Thus when Hiroko came up and said "Nadia, this crescent wrench is absolutely frozen in this position," Nadia sang to her, "That's the only thing I'm  thinking of-baby!" and took the crescent wrench and slammed it against a  table like a hammer, and twiddled the dial to show Hiroko it was unstuck, and laughed at her expression.  "The engineer's solution," she explained, and went humming into the lock, thinking how funny Hiroko was, a woman who held their whole ecosystem in her head, but couldn't hammer a nail straight.

And that night she talked over the day's work with Sax, and spoke to Spencer about glass, and in the middle of that conversation crashed on her bunk and snuggled her head into her pillow, feeling totally luxurious, the glorious final chorus of "Ain't Misbehaving" chasing her off to sleep.

###

But things change as time passes; nothing lasts, not even stone, not even happiness.  "Do you realize it's ell ess one seventy already?" Phyllis said one night.   "Didn't we land at ell ess seven?"

So they had been on Mars for half a martian year.  Phyllis was using the calendar  devised by planetary scientists; among the colonists it was becoming more common than the terran system.  Mars's year was 668.6 local days long, and to tell where they were in this long year it took the Ls calendar.  This system declared the line between the sun and Mars at its northern spring equinox to be O°, and then the year was divided into 360 degrees, so that Ls = 0°-90° was the northern spring, 90-180° the northern summer, 180-270° the fall, and 270-360° (or 0° again) the winter.

This simple situation was complicated by the eccentricity of the martian orbit, which is extreme by terran standards, for at perhelion Mars is about  forty-three million kilometers closer to the sun than it is at aphelion, and thus receiving about 45% more sunlight.  This fluctuation makes the southern and northern seasons quite unequal.  Perihelion arrives every year at Ls = 250°, late in the southern spring; so southern springs and summers are much hotter than northern springs and summers, with peak temperatures as much as thirty degrees higher.  Southern autumns and winters are colder, however, occurring as they do near aphelion; so much colder that the southern polar cap is mostly carbon dioxide, while the northern one is mostly water ice.

So the south was the hemisphere of extremes, the north that of moderation.   And the orbital eccentricity caused one other feature of note; planets move faster the closer they are to the sun, so the seasons near perihelion are shorter than those near aphelion; the northern autumn is 143 days long, for instance, while northern spring is 194.  Spring fifty-one days longer than autumn!  Some claimed this alone made it worth settling in the north.

# # #