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3.5 Ton Satellite to Crash Back to Earth

Posted by chrisd on from the guess-my-pellet-gun-was-more-powerfull-than-I-thought dept.

DeadBugs writes "CNN is reporting that the NASA Extreme Ultraviolet Explorer could crash back to earth in a matter of days. It's estimated that up to 9 large pieces (4-100 lbs.) of the Satellite could survive re-entry. Unlike the Compton Gamma Ray Observatory that was guided in, this Satellite will be uncontrolled. The EUVE has only been up there since 1992.... I wonder when this sort of thing will start to be a more common event."

4 of 323 comments (clear)

  1. Incoming! by James1006 · · Score: 5, Informative

    Actually, debris entering the atmosphere (man-made and not) is a common occurrence. Happens everyday on some scale. It isn't just everyday a 3.5 ton one comes down :)

    I believe US Space Command/NASA/NORAD spends a ton of time tracking objects in close orbit, even very small ones the size of your finger.

    After all, anything going 17500 miles per hour hitting something like the space shuttle or Hubble or any other satellite (GPS, communications, spy/defense) wouldn't be pretty.

    Someone who worked for NASA at MSFC told me that they have actually had astronauts on the space shuttle change the shuttle's orbit slightly in order to avoid certain large pieces of debris.

    --

    - Nothing is true, everything is permitted
    1. Re:Incoming! by man_ls · · Score: 5, Informative

      True that. I've been inside NORAD and seen the satellite tracking facility (it's about 50 SGI Indigo and Indigo 2 workstations running a DOD-specific version of IRIX, with a second "hot backup" also used for training with identical hardware but a different room config a few floors down. (all that from only about 5 minutes in the lab...)

      It's pretty cool actually, you can open their anaylisis program and plot x; where x = the chronological number from 1 = Sputnik of the satellite launched, for a bunch of nice apogee/perigee/period/distance/elevation graphs. plot (some number I don't remember, and is probably classified anyway) plotted Mir, and the graphing was so accurate you could literally picture in your mind the space station flying around in closer and closer spirals until perigee=0 and reentry.

      But anyways-yes, they do track the stuff. And yes, they do course correct. A lot more than you might think too.

  2. info by Alien54 · · Score: 5, Informative
    EUVE Archive
    EUVE Home (UCal. Berkeley)

    Info on satellite tracking here. Track the orbit, and place bets on where it will land. (note, the farthest north is someplace in florida.)

    --
    "It is a greater offense to steal men's labor, than their clothes"
  3. Can you tell me how much it will rain tomorrow? by roystgnr · · Score: 5, Informative

    Can you tell me where a piece of paper dropped off a skyscraper will land?

    The weather in low earth orbit is just as unpredictable as the weather at the ground, and just as variable. The density of the atmosphere around satellites (and thus the drag force on them) can vary by an order of magnitude. If the satellite loses orientation (which it is essentially certain to as drag forces overcome tidal or powered stabilization) then its coefficient of drag changes as well, and unpredictably when it rotates. It may not even have just drag acting on it; even in orbit an angled surface can produce just as much lift as drag, and when the satellite hits the atmosphere its shape could produce more lift than drag.

    And of course, for every second by which the atmosphere delays reentry, the satellite has moved 5 miles in its orbit. 5 mi/s * 3600 s/hr * 9 hr gives a nice 160,000 mile strip of possible landing sites, crossing around and around the whole globe. If you'd like to gamble about the probability of something being hit by one of the chunks, though, I suggest placing your money on "no".