Tears for Cassini and All the Other Spacecraft We’ve Loved before
published during a full moon.

As Cassini prepares for its “grand finale,” which includes diving between Saturn and its rings 22 times between April 22-Sept 15, I find myself getting surprisingly choked up about the spacecraft. Even though NASA’s decision to plunge Cassini into Saturn to terminate its mission makes sense (given that no one wants to disturb any life forms that might exist on Enceladus or other moons), the image of the faithful spacecraft plummeting to its fiery end—while still broadcasting information to us—elicits a slew of emotions.

The immense wealth of eye-popping imagery and unprecedented information garnerned by this mission was not merely just scientifically impressive and effective–it also felt like a kind of demonstration of the spacecraft’s “loyalty.” Though Cassini never had an option to be “disloyal” (any malfunction would, of course, not be intentional) and even though it will soon be out of fuel, its final dive feels a little like suicide. I find myself wanting to help Cassini, to make it feel less alone–even though I know it doesn’t feel or think anything. So why do I feel this way? Is anyone else out there getting similarly misty-eyed when considering Cassini’s fate?


NASA’s Cassini spacecraft will make 22 orbits of Saturn during its Grand Finale, exploring a totally new region between the planet and its rings. Credits: NASA/JPL-Caltech

Robotic missions have always been (and continue to be) essential to space exploration. A decade before humans walked on the moon, the USSR’s Luna 2 spacecraft landed on the lunar surface, becoming the first human-made object to touch down off-Earth. In 1966, the USSR’s Venera 3 spacecraft crashed on Venus, and although it wasn’t able to transmit any information, it became the first product of human civilization to reach another planet. Four years later, Venera 7 landed on Venus and successfully broadcast information for roughly 23 minutes. In 1976, the Viking landers made it to Mars.

Until we figure out how to get humans to Mars, Saturn, Jupiter, or anywhere else within interstellar space, we have to rely on robots to explore our Universe for us. Robotic missions give space programs the most bang for their buck—satellites, probes, rovers, and landers can harvest enormous amounts of information in long-duration missions without risking human lives. But there are two problems with robotic space missions. The first is that spacecraft have no intuition, curiosity, or experience. They can’t deviate from their plan to investigate something unusual in the periphery (at least, not without human command). They can’t ask questions. They can’t tell when something isn’t where it should be or has to be moved, like a donut-shaped Mars rock. They don’t know when their wheels have inadvertently dislodged such a rock. There are practical reasons for humans to explore these places instead of robots.


Curiosity celebrates the holidays on Mars. Credit: Dmytro Ivashchenko

The second biggest problem with robotic missions, which may be even more important the first, is that robots don’t inspire people the way humans do. In a 2010 interview with Stephen Colbert, Neil deGrasse Tyson argued that NASA’s astronaut program bolsters American education and motivates students to study science. “When you’re a kid in school, who are your heroes?” He asked. For many of his colleagues, and perhaps for some of us, the answer is easy: astronauts.

We want our heroes to be daring, courageous, and ultimately successful. While robots can demonstrate the latter, Colbert pointed out that “sending robots into space does not win glory for Americans. It wins glory for Roombas.”

“People don’t name high schools after robots,” Tyson agreed.

Not long ago I might have agreed with Tyson. And while I can’t think of the last time I saw a robot on a box of Wheaties, I’m not entirely sure he’s right. It wouldn’t surprise me to see human institutions bear the name of spacecraft that have helped shape human history and culture. After all, there’s a high school in Pennsylvania modeled after the Millennium Falcon.

A tribute to machinery—whether real or fictional—is a tribute to humanity. Spacecraft demonstrate human ingenuity and determination–watching footage of our robotic envoys rocketing through the atmosphere or circling another world gives us a pretty good excuse to feel inspired and declare, “hey, people made that!” In addition to being emblematic of our species’ spirit and intelligence, machines also allow us to extend our reach, to go where no humans have ever gone and may never go (at least, not in a form recognizable to us now). We see through the eyes of Cassini as it shows us the bubbling seas of Titan and the particulate of Saturn’s rings; we see through the eyes of Opportunity and Curiosity as they case out the Red Planet for our eventual arrival. These robots allow humanity to have a presence on other worlds. Our feelings for them stem from their economic and scientific value and their function as our emissaries. But that’s not all.


