[meteorite-list] At Pluto, Moons and Debris May Be Hazardous to New Horizons

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 16 Oct 2012 13:52:33 -0700 (PDT)
Message-ID: <201210162052.q9GKqXhM029165_at_zagami.jpl.nasa.gov>

http://pluto.jhuapl.edu/news_center/news/20121016.php

At Pluto, Moons and Debris May Be Hazardous to New Horizons
Spacecraft Aims to Steer Clear of "Debris Zones" During 2015 Flyby

October 16, 2012

NASA's New Horizons spacecraft is now almost seven years into its
9?-year journey across the solar system to explore Pluto and its system
of moons. Just over two years from now, in January 2015, New Horizons
will begin encounter operations, which will culminate in a close
approach to Pluto on July 14, 2015, and the first-ever exploration of a
planet in the Kuiper Belt.

As New Horizons has traveled through space, its science team has become
increasingly aware of the possibility that dangerous debris may be
orbiting in the Pluto system, putting the spacecraft and its exploration
objectives into harm's way.

"We've found more and more moons orbiting near Pluto - the count is now
up to five," says Alan Stern, principal investigator of the New Horizons
mission and an associate vice president of the Space Science and
Engineering Division at Southwest Research Institute (SwRI). "And we've
come to appreciate that those moons, as well as those not yet
discovered, act as debris generators, populating the Pluto system with
shards from collisions between those moons and small Kuiper Belt objects."

"Because our spacecraft is traveling so fast - more than 30,000 miles
per hour - a collision with a single pebble, or even a millimeter-sized
grain, could cripple or destroy New Horizons," adds New Horizons Project
Scientist Hal Weaver, of the Johns Hopkins University Applied Physics
Laboratory (APL), "so we need to steer clear of any debris zones around
Pluto."

The New Horizons team is already using every available tool - from
sophisticated computer simulations of the stability of debris orbiting
Pluto, to giant ground-based telescopes, to stellar occultation probes
of the Pluto system, to the Hubble Space Telescope - to search for
debris in orbit. At the same time, the team is plotting alternative,
more distant courses through the Pluto system that would preserve most
of the science mission but avert deadly collisions if the current flyby
plan is found to be too hazardous.

"We're worried that Pluto and its system of moons, the object of our
scientific affection, may actually be a bit of a black widow," says
Stern, who discusses this aspect of the flyby today at the annual
meeting of the American Astronomical Society's Division for Planetary
Sciences in Reno, Nevada.

"We're making plans to stay beyond her lair if we have to," adds New
Horizons Deputy Project Scientist Leslie Young, of Southwest Research
Institute. "From what we have determined, we can still accomplish our
main objectives if we have to fly a 'bail-out trajectory' to a safer
distance from Pluto. Although we'd prefer to go closer, going farther
from Pluto is certainly preferable to running through a dangerous
gauntlet of debris (and possibly rings) that may orbit close to Pluto
among its complex system of moons."

"We may not know whether to fire our engines on New Horizons and bail
out to safer distances until just 10 days before reaching Pluto, so this
may be a bit of a cliffhanger," Stern says. "Stay tuned."

New Horizons is the first mission in NASA's New Frontiers program. APL,
located in Laurel, Md., built and operates the New Horizons spacecraft
and manages the mission for NASA's Science Mission Directorate. SwRI led
the payload/instrument development and leads the New Horizons science
and mission teams from the Tombaugh Science Operations Center, located
at SwRI facilities in Boulder, Colo. For more information, go to:
http://pluto.jhuapl.edu/.


[Image]
Field of Debris? The discovery of additional small moons has raised
concerns about the possibility of rings or other debris structures in
the Pluto system that can pose hazards to New Horizons. Even a
millimeter-sized pebble's impact at New Horizons' flyby speed - about 14
kilometers per second, or more than 31,300 miles per hour - could
seriously damage the spacecraft.
Received on Tue 16 Oct 2012 04:52:33 PM PDT