http://messenger.jhuapl.edu/news_roo..._07_21_05.html

Status Report: MESSENGER Lines Up for Earth Swingby
July 21, 2005

MESSENGER's fifth trajectory correction maneuver lasted just 23 seconds
and adjusted its velocity by less than half-a-foot per second. But the
fleeting July 21 maneuver went a long way in keeping MESSENGER on track
for the upcoming gravity-assist flyby of Earth.

Carried out by two small thrusters that poke through MESSENGER's
sunshade, the maneuver pinpointed the craft for a closest approach of
1,458 miles (2,347 kilometers) over central Asia at 3:13 p.m. EDT on
Aug. 2. Mission design team members say that directing MESSENGER along
just the right path above Earth will mean smaller course-correction
maneuvers on the way to the 2006 gravity-assist flyby at Venus -
ultimately saving fuel for later in the mission.

Today's maneuver started at 2 p.m. EDT; mission controllers at The
Johns
Hopkins University Applied Physics Laboratory (APL) in Laurel,
Maryland,
verified the start of the maneuver within 14 seconds, when the first
signals indicating spacecraft thruster activity reached NASA's Deep
Space Network tracking station outside Madrid, Spain. The spacecraft
was
2.6 million miles (4.3 million kilometers) from Earth at the time,
speeding around the Sun at 66,738 miles (107,404 kilometers) per hour.

The Earth flyby sends the spacecraft toward Venus; the first of two
Venus flybys is planned for October 2006.

Click here to see graphics of MESSENGER's configuration during the
maneuver
http://messenger.jhuapl.edu/the_mission/mission_design.html#tcm