Season 2, Episode 10: Comets: A Love Story

(music)

[0:05] Narrator: This episode revolves around a love story. Love between a man and a woman, but also the love they shared for exploring the universe.

Carolyn Spellmann met Gene Shoemaker in 1948. Gene was her brother’s college roommate, and the best man at his wedding. Here’s Carolyn.

Carolyn Shoemaker: For a few days before the wedding, my brother and his to-be wife, who was my best friend, and Gene, went out and did various things, exploring the area and just having fun. I was growing to like Gene more and more as time passed. He always seemed so willing to do anything, and he seemed to enjoy everything that I seemed to enjoy. So I thought, "Well, we sure have a lot in common."

[0:53] Narrator: Gene must have felt the same, because after he left, he wrote Carolyn long letters.

Carolyn Shoemaker: After my brother's wedding, Gene had to go back to work at the US Geological Survey in Grand Junction, Colorado. He was looking to find a new source of uranium. So he was there for a while, and he went from there to Princeton to work on his PhD, and I knew that was going to take a long time. I was just thinking I might never see him again. So while we had been writing letters back and forth, I stopped writing, and he noticed right away and he wrote me a letter and said, "Please keep on writing." (laughs) So I did.

(music: “I’m All Shook Up,” performed by Elvis Presley)
“I'm in love
I'm all shook up”

[1:46] Narrator: Gene and Carolyn corresponded for a year. Then he suggested they go camping together on the Colorado Plateau, bringing Carolyn’s mother along.

Carolyn Shoemaker: This in part because, as a young woman, I couldn't possibly make such a trip without a chaperone, so that was going to be Mother. He had already spoken to her, and Mother loved going camping, and so we did make that trip after school was out.

My mother and I drove to Grand Junction. That was exciting to me to begin with because I hadn't been very many places. I'd grown up during the wartime years and you didn't just travel. We got to Grand Junction and met Gene, and we went here and there around the Colorado Plateau. I didn't know the geology at all. Gene would explain the formations and what they were, teach me to recognize them. We traveled through enough variety of country that there was always something new. We just had a very good time. And that first night, he asked me to marry him.

He said something to the effect of, "What do you think it would be like to be married to me?" And I thought, "Is this a proposal?" (laughs) I said, "I thought it would be fine." So we went for a few days without saying much about it, and Mother kept saying, "Did he propose or not?" Finally, she asked him, and yes, (laughs) he had proposed, and so we started planning the wedding.

[3:34] Narrator: Gene and Carolyn married on August 18, 1951: exactly a year after her brother’s wedding. The wedding took place in Chico, California, Carolyn’s home town. The day was blazing hot: they married in the morning to avoid the worst of the heat, but the temperature had already climbed to 118 degrees Fahrenheit when they said their vows.

(music: “I’m All Shook Up,” performed by Elvis Presley)
“When I’m near that girl that I love best
My heart beat so it scares me to death…”

[4:02] Narrator: The newlyweds were soon back in the Colorado Plateau, continuing Gene’s geological fieldwork. Rather than pitch tents, they would sleep out under the stars.

Gene had his eyes set on the brightest object in that night sky: the Moon. Ever since he was a kid devouring tales of science fiction, he dreamed about going to the Moon. People laughed and said going to the Moon was an impossible fantasy.

Gene’s studies of craters on Earth naturally caused him to wonder about the craters on the Moon. Those studies brought them to Meteor Crater in northern Arizona.

Carolyn Shoemaker: We got there just at dusk, when the light was changing and beginning to fade. We didn't have any money left after buying the gas, (laughs) so we didn't go around to get to admissions. We went up the side of Meteor Crater and peered over the rim. And Gene was entranced.

[5:01] Narrator: At the time, the crater was not thought to be the result of an asteroid impact, but instead, the remnant of a dead volcano.

