[X] My Assistant

[Guest_mcmcmc_*]

https://breakthroughinitiatives.org/about

Laser-powered nanocrafts headed to Alpha Centauri:

Breakthrough Starshot is a $100 million research and engineering program aiming to demonstrate proof of concept for a new technology, enabling ultra-light unmanned space flight at 20% of the speed of light; and to lay the foundations for a flyby mission to Alpha Centauri within a generation.

Which are the engineering challenges?
http://breakthroughinitiatives.org/challenges/3

Yuri Milner twitter feed (official?): https://twitter.com/yurimilner

[Gerald]

If I didn't make a mistake, I got 0.5 v/c for the energy conversion efficiency for a mirror accelerated from 0 to v by a laser beam, neglecting the Doppler shift, hence about 10% for v = 0.2c, which would be pretty good.

[marsbug]

I did some very crude calculations in bed last night and got numbers from 5% - 1%, but that was just working out how much KE the nano probe would be gaining per second given it's acceleration under kind of forces mentioned in the literature, and comparing that to the joules/second output of the power source. I had actually expected it to be much less, though I'm not really sure why. It is probably far too simplistic approach, and I wasn't going to share it, but it provides a bit of context for your numbers so here it is.