What you have described includes Roger Angel's proposal to launch remote controlled refractors from the surface of the Earth to the L1 point. All of these ideas involve advanced technologies most likely not available until the second half of the 21st century. Think about how primitive the ISS and its associated delivery systems are and the difficulty with launching and controlling satellites is today. I hadn't seen the idea of increasing the amount of sunlight reaching the Earth before as almost all of the current discussion is on reducing sunlight. Boosting the solar radiation could be helpful in terraforming other planets or moons and longer term may play an important role in colonization of these worlds. What we learn from geoengineering to stop global warming may pay dividends for thousands of years.
On Apr 21, 9:17 am, John Hampson <[email protected]> wrote: > The idea of reflecting sunlight using mirrors at the Earth-Sun L1 > Lagrange point is well established. It appears to be based on > manufacturing mirrors on the Moon from refined regolith and launching > them for assembly at L1: this is to reduce the launch costs of a > massive mirror. > > But has consideration been given to launching very low mass mirrors > directly from Earth? Many large mirrors (say 100m diameter) made from > thin reflective sheet (like space blanket) could be launched directly > from Earth. The problems arise when you try to wallpaper a vacuum > with them and then maintain their shape, orientation and position. > > A rotating space-station, similar to the one in the film 2001 could be > used for this purpose. The sheet would be unfurled across the sunward > face of the space station and the rotational forces would stretch and > maintain the mirrors shape, keeping it rigid. Once the mirror was > stable the space station would detach and move on to the next piece of > vacuum to be wallpapered, leaving hundreds of spinning mirrors in its > wake. > > Two types of mirror might be considered. A “passive mirror” would > float away to be recovered and reused once out of position. To > maintain its orientation it could be convex shaped against the solar > wind and it might initially be launched against the solar wind using > puffs of thruster gas from the space station to extend its life. > > A better option would involve an “active mirror” having a number of > solar-powered miniature ion-thrusters installed around its outer > edge. These would maintain the mirrors rotation, orientation and > position in space. This would avoid (or at least reduce) the > hazardous activity of recovering out of position mirrors. > > Active mirrors would be flexible because they could be remote- > controlled and might be useful in Earth orbit to reduce warming, > manipulate the weather and even replace street lighting in urban > areas. At Lagrange points L4 and L5 they could reflect sunlight > towards Earth in the event of cooling brought on by natural disaster > (volcanic eruption or asteroid impact). > > A spinning Earth orbit space station built for scientific purposes > could include facilities to unfurl mirrors at relatively little extra > cost. An entire fleet of low mass mirrors sent to this station might > require less launch mass than is needed just to build a Moon base and > could be a flexible and relatively low cost means to control global > warming. > > John Hampson --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
