A French startup developing optical communications systems for spacecraft and other industries has raised 8 million euros ($8.8 million) from a mix of venture capital firms and the French government. Cailabs, a Rennes, France-based company founded in 2013, says it has developed a technology that controls the shape of light within optical fibers, enabling a thousandfold increase in data speeds.
are any of these technologies mature enough for Luna-Earth communication?what about Mars-Earth communication?I don't mean "one Starlink at Mars talking to one Starlink at Earth"; more like "10x or 100x version of the optical interconnects made by these companies". Maybe 10x at Mars/Luna and 1000x in Earth orbit?( aka "Laser Cannon" )
Quote from: dchenevert on 11/20/2021 08:12 pmare any of these technologies mature enough for Luna-Earth communication?what about Mars-Earth communication?I don't mean "one Starlink at Mars talking to one Starlink at Earth"; more like "10x or 100x version of the optical interconnects made by these companies". Maybe 10x at Mars/Luna and 1000x in Earth orbit?( aka "Laser Cannon" )You really only need one station with three transceivers (one active, one to track to the next GEO satellite, one backup) on the lunar surface capable of hitting a GEO satellite. The multi-lambda beam can carry as much data as needed. The lunar users can then use systems with lower mass to communicate with the lunar transceiver with no need to accurately track a GEO satellite. Such a lunar transceiver station is well within today's technology. I'm not so sure about Mars, but the same approach will work better than trying for a separate laser link from each mobile station in Martian space. The big problem will be communicating all that bandwidth from GEO to the Earth's surface.
Quote from: DanClemmensen on 11/20/2021 08:42 pmQuote from: dchenevert on 11/20/2021 08:12 pmare any of these technologies mature enough for Luna-Earth communication?what about Mars-Earth communication?I don't mean "one Starlink at Mars talking to one Starlink at Earth"; more like "10x or 100x version of the optical interconnects made by these companies". Maybe 10x at Mars/Luna and 1000x in Earth orbit?( aka "Laser Cannon" )You really only need one station with three transceivers (one active, one to track to the next GEO satellite, one backup) on the lunar surface capable of hitting a GEO satellite. The multi-lambda beam can carry as much data as needed. The lunar users can then use systems with lower mass to communicate with the lunar transceiver with no need to accurately track a GEO satellite. Such a lunar transceiver station is well within today's technology. I'm not so sure about Mars, but the same approach will work better than trying for a separate laser link from each mobile station in Martian space. The big problem will be communicating all that bandwidth from GEO to the Earth's surface.There are efforts underway to try to enable timeshare lasercomm ground station networks. An obvious problem is that those ground stations want to be in the same places as high altitude astronomical observatories, which is going to end up with some fighting in certain frequencies/bands, as atmospheric windows limits your usable optical bands to begin with.
Here's the slightly easier to read/view Google Patents link for that patent, US 9866324, for a daisychained tethered kytoon setup to support a high altitude air-to-space lasercomm FSO terminal.https://patents.google.com/patent/US9866324B2/en?oq=9%2c866%2c324Kytoons are basically blimps with wings (usually fabric) operating in a kite fashion, using wind to provide some level of lift. At higher altitudes there is a fair amount of wind available usually.This would be an alternative to traditional untethered high altitude balloons, such as those operated by the now defunct Google Loon. Loon demonstrated lasercomm between Loon balloons, and with a combination of accurate high altitude weather mapping and variable air ballast (allowing endless altitude changes without expending fixed ballast, which is sometimes achieved by hanging an inflated air bag underneath giving a distinctive hourglass silhouette), Google could keep a Loon balloon roughly in the same operating area by taking advantage of differing wind directions at different altitudes, theoretically giving them foreverflyer capabilities. While Loon was doing inter-balloon lasercomm, the same basic principles apply to using Loon balloons as HAPS lasercomm relays (as an alternative to more traditional HALE UAV's like Zephyr (or the now defunct Google or Facebook HALE HAPS UAV's)
Quote from: Asteroza on 11/24/2021 09:50 pmHere's the slightly easier to read/view Google Patents link for that patent, US 9866324, for a daisychained tethered kytoon setup to support a high altitude air-to-space lasercomm FSO terminal.https://patents.google.com/patent/US9866324B2/en?oq=9%2c866%2c324Kytoons are basically blimps with wings (usually fabric) operating in a kite fashion, using wind to provide some level of lift. At higher altitudes there is a fair amount of wind available usually.This would be an alternative to traditional untethered high altitude balloons, such as those operated by the now defunct Google Loon. Loon demonstrated lasercomm between Loon balloons, and with a combination of accurate high altitude weather mapping and variable air ballast (allowing endless altitude changes without expending fixed ballast, which is sometimes achieved by hanging an inflated air bag underneath giving a distinctive hourglass silhouette), Google could keep a Loon balloon roughly in the same operating area by taking advantage of differing wind directions at different altitudes, theoretically giving them foreverflyer capabilities. While Loon was doing inter-balloon lasercomm, the same basic principles apply to using Loon balloons as HAPS lasercomm relays (as an alternative to more traditional HALE UAV's like Zephyr (or the now defunct Google or Facebook HALE HAPS UAV's)The "Stratovine" (a chain of tethered kytoons as described in the patent) puts a set of FSO lasers above almost the entire atmosphere and connects them via a fiber-optic cable in the tether to the ground. This gets around the need for a radio link. The radio spectrum is quite limited, but not the optical spectrum. Note that the patent looks like something a non-expert could have put together in 2013 in about three months of surfing the net but it just might work. The patent is oriented toward replacing the teleport links for GEO satellites. A big modern GEO satellite needs multiple geographically-separated teleport links (as many as eight) to support all of its bandwidth. The separation permits it to use the same spectrum via spatial separation. That same satellite can use one FSO laser link to handle far more bandwidth. For use in the lunar or Mars case. I would use the Stratovine to communicate to a GEO satellite that acts as a relay for the Mars or Lunar link, because it will be easier to hit the GEO satellite from the moon or Mars than trying to hit the Stratovine.Note that the kytoons described in the patent do not have wings. Instead, they are balloons with dynamically-adjustable shapes and volumes that act as lifting bodies when that is wind and as balloons when there is no wind.
