Conference 7.286::space

    The Shuttle has done experiments using (for lack of a better
    description), a special seat which the astronaut straps himself
    into. The special seat is motorized to shuttle back and forth
    and somehow "measures" the astronauts weight. It's really measuring
    the astronauts mass. It apparently is used to measure any changes
    in the astronauts weight (change in mass) from day to day. The 
    last time I saw this flown on a shuttle mission was a shuttle flight
    last summer, where they had a special lab installed in the payload
    bay with a lot of human medical, & behavior experiments going on.
    I'm not sure if this helps. I'm trying to recall which shuttle
    missions were flown last summer. The STS-58 is the flight that sticks
    in my mind for one which had this experiment on board.
    
    Bob

    Hi Bob,
    
    	Where is this sort of information accessable from, thats if it is
    accessable.
      As not Knowing very much about this subject, do the experiments of
    the shuttle (STS-58) get published anywhere..?
    
    			....Alan

	I went on to the WWW and checked the spacelab status reports for the 
STS 58 mission. To paraphrase, they used a Body Mass Measuring Device, which 
serves the same purpose as a scale on earth. The chair-like device with the 
crew member strapped in, shakes slightly to measure body volume and mass in 
weightlessness. Each crew member was measured daily and the data was part of 
the metabolic experiments performed on that mission.

I'll keep looking, somewhere I suspect they have some description of the 
device and how it functions.

Susan

    In the press kit, the PI for the Body Mass Measuring Device experiment
    should be listed. One could presumably contact the PI and inquire
    about details of the experiment & results. I'm sure the PI has some
    contact with a University, and should have an Internet address.
    
    Bob

The press kit for that mission is available in the Digital Space Archive.

  http://www-space.lkg.dec.com/space-archives.html


  (postscript only for this mission)

- dave

Since weight is merely the label given to the effect caused by acceleration 
due to gravity on a mass, any other acceleration of known value can substitute.
About the most simple, but possibly hard to read, would be a spring balance
inserted in between the pivot and mass of a hand spun centrifuge. Many variants
on such a theme are possible.

		John Travell.

    
    I'd put the mass on a spring-loaded sled, release the spring and
    mesaure the linear acceleration. Acceleration can be worked backward
    from "how long did it take to get from point A to point B", which is
    a fairly simple job with the appropriate leds, sensors and timer (just
    make sure that the accelerating force is constant over the length of
    travel from point A to B). Add a calibrating feature with some known
    masses, and a damper at the other end of the sled's path, and you have
    a 0-g "scale".
    

    RE: 935.7
    I believe that's essentually how the special seat/sled that the
    Shuttle crew used to measure their mass (weight), works. 
    
    Bob

    They made a big deal out of this technique for Skylab. The
    documentaries show a couple of different versions. I imagine these have
    all been well documented.
    
    gary

    Yes, I now recall seeing the seat/sled being used in a SKYLAB
    documentary that I saw one evening around Christmas - New Years 
    on NASA Select.
    
    Bob