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I wonder what plans they have for communicating with a probe light-years away. Consider New Horizons. It has a power budget and antenna gain way beyond somethin
by avian 11y ago
I wonder what plans they have for communicating with a probe light-years away. Consider New Horizons. It has a power budget and antenna gain way beyond something that can be crammed into a few grams. Yet, the bit rate is so low it's still sending back data it gathered in 2015 from an encounter mere light-hours away.
Even if the laser propulsion aspect of this works out, I think communicating with something that far away is fantastically beyond state-of-the-art in wireless communications.
- nilstycho 11y ago“Images of the target planet could be transmitted by a 1Watt laser onboard the nanocraft, in a ‘burst mode’ which uses the energy storage unit to rapidly draw power for the power-intensive laser communications mode. Upon approach to the target, the sail would be used to focus the laser communication signal. “For a 4m sail, for example, the diffraction limit spot size on Earth would be on order of 1000m. A kilometer-scale receiving array would intercept 10-14 of the transmitted signal. The main challenge is to use the sail as diffraction limited optics for the laser communication system. This would be achieved by shaping the sail into a ‘Fresnel lens’ upon approach to the target. The sail structure could be different at the launch and communication phases. In order to maintain a high transmission through the Earth’s atmosphere, the communication would need to operate at a wavelength shorter than that used by the launch laser system, due to the Doppler shift of the nanocraft relative to the Earth.” http://breakthroughinitiatives.org/index.php?controller=Forum&action=viewforum&id=13&page=1 http://breakthroughinitiatives.org/index.php?controller=Foru...
- throwaway_yy2Di 11y ago"For a 4m sail, for example, the diffraction limit spot size on Earth would be on order of 1000m." That must be a misprint; the diffraction-limited spot size would be on the order of 10 million kilometers. It's correct when it says a 1 km^2 collector would intercept ~10^{-14} of the transmitted signal. https://www.google.com/search?q=4+light+years+*+1+micron+%2F+4+meters https://www.google.com/search?q=4+light+years+*+1+micron+%2F... https://en.wikipedia.org/wiki/Airy_disk#Size https://en.wikipedia.org/wiki/Airy_disk#Size
- mafribe 11y agoVince Cerf is working on interstellar communication: http://www.icarusinterstellar.org/vint-cerf-qa-on-interstellar-communication/ http://www.icarusinterstellar.org/vint-cerf-qa-on-interstell...
- dllthomas 11y agoWhile Vince is a much more common name, the man in question is named Vinton (commonly shortened to Vint).
- tim333 11y agoYou could write a note on the sail to any aliens at Alpha Centauri asking them to call back.