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Messenger En Route To Mercury

Posted by timothy on from the luggage-is-going-to-phoenix dept.

Soft writes "NASA's Messenger space probe has lifted off on its second try on a Delta 2-Heavy rocket. As mentioned earlier on Slashdot, it is poised to orbit Mercury in 2011 after three flybys, as well as two flybys of Venus and one of Earth for course corrections. It will be the first probe to visit the innermost planet since Mariner 10 in 1974 and 1975. Stories on the BBC and SpaceflightNow."

5 of 120 comments (clear)

  1. I thought we knew this bit already . . . by StateOfTheUnion · · Score: 4, Interesting
    From the Spaceflight Now

    How did Mercury, believed to be 60 percent iron, end up with an oversize core, a thin shell of a crust and the highest density in the solar system? Was its crust blasted away in the distant past by a cataclysmic impact? Was it boiled away in the extreme heat of the young, nearby sun? Or were metals for some reason concentrated in the inner region of the solar nebula that coalesced to form the sun and planets?

    Perhaps my knowledge is a little dated, but I thought that the inner four planets have higher density because the sun stripped the inner solar system of light gasses like hydrogen due to the larger mass and higher gravitational field of the sun during the formation of the sun and the solar system. Outer planets are gas giants because the Sun's (or the pre-sun center of the accretion disk ) gravitational field was not strong enough to grab the light elements from the portion of the solar system that would become the gas giants (further from the center of the pre solar system accretion disk). Also, this was thought to be why Pluto is an oddball (far away from the sun, but a frozen rock of a planet) that might be an escaped moon or oort cloud refugee.

    Can anyone confirm this? Or am I citing stone age planetary science that is no longer valid?

    1. Re:I thought we knew this bit already . . . by el-spectre · · Score: 4, Interesting

      I think your science is right... what the article seems to be emphasizing is the massive iron content... Earth, whilst having an iron core, is still mostly silicon and oxygen (the mantle & crust). For some reason Mercury has more than it's fair share of iron core, compared to other inner planets. 'tis puzzling.

      --
      "Faith: Belief without evidence in what is told by one who speaks without knowledge, of things without parallel." - A.B.
  2. planet inside mercury orbit by ch-chuck · · Score: 3, Interesting

    maybe now they'll finally find Planet Vulcan

    --
    try { do() || do_not(); } catch (JediException err) { yoda(err); }
  3. 2011? How long with ion drives? by adeyadey · · Score: 4, Interesting

    I dont understand why solar-powered ion drives are not used on missions like this. Probes like the ESA SMART-1 has shown that such craft can be small & economical, and there is an abundance of solar power available for free. I understand that final orbital insertion can be a problem - could a solar ion drive deliver enough "punch", or would a supplemental booster be needed? Otherwise I understand that solar would be way more fuel/time efficient over a few years compared to carrying rocket fuel & hanging around for gravity slingshots. Am I right?

    I have even read of deep-space solar-powered mission designs that head in inside mercurys orbit, grab loads of power and then head out beyond Jupiter..

    Why arnt ion drives used more?

    --
    "You lied to me! There is a Swansea!"
  4. Mercury, messenger of the Gods? by Airw0lf · · Score: 3, Interesting

    As another poster has pointed out, officially the name is derived thus: MESSENGER stands for MErcury Surface, Space ENvironment, GEochemistry and Ranging. I was looking at this information and thought that it was a rather contrived name - kind of like the laws that the US Congress passes (PATRIOT Act, etc...) And then it occurred to me, they probably called it Messenger because in Greek mythology, Mercury was the messenger of the Gods. Or I could be completely wrong...