I can only assume it means creating a large, vigorously reflective surface. Not the whole moon, but presumably making a reflective, concave part large enough to send a focused beam of directed energy.
(NB: this doesn't sound like a good idea to me, or necessarily realistic, I'm just guessing that's what is meant.)
(NB: this doesn't sound like a good idea to me, or necessarily realistic, I'm just guessing that's what is meant.)