Fairfax Station About a decade ago, the public found out that Pluto was no longer considered one of the nine major planets in the solar system. In 2006, the International Astronomical Union demoted the small planet, the furthest of the nine away from the sun, to “dwarf planet” status, citing Pluto’s size and location as the reason for its revised status.
Clifton scientist Dr. Michael Summers, also a professor of Planetary Science and Astronomy at George Mason University, said he still considers Pluto one of the nine major planets in the solar system. One of the foremost experts on Pluto, Summers is part of the New Horizon mission team, which has spent the last decade designing, preparing and maneuvering a space probe for the first ever close-up observation of Pluto.
“In its basic form, a space probe is an independent robotic vehicle carrying a set of instruments that is launched via high power rocket into deep space,” Summers said. “It communicates with ground control by radio communications. Typically, a spacecraft has onboard computers controlling activities, but its activities can be controlled by scientists on Earth if that is needed.”
SUMMERS’ ROLE on the mission team is far from over, despite the probe’s having passed by Pluto last year.
“My role on the team has been in planning and carrying out atmospheric science observations and analysis,” he said. “Pluto has a very complex atmosphere, much more complex and difficult to understand than we expected. So I spent many of the early years helping to plan the atmospheric science observations, then years of modeling Pluto’s atmosphere in order to make baseline predictions for the team. After the launch we had to put together a detailed encounter plan. Throughout this mission I’ve been the Deputy Lead of the Atmospheric Science Theme Team.”
Summers and his 23 other team members launched the probe from Cape Canaveral on Jan. 19, 2006. However, it didn’t reach fly by Pluto until nearly a decade later. The length of the mission speaks to how far away Pluto is from Earth, especially considering that New Horizons was launched at a speed of 38,000 miles per hour.
“By the time I flew home to Clifton from Cape Canaveral after the launch, the probe had passed the orbit of the moon,” Summers recalled. “A month later, it had passed Mars’ orbit, so that gives you an idea just how far away Pluto really is. We were actually able to cut the time of the trip by directing the spacecraft to a close flyby of the planet Jupiter in February 2007. We used Jupiter’s gravity to slingshot the spacecraft, speeding it up, but, even so, it took us until July 14, 2015 to get to Pluto. And, New Horizons was the fastest spacecraft ever launched from Earth.”
In the time it took the probe to reach Pluto’s orbit, two members of the original team died, and a couple others moved on to different positions. Still, Pluto’s distance wasn’t the only factor that made the mission so complicated.
“There are actually numerous space probes, called satellites, in Earth’s orbit that operate pretty much the same way as New Horizons,” Summer said, “but deep space missions are much, much more difficult for many reasons. Just one example is the time delay for communication. For the New Horizons spacecraft at Pluto, the time delay for radio signals to get to Earth was about four and a half hours. So any signal sent from the spacecraft took that long to get to us to let us know what was going on with the mission.”
The New Horizons mission provided the first images of Pluto that humans had ever seen — resulting in groundbreaking discoveries that refuted previous assumptions about Pluto’s terrain, atmosphere, interior, and its five moons.
“We were incredibly surprised to see what we did see on Pluto,” Summers said. “We expected it to be cold and dead — much like the Earth’s moon — but it really was a geologically active and diverse place.”
He added that while the other eight planets are categorized into two classes — terrestrial and gas giants — Pluto, as a dwarf ice planet, is in a third class of its own.
While it’s still impossible to conclude anything about living creatures on Pluto, Summers said that Pluto certainly contains enough natural resources to support life.
“We’re finding out that many of the most interesting places in the solar system are out there in the region of Pluto’s orbit,” he said. “There are 100,000 objects like Pluto, called Kuiper Belt objects, in that region of our solar system. We know they exist, and that they have enormous amounts of water and other resources. Utilizing all those resources will be crucial for the future of humanity’s exploration of deep space. We found that Pluto has an ocean of water below an ice crust that we think is about six miles thick. There may be more liquid water inside Pluto than in all of Earth’s oceans combined. And, of course, there has to be the energy inside Pluto to keep all that water in liquid form. Energy, raw materials and liquid water are all required for life, and Pluto has plenty of them.”
