A Majestic End for a Faithful Friend

by Shane L. Larson

We live in an age where digital technology can make anything seem real. Movies have become immersive experiences where any landscape, real or imagined is possible. Physics defying stunts are rendered on screens as tall as buildings and with sound louder than thunder. Creatures long extinct or completely imagined spring to life, and actors long since passed from the world magically return to the screen, appearing as they did in their youth. Anything seems possible, and the boundaries of reality are blurred, to say the least.

Anything can be given realism with modern technology, whether they be long dead creatures, imagined aircraft, or an architectural plan for a new building. [all images from Wikimedia Commons]

We are so used to this, that when confronted by real pictures of the real world, we often forget what we are looking at. Fantastic and awe-inspiring pictures slip past us and don’t always capture our attention. Photographers capture massive migrations of animals across the land and sea, forlorn sights of abandoned corners of our cities, and the vibrant colors of rainbows and autumn leaves. When we see those pictures, at just the right moment, we experience a visceral moment of joy and set our phone screens and computer desktops to the image, to remind us of that moment of wonder. But more often than not, we don’t remember that real pictures of the real world can evoke emotional responses in us. Some small part of our brain remembers, of course, else we wouldn’t takes selfies in front of restaurants where we enjoy fantastic dinners, or pictures of sunsets against the skyline of our backyards.

On many days, as the woes of the world sidle past me on my computer screen, I am reminded of something that I became aware of in my youth: the true masters of real pictures of the real world are the folks at NASA. They have long been part of the storytelling narrative, reminding us that we are part of a far larger Universe, showing us that with concerted effort and imagination and perseverance, we can overcome tremendous obstacles, solve incredibly difficult problems, and discover that the world around us is filled with unimagined and awe-inspiring grandeur. The Cosmos is alive and breathing around you, reminding you that you are part of something greater that the usual bibble-babble washing out of your device screen.

NASA’s digital artists are masters of putting us at the center of the action, even if it is impossibly far away. L to R: Curiosity skycraning onto Mars; Juno arriving at Jupiter; Cassini arriving at Saturn. [Images by NASA]

In the last few years, our friends at NASA have upped their game. Not only have they regaled us with real pictures of the real world, but they’ve picked up the story-telling torch, and as masterfully as any filmmaker in the world catapulted us into the drama of exploring the Cosmos. You may remember this when they told us about the Seven Minutes of Terror as we lowered the Curiosity rover onto Mars using a robotic, rocket-powered skycrane. Last year, they told us the tale of returning to the unknown regions around Jupiter with a hearty spacecraft called Juno, diving into the radiation belts where anything could happen. But recently, they turned their attention to a far-away world called Saturn, and a steadfast spacecraft we sent there called Cassini….

Saturn has been known to humans since antiquity, one of the bright moving lights in the sky known as the planētes asteres, the “wandering stars.” Like the other naked eye planets, Saturn moved slowly among the stars, tracing out a path along the band of constellations known as the Zodiac, cementing itself in the folklore and mythology of sky-gazers who watched it closely. In the 17th century, the era of Saturnian exploration began when the first telescopes were pointed skyward. The first fuzzy, warbling views of the world showed it was not like the stars at all. Telescopes improved rapidly, as did the views they showed of this far away planet, until at last we discovered the truth — Saturn was magnificently bejeweled by a brilliant, encircling ring. Since that time, Saturn has reigned supreme among all the planets for the awe it evokes at its splendor and beauty. More than any other planet, it looks like it is supposed to look. Today, millions of telescopes around the world are set-up in backyards and on sidewalks on clear nights, giving ordinary people like me and you views of one of the Cosmos’ great spectacles — you can have your own Saturn Moment.

View of Saturn you will have through a modern backyard telescope, taken with an iPhone [Image courtesy of Andrew Symes]

Like most things in space, Saturn is unfathomably far away. At a distance of 1.3 billion kilometers from Earth, it would take you about 1400 years to drive to Saturn’s orbit in your car, or about 150 years to fly there at the speed of a passenger jet. We are, by and large, restricted to staring at it from afar, gleaning what we can from the meager light gathered in our telescopes. The arrival of the Space Age put a new possibility on the table: travelling across the void. Suddenly, we had the chance to see Saturn up close.

