habitable planet.
(28:40) This area of Mars has been of interest to Mars scientists for a long time. It’s some of the most ancient crust of Mars. Jezero Crater is perched on the inner rim of one of the most giant impact basins on the surface of Mars, the Isidis impact basin. And so, there was interest in really seeing into the past history of Mars going back, could be up to 4 billion years ago or more. Jezero Crater has punched through this most ancient crust, offering us a window into that period of time in Martian history, while also giving us the kind of surface habitable environments represented by the lake and delta.
So, it seemed like a lot of things were just coming together around Jezero Crater, and made us so excited about Jezero as the landing site for Perseverance.
Narrator: Katie was familiar with Mars exploration as a member of the Curiosity rover science team, but as the day approached to send Perseverance to Jezero Crater, she was more keenly aware of the uncertainties of this mission.
(29:43) Katie Stack Morgan: This is my first experience really seeing a mission in the development phase. I joined the Curiosity team only a couple of months before it landed, when the rover was on its way to Mars and the instruments were built. And when Curiosity landed and we started to use its science instruments, and the science instruments worked, I remember looking around the room and seeing some of the other science team members who were just in such awe that the instruments were performing as expected (laughs) and that they were working! But I didn't have the experience to really understand why that was such an accomplishment.
And I think with Perseverance, I witnessed some of the struggles experienced during the development phase. Essentially, you're taking instrumentation that has never been miniaturized the way that we need to, to put it on a rover, and has never been made as hardy as it needs to be to go on a rover and survive launch and cruise and landing. And so, we're really at the cutting edge of instrumentation for many of the rover’s instruments. And there were times during development when, you know, you're on revision E and F of an instrument, and you're wondering how it's ever going to come together. And so, I now feel that awe, knowing what went into the instruments beforehand.
(31:00) Mars 2020 Launch Control: …six, five, four, engine ignition, two, one, zero. And liftoff, as the countdown to Mars continues, the Perseverance of humanity launching the next generation of robotic explorers to the Red Planet.
Narrator: After the Mars 2020 mission launched from Earth, it took seven months to reach Mars. Perseverance would use the same landing system that Curiosity had debuted a decade earlier, but upgraded to include a new hazard avoidance technology, called Terrain Relative Navigation, that would pick a safe spot in Jezero Crater.
JPL chief engineer Rob Manning, who has worked on all five of NASA’s Mars rovers, provided commentary on landing day.
Rob Manning: There’s 79 pyrotechnic devices; each have to work perfectly. One critical wire short, or one key mechanism that doesn’t work or breaks, and it’s mission over. And it’s very easy – we’re human beings, we’re not perfect. Mistakes can be made. We count on each other to find our own mistakes, and we work very hard to learn from mistakes of the past. We’ve had many failures, have to remind people that around half of the missions to Mars over history have failed, and so that could happen today too...
(32:22) Narrator: Katie felt the tension of landing day much more than what she’d experienced with Curiosity.
Katie Stack Morgan: On Curiosity, I was a happy-go-lucky graduate student. I didn't have that kind of, yet, personal or career investment in Curiosity when it landed. And so, was I anxious? Yes, but I was more just excited. And I honestly didn't really envision that there was any other option but for Curiosity to land safely. (laughs) And so, when it did, I said, “Woo-hoo, great, let's get down to business.”
But it was very different for me with Perseverance, especially given my role on the mission. My career is now tied to the success of this mission.
Rob Manning: It’s getting exciting. I have to admit I am quite anxious, but very hopeful that this machine is going to do what we asked it to.
Mission Control: We are seeing the heartbeat tones.
Rob Manning: Ok, that means there’s no more ones and zeros coming, it’s just the vehicle telling us it’s still alive.
Mission Control, Swati Mohan: We’re continuing to receive tones from Perseverance, standing by for cruise stage separation.
