Category Archives: Pluto

What Would Clyde Think?

Five years ago, the world paused for a moment to admire the view of a distant world called Pluto. Its discoverer, Clyde Tombaugh wasn’t around to see the spectacular New Horizons views of the planet he discovered in 1930. But, in another sense, he WAS there with the rest of us.

Pluto's colorful surface. Pluto was discovered by Clyde Tombaugh in 1930 and explored by New Horizons in 2015.
Pluto’s colorful surface units show different compositions and terrains. Courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

A few grams of Clyde’s ashes fly on the New Horizons spacecraft that flew by his planet. So, for a collective moment, we explored Pluto with its discoverer and the team of scientists he inspired.

The late Clyde Tombaugh, discoverer of Pluto. courtesy NMSU.
The late Clyde Tombaugh in 1989. He died in 1997 at age 90,. Courtesy NMSU.

I’ve often wondered what Clyde would think of Pluto, up-close, and personal. I only met him a few times. He was a man with a great sense of humor and humility about his accomplishment. So, I imagine that he’d love it all. It would have been cool to have him on the science team as New Horizons flew by. His family members attended the flyby festivities in mid-July 2015 and celebrated the mission.


A Virtual Pluto Celebration

Today, we are in a very different world, one where a pandemic has closed us off to social gatherings like the one we all experienced at “mission control” at Johns Hopkins Applied Physics lab half a decade ago. Instead of meeting to talk over old times at Pluto, now we have to do it virtually.

So, instead, let’s imagine a circle of scientists sitting here with us. They’re reminiscing about the amazing mission to Clyde’s world. I asked a collection of New Horizons researchers to do exactly that. What did they learn about Pluto? If they could take Clyde on a guided tour, what would they show and tell him about Pluto?

Show and Tell for Clyde

Obviously, the first thing to show him would be heart-shaped Tombaugh Regio area of Pluto. It became THE ‘iconic’ view of the planet from the beginning of the flyby. That image changed forever how we saw that distant planet. Its icy terrain and lobe-shaped Sputnik Planitia section show glaciers butting up against mountains of water ice. Those features would likely excite Clyde. Those who knew him would be expecting him to crack a few puns to celebrate the occasion.

Mountains on Pluto
This image shows the inset in context next to a larger view that covers most of Pluto’s encounter hemisphere. The inset was obtained by the Multispectral Visible Imaging Camera (MVIC) instrument on New Horizons. North is up; illumination is from the top-left of the image. The image resolution is about 1050 feet (320 meters) per pixel. The image measures a little over 300 miles (almost 500 kilometers) long and about 210 miles (340 kilometers) wide. It was obtained at a range of approximately 9,950 miles (16,000 kilometers) from Pluto, about 12 minutes before New Horizons’ closest approach to Pluto on July 14, 2015. Courtesy NASA/JHU-APL, SWRI/New Horizons mission.

But, he might also be touched by other views. The most telling and effective image of Pluto is a view of its atmosphere and surface together. It encapsulated the planet, its atmosphere, and a feeling.

Pluto's mountains, plains, and layered hazy atmosphere.

For Anne Verbiscer, a member of the New Horizons team, that’s the view she would share with him. “I’d show him that image taken at twilight,” she said. “I was reduced to tears when I saw it. I’ve had the same reaction to only one other planetary image returned by a spacecraft…it was the first image of Enceladus taken by Cassini for which I had done the “commanding”. Enceladus was in eclipse (behind Saturn), so I had very little information to use to set the exposure time correctly. I was sure that the image would either be black or over-exposed. When that image arrived on the ground, I saw that it was perfect, and yes, I sobbed, just like I did when I saw Clyde’s amazing world in all its glory on that September weekend in 2015.”

That view reminds all of us of the strange beauty of planetary exploration. There’s always something new to be seen, and when the exploration ends, there’s much to learn from the data collected. “I would show Clyde that image of Pluto at twilight (the one with the bottom of Sputnik Planitia in the foreground, the mountains rising above the limb, and the hazes above the horizon)….. and just drop the mic,” said Anne.

