A short maneuver today kept MESSENGER on track for its Aug. 2 flyby of Earth – the major gravity assist that starts the next leg of the spacecraft's journey toward Mercury.
Mission controllers at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., verified the start of the maneuver within 48 seconds, when the first signals indicating spacecraft thruster activity reached NASA's Deep Space Network tracking station outside Madrid, Spain. The maneuver, which started at 10:30 a.m. Eastern Daylight Time and lasted just over 174 seconds, slowed the spacecraft by about 2.5 miles per hour (1.1 meters per second). At the time MESSENGER was about 8.9 million miles (14.3 million kilometers) from Earth, moving around the Sun at nearly 69,200 miles (110,720 kilometers) per hour.
[Click here to see graphics of MESSENGER's configuration during the maneuver]
Today's was the fourth trajectory correction maneuver since MESSENGER launched last Aug. 3. Early post-maneuver analysis shows that MESSENGER is on track for a closest approach some 1,458 miles (2,347 kilometers) over Mongolia in central Asia on August 2 – though the team has two opportunities in late July to carry out another small course correction if necessary.
The Earth flyby sends the spacecraft toward Venus; the first of two Venus flybys is planned for October 2006.
Animation Premieres on the Web: Wonder what MESSENGER will "see" as it flies past Earth, or as it zips past Venus and Mercury later in its historic flight? Check out the latest summer blockbusters on the MESSENGER Web site's animation page (http://messenger.jhuapl.edu/the_mission/movies.html). The QuickTime movie files show views from MESSENGER, or from above Earth, Venus and Mercury as the spacecraft flies by and, eventually, settles into orbit around the innermost planet in 2011.
Scholarship Winners: Congratulations to the winners in the second annual MESSENGER scholarship competition! Anna Rothenbaum of Oak Park, Ill., topped the group with a $1,250 scholarship. Kyle Wilkins of Durham, N.C., earned a $750 award, followed by Daniel Asselin of West Springfield, Mass., who won $250.
The MESSENGER scholarship program was created to expand interest in the MESSENGER mission and to support continuing education. College-bound high school seniors are eligible; winners are selected based on grade-point-average and a short essay on what we'll learn from the first mission to orbit Mercury. Watch the MESSENGER Web site for details on the 2006 competition later this year.