NASA MESSENGER Status Report November 18, 2004

MESSENGER completed its third trajectory correction maneuver since
launch – and its last of 2004 – trimming its speed and
tweaking its course toward the Earth flyby next August.

The 48-second burst from MESSENGER’s hydrazine-fueled thrusters
reduced the spacecraft’s velocity by just over 7 miles per hour
(3.2 meters per second) relative to the Sun – easing it into a
cruising speed of about 62,030 miles (99,827 kilometers) per hour.
The maneuver started at 2:30 p.m. EST on Nov. 18; mission operators
at the Johns Hopkins University Applied Physics Laboratory in
Laurel, Maryland, began tracking it about two minutes later, when
the first signals indicating thruster activity reached the NASA Deep
Space Network tracking station near Madrid, Spain.

MESSENGER, now nearly 22.8 million miles (36.7 million kilometers)
from Earth, is in good health and operating normally. Detailed
checkouts of the science instruments and subsystems continue. The
solar-powered spacecraft continues to fly with its sunshade away
from the sun, allowing it to keep its key systems warm without using
power for heaters. Since launch last August 3, MESSENGER’s
computers have executed more than 15,000 commands from mission
control.

Visit the Mission Design section
(http://messenger.jhuapl.edu/the_mission/mission_design.html#tcm )
of the MESSENGER Web site for
graphics and more details on the latest trajectory correction
maneuver. The next "TCM" is tentatively planned for March 10, 2005.

MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and
Ranging) is a scientific investigation of the planet Mercury, and
the first NASA mission designed to orbit the planet closest to the
Sun. Dr. Sean C. Solomon, of the Carnegie Institution of Washington,
leads the mission as principal investigator. The Johns Hopkins
University Applied Physics Laboratory in Laurel, Maryland, built and
operates the MESSENGER spacecraft and manages the Discovery-class
mission for NASA.