Slashdot Mirror

← Back to Stories (view on slashdot.org)

Columbia's Final Minutes in Detail

Posted by michael on from the riding-the-rocket dept.

grub writes "This article on Newsday has an excerpt from 'Comm Check... The Final Flight of Shuttle Columbia,' by Michael Cabbage and William Harwood describing the last minutes of Columbia's final flight in detail."

5 of 494 comments (clear)

  1. Hot Gas != Plasma by RobertB-DC · · Score: 5, Informative
    From the article: ...and that a plume of super-heated plasma entering through that breach had destroyed the wing and triggered the destruction of the orbiter.

    While original reports used the term "plasma", there's a good explanation at space.com's Columbia FAQ that explains that the hot gas that entered the shuttle's wing was *not* "plasma", as defined by science:
    PLASMA: What is it?

    [IMPORTANT NOTE: Officials now say that the hot gas that surrounded Columbia and appeared to breach the craft had probably not yet reached the plasma state.]

    Plasma is sometimes called a fourth state of matter (in addition to solid, liquid, gas). It's created when gas is superheated and electrons are stripped out, leaving electrically charged particles.
    Not to be a science nazi, but there's an important distinction between sci-fi-sounding "plasma" and the mundane -- but still deadly -- "very hot gas".
    --
    Stressed? Me? Of course not. Stress is what a rubber band feels before it breaks, silly.
  2. Re:May their souls rest in peace. by sahonen · · Score: 5, Informative

    There's a memorial at Cape Canaveral with the names of ALL of the people who have died in our pursuit of outer space.

    --
    Make me a friend and I'll mod you up
  3. Atlantic Monthly by Sean80 · · Score: 5, Informative

    Above and beyond this article, if you can get your hands on the article on the Colombia tragedy which was published in Atlantic Monthly, do it. As always for Atlantic Monthly, easily the most intelligent commentary I've seen about the event, and a couple of closing sentences that will stay with me forever.

    1. Re:Atlantic Monthly by jhsiao · · Score: 5, Informative

      The Atlantic Monthly article was in the November 2003 issue. It's available online here.

  4. Definition of plasma... by Dr.+Zowie · · Score: 5, Informative
    A gas doesn't have to be fully ionized to be plasma. The transition comes gradually as more and more of the gas is ionized. The crucial parameter is the ratio of the average spacing of the molecules, and something called the "Debye radius", that measures the distance over which charge neutrality holds (that is to say, plasmas are charge-neutral mixes of positively and negatively charged particles; so if you add, say, some extra positive charges to a small region you will attract a cloud of negative charges to cancel it out. The Debye radius tells you the size of the cloud).

    To be a plasma, the gas should have many free electrons (or ions) in each Debye length. There could be many more neutrals, just along for the ride, in the same space.

    Most molecular gases become more or less fully ionized at around 10,000 degrees Kelvin (give or take a factor of four or so, depending on composition) since that's the temperature at which the collision energy becomes significant compared to valence electron binding energies, so most collisions can make new ions. So anything hotter than that is definitely plasma.

    But even a fraction of a percent ionization is often enough to give you the nice bulk behavior of a plasma, because the ionized particles do their thing and drag along the neutral ones by collision. Depending on the density, it's probably reasonable to call the 8,000F (3800K) gases "plasma".