Hi,

Have you recently checked all the litterature speaking about the speed at
which Huygens plunged into Titan atmosphere.
Don't have you noted what I call another "mistake of style"... ?
In fact we all know that on earth the sound speed is about 331 m/s at 0°C
(or in imperial units 742 mi/h at 32F)

On Titan, mostly filled with nitrogen ( 80%) at -200°C, the sound speed is
only 174 m/s. Mach 1 is thus reached at 627.6 km/h instead of 1194 km/h like
on earth.
But it is paradoxal that all pre-flight sheets dealing with this matter
written by Cassini teams kept some kind of terrestrial value (not accurate
at all).
I can understand that it is maybe to make comparisons easier, but one more
time speaking of Mach 1.5 and saying that it is 400 m/s as I read in some
PDF is a mistake because it is only 261 m/s (and even not 400 but 497 m/s on
earth or only 257 m/s at -200°C).

To help you here is the converter :
in US/UK : http://www.cactus2000.de/uk/unit/massmac.shtml
in french : http://www.cactus2000.de/fr/unit/massmac.shtml

Thierry
http://www.astrosurf.com/lombry/titan-brumes.htm