Clyde’s Surprising World

Principal investigator Alan Stern, not often at a loss for words, finds it hard to say what surprised him most about Pluto. “Before the flyby I might have not been surprised to find one of these: an interior ocean, or blue skies, or bladed mountains, or vast glaciers, or cryovolcanoes, or a paleolake,” he said. “But we found them all! And that is the most surprising aspect to me. That is, just how incredibly complex and diverse and frankly amazing as a scientific wonderland that Pluto turned out to be.”

To give you an idea of what amazed Alan and the others, take a look back in time. Clyde’s view in 1930 was of a small dot. That’s about all any of us can see, even with the best ground-based telescopes Even a high-resolution Hubble Space Telescope view showed a bland surface with a few bright and dark areas. No details of what was to come.

A Surprising World

New Horizons showed that every region on Pluto has something different on it, with some features unique to that world alone. Five years later, after much study and analysis, all that geology tells us something we didn’t know about the planet before the spacecraft went by: it’s not a dead world. “It shows the action of a wide range of planetary processes,” said Hal Weaver, another team member and long time planetary scientist. “That includes some that happened long ago, and others indicating ongoing activity into the current epoch.”

A closeup of the highlands on the edge of  Sputnik Planum. There are also ice pits and other features indicating some kind of geologic activity in the past and possibly in the present.  Courtesy  NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
A closeup of the highlands on the edge of Sputnik Planum. There are also ice pits and other features indicating some kind of geologic activity in the past and possibly in the present. Courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

In other words, Pluto is alive. That’s a surprise, even today. And, that’s what Hal would tell Clyde first. If he could go to Pluto on a guided tour, the first place Hal would land would be Sputnik Planitia. “It’s responsible for Pluto’s “mojo”,” he says. “Especially its periphery. And, it’s part of the region named for Clyde! And, I’d bring along his extended family, too!”

Pluto and the followup mission to Arrokoth have accomplished another amazing feat. Those flybys prove the outer solar system isn’t what people expected it to be. “Pluto and Arrokoth have showed us that the Kuiper Belt is so full of surprises and revelations about the formation and evolution of the solar system,” said Paul Schenk, of the Lunar and Planetary Institute in Houston. “Going back to the Belt should be a high priority, to look at small, medium, and large-sized bodies and find out what happened there in the early days of our solar neighborhood.”

Beyond Clyde’s World

Nowadays, New Horizons is far beyond the Plutonian system. A few years ago, it explored Arrokoth, which is another Kuiper Belt object. It has other tasks ahead of it, including possible visits to new worlds. Its story is really one of opening the exploration of the third regime of the solar system. We’ve explored the inner solar system, the “middle” solar system of the gas and ice giants, and now the distant regime is open to our view.

Indeed, the exploration of the outer solar system really began with this mission. It is the first spacecraft to give us a true “up close and personal” look at the Kuiper Belt neighborhood. It’s only fitting that another spacecraft should make its way out there, to follow up on what New Horizons started.

Team member Kelsi Singer pointed out that there would be much to explore. “If we could go back with a spacecraft that orbits Pluto [instead of flying by], we could learn if Pluto has an ocean beneath its icy shell,” she said. “We could also further investigate how all its unique features formed. Of course, a lander or rover would be fabulous, but we have much to learn from an orbiter, first.”

Celebrating a Milestone with Clyde

Pluto and its exploration five years ago sparked our imaginations. It opened our eyes to an alien world. And, it shows us that preconceptions about planets are meant to be shattered. If New Horizons does nothing else, it will have shown us to expect the unexpected at every turn.

Alan Stern, who waited many long years for that exploration, working with some of the best scientists in the solar system, would just as soon be out there in an orbiter right now. He and a continuing team of scientists want to follow the trail that their spacecraft blazed.

And, if he could take Clyde along with him on that trip, he would. “I’d tell Clyde, who I knew, that he discovered an amazing world that has literally revolutionized our knowledge of planetary science in multiple important ways, and that in my view, we now know that in Pluto, the solar system saved the best for last!”

