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Farewell 2009
Farewell 2009
7 Dec 2009
(Source: Johns Hopkins Applied Physics Laboaratory)

The PI's Perspective
Farewell 2009
Alan Stern
December 2, 2009

New Horizons is now more than 1,400 days into its 9.5-year journey and
well past 15 AU (astronomical units) from the Sun. We still have about
2,050 days ahead of us before we reach the Pluto system, but on Dec. 29,
we'll reach the first of several midway milestones. As the graph below
shows, New Horizons will be closer to Pluto (the red line) than to Earth
(the blue curve). This marker puts a nice capstone on 2009, during which
we moved another 500 million kilometers closer to our favorite planet,
so far against the deep.

And on this long journey, things continue to go well. On Nov. 20 we
wrapped up 10 days of hibernation wake-up activities and put the
spacecraft back into hibernation until early January. The main goal of
the wake-up period was to repoint our communications dish antenna to
keep up with the changing position of the Earth around the Sun. (By the
way, it's this same motion that causes the blue "Earth" line in the
figure above to wiggle back and forth.)

During last month's wake-up we also downloaded several months of stored
science data from the Venetia Burney Student Dust Counter, corrected a
recently discovered bug in our fault protection system software,
completed about a dozen tracking passes to help refine our trajectory,
and uploaded instructions to run the spacecraft through early January.
All of the goals of the November wake-up were successfully completed,
and telemetry shows that New Horizons is in very good health and almost
exactly on its planned course.

Since I wrote you in early September, our ground team has been a lot
busier than our spacecraft has, since they never hibernate. In addition
to planning both the just-completed November wake-up and the upcoming
10-day January (2010) wake-up, they've also completed all but a few
final details of the nine-day, Pluto-closest-approach encounter command
load for 2015 and verified this command load on the spacecraft
simulators at the Johns Hopkins University Applied Physics Laboratory in
Laurel, Md. Our ground team has also been hard at work planning next
summer's Active Checkout (ACO), which will run from late May to early

The 2010 ACO is our fourth of the mission, so it's called ACO-4. Unlike
ACO-3, which was very light on activity (to give our ground team more
time to work on Pluto encounter planning), ACO-4 will be chockablock
with scheduled activities. Among these will be a complete spacecraft and
instrument checkout; instrument calibrations, to look for changes since
our last set of calibrations in 2008; a trajectory correction maneuver,
our first since 2007; a little cruise science focusing on the
interplanetary environment and Uranus and Neptune imaging; more
fault-protection software upgrades; some tests associated with
activities we'll be conducting at Pluto; and our first-ever full length
encounter mode test on the spacecraft.

And just in case you think the ground team still doesn't have enough to
do, they have also begun the detailed planning of the final few weeks of
our approach to Pluto that precedes the nine-day close encounter period
they've already planned out. All of this, mind you, by a team that is
about 10 times smaller than the venerable Voyager team when its Uranus
and Neptune flybys were planned in the mid- and late-1980s.

Before I close, I want to mention two other items you might find
interesting. First, on Nov. 17, a crew from the PBS television series
NOVA visited New Horizons at APL for a special, hosted by Neil deGrasse
Tyson, that is scheduled to air in early March. The episode will concern
the subject of Neil's book, "The Pluto Files." I was interviewed in our
control center and also met with Neil to discuss Pluto's planethood.
We've posted a few pictures from the shoot here:

Speaking of that always-hot topic, there's a fascinating new book out on
the same called "The Case for Pluto," written by MSNBC's science guy,
Alan Boyle. I was asked to help critique early drafts, and in my
opinion, Boyle has thought harder and more deeply about the topic than
any journalist ever has. It's a fun read too.

We're also planning our annual New Horizons science team meeting, which
occurs every January near the anniversary of our launch in 2006. Among
the topics we'll discuss in detail are plans to start searching for
Kuiper Belt Objects that we hope to fly by and reconnoiter after Pluto.
Those searches will begin next summer and continue through 2011 and
2012. Hopefully, they'll net us four to 10 potential targets.

That's my update for now. Thanks for following our journey to a new
frontier. I'll be back in January, after the next time we wake up our
spacecraft. In the meantime, keep on exploring, just as we do!

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Last Updated: 11 May 2011