From: ssi!lfa@uunet.UU.NET ("Louis F. Adornato")
Subject: Re: Drop nuc waste into sun
X-Added: Forwarded by Space Digest
Organization: [via International Space University]
Original-Sender: isu@VACATION.VENARI.CS.CMU.EDU
Distribution: sci
Date: Fri, 9 Oct 1992 14:40:18 GMT


Nick Haines writes:
>
> In the same way that the sun's gravity pulls the Earth towards the
> sun? Wrongo. Whatever we launch from Earth starts off in solar orbit
> (because the Earth is in solar orbit), and has to dump all of its
> orbital velocity (i.e. 30 km/sec) in order to fall into the sun. This
> is much more expensive than launching to solar escape velocity and
> leaving the solar system. Do the sums.
>

1 - The initial change in orbital veliocity (wrt the sun) only needs to be
    large enough to drop apahelion to the orbit of Venus (about .5 au,
    if I recall correctly).  From there a gravity assist maneuver can
    be used to provide the remaining delta-v.

2 - A solar escape traj. would accomplish the same mission objective; get
    the waste out of the biosphere for good.  I wouldn't want to put any
    Voyager type plaques on it, though; you don't want the Galactic EPA
    to be able to trace the source.  The point is, if it takes less delta-v
    to go to escape, then that's a Good Thing.

3 - I have the luxury of speaking from near total ignorance on this (i.e,
    more knowledgeable than >99% of Americans (and <7% of Japanese), but
    not really qualified to talk about it on the net), but I read once
    that the _really_ hot part of spent fuel (the major source of high
    level waste) can be extracted chemically.  Further, the portion of
    the nasties is pretty low; the entire world supply of spent fuel
    could be reduced to a mass that could be lifted in one or two
    shuttle missions, even after adding buffers to keep it from going
    critical and glassifying the whole mess.  I also heard rumors about
    15 years ago that someone at Alfred U. (known in some circles as
    Corning's independent research arm) got a grant to work on the
    glassification process.  Could someone more qualified please comment?

4 - I don't think leaving waste at L5 (or a heliocentric with perihelion
    <1AU) is a good idea.  You never know if technology will someday
    enable crazies to recover something left in a parking orbit (and
    they wouldn't have to make a bomb out of it - a small amount of
    this in a water table or reservior would be a _lot_ more
    destructive).  It's conceivable that future generations might have
    an urgent need for it, but I'd suspect that if they no longer had
    the capability to mine and manufacture new fuel, they won't have
    the capability to recover used fuel from orbit and reprocess it.
    Someday our descendents _might_ build a spacefaring civilization,
    and it _might_ find having fissionables available in orbit useful,
    but there will _certainly_ still be nut cases among them who might 
    find the same fissionables useful for completely different reasons.

    As for crash landing it on the Moon, I personally dislike the idea
    of poisoning something before we've had a chance to explore it; it
    seems pretty short sighted to make a portion of the Moon even more
    hazardous than it already is, before we know if it can be better
    exploited in some other way.  Wouldn't it be a kick in the butt if
    the spot we chose for a Lunar waste repository turned out to be
    TMA-1's home address?

Lou Adornato                 |    "Sure, the cow may have jumped over the
Supercomputer Systems, Inc   |      moon, but she burned up on reentry"
Eau Claire, WI               | The secretary (and the rest of the company)
uunet!ssi!lfa or lfa@ssi.com | have disavowed any knowledge of my actions.