Re: [geo] Stratospheric aerosol injection tactics and costs in the first 15 years of deployment - IOPscience

[Andrew Lockley]

As far as I know, the cost cliffs at the limit of air-breathing engines
(with reasonable payloads). As discussed elsewhere on the thread, there are
a number high-ceiling techs: hybrid engines, reusable rockets, and guns.
All are likely to be more expensive/uncertain, medium term.



On Sun, 6 Jan 2019, 22:34 Douglas MacMartin  Haven’t read through all of this exchange carefully yet, but just a
> comment that, provided we have time (and research funding) between now and
> deployment, it would be good to understand the cost vs altitude trade
> moderately well, both on the deployment cost side, and on the climate
> side-effect side.
>
>
>
> If, for example, 23km is 10x more expensive than 22km, we ought to know
> that when doing climate model simulations.  Though, even if that were true,
> we should still consider simulations across a range of altitudes.
>
>
>
> Buried in all of this is that we’re doing research for a subject without
> knowing the timeline we need to meet for the outcomes of that research…
> what one might do deployment-wise if someone wanted to start deploying in
> 2025 might be very different if that year was 2040.  (And there’s a
> reasonable argument for being prepared for a range of possible answers to
> the timeframe question.)
>
>
>
> d
>
>
>
> *From:* geoengineering@googlegroups.com [mailto:
> geoengineering@googlegroups.com] *On Behalf Of *Andrew Lockley
> *Sent:* Sunday, January 06, 2019 5:26 PM
> *To:* Wake Smith 
> *Cc:* geoengineering 
> *Subject:* Re: [geo] Stratospheric aerosol injection tactics and costs in
> the first 15 years of deployment - IOPscience
>
>
>
> Wake
>
>
>
> Thanks for your detailed response.
>
>
>
> As regards hybrid engines, I can't comment on the costs or the airframe
> requirements - but I suspect it would be worth a look. One benefit is that
> it would allow the use of off-the-shelf engines, thus cutting dev costs.
> These are frontloaded and uncertain, as you point out. The GE/Pratt
> alternatives are also attractive for readiness reasons - but lack the
> attractive additional altitude.
>
>
>
> I would be cautious about specifying short flights. I have seen the new,
> unreleased TU Delft analysis on this, and I don't think that short flights
> are likely to be a universally agreed strategy among the teams working on
> this issue. That's based on the (English?) work on vapour condensation
> delivery. The key variable is that dropping acid is far more mass efficient
> than ambient condensation, due to monodisperse particle size distribution.
> It therefore (likely) reduces O3 loss and rain out pollution, too.
>
>
>
> I don't agree with your assessment of gun tech. Railguns are under active
> development by both the US and China (although these are unsuitable for
> Geoengineering). A more suitable technology is the gas gun. Quicklaunch and
> Utron (both now in the deadpool) have worked on this. Utron actually got a
> prototype working. The benefit of gas guns is that velocities aren't
> subject to any obvious technological limitation (even up to LEO), so
> injection can be as high as you like. This trades off against mass flux,
> due to the efficiencies discussed earlier. Faster splashdown would make
> shell recovery and refurbishment more difficult, though.
>
>
>
> As regards SpaceX, I think you're at risk of comparing apples with
> oranges. Their intention is to compete with airliners (including supersonic
> ones from eg Boom), so they're likely going to be 1-2 orders cheaper for
> suborbital than for space launch.
>
>
>
> Happy to discuss further, if you have more to add.
>
>
>
> Andrew
>
>
>
>
>
>
>
>
>
>
>
> On Sun, 6 Jan 2019, 21:23 Wake Smith 
> Dear Andrew (& group),
>
> Firstly, thank you for the thorough and thoughtful questions.  I am happy
> to dig in further on these details with knowledgeable correspondents.
> Secondly, I should note that I do NOT consider this paper to have been the
> final and definitive word on early deployment tactics, but rather simply
> (and hopefully) a forward step from the essential work done earlier by
> McClellan et al and others.  “McClellan” (as I will hereinafter refer to
> their paper) remains foundational and I started my explorations by meeting
> with both McClellan and Keith and picking up the ball where they laid it.
> I am comfortable with our paper insofar as it went, but I acknowledge there
> to be many yet still unanswered questions which I intend to address in
> subsequent undertakings.  Thirdly, I am speaking here only for myself,
> though Gernot will undoubtedly weigh in additionally as he sees fit.
>
> Starting with your “Tilmes +5k” question, I should note that our paper
> diverged from McClellan at the outset by choosing a specific mission and
> then considering platforms to fulfill that mission and only that mission.
> McClellan on the other hand considered deployment altitudes ranging from 18
> – 30 kms, targeting the lower part (18 – 25kms) of that range.  Table 2
> surveys an even wider range, 

RE: [geo] Stratospheric aerosol injection tactics and costs in the first 15 years of deployment - IOPscience

[Douglas MacMartin]

Haven’t read through all of this exchange carefully yet, but just a comment 
that, provided we have time (and research funding) between now and deployment, 
it would be good to understand the cost vs altitude trade moderately well, both 
on the deployment cost side, and on the climate side-effect side.

