Breakthrough Starshot

[QueElEs]

That is the clever part. They would (in theory) be able to work together to send coordinated messages back to us, which would be received by the same phased-array emitters that provided the thrust to send them there, only working in reverse. Luke Campbell has pointed out the sort of remarkable things a phased-array emitter-detector system could achieve; this is one of them.

Note, however that none of this technology is available today, and will need several decades of development to make it suitable for interstellar missions. And the same technology that could receive faint messages from a swarm of tiny sails four light-years away would also make a bloody good telescope, probably producing much better information by directly imaging the star (and planets) than by receiving data from a swarm of tinfoil spacecraft cannoning through the system at a significant fraction of light speed.

Perhaps if you had a stream of them heading out there, they could transmit back to Earth as a relay? Not requiring such a powerful detector capacity.

[giulio]

Actually, I believe the issue you raise falls under what they refer to as 'policy issues' (possibly with just a dash of understatement). ...
Todd

I guess the Starshot team will be forced to reconsider the location of the beamer. Which country will accept the responsibility to protect the beamer from terrorists that could use it to shoot planes in the sky, satellites etc.?

I think the option of basing the beamer on the far side of the moon should be considered. It's likely to more than double the overall cost of the project, but the establishment of a moonbase on the far side - which could double as an astronomical observatory and other uses - is a worthy goal in itself and could attract its own funding.

NASA, ESA and other space agencies have preliminary plans for a farside moonbase. While unlikely to significantly contribute to Starshot itself, the space agencies could be persuaded to contribute to the establishment of the moonbase, including transportation. Perhaps Starshot could be the catalyst that makes a moonbase happen.

[iancampbell]

Plans to avoid the issue of danger to passing aircraft and satellites would be made more complicated by the fact that the array would have to be steerable. If it wasn't, it would only be useful for a few seconds to minutes each day, when the rotation of the Earth happened to bring the probe swarm into the right direction.

Building it on the lunar farside would also do three more things; boost effective power (losses in Earth's atmosphere would otherwise be inevitable), avoid focusing and aiming issues caused by atmospheric refraction - and make the laser available as part of an asteroid deflection strategy. If this thing is finely enough focused and aimed to be useful for power transmission at interstellar distances, then it's certainly good enough in those respects to hit an asteroid.

[Ace009]

Gentlemen? Is it just me or am I starting to think Breakthrough: Starshot is being overhyped and will possibly end up like Daedalus, Longshot and Orion before it because of politicians?

[stevebowers]

Interstellar missions of any kind are probably at least a century away; this isn't even on the horizon for most politicians. However when the first boostbeams lasers are being built, we can be fairly sure that some politicians will be apprehensive about them.

[iancampbell]

Interstellar missions of any kind are probably at least a century away; this isn't even on the horizon for most politicians. However when the first boostbeams lasers are being built, we can be fairly sure that some politicians will be apprehensive about them.

In this case, and strictly IMHO, rightly so. At least unless humanity (whatever that means by then) and any other sapients who might be present have grown up a little.