Mission Status Report
PASADENA, Calif. – Excellent launch precision for NASA's Mars Science
Laboratory mission has forestalled the need for an early trajectory
correction maneuver, now not required for a month or more.
That first of six planned course adjustments during the 254-day journey
from Earth to Mars had originally been scheduled for 15 days after the
mission's Nov. 26 launch on a United Launch Alliance Atlas V rocket.
Now, the correction maneuver will not be performed until later in
December or possibly January.
"This was among the most accurate interplanetary injections ever," said
Louis D'Amario of NASA's Jet Propulsion Laboratory, Pasadena, Calif. He
is the mission design and navigation manager for the Mars Science
Laboratory.
Engineers deliberately planned the spacecraft's initial trajectory to
miss Mars by about 35,000 miles (56,400 kilometers). This precaution
protects Mars from Earth's microbes, because the Centaur upper stage of
the launch vehicle, which is not thoroughly cleaned the way the
spacecraft is, leaves Earth on the same trajectory as the spacecraft.
The planned trajectory ensures that the Centaur will not hit Mars.
The launch put the spacecraft on an actual trajectory missing Mars by
about 38,000 miles (61,200 kilometers). Planned trajectory correction
maneuvers will put the spacecraft on course and on timing to land at
Mars' Gale Crater on Aug. 6, 2012, Universal Time (evening of Aug. 5,
Pacific Daylight Time).
The spacecraft experienced a computer reset on Tuesday apparently
related to star-identifying software in the attitude control system. The
reset put the spacecraft briefly into a precautionary safe mode.
Engineers restored it to normal operational status for functions other
than attitude control while planning resumption of star-guided attitude
control.
Also on Tuesday, thrusters were used as planned to slow the spacecraft's
rotation rate from 2.5 rotations per minute to 2.05 rotations per
minute. Telecommunications are active at a downlink rate of 25 kilobits
per second. Electrical output from the cruise stage solar array is 800
watts. Thrusters warmed by catalytic bed heaters were originally warmer
than expected, but use of the heaters has been reduced to keep the
thrusters at intended temperatures.
As of 9 a.m. PST (noon EST) on Friday, Dec. 2, the spacecraft will have
traveled 10.8 million miles (17.3 million kilometers) of its
352-million-mile (567-million-kilometer) flight to Mars, and will be
moving at 7,500 mph (12,000 kilometers per hour) relative to Earth and
at 73,800 mph (118,700 kilometers per hour) relative to the sun.
The Mars Science Laboratory mission will use its car-size rover,
Curiosity, to investigate whether the selected region on Mars has
offered environmental conditions favorable for supporting microbial life
and favorable for preserving clues about whether life existed.
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/ .
Saturday, December 3, 2011
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