If, for example, 23km is 10x more expensive than 22km, we ought to know that 
when doing climate model simulations.  Though, even if that were true, we 
should still consider simulations across a range of altitudes.

Buried in all of this is that we’re doing research for a subject without 
knowing the timeline we need to meet for the outcomes of that research… what 
one might do deployment-wise if someone wanted to start deploying in 2025 might 
be very different if that year was 2040.  (And there’s a reasonable argument 
for being prepared for a range of possible answers to the timeframe question.)

d

From: geoengineering@googlegroups.com [mailto:geoengineering@googlegroups.com] 
On Behalf Of Andrew Lockley
Sent: Sunday, January 06, 2019 5:26 PM
To: Wake Smith 
Cc: geoengineering 
Subject: Re: [geo] Stratospheric aerosol injection tactics and costs in the 
first 15 years of deployment - IOPscience

Wake

Thanks for your detailed response.

As regards hybrid engines, I can't comment on the costs or the airframe 
requirements - but I suspect it would be worth a look. One benefit is that it 
would allow the use of off-the-shelf engines, thus cutting dev costs. These are 
frontloaded and uncertain, as you point out. The GE/Pratt alternatives are also 
attractive for readiness reasons - but lack the attractive additional altitude.

I would be cautious about specifying short flights. I have seen the new, 
unreleased TU Delft analysis on this, and I don't think that short flights are 
likely to be a universally agreed strategy among the teams working on this 
issue. That's based on the (English?) work on vapour condensation delivery. The 
key variable is that dropping acid is far more mass efficient than ambient 
condensation, due to monodisperse particle size distribution. It therefore 
(likely) reduces O3 loss and rain out pollution, too.

I don't agree with your assessment of gun tech. Railguns are under active 
development by both the US and China (although these are unsuitable for 
Geoengineering). A more suitable technology is the gas gun. Quicklaunch and 
Utron (both now in the deadpool) have worked on this. Utron actually got a 
prototype working. The benefit of gas guns is that velocities aren't subject to 
any obvious technological limitation (even up to LEO), so injection can be as 
high as you like. This trades off against mass flux, due to the efficiencies 
discussed earlier. Faster splashdown would make shell recovery and 
refurbishment more difficult, though.

As regards SpaceX, I think you're at risk of comparing apples with oranges. 
Their intention is to compete with airliners (including supersonic ones from eg 
Boom), so they're likely going to be 1-2 orders cheaper for suborbital than for 
space launch.

Happy to discuss further, if you have more to add.

Andrew





On Sun, 6 Jan 2019, 21:23 Wake Smith 
mailto:w...@crowsven.com> wrote:
Dear Andrew (& group),
Firstly, thank you for the thorough and thoughtful questions.  I am happy to 
dig in further on these details with knowledgeable correspondents.  Secondly, I 
should note that I do NOT consider this paper to have been the final and 
definitive word on early deployment tactics, but rather simply (and hopefully) 
a forward step from the essential work done earlier by McClellan et al and 
others.  “McClellan” (as I will hereinafter refer to their paper) remains 
foundational and I started my explorations by meeting with both McClellan and 
Keith and picking up the ball where they laid it.  I am comfortable with our 
paper insofar as it went, but I acknowledge there to be many yet still 
unanswered questions which I intend to address in subsequent undertakings.  
Thirdly, I am speaking here only for myself, though Gernot will undoubtedly 
weigh in additionally as he sees fit.
Starting with your “Tilmes +5k” question, I should note that our paper diverged 
from McClellan at the outset by choosing a specific mission and then 
considering platforms to fulfill that mission and only that mission.  McClellan 
on the other hand considered deployment altitudes ranging from 18 – 30 kms, 
targeting the lower part (18 – 25kms) of that range.  Table 2 surveys an even 
wider range, from  as low as 40kft (~12.2 km) up to 100 kft (~30 km).  So wide 
a spectrum of possible injection altitudes naturally leads to a wide variety of 
platforms suitable to address at least some of the part of that spectrum and 
contributed to an impression that there were many ways to “skin the cat” as it 
were.  More specifically, this implied that some sub-stratospheric altitudes 
were nonetheless acceptable for deployment even though the text of the paper 
called for 

Re: [geo] Stratospheric aerosol injection tactics and costs in the first 15 years of deployment - IOPscience

[Andrew Lockley]

Wake

Thanks for your detailed response.

