[meteorite-list] NASA's New Horizons Spacecraft Stays the Course to Pluto

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 1 Jul 2015 17:50:38 -0700 (PDT)
Message-ID: <201507020050.t620oc6a017691_at_zagami.jpl.nasa.gov>

July 01, 2015

RELEASE 15-143

NASA's New Horizons Spacecraft Stays the Course to Pluto

NASA's New Horizons spacecraft is getting a final "all clear" as it
speeds closer to its historic July 14 flyby of Pluto and the dwarf planet's
five moons.

After seven weeks of detailed searches for dust clouds, rings, and other
potential hazards, the New Horizons team has decided the spacecraft will
remain on its original path through the Pluto system instead of making a late
course correction to detour around any hazards. Because New Horizons is
traveling at 30,800 mph (49,600 kph), a particle as small as a grain of rice
could be lethal.

"We're breathing a collective sigh of relief knowing that the way appears
to be clear," said Jim Green, director of planetary science at NASA. "The
science payoff will be richer as we gather data from the optimal flight path,
as opposed to having to conduct observations from one of the back-up
trajectories."

Mission scientists have been using the spacecraft's most powerful
telescopic camera, the Long Range Reconnaissance Imager (LORRI), to look for
potential hazards, such as small moons, rings, or dust, since mid-May. The
decision on whether to keep the spacecraft on its original course or adopt a
Safe Haven by Other Trajectory, or "SHBOT" path, had to be made this week
since the last opportunity to maneuver New Horizons onto an alternate
trajectory is July 4.

"Not finding new moons or rings present is a bit of a scientific surprise
to most of us," said principal investigator Alan Stern of the Southwest
Research Institute (SwRI) in Boulder, Colorado. "But as a result, no engine
burn is needed to steer clear of potential hazards. We presented these data
to NASA for review and received approval to proceed on course and plan. We
are 'go' for the best of our planned Pluto encounter trajectories."

New Horizons formed a hazard analysis team in 2011, after the discovery of
Pluto's fourth moon, Kerberos, raised concerns the cratering of these moons
by small debris from the outer area of the solar system known as the Kuiper
Belt, could spread additional hazardous debris into New Horizons' path.
Mission engineers re-tested spare spacecraft blanketing and parts back on
Earth to determine how well they would stand up to particle impacts, and
scientists modeled the likely formation and locations of rings and debris in
the Pluto system. By the time New Horizons' cameras were close enough to
Pluto to start the search last month, the team had already estimated the
chances of a catastrophic incident at far less than one percent.

The images used in the latest searches that cleared the mission to stay on
its current course were taken June 22, 23 and 26. Pluto and all five of its
known moons are visible in the images, but scientists saw no rings, new
moons, or hazards of any kind. The hazards team determined that satellites as
faint as about 15 times dimmer than Pluto's faintest known moon, Styx,
would have been seen if they existed beyond the orbit of Pluto's largest
and closest moon, Charon.

If any rings do exist, the hazard team determined they must be extremely
faint, reflecting less than one 5-millionth of the incoming sunlight.

"The suspense - at least most of it - is behind us," says John
Spencer, of SwRI, who leads the New Horizons hazard analysis team. "As a
scientist I'm a bit disappointed that we didn't spot additional moons to
study, but as a New Horizons team member I am much more relieved that we
didn't find something that could harm the spacecraft. New Horizons already
has six amazing objects to analyze in this incredible system."

The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland,
designed, built, and operates the New Horizons spacecraft, and manages the
mission for NASA's Science Mission Directorate. The Southwest Research
Institute, based in San Antonio, 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,
Alabama.


For more information on the New Horizons mission, including fact sheets,
schedules, video and images, visit:


*http://www.nasa.gov/newhorizons*


or


*http://solarsystem.nasa.gov/planets/plutotoolkit.cfm*


Follow the New Horizons mission on Twitter [1] and use the hashtag
#PlutoFlyby to join the conversation. Live updates will be available on the
mission Facebook page [2].


-end-
Received on Wed 01 Jul 2015 08:50:38 PM PDT