(music: “I’m All Shook Up,” performed by Elvis Presley)
“Her lips are like a volcano that's hot
I’m proud to say that she’s my buttercup
I’m in love, I’m all shook up…”

[5:16] Narrator: The same year Elvis Presley’s song “I’m All Shook Up” was shaking the airwaves, the Soviet Union launched Sputnik, the first satellite to ever orbit the Earth.

Sputnik CBS news report:
“Was it a surprise to you that they got there first?”
“Well, it was something of a surprise. And naturally, since this generates a certain amount of scientific rivalry, something of a disappointment to us. But this does not lessen our admiration of what the Soviets have done.”
“Moscow has not been passing up its opportunities, as CBS news correspondent Dan Schorr observes, in a recorded report from Moscow.”
“Although the main Soviet papers today devote more than half their space to the satellite, with front page banner headlines such as rarely seen in this country, there are precious few scientific details being divulged…”

[6:01] Narrator: After Sputnik circled the globe and shook up the US, the Soviets followed with other feats, including sending the first man – Yuri Gagarin – into orbit around the Earth. The battle for space dominance had begun.

President John F. Kennedy Speech to Congress, May 25, 1961:
"If we are to win the battle that is now going on around the world between freedom and tyranny, the dramatic achievements in space which occurred in recent weeks should have made clear to us all, as did the Sputnik in 1957, the impact of this adventure on the minds of men everywhere who are attempting to make a determination of which road they should take.”

[6:43] Narrator: When President John F. Kennedy made this iconic speech to Congress in May 1961, Gene Shoemaker’s Moon fantasy suddenly become a reality.

President John F. Kennedy: “I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to the Earth.”

Carolyn Shoemaker: It wasn't just to get a man to the Moon and back safely. It was to get a man to the Moon, get a lot of information, and then come back. (laughs) That was Gene's thought. He really talked up the subject of getting a scientist onto the Moon. And of course he really hoped it would be him, because he'd always wanted to go to the Moon.

[7:31] Narrator: Like President Kennedy, Gene developed Addison’s Disease, a disorder of the adrenal glands. Medicine helped keep it under control, but it meant he couldn’t be an astronaut due to the strict medical requirements. So Gene used his passion and knowledge about the Moon to train the astronauts at Meteor Crater and other lunar-like sites in the high desert. When Neil Armstrong and Buzz Aldrin set foot on the Moon, they were better prepared for what they saw largely thanks to Gene Shoemaker.

Buzz Aldrin: “That looks beautiful from here, Neil.”
Neil Armstrong: “It has a stark beauty all its own. It's like much of the high desert of the United States. It's different, but it's very pretty out here.”

(musical intro)

[8:45] Narrator: Welcome to “On a Mission,” a podcast of NASA’s Jet Propulsion Laboratory. I’m Leslie Mullen, and this is the final episode of our second season. Episode 10: Comets: A Love Story.

(music)

Comets are essentially asteroids that are heavy on the ice. They’re icy because they come from beyond the “snow line” of our solar system, out where the ice giant planets Neptune and Uranus orbit, where Pluto and his brethren dwell in the dark. The light from our Sun barely graces the comet’s realm. But sometimes comets get a passport to a more tropical climate, to the warm inner solar system enjoyed by Earth, Mars, Venus and Mercury. As the comet nears the Sun, its ice turns to a gas and streams off as water vapor, creating a glowing coma and a spectacular tail.

As beautiful as they are, comets have a darker side.

Throughout history comets have been seen as evil omens, predicting horrible events including famine, plague and war. This fear of comets exists even in more modern times. In 1910, word spread that the tail of Halley’s comet was a deadly gas that would envelop the Earth. Anti-comet pills and gas masks did a brisk business despite the reassurance of most astronomers.

Comets can be dangerous, though. Steve Chesley keeps track of comets at the Jet Propulsion Laboratory.

Steve Chesley: Because their orbits are eccentric, elongated, they are moving much faster than asteroids are when they come into the area around the Earth, and so comets pack a bigger punch. Adding to that is the ones that are coming from the far, far reaches of our solar system, these appear not to be small. And so not only are they going faster, but they're probably larger.

