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NASA Plans Probe to the Sun

Posted by CmdrTaco on from the hope-they-bring-suntan-lotion dept.

FudRucker writes "For more than 400 years, astronomers have studied the sun from afar. Now NASA has decided to go there. 'We are going to visit a living, breathing star for the first time,' says program scientist Lika Guhathakurta of NASA Headquarters. 'This is an unexplored region of the solar system and the possibilities for discovery are off the charts.'"

7 of 352 comments (clear)

  1. Re:Okay? by Eudial · · Score: 5, Informative

    And how exactly do you plan to do that? Do we have any material that won't melt under the intense heat? It isn't that hot. The surface is merely 5800 K. We achieve and contain that sort of temperature on a regular basis here on earth.

    The problem isn't to contain such a temperature, but to do it in a way that is compatible with space travel (i.e. not involving heavy and brittle insulation.)
    --
    GAAH! MY PRINTER IS ON FIRE!!! PUT IT OUT! PUT IT OUT!
  2. Re:Okay? by Zymergy · · Score: 5, Informative

    No. Not Really.
    And certainly not at the temperature of the Sun's corona (which probes will most likely have to travel through to get to the inner 'cooler' layers..)
    This is where we need 'shielding' technology similar to Star Trek, or to jump physical dimensions directly into the desired location with technology similar to Event Horizon, etc..

    "The coolest layer of the Sun is a temperature minimum region about 500 km above the photosphere, with a temperature of about 4,000 K." ... "Above the temperature minimum layer is a thin layer about 2,000 km thick, dominated by a spectrum of emission and absorption lines. It is called the chromosphere..." ... "Above the chromosphere is a transition region in which the temperature rises rapidly from around 100,000 K to coronal temperatures closer to one million K." http://en.wikipedia.org/wiki/Sun

    "The chemical element with the highest melting point is tungsten, at 3695 K (3422 C, 6192 F) making it excellent for use as filaments in light bulbs. The often-cited carbon does not melt at ambient pressure but sublimates at about 4000 K; a liquid phase only exists above pressures of 10 MPa and estimated 4300-4700 K. Tantalum hafnium carbide (Ta4HfC5) is a refractory compound with a very high melting point of 4488 K (4215 C, 7619 F)" http://en.wikipedia.org/wiki/Melting_point
    Even diamonds are not tough enough... Above 1700 C (1973 K / 3583 F) diamonds are converted into graphite.

  3. Re:Okay? by e2d2 · · Score: 4, Informative

    Yes the surface is only around 5800K, hot enough to melt any known material. But the corona surrounding the surface is over 10^6K. I'm curious how they intend to handle such intense energy. Not just heat energy, but insane amounts of radiation across the spectrum. This will be quite interesting from an engineering standpoint.

  4. Re:Okay? by Timothy+Brownawell · · Score: 5, Informative

    Since the corona isn't dense enough for the heat to be a problem, all they have to worry about is the radiation. Since that's all coming from the same direction, they can just hide behind something (the thing labeled "thermal shield" in the picture).

  5. Re:Okay? by ahecht · · Score: 5, Informative

    But they're not entering the corona. From TFA:

    At closest approach, Solar Probe+ will be 7 million km or 9 solar radii from the sun. There, the spacecraft's carbon-composite heat shield must withstand temperatures greater than 1400o C and survive blasts of radiation at levels not experienced by any previous spacecraft.
    I'm not saying 1400 degrees isn't hot, but it's not unmanagable.
  6. Re:Bad project name by flosofl · · Score: 4, Informative

    Of course, originally, Icarus was the name of a certain Greek god...
    No, Icarus was not a god. He was the son of Daedalus. Daedalus was an artificer (engineer) who designed the maze in which the Minotaur was imprisoned. Basically a prisoner of the king of Minos, he fashioned two sets of wooden frames to which he attached feathers with beeswax for himself and his son to escape. Daedalus escaped, but despite multiple warnings, Icarus flew too close to Apollo's chariot (the sun), melted the wax and plunged to his death.
    --
    "This calls for a very special blend of psychology and extreme violence" - Vyvyan "The Young Ones"
  7. Re:That doesn't really answer the question by Timothy+Brownawell · · Score: 4, Informative

    The mission is 7 years long. In that time, wouldn't the heat shield reach thermal equilibrium, and become extremely hot itself, if not melt? Sure. At a distance of 9 solar radii (closest approach, per article) the sun covers (area of circle) / (surface of sphere 9x as big) = 1/(4*9^2) of the sky. For radiative equilibrium, the relative temperature will be the fourth root of that, or about .236 of the temperature of the sun (6000 C). That comes to 1416 C, which is remarkably close to the 1400 C the article says the heat shield will have to withstand.