To reply specifically with likely issues : AFAIK the liquid/gas column behaviour in the balloon pipe is problematic. Hugh Hunt (cc) has, I believe, worked on this aspect of the viability. The adiabatic cooling causes a temperature reduction, as the hydrostatic pressure drops. This requires heating to a problematic temperature.
Rail guns are problematic for a range of reasons, not least their lack of development. They are highly prone to wear, and aren't particularly suited to launching large payloads. I've worked on gas guns, which have more suitable performance characteristics. Generally, I don't take the view that engineering is trivial. I think we should engineer early, and with the same enthusiasm as we apply to other aspects. Engineering is trivial when it's done, not when it isn't. A On 16 Oct 2017 18:53, "Douglas MacMartin" <macma...@cds.caltech.edu> wrote: > The start was Andrew’s email, which was based on a presentation given at > CEC17 (sorry, there weren’t any viewgraphs, but you’ve already got the > summary). > > > > There’s nothing inherently “wrong” with any approach. Eventually we’ll > need a more serious engineering analysis of different options (i.e., beyond > speculation). IMHO that day isn’t now, I’m satisfied with knowing that it > is a solvable problem. > > > > Re material, yes, various other materials have definite advantages with > respect to either stratospheric heating or ozone loss. But there’s also a > big advantage with using something that exists naturally in the > stratosphere, as that at least gives an argument for bounding uncertainty. > I think it is rather premature to say one makes “more sense” than another > right now, as there are different (and somewhat non-commensurate) concerns. > > > > *From:* geoengineering@googlegroups.com [mailto:geoengineering@ > googlegroups.com] *On Behalf Of *David Sevier > *Sent:* Monday, October 16, 2017 1:46 PM > *To:* andrew.lock...@gmail.com > *Cc:* 'geoengineering' <geoengineering@googlegroups.com> > *Subject:* RE: [geo] Engineering drama, post CEC > > > > I am struggling to find the beginning of this thread. What are you guys > talking about exactly. What is wrong with pumping up a tube as so many have > suggested or using rail guns to launch packages into the higher atmosphere. > In the latter case, fine particles of chalk (such a PCC) make more sense > than sulphuric acid. > > > > *From:* geoengineering@googlegroups.com [mailto:geoengineering@ > googlegroups.com] *On Behalf Of *Greg Rau > *Sent:* 16 October 2017 17:23 > *To:* andrew.lock...@gmail.com > *Cc:* geoengineering > *Subject:* Re: [geo] Engineering drama, post CEC > > > > But as to the pile of papers, just think of the carbon storage! > > G > > Sent from my iPhone > > > On Oct 15, 2017, at 4:19 PM, Andrew Lockley <andrew.lock...@gmail.com> > wrote: > > From what I gather, it seems we have a bit of engineering drama. > Apparently, you can't just swap aircraft engines and do SRM, because the > wings aren't right on any aircraft with even a vaguely adequate payload. > > > > This is A Problem. > > > > We've either got to > > A) engineer a new aircraft, like the Delft team did (with a $100m expected > development cost) > > B) work out a way to make new wings for an existing jet (not simple) > > C) come up with something else > > > > If we assume it's C, then there's quite a lot decent new hardware around. > One choice is Blue Origin/Space X kit. Does anyone know how that would fare > in an up-and-down flight path? I know Blue Origin did that before. Payload > should be manageable, but I'm not sure how costs are coming down. > > > > Another alternative is one of the hybrid concepts. I got a flea in my ear > for mentioning BAE systems hybrid engines before. However, their power in > thin air may make them suitable for geoengineering use - either as zoom > climbers or cruise. > > > > I know that current thinking is to condense H2SO4 directly, but I guess > with any kind of zoom climb, you're pretty much stuck dumping bulk SO2 and > crossing your fingers it doesn't all coagulate to baseball-size and drop > out! > > > > Would be great to hear from people on the list. > > > > (Personally, my concern is that our best option for accessing the > stratosphere at the current rate of engineering might be to make a large > pile of climate engineering governance papers, and walk up that carrying > gas tanks! There will soon be enough of them ;) ) > > > > Andrew > > > > > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to geoengineering+unsubscr...@googlegroups.com. > To post to this group, send email to geoengineering@googlegroups.com. > Visit this group at https://groups.google.com/group/geoengineering. > For more options, visit https://groups.google.com/d/optout. > > > > [image: Image removed by sender.] > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> > > Virus-free. www.avg.com > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to geoengineering+unsubscr...@googlegroups.com. > To post to this group, send email to geoengineering@googlegroups.com. > Visit this group at https://groups.google.com/group/geoengineering. > For more options, visit https://groups.google.com/d/optout. > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to geoengineering+unsubscr...@googlegroups.com. > To post to this group, send email to geoengineering@googlegroups.com. > Visit this group at https://groups.google.com/group/geoengineering. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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