If we see something coming, first of all, we're not even going to know because of outgassing whether or not it's actually going to hit the Earth until very late, and then what do you do with something that's 10 kilometers in size that's probably headed for you? With current surveys, you would see it when it passes Jupiter, maybe Saturn, probably. So you would have a year or two of warning.

That's a kind of hazard that’s truly catastrophic for the globe, for the planet. You think dinosaur killer. That was 65 million years ago. This is even worse.

But these events are very rare. We're talking about billion-year events, whereas asteroid impacts on the Earth might be thousand- or ten-thousand-year events, and so that's why most of our effort is on the asteroid problem. We'll get hit by 100,000 asteroids before we get hit by another comet.

[11:26] Narrator: Luckily, there aren’t a lot of comets in the inner solar system, and the ones that do come through our neighborhood eventually disintegrate after many passes around the Sun.

But the threat of large asteroid and comet impacts was one reason Gene Shoemaker began the Palomar Asteroid and Comet Survey in 1983. After blazing his way through a stellar career as a geologist for NASA’s lunar space program, and revolutionizing our understanding of craters on the Moon and Earth, Gene had become a professor at Caltech and developed a new passion.

Carolyn Shoemaker: He always thought big, so he wanted to start a program to look for near Earth asteroids, especially those that might hit the Earth. The Palomar Observatory was owned by Caltech, and that made the whole thing ideal because it didn't cost anything for them to go up and use a telescope. And they went up and organized the project around the 18-inch telescope. That's the oldest, the smallest telescope on Palomar Mountain, but it was designed to be used for photography, and that was the way they did their search. They would put film in holders, and take images maybe an hour apart, and then look at them under a microscope, and anything that appeared to have moved might well be an asteroid, so they would study it further.

[13:05] Narrator: During much of Gene’s career, Carolyn had stayed home to raise their three children. Eventually the children grew up, and at age 52, Carolyn found herself at loose ends.

Carolyn Shoemaker: About that time, I said, "Gene, do you have any idea of something I could do that would interest me as much as geology interests you?" Meaning 48 hours a day. He said, "Well, I have this little project up at Palomar." He said, "Why don't you take a look at some of the glass plates.” You put them on, what was known in those days, a blink comparator, side by side, the plates and the lights would flash behind one or the other very quickly, and you could discover movement that way. So I learned to do that, and I kind of enjoyed it.

And then Gene and the young woman he was working with, Eleanor Helin, decided to get an instrument where you could put films side by side and the microscope above, and a light underneath the films. You look at the films as if they were one. That way, anything that moved, like an asteroid or a comet, would appear to float above the surface. That was pretty exciting. Eleanor tried that for a little while, but she didn't have very good stereo vision, and that was what you needed to do this. So Gene brought the stereo microscope home along with some films. He said, "Let's try this out, and see if you'd like it." He and I both had a lot of fun doing that, and he realized that I could see things very well. So that became my job, to look at things on the stereo microscope.

I really enjoyed it. You know, it's kind of fun to go along looking at something and then have an asteroid or a comet pop up above the surface, (laughs) and realize that that was something that was new and something that was important that you were looking for.

[15:30] Narrator: When Gene suggested she join him to make observations at the telescope, Carolyn was hesitant; she wasn’t sure she could stay up all night. It wasn’t long, though, before the couple were spending their evenings together again under the stars.

Carolyn Shoemaker: I made a number of trips with Gene, just to discover things on the 18-inch, and he and I had a good time together doing that, and then he went over to the 48-inch to work with Eleanor Helin on the same sort of thing and left me at the 18-inch. It was sort of like a second honeymoon, but when he went off, I found myself singing a song, "Now I can do it my way." (laughs)

(music “My Way,” performed by Andre Rieu)

[16:32] Narrator: Only a dozen or so near-Earth asteroids and comets were known when they started the project. At the time, not many people were interested in tracking them down. Within ten years, the Shoemakers were leaders in asteroid and comet discoveries.