Narrator: Cruise stage is the part of the spacecraft that keeps the rover on the right path during its journey between Earth and Mars, and provides power and communication during the trip. Right before the spacecraft enters the Mars atmosphere, the cruise stage is released.
Rob Manning: We’re not far away. This is gonna go very quickly from here on out.
Narrator: As the spacecraft bullets through the upper atmosphere, its heat shield is put to the test against the blaze of atmospheric friction. This resistance cuts the spacecraft’s speed down enough to deploy the next braking mechanism: the parachute.
(34:03) Rob Manning: Yes! Yes! Yes! (applause)
Mission Control, Swati Mohan: Navigation has confirmed that the parachute has deployed, and we’re seeing significant deceleration in the velocity...
Narrator: The next step is to drop the heat shield so the radar can see how far down the ground is. Then Terrain Relative Navigation starts comparing what it sees below to its onboard Mars map to pick a safe spot on the surface.
Mission Control, Swati Mohan: We have completed our Terrain Relative Navigation, current speed is about 30 meters per second, altitude of about 300 meters off the surface of Mars.
Narrator: Because the Martian atmosphere is so thin, the parachute can’t slow the rover down enough to land safely, so as the altitude steadily decreases the parachute is let go, and the rover’s descent stage – a jetpack of retrorockets – kicks on. The rover flies its jetpack down to hover just above the surface, and then cables lower the rover down from the jetpack in a procedure called the “sky crane.”
(35:08) Mission Control, Swati Mohan: Sky crane maneuver has started. About 20 meters off the surface.
Narrator: After the sky crane lowers the rover down so its wheels are resting on the surface of Mars, the cables are cut and the jetpack flies off into the distance so that it can’t damage the rover.
Mission Control, Swati Mohan: Touchdown confirmed! Perseverance is safely on the surface of Mars, ready to begin seeking the signs of past life. (applause)
Katie Stack Morgan: I don't even think I realized how much anxiety I was carrying going into the Perseverance landing. But as soon as we heard that Perseverance had landed safely, I actually just burst into tears because it was so much pressure released from me and realizing, “Okay, I have a job still!”
(36:00) Rob Manning: We got it. We’re there.
Mission Control: Touchdown confirmed, we’re going to wait for the images.
Rob Manning: This is so exciting. The team is beside themselves. It’s so surreal. Stay tuned, we might get some pictures…
Narrator: The landing of Perseverance rover on February 18, 2021 seemed even more surreal once we got video of the entry, descent and landing procedure known as “EDL.” Before, we could only imagine the spacecraft going through every pre-programmed step, but after Perseverance landed, it sent video recorded from multiple cameras: one of the rover being lowered down from its sky crane jetpack; one looking down to the surface of Mars as the retrorockets swirled the reddish-brown dust below; one looking up at the parachute as it popped open, revealing that it had, encoded in its fabric, JPL’s motto, “Dare Mighty Things.”
Dave Gruel, who has worked on all five of NASA’s Mars rovers, and for Mars 2020 was manager of the assembly, test, and launch operations, also led the team that added the EDL cameras.
(37:11) Dave Gruel: So we added on six cameras and a little processor box that would store all the data the cameras took. And then the question got asked, “Well, is there a way to include a microphone as part of the EDL camera system?” And it just so turns out that the processor had multiple ports in it to plug an off-the-shelf microphone into.
The biggest challenge was then finding a microphone that we thought would be able to survive the transit of Earth to Mars, go through the Martian atmosphere, landing on the surface, and could work.
Narrator: A microphone that’ll survive a journey to Mars isn’t something you can just ask for at your local electronics store.
Dave Gruel: I mean, the first response we usually got was, “Haha! Is this my buddy Joe? Are you joking with me? I'm going to hang up on you.” So it took some convincing to communicate to people, “This is real. We have a plan to include a microphone on the next vehicle that’s going to land on the surface of Mars.”
