[meteorite-list] Deep Impact Sets Path for Asteroid Encounter in 2020

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Sun, 18 Dec 2011 18:28:45 -0800 (PST)
Message-ID: <201112190228.pBJ2SjK7003098_at_zagami.jpl.nasa.gov>

http://www.spaceflightnow.com/news/n1112/17deepimpact/

Deep Impact sets path for asteroid encounter in 2020
BY STEPHEN CLARK
SPACEFLIGHT NOW
December 17, 2011

Flying on its last bit of fuel, NASA's Deep Impact probe is carefully
reshaping its course toward a potentially hazardous near-Earth asteroid
in hopes the spacecraft can survey the body in January 2020.
 
Engineer's don't know if Deep Impact has enough fuel to reach the
asteroid, and NASA officials in Washington have not committed to funding
the extended mssion.

But that isn't stopping engineers from trying, according to Tim Larson,
Deep Impact's project manager at the Jet Propulsion Laboratory in
Pasadena, Calif.

"There is a lot of uncertainty whether we'll be able to pull this off,"
Larson said in an interview with Spaceflight Now.

Engineers estimate there are just 4.4 pounds, or 2 kilograms, of
hydrazine fuel left inside Deep Impact's propellant tank. About 190
pounds of fuel were inside Deep Impact when it blasted off in January 2005.

NASA management in Washington gave the Deep Impact team authority to
fire the spacecraft's thrusters for 140 seconds on Nov. 24, changing the
probe's velocity 19.7 mph and changings its trajectory around the sun.

The burn started aiming Deep Impact toward asteroid 2002 GT, a mystical
object that regularly crosses paths with Earth. It could be a target for
future human expeditions and it has a risk of one day colliding with Earth.

Discovered in 2002, the asteroid is nearly one-half mile wide. But
scientists do not know what it looks like or its composition.

A smaller burn by Deep Impact in October 2012 would finish targeting
asteroid 2002 GT, setting up for a high-speed flyby in January 2020,
Larson said.

"Unfortunately because of the small amount of fuel we have left, we're
pretty limited on our choices of where we can go," Larson said.

Scientists at the Jet Propulsion Laboratory identified asteroid 2002 GT
as the best opportunity to continue the Deep Impact mission, which
completed its first extended phase early this year.

"We did a search of a catalog of available bodies that could be
reachable with the fuel we have available," Larson said. "Out of that,
about a half-dozen potential bodies came up that we may be able to get
to. This is the one that seemed most feasible to get some decent
observations and science."

Deep Impact is about the size of a sport utility vehicle. It fired a
high-speed impactor into comet Tempel 1 in July 2005, blowing a hole in
the nucleus and spraying icy debris into space. The Deep Impact
mothership continued flying, and NASA offered the craft for scientists
to propose new missions.
Received on Sun 18 Dec 2011 09:28:45 PM PST