[amsat-bb] Re: Question on ANDE/RAFT/NMARS/FCAL

Joe Fitzgerald jfitzgerald at alum.wpi.edu
Sat Jul 21 18:41:26 PDT 2007

W3NJ at aol.com wrote:
>  I could 
> understand a slight difference, but it's been weeks since they re-entered. 

It's all about mass and aerodynamics (the *ballistic coefficient* is how 
engineers talk about the issue).  RAFT and NMARS were deployed together 
and were both 5 inch cubes.  NMARS deorbited earlier because it had a 
lower mass and was decelerated  by the atmosphere more quickly.  Think 
about throwing a baseball vs a whiffle ball ... if you throw both at the 
same velocity, the baseball will go much further.

FCAL and ANDE are both spheres so they slip through the atmosphere 
easier than the two cubesats.  I can't speak to their mass, perhaps Bob 
can once he returns from his trip.   My earlier analogy falls apart here 
... I have never tried to throw a baseball and a *Rubik's* *Cube together*!

-Joe KM1P

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