NASA's MESSENGER Mission To Crash Into Mercury In 2 Weeks 40
astroengine writes: NASA's MESSENGER spacecraft is in the final days of an unprecedented and unexpectedly long-lived, close-up study of the innermost planet of the solar system, with a crashing finale expected in two weeks. Out of fuel, the robotic Mercury Surface, Space Environment, Geochemistry and Ranging, or MESSENGER, probe on April 30 will succumb to the gravitational pull of this strange world that has been its home since March 2011. The purpose of the mission, originally designed to last one year, is to collect detailed geochemical and other data that will help scientists piece together of how Mercury formed and evolved. "MESSENGER is going to create a new crater on Mercury sometime in the near future ... let's not be sad about that," NASA associate administrator John Grunsfeld said Thursday.
The Johns Hopkins Applied Physics Laboratory has an excellent site for looking through the pictures MESSENGER has taken and the science it's done.
how Mercury evolved? (Score:1)
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Lots of things evidently crash into it:
MESSENGER Finds Spacecraft Graveyard on Mercury [jhuapl.edu]
Backro-tastic (Score:5, Interesting)
Can we take a second and thank the person who came up with the fantastic backronym "Mercury Surface, Space Environment, Geochemistry and Ranging" for MESSENGER.
For those that don't know, Mercury was the messenger of the Gods.
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For a minute I was confused since I noticed this mentioned in an earlier article about wikipedia hoaxes but it appear that someone had just changed all the references to from Mercury to Canada https://en.wikipedia.org/w/ind... [wikipedia.org]
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They should simplify life and call it Voyager 3 or the like. That way we are not paying bureaucrats to concoct goofy acronyms that look like the Spail Chekker puked.
I realize that an aerospace contractor may have been the ones who dreamed it up, but they are still passing the cost of word-smithing on to the government indirectly because they expect to recover that salary through the income of future contacts.
Re:Backro-tastic [correction] (Score:1)
Correction: "future contracts"
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The first space probe to pass Mercury was Mariner 10 [wikipedia.org]. Mariner 11 and Mariner 12 were supposed to fly to Jupiter and Saturn, but they were renamed to Voyager 1 and Voyager 2.
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Mariners went to Mars also. Thus, "direction" doesn't appear to be the criteria. I was just using a quick and dirty example anyhow.
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Interesting.. (Score:2)
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I love reading about this stuff. Space has always been something that amazes me. It will be awesome to see what the future holds as we learn more about what is out there.
Well I can understand, Space is, after all, a huge subject.
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But like most huge subjects, nearly all of it is really, really boring and only a tiny few bits are really interesting.
And you may rest assured that those interesting bits are the ones your prof will take while his students get to waste countless hours sieving through the boring stuff. Well, if astronomy is anything like archaeology, that is.
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Well, if astronomy is anything like archaeology, that is.
The similarity ends with archaeology being poking at the shit left behind by cavemen and astronomy being poking at the shit left behind by the gods
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Its SPACE. its a HUGE subject.
I will use a bigger hammer next time.
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I got the joke. It was a lame attempt to one-up you.
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I think in this case it might well be gravity. We still haven't sufficiently solved the three body problem to the point where we can predict and hence establish stable orbits with perfection. And the sun is a mighty powerful third body where that hot marble is rolling.
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Mercury has virtually no atmosphere, even with stuff from the Sun there is no atmospheric drag on the relevant timescales. As others point out, there is a three body physics effect here, in particular, it is the Kozai effect that makes the orbit eventually intersect the surface using just gravity alone.
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Interesting. So does the Kozai effect explains why Mercury (and maybe Venus) doesn't have any moons, unlike (say) Mars, which is presumably too far away from the perturber Sun? (Or maybe Phobos and Deimos entered Martian orbit too recently for the Kozai effect to have, well, taken effect.)
Ok, reading further about the Kozai mechanism (http://www.orbitsimulator.com/gravity/articles/kozai.html), apparently it's only relevant to satellites that have (roughly) non-equatorial orbits. So I suppose if Messenger
"succumb to the gravitational pull"??? (Score:2, Insightful)
MESSENGER did NOT run out of fuel and SUCCUMB to the gravitation pull of Mercury. Mercury ran out of fuel and continued on it's gravitationally influenced trajectory which was chosen to crash it. they could have left it in an eternal orbit if they wanted too - and the journalist would probably say it "did not succumb" to gravity -
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I believe some reaction between the Sun and Mercury gradually degrades orbits of probes in the area. Being that close to the Sun makes the effect fairly large.
It may be true that if they had a bigger orbit it may have been able to stay in orbit a long time. But, scientists wanted to get closer to the planet for more detailed observations.
It's probably not a big concern anyhow because the probe would typically run out of instrument orientation fue
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In this case, the crash was not deliberate, but because the orbit is not stable due to three body effects and unevenness of Mercury's surface (it was a pretty low orbit).
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I'd qualify that and say NASA decided not to spend (precious) fuel on "parking" it in a more stable orbit. But the trade-off would be either a shorter "active" mission or observations not as close to the planet.
Obviously getting the most science from the probe trumps other issues such as museum pieces for great great great grandchildren. I'd slap them myself if they shorted current science to "save" the probe for future museums.
Note that they sometimes decide on a "controlled" crash to reduce biological c
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In this case it is gravity's fault... (Score:4, Informative)
Normally I would agree with you on how gravity gets represented and how in a lot of situations you can replace a body with the same mass black hole with no changes (although get close enough, and things do change, e.g. innermost stable orbit).
However, in this case the problem is gravity. The primary cause of orbital decay for MESSENGER is the Kozai mechanism, which is a three body interaction between the Sun, Mercury, and the probe, causing the probe's orbit to increase in eccentricity until it hits the surface. They had to keep using fuel to keep the eccentricity reasonable, especially considering it is in a pretty low orbit.
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When will people stop talking about gravity is it it is in a struggle with object X and eventually it wins. People constantly talk about "Black Holes" sucking in, "inevitable"....
MESSENGER did NOT run out of fuel and SUCCUMB to the gravitation pull of Mercury. MESSENGER [FTFY] ran out of fuel and continued on it's gravitationally influenced trajectory which was chosen to crash it. they could have left it in an eternal orbit if they wanted too - and the journalist would probably say it "did not succumb" to gravity - which is equally nonsensical. Gravity did not some get the upper hand because this spacecraft ran out of fuel. That craft will always be influenced by Mercury's gravity, no matter how many fragments it smashes into, unless a fragment gets an upwards speed of more than 4.3km/s, in which case it will ESCAPE Mercury's gravity.
FTFA:
"Following this last maneuver, we will finally declare the spacecraft out of propellant, as this maneuver will deplete nearly all of our remaining helium gas,” said Daniel O’Shaughnessy, mission systems engineer at APL. “At that point, the spacecraft will no longer be capable of fighting the downward push of the sun's gravity.”
I guess he doesn't understand gravity either -- "Downward push???"
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The pull of the Sun perturbing the orbit of something that close to Mercury causes the orbit's periapsis to lose altitute. Seems like he's correct, maybe just worded awkwardly.
+5 but unfortunately wrong (Score:3, Informative)
I can't blame people for modding the comment up, because of how much movies and some journalists get wrong with gravity. But in this case the statement came from the actual scientists and people on the project, because it is actually gravity in this case causing orbital decay. It isn't just from Mercury, but from the Sun being so near that three-body instabilities are much larger. Other comment(s) above explain in a little more detail already.
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And if I'm not friendly?