While there are effervescent dreams to send humans, Saturn is still too distant to imagine easily crossing the void ourselves, so our attention has been focused on sending quasi-intelligent emissaries in our stead: robotic explorers whose sole purpose is to gather as much information and take as many pictures as possible, and transmit all of that information back to Earth.

Our robotic emissaries, Pioneer 11 (left) and Voyagers 1 and 2 (right). These are the only spacecraft to have ever visited the gas giant worlds of the Solar System. [Images by NASA]

In the 60 years since the start of the Space Age, only 4 spacecraft have ever visited Saturn. The first was a resolute robotic explorer called Pioneer 11.  In 1979, it flew by Saturn skimming through just 20,000 kilometers above the cloud tops, returning the first up close pictures of Saturn, but only a few. It was followed by Voyager 1 in 1980, and Voyager 2 in 1981. The Voyagers returned wide planetary views of Saturn that became iconic to an entire generation of humans, and showed us an ensemble of moons that are each unique and tantalizing, demanding their own careful program of exploration. All of these missions flew past Saturn, returning quick passing views before sailing onward. Today, Pioneer 11 and Voyagers 1 and 2 are on an unknown voyage, destined to drift in the great cosmic dark between the stars for a billion years.

Closeup views of Saturn by Pioneer (left) and Voyager (right). Their time with Saturn was short because they were doing flybys (try taking a picture of your friend on the sidewalk as you drive by at 50 miles per hour…). [Images by NASA]

The most recent of the quartet of august explorers is a two tonne spacecraft called Cassini. It spent seven years crossing the void to Saturn, and has spent the last 13 years circling Saturn, probing the ringworld and its remarkable moons. Twenty years ago, it was cocooned up inside its rocket, and hurled into space. No human has seen it since.

This image is one of the last pictures taken of Cassini in 1997, before launch; the whole spacecraft, together with a few of the people who gave it life. Not soon after, the rocket fairing was lowered into place and closed, cocooning Cassini inside. That was the last any human ever saw of it. [Image by NASA]

For more than a decade, we have been treated to remarkable images, ranging from the strange divided faces of Iaepetus, to the mangled surface of small, tumbling Hyperion. We saw stunning views of the blue-white ice of Enceladus, and ephemeral views of Saturn and its rings, backlit by the distant Sun.

The images returned by Cassini have been stunning, and are far too numerous to do justice to here. A few favorites include: Hyperiod (top left), Enceladus (top center), Iapetus (top right), and Saturn backlit by the Sun (lower). [Images by NASA]

But never among these has there been an image of Cassini itself. Unlike its siblings, the Mars rovers, Cassini cannot take a selfie. But our artists have continued to insert Cassini into imagined views of the Saturnian system, seen as if we were sailing along side it, snapping pictures for the family photo album. Cassini cruising over Titan; Cassini plummeting through the ice plumes of Enceladus; Cassini looking back toward a distant blue star that is Earth.

Artist imaginings of Cassini during its decades long exploration of Saturn. [Images by NASA]

Now, after a two decade journey, we are nearing the end. Cassini’s tasks are nearly over. Unlike Pioneer 11 and Voyager 1 and 2, Cassini is bound to Saturn forever; it will not embark on a lonely voyage to the stars, and in fact, it can’t: there simply isn’t enough fuel in its rockets. Instead, the humans who lovingly crafted it and meticulously planned its journey have planned a magnificent send-off. We call it The Grand Finale. The end of the journey is stunning, worthy of an adventurer as bold and brave as Cassini. But we won’t be able to see it, so once again we turn to our artists to illuminate the images in our minds eye.

