Automated Transfer Vehicles

I'm really not getting' it. If you heat your crucible with a mirror located
to the North of the crucible, and your venturi/nozzle opening from the
crucible is aimed to the South, your result is thrust to the north, AND it
seems to me that any obscuring deposits would be leaving the neighborhood of
the crucible AND mirror very quickly and in the opposite direction from the
mirror. How then does it impair the mirror?

From: Al Globus
Sent: Wednesday, March 09, 2011 12:31 AM
To: spacesettlers@yahoogroups.com
Subject: Re: [spacesettlers] Automated Transfer Vehicles

On Mar 7, 2011, at 5:47 AM, Combs, Mike wrote:

> One criticism I've heard of using mirrors for vaporization
> propulsion (I think this was in regard to moving asteroids) is that
> it's hard to keep the vaporizing material from coating the mirror,
> steadily reducing its effectiveness.
>
You have to have some way to clean the mirror. I once did some
analysis of this for asteroid return. Unfortunately, I don't seem to
have saved it. If memory serves, you have to clean the closest-to-the-
asteroid optical element on a time scale of hours. The calculation
involves the velocity and mass of the material you must eject, the
potion of the 3D angle the optical element occupies, and the depth of
material deposited before the mirror degrades substantially.

However, given the state of my memory I wouldn't put too much stock in
the number.

>
> Regards,
>
> Mike Combs
>
> From: spacesettlers@yahoogroups.com [mailto:spacesettlers@yahoogroups.com
> ] On Behalf Of Victor Smith
> Sent: Saturday, March 05, 2011 4:25 PM
> To: spacesettlers@yahoogroups.com
> Subject: Re: [spacesettlers] Automated Transfer Vehicles
>
> Mike, this is just a thought, and I may be way out of line with
> reality, but what if we used a big mirror and focused it as a solar
> cooker onto the trash, turning it molten, and then use it for
> propulsion, either using little molten pieces or actual plasma if it
> got hot enough? We'd probably need to construct some kind of
> container that wouldn't melt, but it seems doable. I;'m not a
> scientist, though, so I could easily be mistaken...
>

NASA's first theme for lunar exploration is: "Human Civilization --
Extend human presence to the Moon to enable eventual settlement."

Al Globus
alglobus.net

The views expressed in this email are only my opinions and are not the
position of any organization I'm familiar with.