Carolyn Shoemaker: I found a number of comets, but there was one that was more interesting than all the others put together.

(music)

Gene and David Levy and I and a young Frenchman, Philippe Bendjoya, who was visiting, were at Palomar. It was kind of late in the spring and we hadn't found much most of the winter. The weather had been bad. When you are signed up to go to a telescope at Palomar, you go, whether the weather is good or not.

When we went, we took some film that had been in a storage box beside the table where I kept the stereo microscope. We took that film, and it was important to use that because we would hyper the film to speed up the emulsion. That meant that we cut out the little round circles of film, six-inch circles, and then we would put it in an oven and bake it. By so doing, we could speed up the emulsion, and instead of having to take exposures that were an hour long, we could take 10-minute exposures. That was great. It meant that we could do a whole lot more in an observing run.

So the first night, we discovered that the film was not so good (laughs) because someone had opened the box and exposed all the film and then closed the lid and not said anything to me.

Gene looked at the film in the box, and by digging down into the middle of the pile, he could find enough film that we could take some images that night. They weren't very great. The edges had been exposed but not the middle, so that was what we took. Then the second night, we were all set to take some exposures, and we discovered that clouds were beginning to come over. We would look at the sky and the clouds and say, "You think we can take any?" "No." David Levy would say, "Why don't we try some of that film that was not good yesterday. It won't cost us anything, and we might get something at least."

And so that night, he and Gene rushed in to the telescope and set up, and before the clouds came entirely, they managed to take a few films. Later, the fourth night or fifth night of the observing run, it was raining outside. Gene was reading Time magazine. David was looking at his computer, and Philippe was out in the car sleeping. I was looking at the films.

And my process was to start at the top and move slowly across the film and then down and back and so on across the film. All of a sudden I realized there was something strange, and I backed up, and there was this strange-looking object, and I didn't know what it was. I thought, "Well, it's probably some effect from Jupiter," which was on the film, and which often had rays coming out from it and other effects on the film.

I moved the film around, and I looked at the position of Jupiter and the position of my film and thought, "No, Jupiter didn't have anything to do with this." And it was strange because it almost looked like a line of fuzzy comets. So I said, "You know, I don't know what I have here. Would you take a look?" And Gene came rushing over. He was just amazed. He couldn't figure it out either, and David came and looked, and Philippe came in from the car and looked. We all thought, "What can it be?" Well, we reported the position to the Minor Planet Center in Cambridge, Massachusetts. And Gene remarked, "I wonder if that's a broken comet."

David knew that Jim Scotti at the telescope in Tucson might be observing that night, and maybe he could take a look at this strange object for us. He was using a telescope that was quite a bit bigger than our 18-inch, so he could see this strange thing more clearly. And he called Scotti, and Scotti said, "Well, I've got an awful lot to do, but I'll take a look at your object if I have time." In short order he called back and he said, "Boy, have you guys got a comet."

[22:12] Narrator: Gene’s instinct was correct. The comet was broken into a row of fragments, each with their own tail. The comet fragments were lined up like a string of pearls.

Carolyn Shoemaker: Those little comets were really quite remarkable. They were fragments of an impact that had broken up the comet, and as fragments, some were bigger and some were smaller.

[22:35] Narrator: The comet fragments ranged in size from a kilometer to a few hundred meters. Paul Chodas, the current head of CNEOS, JPL’s Center for Near-Earth Object Studies, led the team that figured out the precise track that the comet fragments were on.

Paul Chodas: It was soon discovered to be, once we did the math, in orbit around Jupiter. Whoa! That's really bizarre. A comet orbiting Jupiter. That doesn't happen very often. The Minor Planet Center sent an email and said, it looks like the next time it goes near Jupiter, it’s going to hit. And that was yet another “wow” moment, because this would be the first time we could witness a giant impact, fortunately on another planet, and predict it.

