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Re: starship-design: Re: Hull Materials

In a message dated 11/13/97 5:28:20 AM, TLG.van.der.Linden@tip.nl wrote:

>Hi Kelly,
>>>> High melting points may indeed be handy if we're going much higher than
>>>> 0.3c, then the temperatures can be similar to those of the Shuttle's
>>>> shield when entering orbit.
>>Does this mean my litium-6 sail and fuel plug will have a heating problem?
>> Cruise speed was supposed to be over .4 c.
>Yes, I think it will have a problem.
>The number (6000Watt/m^2) I mentioned assumes that all radiation is
>transferred into heat. To do that, a certain amount of stopping power is
>necessary. That is, the shield should be thick enough.
>It seems that lower energy protons will loose their energy rather fast,
>actually faster than one would realize: A 10MeV proton will come to a
>complete "standstill" after only 60 micrometers of aluminium.
>My table/formula is only valid upto 10MeV protons, so I can't be sure about
>what happens when one encounters a 80MeV proton (the energy of a proton at
>0.4c), but I assume it will not lessen the problem.

Would the microwave beam pushing the sail help clear stuff out ahead of the
ship?  Should/could we blast an area clear for the acceleration burn?