Starlink kremlinology - laser terminals
Although initial version of Starlink (1.0) was announced as not being supported, on closer inspection of available drawings and images there are a several places which do seem like a small scape optical terminals.
One of them is placed next to the star tracker, and the schema shows to share similar eletric/signalling wiring connector as star tracker and other antennae.
But that is not all. Each Starlink features three round cylinders, which are probably stiff stand-off structures used to stack the satellites on each other in the launch configuration.
The small instrument next to it seem like a laser source. Although the previous diagram does not show any wiring, on the following diagrams they seem to be connected.
So it is quite likely that even initial Starlink satellites are equipped with optical receivers and laser transmitters for inter-satellite communication. Whether they are test or production ready is not clear. But SpaceX is known to use FPGAs and the processing software/configurable hardware is probably the critical path for this type of application. Optical instruments, and transceivers are probably based on the off-the shelf hardware (much like the hardware used on Lunar Laser Communication Demonstration on LADEE misson.
Testing inter-satellite links will require more densely populated network of satellites. Initial constellation (using just 1580 satellites), will have average satellite distance around 600 km, which will be reduced to just 300 km once initial constellation of 4400 satellites is completed. Rather small optical apertures (which seem to be less than 5 cm) seem to be the limiting factor for the speed of transmission. I do expect that optical instruments will have quite large field of view, in order to minimize movable parts and put constraints on relative positions of satellites in the same orbit. So I do expect that Starlink might employ some kind of store-and-forward packet networking techniques and also highly dynamic (but predictable) packet routing. Combined with phased array antennae, Starlink will require massive onboard computing power and memory resources, reconfigurable through application of FPGA design for most computing intensive functions.
One of them is placed next to the star tracker, and the schema shows to share similar eletric/signalling wiring connector as star tracker and other antennae.
But that is not all. Each Starlink features three round cylinders, which are probably stiff stand-off structures used to stack the satellites on each other in the launch configuration.
The small instrument next to it seem like a laser source. Although the previous diagram does not show any wiring, on the following diagrams they seem to be connected.
So it is quite likely that even initial Starlink satellites are equipped with optical receivers and laser transmitters for inter-satellite communication. Whether they are test or production ready is not clear. But SpaceX is known to use FPGAs and the processing software/configurable hardware is probably the critical path for this type of application. Optical instruments, and transceivers are probably based on the off-the shelf hardware (much like the hardware used on Lunar Laser Communication Demonstration on LADEE misson.
Testing inter-satellite links will require more densely populated network of satellites. Initial constellation (using just 1580 satellites), will have average satellite distance around 600 km, which will be reduced to just 300 km once initial constellation of 4400 satellites is completed. Rather small optical apertures (which seem to be less than 5 cm) seem to be the limiting factor for the speed of transmission. I do expect that optical instruments will have quite large field of view, in order to minimize movable parts and put constraints on relative positions of satellites in the same orbit. So I do expect that Starlink might employ some kind of store-and-forward packet networking techniques and also highly dynamic (but predictable) packet routing. Combined with phased array antennae, Starlink will require massive onboard computing power and memory resources, reconfigurable through application of FPGA design for most computing intensive functions.
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