New Horizons

http://pluto.jhuapl.edu/news_center/news/20141113.php

New Horizons Set to Wake Up for Pluto Encounter
November 13, 2014

NASA's New Horizons spacecraft comes out of hibernation for the last
time on Dec. 6. Between now and then, while the Pluto-bound probe enjoys
three more weeks of electronic slumber, work on Earth is well under way
to prepare the spacecraft for a six-month encounter with the dwarf
planet that begins in January.

"New Horizons is healthy and cruising quietly through deep space-
nearly three billion miles from home - but its rest is nearly over,"
says Alice Bowman, New Horizons mission operations manager at the Johns
Hopkins University Applied Physics Laboratory (APL) in Laurel, Md. "It's
time for New Horizons to wake up, get to work, and start making history."

Since launching in January 2006, New Horizons has spent 1,873 days in
hibernation - about two-thirds of its flight time - spread over 18
separate hibernation periods from mid-2007 to late 2014 that ranged from
36 days to 202 days long.

In hibernation mode much of the spacecraft is unpowered; the onboard
flight computer monitors system health and broadcasts a weekly
beacon-status tone back to Earth. On average, operators woke New
Horizons just over twice each year to check out critical systems,
calibrate instruments, gather science data, rehearse Pluto-encounter
activities and perform course corrections when necessary.

New Horizons pioneered routine cruise-flight hibernation for NASA. Not
only has hibernation reduced wear and tear on the spacecraft's
electronics, it lowered operations costs and freed up NASA Deep Space
Network tracking and communication resources for other missions.

Ready to Go

Next month's wake-up call was preprogrammed into New Horizons' on-board
computer in August, commanding it come out of hibernation at 3 p.m. EST
on Dec. 6. About 90 minutes later New Horizons will transmit word to
Earth that it's in "active" mode; those signals, even traveling at light
speed, will need four hours and 25 minutes to reach home. Confirmation
should reach the mission operations team at APL around 9:30 p.m. EST. At
the time New Horizons will be more than 2.9 billion miles from Earth,
and just 162 million miles - less than twice the distance between Earth
and the sun - from Pluto.

After several days of collecting navigation-tracking data, downloading
and analyzing the cruise science and spacecraft housekeeping data stored
on New Horizons' digital recorders, the mission team will begin
activities that include conducting final tests on the spacecraft's
science instruments and operating systems, and building and testing the
computer-command sequences that will guide New Horizons through its
flight to and reconnaissance of the Pluto system. Tops on the mission's
science list are characterizing the global geology and topography of
Pluto and its large moon Charon, mapping their surface compositions and
temperatures, examining Pluto's atmospheric composition and structure,
studying Pluto's smaller moons and searching for new moons and rings.

New Horizons' seven-instrument science payload, developed under
direction of Southwest Research Institute, includes advanced imaging
infrared and ultraviolet spectrometers, a compact multicolor camera, a
high-resolution telescopic camera, two powerful particle spectrometers,
a space-dust detector (designed and built by students at the University
of Colorado) and two radio science experiments. The entire spacecraft,
drawing electricity from a single radioisotope thermoelectric generator,
operates on less power than a pair of 100-watt light bulbs.

Distant observations of the Pluto system begin Jan. 15 and will continue
until late July 2015; closest approach to Pluto is July 14.

"We've worked years to prepare for this moment," says Mark Holdridge,
New Horizons encounter mission manager at APL. "New Horizons might have
spent most of its cruise time across nearly three billion miles of space
sleeping, but our team has done anything but, conducting a flawless
flight past Jupiter just a year after launch, putting the spacecraft
through annual workouts, plotting out each step of the Pluto flyby and
even practicing the entire Pluto encounter on the spacecraft. We are
ready to go."

"The final hibernation wake up Dec. 6 signifies the end of an historic
cruise across the entirety of our planetary system," added New Horizons
Principal Investigator Alan Stern, of the Southwest Research Institute.
"We are almost on Pluto's doorstep!"

The Johns Hopkins Applied Physics Laboratory manages the New Horizons
mission for NASA's Science Mission Directorate. Alan Stern, of the
Southwest Research Institute (SwRI) is the principal investigator and
leads the mission; SwRI leads the science team, payload operations, and
encounter science planning. New Horizons is part of the New Frontiers
Program managed by NASA's Marshall Space Flight Center in Huntsville,
Ala. APL designed, built and operates the New Horizons spacecraft.