MESSENGER News Thread, news, updates and discussion |
MESSENGER News Thread, news, updates and discussion |
Apr 20 2005, 11:22 AM
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#101
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Member Group: Members Posts: 562 Joined: 29-March 05 Member No.: 221 |
Launched on August 3rd 2004, NASA's MESSENGER will become the first spacecraft to orbit Mercury.
News and updates are availbale via Johns Hopkins University MESSENGER website and the Kennedy Space Center's MESSENGER website. There will be an earth flyby in August followed by a couple of swings by Venus and three velocity scrubbing passages past mecury before the craft enters orbit in March 2011. April 18, 2005 status report from JHU. Extensive JHU FAQs page here. |
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Oct 23 2006, 04:04 AM
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#102
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Member Group: Members Posts: 541 Joined: 17-November 05 From: Oklahoma Member No.: 557 |
Well, the two diagrams do match up. The tick marks are a little more compressed looking in from the sun, but if you carefully trace by the intervals, you'll see in both cases that as viewed from Venus the spacecraft moves in from the sun moving westward and northward, before being flung back south. It still continues west on its departure.
It's necessary to pursue this path, flung backwards from the normal counterclockwise motion of the planets as viewed from north, in order to lose energy relative to the sun, and adjust the orbit inward toward Mercury. It is also necessary to go to high latitudes on Venus in order to adjust to the plane of Mercury's orbit. |
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Oct 23 2006, 03:04 PM
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#103
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Senior Member Group: Members Posts: 1636 Joined: 9-May 05 From: Lima, Peru Member No.: 385 |
Well, the two diagrams do match up. The tick marks are a little more compressed looking in from the sun, but if you carefully trace by the intervals, you'll see in both cases that as viewed from Venus the spacecraft moves in from the sun moving westward and northward, before being flung back south. It still continues west on its departure. It's necessary to pursue this path, flung backwards from the normal counterclockwise motion of the planets as viewed from north, in order to lose energy relative to the sun, and adjust the orbit inward toward Mercury. It is also necessary to go to high latitudes on Venus in order to adjust to the plane of Mercury's orbit. Good comments, I think a three dimensional graphic would help to view better. Also the above graphic is too small that I seems that after flyby Venus, Messenger would go away from the Venus toward Earth orbit. But, If there is a bigger (smaller scale) in a three dimensional, I would be able to see that after Venus fly-by, Messenger would go toward the South of Venus and little by little going toward on the counterclockwise. For the second fly-by in the June 6, 2007, Messenger will arrive at Venus comming from the North of Venus to South but on the opposite to Venus orbit direction? I see it is for slowing the speed as much as possible with the Venus gravitational pulling (from 13,500 km/sec at Venus 2 fly-by to 7,100 km/sec at Mercury 1 fly-by). But, when Messenger arrives at Mercury, it will be again flying the orbit around the Sun on the counterclockwise. Rodolfo |
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