As regards hybrid engines, I can't comment on the costs or the airframe
requirements - but I suspect it would be worth a look. One benefit is that
it would allow the use of off-the-shelf engines, thus cutting dev costs.
These are frontloaded and uncertain, as you point out. The GE/Pratt
alternatives are also attractive for readiness reasons - but lack the
attractive additional altitude.

I would be cautious about specifying short flights. I have seen the new,
unreleased TU Delft analysis on this, and I don't think that short flights
are likely to be a universally agreed strategy among the teams working on
this issue. That's based on the (English?) work on vapour condensation
delivery. The key variable is that dropping acid is far more mass efficient
than ambient condensation, due to monodisperse particle size distribution.
It therefore (likely) reduces O3 loss and rain out pollution, too.

I don't agree with your assessment of gun tech. Railguns are under active
development by both the US and China (although these are unsuitable for
Geoengineering). A more suitable technology is the gas gun. Quicklaunch and
Utron (both now in the deadpool) have worked on this. Utron actually got a
prototype working. The benefit of gas guns is that velocities aren't
subject to any obvious technological limitation (even up to LEO), so
injection can be as high as you like. This trades off against mass flux,
due to the efficiencies discussed earlier. Faster splashdown would make
shell recovery and refurbishment more difficult, though.

As regards SpaceX, I think you're at risk of comparing apples with oranges.
Their intention is to compete with airliners (including supersonic ones
from eg Boom), so they're likely going to be 1-2 orders cheaper for
suborbital than for space launch.

Happy to discuss further, if you have more to add.

Andrew






On Sun, 6 Jan 2019, 21:23 Wake Smith  Dear Andrew (& group),
>
> Firstly, thank you for the thorough and thoughtful questions.  I am happy
> to dig in further on these details with knowledgeable correspondents.
> Secondly, I should note that I do NOT consider this paper to have been the
> final and definitive word on early deployment tactics, but rather simply
> (and hopefully) a forward step from the essential work done earlier by
> McClellan et al and others.  “McClellan” (as I will hereinafter refer to
> their paper) remains foundational and I started my explorations by meeting
> with both McClellan and Keith and picking up the ball where they laid it.
> I am comfortable with our paper insofar as it went, but I acknowledge there
> to be many yet still unanswered questions which I intend to address in
> subsequent undertakings.  Thirdly, I am speaking here only for myself,
> though Gernot will undoubtedly weigh in additionally as he sees fit.
>
> Starting with your “Tilmes +5k” question, I should note that our paper
> diverged from McClellan at the outset by choosing a specific mission and
> then considering platforms to fulfill that mission and only that mission.
> McClellan on the other hand considered deployment altitudes ranging from 18
> – 30 kms, targeting the lower part (18 – 25kms) of that range.  Table 2
> surveys an even wider range, from  as low as 40kft (~12.2 km) up to 100 kft
> (~30 km).  So wide a spectrum of possible injection altitudes naturally
> leads to a wide variety of platforms suitable to address at least some of
> the part of that spectrum and contributed to an impression that there were
> many ways to “skin the cat” as it were.  More specifically, this implied
> that some sub-stratospheric altitudes were nonetheless acceptable for
> deployment even though the text of the paper called for injection above the
> tropopause.  From the standpoint of the grubby aviation guys simply trying
> to fly the mission, altitude is the critical parameter here, so more
> specificity was required in order to zero in on a platform choice.  We
> therefore chose to define a much more specific mission that always deployed
> well into the stratosphere, which in turn led us to a more specific
> platform recommendation.  The mission we chose was injections as high as
> 65k ft (~20km), and we sourced this mission requirement from
> MacMartin/Tilmes/Kravitz.  To be clear, this does not mean that all
> injections would necessarily achieve this altitude – one might choose lower
> on particular days and at higher latitudes – but the maximum injection
> altitude anywhere defines the altitude threshold for the platform design.
> So, why didn’t we consider the engine alternative you note?  Because it was
> not necessary to achieve the defined mission.
>
> The above of course begs the question as to whether we chose the right
> mission, or whether we should have instead chosen various alternative
> missions, such as the “+5k” alternative.  As regards the mission we chose,
> we had to start somewhere, and this seemed (and still does seem) like the
> 

Fwd: [geo] Stratospheric aerosol injection tactics and costs in the first 15 years of deployment - IOPscience

[Andrew Lockley]

-- Forwarded message -
From: Wake Smith 
Date: Sun, 6 Jan 2019, 21:23
Subject: RE: [geo] Stratospheric aerosol injection tactics and costs in the
first 15 years of deployment - IOPscience
To: Andrew Lockley 
Cc: geoengineering 