[23:17] Narrator: Astronomers had never before seen a planet get hit by a large comet. Everyone was paying attention now. Telescopes all over the world swung around to watch this historic event.

Carolyn Shoemaker: The second month that we were observing, David got a message from the Minor Planet Center saying that this comet was going to hit Jupiter. Well, (laughs) after that, the scientific world sort of exploded, but it really exploded in the little 18-inch dome. David was so excited and pleased, and he was jumping up and down, and Gene was in the dark room at that moment trying to get film ready for that night. He heard the excitement, and he slam, bang, with the lids on various containers. He came out and rushed over to David's computer and took a look at the message and was so excited. This was the comet he always hoped to see.

I was dismayed. I thought, "Oh, I'm going to lose my comet. I've never lost a comet before. I have a whole bunch of comets that I can see every now and then, and I would never see this one again." (laughs) But after a while, I came around and I was excited too.

[24:39] Narrator: Gene later gave her a gift to replace the lost comets.

Carolyn Shoemaker: Oh, yes. Gene gave me a string of pearls in commemoration of what we had found, and they were beautiful.

[24:53] Narrator: The cometary string of pearls was beautiful but deadly -- each one was large enough to destroy an entire region on Earth. There were 21 one of them, a merciless line-up that would hit Jupiter again and again, separated by mere hours, each time striking a different spot as the gas planet rotated. Here’s Paul Chodas again.

Paul Chodas: When and where it's going to hit was a whole story also. Because you're projecting ahead in time, and my indications were that it was going to hit on the far side of Jupiter as viewed from the Earth, so we couldn't see it directly from the Earth. However, Galileo, the spacecraft, was on its way to Jupiter and it had a different view, and it could actually see the impact spots as they occurred.

Before that, we were wondering whether there would be anything at all. Are we going to see a flash or will there be a big fizzle? Each of the impacts, especially the first one, is an exciting time, because we're going to see what happens. And in the infrared, which is measuring heat, there was a clear detection of a bright spot on Jupiter. I was all excited. It really did hit. It's a spot we predicted. It looks like we're going to have 20 more of these impacts to observe.

And sure enough, as bigger fragments hit, you saw the Hubble Space Telescope images of the big splots on Jupiter. It happened over a week. So we'd have one or two a day. That was millions of megatons by some measure. Millions of megatons. Now, those black marks are just what's left over of the comet dust and material, but the size was bigger than the Earth.

[26:26] Narrator: Jupiter is more than 11 times larger than our planet. You could fit 1300 Earths inside of it. If the string of comets had hit Earth instead of Jupiter, we might not be here to talk about it.

Paul Chodas: Jupiter has a bigger gravity field, so it's pulling things in easier than the Earth would. So the Earth is less likely to be hit, especially by comets, but it's still possible. And so that opened a lot of eyes in the scientific community, and in Congress frankly. And they recognized that these surveys, that were being done by educational institutions like Caltech and Gene Shoemaker's efforts run through JPL, deserve better funding, and should be done more thoroughly and to better sensitivity. So that really kicked off the Near-Earth object program.

(music)

[27:10] Narrator: Shoemaker-Levy 9 started a new age of asteroid and comet detection for NASA. This year marked the 25th anniversary of the comet fragments hitting Jupiter.

We now know that tiny asteroids hit Jupiter every year or two. But these impacts are much smaller than the Shoemaker-Levy comet fragments, and not large enough to even leave a dust scar on Jupiter.

Over the past 25 years, astronomers have found nearly all the near-Earth asteroids and comets that are a kilometer in size or larger, and a good portion that are even smaller. For instance, NASA’s SOHO spacecraft – a solar observatory – has spotted thousands of comets as they made a death-spiral into the Sun.

We don’t just observe comets from afar, we’ve also sent spacecraft to study them up close. Starting in the late 1970s, NASA, Russia, Japan and Europe all sent missions to comets.

