After a fresh February snow, a satellite about the size of a shoebox, busy snapping photographs as it circuited the planet at 17,000 miles per hour, captured something dark in Wisconsin.

About 56 tons of livestock bedding and manure had been spread atop Mark Zinke’s frozen alfalfa field.

The image eventually appeared on the computers of Stanford University researchers, who relayed it to the Wisconsin Department of Natural Resources.

Zinke, a Brownsville dairy farmer who cares for a herd of more than 1,300 cows, had forgotten about the whole thing until he later heard from the agency.

“Oh s—,” he recalled thinking at the time. “I guess we f—ed up. We gotta man up to it, right?”

Imagery collected by inexpensive satellites is ushering in an era of real-time monitoring. Some environmental advocates want the department to look down from the sky as it regulates livestock manure, a potential water contamination source.a