From: CurtAdams@aol.com
Date: Mon Sep 09 2002 - 13:00:09 MDT
In a message dated 9/9/02 11:45:42, eugen@leitl.org writes:
>On Mon, 9 Sep 2002 CurtAdams@aol.com wrote:
>
>> You're proposing focusing a microwave beam over interstellar distances?
>> No way.
>
>It's not my proposal (duh, would I state anything so outlandish if I
>dreamed it up myself? I wouldn't dare to). I don't have the skills to
>predict properties of an optical instrument with an overall MT/s energy
>flux and an aperture lighthours to lightdays across, but whether
>phased-array or no, I consider that it is very possible to push a probe
>for the first half a year with 3 g or so (then it's pretty relativistic,
>and we can go back to carpe diem mode). Even if it takes more than 1% of
>the entire solar output.
I tried to estimate laser light for interstellar relativistic launches some
time ago and quickly came to the conclusion it doesn't work. The spread
is *way* too fast. You can get a nice boost, but nothing even vaguely
relativistic.
>Actually, you get realtime (microseconds) feedback from a self-healing
>system on the state of the damage. You can check this by testing the
>amount of bitflips in a solid-state memory in vicinity of a radiation
>source. If we want to talk vacuum-tube tech...
That tells you roughly the amount of damage. But which bonds are broken
is far more important than knowing you have 500-2000 things wrong
in a certain area. And you won't catch everything - you're going
to get lone plinks, too.
>> The high-energy secondaries are the problem in any system.
>Yes, but the regime for slow (0.1 c), fast (0.9 c) and very fast (>0.99 c)
>is different. There might be three different regimes, because ultrahard
>radiation doesn't really interact with targets.
Right. The damage will tend to be limited with increasing radiation power
as eventually much of the energy escapes without producing additional
secondaries. I don't know what the exact levels are. It would depend on
the radiation cross-section of your material, which is also hypothetical.
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