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Re: MIRRORS Argosy Class



At 4:42 PM 3/5/96, Brian Mansur wrote:
>Brian 4:00 PM CT 3/5/96
>
>Okay.  My first draft for the Mars Hybrid (now renamed Argosy Class) has now
>officially been hulled.  The course correction problems needed avoid the Sol
>beam during decel phase has necessitated that I go back and rework my sail
>and retro mirror design.


===========

>Okay, for decel phase, we split the Asimov's sail into two parts (or into a
>washer-like sail with a hole)  to let the maser beam fire between/through.
>
>        Beam
>     From Sol
>              !
>              !
>              !
> --------------     ---------------
>\    \                /  /
>         \           \            /         /
>                    \  \        /  /
>             A
>
>     Asimov = A
>
>     !              !
>     !              !
>     !              !
>Beams From Retro Mirror
>
>The flat horizontal  lines represent the sail and the slants are the
>connecting cables.  A cable will probably stretch between the two sails and
>is not shown for covienince.  By the way, if this ASCII art is not comming
>through, I'm genuinely sorry.  Somehow fonts seem to be different from
>person to person.

Try a non proportional font like courior.

The washer sail focusing back on a smallar drag sail is a design Forward
used in his Dragon fly series.  Assuming you intended to drop the outer
sail as a retro sail?

>Now there would still be some drag inefficiencies on any lines connecting
>the two sails and on the Asimov if we tether it between both sails but that
>might be converted to electricity for whatever uses.  To further reduce this
>drag, I thought about connecting two starship components to the sails, one
>for each sail component and tethering the two sails.  If we do this, I don't
>see how we could make a more than less structurally flimsy circular sail
>while keeping a reasonably reflective shape.
>
>Course corrections are a detail we are still working on.  I'm beginning to
>think that the tugs that I've envisioned elsewhere might be replaced by the
>ion engine of the Asimov.  It could be fired at angles although the exhaust
>would probably be into the sail.  More thought needed.

Rather than tugs, you could pull in one side of the sail to generate an off
angle thrust.  Otherwise if you tried to push with rockets the sai would
get twisted out of shape, or draged behind slightly.

Of course trying to keep the retro mirror focused, or even out of the
shadow of the ships retro mirror is probably a lost cause.

>I noticed that for this sail to work, the diameter would be greater than
>Jupiter's to let the beam through.  ARRGGHH!  On the other hand it doesn't
>have to be as precisely shaped as the retro mirror.  Still not sure how to
>correct retro-mirror's course and keep its shape.  I'm trying to figure if
>there is a way to break it down into components that will reflect at the
>slight angle needed to hit the new rig.

??????!!!!  Jupiter!

========

>I also toyed with the idea of having a one-way mirror/sail for the Asimov.
> I don't know how light we'd have o get a plastic lens for this.  Obviously
>can't use glass.  By the way.  Can we actually make a one way mirror with
>plastics?  If so, how thin?  Also, just to be clear, do microwaves bounce of
>hand mirrors better or worse than wire meshes?

One way mirrors don't really work that way.  They mainly are not very
transparent, and you make sure only the room on one side has lights on.


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Kelly Starks                       Internet: kgstar@most.fw.hac.com
Sr. Systems Engineer
Magnavox Electronic Systems Company
(Magnavox URL: http://www.fw.hac.com/external.html)

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