A slender blond man who had said nothing suddenly spoke up. “You are assuming that the Mat is responding solely to your immediate actions.”

Zuminski paused, considered, and said, “That seems the simple way to go at it.”

Rachel recognized the blond man from her prepping on the Aldrin—though she had not expected to meet him here. He was Hans Stefano, the leading monitor of the Marsforming project. He had power to stop any activity if, in his documented judgment, it endangered the Mat. Originally, Stefano was to consider only how Marsforming, altering the surface and atmosphere, could interfere with the Mat’s biosphere. There were reports that he was trying to expand his reach, taking in even how the descent teams functioned below.

A pause. Hassan paid close attention, but his eyes kept straying back to Rachel. So, for that matter, did Zuminski’s.

Well, girl, Rachel thought, you wanted to make an impact, and you did.

But what next?

5.

Amazing, Rachel thought, how large a month of the hab’s shit was!

It was the next morning, and she had showed up for her task assignment. The Mars Code was, everybody works. No exception. Especially not for Earthers (no distinction here from Loonies, or Luners, as they were called here)—no tourism! Mars Operations minimized manual labor, but robots couldn’t handle everything.

But it turned out there was an exception… Fraq. He and his flock were winging it in the big overpressured dome, trying out yet another unique grav. They were having much fun while she slung shit.

Like this. First their team got the plastic bag out from the hab underskirting and onto the hauling deck of a nuclear-powered truck that growled like a caged animal, which in a way it was. It doubled as a mobile power source, 130 kilowatts electrical, able to crawl anywhere on hard, carbon-fiber treads.

They then lugged the goody bag of brown across the landscape—a big, rich gift to Mars inside a mercifully opaque plastic sack, compacted and frozen solid. The Planetary Protocols demanded that human waste be taken several kilometers from habitats, then buried in peroxide-rich sands. But not too deep—the site had to be water-poor, unable to let waste trickle down into the volumes where the Mat lived. Ecology wasn’t just some abstract science here; it was life itself. The hab used toilets that neatly separated solid and liquid waste—nature gave them separate exits, after all—and the urine got recycled, since it held 80 percent of the useful nutrients in human wastes.

Kitchen scraps, of course, went back into the greenhouses.

They had already dug the pit for it, a few klicks away across rocky terrain, using a Rover Boy backhoe. The one trick the bioengineers had not managed was converting the solid wastes to anything useful or even nonsickening. Let somebody else “realize existing in situ resources,” as the manuals had put it, by composting. Frozen, it would keep.

The superoxide and mixed chem dust was the bizarre surface chemistry’s sole advantage––it made the risk of contaminating the biosphere below tiny. Peroxides ate up fragile biological cells in seconds. Mars’s surface was the most virulent clean room in the solar system, down for five meters. Any mess that escaped, Mars would kill every single cell within an hour.