Robots delivering all the feels. Credit: Disney/Pixar

Humans have feelings for inanimate objects all the time. Ever named a car? Ever called your frozen computer a name? Ever thumped a machine affectionately while calling it “trusty” or “old gal”? We anthropomorphize machines because they make life easier (at least, most of the time). They also seem to have experiences similar to our own: a car wheezes like an asthmatic or a computer struggles to boot up in the same kind of labored fashion as many of us do when dragging ourselves from bed in the morning. It doesn’t matter that those objects can’t feel or think—we can’t help thinking about and feeling for them.

But unlike our cars and computers, spacecraft such as Cassini haven’t directly improved most of our lives in measurable ways. Sure, it provides endless eye candy and some mind-blowing insights about Saturn and its moons, but for those of us who aren’t astronomers or NASA employees, Cassini isn’t as helpful. So why do we get so attached to spacecraft? Well, there’s another force at work here: the media.

In late 2013, China’s Chang’e-3 lander deposited a lunar rover, named Yutu, on the moon. This feat was China’s first celestial landing, and it became the third country to successfully orchestrate an unmanned moon landing. One might think the general public wouldn’t be interested in a machine going to a place where other machines went half a century earlier, but one would be wrong. Even before Yutu left the ground, people felt connected to it because they had been invited to participate in the mission. The name Yutu had been chosen by the Chinese people in an online poll. Yutu means “Jade Rabbit” and is a reference to the rabbit in the Chinese myth about Chang’e, goddess of the moon.

The act of naming is akin to setting an intention or even a benediction. Naming is what parents do–and space agencies realize how much a name bonds the public to a spacecraft or a mission. A sixth grader named Curiosity and other students named Opportunity, Sojourner, and Spirit. China is looking for names for the Martian probe it plans on launching in 2020. But naming is just the beginning. Our attachment deepens as these spacecraft head off into the universe to accomplish their missions. Our hearts pound when we watch dramatic landings, and we get upset when things go wrong. And although the mid-century Space Race riveted the public’s attention like never before, back then, people didn’t have access to mission’s details and daily activities in real time. That access today makes all the difference in how engaged the public feels about a mission.

Initially, both Yutu and Chang’e-3 functioned as planned. They successfully entered into power-save mode during the lunar night–a process referred to by the media as “hibernation” and “sleep,” both of which suggest the machines are alive. But a few weeks after Yutu’s landing, the rover suffered a mechanical problem. Spacecraft have a history of failing—humanity’s success rate for lunar probe missions is just over 50%—so the public naturally feared the worst. The widespread reporting of Yutu’s status triggered an emotional public outpouring of support for the endangered robot.


Chang’e-3 landing site. Credit: NASA

Concerned citizens took to social media to express their wishes to the machine. Sina Weibo, China’s Twitter, was inundated by posts, comics, and photos; the “Lunar Rover Yutu” and the “Jade Rabbit Yutu Rover” accounts snagged hundreds of thousands of followers. Xinhua News chronicled some of the responses: “You have done a great job, Yutu. Hope you get well soon,” one said. A Beijing-based writer, Zhang Yian, posted, “This is too heavy a burden. If the rabbit cannot stand again, maybe we should let it have a rest.”

A Xinhua News report written in Yutu’s voice demonstrated the narrative effectiveness of personification. “Although I should’ve gone to bed this morning, my masters discovered something abnormal with my mechanical control system,” read the report. “My masters are staying up all night working for a solution. I heard their eyes are looking more like my red rabbit eyes. Nevertheless, I’m aware that I might not survive this lunar night.”

It’s easy to forget these words didn’t come directly from the rover itself. The report anthropomorphized Yuto–the spacecraft was supposed to “go to bed,” close its “eyes,” and most notably, instead of the word “function,” its fate was expressed in terms of survival. The effect was heightened when Yutu’s narration also personified Chang’e: “[Chang’e] doesn’t know about my problems yet. If I can’t be fixed, everyone please comfort her.”


Yutu portrait taken by the Chang’e-3 lander. Credit: CNSA/CCTV

Even though it’s absurd to comfort a machine, the idea of Chang’e being left on the moon without its partner—or with its partner’s corpse—is surprisingly sad. I imagine Chang’e shaking its friend and trying to wake it up, not wanting to be all alone so far from home. While this response is all projection, what’s astounding is how easily and naturally it happens.