(38:14) But we were able to engage several groups and, in the end, one stood out and their design was already available. You could actually buy their products off the internet, and that's what we flew to Mars as part of the EDL cam microphone.
Narrator: As it turned out, no usable audio was recorded during the spacecraft’s descent, but the mic did record sounds after landing on Mars. And that’s not the only mic on Perseverance.
Dave Gruel: There's another microphone that's on the SuperCam instrument; their microphone also is successfully working on Mars too. So we went from having no microphone sensors on Mars to then having two on the same mission. And it's been exciting because you're now engaging a different human sense. I mean, you don’t usually think of sound when you think of space exploration, and to actually listen to noises that are produced on the surface of another planet, combined with videos and images and other stuff, it just makes that experience even more complete.
(39:19) Narrator: Thanks to these microphones, we can hear gusts of wind blow around the rover as it drives on Mars.
sounds from Mars: rover driving, wind
Narrator: The microphones have revealed that sounds on Mars travel more slowly in the thin, mainly carbon dioxide Mars atmosphere. On Earth, sound typically travels around 767 miles per hour, or about 343 meters per second. But on Mars, low-pitched and high-pitched sounds travel at different speeds: 537 miles per hour, or 240 meters per second, for low pitches, and a slightly faster 559 miles per hour, or 250 meters per second, for high-pitched sounds.
(40:10) Adding to this strangeness, sounds on Mars only carry a short distance, and the higher the pitch, the less the sound travels. You probably wouldn’t even hear sounds occurring more than 26 feet, or 8 meters away from you. Sounds on Mars would seem deadened or muffled compared to sounds on Earth.
Alex Mather’s Perseverance essay, as it would sound on Mars
Alex Mather: We, not as a nation, but as humans, will not give up. The human race will always persevere into the future.
Narrator: What’s also fascinating is how much you don’t hear. The microphones have proved that Mars is a deeply silent planet – so silent, in fact, that the SuperCam team at first thought their microphone was broken.
The microphone on SuperCam does more than just give us rare ambient sounds on Mars. Its main job is to capture the crackle of its laser zapping rocks.
(41:02) sound: SuperCam laser zap
Katie Stack Morgan: That can tell us something important about the material properties of the rocks, as well as tell us about the properties of the atmosphere that those sound waves have to travel through. We turn the SuperCam microphone on during SuperCam observations, but we've also turned the microphone on during Ingenuity helicopter flights, to hear that sound, if there's any sound to be had there.
Narrator: The helicopter Ingenuity is a technology demonstration meant to see whether it would be possible to fly a rotorcraft in the thin Martian air. Here’s Mo Abid again.
Mo Abid: One of the early things that I worked on, on Mars 2020, was Ingenuity, the Mars helicopter. The problem at the time was, where can we fit it? Can we put it on the top of the rover? Shall we put it on the side of the rover? It's not small – it's four-feet-wide blades and we've got an electronic box about six by six by six. So where to place it was a really huge challenge at the very beginning.
(42:01) Narrator: The team ended up tucking the helicopter underneath the Perseverance rover, on its belly. After releasing Ingenuity, the rover rolled a short distance away to see, and hear, whether this bird could really fly.
sound: Ingenuity helicopter flying on Mars
Narrator: Since that first historic flight, Ingenuity has made many more, providing aerial views to help plan the Perseverance rover’s path on Mars. I won’t go deeper into the story of the Mars helicopter now, though, because the next episode will be all about Ingenuity.
After Ingenuity aced its first flights, and Perseverance made sure all of its instruments were working correctly, the rover could get on with the main focus of the Mars 2020 mission: drilling rocks to collect samples.
Katie Stack Morgan: We had selected a good-looking outcrop that we thought would make for a great first rock sample. And when we went to drill it with Perseverance, the tube came up empty to our great surprise.
