Christmas in July


by Mary Blake

Dr. Alan Stern of the Southwest Research Institute in Boulder, Colo., waited a long time for the New Horizons spacecraft to fly by Pluto on July 14, 2015. He has worked on this project in one form or another for 26 years.  And the wait was worth it for the New Horizon Mission’s Principal Investigator (PI) who marveled at the image of Pluto’s atmosphere backlit by the sun.

The New Horizons spacecraft launches aboard an Atlas V rocket January 19, 2006

“My jaw was on the ground when I saw this first image of an alien atmosphere in the Kuiper Belt,” he said. “It reminds us that exploration brings us more than just incredible discoveries — it brings incredible beauty.”

Pluto's hazy atmosphere. Credit NASAPluto has turned out to be a treasure trove of exotic surface chemistry, flowing ices, mountain ranges, icy plains and a vast, 2- layered  haze as high as 80 miles above the planet’s surface. A giant surprise was a range of youthful mountains nearly as high as Colorado’s Rocky Mountains, indicating that Pluto may be geologically active. 

New compositional data from Ball’s Ralph camera shows details about the Texas-sized plain named Sputnik Planum inside the western part of the heart-shaped feature named Tombaugh Regio. The center of Sputnik Planum is rich in nitrogen, carbon monoxide, and methane ices. And there is much more to come as New Horizons’ flyby data is downloaded and analyzed over the next year. 

NASA’s $720 million New Horizon’s Pluto-Kuiper Belt mission is the largest ever PI-led space mission launched by the agency.  Dr. Stern is also the PI of two of the seven instruments aboard New Horizons: the Alice Ultraviolet spectrometer and the Ball Aerospace-built Ralph Visible Imager/Infrared Spectrometer. Ralph and Alice are a nod to the 50s classic TV series “The Honeymooners.” 


Up close and personal 

After traveling for over nine years to the edge of our solar system, New Horizons has uncovered Pluto’s mysteries. The Ralph instrument played a big role in the encounter, providing most of the color images and global composition mapping of Pluto and its largest moon, Charon. The New Horizons spacecraft came within 12,500 km (7,767 miles) of Pluto traveling at over 31,000 miles per hour.

Dr. Alan Stern. Credit NASA/Bill Ingalls
"Ralph is the New Horizons mission's main sense of sight," Stern explains.  "Among other things, Ralph made maps that show us what Pluto, Charon and Kuiper Belt objects look like. And Pluto is so far from the Sun that Ralph accomplished this at light levels 1,000 times fainter than daylight at Earth.”

Ralph includes the Multispectral Visible Imaging Camera (MVIC) and the Linear Etalon Imaging Spectral Array (LEISA), provided by NASA/Goddard. Ralph characterized the global geology and topography of Pluto and its large moon, Charon, mapped their surface compositions and temperatures, examined Pluto’s atmospheric composition and structure, studied Pluto’s smaller moons and searched for new moons and rings. 

Ralph imaged the dwarf planet with a suite of detectors fed by a three-mirror telescope with a resolution 10 times higher than the human eye. Small but powerful, Ralph weighs only 23 pounds and uses only about seven watts, the power of a standard night light.  The entire telescope operates around 220 K (-60° F) in the cold darkness of the outer solar system.

Because Ralph had to travel nearly 10 years and 2.9 billion miles through the harshness of space, it was made to last. The Ball team used very tough, very light components that use little energy and don’t produce a lot of heat. In space, the temperature fluctuates, making materials shrink and expand. Ralph was made out of aluminum so all its parts would change shape at the same rate. In addition, Ralph has to be able to image at very low light levels because high noon on Pluto is about as bright as dusk on Earth. 

“We had to design a telescope lens to work in that kind of condition,” said Ball’s New Horizons Program Manager Lisa Hardaway. “So we added a hinged lens cover – Ralph’s only moving part.”

Ralph’s companion instrument, Alice, is a compact, general-purpose UV imaging telescope spectrometer. Its purpose is to probe the atmospheric composition of Pluto. A spectrometer separates light into its principal wavelengths, like a prism, only better. An imaging spectrometer both separates the different wavelengths of light and produces an image of the target at each wavelength. 

Making history 

What makes the New Horizons Mission so significant is that it has been such a long time since the United States has been involved in first-time exploration. The last time was in the late 1980s with Voyager. There’s a whole generation of people who have never experienced an event this historic. 

 “The United States has been first to every planet in the solar system. In the history of spaceflight, nobody else has even attempted flight out to the giant planets, much less the Kuiper Belt,” said Stern.

Pluto is a dwarf planet with a complex system of moons that has been explored for the first time by the New Horizons spacecraft. The planet is the farthest from the sun in our solar system, some 3.6 billion miles out in what scientists call the third zone or the Kuiper Belt, a plane of icy, rocky remnants left over from when our solar system was formed.  

“We’re finding a tremendous variety of planets relative to what we knew when all we could see was a few billion miles across our own solar system,” said Stern.  “And as technology has allowed us to probe around other stars, and at the same time deeper into our solar system, our old preconceived notions have been swept away. Not many solar systems look like ours and not many planets look like ours.” 

Hubble/ New Horizons connections

Even before the launch of New Horizons in 2006, the Hubble Space Telescope with five optical science instruments on board built by Ball, has provided consistent support for this edge-of-the-solar system mission. Hubble was used to discover four small moons orbiting Pluto and its moon Charon, providing new targets to enhance the mission’s scientific return. Hubble also has made a detailed map of the dwarf planet's surface, which astronomers used to plan New Horizon's close-up reconnaissance photos.

The New Horizons spacecraft is equipped to collect data 100 times faster than it can send it home. The process of sending the uncompressed images and data back to Earth will take 16 months. 

Showered with awards 

The mission has been so successful that the New Horizons team received the National Space Club’s highest honor, the 2016 Dr. Robert H. Goddard Memorial Trophy. It was presented at the 59th Annual Robert H. Goddard Memorial Dinner on Friday, March 11. 

The New Horizons missions also won a prestigious Aviation Week Laureate Award in the Space category and the American Astronautical Society has presented Dr. Stern with the Carl Sagan award for “demonstrated leadership in research or policies advancing exploration of the cosmos." The Society also honored the New Horizons team with the 2015 Neil Armstrong Space Flight Achievement Award for outstanding achievement as a flight crew. 

New Horizons also earned the No. 1 spots in both the Discover Magazine Top 100 Stories of 2015 and the Science News magazine Top 25 Science Stories of 2015.

The Ralph/MVIC cameras amplify the subtle shade difference on Pluto's surface. Credit NASA

What’s next?

As part of an extended mission, pending NASA approval, the spacecraft is expected to head farther into the Kuiper Belt to examine an ancient building block of small planets like Pluto on January 1, 2019, located more than a billion miles beyond Pluto.

Ralph is a joint project of Southwest Research Institute (SwRI), Ball Aerospace and NASA's Goddard Space Flight Center.  The Applied Physics Laboratory at Johns Hopkins University built and operates the New Horizons spacecraft and manages the mission for NASA. 

Pluto's Close-Up

Learn about the stunning clarity of Pluto’s features that Ball’s Ralph camera is showing us.

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