The end of Yutu’s message yanked hard on the heartstrings:

“About half of the past 130 explorations ended in success; the rest ended in failure. This is space exploration; the danger comes with its beauty. I am but a tiny dot in the vast picture of mankind’s adventure in space. I don’t feel that sad. I was just in my own adventure story – and like every hero, I encountered a small problem… Goodnight, Earth. Goodnight, humanity.”

However bummed humans get when machines malfunction, we can comfort ourselves with the knowledge that machines can’t be scared or sad. But writing reports and social media posts from Yutu’s point of view subverts that notion and leaves readers not just with an unfortunate truth, but with the sense that Yutu is also fully aware of what’s happening and what it means. The personification of Yutu generated such emotion that Comedy Central made the personification literal in a sketch starring Patrick Stewart as Yutu, delivering those last words.

A couple weeks later, the rover surprised everyone by signaling, “Hi, anybody there?” The beloved machine “came back to life” and lasted another 30 months before signing off for the last time, prompting—you guessed it—another wave of emotional goodbyes. “This time it really is goodnight,” the rover said. “There are still many questions I would like answers to, but I’m the rabbit that has seen the most stars.” On Weibo, one user bid Yutu goodnight: “I hope you have beautiful carrot-filled dreams. We are all proud of you.”

Like Yuto, ESA’s Philae lander also elicited a lot of emotion and interest from the public. As the first spacecraft to land on a comet, Philae appealled to scientists and citizens alike, perhaps because there’s something romantic about landing a spacecraft on a comet racing toward the sun, kind of like getting a saddle on a wild stallion.

“We are all proud of you.”

While its deployment from Rosetta went well, Philae never anchored properly into place because its harpoons malfunctioned. Instead, it bounced around on the surface of comet 67P/Churyumov-Gerasimenko, eventually settling into a shadowy spot under a rock. Philae’s stuck situation reminded me of an animal getting caught in a fence—if only it could move, even just a few inches, everything would be okay. But Philae didn’t struggle, bleed, or cry–in fact, it seemed more stoic than mechanical.

In spite of the lander’s inopportune position, it gathered information for 57 hours. It even managed to rotate and get enough purchase to drill into the surface, fulfilling one of the mission’s primary goals. When ESA put Philae into hibernation mode to preserve what was left of its batteries, the media reported that it had “gone to sleep.” After that, Philae’s Twitter account, which had amassed a half-million followers, successfully portrayed the lander as a hero who sacrifices itself to carry out a mission, and won’t rest (temporarily or eternally) until it knows it succeeded.

Just in case the public had forgotten about Philae, a couple months later the account Tweeted: “It’s cold & dark on #67P and the chances of communicating with @ESA-Rosetta are decreasing, but I won’t give up hope just yet.”

As comet 67P/Churyumov-Gerasimenko barreled toward the sun, scientists hoped Philae’s solar panels would pick up enough sunlight to recharge. For a few weeks in June-July 2015, Philae had intermittent contact with Rosetta, but lost contact again in late July, prompting farewells.

Throughout the drama, Philae’s Twitter persona never expressed self-pity, sorrow or fear. It also never referred to itself as dying or even sleeping—just unable to communicate. Philae seemed like a valiant hero who knew its time had come. Philae had just one request: “I’m far from Earth & Sun! I’d love to take memories of YOU with me. Please send me a postcard from home!” It was a savvy move from whoever ran Philae’s account. Soon after, #GoodbyePhilae trended on Twitter and the German Aerospace Center (DLR) encouraged people to share photos of themselves bidding farewell to the lander on social media.

In September 2016, Rosetta pinged back photos of Philae’s final resting spot. The lander was on its side, wedged into a crack in the shadows. ESA senior scientific advisor Mark McCaughrean acknowledged the scientific benefits of knowing where Philae ended up, and noted that “for many people it is an emotional closure.” It’s like recovering the body of someone who had gone missing—some media reports even referred to Philae’s location as its “grave.” While not a happy moment, #Philaefound provided answers to questions and allowed people to let go.


Philae Found. Credit: ESA

Given how many robotic space missions are in operation at any one time, we’ll have plenty of opportunities to develop feelings for our machines. Users are already posting their appreciation for Cassini, with more tributes—and eulogies—to come. When Cassini meets its end, Saturn will no longer be a complete mystery, but we will have lost our eyes and ears in its vicinity, which will feel to some like a death.

Even the other robots are sad.