The European Space Agency’s Rosetta mission was the first to put a lander on a comet in 2014, and although the lander’s harpoons didn’t work and the lander bounced all around, it was still able to send back information. Rosetta showed us that a comet is an active place, with rolling boulders, landslides, and ever-widening cracks as it gets heated by the Sun.

As mentioned in episode five, we got a sample of a comet when NASA’s Stardust mission captured a few dust particles from a comet’s coma. Missions like these have revealed that we may have comets to thank for our existence. Life on Earth likely arose in water, and depends on water for survival. The frozen ice on comets is chemically very similar to the water on Earth, so many scientists think Earth’s oceans came from comets.

Steve Chesley worked on the Stardust mission.

Steve Chesley: One of the things I have done at JPL since almost as soon as I got here is work on computing the trajectories of comets for spacecraft flybys. I was making sure that the comet was there when they arrived.

[29:09] Narrator: Steve also figured out the orbit of comet Borrelly for NASA’s Deep Space 1 mission, and the orbit of comet Temple 1 for the Deep Impact mission. As mentioned in episode four, Deep Impact didn’t just flyby in 2005, it also hit the surface of the comet with a copper cannonball.

Steve Chesley: After the Tempel 1 impact by Deep Impact, the one disappointment from that mission was they never really got to see the crater, in particular the size of the crater, which was scientifically important. There was so much dust and it was so fine and it didn't disperse rapidly enough, and that flyby was too fast, and the dust was still blocking the view of the crater itself.

[29:46] Narrator: Spacecraft that finish their missions often just end up orbiting the Sun. But if there’s still enough fuel on board, sometimes you can steer it towards a new target. Engineers realized that if they brought the old Stardust mission back to life, it could fly by comet Tempel 1 and look for the crater made by Deep Impact. So the spacecraft got a new name, Stardust-NExT, along with a new destination.

Steve Chesley: Comets are not that easy to get to because they have such high velocities. Even for flybys it's not that easy to get to a comet with one mission, let alone to get to two comets with one mission. So that was, I would say, a very clever trajectory design that probably isn't going to happen very often, if ever again, to get to two comets with one spacecraft, especially when the second flyby was really not planned. The spacecraft had to survive much longer than it was designed for.

One of the things I worked on for Stardust-NExT, besides making sure that the spacecraft team knew where the comet was so they flew by in the right time and place, was to make sure that when the flyby occurred, that crater that Deep Impact had created was on the correct side of that comet. It's rotating and we wanted to make sure that when the spacecraft did fly by, the side of the comet that had the Deep Impact crater was visible to the spacecraft. It would be awkward if it were on the wrong side of the comet when the spacecraft flew by. Well, that was harder than it might seem because this comet had its rotation period changing with time.

[31:16] Narrator: The comet had traveled completely around the Sun by the time Stardust-NExT reached it. The comet had changed so much, the crater made by Deep Impact just six years before was barely visible.

Steve Chesley: You got to sort of squint and use just a tiny bit of imagination or stereo glasses. It’s not obvious. It had been eroded quite a lot. One of the reasons, besides just seeing the crater and seeing how big it was, is to see how Tempel 1 had evolved in one revolution around the Sun. And not only the crater had eroded, but many features on the comet were clearly different.

[31:50] Narrator: Stardust-NExT’s flyby of comet Tempel 1 was remarkable, a once-in-a-lifetime alignment of celestial bodies. But Steve has another reason to celebrate that day.

Steve Chesley: Well, the Stardust-NExT flyby of Tempel 1 was on February 14, 2011. I had met this lady, Jana, as a part of my work on the team, and we had started dating, Jana was collecting observations of the comet.

(music)

And it came time to have the flyby on Valentine's Day, and I decided this was a good day to propose.

