NASA has selected a proposal to proceed with Phase B
(preliminary design studies) for a Pluto-Kuiper Belt (PKB)
mission, intended to explore the most distant planet in the
solar system. The mission will also explore the Kuiper Belt
beyond Pluto, a source of comets and believed to be the
source of much of Earth’s water and the simple chemical
precursors of life.

The scientific value of this mission is highly dependent on a
2006 launch that achieves a flyby of Pluto well before 2020.
In order to ensure this launch date, NASA has established two
conditions that must be successfully met at the conclusion of
Phase B.

First, the mission must pass a confirmation review that will
address significant risks such as schedule and technical
milestones and regulatory approval for launch of the
mission’s nuclear power source. Second, funds must be
available. Congress provided $30 million in fiscal 2002 to
initiate PKB spacecraft and science instrument development
and launch vehicle procurement; however, no funding for
subsequent years is included in the administration’s budget
plan.

The mission, called New Horizons: Shedding Light on Frontier
Worlds, is led by Principal Investigator Dr. S. Alan Stern of
the Southwest Research Institute, Boulder, Colo. He will lead
a team including The Johns Hopkins University Applied Physics
Laboratory, Laurel, Md.; Ball Aerospace Corp., Boulder,
Colo.; Stanford University, Palo Alto, Calif.; and NASA’s
Goddard Space Flight Center, Greenbelt, Md., and Jet
Propulsion Laboratory, Pasadena, Calif.

“Both proposals were outstanding, but New Horizons
represented the best science at Pluto and the Kuiper Belt as
well as the best plan to bring the spacecraft to the launch
pad on time and within budget,” said Dr. Ed Weiler, Associate
Administrator for Space Science at NASA Headquarters,
Washington. Each team conducted a three-month concept study
including management, science content, technical aspects,
cost and schedule for a complete mission, including launch
vehicle, spacecraft and science instrument payload.

The proposal outlines how the team would undertake the major
science objectives defined in the January 2001 Announcement
of Opportunity. The spacecraft would use a remote sensing
package that includes imaging instruments and a radio science
investigation, as well as spectroscopic and other
experiments, to characterize the global geology and
morphology of Pluto and its moon Charon, map their surface
composition and characterize Pluto’s neutral atmosphere and
its escape rate.

Pluto, the smallest planet, is actually a Kuiper Belt Object,
a class of objects composed of material left over after the
formation of the other planets. Pluto has large quantities of
ices of nitrogen and simple molecules containing carbon,
hydrogen and oxygen that are the necessary precursors of
life. Given Pluto’s weak gravity, these ices would be largely
lost to space if Pluto had come close to the Sun. Instead
they remain there as a representative sample of the
primordial material that set the stage for the evolution of
the solar system as it exists today, including life.

“Visiting Pluto and other Kuiper Belt objects would be like
visiting a deep freeze containing samples of the most ancient
material in our solar system, the stuff that all the other
planets including Earth were made of,” said Dr. Colleen
Hartman, Solar System Exploration Director in NASA’s Office
of Space Science. “But the most exciting thing about going to
an unexplored planet is what we may find there that we’re not
expecting.”

NASA will work with Dr. Stern to further define the costs and
to finalize the design of the spacecraft and its
accommodation of the instrument sets. Stern, as Principal
Investigator, bringing together teams from academia, industry
and NASA centers, will lead the PKB mission. It will be
implemented following the highly successful management model
of NASA’s Discovery Program.