Title text:
It does come at the cost of some launchpad expansions and increased fuel requirements, but that all comes out of the facility’s budget.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3291/
https://en.wikipedia.org/wiki/Breakthrough_Starshot
Same concept really.
Eh, Niven did it first.