For guns, see:
Robock, Alan, Allison B. Marquardt, Ben Kravitz, and Georgiy Stenchikov,
2009: The benefits, risks, and costs of stratospheric geoengineering.
/Geophys. Res. Lett./, *36*, L19703, doi:10.1029/2009GL039209.
http://climate.envsci.rutgers.edu/pdf/2009GL039209.pdf
For bubbles, see:
Robock, Alan, 2011: Bubble, bubble, toil and trouble. An editorial
comment. /Climatic Change/, doi:10.1007/s10584-010-0017-1.
http://climate.envsci.rutgers.edu/pdf/Bubble.pdf
Alan
Alan Robock, Professor II (Distinguished Professor)
Editor, Reviews of Geophysics
Director, Meteorology Undergraduate Program
Associate Director, Center for Environmental Prediction
Department of Environmental Sciences Phone: +1-732-932-9800 x6222
Rutgers University Fax: +1-732-932-8644
14 College Farm Road E-mail: [email protected]
New Brunswick, NJ 08901-8551 USA http://envsci.rutgers.edu/~robock
On 4/4/2011 8:50 PM, [email protected] wrote:
Andrew etal
1. I once looked at an all-electromagnetic (linear motor) launch
approach that might be a low cost alternative for what you want to
do. Should be a lot of literature on it.
2. Changing subject, I don't believe this list has had mention of
an alternative (bubbles - entirely ground-based) albedo-modifying
approach.. Hopefully others can point out serious risks, if applied
soon to the Arctic, which application isn't specifically in the
following Seitz draft article:
http://dash.harvard.edu/bitstream/handle/1/4737323/Seitz_BrightWater.pdf?sequence=1
Ron
----- Original Message -----
From: "Andrew Lockley" <[email protected]>
To: "geoengineering" <[email protected]>
Sent: Monday, April 4, 2011 5:43:40 PM
Subject: [geo] Another look at gunnery?
Hi
I've been going over some reports and notes recently, notably the
Aurora report
http://people.ucalgary.ca/~keith/Misc/AuroraGeoReport.pdf
<http://people.ucalgary.ca/%7Ekeith/Misc/AuroraGeoReport.pdf>
The report makes it pretty clear that they've not done a huge amount
to expand on gunnery as a tool. Specifically, the report states that:
" In the 80-100 kft range, the relative simplicity of
the gun system begins to look attractive despite the high recuring
cost of shells, if the payload fraction can be increased"
Back to basics here. Gunnery was developed by the military. Navies
need portable guns that aren't fired often - the exact opposite design
criteria that geoengineers need. Sailors therefore have short thick
barrels with massive overpressures, and robust shells to withstand the
high g forces a short barrel requires.. This is absolutely nothing
like what we need for geoengineering.
We need long guns that work at low overpressure. Low overpressure
means a lightweight shell casing, a less tight barrel seal leading to
lower friction and hence lower wear and thus lower costs.
I think we need to look at completely different gunnery technologies,
as well as just looking at gun redesign. My favorite is the ram
launcher. This works with a loose (sub calibre) shell as it doesn't
rely on barrel friction, so there's not the wear and cooling problem
you get with a gun. It doesn't require expensive propellants, as you
can run it on a cheap fuel/air mix. The acceleration is continuous,
not declining like with a gun - so it's much gentler. In fact,
accelerations as low as 600g with a 1.2km barrel are possible - and
that still gives you 8kms/s launch speed - well over what's needed for
accessing the stratosphere. That's 1/10th the acceleration in a
conventional gun (although you do need to initiate the projectile with
a primary launcher - a ram accelerator can't self start).
In case people need a reminder, the ram projectile works by firing a
loose-fitting projectile which relies on aerodynamic effects to
ingnite fuel behind it by compression ignition, like a ramjet. It
travels through the propellant, rather than being pushed in front of it.
As a result of the loose fit and low launch stresses, the shells are
likely to be very much thinner, cheaper and less well-engineered than
conventional shells, and it may even be possible to make the shells
reusable or at least recyclable.
What do other people think of this?
For more info on the technology, check the following links:
http://www.tbfg.org/papers/Ram%20Accelerator%20Technical%20Risks%20ISDC07.pdf
and for an improved version, check
http://www.galcit.caltech.edu/~jeshep/icders/cd-rom/EXTABS/178_20TH.PDF
<http://www.galcit.caltech.edu/%7Ejeshep/icders/cd-rom/EXTABS/178_20TH.PDF>
A
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