[ExI] Recovered Dragon Capsule

[spike]

>... On Behalf Of Dan
...
>>>
>>> I wonder what the huge gash in it was caused by.
>>
>>...Apparently that's a track for the parachute lines.
>
> That's what I concluded as well.  The parachute must be inside the 
> capsule for the maximum reentry deceleration to move the CG as close 
> to the shield as possible, then the lines need to attach up top.

>...Or maybe it's a line for the float? (Would the parachute mass enough to
have much of an impact on CG, especially when the craft is carrying cargo
back?)


Regards,

Dan


_______________________________________________


Hmmm, hard to say.  I don't have access to any of the design details, but
ja, the parachutes are heavy and you want those as far forward as you can
get.  Clearly they need to go aft of the return payload, of outboard if you
get tricky with them somehow.  In this case, recall you turn the reference
system around for reentry, so the pointy end is aft.

This would be an interesting exercise.  If we have an external view of the
shield, we can estimate the center of pressure.  The shape and size of
everything aft of the shield does not matter in the CP calculation if you
are supersonic: the forces are dominated by the sonic shock waves.  From
that we can work backwards and estimate where the CG would need to go.  From
the weight of the recovery capsule, we can estimate the weight of the
parachutes.  Another approach would be to look up the weight of the recovery
chutes for Apollo.  We cannot take the weight of sky-divers chutes and scale
them: these must carry a heavy load.  

This is left for an exercise for the interested student, right now I gotta
run.

spike