The backlit view of Pluto as New Horizons ‘waved’ a last good bye. NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Chasing New Horizons

The Spacecraft Is Doing Well

Every week, the New Horizons spacecraft sends back a little signal that it’s still alive and kicking, even as it snoozes its way toward its next target. It’s a “green light” signal and every time it shows up, the NH team, as well as its fans around the world, breathe easy. They know that all’s well out in the Kuiper Belt. Later this year, New Horizons will ‘wake up’ and start operations for the next target. It’s on the way out to Ultima Thule, the next (and probably final) flyby on its tour of the Belt. That’ll happen on the last day of December into January 1, 2019. We’re all hoping the data return will be spectacular.

Reading Up on the Mission

chasing new horizons
Chasing New Horizons is a new book about the Pluto mission and its backstory. Courtesy Picador Books.

The story of New Horizons has played out in the public eye ever since the first of the “best images” of Pluto made it back from the spacecraft in 2015. However, the human side of the New Horizons mission is a lesser-known story.  That’s all about to change with the release on May 1st of the book Chasing New Horizons: Inside the Epic First Mission to Pluto, written by the mission’s principal investigator Alan Stern and planetary scientist/science writer David Grinspoon.

I have read the book twice now thanks to the publisher who sent me a lovely review copy. It’s a thought-provoking and well-written story of the behind-the-scenes action that brought the spacecraft to life. Now, I should mention (by way of transparency) that Alan and David and I all worked in the same lab at the University of Colorado, during overlapping residencies in the late 1980s and 1990s. I know several other team members, including Fran Bagenal, who was one of my professors at CU and a friend. So, reading the story and knowing the folks who were involved lent a much more personal air to their experiences.

Even though I knew that Alan was interested in icy, frozen worlds, I really didn’t know much about how he and his team worked. They embarked on a quarter century of effort. That got their mission taken seriously by NASA, funded, flown, and out to its targets. Reading Chasing New Horizons really opened my eyes to the skull sweat, imagination, and determination it takes to get something like New Horizons “on the road”. Despite being thrown many an obstacle, both technological and political, Stern and the team got it done, and the book is a wonderful testament to their work.

Loss of Signal

Chasing New Horizons presents a lot of insight into what it’s like to be on a spacecraft mission. Those revelations delighted me to no end. For one thing, I always thought it would be cool to work on a mission like this. That was one of my goals when I went back to grad school. I did end up working on a mission team, but for Hubble Space Telescope. That, too, had its challenges, as most people remember. Despite its many problems, HST soldiers on, as do its team members around the world.

For New Horizons team members, there were also heart-stopping moments like those we faced with spherical aberration. Just six days before the Pluto flyby, New Horizons ceased communications. It happened right after an upload of software commands and sent everyone into high gear to solve the problem. In the book, mission operations manager Alice Bowman described the moment when NH went dark.

“You know that feeling in the pit of your stomach when something is occurring, and you can’t believe it’s happening? We’d come nine and a half years on this journey, and I couldn’t believe this—we’d never lost communications. You allow yourself that five, ten seconds of feeling that fear and disbelief, but then everything we trained for started to kick in.”

In the post-launch chapters in Chasing New Horizons, Alan and David describe the constant training and practice runs the team engaged in to face situations just like this one. Within minutes of signal loss, the people began to diagnose the problem and figure out a solution. And, fix it they did. As we all know, the mission went on as planned, delivering magnificent results.

The Personal Becomes the Public

Chasing New Horizons is filled with personal,  technological, and scientific insights on a very public mission. The writers interviewed team members and shared their comments to flesh out the not-so-public portion of the mission. There are some incredible scenes that just sent a chill through me as I realized that I knew the people to which these things were happening.

Even if you don’t know Alan Stern and Alice Bowman and Glen Fountain and Fran Bagenal and others who guided the spacecraft from birth to Pluto and beyond, you’ll get a thrill reading their stories. The book belongs on your bookshelf. Read it often. Appreciate what it is our fellow citizens have done to bring Pluto and the Kuiper Belt into our view.