THE SMALL SIZE of Pluto, with a diameter less than 20 percent of Earth’s, does not mean that Pluto is in any way less interesting as a planet.
“There have been so many discoveries, it’s almost exhausting to see something new every time we study the observations,” he said. “We are having to rewrite planetary textbooks, and write the first books ever on dwarf ice planets. What we learn doesn’t just help us understand Pluto, it also helps us understand the other planets and even the Earth. The New Horizons mission changed how we think about the solar system. We’ve even found dried up lakes on the surface of Pluto and evidence of climate change. It’s a very complicated world out there.”
While experts sift through all the discoveries, the New Horizons spacecraft continues to work for its creators. The National Aeronautics and Space Administration (NASA) approved a detour for the space probe to check out a neighbor, relatively speaking, of Pluto.
“We are flying by another dwarf ice planet in about two years from now,” Summers said. “It’s a complete bonus. We knew it was a possibility, but the spacecraft is completely healthy and has plenty of fuel and energy on board, so we decided to propose to NASA to continue the mission and fly by another dwarf planet that was near the spacecraft’s trajectory. It will reach that body on New Year’s Day, 2019. What we know is that this object very small and may be more rocky and metallic than Pluto. We don’t know whether or not it has an atmosphere.”
Summers was studying Pluto long before New Horizons first began its journey more than a decade ago. He began his research on Pluto in graduate school at Caltech in 1982, and, in the late 1990s, he and his fellow future New Horizons mission colleagues began planning for a Pluto mission to propose to NASA. And, long before he studied the solar system in any official capacity, Summers was just a boy in western Kentucky whose interest in outer space piqued during America’s space race with Russia.
“I’ve been interested in space since I was 7 years old when my parents gave me my first telescope,” he said. “I was able to see four of the major planets even with such a small telescope, including Saturn with its rings, so that hooked me on astronomy.”
In addition to conducting his own research on Pluto, he also works with George Mason University students who are doing research about the planet.
ADAM JACOBS, a Ph.D. student in physics and also Summers’ research assistant, said that Summers has certainly influenced his course of study.
“Dr. Summers is my dissertation research advisor,” Jacobs said. “Working with him is definitely a privilege. As a young scientist, it is critical that you get guidance and advice from an experienced scientist that not only knows their stuff but also is approachable and great at communicating ideas and goals. I found this with him. The other interesting thing that I get to be exposed to is the work dynamic and pace of a NASA science team. When the New Horizons data started coming, the culmination of so much hard work, patience, frustration, and entire careers even, started to come together. I’m not part of the team, but being able to witness just glimpses of that is exciting and a testament to the modern scientific process.”
Jacobs said that although he may not end up devoting his career to planetary sciences specifically, he said it quickly became obvious to him how incredibly important it is for the government and experts to pursue planetary research.
“When the New Horizons spacecraft finally reached Pluto, huge amounts of data started being beamed back to Earth,” he said. “We’re now starting to form the right questions so that we can understand how planetary atmospheres behave in general, including Earth's atmosphere and climate.”
Summers has spent more than 30 years poring over Pluto, and his work is nowhere near done. The years that Summers and his colleagues have devoted to Pluto have produced just as many questions as it has conclusions.
“Many Pluto mysteries that came out of this mission,” Summers said. “For example, what is the internal heat source? There must be an energy source that we just haven’t identified. Elements of the atmosphere out there were much more unusual than we expected, and there were just so many things we’d never seen before. Recently, we finally got all the data back from the spacecraft, and I can tell you that we will be studying this information for years. Hundreds of scientific papers will come out of this mission. It’s a scientific bonanza in a way.”