To Pluto and Beyond : The New Horizons Mission
Hal Weaver
New Horizons, which initiates the NASA New Frontier
program of mid-sized missions, will provide the first scientific
reconnaissance of the Pluto-Charon system and is scheduled for launch
in January 2006. An encounter with Jupiter at a flyby distance of
2-45 AU about 13 months after launch provides a gravity boost
for the spacecraft's journey to Pluto and an opportunity for both Pluto
encounter practice and cruise science. New Horizons carries a
sophisticated suite of instruments to perform ultraviolet and infrared
spectroscopy, panchromatic and color optical imaging, and charged
particle and dust measurements, all within a spacecraft having a total
mass of ~465 kg and total power output of ~190 W at the time
of Pluto encounter in July 2015. The primary scientific objectives of
New Horizons are to characterize the global geology and
morphology of Pluto and Charon, map the surface composition of Pluto
and Charon, and characterize the neutral atmosphere and its escape
rate, but many other important scientific objectives will be addressed
as well. New Horizons has the capability to image Pluto with a
resolution exceeding that provided by the Hubble Space Telescope
for at least 90 days prior to closest approach at a distance of
0,000 km from the surface, at which time a resolution of
00 m will be achieved for selected regions near the terminator.
After encounter, the spacecraft will pass through the shadows of both
Pluto and Charon, which enables radio and ultraviolet occultation
measurements of their atmospheres. In an extended mission phase, the
spacecraft will be re-targeted to encounter one or more Kuiper belt
objects (KBOs), roughly 3 years after the Pluto encounter. The
scientific objectives for the KBO encounters are similar to those for
the Pluto encounter, except that no detectable atmosphere is expected
at those large heliocentric distances (~42 AU).