Rabu, 16 Maret 2011

NASA Chat: MESSENGER Prepares to Orbit Mercury

After more than a dozen laps through the inner solar system, NASA's MESSENGER spacecraft will move into orbit around Mercury on Mar. 17, 2011. The durable spacecraft -- carrying seven science instruments and fortified against the blistering environs near the sun -- will be the first to orbit the innermost planet.

On Wednesday, Mar. 16, from 10-11 a.m. EDT, chat experts Jimmy Lee, NASA MESSENGER mission manager, and Mike Galuska, chief engineer of the Discovery, New Frontiers and Lunar Quest Program Office at NASA's Marshall Space Flight Center in Huntsville, Ala., will answer your questions about MESSENGER'S orbital insertion.

Joining the chat is easy. Simply visit this page on Wednesday, Mar. 16. The chat window will open at the bottom of this page, and you can log in a few minutes before the chat begins at 10:00 a.m. EDT. See you in chat!


On Mar. 17 at 8:45 p.m. EDT, MESSENGER -- having pointed its largest thruster very close to the direction of travel -- will fire that thruster for nearly 14 minutes, with other thrusters firing for an additional minute, slowing the spacecraft by 862 meters per second (1,929 mph) and consuming 31 percent of the propellant that the spacecraft carried at launch. Less than 9.5 percent of the usable propellant at the start of the mission will remain after completing the orbit insertion maneuver, but the spacecraft will still have plenty of propellant for future orbit correction maneuvers.

The orbit insertion will place the spacecraft into a 12 hour orbit about Mercury with a 200 kilometer (124 mile) minimum altitude. At the time of orbit insertion, MESSENGER will be 46.14 million kilometers (28.67 million miles) from the sun and 155.06 million kilometers (96.35 million miles) from Earth.

MESSENGER has been on a six year mission to become the first spacecraft to orbit Mercury. The spacecraft followed a path through the inner solar system, including one flyby of Earth, two flybys of Venus, and three flybys of Mercury. This impressive journey is returning the first new spacecraft data from Mercury since the Mariner 10 mission over 30 years ago. 

Sumber :http://www.seopledge.com/restoring-online-reputation/