I had been planning for some time, and I looked around for engagement rings and I found a company called Stardust that makes engagement rings. So there we were on Valentine's Day, flyby day, and the mission was Stardust, the ring was Stardust, and it seemed like it was too rich of an opportunity to let pass by.

So as part of my daily briefing to the science team, I had a PowerPoint with a few extra slides showing some pictures of us, and proposed marriage to her at the science team meeting.

And I’d asked the PI in advance if it was okay if I did this and he said, "Oh, sure, sure, sure." And then his wife and Jana were out somewhere, and so the PI basically went and found them and urged them to hurry up and get to the meeting because they didn't want to be late for this one. So she managed to show up on time. She hadn't been expecting it, and she said yes. There was a lot of claps. People were even crying. So there was a lot of excitement. And then of course we got down to work for the flyby.

One of the first things after we got married, Jana and I got a dog, and because we both worked on comets and we'd met on a comet mission, we decided to call this dog Komet, K with a K. So Komet is an Australian Shepherd and he kind of looks like a dirty white snowball. And unlike most Australian Shepherds, we decided that this dog should keep his tail.

And that was 2011, more than eight years ago, and we now have a three-year-old and a five-year-old daughter, and we still look back with fondness on the Stardust-NExT mission.

[34:12] Narrator: Eugene and Carolyn Shoemaker discovered hundreds of asteroids and 32 comets. They also studied impact craters that are made when asteroids hit. In the early 1980s, they realized Australia has a lot of old craters.

The Australian continent is quiet, geologically-speaking, and because it doesn’t change much, it holds on to its impact craters.

So the Shoemakers returned time after time, traveling around the Australian Outback for three months each year. It was the type of adventure that had always bonded them together: immersed in the glories of nature, sleeping out under the stars.

Their explorations required tumultuous off-road driving. The extreme jouncing led to sheared bolts meant to keep the car together, and pieces of their vehicle would sometimes fly right off. They had to navigate rivers, mud holes, and deep sand. Burst tires were a frequent occurrence.

Carolyn Shoemaker: All of the roads were known as tracks in the Outback, and they were pretty rough. Some of them were in areas where there had been fires going across the landscape. When eucalyptus burns, it leaves a little spike of itself sticking up. Nothing like driving across that spike. (laughs) Generally speaking, whenever we drove across country or even on the tracks, we would have at least one flat tire a day. Gene was a pro at fixing flat tires. 23 flat tires was our record.

[35:53] Narrator: Sometimes a tire would get so jammed in its rim, it seemed impossible to pry it loose. But Gene had an idea: laying the tire on the ground, he and Carolyn stood on top of it, held hands, and danced until the tire was freed.

(music: “Dolly Dimple Dance,” performed by Slim Dusty)
Play a tune that's sweet and simple,
We'll all dance the Dolly Dimple,
All join hands and circle around the floor…

(music)

[36:18] Narrator: In July 1997, three years after the Shoemaker-Levy 9 comet hit Jupiter, the Shoemakers were on their twelfth Australian exploration. By this time, they were well-seasoned Outback adventurers. Their car was their own little spaceship, rocketing around the vast emptiness of the Australian desert.

On this particular day they were driving through the Northern Territory, on their way to the Western Australia border toward the Goat Paddock impact crater. It’s thought that this 3-mile-wide crater was made less than 50 million years ago when an asteroid hit Earth. But the crater was not well-studied, and the Shoemakers were looking forward to exploring it.

Carolyn Shoemaker: We had been driving for two days, and we were approaching the border of Western Australia and South Australia. We had not seen another vehicle for a day and a half, since we had left the Great Northern Highway and started on this track. It was a big wide dirt track, and we were driving as all Aussies do in the Outback. Everyone drives down the middle of the road. That was the smoothest place. And so, we were going around that curve in the middle of the road, and when we glanced up, why, there was a Land Rover right in front of us, and we impacted.

(music ends abruptly, with impact stinger)

[37:55] Narrator: This impact shattered their world forever. Gene died in the crash. He was 69 years old.

