[meteorite-list] MSL Completes Biggest Maneuver

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 12 Jan 2012 08:37:34 -0800 (PST)
Message-ID: <201201121637.q0CGbY3t028174_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2012-011

Spacecraft Completes Biggest Maneuver
Jet Propulsion Laboratory
January 11, 2012

PASADENA, Calif. -- NASA's Mars Science Laboratory spacecraft
successfully refined its flight path Wednesday with the biggest maneuver
planned for the mission's journey between Earth and Mars.

"We've completed a big step toward our encounter with Mars," said Brian
Portock of NASA's Jet Propulsion Laboratory, Pasadena, Calif., deputy
mission manager for the cruise phase of the mission. "The telemetry from
the spacecraft and the Doppler data show that the maneuver was completed
as planned."

The Mars Science Laboratory mission will use its car-size rover,
Curiosity, to investigate whether the selected region on Mars inside
Gale Crater has offered environmental conditions favorable for
supporting microbial life and favorable for preserving clues about
whether life existed.

Engineers had planned today's three-hour series of thruster-engine
firings to accomplish two aims: to put the spacecraft's trajectory about
25,000 miles (about 40,000 kilometers) closer to encountering Mars and
to advance the time of the encounter by about 14 hours, compared with
the trajectory following the mission's Nov. 26, 2011, launch.

"The timing of the encounter is important for arriving at Mars just when
the planet's rotation puts Gale Crater in the right place," said JPL's
Tomas Martin-Mur, chief navigator for the mission.

The mission's second trajectory correction maneuver, expected to be
about one-sixth the magnitude of this first one, is scheduled for March
26. Up to four additional opportunities for fine-tuning, as needed, are
scheduled before the arrival at Mars on Aug. 5, 2012, PDT (Aug. 6, EDT
and Universal Time).

The spacecraft's initial trajectory resulting from the launch included
an intentional offset to prevent the upper stage of the launch vehicle
from hitting Mars. That upper stage was not cleaned the way the
spacecraft itself was to protect Mars from Earth's microbes.

The Mars Science Laboratory spacecraft rotates in flight at about two
revolutions per minute. Today's maneuver included two different
components: one that changed velocity in the direction of the axis of
the spacecraft's rotation, and one that changed velocity in a direction
perpendicular to that.

The maneuver used the eight thruster engines on the cruise stage of the
spacecraft, grouped into two sets of four. It began with a thrust
lasting about 19 minutes, using just one thruster in each set and
affecting velocity along the direction of the axis of rotation. Then, to
affect velocity perpendicular to that line, each set of thrusters was
fired for 5 seconds when the rotation put that set facing the proper
direction. These 5-second bursts were repeated more than 200 times
during a period of about two hours for a total of about 40 minutes.

The maneuver was calculated to produce a net change in velocity of about
12.3 miles per hour (5.5 meters per second), combining a slight increase
in speed with a small change in direction of travel.

As of 9 a.m. PST (noon EST) on Thursday, Jan. 12, the spacecraft will
have traveled 81.2 million miles (130.6 million kilometers) of its
352-million-mile (567-million-kilometer) flight to Mars. It will be
moving at about 10,300 mph (16,600 kilometers per hour) relative to
Earth, and at about 68,700 mph (110,500 kilometers per hour) relative to
the sun.

JPL, a division of the California Institute of Technology in Pasadena,
manages the Mars Science Laboratory mission for the NASA Science Mission
Directorate, Washington.

More information about Curiosity is online at: http://www.nasa.gov/msl
and http://mars.jpl.nasa.gov/msl/ . You can follow the mission on
Facebook at: http://www.facebook.com/marscuriosity and on Twitter at:
http://www.twitter.com/marscuriosity .

Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
Guy.Webster at jpl.nasa.gov

2012-011
Received on Thu 12 Jan 2012 11:37:34 AM PST