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International Space Station Turns Two

Posted by michael on from the space-is-wide-and-good-friends-are-too-few dept.

RedWolves2 writes "Today is ISS's second anniversary of Operations. Two years ago today NASA astronaut Bill Shepherd and Russian cosmonauts Yuri Gidzenko and Sergei Krikalev first boarded the ISS. In two years the station has grown to more then 200,000 pounds and has had 112 visitors."

13 of 233 comments (clear)

  1. and still by gspr · · Score: 4, Informative

    ...and still the people of Earth cannot tell the difference between then and than.

  2. You are all wrong! by Keebler71 · · Score: 3, Informative
    You are all wrong! Objects in orbit have both mass and weight. The term "weightless" is often misused as it only applies to the reference frame to another object in the same orbit.

    Weight (force due to gravity) = -G*M*m/(r^2)

    show me what part of that equation is zero...

    For instance, an astronaut is weightless relative to the shuttle or ISS, but still weighs 200lb or so relative to the Earth. The apparent weightless is simply due to the fact that the vehicle and the astronaut are both being accelerated toward the Earth with exactly the same magnitude, thus no RELATIVE acceleration and no perceivable weight.

    Another misconception is that object are easy to move around in "zero-g". Not so,... a large object still has the same mass as on Earth which corresponds to a lot of inertia so it is very difficult to get moving and stop again. The big difference is that there is no surface friction so once the object is moving, you don't have to apply a non-conservative force to keep it moving.

    --
    "It takes considerable knowledge just to realize the extent of your own ignorance." - Thomas Sowell
  3. Re:200,000 pounds ? by Anonymous Coward · · Score: 3, Informative

    http://faculty.millikin.edu/~jaskill.nsm.faculty.m u/slug.html

  4. Great ISS-related site by frozenray · · Score: 4, Informative


    http://heavens-above.com/ has location-based information about the flight path of the ISS, among other things. Worth a visit.

    --
    "There are already a million monkeys on a million typewriters, and Usenet is NOTHING like Shakespeare." - Blair Houghton
  5. Re:Could someone enlighten me? by Anonymous Coward · · Score: 1, Informative

    Even if something is "weightless", it still has mass. There are numerous ways to determine that... for instance, how much it accelerates for from a known amount of force. Of course, I'm sure the estimate is just based on adding up the weight on Earth of all the crap before it was sent up...

  6. You can't measure objects in space in lbs. by wackybrit · · Score: 3, Informative

    lbs (pounds) are a measure of weight. kgs are a measure of mass, although we use them as a measure of weight for convenience.

    Mass is a measurement of the amount of matter something contains, while Weight is the measurement of the pull of gravity on an object.

    Therefore, you cannot measure the weight of the ISS in pounds, since the force of gravity exerted upon it is miniscule.. so it doesn't really weigh 200,000 lbs.. it just has a mass of the kilogram equivalent of 200,000 lbs!

    The ISS would only weight 200,000 lbs if it were on Earth... but it can be 90,909 kgs in space or on Earth since kgs is a measurement of mass not weight!

    --
    mogorific carpentry experiments
    1. Re:You can't measure objects in space in lbs. by Anonymous Coward · · Score: 2, Informative

      "since the force of gravity exerted upon it is miniscule"

      Go back to physics class. Gravity still has a very profound effect on the spacestation and on the astronauts (cosmonauts) inside it. The 'weightlessness' is only because they're in perpetual free fall, not because of a lack of gravity. If the effect of gravity were miniscule, they would fly off into space, not orbit the planet.

    2. Re:You can't measure objects in space in lbs. by Dark+Marmot · · Score: 2, Informative

      In fact, lbs are units of weight but you can also
      refer to lbs mass (this from aerospace class)
      -- the more common unit of mass in the customary
      system though is the slug (32.2 lbs mass)

    3. Re:You can't measure objects in space in lbs. by Kaboom13 · · Score: 2, Informative

      This is not quite true. The Earth is pulling on the ISS just like it pulls on everything else. The pull might be slightly diminished by the distance, but not by much. The reason satelites stay in orbit (and appear weightless) is because they are moving fast enough around the earth to maintain their orbit. A basic physics book can explain it much better then I can. Slow down the ISS enough and it'll fall like a 200,000 lb brick.

  7. ISS -- first step to Mars or not? by GGardner · · Score: 4, Informative
    If we hope to ever estabilish a permanent moon base or go to Mars (or beyond) we will certainly be building upon the lessons learned in constructing the ISS (pun inteneded).

    The above is a common misconception. Richard Zubrin's Mars Direct proposal shows how to send humans to mars without the ISS. Of course, ISS keeps earthbound contractors fat, and happy.

  8. Story straight from Nasa by term0r · · Score: 3, Informative

    click here

  9. Re:200,000 pounds ? by Henry+V+.009 · · Score: 3, Informative

    Maybe you won't believe me, but will you believe an actual website claiming to be authoritive?

    LOL--It really is true. The slug is the British unit of mass--pound is the unit of force.

  10. Re:Whats it for? by C0LDFusion · · Score: 2, Informative

    6) The one place Americans have restrained themselves and not taken "unilateral action".

    I'd like to remind the poster of the above that most countries "participating" in the ISS have been defaulting on their share of it, leaving the US to pay up for a capsule that has THEIR flag on it. Then they insult us because we can't afford National Health Care.

    --
    Only in slashdot are posts of solidarity modded at -1 Redundant, while posts of antagonism are modded as -1 Flamebait.