>...the decay rate of an >object in earth orbit is governed by density (mass) vs frontal area (or >average frontal area) and atmospheric density (variable). > >...This would imply >that small objects such as steel fasteners could remain in orbit >(thereby creating a hazard) long after the larger (trackable) peices >(say, from an explosion of a booster) had decayed. > >Would anyone care to comment? This argument is neglecting the peculiarities of scaling. Drag certainly is proportional to the cross sectional surface area in perpendicular plane to the velocity vector. This area is proportional to the square of the diameter of the (circular) object. The momentum of the object is what drag has to push against, and this momentum is directly proportional to mass and thus volume. Volume is proportional to the CUBE of diameter. So all things being equal and ideal, a 15cm long glove has a drag:momentum ratio of 1, then a 15 metre fabric spacecraft (i.e. a 100x GIANT glove) would have a cross section and drag 10,000 times greater, but its mass/momentum would be 1,000,000 times greater. That is, the drag relative to the momentum of the GIANT glove is only 1% of that of the regular one. To make a long story short: the glove, and anything else really small, would more quickly decay because the proportional drag versus mass is very high. This is just my two-cents, I'm no expert but I love physics. And to make this a little more on-topic: I suggest someone dig through the TLEs and plot the drag terms versus height and RCS/line zero spacecraft dimension data. -Tyler ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Wed Apr 12 2000 - 09:48:38 PDT