Some images from Cassini’s Grand Finale. (L) Saturn’s polar regions, up close as Cassini loops over the top of the planet for another ring pass. (C) One of the highest resolution images of the rings ever taken. (R) The small moon Daphnis, carving out a corridor in the rings. [Images by NASA’s Cassini Imaging Team]

In a series of slowly descending orbits, Cassini will voyage closer to Saturn than any spacecraft before. Looping high over the planet, it will plunge down through the rings for the first time, then loop back around and do it again. Over and over again, it will pass through the rings and skim the top of Saturn’s atmosphere. In all, the Grand Finale consists of just more than 22 orbits. On each orbit it dutifully records what it finds, and relays that information back to us here on Earth. Already we have received stupendous views of the rings, of the cloudtops from closer than we’ve ever seen, and the nearby moons framed by a sky simultaneously more majestic and more alien than any we could imagine in a Hollywood studio.

But at the very end, when there is no where else to go, Cassini will finally succumb to the inexorable gravitational pull of Saturn, and be drawn down into the atmosphere. Travelling more than 75,000 miles per hour, it will burn up in a colossal fireball. One of a thousand meteors that might hit Saturn on any day, but this one from a nearby world. We won’t see Cassini. As it falls, it will be linked to Earth only by the tenuous thread of its radio link, faithfully relaying the last of its observations as it sinks forever into the ocean of Saturn’s atmosphere.  At some point, we don’t know when, Cassini will be gone. With no one to see it, Cassini will disintegrate into nothing. Out of our sight, the last of our dreams and aspirations for Cassini will come to an ultimate end.

Will will mourn. But always we will return to the vast photo album we have assembled over its 20 year life. Like a long time friend departing for the other side of the veil of death, we can’t help but be simultaneously overwhelmed by sadness together with admiration for everything that this little robot has accomplished, against all odds. Cassini has forever transformed our understanding of Saturn. Saturn is a real place, as much a part of the story of our solar system and our home as anything we have ever seen.

Once again our artists capture what we cannot see, rendered in NASA’s End of Mission video, using the tools of entertainment to tell us the story of our long departed emissary in it last moments over Saturn. More than any other art or video I’ve seen, they’ve succeeded in evoking how truly huge and majestic Saturn is, and how tiny Cassini is by comparison. All that we know, all that we’ve discovered, we owe to a tiny robot immeasurably dwarfed by the planet it has so faithfully explored.

You owe it to yourself to go watch this video; reflect on all that Cassini is and was, and know that we are capable of doing tremendous things.

Ad astra per aspera. Fare thee well, Cassini.

Improbable, Awesome Pictures

by Shane L. Larson

A friend of mine, who shall remain nameless, was grousing about last month’s enormously successful “Wave at Saturn” campaign.  “WTF? It’s not like Cassini will see any of us in the picture!  People can’t even see Saturn when they’re out waving because the Sun is up!  Why are you going out to wave? You know better!”  Perhaps in a less grumpy-old-man but more conversation-and-education fashion, Sky & Telescope even did a simple analysis to find out if any light from your waving hand actually would have made it onto Cassini’s imaging system (Will Cassini See You?).  I follow this little mathematical exercise perfectly well, and I had made a similar estimate myself.  But I still went outside and waved at Saturn!

I don’t think my friend (or other Grumpy Old Scientists, “GOSes”) understood the point at all, so we had to have a long conversation.  Let’s do the easy one first.  Why did I go out and wave?  Because when I’m a stooped old man who has to have a nurse feed him his Slurpee’s, I didn’t want to look back on my life and regret not going out to wave at Saturn with the rest of humanity. I went out and waved!

Now when I’m 107, I’ll say to my nurse “Did I ever tell you when I was young like you I went out and waved at Saturn?”  He’ll smile at me, pat my arm, and say, “Here Mr. Larson, have another sip of your blue Slurpee.”  I made sure I went and got my certificate from NASA too!  I hope they hang it over my bed in the old folks home. 🙂

My Wave at Saturn certificate. I waved at Saturn!

To address the question of what’s the point, I like to ask a slightly different question: why did people bother to go out and wave at all?  All over the country, people took their kids outside after dinner, or took 15 minutes out of their workday and went out and stood on the sidewalk to wave at a planet 898 million miles away. Why?

