That said, two years after this test-firing, a 'dirty-snowball' cometary body (which had given rise to some slow-growing, anaerobic, single-celled organisms some kilo-millennia earlier) passed in front of the beam and was completely sterilized. Oh well. The comet was going to burn up in a star in another million years anyway, so it's not as if anything was actually lost. Think of it as a mercy-killing.