Carolyn Shoemaker: When the impact occurred, I was thrown down on the controls down on the bottom. And in the other vehicle, the people were hurt a little bit but not very much. They came and checked, but quickly went back to their own vehicle and we waited.

I had been wondering as I lay there in the bottom of the car why Gene didn't come around and open the door and get me out, because that's what he would ordinarily have done. But of course, he couldn't.

After a while, here came another vehicle. It was from a gold mining camp and they called the Royal Flying Doctor. And they came, and also brought the jaws of life and pried the door open and got me out and into the airplane, and then told me that Gene was dead.

So I went back to Alice Springs, and I was there in the hospital for a number of days. I had broken ribs. I had sprains here and there. I was really in pretty bad shape. I couldn't walk for a while. My hands still show the effect, and wrists, of the impact.

[39:28] Narrator: Gene was cremated, and his ashes were scattered at Meteor Crater. He’d been instrumental in proving how that crater was made by an asteroid impact, not by volcanism as had been widely believed. And of course, Meteor Crater was where he’d prepared Apollo astronauts for their voyages to the Moon.

(music: Love theme from “Romeo and Juliet,” performed by Andre Rieu)

Carolyn Shoemaker: The family took a fair amount of his ashes out to Meteor Crater. It was a cloudy day. The wind was blowing, and then as we scattered the ashes, the Sun came out and we thought, "Hah, he's home again!"

[40:09] Narrator: But not all of his ashes went there. Some of them took a much longer journey.

Carolyn Shoemaker: While I was still in the hospital, I had a call from Carolyn Porco. Carolyn Porco had been one of Gene's students at Caltech, and she said that Lunar Prospector, a mission to the Moon, was going to be leaving shortly, and we could possibly put a capsule of Gene's ashes on it and he could go to the Moon. And I was thrilled by that.

[40:43] Narrator: The year before his death, Gene had said in an interview, “Not going to the Moon and banging on it with my own hammer has been the biggest disappointment in life.''

Carolyn Shoemaker: The whole family went to see Lunar Prospector liftoff. We were pretty excited. Gene had always wished he could go to the Moon, and now he was going to go. We saw the liftoff, which was both happy and sad. We feel like his dream really did come true.

[41:16] Narrator: Along with some of his ashes, the spacecraft included an inscription from Shakespeare’s play, “Romeo and Juliet”:

(Libivox recording: Romeo and Juliet, Act 3, Scene 2
And when he shall die,
Take him and cut him out in little stars,
And he will make the face of heaven so fine
That all the world will be in love with night,

And pay no worship to the garish sun.

[41:38] Narrator: After orbiting the Moon for a year, collecting data and surveying its many craters, the spacecraft made a planned crash-landing into one of those lunar craters in 1999. That crater in the Moon’s south pole was renamed “Shoemaker” in his honor. The man who had dedicated his life to studying the Moon, asteroids, and impact craters had himself become a Moon-impacting asteroid, his ashes becoming one with the lunar dust.

Carolyn Shoemaker: I look up at the Moon and I think Gene's up there. I wave at it in my mind and I say, "Hi, Gene, how are you doing? Are you finding a lot of interesting rocks?" And he would say, "This is great stuff. Wish you were here!” We hold a little conversation.

[42:29] Narrator: The lunar crater is not the only outer space tribute to the legacy of Gene and Caroline Shoemaker. The NEAR spacecraft was rechristened NEAR-Shoemaker as it flew towards an asteroid named after the Greek god of love, Eros. That spacecraft began orbiting the asteroid in the year 2000, on Valentine's Day. And, almost exactly a year later, NEAR-Shoemaker embraced Eros, touching down on its surface as gently as a kiss.

(music)

[43:10] Narrator: If you like this podcast, please subscribe, rate us on your favorite podcast platform, and share us on social media. We’re “On a Mission,” a podcast of NASA’s Jet Propulsion Laboratory.

Run time = (43:25)