A day before the sunrise line, creeping across the face of the moon, reached Mare Nubium, the vats were filled with culture medium. At sunrise, abrupt and blinding on the airless moon, the vats were seeded, and for the next fourteen days of continuous sun they were tended, shielded, regulated, nurtured... the field workers trudging up and down the catwalks in spacesuits. As the sunset line crept toward Mare Nubium, the vats were harvested and then left to freeze and sterilize in the two week frost of the lunar night.