Hi, there, everybody and greetings from Dar es Salaam. I'm here in Tanzania on a geothermal job.
Over a year ago, I posted a PDF of the full paper from JBIS to this group, but no comment ensued. Look for the keywords "Dyson Dots". We (R.G.Kennedy, E.Hughes, K.I. Roy, D.E.Fields) have been working on this for ~16 years, and published in Acta Astronautica, JBIS, the Russian Academy of Sciences/Rosgidromet, Stanford's EE380 lecture series, Asilomar, and many other venues. A couple months ago, Mr. Bart Leahy reached out to us to do a more popular treatment of the subject. Yes, Dr. McCracken, Jim Early is fully aware of our work and was in my living room in Oak Ridge TN two years ago in November 2014, where he got to meet all the authors of that latest version "Dyson Dots". It was on the 25th anniversary, to the hour, of the Wall coming down. Kinda cool evening, that. A couple important points about orbital dynamics, and one about cost, that Mr. Leahy didn't have room to cover in a mere 1000-word limit: (1) a fleet of sunshades is not *at* L1, they go around the Sun in "radiation-levitated non-Keplerian orbits" significantly inside of L1, 1-2 million km depending on their specific mass density [kg/m^2]. The lighter a sunshade-sail is, the further inside it has to go. Wherever that point is, four forces in metastable balance: the two opposing gravitational pulls of the Earth and the Sun, the centripetal force of the shade's path around the Sun, and light pressure. (2) L1, L2, and L3, and the regions of space near them, are metastable, not truly stable like L4 and L5. Therefore, the sunshade must continually monitor and adjust its position, by modulating light pressure. The Japanese IKAROS sail of 2010? showed that that is possible. (3) Using the space launch methods that we are limited to today, and building a fleet of shades big enough to do the job (collective shading area is the size of Texas, mass of a good 100 megatonnes) with only terrestrial resources, would be fabulously expensive. Multiples of gross world product. Therefore, either these things get built in space with offworld materials, or they don't get built at all. Most geoengineering schemes are invoked by some kind of fiat. The clean-power-from-space facet of Dyson Dots is a way we proposed for the scheme to organically pay for itself. HELIOS is just the sunshading part, i.e., Dyson Dots with the space-based power element removed. Robert G. Kennedy III, PE www.ultimax.com 1994 AAAS/ASME Congressional Fellow U.S. House Subcommittee on Space On Monday, December 12, 2016 at 1:58:24 PM UTC-5, Andrew Lockley wrote: > > > http://www.spaceflightinsider.com/missions/commercial/researchers-investigating-large-sunshades-combat-global-warming/ > > > RESEARCHERS INVESTIGATING LARGE SUNSHADES TO COMBAT GLOBAL WARMING > > BART LEAHY > DECEMBER 11TH, 2016 > > A group of concerned engineers and scientists is investigating a > space-based method to offset global warming. Their concept is called > Heliocentric Earth-Lagrangian Interception of Sunlight (HELIOS), a > flotilla of perhaps many thousands of kilometer-square sun sails that, > once placed at the Sun-Earth Lagrange (SEL1) point, would reduce the > amount of sunlight striking the Earth. > > THINKING BIG > > ________________________________ > > HELIOS was born out of a pair of papers presented at the Tennessee > Valley Interstellar Workshop (TVIW) and later in the Journal of the > British Interplanetary Society (JBIS). Those papers focused on > geoengineering, the deliberate large-scale modification of the Earth’s > climate through artificial means. Arguably, human beings have already > been performing accidental geoengineering over the last 200 years by > increasing the amount of carbon dioxide in the atmosphere through > burning fossil fuels. > > The paper presenter, Robert G. Kennedy III, proposed building “Dyson > Dots” – a much smaller version of a conceptual swarm of solar > collectors proposed by physicist Freeman Dyson to capture the entire > energy output of a star, now called a “Dyson Sphere”. > > These “dots” would consist of multiple reflectors and block an area > approximately 386,000 square miles (over 1,000,000 square kilometers) > in extent, nearly the size of the state of Texas. The reflectors would > be placed near L1 to ensure a stable orbit. At this distance, the Dot > would reduce the amount of sunlight (insolation) the Earth receives by > as much as one-quarter of one percent. Is that enough to make a > difference? Kennedy and the other members of the HELIOS team think so. > > image: > http://www.spaceflightinsider.com/wp-content/uploads/2016/12/L1-Positioning-655x346-1.png > > > Large sunshades placed at the Sun-Earth Lagrange Point 1 (L1 in this > image) could reduce the amount of sunlight Earth receives by just > enough to offset any effects caused by global warming. Image Credit: > R. Kennedy / Ultimax Group and D. Hughes / www.debbiehughes.com > > “This reduction would bring down Earth’s average global temperature by > as much as 2.7 degrees Fahrenheit (1.5 degrees Celsius), approximately > the same change that brought about the “Little Ice Age” (approximately > 1550–1850 C.E.).” > > The goal is not to produce an ice age. Instead, HELIOS would combat > the anticipated global temperature rise by precisely offsetting it > with artificial cooling. > > THE BIG PICTURE > > ________________________________ > > “The initial study assumed the shade just appeared, all in one piece,” > Kennedy explained. “In reality, it will be assembled from smaller > sunshades. Nobody’s going to build a 100-megatonne piece of tinfoil > the size of Texas in one go, especially the first time. An actual > project would be incrementally built, incrementally deployed, incur > [an] incremental expense, and yield incremental benefits.” > > In the long term, learning to build megastructures like the Dyson Dot > would advance the progress of solar-sail propulsion. Solar sails are > one possible method of transport within the solar system and to other > stars. > > “Also, we’re certain the sunshades would have to be manufactured in > space, with off-world resources,” Kennedy said. > > HELIOS could spur the in-space economy, as it will require access to > in situ magnesium – which is three times more common off Earth than > aluminum – as well as silicon, carbon, and iron. In addition to > resources, of course, the array requires advanced, industrial-scale > in-space manufacturing capabilities. > > Lastly, a Dyson Dot could act like a conventional household or > satellite solar panel, converting solar radiation into electricity. > The solar energy collected from the Dyson Dot network could be > transmitted to Earth through space via a series of relays, supplying > over 10,000 gigawatts per year – Earth’s entire electric power demand. > > Before that, HELIOS, the first-generation sunshield without the power > generation capability, has to help address the global warming problem. > > HELIOS’ NEXT STEPS > > ________________________________ > > Obviously, a project as ambitious as HELIOS will be difficult and > expensive, so the group’s initial priority will be financing. This > means attracting the interest of venture capitalists or angel > investors as well as getting their ideas into the public consciousness > (full disclosure: the author of this article is the HELIOS team’s > outreach consultant). > > Technically, the initial steps for developing HELIOS will include > defining the system architecture, defining its physical > characteristics, and determining its actual environmental performance. > The team will also need to do a due-diligence review on the system. > For example, they must determine the Technology Readiness Level (TRL) > of the major system components and develop a roadmap for development > and TRL advancement. > > Along the way, the team will develop multiple deployment strategies > for the sunshade, looking for incremental, affordable ways to do it. > Once the high-level strategizing is complete, the HELIOS team will > focus on developing proof-of-concept technologies, such as packaging > and deployment mechanisms for large-scale solar sails. And – of > interest to any investors – they need to provide a solid estimate of > benefits, implementation costs, and timeline. > > How much would the overall system cost? That’s one of the things the > initial architecture studies will determine. > > “Odds are, with current lift methods, the cost would be astronomical, > though it would probably still be cheaper than moving everybody on the > seacoasts 50 miles inland as sea levels rise,” said HELIOS team member > Ken Roy. > > A space-based geoengineering solution to global warming could be done > incrementally and, more importantly, could be quickly reversible > should any negative side effects arise along the way. > > Obviously, the HELIOS team is taking the long view, but their proposed > hardware offers the long-term potential to address both global warming > and future energy production. A healthy planet with abundant energy > for future generations, they maintain, would be an excellent return on > investment. > > Individuals interested in working with the HELIOS group can contact > Robert Kennedy or Victoria Coverstone. > > > Read more at > http://www.spaceflightinsider.com/missions/commercial/researchers-investigating-large-sunshades-combat-global-warming/#iy0q5rLvBB60aB7V.99 > > -- 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.
