* Posts by Tim

2 posts • joined 28 Jul 2007

Astronauts in seven-hour ISS construction session


Re: Smiley Face

I think that you'll find that the "smiley face" is really the CSA logo. See http://www.espace.gc.ca/asc/img/includes/anim_logo.gif


Astronauts chuck fridge off space station


Atmospheric drag etc

* ISS is definitely experiencing drag due to the atmosphere. The graph at http://www.heavens-above.com/issheight.asp shows this very dramatically.

* throwing the fridge back along the ISS orbit will cause the fridge to enter an slightly eccentric orbit (the point on the ISS orbit where it was tossed will be the apogee.) With the perigee deeper into the atmosphere, it will be even more affected by drag than the ISS.

* For the record, the term pound can be either mass or weight. As Charles Manning pointed out, when "pound" is weight, the term for the mass which exterts that force under 1g is termed a "slug". However, when "pound" is used as a unit of mass, the term for the force exerted by that mass under 1g acceleration is a "poundal".

* It is possible that the internal calulations of maximum surviving chunk size were actually done in SI and converted to units that the American target audience (who have not been converted) would better understand. 39lbs is pretty close to 18Kg.

* Robin quibbled about the phrase "as large as 39lb". Apparently, Robin believes that "as large as" can only refer to linear dimensions. If you take out a "large loan" from a bank, does this mean that , when laid end-to-end, the bank notes would be rather long? Does the size of the loan decrease if one switch from $1 bills to $100 bills?

* Where'd the "31lb fridge" idea come from?? The piece of debris that was toss from the ISS was described as "1,400 lb"