Because it is an AWESOME idea.  It sparks a little bit of wonder in the back of your brain to contemplate that the light from every rock, cloud, puddle, car windshield, tree, rooftop, discarded box of macaroni, and waving human hand would travel almost 80 minutes before it arrived at Saturn to be captured by the camera on a robot from another world.  The simple fact that this could even be true should inspire a little bit of pride in every one of us, and make us stand up a little taller.  Only a little more than a century ago, we didn’t even know how to make an airplane fly under its own power.  But today, barely three generations later, our species quite reliably demonstrates the ability to fly beyond the confines of our small world, to send ships sailing the vastness of interplanetary space and send back to us tales of its adventures.

Titan’s surface.

Cryovolcanic Enceladus.

That is AWESOME.  Cassini is only the latest is a long series of emissaries that have been exploring the homeworlds of our solar system, and it has sent us enormous numbers of improbable pictures, not the least of which include pictures from the surface of Titan; images of a blue and white wonderland of the enigmatic moon Enceladus, studded with cryovolcanoes; and of course Saturn itself, bejeweled with its mesmerizing ring system.

Saturn from Cassini.

Saturn hurricane.

For thousands of human generations, Saturn was little more than a point of light in the sky. Galileo’s telescope was so crappy he couldn’t even tell Saturn had a ring; “Saturn has ears,” he wrote.  But today, we can build a self-sufficient robot capable of flying high above Saturn, where it can take pictures of a hurricane large enough to cover half of North America, locked onto the north pole of Saturn inside a mysterious six sided cloud formation called “The Hexagon” (you can’t make this stuff up!).

That is AWESOME.  I think all of us know it is awesome too; that’s why a million people went outside and waved at Saturn.  They were waving at Cassini, our little robot friend who tirelessly circles a world that most of us will never see with our own eyes, uncovering its mysteries and teaching us not just about Saturn, but about ourselves.  Deep down, people understand this, and they want to feel connected to it.  That’s why they all tore themselves away from their Excel spreadsheets, paused in their marketing meetings, left three of the tires off and the oil unchanged in the AMC Pacer, and went outside to join their fellow humans in waving.

The crowd at NASA’s Jet Propulsion Laboratory, waving at Saturn (photo by NASA).

People were so engaged with the activity, they took pictures of themselves waving and posted them to twitter, facebook and instagram.  I get the feeling that they didn’t really care whether Cassini got some light from their furiously waving appendages, but their iPhones did, and they basked in the coolness factor as a result.  Yep, for whatever reason, this geeky, crazy idea to participate in something related to science had some serious street cred.  It was an adventure, and they all participated!

I think every one of us who engages in the profession of science should pay attention to that fact, especially all the GOSes (many of whom aren’t all that old, they’ve just become old in their thought patterns — they probably don’t read blogs, so you should spend some time talking them through this!).  People freely engaged in something related to science. People in vast numbers freely engaged in something related to science. They had fun, they probably learned a little bit (like Saturn is up in the sky, even during the daytime), and walked away with a positive and optimistic view of something that isn’t related to reality TV or Hollywood celebrities.

As scientists, we like to bemoan the state of science literacy in the world today, a malaise that is driven by the very vocal anti-science rhetoric that has become inextricably entwined with politics.  There are climate-change deniers and anti-vaxxers to be sure, but when I see a million people standing out on a sunny Earth afternoon waving at a camera improbably far away, I have a little hope.

And to top it all off, we’re still getting payback from the event!  NASA released Casssini’s snapshot of us all to great fanfare.  Here it is.

The Earth, seen from Saturn.

See that little dot, lost in the blackness below the majestic arc of Saturn’s ring?  That’s us; that’s home.  You’re in that picture, waving. Your mother is in that picture, waving. I’m in that picture, waving.  Every human being, waving or not, is in that picture.  At the moment this picture was snapped, we were all paying attention.  An improbable moment, captured for all time by a little robot with an improbable mission: seek out new things, learn all you can, and return that information to your creators.

That is AWESOME.

Take some time tonight, and before you fold up your laptop, take a moment to sift through some of the pictures from Cassini.  Take a look at the pictures you snapped during Wave at Saturn, and the ones that Cassini sent back, and remember how engaged the world was with this activity.  Improbable pictures, improbable engagement, but a stunning success.

Well played, NASA.  Well played.  Now let’s do it again.