MESSENGER Lines Up for Venus Flyby

http://messenger.jhuapl.edu/news_roo..._02_22_06.html

Status Report: MESSENGER Lines Up for Venus Flyby
February 22, 2006

MESSENGER trajectory correction maneuver 10 (TCM 10) lasted just over
two minutes and adjusted its velocity by about 1.4 meters per second
(4.6 feet per second). The short-duration maneuver placed the
spacecraft
on track for its next major mission event: the first Venus flyby on
October 24, 2006.

Having completed six successful small TCMs that utilized all 17 of the
spacecraft's thrusters, this latest maneuver was the first to rely on
the four B-side thrusters. During this maneuver, the thrusters on the
opposite side of the spacecraft reduced a build-up of angular momentum
due to an unseen force that causes the spacecraft to rotate if left
uncorrected. (This maneuver was only the seventh actual TCM for
MESSENGER; the spacecraft's trajectory was so close to optimal after
TCM
3 and TCM 6 that planned TCMs 4, 7 and 8 weren't necessary.)

Today's maneuver started at 11 a.m. EST; mission controllers at The
Johns Hopkins University Applied Physics Laboratory (APL) in Laurel,
Maryland, verified the start of the maneuver within 11 minutes and 48
seconds, when the first signals indicating spacecraft thruster activity
reached NASA's Deep Space Network tracking station outside Goldstone,
California.

At the start of the maneuver, the spacecraft was 132 million miles (212
million kilometers) from Earth and 83 million miles (133 million
kilometers) from the Sun, speeding around the Sun at 68,163 miles
(109,698 kilometers) per hour.

For graphics of MESSENGER's orientation during the maneuver, visit the
"Trajectory Correction Maneuvers" section of
http://messenger.jhuapl.edu/the_miss...on_design.html.

Earth Flyby Image Gallery Now Online

MESSENGER's Mercury Dual Imaging System (MDIS) acquired spectacular
images during the Earth flyby in August 2005, including a "film" of our
home planet as it receded in the distance. Now, you can browse through
the best of the MDIS flyby frames on the MESSENGER Web site! Visit the
MDIS Earth Flyby gallery at
http://cps.earth.northwestern.edu/MESSENGER_20050802/.

------------------------------------------------------------------------

MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and
Ranging) is a NASA-sponsored scientific investigation of the planet
Mercury, and the first space mission designed to orbit the planet
closest to the Sun. The MESSENGER spacecraft launched on Aug. 3, 2004,
and after flybys of Earth, Venus and Mercury will start a yearlong
study
of its target planet in March 2011. Dr. Sean C. Solomon, of the
Carnegie
Institution of Washington, leads the mission as principal investigator.

The Johns Hopkins University Applied Physics Laboratory built and
operates the MESSENGER spacecraft and manages the Discovery-class
mission
for NASA.