Katie Stack Morgan: And we said, “Let's look down the borehole with the Perseverance cameras.” Maybe we would see the core pieces still in the hole. And we looked down the hole and that was empty, too. And then we looked around in the area of the rover and said, “Well, maybe the core fell out of the tube when it was being processed.” And we couldn't find evidence for a core anywhere. And so it appeared that our core had just vanished!
Yet it was clear we had made a hole in the surface of Mars, and we had a beautiful tailings pile around our drill – and perhaps too big of a tailings pile, in the sense that ultimately, we concluded that the rock was a lot weaker than we expected. And we suspect now that we basically pulverized it as we did the percussion action with the Perseverance drill. So, we basically turned our core into tailings (laughs) and didn't get hardly any material into the tube itself.
(44:02) Narrator: Although this first attempt to capture a Mars rock came up empty, the team made the best of the situation.
Katie Stack Morgan: While we have a tube that is empty of rock or soil, it is full of Mars atmosphere. So, we officially have designated that first sample to be an atmospheric sample. And there are a lot of scientists back here on Earth who are excited to have a sample of Martian atmosphere, to better understand the composition of the atmosphere and what the environment is like on Mars today and how the atmosphere and climate evolved over time.
And actually, it's quite fortunate in the sense that if we had gotten some small pieces of sample in that tube, perhaps we wouldn't have felt as confident that we could consider it to be the atmospheric sample. If there were any small pieces of rocks, those minerals can undergo changes over time, and so that could have an effect on the atmosphere that you have in that sample. So it was fortunate, in a way, that that sample was as empty as it was, because then we have a pretty pristine sample of Martian atmosphere in there.
(45:06) Narrator: Wanting their next attempt to come up with rock instead of air, the scientists looked for a target that wouldn’t fall apart when they drilled into it, and successfully captured their first rock sample. Sample collection didn’t go completely smoothly from then on – one attempt was foiled because some pebbles got stuck in the rover’s mechanism, and engineers had to try several maneuvers to shake the pebbles loose – but ultimately, Perseverance collected eight rock samples from the floor of Jezero crater.
Perseverance then took a long drive to an area that appears to be a dried-up river delta. This drive of 3 miles, or 5 kilometers, may not seem that far, but Perseverance was able to make longer drives than any previous Mars rover by guiding its own navigation, rather than stopping frequently to wait for directions from Earth.
(46:02) Katie Stack Morgan: It feels like we are just flying by the seat of our pants every day, and that we make it from the beginning of the day to the end of the day is a bit of a wonder (laughs). The whole thing has felt like such a whirlwind. And when I first joined the project in 2017, 2020 and 2021 felt so far away. And then I think a combination of COVID thrown in, the time very much accelerated, and suddenly we found ourselves on the surface. So it's been “go, go, go” since coming onto the project.
Narrator: The mission is supposed to last for at least one Martian year, or 687 Earth days, but the team hopes Perseverance keeps going long after that.
Katie Stack Morgan: I'm excited for us to explore the rocks of the delta. We'll be looking for possible biosignatures in the lake deposits that may be preserved there in the delta. And I'm also excited to drive over the top surface of the delta, where we may have big blocks brought into the crater from outside of Jezero, and so giving us that first look at the diverse ancient crustal rocks outside of the crater.
(47:07) And so, that's what I think the next year and a half or so of the Perseverance mission will look like for us. And then at that point, we’ll be thinking about putting down our first sample cache – some subset of the samples that we've collected thus far in Jezero. And then if the rover is healthy and ready to go, we may consider exploring outside of the crater. So that'll be an exciting way to continue and extend the mission, if we're able to do that.
Narrator: Bringing the promising samples that Perseverance gathers to Earth will be a complex “pass-the-baton” race using some combination of orbiters, rovers, landers, and rockets. Whatever is choreographed for the Mars Sample Return mission will shape how NASA sends humans to Mars. Missions like Mars 2020 and Mars Sample Return are test runs of technologies needed to make a human Mars mission possible, just as robotic missions like Ranger and Surveyor traveled to the Moon before the Apollo astronauts ever suited up.
