Lowell astronomers to help lead Pluto-Kuiper mission
Posted: January 6, 2002

Two Lowell Observatory astronomers are members of the New Horizons science team selected by NASA to lead the Pluto-Kuiper Belt mission, intended to explore our solar system's most distant planet and beyond.

John Spencer and Will Grundy, both experts on the compositions and physical behaviors of icy solar system surfaces, are responsible for producing and interpreting surface composition and temperature maps of Pluto and its moon, Charon, from data gathered from the mission. In addition, they will work to ensure that the spacecraft's instrumentation, when launched, is optimized to probe the surface and atmosphere of Pluto and Charon.

An artist's concept of the New Horizons spacecraft. The craft's miniature cameras, radio science experiment, ultraviolet and infrared spectrometers and space plasma experiments will characterize the global geology and geomorphology of Pluto and Charon, map their surface compositions and temperatures, and examine Pluto's atmosphere in detail. The spacecraft's most prominent design feature is an 8-foot dish antenna, through which it will communicate with Earth from as far as 4.7 billion miles away. Photo: Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute (JHUAPL/SwRI)
"This is an exciting time in astronomy," Grundy says. "Our ability to answer fundamental questions about the surface properties, geological and interior makeup, and atmospheric conditions of Pluto, Charon and Kuiper Belt Objects will propel science into new and exciting frontiers, unraveling some of our solar system's greatest mysteries."

The mission, called New Horizons: Shedding Light on Frontier Worlds,seeks to answer questions about the surfaces, atmospheres, interiors and space environments of the outermost objects in our solar system. The spacecraft first explores Pluto and its moon, Charon. It then journeys beyond Pluto to visit one or more Kuiper Belt Objects -- small, icy objects beyond Neptune's orbit believed to be a source of Earth's water and the simple chemical precursors of life. Set to launch in 2006, the spacecraft will fly past Pluto and Charon in 2016 and then venture into the Kuiper Belt.

Spencer and Grundy will help choreograph the spacecraft's close flyby of Pluto and Charon in 2016. From data gathered, they will be able to map the surfaces of both Pluto and Charon, and determine the location, temperatures, and kinds of ices on each. Pluto's surface is so cold that gases such as nitrogen, methane and carbon dioxide partly freeze solid, resulting in a strange, alien landscape.

"Given Lowell Observatory's long history studying the Pluto-Charon system and the Kuiper Belt, I'm proud that John Spencer and Will Grundy are involved in this important mission," says Dr. Robert Millis, director of Lowell Observatory.

Clyde Tombaugh discovered Pluto at Lowell Observatory in 1930. Today many Lowell astronomers continue to study the ninth planet. In addition, Lowell Observatory astronomers actively explore the Kuiper Belt, the area beyond Neptune's orbit where Kuiper Belt Objects reside.

"More than 500 Kuiper Belt Objects have been discovered since the first one was found in 1992," Grundy says. "But this number represents only a tiny fraction of the objects expected to exist in that distant region of the solar system."

To explore the uncharted area beyond Pluto, the spacecraft will retarget itself after visiting Pluto for encounters with one or more Kuiper Belt Objects, hopefully one that is at least 50-100 kilometers across. Specific target objects have not been identified yet, but are anticipated to be irregularly shaped and about 50-100 kilometers across.

"Lowell astronomers will point their telescopes along the future spacecraft track in an effort to find suitable Kuiper Belt Objects for the spacecraft to visit," Spencer says. This is no easy task, says Grundy, because these objects are so faint, making them incredibly difficult to detect.

Lowell Observatory's Deep Ecliptic Survey, headed by Millis, has found more Kuiper Belt Objects than any other program. When the time comes, the techniques developed by the Observatory's survey team are likely to find several well-positioned objects for the spacecraft to target.

During its 20-year adventure, the spacecraft will gather data and images using visible-wavelength cameras, infrared and UV spectrometers, radio waves, and more. Using this information, scientists will be able to answer important questions about these previously unexplored celestial bodies.

"Pluto and the Kuiper Belt comprise the unexplored frontier of the solar system, and hold many secrets about how the solar system, and thus humanity itself, came into being," Spencer says. "New Horizons will help us to unlock these secrets."

After years of reviewing mission proposals, NASA on Nov. 29 selected the New Horizons team to lead the Pluto-Kuiper Belt mission. The team is lead by Principal Investigator Dr. S. Alan Stern of the Southwest Research Institute in Boulder, Colo. The team also includes members from the John Hopkins University Applied Physics Lab, Laurel, Md., Ball Aerospace Corp., Boulder, Colo., Stanford University, Palo Alto, Calif., and NASA's Goddard Space Flight Center, Grennbelt, Md., and Jet Propulsion Laboratory, Pasadena, Calif.

About Will Grundy
Will Grundy joined Lowell Observatory's staff in 1997 as a Hubble Postdoctoral Fellow. As a leading expert in the remote sensing of icy and organic materials in the outer solar system, Grundy has made state-of-the art contributions both in laboratory studies of cryogenic ices and in the modeling of Pluto and Charon, icy satellite spectra and Kuiper Belt Objects. He is widely recognized for developing sophisticated techniques for retrieving information about temperatures and textures of outer solar system ices. For the Pluto-Kuiper Belt mission, Grundy serves on the Surface Composition team, and is directly responsible for producing composition and temperature maps from data gathered by the spacecraft. In addition, he works to ensure that the spacecraft's instrumentation is capable of successfully probing the surface and atmosphere of Pluto and Charon. Grundy earned his doctorate in planetary sciences from the University of Arizona in 1995.

About John Spencer
John Spencer joined the Lowell Observatory staff in 1991, and has been involved in planning for the Pluto mission since 1993. A recognized expert on the small bodies of the outer solar system, he uses data from telescopes and interplanetary spacecraft to understand the temperatures and compositions of these distant worlds and has a particular interest in the seasonal migration of frosts on Pluto. He is a member of the Galileo Jupiter Orbiter science team, studying Jupiter's moons with the Photopolarimeter/Radiometer (PPR) instrument, and is a science-team associate on the Cassini Saturn Orbiter mission. He is also a frequent user of the Hubble Space Telescope. On the New Horizons mission, he is responsible for using images and spectra of Pluto to map surface temperatures and understand how frost on Pluto's surface evaporates to generate Pluto's atmosphere. He will be working with the rest of the team to make sure that the spacecraft's instruments and observations are optimized for this task. Spencer earned his doctorate in planetary sciences from the University of Arizona in 1987.

About Lowell Observatory
Lowell Observatory is a private, non-profit institution dedicated to astronomical research. In addition to studying the Pluto-Charon system and the Kuiper Belt, Lowell astronomers also explore comets, Near-Earth asteroids, the sun, planetary rings, and more. The Observatory also educates more than 70,000 people about astronomy each year through its extensive public outreach programs. Founded in 1894, Lowell Observatory has a staff of 55, including 20 Ph.D. astronomers. Lowell operates from a 740-acre forested campus on Mars Hill, overlooking Flagstaff, Arizona.