Dear Andrew (& group),

Firstly, thank you for the thorough and thoughtful questions.  I am happy
to dig in further on these details with knowledgeable correspondents.
Secondly, I should note that I do NOT consider this paper to have been the
final and definitive word on early deployment tactics, but rather simply
(and hopefully) a forward step from the essential work done earlier by
McClellan et al and others.  “McClellan” (as I will hereinafter refer to
their paper) remains foundational and I started my explorations by meeting
with both McClellan and Keith and picking up the ball where they laid it.
I am comfortable with our paper insofar as it went, but I acknowledge there
to be many yet still unanswered questions which I intend to address in
subsequent undertakings.  Thirdly, I am speaking here only for myself,
though Gernot will undoubtedly weigh in additionally as he sees fit.

Starting with your “Tilmes +5k” question, I should note that our paper
diverged from McClellan at the outset by choosing a specific mission and
then considering platforms to fulfill that mission and only that mission.
McClellan on the other hand considered deployment altitudes ranging from 18
– 30 kms, targeting the lower part (18 – 25kms) of that range.  Table 2
surveys an even wider range, from  as low as 40kft (~12.2 km) up to 100 kft
(~30 km).  So wide a spectrum of possible injection altitudes naturally
leads to a wide variety of platforms suitable to address at least some of
the part of that spectrum and contributed to an impression that there were
many ways to “skin the cat” as it were.  More specifically, this implied
that some sub-stratospheric altitudes were nonetheless acceptable for
deployment even though the text of the paper called for injection above the
tropopause.  From the standpoint of the grubby aviation guys simply trying
to fly the mission, altitude is the critical parameter here, so more
specificity was required in order to zero in on a platform choice.  We
therefore chose to define a much more specific mission that always deployed
well into the stratosphere, which in turn led us to a more specific
platform recommendation.  The mission we chose was injections as high as
65k ft (~20km), and we sourced this mission requirement from
MacMartin/Tilmes/Kravitz.  To be clear, this does not mean that all
injections would necessarily achieve this altitude – one might choose lower
on particular days and at higher latitudes – but the maximum injection
altitude anywhere defines the altitude threshold for the platform design.
So, why didn’t we consider the engine alternative you note?  Because it was
not necessary to achieve the defined mission.

The above of course begs the question as to whether we chose the right
mission, or whether we should have instead chosen various alternative
missions, such as the “+5k” alternative.  As regards the mission we chose,
we had to start somewhere, and this seemed (and still does seem) like the
right place to initially plant the stake, in part because it was based upon
such a well-respected prior paper.  That said, one of my personal projects
for 2019 is to drill down further on the question of necessary deployment
altitude to further clarify the dynamics that define both the release
altitude and the migration of the material after release, so more to come
on this.  However, the primary question I am pursuing there is whether we
can in fact deploy LOWER, not higher.  I am mindful of the ~50% further
radiative benefit that Simone notes would be achieved by an additional 5k
of altitude, but that seems somewhat marginal on top of the ~50X benefit we
achieve by ensuring we are in the stratosphere rather than the troposphere,
and that 5k would come at a very high cost.  You imply that one could get
there by simply strapping different powerplants on the wings, but I highly
doubt that.  20 kms is the ragged edge of what can be achieved with
traditional fixed wing, self-propelled aircraft – none of the Global
Hawk/U2/SR-71/WB-57 get materially higher than that, and each of those with
a mere ~1 ton payload.  Getting 25 tons up to 20 kms would be
unprecedented, though achievable, I believe.  Getting up to 25kms WITH A
HEAVY PAYLOAD (please don’t send me artwork of the Perlan and such) means
we are no longer flying aircraft, but moving to other platform types that
we have demonstrated come with a minimum 10X cost differential.  10X more
cost to get 0.5X more benefit doesn’t seem like a sensible trade – BUT, if
someone knows something I don’t, please advise (I will stop repeating this,
but this sentiment is general to the dialogue here).

I don’t share your understanding that mid-air refueling would be cheaper
option – quite the opposite.  Mid-air 

[geo] My nutty idea ...

[Michele , Jürgen]

Hi all!


By now the decade is over ...


See attachement!


Greetings and best wishes for the new year



Juergen




Prof. Dr.-Ing. Juergen Michele
Jade Hochschule
Wilhelmshaven

Tel.: 0049 4461 83043
E-Mail:juergen.mich...@jade-hs.de
Homepage: http://michele.staff.jade-hs.de/
https://www.researchgate.net/profile/Juergen_Michele/contributions

Privat:
Soestestr. 3
26419 Schortens

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Another nutty idea or Modeller wanted.docx
Description: Another nutty idea or Modeller wanted.docx