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 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 A -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
