The main goal of NASA's New Horizons mission may be to explore Pluto-Charon and the Kuiper belt beginning in 2015, but first the mission plans to fly by the solar system's largest planet, Jupiter, during February-March 2007. The Jupiter flyby would be used by New Horizons to provide a gravitational assist that shaves years off the trip time to Pluto-Charon and the Kuiper belt.

In this artist's concept, New Horizons is just past its closest approach to Jupiter in 2007. Near the Sun are Earth, Venus and Mercury. The dim crescent shape upper right of the Sun is Callisto, the outermost of Jupiter's four largest moons. Just left of Jupiter is Europa. Credit: Dan Durda, SwRI Boulder

During the flyby, plans call for New Horizons to use its instrument payload, consisting of cameras, spectrometers, radiometers, and space plasma and dust sensors, to make a variety of scientific observations. Toward that end, the New Horizons team has formally kicked off its planning of the Jupiter flyby science observations. Southwest Research Institute (SwRI) and the Johns Hopkins University Applied Physics Laboratory (APL) lead the mission. Major partners include Ball Aerospace, Lockheed-Martin, Boeing, NASA Goddard Space Flight Center and the California Institute of Technology Jet Propulsion Laboratory.

"Every spacecraft must check out its instruments and pointing capabilities in flight prior to reaching its target," says mission project scientist Dr. Hal Weaver of the Johns Hopkins University Applied Physics Laboratory. "By virtue of the gravity assist maneuver at Jupiter, New Horizons has a unique opportunity to do its check out on a very worthy and exciting scientific target."

"New Horizons presents NASA's next opportunity to study the complex and fascinating Jupiter system," says Dr. Alan Stern, principal investigator of the New Horizons mission and director of the SwRI Space Studies Department. "To accomplish its gravity-assist maneuver on the way to Pluto-Charon, our spacecraft will venture at least three times closer to Jupiter than the Cassini spacecraft did in late 2000 when it used Jupiter for a gravity assist on the way to Saturn.

"Astronomically speaking, we will fly just outside of the edge of Jupiter's large, planet-sized Galilean moon, Callisto." From its closer range, New Horizons will perform a number of Jupiter system studies not possible from Cassini's greater flyby distance.

Science planning is going forward to ready the mission for its planned 2006 launch, at the same time that required environmental and safety reviews are also being done. Through the summer of 2004, the New Horizons science team will prioritize its Jupiter science activities from objectives provided by team members as well as interested scientists from around the world. To accomplish this objective, Stern has appointed mission co-investigator and imaging team lead Dr. Jeff Moore of the NASA Ames Research Center to lead the New Horizons Jupiter Encounter Sequencing Team (JEST).

"New Horizons will be the next mission to Jupiter, and it is carrying a sophisticated instrument complement," says Moore. "We intend to cull and then schedule the most critical needs for scientific observations of Jupiter, its satellites, its magnetosphere and its rings.

"Following that," Moore continued, "the mission team will design and implement a five-month-long sequence of observations of the Jupiter system to be made from late 2006 through early 2007 as the spacecraft approaches and then recedes from Jupiter."

"Exploring the Jupiter system is a coveted scientific bonus for New Horizons," adds Weaver. "It also provides us with a valuable opportunity to check out the instrument payload and many of the flyby procedures we will later use at Pluto-Charon."

New Horizons is proceeding toward a January 2006 launch, with a planned arrival at Pluto and its moon, Charon, in the summer of 2015. The 465-kilogram (1,025-pound) spacecraft will characterize the global geology and geomorphology of Pluto and Charon, map the surface compositions and temperatures of these worlds, and study Pluto's atmospheric composition and structure. It will then visit one or more of the icy, primordial bodies in the Kuiper belt where it will make similar investigations.

In July 2002, the National Research Council's Decadal Survey for Planetary Science ranked the reconnaissance of Pluto-Charon and the Kuiper belt as its highest priority for a new start mission in planetary science, citing the fundamental scientific importance of these bodies to advancing understanding of our solar system.

SwRI is an independent, nonprofit, applied research and development organization based in San Antonio, Texas, with more than 2,800 employees and an annual research volume of more than $339 million.