Ian Woollard wrote:
> Does anyone know any rules of thumb for a reentry shield? (I'm trying
> to design a reusable vehicle.)
>
> i.e. if I have a vehicle weighing X, with a cross-section of A
> reentering with a speed R then the reentry shield needs to have a mass
> of... what?
>
> The only thing I've found so far is a reference that Apollo used a
> shield mass of 15 pounds per square foot(!); but I'm unclear how to
> scale this. [presumably more area = less loading = less shield per
> square foot]
>
> Anyone have know of any documents I can check out, or know any rules of
> thumb?
It's not a matter of mass, but of the thermal capacity of your TPS.
For shuttle tile material, for example, it holds a tremendous amount
of heat with little weight so "... a shield mass of 15 lbs per square
foot ..." would clearly not apply. What you may have found is the
weight allowance for the Apollo TPS.
There are MUCH better materials today, such as the zirconium felt,
that weigh oz per square foot.
Michael
----------------------------------------------------------------------
Michael Wallis KF6SPF (408) 396-9037 [EMAIL PROTECTED]
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