Laser Powered Sail to get to Proxima b

Is project 'Breakthrough Starshot' just a sc-fi fantasy driven initiative?:

Scientists are developing a laser-powered SAIL to reach Alpha Centauri

The Alpha Centauri star system is 24 trillion miles (4.37 light years) away.

With today's fastest spacecraft, it would take thousands of years to get there.

Breakthrough Starshot aims to establish whether a gram-scale nanocraft, on a sail pushed by a light beam, can fly over a thousand times faster.

Astronomers estimate that there is a reasonable chance of an Earth-like planet existing in the 'habitable zones' of Alpha Centauri's three-star system.

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So what, I ask?:

'To cover the vast distances between Alpha Centauri and our own solar system, we must think outside the box and forge a new way for interstellar space travel,' said Dr Chathura Bandutunga, the study's lead author.

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(.. as though covering such vast distances comes at no cost, with no assurances of returns, and is somehow not motivated purely by ego?)
But wait! There's more:

'The Breakthrough Starshot program estimates the total required optical power to be about 100 GW – about 100 times the capacity of the world's largest battery today,' said Dr Robert Ward, from the ANU Research School of Physics.

'To achieve this, we estimate the number of lasers required to be approximately 100 million.'

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Really? .. I mean, really?
(More work to do there, methinks ..)

Ponderous Curmudgeon said:

Theories make potential predictions, this is a little bit different than the popular understanding of ancient texts. For those who consider these to be relevant, we encourage you to demonstrate your relevance.

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Umm ..

FrumiousBandersnatch said:

The principle is sound enough, and could probably be useful and practical within the solar system, but this seems like a step too far. But as an ambition or aspiration, perhaps they feel that aiming high (literally!) can stimulate suitable advances in technology.

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I mostly agree.
I don't think they've been completely transparent about the steps involved in actually achieving the high velocity (0.15c) over the intervening distance, just for starters.
The project needs to be broken down into bite-sized chunks in order to convince others of its feasibility of success. The needed laser mechanism(s) to achieve the power, is a huge hurdle to be overcome. The sail itself is another unanswered issue.

This is no short-medium term project.

I get annoyed by claims (encountered elsewhere) that such projects 'can be achieved with today's technologies'. Even at a stretch, where that may be a scientifically valid statement, the engineering of this, is by no means, intuitively, a straight forward matter.

And all for what return, exactly? 'To prove' it can be done? That's not what science does .. no, this is an engineering project and should be subject to the same scrutiny any other one would.
I mean, the JWST was recently delayed again (in the last month) .. for the umpteenth time .. and that's just another telescope!

FrumiousBandersnatch said:

The Human Brain project tried this, and the necessary advances have yet to be realised.

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A tad more complexity there methinks, though ..

FrumiousBandersnatch said:

See Communication.

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Yep .. thought so .. did ya see all the propeller-head 'ideas' starting from the second page of that section?
(I even know some of them).

So many 'experts' .. with countless hours of sci-fi dreaming .. yet so little understanding of the practical engineering issues in a real world which demands a concept they are completely at loss to understand .. ie: Justification ... (which flows on from a Physical understanding of the constraints)!