(48:13) Future Mars astronauts will benefit from fabric samples that Perseverance carries, to see how different suit materials react to the elements on Mars. The rover also has an instrument that tests a way to fuel both astronauts and the rocket ship that would fly them back home.
Katie Stack Morgan: The MOXIE instrument takes carbon dioxide from the Martian atmosphere, ingests it, and basically converts it into oxygen.
The MOXIE instrument is certainly a scaled-down version of the kind of instrumentation that would be needed for future human explorers being able to make oxygen that could contribute to maintaining their Habs – their habitats there on the surface of Mars – and also producing rocket fuel. Rocket fuel is heavy and that can be costly to carry with you. So if you can make that rocket fuel there on Mars, then you don't have to worry about bringing that with you.
(49:08) Narrator: Sending humans is a logical next step in Mars exploration, because being there is far different than experiencing a world secondhand.
Katie Stack Morgan: Back in 2017, we ran an operations exercise with the science team where we wanted to simulate strategic and campaign planning for the rover. So these are the highest levels of planning: what are the main science objectives of the rover at the landing site? And, what are the areas that we want to send the rover to on several-month timescales?
And so, we simulated an activity in the South Bristol Mountains near the Mojave, and they ended up getting the rover pretty close to some tantalizing lake carbonates, but not quite there because they were hard to see from orbit. Had the team planned to go just a little farther around a mound that they were looking at, they could have discovered the ancient biosignatures in the lake carbonate.
(50:01) sound effect: desert wind
Katie Stack Morgan: We were able to take the team out there after we did the exercise, and show them the rocks in person, which is a great exercise to remind oneself that the view that you have from a rover doesn't always tell you the full story (laughs), and what we see with our own eyes can sometimes lead us down different paths than what we see through the eyes of a rover.
Narrator: As someone who knows all too well the difficulties and dangers of sending people into space, Mo still believes in the importance of seeing boot prints on Mars one day.
Mo Abid: We know how to get to Mars. We know how to orbit Mars, we know how to land on Mars. We have a good idea about Mars environments, so now, how to turn that into a human doing it, we're trying to figure out. I hope we’ll be able to land a man or woman on Mars in my time and live there. But if I don't make it, I'm counting on the next generation to make it happen, you know? (laughs)
(51:02) Commuting to JPL, I've got about 45 minutes of drive. So I schedule a conversation through Skype or WhatsApp, whatever it is. Some students have some specific career advice that they need, some others just trying to find their way. You know, a few minutes can change someone's life; a quick conversation can go a long way.
There was a kid's school, actually a robotic team school in Tunisia, maybe six-, seven-year-old kids, right? I just tell them a little bit about what's going on and kind of motivate them and get them excited and all that. And whether it's Mars 2020 or prior missions, it showed that it really doesn't matter where you're from. It doesn't matter what's the color of your skin. It doesn't matter what's your ethnicity, your background. What matters is what you've got in your brain, and what you can do just in general. And so, I've been living with that model and really spread that word among Tunisians, because they've got that mindset of, “Oh, we’re Tunisian, we cannot do this, we cannot do that.” But through mentoring and through talking to a lot of the youth, I was able to help a few and get them to reach their goals and make them believe in themselves.
(52:09) The fact that they see, okay, well, I've got a Tunisian here participating and contributing to one of the most complex robotic missions ever made by mankind. So, if he was able to do it, it's totally possible. I keep telling them, “The only limitation is your own, right? It's the box that you put yourself in it. If you don't have any limitation, any box around you, you're free. You'll be able to accomplish the impossible.”
Narrator: We’re “On a Mission,” a podcast of NASA’s Jet Propulsion Laboratory. If you enjoyed this episode, please follow and rate us on your favorite podcast platform. Be sure to check out our other episodes, and NASA’s other podcasts – they can all be found at NASA-dot-gov, forward slash, podcasts.